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I have been spending numerous hours researching the First Fuel Injection system with not a whole lot of results. I am aware of the earlier tests done when the manifold was under its original name and a couple of magazine articles way back in the day, but nothing else... Is there anyone using this system with great success? The few online dyno tests ive seen has peak power coming in at 4500 RPM on a 383 with a 220-230 cam. While the power is good, that still isn't going to cut it. I would be more comfortable using it if it was still making power at 5500 or so.
Re: Whats the deal with the First Fuel Injection TPI?
Originally Posted by Tom 400 CFI
On what engine?
My machinist and I are looking at options. It will be somewhere in the 383-409ci range. Im aware of all of the other intakes and I could use another manifold to get the job done, but I am interested in seeing results using the First.
It's basically the same idea as stock TPI but with more cfm of airflow everywhere, so the power curve is going to be very similar except it will have a higher max potential.
It's basically the same idea as stock TPI but with more cfm of airflow everywhere, so the power curve is going to be very similar except it will have a higher max potential.
How could I have missed that thread?? THANK YOU. That was pretty much what I was looking for. It also reflects an easy comparison given he is using a very well known crate engine with tons of information and carb dyno sheets for comparison.
It does indeed look like it peaks in the 4500-5000 range as I was seeing on other builds.
I believe 460-465 peak HP with a 383 TPI NA is about the max you are going to get. Some peak in the 5000s, some in higher 4000s. After peak, the HP curve pretty much flattens until max RPM.
Get in touch with TPIS (https://tpis.com/), they have built many TPI engines. They also have lots of dyno results with different set-up and intakes. I have an old book on it. They might be able to provide a digital copy.
What ever the engine you build, you take potential peak HP and deduct 10% with a TPI system like FIRST. Also the peak HP will happen at a lower RPM. FIRST has 2 different intakes, 835cfm and 1050cfm.
Richard Holdener has dyno tested a 383 with different intake including TPIs
With the OEM TPI, 411 peak HP at 5000RPM (18% loss).
With the OEM TPI extruded, 451 HP at 5900RPM (10% loss)
With TPIS TPI, 460 peak HP at 6000RPM (9% loss)
With Arizona Speed Marine TPI, 465 peak HP at 5300 (8% loss)
With TPIS mini ram, 502 peak HP at 6100RPM (0% loss)
TPI intake pretty much flattens the HP curve starting in mid 4000s.
GM rated my SP383 stroker with Chevrolet Performance Eliminator Vortec Intake Manifold, Holley 770cfm 4 barrel carburetor, 1.75" long tube headers: 435hp @ 5600rpm 445t @ 4600rpm
With a FIRST TPI, I get around 400 peak HP at 4900RPM, which is around 10% loss. However I get more average HP under 4800RPM. Peak torque happens at 3800RPM.
Here's a HP comparison:
Bottom line, you WILL NEVER get potential peak HP if you use a TPI intake. However, your average HP could be a different story. If you are looking for max HP at high rpm, TPI is not it. You might want to look at modern LS. They are hard to beat!!!!
Re: Whats the deal with the First Fuel Injection TPI?
I love your combination as its easy and should be very reliable for years to come. How is drivability and cruising? The GM crate engines may not be the best power per dollar crate available but I do know the circle track guys abuse the hell out the CT400 aka 604 crate which is basically a ZZ6 350 and they get several seasons out them. The SP383 is just a 3.750" stroke version of the ZZ6 so it's gotta be pretty close as far as reliability is concerned.
The reason I am looking into the First intake is I am spending time with a local engine builder who also has an engine dyno and we are planning out my next engine. My goal is 420rwhp and very drivable. We are thinking a 4.125" bore deal in a Dart block for around 400ci, then using Brodix IK210 CNC heads or Chad Speiers ProFilers (280-300cfm intake ports @ .500-.550). I know the extra cubes will increase the power without having to rev the snot out of it. That in turn will also make it a better driver at a given HP level. Since the First can be opened up to a 1206 intake port, it is on the list for consideration. I have a feeling it wont make the cut considering it will not keep making power in the 5500-6000 range but it might move enough air to hold a given HP figure long enough to work. All BS aside I am probably going to end up with one of the port EFI 4150 style intakes and just use an elbow. The only thing stopping me is that set up isn't very good looking and I do consider that a problem on a car that goes to shows. I'd much rather have a polished TPI system or even a polished HSR if it would fit.
I spoke to Jim twice at TPIS. Both times we were both very busy and had a lot of stuff going on which made it hard to focus for either of us on getting something nailed down. I am not opposed to Jim building my engine and I still am interested in a good conversation if we ever get time. The ideal thing would be for Ken to talk someone into making his runners shorter so we can get more RPM out of it. Yes, I do think that could be done and if done right it would be a direct swap on existing intakes. Ken bought a dyno and is starting to do his own testing. He like the rest of us is far behind and always working so finding time is hard. I SINCERELY hopes he gets it going as I would love to stay TPI for nostalgic reasons. Thanks for your info!
Re: Whats the deal with the First Fuel Injection TPI?
PS. That RCS racing engine is $30,000! I called and asked about it. While they may build a good engine, I cannot fathom spending that much for that HP level. I also disagree it needs a T56 transmission. I would think a typical wider ratio 700R4 with 3.27 gears would work just fine with that engine. I'll pass.
The GM crate engines may not be the best power per dollar crate available but I do know the circle track guys abuse the hell out the CT400 aka 604 crate which is basically a ZZ6 350 and they get several seasons out them. The SP383 is just a 3.750" stroke version of the ZZ6 so it's gotta be pretty close as far as reliability is concerned.
I got a GM crate because I could not find any good builder in my area. The SP383 is not the hottest 383 but it does the job.
The only thing stopping me is that set up isn't very good looking and I do consider that a problem on a car that goes to shows. I'd much rather have a polished TPI system or even a polished HSR if it would fit.
That was my main priority. Keeping the stock look and the Formula & TPI concept. Hell, I even kept the OEM 16in Formula wheels.
I spoke to Jim twice at TPIS. Both times we were both very busy and had a lot of stuff going on which made it hard to focus for either of us on getting something nailed down. I am not opposed to Jim building my engine and I still am interested in a good conversation if we ever get time. The ideal thing would be for Ken to talk someone into making his runners shorter so we can get more RPM out of it. Yes, I do think that could be done and if done right it would be a direct swap on existing intakes. Ken bought a dyno and is starting to do his own testing. He like the rest of us is far behind and always working so finding time is hard. I SINCERELY hopes he gets it going as I would love to stay TPI for nostalgic reasons.
That would be quite something! Bringing back the Accell Super Ram concept type of thing. Nostalgia is the main reason for holding on to these old rattly F-Bodies...hahaha!
Thanks for your info!
Anytime
Keep in mind that the DIY tuning can be a real real real pain in the a**.
Re: Whats the deal with the First Fuel Injection TPI?
Originally Posted by MrIROBZ
PS. That RCS racing engine is $30,000! I called and asked about it. While they may build a good engine, I cannot fathom spending that much for that HP level. I'll pass.
Wow!!! Just the engine alone? Because they also have a kit including transmission.
Re: Whats the deal with the First Fuel Injection TPI?
Originally Posted by SbFormula
Wow!!! Just the engine alone? Because they also have a kit including transmission.
JUST the engine. I raised an eyebrow and the guy on the phone told me its for millionaires. Not guys like me. Those were his words. Millionaires in Texas aren't hard to find, and I don't think its worth the price. As a matter of fact all the millionaires I know are VERY business minded and would probably consider that engine counter-productive for that price as most third gen's aren't even worth that (yet). Though prices are going way up. For $30k it better have an aluminum block and 15 degree cylinder heads and put out at least 750hp. But thats just me.
Re: Whats the deal with the First Fuel Injection TPI?
Originally Posted by MrIROBZ
PS. That RCS racing engine is $30,000! I called and asked about it. While they may build a good engine, I cannot fathom spending that much for that HP level. I also disagree it needs a T56 transmission. I would think a typical wider ratio 700R4 with 3.27 gears would work just fine with that engine. I'll pass.
In my opinion as someone whose car is a T56 behind a TPI I actually feel the T56 is too much shifting with the low redline and 3.27 gears. Even if you go with one of these better revving setups if you're peaking at 6000 it's still too much shifting. T56 is perfectly matched for LS. Had I done the swap again I would have done a 5-speed TKX. I did the swap before the release of the TKX so T56 it was.
Supertramp said the same thing about millionaires in Texas and that was over 40 years ago.
Re: Whats the deal with the First Fuel Injection TPI?
Originally Posted by GCrites80s
In my opinion as someone whose car is a T56 behind a TPI I actually feel the T56 is too much shifting with the low redline and 3.27 gears. Even if you go with one of these better revving setups if you're peaking at 6000 it's still too much shifting. T56 is perfectly matched for LS.
How so?
The T56 was introduced in the '92 Viper, which Peaked at ~4600 RPM...then rolled out in the '93 LT1 F-bodies next which peaked at ~5000 RPM. T56 was around for 5 years before it was finally connected to the engine you say, it was perfectly matched for, and that engine peaked at 5600 RPM. You say 6000 isn't enough. Most LS engine peak at 6000 or less. But 3 years before the start of the T56, the ZF6 was introduced with similar ratios to most T56's in the '89 Corvette, behind....the L98.
Further, gear ratios for the T56 and TKX, 1-4 (where most of driving high performance or otherwise, happens), are pretty similar. Not sure how the extra OD makes for "too much shifting"; a T56 (or ZF-6) is basically a TKX (or a T5), with one more OD.
I don't "Get it". I have had several T56's and although I'm not a fan, "too much shifting", never.....NEVER crossed my mind. Both my sporty cars currently have 6 speeds (one's an L98) and I'd like to shift 'em MORE! . You can always skip gears....you can't ever add more that aren't there.
Last edited by Tom 400 CFI; 12-11-2023 at 09:45 PM.
Re: Whats the deal with the First Fuel Injection TPI?
Regarding the debate on "too much shifting". All I can say is a blanket statement based on one's experience with one's only vehicle is flawed. There are many combination available with T56/T5 and rear gear. Tire radius as well as shift points also play a role. Driving style/preference is also important.
"Too much shifting" is subjective and not a fact that applies to all.
In my case, the swap between LB9/T5/3.42 and SP383/T56/3.89 turned out perfect. No "too much shifting". I mostly cruise on country roads and shift at low RPM to keep the noise down. I go directly from 4th to 6th most of the time, or from 3rd to 5th. The SP383 has lots of torque at lower RPM, so no need to rev to get a normal acceleration.
Here's the comparison. These numbers are confirmed with datalogs comparison with rpm calculator. The shift points are based on HP curve and best 1/4 mile.
OEM LB9, T5 (MK6) with original TPI, 3.42 gear and OEM 245s tire size
Gear/Ratio/Shift_rpm/MPH
1 / 2.95 / 5300 / 38
2 / 1.94 / 5200 / 58
3 / 1.34 / 5000 / 81
4 / 1.00 / 5000 / 108
Cruising at 50mph in 5th (0.73) = 1700RPM
Cruising at 60mph in 5th (0.73) = 2000RPM
Cruising ta 70mph in 5th (0.73)= 2350RPM
SP383 FIRST, T56 (#1386-000-011), 3.89 gear and OEM 245 tire size
Gear/Ratio/Shift_rpm/MPH
1 / 2.97 / 6000 / 38
2 / 2.07 / 6000 / 55
3 / 1.43 / 6000 / 80
4 / 1.00 / 5500 / 104 , except when drag racing, just keep going on 4th (6000rpm = 114mph)
5 / 0.80 / 5500 / 131
Cruising at 50mph in 6th (0.62) = 1600RPM
Cruising at 60mph in 6th (0.62) = 1950RPM
Cruising ta 70mph in 6th (0.62) = 2300RPM
If you compare the LB9/T5/3.42 combo vs the SP383FIRST/T56/3.89 combo, there is not much difference from 1 to 4th. So for me, going from T5 to T56, there was not "too much shifting". At cruising speed, the T56 yields lower RPM.
Back in the day, when I did the swap, there were TKO500 and TKO600 available for 5speed. Here are the numbers:
SP383 FIRST, TKO500, 3.89 gear and OEM 245 tire size
Gear/Ratio/Shift_rpm/MPH
1 / 3.27 / 6000 / 35
2 / 1.97 / 6000 / 58
3 / 1.34 / 6000 / 85
4 / 1.00 / 6000 / 114
Cruising at 50mph in 6th (0.68) = 1800RPM
Cruising at 60mph in 6th (0.68) = 2150RPM
Cruising ta 70mph in 6th (0.68) = 2500RPM
SP383 FIRST, TKO600, 3.89 gear and OEM 245 tire size
Gear/Ratio/Shift_rpm/MPH
1 / 2.87 / 6000 / 40
2 / 1.89 / 6000 / 60
3 / 1.28 / 6000 / 89
4 / 1.00 / 6000 / 114
Cruising at 50mph in 6th (0.64) = 1700RPM
Cruising at 60mph in 6th (0.64) = 2000RPM
Cruising ta 70mph in 6th (0.64) = 2350RPM
Cruising at 50mph in 6th (0.82) = 2200RPM
Cruising at 60mph in 6th (0.82) = 2600RPM
Cruising ta 70mph in 6th (0.82) = 3000RPM
If you compare the SP383FIRST/TKO500/3.89 combo vs the SP383FIRST/T56/3.89 combo, there is not much difference from 1 to 4th. At cruising speed, the T56 yields lower RPM.
If you compare the SP383FIRST/TKO600/3.89 combo vs the SP383FIRST/T56/3.89 combo, one could argue there is a little less "too much shifting" with the TKO600. At cruising speed, the T56 yields lower RPM. The TKO600 with a 0.82 would be awful on highway.
Just for fun, here's my IROC-Z bone stock.
OEM LB9, T5 (M39) with original TPI, 3.08 gear and OEM 215s tire size
Gear/Ratio/Shift_rpm/MPH
1 / 2.95 / 5300 / 43
2 / 1.94 / 5200 / 65
3 / 1.34 / 5000 / 91
4 / 1.00 / 5000 / 121
Cruising at 50mph in 5th (0.63) = 1300RPM (2100RPM in 4th)
Cruising at 60mph in 5th (0.63) = 1550RPM
Cruising ta 70mph in 5th (0.63) = 1800RPM
Seems like less "too much shifting" but in fact, I shift a lot because the gear combo makes the car slower. So I have to shift more to always get the engine in the rpm range, specially cruising on highway going uphill. 50mph cruising is in no man's land IMO. Revs either too high (4th) or too low (5th). So I am constantly shifting between 4th and 5th. Maybe that is what @GCrites80s experiences with his T56 and 3.27 gear with L98. L98 is not powerful enough and the T56 makes the engine rev at lower RPM while cruising.
Here's what @GCrites80s would get with TKX, 3.27 and 245 OEM style tires
OEM L98, T5 TKX with original TPI, 3.27 gear and OEM 245s tire size
Gear/Ratio/Shift_rpm/MPH
1 / 2.87 / 5300 / 41
2 / 1.89 / 5200 / 62
3 / 1.28 / 5000 / 88
4 / 1.00 / 5000 / 113
Cruising at 50mph in 5th (0.81) = 1800RPM
Cruising at 60mph in 5th (0.81) = 2150RPM
Cruising ta 70mph in 5th (0.81) = 2500RPM
Bottom line is, do the math before swapping anything. The engine torque/hp curve is also important. OEM TPI are not very powerful! The same transmission/gear combo can yield less shifting on a more powerful engine.
Re: Whats the deal with the First Fuel Injection TPI?
I didnt mean to start a transmission war. lol
Im getting older and while I can appreciate a manual gearbox in some cars (think an old 911 Carrera that shifts at 11k and slides around corners), my *** is staying auto for these cars. Thats all I meant by it. I'm sure a T56 is fine behind an L98. I will say this... Shifting can be fun when doing burnouts, slides, tracking etc. and it is more engaging when cruising, BUT - If you have ever ridden in a properly set up Automatic car that lunges forward on every upshift and feels crisp when cruising its very impressive! It feels like the power is being multiplied by the converter. Its simple awesome and snappy!
Re: Whats the deal with the First Fuel Injection TPI?
Originally Posted by MrIROBZ
I didnt mean to start a transmission war. lol
Im getting older and while I can appreciate a manual gearbox in some cars (think an old 911 Carrera that shifts at 11k and slides around corners), my *** is staying auto for these cars. Thats all I meant by it. I'm sure a T56 is fine behind an L98. I will say this... Shifting can be fun when doing burnouts, slides, tracking etc. and it is more engaging when cruising, BUT - If you have ever ridden in a properly set up Automatic car that lunges forward on every upshift and feels crisp when cruising its very impressive! It feels like the power is being multiplied by the converter. Its simple awesome and snappy!
I hear ya!!! Getting older too. For me it's the exhaust noise that I can't stand anymore. I also want automatic. The newer ones are faster than manual. Have a 9 speed in my Malibu 2.0T with tune. Shifts like a charm and leaves Civic SI manual in the dust!!!! 13.8 @ 102mph for a 285HP grocery getter with ventilated leather seats, adaptive cruise control, 26mpg and quiet exhaust... and less $$$ than my old '89 IROC-Z. Even have a CVT in my wife's daily.... hahaha... we are getting old!!!
Re: Whats the deal with the First Fuel Injection TPI?
My short answer is that for a street driven car it shines. If you want a high revving SBC then long tube runners isn't the answer. So depending on what your goals are for the car, that will determine if it is the intake for you.
I am sticking with the First TPI because it is a great street intake.
Like SbFormula I am noticing my "wants" drifting from what they were when I first starting building the car in my college age era. Maybe turning 30 does that to you...I am not interested in being obscenely loud and drawing all kinds of attention for all the wrong reasons. Give me a classic cruiser that is fun to drive but has AC/Heat, Bluetooth with a sound system I can actually hear, and gas mileage above my 2015 6.2L Silverado.
Re: Whats the deal with the First Fuel Injection TPI?
Originally Posted by dabomb6608
My short answer is that for a street driven car it shines. If you want a high revving SBC then long tube runners isn't the answer. So depending on what your goals are for the car, that will determine if it is the intake for you.
I am sticking with the First TPI because it is a great street intake.
Like SbFormula I am noticing my "wants" drifting from what they were when I first starting building the car in my college age era. Maybe turning 30 does that to you...I am not interested in being obscenely loud and drawing all kinds of attention for all the wrong reasons. Give me a classic cruiser that is fun to drive but has AC/Heat, Bluetooth with a sound system I can actually hear, and gas mileage above my 2015 6.2L Silverado.
Re: Whats the deal with the First Fuel Injection TPI?
Originally Posted by SbFormula
I hear ya!!! Getting older too. For me it's the exhaust noise that I can't stand anymore. I also want automatic. The newer ones are faster than manual. Have a 9 speed in my Malibu 2.0T with tune. Shifts like a charm and leaves Civic SI manual in the dust!!!! 13.8 @ 102mph for a 285HP grocery getter with ventilated leather seats, adaptive cruise control, 26mpg and quiet exhaust... and less $$$ than my old '89 IROC-Z. Even have a CVT in my wife's daily.... hahaha... we are getting old!!!
Man my wifes Explorer is faster than 90% of my hot rods. Mind you I have had a lot of cars, but her Explorer is a 20 ST twin turbo with a 10 speed and a tune. I think it makes north of 450hp with AWD and the 10 speed is lightning fast when shifting. I have a pretty dialed in butt meter and I know its in the low 12's with that tune. It bugs me when the fastest car in the house isnt the car guys car with a bitchin IROC... Its the WIFES grocery getter making 21lbs of boost while getting a butt massage. Literally the seats massage you if you want. Every car I have bought since and modify has one goal....BEAT THE EXPLODER! lol
Re: Whats the deal with the First Fuel Injection TPI?
Originally Posted by MrIROBZ
Man my wifes Explorer is faster than 90% of my hot rods. Mind you I have had a lot of cars, but her Explorer is a 20 ST twin turbo with a 10 speed and a tune. I think it makes north of 450hp with AWD and the 10 speed is lightning fast when shifting. I have a pretty dialed in butt meter and I know its in the low 12's with that tune. It bugs me when the fastest car in the house isnt the car guys car with a bitchin IROC... Its the WIFES grocery getter making 21lbs of boost while getting a butt massage. Literally the seats massage you if you want. Every car I have bought since and modify has one goal....BEAT THE EXPLODER! lol
Re: Whats the deal with the First Fuel Injection TPI?
Originally Posted by SbFormula
@dabomb6608
I'm trying staying on topic here... (maybe!)
Curious on peak HP you get with the 406cid/FIRST combo? Any dyno?
Thanks'
No dyno numbers, I've got a thread here that explains more but short story was when I was younger/dumber not only did I mess up piston selection resulting in a painfully low 7.5-8:1 compression ratio but I also likely had partially wiped cam lobes for a majority of the time that I heavily struggled with the tune/drivability. Correcting a lot of my past mistakes this go around as well as upgrading to a retro roller cam. I believe the shop I having doing my machine work has a chassis dyno...maybe one day down the road I will strap in and give it a whirl. I'm certainly not trying to build an all out monster. Plenty I could do differently to gain more, especially in the head department. But I will be more than content if it meets my goals mentioned in that post above.
Re: Whats the deal with the First Fuel Injection TPI?
Originally Posted by MrIROBZ
Man my wifes Explorer is faster than 90% of my hot rods. Mind you I have had a lot of cars, but her Explorer is a 20 ST twin turbo with a 10 speed and a tune. I think it makes north of 450hp with AWD and the 10 speed is lightning fast when shifting. I have a pretty dialed in butt meter and I know its in the low 12's with that tune. It bugs me when the fastest car in the house isnt the car guys car with a bitchin IROC... Its the WIFES grocery getter making 21lbs of boost while getting a butt massage. Literally the seats massage you if you want. Every car I have bought since and modify has one goal....BEAT THE EXPLODER! lol
That is how I feel about my Silverado. It is a 2015 Silverado LTZ with the 6.2L and Max Towing Package. It is kind of ridiculous how quick that truck accelerates for being a full size pickup. All the while having all the creature comforts I could ever ask for, a great Bose sound system, and stock exhaust that allows me to have a conversation and listen to music without it being turned to max. I've told my wife on numerous occasions, including just Sunday evening, that if anything ever happens to that truck the motor will be getting transplanted into something else.
Re: Whats the deal with the First Fuel Injection TPI?
Originally Posted by SbFormula
Regarding the debate on "too much shifting". All I can say is a blanket statement based on one's experience with one's only vehicle is flawed.
Right? That's TRUE. Note that what I said was:
Originally Posted by Tom 400 CFI
I have had several T56's and although I'm not a fan, ....
Several, in my case is 4 different T56's. Fortunately, I didn't make that flawed blanket statement, based on one's experience with one's only vehicle. I made that statement from decades of driving 3 speeds, 4 speeds, 5 speeds, and 6 speeds.....and more so, because I know....WE all know, that the T5, T56, ZF6, TKX are all essentially similar to old-skool 4 speeds; about a 3:1 first, a 1:1 4th, and somewhat evenly spaced ratios in between....Then they have an additional one OD or Two OD's. So...the discussion about "too much shifting" seems to boil down to the OD's and the use of them? I don't see how 1 vs. 2 OD's makes a meaningful diff re: "too much shifting", unless you simply press the clutch and move the lever, more than you need to. You came to a similar conclusion using numbers (the gear ratios) at the drag track....
Originally Posted by SbFormula
OEM LB9, T5 (MK6) with original TPI, 3.42 gear and OEM 245s tire size
Gear/Ratio/Shift_rpm/MPH
1 / 2.95 / 5300 / 38
2 / 1.94 / 5200 / 58
3 / 1.34 / 5000 / 81
4 / 1.00 / 5000 / 108
Cruising at 50mph in 5th (0.73) = 1700RPM
Cruising at 60mph in 5th (0.73) = 2000RPM
Cruising ta 70mph in 5th (0.73)= 2350RPM
SP383 FIRST, T56 (#1386-000-011), 3.89 gear and OEM 245 tire size
Gear/Ratio/Shift_rpm/MPH
1 / 2.97 / 6000 / 38
2 / 2.07 / 6000 / 55
3 / 1.43 / 6000 / 80
4 / 1.00 / 5500 / 104 , except when drag racing, just keep going on 4th (6000rpm = 114mph)
5 / 0.80 / 5500 / 131
Cruising at 50mph in 6th (0.62) = 1600RPM
Cruising at 60mph in 6th (0.62) = 1950RPM
Cruising ta 70mph in 6th (0.62) = 2300RPM
If you compare the LB9/T5/3.42 combo vs the SP383FIRST/T56/3.89 combo, there is not much difference from 1 to 4th. So for me, going from T5 to T56, there was not "too much shifting". At cruising speed, the T56 yields lower RPM.
Back in the day, when I did the swap, there were TKO500 and TKO600 available for 5speed. Here are the numbers:
SP383 FIRST, TKO500, 3.89 gear and OEM 245 tire size
Gear/Ratio/Shift_rpm/MPH
1 / 3.27 / 6000 / 35
2 / 1.97 / 6000 / 58
3 / 1.34 / 6000 / 85
4 / 1.00 / 6000 / 114
Cruising at 50mph in 6th (0.68) = 1800RPM
Cruising at 60mph in 6th (0.68) = 2150RPM
Cruising ta 70mph in 6th (0.68) = 2500RPM
SP383 FIRST, TKO600, 3.89 gear and OEM 245 tire size
Gear/Ratio/Shift_rpm/MPH
1 / 2.87 / 6000 / 40
2 / 1.89 / 6000 / 60
3 / 1.28 / 6000 / 89
4 / 1.00 / 6000 / 114
Cruising at 50mph in 6th (0.64) = 1700RPM
Cruising at 60mph in 6th (0.64) = 2000RPM
Cruising ta 70mph in 6th (0.64) = 2350RPM
Cruising at 50mph in 6th (0.82) = 2200RPM
Cruising at 60mph in 6th (0.82) = 2600RPM
Cruising ta 70mph in 6th (0.82) = 3000RPM
If you compare the SP383FIRST/TKO500/3.89 combo vs the SP383FIRST/T56/3.89 combo, there is not much difference from 1 to 4th. At cruising speed, the T56 yields lower RPM.
OEM LB9, T5 (M39) with original TPI, 3.08 gear and OEM 215s tire size
Gear/Ratio/Shift_rpm/MPH
1 / 2.95 / 5300 / 43
2 / 1.94 / 5200 / 65
3 / 1.34 / 5000 / 91
4 / 1.00 / 5000 / 121
Cruising at 50mph in 5th (0.63) = 1300RPM (2100RPM in 4th)
Cruising at 60mph in 5th (0.63) = 1550RPM
Cruising ta 70mph in 5th (0.63) = 1800RPM
Seems like less "too much shifting" but in fact, I shift a lot because the gear combo makes the car slower. So I have to shift more to always get the engine in the rpm range, specially cruising on highway going uphill. 50mph cruising is in no man's land IMO. Revs either too high (4th) or too low (5th). So I am constantly shifting between 4th and 5th. Maybe that is what @GCrites80s experiences with his T56 and 3.27 gear with L98. L98 is not powerful enough and the T56 makes the engine rev at lower RPM while cruising.
I don't think so. That's a rear gear problem...not a transmission problem. The L98 makes about the same tq at those low RPM's, as most any other 350 combo. About. In fact, a T56 would HELP the situation that you're describing, since 5th in the T56 is typically (typically) numerically higher ratio than 5th is a T5/or other 5 speed. Thus, you'd likely be able to climb those same hills w/a 6 speed in 5th, (with less shifting) than you can w/a T5. Oddly, I run my C4 up Mountains as part of my daily commute in 6th, which is a 0.5:1 ratio and a 3.45 rear. Does it w/o issue. At 2000 RPM (80/6th) it's making about the same tq as an L98.
Originally Posted by SbFormula
Bottom line is, do the math before swapping anything.
Agreed. Especially if you're drag racing. I didn't get the impression that @GCrites80s was specifically talking about drag racing but even if he was, all the trans's discussed (TXK, T56, T5, ZF6,)...they're ALL passing through the traps in a 1:1 gear ratio so they'll all have to shift 3 times in a 1/4 pass. I thought he was talking about "driving around", in which case, more gears gives you more ratios to choose from....you don't need to use 'em all (as we you mentioned, skipping gears). :thumbs:
Anyways, as we were, with the 383/FIRST thread.
Last edited by Tom 400 CFI; 12-12-2023 at 12:45 PM.
Re: Whats the deal with the First Fuel Injection TPI?
Originally Posted by MrIROBZ
Man my wifes Explorer is faster than 90% of my hot rods. Mind you I have had a lot of cars, but her Explorer is a 20 ST twin turbo with a 10 speed and a tune. I think it makes north of 450hp with AWD and the 10 speed is lightning fast when shifting. I have a pretty dialed in butt meter and I know its in the low 12's with that tune. It bugs me when the fastest car in the house isnt the car guys car with a bitchin IROC... Its the WIFES grocery getter making 21lbs of boost while getting a butt massage. Literally the seats massage you if you want. Every car I have bought since and modify has one goal....BEAT THE EXPLODER! lol
Originally Posted by dabomb6608
That is how I feel about my Silverado. It is a 2015 Silverado LTZ with the 6.2L and Max Towing Package. It is kind of ridiculous how quick that truck accelerates for being a full size pickup. All the while having all the creature comforts I could ever ask for, a great Bose sound system, and stock exhaust that allows me to have a conversation and listen to music without it being turned to max. I've told my wife on numerous occasions, including just Sunday evening, that if anything ever happens to that truck the motor will be getting transplanted into something else.
^Sad, but true.
IMO, these fast modern cars are fast...but boring as truck. They're robots that do it all for you; you just sit there while it runs a 13, or 12, or whatever...it doesn't even matter b/c they all feel the same and you aren't part of the experience or earning it. The days of building a bad *** car that "rules the streets" (for the most part/in your area/in your mind. ) are over, unfortunately. So what's the point in a build now days? Fun. Build for fun. And that's where the FIRST may come into play?
Re: Whats the deal with the First Fuel Injection TPI?
I am running a First intake on a GM Performance SP350/357 crate motor (rated by GM at 357HP) https://www.gmperformancemotor.com/parts/19433032.html It's certainly not a high revving motor, redline is 5600, but it's great for what I wanted. It's in a 1981 Chevy C10 truck. It absolutely rips around town and keeps pulling way past the old L98. I wanted to keep it a version of TPI as that's what I originally swapped into the truck 30 years ago, but I wanted a TPI than can actually breathe. I just got it back onto the road, I will be dyno tuning it in the spring. Don't know if the First is right for your application but I'm very happy with it.
Last edited by bloodhound1; 12-12-2023 at 04:08 PM.
Re: Whats the deal with the First Fuel Injection TPI?
Originally Posted by Tom 400 CFI
Right? That's TRUE. Note that what I said was:
Several, in my case is 4 different T56's. Fortunately, I didn't make that flawed blanket statement, based on one's experience with one's only vehicle. I made that statement from decades of driving 3 speeds, 4 speeds, 5 speeds, and 6 speeds.....and more so, because I know....WE all know, that the T5, T56, ZF6, TKX are all essentially similar to old-skool 4 speeds; about a 3:1 first, a 1:1 4th, and somewhat evenly spaced ratios in between....Then they have an additional one OD or Two OD's. So...the discussion about "too much shifting" seems to boil down to the OD's and the use of them? I don't see how 1 vs. 2 OD's makes a meaningful diff re: "too much shifting", unless you simply press the clutch and move the lever, more than you need to. You came to a similar conclusion using numbers (the gear ratios) at the drag track....
I don't think so. That's a rear gear problem...not a transmission problem. The L98 makes about the same tq at those low RPM's, as most any other 350 combo. About. In fact, a T56 would HELP the situation that you're describing, since 5th in the T56 is typically (typically) numerically higher ratio than 5th is a T5/or other 5 speed. Thus, you'd likely be able to climb those same hills w/a 6 speed in 5th, (with less shifting) than you can w/a T5. Oddly, I run my C4 up Mountains as part of my daily commute in 6th, which is a 0.5:1 ratio and a 3.45 rear. Does it w/o issue. At 2000 RPM (80/6th) it's making about the same tq as an L98.
Agreed. Especially if you're drag racing. I didn't get the impression that @GCrites80s was specifically talking about drag racing but even if he was, all the trans's discussed (TXK, T56, T5, ZF6,)...they're ALL passing through the traps in a 1:1 gear ratio so they'll all have to shift 3 times in a 1/4 pass. I thought he was talking about "driving around", in which case, more gears gives you more ratios to choose from....you don't need to use 'em all (as we you mentioned, skipping gears). :thumbs:
Anyways, as we were, with the 383/FIRST thread.
I will say in my defense that I was talking about around town stuff. So if the OEMs feel that around 50-55mph people are having to shift too often (as noted earlier) they might change the rear end gear or request the transmission supplier to raise or lower a gear or two inside it. Especially in the '80s when the speed limit was 55 all over the US. You get into the '90s and speed limits start being all over the place on highways. But then we go and swap a transmission into another car anyway and lose any kind of OEM help as far as that goes. Maybe that's why the LT1 manuals came with 3.42s paired with the same 245/50/16s the late 3rd Gens have while the auto LT1s had 3.23s. Of course the different power curve of the LT1 also became a factor.
re: skipping gears. Hey, I can do it. But it feels kind of unnatural on upshifts and some downshifts to me. I think that comes from being into motorcycles before I got into cars since bikes all have sequential gearboxes.
Re: Whats the deal with the First Fuel Injection TPI?
Also let me note my engine situation. I am about halfway between stock L98 and the hot 383s with full aftermarket intakes being discussed. Opened up air inlets/MAF, 52mm TB, ported upper plenum, SLP runners, stock unported lower, mild cam, mid-length headers, aftermarket exhaust, a mild tune that mostly has spark table changes. So I've got a little more RPM headroom than stock but not a lot.
Re: Whats the deal with the First Fuel Injection TPI?
Originally Posted by GCrites80s
Also let me note my engine situation. I am about halfway between stock L98 and the hot 383s with full aftermarket intakes being discussed. Opened up air inlets/MAF, 52mm TB, ported upper plenum, SLP runners, stock unported lower, mild cam, mid-length headers, aftermarket exhaust, a mild tune that mostly has spark table changes. So I've got a little more RPM headroom than stock but not a lot.
Cool, I "feel" ya. I'm similar, minus the cam, but trying a bunch of different intakes, in THIS THREAD, where I'm trying to re-create the old "Ten Times the Torque" article, but with a more stock engine instead of a 500 hp 383. I hope to test a FIRST at some point, but a prototype GM intake is next (on the engine already, but snowed-in, here), so I can't possibly test until next spring at this point.
Some of them definitely will cause you to shift more while cruising around town. I took the gear ratios listed in Wiki and whipped up these graphs in a spreadsheet.
Let's say you like to cruise between 1700 - 2500 rpm. These are the MPH you will be traveling in each gear with that constraint. The more overlap of the lines between gears, the less shifting you'll need to do while putting around town. Some of these transmissions have very little to no overlap between the 2/3 and 3/4 gears. That will either make you rev your engine higher, or make you want to shift more hunting for the right gear.
Re: Whats the deal with the First Fuel Injection TPI?
Sure? I guess so? I mean, you can cherry pick any number of driving scenarios, and then transmission options to make the point, but the TKX, the T5, the T56, all have and can be had with about the same gear ratios. Of course, each trans has a selection of ratios to pick from....so you could pick the "worst" of one and the "best" of another to try to make the point....but that's a stacked way to do it. All three, have about the same lowest 1st ratio, all three have about the same highest 1st ratio, all three have a 1:1 4th ratio. Optioned or selected similarly, there is basically no meaningful driving differences between any of them, until you hit OD(s), then the 6 speeds give you more ratio options, and typically a taller 6th, than any 5-speeds 5th... which is hard to argue as a detriment.
Also, we're all fortunate to own cars with engines that are very flexible, with a lot of torque down low, in the middle and higher up, too.....eliminating the need to create weird scenarios like X rpm to Y rpm, that we'd likely not limit ourselves to in real driving.
Re: Whats the deal with the First Fuel Injection TPI?
Originally Posted by Tom 400 CFI
Cool, I "feel" ya. I'm similar, minus the cam, but trying a bunch of different intakes, in THIS THREAD, where I'm trying to re-create the old "Ten Times the Torque" article, but with a more stock engine instead of a 500 hp 383. I hope to test a FIRST at some point, but a prototype GM intake is next (on the engine already, but snowed-in, here), so I can't possibly test until next spring at this point.
Wow, what a great thread! So I'm not the only one who only ever saw 500hp builds in these shootouts that didn't give us the variables set we need with our boring heads, compression and cams. I mean, I do want to do that stuff sometime in the future but as far as now goes...
I didn't know there were multiple iterations of the SLP runners. I have the early siamesed ones and I siamesed my upper plenum to match them. There are a lot of period-correct aftermarket parts on this car like the Walker Super Turbo muffler, early Edelbrock headers and the ADS Superchip adapter.
My T-56 is out of a '96 Trans Am so it has a lot of overlap. So I'd really be whining if I had a '93 transmission. I made sure to avoid one of those but there's some people over at FRAAX that are like "Let me at it! Especially an M28!" for autocross.
Re: Whats the deal with the First Fuel Injection TPI?
Originally Posted by Tom 400 CFI
there is basically no meaningful driving differences between any of them, until you hit OD(s)
You're wrong. Transmission gear ratios matter.
You know the difference between you and me? I listen. I listened to GCrites80s own personal experience and didn't argue. I wasn't thrown into despair and panic that his "cause and effect" is flawed. I found the positive in what he said and tried to validate that part of it and maybe help explain why it happens.
All you see is the negative and you latch onto it like a pitbull and won't let go. Just shut up and let the man breath.
Re: Whats the deal with the First Fuel Injection TPI?
Glad you like the other thread. I'm pretty happy about how it's all worked out, so far. It's my "mid life crisis": Testing all these intakes that I couldn't afford when they were new, for cars I couldn't afford when they were new!
I had those early Edelbrock TES headers on my TA too! They were pretty good. Didn't leak, didn't rot out, lasted a long time....and they help power, a lot. Never got into the other parts, I had an SLP TOTL and CFI, so no runners for me.
I had a '93 T56, and thought it was fine. I'd had a T5 prior and didn't notice the diff in ratios when I changed 'em, so..... I worked at a salvage yard in '93, a wrecked LT1 F-bod came in and I grabbed that trans...I was probably one of the first people in the country to put one in a 3rd gen. No one was making x-members for them back then so I fabbed my own and let me tell you, my fabbing skills back then were minimal. I "willed" an x-member out of 1/2" plate steel!! Anyway, it worked for years, then I traded the whole assy for another T5 and I was back to a 5 speed....never noticed the diff in ratios then, either.
Re: Whats the deal with the First Fuel Injection TPI?
Originally Posted by QwkTrip
You're wrong. Transmission gear ratios matter.
You know the difference between you and me? I listen. I listened to GCrites80s own personal experience and didn't argue. I wasn't thrown into despair and panic that his "cause and effect" is flawed. I found the positive in what he said and tried to validate that part of it and maybe help explain why it happens.
All you see is the negative and you latch onto it like a pitbull and won't let go. Just shut up and let the man breath.
Good for you! You're THE MAN!
I wonder though....Did I say that "Trans gear ratio's don't matter?" I don't believe that I did....
That was a WHOLE lot of ASSumptions in a few sentences! Yikes. Now, let me try, too!:
You know the difference between you and me? I actually understand how cars work (30+ years of ASE certs and managing shops helps). I like to seek out and share fact for the benefit of others. I like for folks to learn-a-thing, and I'm happy to learn-a-thing, too! All you do is pass on misinformation, manipulate the point to get any kind of "win" that you can, make up absurd scenarios to "win" your erroneous point, and you're perfectly happy to remain ignorant in the process.
How'd I do? Was reading that as fun for you as yours was to read, for me? I think both were pretty unnecessary, stupid and competely irrelevant to the discussion. But, insults is a place people like to go to, when they're challenged sometimes, unfortunately.
It's no big deal, man. If you think a 6 speed makes you "shift too much"....get an automatic, and give 'er hell. I don't care. Geezus.
Re: Whats the deal with the First Fuel Injection TPI?
Well… that escalated quickly…
Moving on…
I got a call from Jim Hall a few days ago and we discussed a new engine for me. We’re thinking 400-415ci, First intake, around 9.6:1, 220-230 duration, and AFR 195 heads which should keep the port speed up. From my calculations on PIPEMAX, 300-311 FPS would create more power over a bigger head where the airspeed runs a little slower. Am I way off here? I have no problems going to a 210 if needed. The idea is to have a very well driving car that still hangs with new stuff. My goal is 11.7 with good traction on pump 93.
Re: Whats the deal with the First Fuel Injection TPI?
Originally Posted by MrIROBZ
Well… that escalated quickly…
Moving on…
I got a call from Jim Hall a few days ago and we discussed a new engine for me. We’re thinking 400-415ci, First intake, around 9.6:1, 220-230 duration, and AFR 195 heads which should keep the port speed up. From my calculations on PIPEMAX, 300-311 FPS would create more power over a bigger head where the airspeed runs a little slower. Am I way off here? I have no problems going to a 210 if needed. The idea is to have a very well driving car that still hangs with new stuff. My goal is 11.7 with good traction on pump 93.
What kind of exhaust are you looking at? Dual 2 1/2" or single 3" Y to 4". Headers 1 3/4" primary? You will probably be close to 500hp with that set-up! Monster torque?
Re: Whats the deal with the First Fuel Injection TPI?
Have you considered having a sheet metal intake made that will fit under the hood? That might better optimize the intake for your engine... really let it run.
You can easily get into a situation where the car is "hard to drive hard". My first LS stroker was like that. It made soooo much torque down low and mid-range you couldn't use the throttle on any public roads or the tires would light up. My next build made even more torque and more power but at higher RPM and it is amazing how much a difference it made. The car is much easier to drive hard, better throttle control, and car is much faster. I put a lot of money in the cylinder heads and intake with engine #2 and the result is +100 RWHP with no loss of low rpm drivability.
Re: Whats the deal with the First Fuel Injection TPI?
Originally Posted by SbFormula
What kind of exhaust are you looking at? Dual 2 1/2" or single 3" Y to 4". Headers 1 3/4" primary? You will probably be close to 500hp with that set-up! Monster torque?
$30K??
Dyno Dons 1 3/4" going to a mufflex 3.5-4" - IF he decides to make them again. Theres a thread going that is getting orders ready for a group buy.
No, not even. Wouldnt pay 30k for a street engine unless it was a lot more power.
Re: Whats the deal with the First Fuel Injection TPI?
Originally Posted by QwkTrip
Have you considered having a sheet metal intake made that will fit under the hood? That might better optimize the intake for your engine... really let it run.
You can easily get into a situation where the car is "hard to drive hard". My first LS stroker was like that. It made soooo much torque down low and mid-range you couldn't use the throttle on any public roads or the tires would light up. My next build made even more torque and more power but at higher RPM and it is amazing how much a difference it made. The car is much easier to drive hard, better throttle control, and car is much faster. I put a lot of money in the cylinder heads and intake with engine #2 and the result is +100 RWHP with no loss of low rpm drivability.
I have. I have considered buying a used stealth ram or even MR and HSR. I'd prefer to stay TPI and use a First. I think I could hit my goals with a 383 using a little more head than the lingenfelter with a First and a 219 cam. I know I could get close anyway. I COULD actually do a 396 for 10 more ftlbs.. Maybe 10 more hp over a 383. Run a 4.030" bore for more valve unshrouding. I know one of the problems with TPI is the airspeed in the ports. At peak TQ with high compression you get detonation due to cylinder pressures being so high. Ive even thought about going LT1 with reverse cooling and then using a first intake that Ken makes for the LT1 that even has a distributor hole. The problem I run into there is I dont like the front accessory issue where you have to notch the K member to run AC. I know I could use Vette front accessories and I am still looking into that. Regardless, with a SBC I think high compression (Over 10.1) with TPI might produce some problems on pump gas.
Re: Whats the deal with the First Fuel Injection TPI?
I built a modified 383 TPI several years back, and a similar engine with an HSR put down about 385 to the rear wheels. My guess is that mine was "similar" on the butt dyno. It had an absolute boatload of torque, and ran out of breath real fast. -as expected by 4 decades of research, the TPI came on quick, then quickly left the party! I really wanted the TPI underhood, but.....no doubt a different cam and intake that rev'd up a bit higher would've been every bit as fun. I knew what I was doing, and it LOOKED great, so no complaints here, but.... ....just KNOW what you're getting into with that TPI.
Re: Whats the deal with the First Fuel Injection TPI?
Jesus, man. You've got some serious personal issues.
That's the POINT of PM. To not f-up the thread. You've gone the opposite way and taken a PM to a thread!? Yikes. I don't GAF about your "warning", either. You're not a mod, I've done nothing wrong, You do not tell me what I can and can't post, when to "shut up", or what my content can be....Hypocrite.
Re: Whats the deal with the First Fuel Injection TPI?
Originally Posted by Abubaca
I built a modified 383 TPI several years back, and a similar engine with an HSR put down about 385 to the rear wheels. My guess is that mine was "similar" on the butt dyno. It had an absolute boatload of torque, and ran out of breath real fast. -as expected by 4 decades of research, the TPI came on quick, then quickly left the party! I really wanted the TPI underhood, but.....no doubt a different cam and intake that rev'd up a bit higher would've been every bit as fun. I knew what I was doing, and it LOOKED great, so no complaints here, but.... ....just KNOW what you're getting into with that TPI.
They sure look pretty though.
That’s a damn good looking motor dude. I don’t envy many things but I dig the colors. Especially the headers.
Re: Whats the deal with the First Fuel Injection TPI?
That’s a damn good looking motor dude. I don’t envy many things but I dig the colors. Especially the headers.
Thanks!!!!!! ...yeah, we have JET HOT here local to me. I was in the showroom with the headers and Y pipe and I was looking at gold and bronze colors since my 89 had the gold/tan accents. Thought it would look good but the color samples weren't doing it any justice and I had actually decided to just go with the standard polish/chrome finish. ....then a guy rolls a rack full of ducati exhaust in THAT bronze color right by the counter and I was like "THAT IS THE COLOR!!!!" I was sold!!
12-09-2023, 01:45 PM
. You can always skip gears....you can't ever add more that aren't there. 
Especially if you're drag racing. I didn't get the impression that @GCrites80s was specifically talking about drag racing but even if he was, all the trans's discussed (TXK, T56, T5, ZF6,)...they're ALL passing through the traps in a 1:1 gear ratio so they'll all have to shift 3 times in a 1/4 pass. I thought he was talking about "driving around", in which case, more gears gives you more ratios to choose from....you don't need to use 'em all (as we you mentioned, skipping gears). :thumbs:
