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I, my father Dyno Don, Allan (1989GTATransAm) and JerryWho, spent several years back then trying to figure out what made TPI tick, and we discovered you CAN get TPI to make more horsepower if you shorten the runners. We shortened them by siamesing a set of SLP runners. As was mentioned in this thread, the long runners help torque at idle-3500 but they severely limit it above 5000 rpms.
Hey Kevin, yeah Ive read that post several times. Let me lay this out for you. HP is a function of TQ times speed. If TQ is the force you get work done, HP is the speed at which you do that work. You cannot have HP without RPM. This is why the obvious answer for getting more HP is by turning more RPM. But theres other routes.
Piston speed causes a demand as for the CFM needed to fill a cylinder. Part of the reason strokers make more HP is by increasing that demand by adding more stroke (and some more bore too) which creates more piston demand to move more air and provide more HP. In strokers, that result is often moving the peaks LOWER in the RPM range, given the same exact combination of parts. They add HP without increasing RPM. Whats basically happening here is the total airflow demand has increased and by putting more into the cylinder that has increased the power.
Another way that increases the CFM delivered into the cylinder is forced induction, which I am not going in length on... and...
Yet even another way to do this is to increase the VE of a given engine by inertia ramming air into the cylinder after bottom dead center making the cylinder carry more air needing more fuel which results in making more power.
What does all this have in common? Total CFM delivered into a cylinder for an increase in power. What you guys did is shorten the runners and increase the port sizes for more RPM and airflow. What I am doing is increasing the port sizes to a specified CSA while also carefully maximizing the port airspeed velocities for more inertia ramming to maximize TPI LTR average power production. They are not exactly the same thing. You guys didn't even take any CFM measurements with the whole system bolted together nor did you provide any pitot tube readings to correlate what your trapped VE was. Theres a lot of questions I still have and this is an attempt at trying to get some answers while fixing a couple problems.
There were a lot of pages explaining this in detail with links that I erased but basically by increasing the port airspeeds with a carefully chosen port size, you can inertia ram the cylinder making a 350 have the output of a larger engine for more average and peak horsepower.
Ok, thread pretty much restored but I included more tech for formulas and condensed a lot of it. There was a lot of talking out loud moments and asking questions before that nobody seemed to answer.
Update. Spoke with Charlie today and came across an answer for a question I have been asking. For those that remember I posted a graph that showed a TPI long tube runner engine built by Jim Hall at TPIS pulling to 6000rpm, and the curve looked a little different than normal. Well.... I have had this theory thats been shot down but today I learned I was RIGHT. Look at this graph and the one below it... Why do you think they look different despite being the same intake length and minimal differences in flow? Ignore the fact one is at the tire and one is at the crank.
I, my father Dyno Don, Allan (1989GTATransAm) and JerryWho, spent several years back then trying to figure out what made TPI tick, and we discovered you CAN get TPI to make more horsepower if you shorten the runners. We shortened them by siamesing a set of SLP runners. As was mentioned in this thread, the long runners help torque at idle-3500 but they severely limit it above 5000 rpms.
Ok, thread pretty much restored but I included more tech for formulas and condensed a lot of it. There was a lot of talking out loud moments and asking questions before that nobody seemed to answer.
Update. Spoke with Charlie today and came across an answer for a question I have been asking. For those that remember I posted a graph that showed a TPI long tube runner engine built by Jim Hall at TPIS pulling to 6000rpm, and the curve looked a little different than normal. Well.... I have had this theory thats been shot down but today I learned I was RIGHT. Look at this graph and the one below it... Why do you think they look different despite being the same intake length and minimal differences in flow? Ignore the fact one is at the tire and one is at the crank.
The answer I believe is not the dyno headers as we initially thought. When I look at recommended MSCA,(page 1 courtesy of Chad Speier) you see a 350 for 320fps wants a 1.93" csa. However looking at AFR heads, the 180cc has a 1.810" pinch, while the 195cc has a 1.905" pinch. The Vortec 190 used on Jims motor? 2.05" CSA!
For those that dont know what a pinch is, most heads have the smallest area at the valve. Now this is ideal because that is where all the signal for the pressure drop comes from. Pressure always moves from high to low. A small block Chevy head (and a couple others) have a different architecture because engineers had to make it compact, but because of this the pushrods create a wall in the port (short side) which makes that the smallest CSA in the intake port. The trick there is to use the coanda effect and slow the air down around the short wall and set it up to make that big short turn radius.
Take a look at Richard Holdeners videos. He has a 10.5:1 355 with AFR195 heads on it where he tried to get 500ft lbs out of it. Remember that? That motor, with a 218/224 110 .498/.502 cam made 372hp @ 4700 and 465ft lbs @ 3700.
Jims graph above, is also a 355 with 9.6:1 and is using Vortec 190 heads (bigger MCSA) but pulls cleanly to 396hp@ 5900 but makes less TQ (452) at a higher 3900. Im sure there was some timing/tuning involved but this bigger MCSA didnt hurt when TPI is already at small CSA with turns and bends in the intake path. Would I recommend this on a shorter carbureted intake manifold? No. I would not. But I think doing this with TPI does a few things... For one, TPI already has a small port and harmonics which are trying to give the engine 6000rpm. Two, by removing some of the restriction in the PRP, the engine could be giving a much better and stronger signal to the intake manifold and allowing the air more energy to overcome the long runner path and obstacles that are in the way.
Both were using long tube headers for the dyno. Both were 355's. Both were ran by experienced dyno operators wanting consistency. Both were using AFR heads with similar size and ports. Both were using the same runners. Both were using ported bases and both were using port matched plenums and both had cams in the 218-224 range with about the same lift and LSA!
So, in a nutshell, is what you're saying that Hall's 350 making power to 6k is the result of a larger CSA? 2.05" vs 1.905" vs 1.810".
And by CSA what's really meant is the pushrod pinch which is the case of most SBC heads (that I'm aware of) and would be the Minimum CSA correct?
My business site showed a link to the velocity spreadsheet.
Looks like the thread went off the rails.
I'd be happy to answer and questions about it.
Just ask.
My business site showed a link to the velocity spreadsheet.
Looks like the thread went off the rails.
I'd be happy to answer and questions about it.
Just ask.
Its back on track. Thanks Chad. I do have a question. Is that link still there? Ive been to your site a few times and I hadn't seen it until you sent me that pic. Thanks.
My business site showed a link to the velocity spreadsheet.
Looks like the thread went off the rails.
I'd be happy to answer and questions about it.
Just ask.
Originally Posted by MrIROBZ
Its back on track. Thanks Chad. I do have a question. Is that link still there? Ive been to your site a few times and I hadn't seen it until you sent me that pic. Thanks.
I too have been to Chad's website more than once although I hadn't realized the "Cylinder Head Math" tab until Rob's thread brought it to the fore.
I spent a good chunk of my afternoon noodling around with the numbers and comparing it to the heads I have now.
I'm also happy that the thread was restored and am looking forward to further dialogue.
Okay... . Im committed to the project and I would like to see others give their 2 cents even if they disagree on whats going to happen. If my math is incorrect, or even the whole theory, I am up for that and talking about it. Respectfully.
You know, I've danced around the subject but haven't found a response to my inquiry.
Some of my insight: We're all aware, or should be anyway, how a tuned length open collector will enhance scavenging of the combustion chamber and improve VE. The inverse is also true in that a secondary of the wrong length will reduce engine output. Worse even than if a full exhaust were hanging off of the backside in many cases.
The induction has the same tuning effect in play does it not? A length will have a particular resonance and if this resonance corresponds with the IVO event, then there's an enhancement to the cylinder fill. I'm pretty sure I've got that right.
So, in some of my modelling, I can see where an induction length (including port) of 11.5", will produce peak torque and HP at let's say RPM "X". Now extend the induction length to 22+", which is TPI territory and those RPM peaks are "X" minus about 2500 RPM. Is this a case where, as in the exhaust, a length not suited to the RPM range targeted, there could be a detrimental effect with respect to cylinder filling?
Is this a real limitation in getting the TPI to give higher peak RPMs?
So, in a nutshell, is what you're saying that Hall's 350 making power to 6k is the result of a larger CSA? 2.05" vs 1.905" vs 1.810".
And by CSA what's really meant is the pushrod pinch which is the case of most SBC heads (that I'm aware of) and would be the Minimum CSA correct?
a tuned length open collector will enhance scavenging of the combustion chamber and improve VE. The inverse is also true in that a secondary of the wrong length will reduce engine output. Worse even than if a full exhaust were hanging off of the backside in many cases.
The induction has the same tuning effect in play does it not?
That's true. Back in post #48:
Originally Posted by Tom 400 CFI
That runner length enhances torque at ~3200 RPM, and hurts it to an equal extent during the opposite phase/frequency. At ~5000 RPM it's hurting tq by a similar magnitude.
For reference, a ported stock intake can flow right around 245-260cfm depending on the bench and whos porting it. This may be enough to match the ASM runners for cfm, but just because you can get 260cfm out of once piece, and you get 260cfm out of the next doesnt mean youll end up with 260cfm total flow. Intake components all have a resistance to flow and that resistance is like series resistors in an electrical schematic. You may get 260 cfm out of the runners and base but bolted together you are looking more like 235cfm. Initially I was going to do this job with a SDPC vortec base, but parts availability and the discovery of total flow ported made me cancel that idea and grab a better base. This actually worked out fine because the head I ended up needing is better for the job anyway thanks to the port sizes.
the asm runners flow more than 260 when flowed alone, i have gotten the stock runners to flow 270, the asm can also be "opened up" even more, the cast runners need work to get to flow good, the edelbrock are the closest to the ASM in terms of length flow and size
your tpis base is the same as an edlebrock 3860 but doesnt have the tpis clean up work done to it, it should flow around 260 as is
If you can't find it by the end of the (work) day -I'm working today, post and I'll measure mine when I get home.
the stock intake is 13 inches this is shortest length for base and stock runners, the accel and slp runners are a tad shorter than stock the asm and edelbrock are a tad longer all three have a different curve shape
when porting cast runners imo its best to not siamese far back you dont want the runner opening covered imo you want the divider to still be somewhat facing the plenum if you need more top end power and desire to cut the divider further down imo you will need to siamese all for runners
So, in a nutshell, is what you're saying that Hall's 350 making power to 6k is the result of a larger CSA? 2.05" vs 1.905" vs 1.810".
And by CSA what's really meant is the pushrod pinch which is the case of most SBC heads (that I'm aware of) and would be the Minimum CSA correct?
Sorry Skinny, I didnt even see your question. Jim Halls entire dyno curve is a result of using a bigger MCSA IMO. Not just his average CSA.... there are the Average CSAs and Minimum CSA's.Average CSA being the average port size. Minimum being the pushrod pinch in a SBC or the valve curtain in other heads. I firmly believe TPI can use a bigger pinch if the right size port is used because the average CSA is already small, the port is very long and restrictive and the airspeeds, the math and the dyno tests shows this. If im wrong... ill be wrong. I can live with it but I know itll still work well, regardless.
the asm runners flow more than 260 when flowed alone, i have gotten the stock runners to flow 260, the asm can also be "opened up" more, the cast runners need work to get to flow good and the edelbrock are the closest to the ASM in terms of length flow and size
your tpis base is the same as an edlebrock 3860 but doesnt have the tpis clean up work done to it, it should flow around 260 as is
We haven’t gotten any testing of our own done yet because they are on back order. I’m going off what they claim https://azspeed.com/product/1989-199...ntake-runners/ and I’d be interested in seeing what they look like on the bench.
From my calculations they flow less than what they claim. At a 2.08 CSA of a straight port it would take 300fps to hit 260cfm. The runners are circular which helps but the radius lessens that output.
Ive looked for flow coefficient charts and calculators to determine the difference between a circular shape vs a square and rectangle at a given CSA but I’ve only found HVAC and hydraulic information.
The important take away for people to think about is because the higher flowing circular shape is also a radius, the difference in coefficients is no longer a factor.
This is all why when people say/think flow isn't important, they are wrong. While it might not be #1 on the list, all sizing of the induction should be based off a target velocity.
At the end of the day, no matter what the engine combo is, we are all running the same average airspeed in the induction.
Usually you will never get the 3rd harmonic under a hood, so I'd shoot for the 4th.
So a typical vortec headed 355 that peaks at 6000 would be 10.000 total
Runner length data from PipeMax...
Bore=4.00000 Stroke=3.48000 349.84775790 Cubic Inches @ 6000 RPM Intake System= 113.57909 VE%
Complete Intake System Flow @28in.= 217.4417 -to- 232.8492 CFM @ 0.537000 Lift (22.23000 VE% Loss)
Cylinder Head Intake Port Flow @28 inch = 260.0000 -to- 278.4230 CFM at 0.64199 Lift (135.80909 Ve%)
---- Induction System Tuned Lengths ---- ( * Open-End Tube = both Odd and Even Numbered Harmonics )
Harmonic Total Intake Manifold Air / Fuel Ratio = 13.20000:1 BSFC = 0.6469 LbsHour/HP
Wave Induction Port Runner ( Induction System operating RPM Range from 4000 to 6500 RPM )
Number Length Length Length ------ Description --------------------------------------------
1st 40.3309 = 5.3330 + 34.9979 typically Induction Length too long to fit or use effectively
2nd 20.1654 = 5.3330 + 14.8324 creates the highest Peak Torque, but may lose higher RPM HP
3rd 13.4436 = 5.3330 + 8.1106 ProStock, Comp Eliminator, etc. best Peak TQ and Peak HP Combo
4th 10.0827 = 5.3330 + 4.7497 Single-Plane Manifold, slightly less Torque than 3rd Harmonic
5th 8.0662 = 5.3330 + 2.7332 Peak Torque is substantially reduced, even though Tuned Length
Note: 1st and 2nd Harmonic Lengths sometimes create the highest Peak Torque, but may lose higher RPM HP
the 3rd Harmonic Length typically creates the best overall combination of Peak Torque and Peak HP
the 4th Harmonic's shorter Tuned Length allows for greater underneath Hood clearance
Note: all the above Induction System Tuned Lengths are based-off 0.500 inch Radius Entry Curve
if your Radius Entry is less, the Power Curve will be shifted slightly to a lower RPM Range
if your Radius Entry is greater, the Power Curve will be shifted slightly to a higher RPM Range
* Radius Entry Curve = Bellmouth Radius, Carb Entry Radius, Velocity Stack Radius, Plenum Entry Radius
_______________________________________________________________________________________________________
----- Intake Manifold Plenum Runner Entry Area ( * with 0.500 inch Radius Entry Curve ) -----
Minimum Recommended Entry Area = 2.773 to 3.120 Sq.Inch ( minimum for 1 Carb Single-Plane Manifolds )
Average Recommended Entry Area = 3.189 Sq.Inch ( good for Single-Plane or Tunnel Ram Manifolds )
Maximum Recommended Entry Area = 3.257 to 3.854 Sq.Inch ( maximum for 1 Carb Single-Plane Manifolds )
Minimum Plenum Volume CC = 802.6 or CID = 49.0 ( typically for 1 Carb Single-Plane Manifold )
Single-Plane Manifold with 1 Carb Recommended Plenum Entry Area = 3.257 to 3.854 Sq.Inch
Maximum Plenum Volume CC = 5733.0 ( typically for Tunnel Ram Intake Manifold with Carbs, MFI, EFI )
Maximum Plenum Volume CID= 349.8 ( typically for Tunnel Ram Intake Manifold with Carbs, MFI, EFI )
Tunnel Ram Intakes with direct-line-of-sight Carb Bores Recommended Entry Area = 2.773 to 3.257 Sq.Inch
Tunnel Ram Intakes with poor-line-of-sight Carb Bores Recommended Entry Area = 3.257 to 3.854 Sq.Inch
_______________________________________________________________________________________________________
Induction System Tuned Length ( with Injector Stack Bellmouth or Radius Entry ) • ( No Plenum Area )
* definition : from Head's Valve Seat Lap-Line -to- top of Injector Stack Bellmouth or Radius Entry
Induction System Tuned Length ( with IR = Independent Runner and Carb ) • ( No Plenum Area )
* definition : from Head's Valve Seat Lap-Line -to- top of Carb Entry Area or Velocity Stack Radius
Induction System Tuned Length ( with Intake Manifold that has a Plenum Area )
* definition : from Head's Valve Seat Lap-Line -to- Intake Runner Entry Area inside Manifold Plenum
CSA data from PipeMax
Bore=4.00000 Stroke=3.48000 349.84775790 Cubic Inches @ 6000 RPM Intake System= 113.57909 VE%
Complete Intake System Flow @28in.= 217.4417 -to- 232.8492 CFM @ 0.537000 Lift (22.23000 VE% Loss)
Cylinder Head Intake Port Flow @28 inch = 260.0000 -to- 278.4230 CFM at 0.64199 Lift (135.80909 Ve%)
Intake Intake Average Minimum Intake Port Flow @28 inches = 260.0000 CFM at 0.537000 Valve Lift
Velocity Cross-Sectional Intake Port 6000 RPM ( RPM Range = 4000 to 6500 RPM )
FPS Area sq.inch Volume CC's ----- Description --------------------------------
350 1.78286 CSA 155.8 Port has Pumping-Choke with HP Loss ( too fast FPS • HP Loss )
330 1.89091 CSA 165.3 Port may have Pumping-Choke with HP Loss ( too fast FPS )
311 2.00643 CSA 175.3 Highest useable Port velocity ( good TQ + HP • possible HP loss )
300 2.08000 CSA 181.8 Smallest Port CSA ( Hi Velocity FPS • very good TQ and HP )
285 2.18947 CSA 191.3 Recommended Port CSA ( very good TQ and HP combination )
260 2.40000 CSA 209.7 Recommended average Intake Port CSA (very good TQ and HP)
250 2.49600 CSA 218.1 Largest recommended average Intake Port CSA ( good HP )
240 2.60000 CSA 227.2 Largest recommended average Intake Port CSA (less Peak TQ)
235 2.65532 CSA 232.1 Largest recommended Intake Port Gasket Entry area CSA
225 2.77333 CSA 242.4 Largest Intake Port Gasket Entry CSA ( Slow FPS )
215 2.90233 CSA 253.6 Possible Torque Loss with Reversion ( Slow FPS )
210 2.97143 CSA 259.7 Torque Loss + Reversion possibility ( too slow FPS )
200 3.12000 CSA 272.7 Torque Loss + Reversion possibility ( too slow FPS )
304.7 2.04807 CSA 179.0 260.0000 CFM = User's Intake Port Flow at 0.537000 Valve Lift
Exhaust Exhaust Average Minimum Exhaust Port Flow @28 inches = 207.0000 CFM at 0.537000 Valve Lift
Velocity Cross-Sectional Exhaust Port 6000 RPM ( RPM Range = 4000 to 6500 RPM )
FPS Area sq.inch Volume CC's ----- Description --------------------------------
435 1.14207 CSA 54.3 Port and Throat Area have Pumping-Choke (too fast FPS • HP Loss)
380 1.30737 CSA 62.1 Port may have Pumping-Choke with HP Loss ( too fast FPS )
350 1.41943 CSA 67.5 Highest useable Port velocity ( possible HP loss • too fast FPS )
330 1.50545 CSA 71.5 Highest useable Port velocity ( good TQ + HP • possible HP loss )
311 1.59743 CSA 75.9 Highest useable Port velocity ( very good TQ and HP combination )
300 1.65600 CSA 78.7 Recommended Port CSA ( very good TQ and HP combination )
285 1.74316 CSA 82.8 Recommended average Exhaust Port CSA (very good TQ and HP)
265 1.87472 CSA 89.1 Recommended average Exhaust Port gasket area at exit
240 2.07000 CSA 98.4 Recommended largest Exhaust Port gasket area at exit
225 2.20800 CSA 104.9 Largest Exhaust Port Exit gasket area at exit (Slow FPS)
210 2.36571 CSA 112.4 Largest Exhaust Port Exit gasket area at exit (Slow FPS)
190 2.61474 CSA 124.3 Torque Loss + Reversion + Scavenging loss (too slow FPS)
180 2.76000 CSA 131.2 Torque Loss + Reversion + Scavenging loss (too slow FPS)
363.2 1.36777 CSA 65.0 207.0000 CFM = User's Exhaust Port Flow at 0.537000 Valve Lift
Bore=4.00000 Stroke=3.48000 349.84775790 Cubic Inches @ 6000 RPM Intake System= 113.57909 VE%
Complete Intake System Flow @28in.= 217.4417 -to- 232.8492 CFM @ 0.537000 Lift (22.23000 VE% Loss)
Cylinder Head Intake Port Flow @28 inch = 260.0000 -to- 278.4230 CFM at 0.64199 Lift (135.80909 Ve%)
Intake Intake Average Maximum Intake Port Flow @28 inches = 278.4230 CFM at 0.641992 Valve Lift
Velocity Cross-Sectional Intake Port 6000 RPM ( RPM Range = 4000 to 6500 RPM )
FPS Area sq.inch Volume CC's ----- Description --------------------------------
350 1.90919 CSA 166.8 Port has Pumping-Choke with HP Loss ( too fast FPS • HP Loss )
330 2.02489 CSA 177.0 Port may have Pumping-Choke with HP Loss ( too fast FPS )
311 2.14860 CSA 187.8 Highest useable Port velocity ( good TQ + HP • possible HP loss )
300 2.22738 CSA 194.7 Smallest Port CSA ( Hi Velocity FPS • very good TQ and HP )
285 2.34461 CSA 204.9 Recommended Port CSA ( very good TQ and HP combination )
260 2.57006 CSA 224.6 Recommended average Intake Port CSA (very good TQ and HP)
250 2.67286 CSA 233.6 Largest recommended average Intake Port CSA ( good HP )
240 2.78423 CSA 243.3 Largest recommended average Intake Port CSA (less Peak TQ)
235 2.84347 CSA 248.5 Largest recommended Intake Port Gasket Entry area CSA
225 2.96985 CSA 259.5 Largest Intake Port Gasket Entry CSA ( Slow FPS )
215 3.10798 CSA 271.6 Possible Torque Loss with Reversion ( Slow FPS )
210 3.18198 CSA 278.1 Torque Loss + Reversion possibility ( too slow FPS )
200 3.34108 CSA 292.0 Torque Loss + Reversion possibility ( too slow FPS )
304.7 2.19319 CSA 191.7 278.4230 CFM = Maximum Intake Port Flow at 0.641992 Valve Lift
Exhaust Exhaust Average Maximum Exhaust Port Flow @28 inches = 221.6675 CFM at 0.631423 Valve Lift
Velocity Cross-Sectional Exhaust Port 6000 RPM ( RPM Range = 4000 to 6500 RPM )
FPS Area sq.inch Volume CC's ----- Description --------------------------------
435 1.22299 CSA 58.1 Port and Throat Area have Pumping-Choke (too fast FPS • HP Loss)
380 1.40001 CSA 66.5 Port may have Pumping-Choke with HP Loss ( too fast FPS )
350 1.52001 CSA 72.2 Highest useable Port velocity ( possible HP loss • too fast FPS )
330 1.61213 CSA 76.6 Highest useable Port velocity ( good TQ + HP • possible HP loss )
311 1.71062 CSA 81.3 Highest useable Port velocity ( very good TQ and HP combination )
300 1.77334 CSA 84.3 Recommended Port CSA ( very good TQ and HP combination )
285 1.86667 CSA 88.7 Recommended average Exhaust Port CSA (very good TQ and HP)
265 2.00756 CSA 95.4 Recommended average Exhaust Port gasket area at exit
240 2.21668 CSA 105.3 Recommended largest Exhaust Port gasket area at exit
225 2.36445 CSA 112.4 Largest Exhaust Port Exit gasket area at exit (Slow FPS)
210 2.53334 CSA 120.4 Largest Exhaust Port Exit gasket area at exit (Slow FPS)
190 2.80001 CSA 133.1 Torque Loss + Reversion + Scavenging loss (too slow FPS)
180 2.95557 CSA 140.5 Torque Loss + Reversion + Scavenging loss (too slow FPS)
363.2 1.46469 CSA 69.6 221.6675 CFM = Maximum Exhaust Port Flow at 0.631423 Valve Lift
This was based on a very conservative total intake flow number.... If Charlie is as CDO (OCD to the point of being offended the letters arent in alphabetical order) as I think he is, we should be better than this.
hope this doesn't screw up the thread, and if it does, please delete.
I've always wondered why the 5.0 fox stang seemed so rpm friendly compared to the tpi. Was it port shape, length, cam, ecm, firing order, small cubes, short stroke, port velocity, intake port layout or what? The way the air comes in the upper intake, hits the back plenum wall and has all the long and short 180s, you'd think it wouldn't be as happy. But a simple mild cam swap and those would bang 6300 rpm with ease. Even the 351/408 combos woud rpm with ease.
Again, i don't want to stray away from the tpi tech (so delete if needed) but I've always wondered if there was a possible answer in the ford setp that Is being missed by the tpi crowd?
hope this doesn't screw up the thread, and if it does, please delete.
I've always wondered why the 5.0 fox stang seemed so rpm friendly compared to the tpi. Was it port shape, length, cam, ecm, firing order, small cubes, short stroke, port velocity, intake port layout or what? The way the air comes in the upper intake, hits the back plenum wall and has all the long and short 180s, you'd think it wouldn't be as happy. But a simple mild cam swap and those would bang 6300 rpm with ease. Even the 351/408 combos woud rpm with ease.
Again, i don't want to stray away from the tpi tech (so delete if needed) but I've always wondered if there was a possible answer in the ford setp that Is being missed by the tpi crowd?
No idea. Ive had several but never looked into the intake flow stuff like this. If I had to guess I would say the 5.0's were just lighter and tuned for a higher RPM peak which made them favorable for guys on the street.
hope this doesn't screw up the thread, and if it does, please delete.
I've always wondered why the 5.0 fox stang seemed so rpm friendly compared to the tpi. Was it port shape, length, cam, ecm, firing order, small cubes, short stroke, port velocity, intake port layout or what?
Yes. My good friend and I were talking about this yesterday. The late '80's 5.0 has slightly shorter runners than a TPI, a 210/210 cam, and tubular exhaust manifolds w/dual exhaust and dual cats. Those elements are what allow it to rev higher and feel the way that it feels. The bigger bore probably doesn't help much b/c the head flow is terrible.
The exhaust manifolds and exhaust really kill the TPI (compared to the Ford). Richard Holdner tested a 5.0 "HO" TPI and a 5.0 HO Ford and on the dyno (read, no F-bod exhaust + dyno headers), the TPI did 267 (gross) hp at 4700 RPM, compared to the Ford 5.0 HP that came in on his dyno, at 261 (gross) hp at 5100 - 5200. Less power, but 500ish more RPM...
On the dyno, exhaust is "even", so that variable is eliminated. Runner length, cam and exhaust helps the Ford rev better/higher, IMO.
Last edited by Tom 400 CFI; 04-18-2024 at 09:15 AM.
Not to mention that sweet sound those puppies make. I love my Camaro but NOTHING sounds like Foxbody with 2 chamber flowmasters and an H pipe. Good stuff!
The exhaust manifolds and exhaust really kill the TPI (compared to the Ford). Richard Holdner tested a 5.0 "HO" TPI and a 5.0 HO Ford and on the dyno (read, no F-bod exhaust + dyno headers), the TPI did 267 (gross) hp at 4700 RPM, compared to the Ford 5.0 HP that came in on his dyno, at 261 (gross) hp at 5100 - 5200. Less power, but 500ish more RPM...
On the one hand, I know you mean "Gross" as in "without deduction or other contributions", but on the other, it is way more entertaining to read it in the "very obvious and unacceptable" definition.
Sorry to side track, this is all well above my experience and I'm enjoying the info!
hope this doesn't screw up the thread, and if it does, please delete.
I've always wondered why the 5.0 fox stang seemed so rpm friendly compared to the tpi. Was it port shape, length, cam, ecm, firing order, small cubes, short stroke, port velocity, intake port layout or what? The way the air comes in the upper intake, hits the back plenum wall and has all the long and short 180s, you'd think it wouldn't be as happy. But a simple mild cam swap and those would bang 6300 rpm with ease. Even the 351/408 combos woud rpm with ease.
Again, i don't want to stray away from the tpi tech (so delete if needed) but I've always wondered if there was a possible answer in the ford setp that Is being missed by the tpi crowd?
Because of the lower base its like a tunnel ram, Ive seen so many say that the TPI is inferior because of the 180 curve in the runners but are quite about other similar intakes, IMO the lower TPI base has very bad angles
mustang intake runners end with a open plenum this is why I believe you shouldn't cut back the divider on TPI runners because now the runner inlet will be facing the runner wall instead of the plenum
the total runner length of the 80s mustang intake is actually longer than the TPI
On the one hand, I know you mean "Gross" as in "without deduction or other contributions", but on the other, it is way more entertaining to read it in the "very obvious and unacceptable" definition.
Sorry to side track, this is all well above my experience and I'm enjoying the info!
Makes sense doesnt it? The air has to have a speed associated with a cfm number. Without actual movement of the air, CFM will be 0 as the pressure will be atmospheric. With a pressure drop, you can control it via CSA size and that will ensure you flow as much as the area allows without causing pumping losses or flow too less where the CFM wont wont be maximized and the piston demand isnt maximized either as a result.
This actually shows I need a 366 cube engine for max benefit but with the bends and turns in the TPI system, Im willing to bet the 350 will do just fine. I can also get more power depending on how much better the aftermarket stuff does ported and this gives Charlie a blueprint to go by. 2.08" CSA. 300FPS. 20".
I wonder if Mike Jones has ever used any asymmetrical lobes to open fast and close slow using smaller durations? Id guess yes. This would allow the valve closing to be delayed some after BDC to allow more inertia of air to be rammed into the cylinder. I spoke about this earlier and from what I understand, the possibility of have reversion at lower RPM like cruising may be a possibility. Basically what happens is that small amount of time at TDC on the exhaust stroke, the intake valve is also open at overlap beginning the intake stroke and exhaust cylinder pressures MAY be more than the intake pressure causing exhaust to go into the intake and delay cylinder filling. This would effect things like idle and cruise O2 readings, part throttle and off idle etc. Its something I need to look into more to get an understanding of. From what I see now, by using the fastest velocity possible by using the smallest CSA usable for good power and tq, the pressure in the intake should be good enough to prevent this.
mustang intake runners end with a open plenum this is why I believe you shouldn't cut back the divider on TPI runners because now the runner inlet will be facing the runner wall instead of the plenum
the total runner length of the 80s mustang intake is actually longer than the TPI
Yes. That IS the big problem. Intake runner entry into the head. It aims at the roof where a better intake will aim at the valve. If you look on the last video, Charlie is experimenting with curving the roof area in the intake to "blow" lower in the head. Of course by doing that, your CSA goes out the window and I am not sure it would be any better.
I wonder if Mike Jones has ever used any asymmetrical lobes to open fast and close slow using smaller durations?
I would suspect that this would be challenging to benefit from dramatically based solely on geometry. Since the Ramp should enter the nose and the heel of the cam lobe tangentially, your only metric for variation is the radius used on the ramp. Decreasing the radius will necessarily increase the total duration by infringing on the heel further, or reduce the lift by infringing on the nose more.
I could be absolutely wrong, just sharing my thoughts.
-edit-
Go figure, it took 30 whole seconds of googling to find that these DO exist.
I'll go ahead and make myself MORE vulnerable to being wrong by suggesting that this would only work with roller lifters, as flat tappet lifters would move the point of contact around across the duration of the cam.
Last edited by codyman125; 04-18-2024 at 10:44 AM.
Reason: Added info
---- Induction System Tuned Lengths ---- ( * Open-End Tube = both Odd and Even Numbered Harmonics )
Harmonic Total Intake Manifold Air / Fuel Ratio = 13.20000:1 BSFC = 0.6469 LbsHour/HP
Wave Induction Port Runner ( Induction System operating RPM Range from 4000 to 6500 RPM )
Number Length Length Length ------ Description --------------------------------------------
1st 40.3309 = 5.3330 + 34.9979 typically Induction Length too long to fit or use effectively
2nd 20.1654 = 5.3330 + 14.8324 creates the highest Peak Torque, but may lose higher RPM HP
3rd 13.4436 = 5.3330 + 8.1106 ProStock, Comp Eliminator, etc. best Peak TQ and Peak HP Combo
4th 10.0827 = 5.3330 + 4.7497 Single-Plane Manifold, slightly less Torque than 3rd Harmonic
5th 8.0662 = 5.3330 + 2.7332 Peak Torque is substantially reduced, even though Tuned Length
That's the information I was looking for.
For ****** and giggles, I ran that length through DV's Torque Master. Engine is modeled after my own (similar CID, more CFM than the Darts, lowered the CR to 10:1). LPE 219 cam with 270/270 but on a 108.
20" induction length using 2nd wave reflection.
22" induction length using 2md wave reflection
IMHO. I'd say the greatest HP output will be achieved when the peak HP RPM resulting from the cam seat timing is reconciled with the tuning RPM HP peak from the induction. Peak is the operative word there.
FTR: For those not familiar with DV's software, the white boxes are data entry points, any yellow box is a result. The two white boxes referencing induction are results also although they don't change the where the HP and TQ peaks results are or the output.
That's the information I was looking for.
For ****** and giggles, I ran that length through DV's Torque Master. Engine is modeled after my own (similar CID, more CFM than the Darts, lowered the CR to 10:1). LPE 219 cam with 270/270 but on a 108.
20" induction length using 2nd wave reflection.
22" induction length using 2md wave reflection
IMHO. I'd say the greatest HP output will be achieved when the peak HP RPM resulting from the cam seat timing is reconciled with the tuning RPM HP peak from the induction. Peak is the operative word there.
FTR: For those not familiar with DV's software, the white boxes are data entry points, any yellow box is a result. The two white boxes referencing induction are results also although they don't change the where the HP and TQ peaks results are or the output.
Yours says 428hp? Mine says 438! lol. Anything over 385 and I consider this a win. 385hp with nice drivability, running A/C and enough power to run mid 12's and burn the tires from 40mph? Psh.. See ya Mr. 400Z. 425hp is even better and it looks STOCK. Daydreaming! Itll probably go into sonic choke and make chitty chitty bang bang noises right before the bumper falls off.
Yours says 428hp? Mine says 438! lol. Anything over 385 and I consider this a win. 385hp with nice drivability, running A/C and enough power to run mid 12's and burn the tires from 40mph? Psh.. See ya Mr. 400Z. 425hp is even better and it looks STOCK. Daydreaming! Itll probably go into sonic choke and make chitty chitty bang bang noises right before the bumper falls off.
Look though at where the HP peak is. Regardless of the induction, it's predicting peak at 5300! And at the RPM, estimated minimum port flow is 219 CFM. IIRC, isn't that more or less what you've managed with head and intake tested as an assembly?
For the record, for my project, I spec'd peak HP RPM at 6000 and some left over to carry to 6500. This is a 4000 stall converter deal (with lockup) so the RPM band is narrower than that for street car. That said, still very streetable.
With those details in place both Jones and Vizard offered 280° seat to seat on the intake. Both on a 108 LSA and 104 ICL.
I did more work on the stock base and going through Dart 007's that flow 277 it flowed 270 last night. I will check air speeds tonight if I can. Thanks
I did more work on the stock base and going through Dart 007's that flow 277 it flowed 270 last night. I will check air speeds tonight if I can. Thanks
Welcome to TGO Mr. S.
I, for one, am looking forward to your contributions!
I did more work on the stock base and going through Dart 007's that flow 277 it flowed 270 last night. I will check air speeds tonight if I can. Thanks
Welcome to TGO Charlie.
I just packaged it all and loaded it. I sent you a text.
Look though at where the HP peak is. Regardless of the induction, it's predicting peak at 5300! And at the RPM, estimated minimum port flow is 219 CFM. IIRC, isn't that more or less what you've managed with head and intake tested as an assembly?
For the record, for my project, I spec'd peak HP RPM at 6000 and some left over to carry to 6500. This is a 4000 stall converter deal (with lockup) so the RPM band is narrower than that for street car. That said, still very streetable.
With those details in place both Jones and Vizard offered 280° seat to seat on the intake. Both on a 108 LSA and 104 ICL.
Thats ok. Im looking for maximizing the average power using the biggest runners available. If it holds the power after that and makes some extra due to the airspeed flowing more air we did good.
I like Erland's input at ST. He's brought the wave tuning into the picture with his comments on 2nd or 3rd reflections in the TPI intake.
That PipeMax sheet you posted might be an interesting point of discussion over there as well.
I'm hesitant to bring any DV inspired discussions there though as his detractors will just crush the thread.
I like Erland's input at ST. He's brought the wave tuning into the picture with his comments on 2nd or 3rd reflections in the TPI intake.
That PipeMax sheet you posted might be an interesting point of discussion over there as well.
I'm hesitant to bring any DV inspired discussions there though as his detractors will just crush the thread.
Id bring it anyway. He's told Charlie to keep him in the loop and gave us some pointers.... If David's wave tuning says its going to peak at 53XX then it probably will be close to that...
You know, you should run Jim Halls 355 on there just to see what it says..
355 TPI 9.6:1
ASM runners
Ported plenum
52 or 58mm tb
AFR 190 Vortec heads
ported SDPC vortec tpi base
Lil Chubs cam 220-224 .500 .500 110 LSA
pipemax couldn’t correlate this or Holdeners tests.. So I use it as more of a guide than anything for this thread.
I did get DynoSim6 to work… but I had to kill the Tb size to 385cfm lol
after that it was within 5-8hp all down the RPM range. FWIW
DV's Torque Master is about cam selection. So in that regard it's not a simulation tool.
You can manipulate some of the data points to get it's results to correlate with a real world example though.
Case in point is TM says my 357 will peak at 5850 with 280° intake duration. Jones suggests his grind (280°) will peak closer to 6200. DynoSim shows table top flat from 6000-6500.
I replied to Charlie's ST post about 2nd wave reflection and the RPM where that peak would fall in. Quoted Erland in that too. I'll see where it goes.
These are a couple of excellent threads. I'd hate to mess it up with hate motivated inputs although I'm am aware that Charlie and David are collaborators on a few projects. Not to mention Charlie being a DV "student / instructor" on some level.
As for Hall's 355. Are there advertised cam specs out there somewhere? Lil Chub isn't much to go on! 220/224 is probably something like 270/276 adv.?
Originally Posted by MrIROBZ
.. If David's wave tuning says its going to peak at 53XX then it probably will be close to that...
That's thing about TM that's a little odd.
It'll give an estimated HP and TQ RPM peak for a given cam. Then off to the side, there's a little info regarding the induction length. It provides an RPM where HP and TQ have a bump in output. But...it isn't reflected in the RPM points suggested via the cam itself. And we know that a single plane intake with "X" cam will peak differently than an identical package with a TPI. Something I would, if I could, discuss with the author. But he still hasn't gotten back to me through his email request for a conversation on another ST post that I made.
What I did was use known good examples and changed minor details to see what that reflected. I think this is the ONLY way to sim an engine. From scratch there are too many variables. Start out with something you know you can correlate with a lot of data and work off that.
I wish Allen (1989TransAmGTA) or Dyno Don would chime in. They are probably bored with this post knowing it wont make anymore RPM or HP than they did though.
Ultimately, I think this thread could be useful for future third gen TPI owners who are restoring their cars and want to add some power when doing the engine. Thats what the other classic car owners do now. Itll look bone stock but make another 50-100hp. Pure Stock Drag Racing class is at an all time high right now too. Its like Super Stock but for matching numbers cars. Ever seen a Chevelle with a 396 run a 10 on stock parts? Its pretty awesome what theyre doing.
I'll certainly agree that modelling an engine can have a whole different approach if there's a live specimen to base off of.
That this thread is more or less third gen specific makes it even better for the very reasons you point out.
I think this too is why QwkTrip was quick (no pun intended) to jump in and restore order. And I'm glad he did. Like Kevin's/Dyno Don's/Allen's thread from years back, it's now part of the historical record and should anyone want to venture into the TPI darkness, there are a couple of guiding lights.
The pure stock drags are something else. I also like the F.A.S.T. racing class. If I could I'd apply some of their technology into the getting the long time mothballed 502 BBC/TKO stick shifted Trans Am back to the track. Hope was given up it for it to be a track star when hooking it up was all but impossible with what we knew at the time. That being 20 years ago. It's still a beast but there's a lot of rear wheel steer going on!
Kinda off topic but I got a few other things done that I wanted to do.
I like SQ over SPL, so I put an entire Focal/JL system in the car and swapped some brake parts to handle more power.
The head unit is a Kenwood DMX958XR.
Amp is a JL RD900/5
[QUOTE=MrIROBZ;6530555]Kinda off topic but I got a few other things done that I wanted to do.
I like SQ over SPL, so I put an entire Focal/JL system in the car and swapped some brake parts to handle more power.
The head unit is a Kenwood DMX958XR.
Amp is a JL RD900/5
[What Focals did you use in the dash? Did you have to do any cutting of the AC ducts?
04-15-2024, 09:24 PM
