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*The first place I dyno'd the Kart at, was a place called TurboLabs. They're down in Provo...I recall that I went there b/c they were available, and cheap @~$90 bux. They used a dynojet, too. That place is owned/operated by two "kids". I call them kids...they're probably in their mid 20's? Props to them for having the ambition to open a shop, buy the tools etc. and make a go of it. Anyway, there were two funny things about that visit.
First, Neither of the kids knew how to hook up the Dyno inputs to the Kart, since it didn't have an OBD II connector. I had to show them how to use the inductive p/u for the tach signal...they'd never used it before and had no idea what it was/for!
Second, I told them to start the pull at 500 RPM...as I've requested for each and every pull. They didn't like that. "You're going to blow a connecting rod!", they told me. Blow a connecting rod, lol. I assured them that it would not blow anything, by starting the pull that low. They didn't believe me. After much assurance and convincing, they finally, begrudgingly agreed to start the pull down low. They missed 500 RPM (as most dyno ops seem to do, in my experience), but they still captured a pretty low number that's good enough. No rods blew.
Last night, I was looking at a dyno sheet that I have from back in the day when I had my '06, C6, with the (stock) LS2 engine and I had a little epiphany. I've never really thought too much about it in the past but I was looking at the curve, and I was thinking that something didn't look "right". WTF was it? The tq part of the curve looked WAY off, to me. It looked too low...way too low. How could it be that low!? Recently I've become accustomed to the Tq numbers that the Kart's been making, in the 370's, and here I am, looking at a 400hp engine that's making ONLY 355ish tq!? How in the world is a larger cube, higher compression, better tuned/ECM'd engine making less tq?? Well, it did. It's pretty surprising to me that the LS2 doesn't do more peak tq, w/all of the advancements, size and compression advantages that it has. It makes it all the more impressive (to me) that with exhaust and some intake(s), this sludged up, ****-box 350 is doing over 400 crank tq.
I have had that same debate numerous times with dyno operators wanting to start a pull at ~1,000 rpm. I have added 20+ ft/lbs in the 1,000-2,000 range on several setups properly dialing in that area of the tune most tuners ignore. Optimizing the torque output there helps fuel economy by being able to stay in a taller gear more easily.
I also pointed out to you in the 87 LG4 305 post a while back that the mighty LS1 made all of ~310 rwtq at peak in stock form and did not break 300 rwtq until nearly 3,500 rpm. The LS engines all build their peak torque around 4K as well. None of them really have a lot of grunt under ~3,500 rpm. I tuned a LQ9 6.0L/4L65E truck with a fairly hot tune a while back and it barely cracked 300 wtq. it was not torque management holding it back either, it made what it made. The LQ9 only made like 380 tq at the flywheel on the factory premium fuel only tuning and GM did not leave much to gain in tuning it. The polar opposite of my TBI 350 that with some headers, exhaust and tuning that had already peaked ~308 tq before 3,000 rpm and was already dropping off when a pull was started at 3K.
Those 113 aluminum heads with their ~163cc high velocity ports are very good for torque production. The TPI base also has a substantial runner length in the base itself. You mentioned runner length not having a huge effect between these runner setups, however bolting a shorter runner onto the TPI base does not come anywhere close to the short runner intakes like the LT1, Mini-Ram or Ramjet intakes. The Mini Ram took a heavy torque hit from its overly short runners. A substantial chunk of the overall intake runner length is in the TPI base itself on the other setups. I had siamesed SLPs on my 383 Vortec TPI, it made great torque and made peak HP at ~5,500. The Crossfire and cross ram style Vortec truck/marine manifold have about the same length runners as the TPI base on its own and still build decent torque. My L31 marine manifold on my latest 383 also peaks around 5,600 rpm with a 218/228 @ 0.050 cam with a torque peak at 3,400 rpm.
Gen 1 SBC can make impressive low-speed torque compared to the newer LS and LT engines. The HP and TQ curves of GMs L31 marine 350 has always impressed me at how flat the curve is. The Ramjet 350 is the same long block with 1.6 rockers added and the Ramjet intake manifold. The Ramjet curve shifts but still makes equal torque, just later in the curve. The L31 marine engine makes more torque under 3,000 rpm than the LY6 6.0L with rectangle ports and VVT does. It also blows away the L83 5.3L with ease through most of the power curve, it takes the DI 5.3L that has incredible flowing heads, VVT and 11:1 compression its peak torque at 4,000 rpm before it makes as much torque as the L31 at 2,500 rpm. I find that impressive given the L31 Marine/Ramjet engines have an ultra thick 0.053" thick head gasket that drops them to 9.1:1, they use a 196 @ 0.050 cam and the Mexican 062 Vortecs that only flow 210-215cfm @ 0.450 peak.
This was the Ramjet 350 dyno test, it is not an apples-to-apples comparison with the Marine test above though. It had long tube headers rather than the marine manifolds with catalytic converters and was tested with an electric water pump where the marine engine was tested with full accessories including the flame arrestor. Either way you want to look at it the old 350 makes surprising torque numbers.
Years ago, I tuned a 3rd gen local to me that had a L31 crate engine that was upgraded to the LT4 Hotcam package with 1.6 roller rockers and had the Ramjet manifold kit on it. That car would absolutely fly for what it was.This might particularly interest Tom because of his curiosity as to just how far the MAF based system can tolerate changes. It was put together and running with the STOCK MAF system and stock eprom chip. When I got my hands on it the base timing was a bit low and the idle was a bit lean. I bumped the timing, adjusted the TPS, and found a weak fuel pump. After the pump change it required minimal tuning to have the car running well. I did have to remap the timing advance a bit to work with the Vortec heads better, but drivability wise it was great as it was. At WOT I did have to lean heavily into the PE multiplier because of the 255 gm/sec airflow limit in the ECM to get the thing enough fuel to drink. I also changed the injector data to work with the Ramjets 24 lb/hr injectors. That setup was right on the edge of needing more than 24 lb/hr injectors as it was making ~425 hp at the crankshaft. That car really needed a larger MAF tube, 28 lb/hr LT4 injectors and a tune scaled to work with the resulting MAF change. The other option would have been larger injectors and either the Austrailian $12P MAP speed density code for their 808 ECM that runs in the 165 converting it to MAP or a 7730 MAP ECM.
Im still running a stock tune in my 89 formula 350. It's a 400 plus ci sbc, solid roller w/.750 lift, 245 afr heads and miniram. 11.5/1 compression 24lbs injs. Infact, its been like this for 15yrs atleast. Gets 22mpg. Could it be better with bigger injs/maf/tune, yes but I'm not a tuner.
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^Love it^ Shows what CAN be done, which I think is important for those who can't/don't want to tune, then get "stuck" not doing mods b/c they've been led to believe that you need a tune. Some mods you may, but many can be worked around and it can be good enough.
Update; I said that I wasn't going to buy anymore intakes for this test....if people wanted to send me some, I'll keep spinning the dyno and posting the results.
Buuut....I couldn't help myself, and the price was really, good, so today I bought this, which will be intake #7 (after TTops350's intake) on the dyno.
Last edited by Tom 400 CFI; 10-22-2023 at 09:27 PM.
Update; I said that I wasn't going to buy anymore intakes for this test....if people wanted to send me some, I'll keep spinning the dyno and posting the results.
Buuut....I couldn't help myself, and the price was really, good, so today I bought this, which will be intake #7 (after TTops350's intake) on the dyno.
I have a a knock off Proflow 7137 with the regular SBC head intake pattern and a 92mm TB that could be tested if anyone is interested in that test. That being said hooking up a throttle cable and TPS might be more involved than you want to mess with.
I'm interested. That'd be a good test. Although it didn't exist when TTTT article was written, that intake is one of the "TPI" options that is mostly a bolt-on, these days. Also, I'm still looking for three more intake options to get to "10", so yours could legitimately fill one of those slots, IMO.
No way would it happen until next summer....I'll by LUCKY to be able to get TTop350's done this fall. Can you take a pic of the TB so that I could see how the TPS is supposed to mount? Could I used the "LS" TPS and simply make a connector/jumper that allows my harness to connect to that sensor? I think those sensors are 4 wire?
Last edited by Tom 400 CFI; 10-23-2023 at 12:59 PM.
I'm interested. That'd be a good test. Although it didn't exist when TTTT article was written, that intake is one of the "TPI" options that is mostly a bolt-on, these days. Also, I'm still looking for three more intake options to get to "10", so yours could legitimately fill one of those slots, IMO.
No way would it happen until next summer....I'll by LUCKY to be able to get TTop350's done this fall. Can you take a pic of the TB so that I could see how the TPS is supposed to mount? Could I used the "LS" TPS and simply make a connector/jumper that allows my harness to connect to that sensor? I think those sensors are 4 wire?
It is just a later style TPI, LT1, Vortec, LS1 style 3 pin connector TPS. It has a LS style 4 pin IAC as well.
The manifold is not going anywhere. I have plans to use it someday on the 1980 Z/28. I am going to touch up the minimal casting flash leaving the ports stock, port match the 92mm TB to the 90mm opening and grind the TB flange to fit the mounting bolts anyway. The chinese cloned the ProFlow exactly down to its Ford TB mounting bolt pattern. A problem the real Proflow also has when you attempt to put a 4 bolt LS throttle body on it. It will be a while before I get to that anyway. I feel like it will likely perform similarly to the HSR and possibly slightly outperform it given the runners are not as restricted as the HSR where the go into kind of a tree trunk design on the HSR. I bet this manifold has 7,000 rpm potential on a properly built long block. Doubt it would be a hot setup for a stock L98 kind of like the HSR loses a big chunk of torque as well, but it would be interesting to have as a comparison since it is an obtainable replacement today where many of the TPI based setups like the SR or T-Ram are not easy or cheap to come by.
Whoa. lot has happened in here in the last few days congrats on the Stealthram purchase that's the intake I'm curious of since its been on my personal car for a few years now, I'm curious to see how much if any torque it losses compared to the Superram. I have since modified mine they sell spacers for it I have a 1/2 on there and I radiused and air foiled the top of the spacer stock the Stealthram has a big flat spot. I will soon be removing the Stealthram in favor of another modified tunnel ram, recently I've flowed a stock Steathram and wasn't impressed it flowed around 230-240 at .400-500 lift and only got 260 at 1 inch this was with no box and a clay radius, the ports on the Weiand tunnel rams for SBC are small compared to other SBC tunnel rams. Also there was a rumor I read on here that Holley are going to release another version of it and stop selling it soon
Here is a pic of a simple mod that can be done to the Stealthram its similar to the airfoil on the throttlebody
Whoa. lot has happened in here in the last few days congrats on the Stealthram purchase that's the intake I'm curious of since its been on my personal car for a few years now, I'm curious to see how much if any torque it losses compared to the Superram. I have since modified mine they sell spacers for it I have a 1/2 on there and i radiused and air foiled the top of the spacer stock the Stealthram has a big flat spot. I will soon be removing the Stealthram in favor of another modified tunnel ram, recently I've flowed a stock Steathram and wasn't impressed it flowed around 230-240 at .400-500 lift and only got 260 at 1 inch this was with no box and a clay radius, the ports on the Weiand tunnel rams for SBC are small compared to other SBC tunnel rams. Also there was a rumor I read on here that Holley are going to release another version of it and stop selling it soon
Here is a pic of a simple mod that can be done to the Stealthram its similar to the airfoil on the throttlebody
My guess is it is 30-40 ft/lbs down at peak on a Super Ram. I had a buddy put one on his car years ago and took me for a test ride in it. He was so impressed that it would rev out to 5,500 rpm. That being said the car felt noticeably slower. How much of that was placebo based off the loss of the normal TPI midrange feel I am not sure of. That being said the car was slower at the track and he ripped the EFI off the car and put a single plane and a 750 holley on it not long after. It proceeded to run even slower, he got fed up with the way it drove on the street and sold it. I feel like that actually happened a lot with these cars when guys hacked a carb in place of the TPI. He bought a cammed LS1 with his parents money and then proceeded to talk smack on a third gen forever after. I have not talked with the guy in years but he is probably still out there talking up his cammed LS1 that he probably never got out of the 13s in. He had a 6spd and was not a driver at all.
My guess is it is 30-40 ft/lbs down at peak on a Super Ram. I had a buddy put one on his car years ago and took me for a test ride in it. He was so impressed that it would rev out to 5,500 rpm. That being said the car felt noticeably slower. How much of that was placebo based off the loss of the normal TPI midrange feel I am not sure of. That being said the car was slower at the track and he ripped the EFI off the car and put a single plane and a 750 holley on it not long after. It proceeded to run even slower, he got fed up with the way it drove on the street and sold it. I feel like that actually happened a lot with these cars when guys hacked a carb in place of the TPI. He bought a cammed LS1 with his parents money and then proceeded to talk smack on a third gen forever after. I have not talked with the guy in years but he is probably still out there talking up his cammed LS1 that he probably never got out of the 13s in. He had a 6spd and was not a driver at all.
His Stealthram was slower than what previous intake? stock tpi?
With the shorter runner intake tuning is required to get the most out of it but yeah they lose down low but on the positive side its easier to hook and 60ft times are better and easier to achieve
After seeing the Stealthram side by side with other SBC tunnel rams I was shocked how small the ports where on the Stealthram
After seeing the Stealthram side by side with other SBC tunnel rams I was shocked how small the ports where on the Stealthram
Me too, when/after buying this one, I looked down the thing and wondered how they've done so well?? In the original TTTT test, the HSR was basically tied for top HP with the MR (4 hp diff), and did so w/in 100 RPM of the MR. Weird. I'm looking forward to see how it ranks on this engine. I guess I have low expectations, but I did for the AS&M runners and I got schooled by those.
His Stealthram was slower than what previous intake? stock tpi?
With the shorter runner intake tuning is required to get the most out of it but yeah they lose down low but on the positive side its easier to hook and 60ft times are better and easier to achieve
After seeing the Stealthram side by side with other SBC tunnel rams I was shocked how small the ports where on the Stealthram
It was slower than the stock TPI. I have made ~300 whp several times with basically stock TPI intakes. They are tough to beat in a stock gear and stock converter automatic car.
Smaller runners are not a great feature unless you are looking for economy. Look at how poorly the SP2P manifolds ran. They were ok on a K10 pickup pulling a boat to the lake but junk for actual performance.
Me too, when/after buying this one, I looked down the thing and wondered how they've done so well?? In the original TTTT test, the HSR was basically tied for top HP with the MR (4 hp diff), and did so w/in 100 RPM of the MR. Weird. I'm looking forward to see how it ranks on this engine. I guess I have low expectations, but I did for the AS&M runners and I got schooled by those.
Weren't AS&M runners the ones used on the Something New Something Old TPI 355 build that made close to 420 hp and 500 ft/lbs?
After dyno testing engines with heads flowed on their flow benches, SuperFlow came up with a number of approximately 2.05 HP per CFM of flow.
If we take the peak horsepower numbers from the TTT article and divide them by 2.05 we can see "virtual" cfm's for the different intakes and the cylinder head used.
We can also see that as the top few intakes approach the head flow cfm's they start to bunch up.
At this point we are testing the cylinder heads horsepower limit and not the intake manifolds.
The Mini Ram and Holley both flow up over 300 cfm.
Same thing is happening with Tom's tests.
The stock L98 head flows about 184 cfm @ 0.431 lift (depending on the flow test you reference).
Looking back at the chart above, all these manifolds flow more than that, so the head is limiting the peak power in these tests.
Then why are they different at all?
Even though the intakes all flow more than the head, they still create a loss when put in series with the head, better flowing intake equals less resistance less loss.
The intake manifold's inertia ramming and wave tuning create 2 to 6 psi at their peak tuning rpm.
Like a narrow band supercharger that pushes air past the head restriction.
Where their peak tuning rpm lands is what really separates these intakes.
The Mini Ram flows the most but doesn't develop any boost down low, that's why it does so poorly on this stock L98.
The Super Ram has the next highest flow potential but lower boost, it wins the horse power race but is down on torque.
The TRam, Siamese and AS&M Long Tubes are so close in flow potential, it comes down to the best boost curve match for the stock L98.
It wouldn't surprise me if the Long Tube AS&M runners gave the best horsepower and torque (stock L98) because they flow as well as the Siamese runners but should make a lot more torque.
EAPro simulation of the intake tuning pressures for these manifolds on a STOCK L98.
Used the best dimensions I have for the different intakes ... may not be exact.
Added in the AS&M (TPIS) long tubes.
As usual, Awesome posts and assessment of what's happeing here, with these different intakes. Thanks for weighing in.....I'm so glad that you're participating in this thread, over here. Thank you!
Originally Posted by Fast355
It was slower than the stock TPI.
Are saying that someone put an HSR on a stock TPI car (very similar to what I will be doing)....and the car made less power and went slower? That is incredibly hard to believe, so looking to clarify, here b/c that's what it seems like you're saying. (?)
Originally Posted by Fast355
Weren't AS&M runners the ones used on the Something New Something Old TPI 355 build that made close to 420 hp and 500 ft/lbs?
I have no idea. I don't know anything about a "sump'n/sump'n 355 build". What I do know is that the AS&M runners on a big base did ~460hp, crank/gross on the TTTT 383, which was firmly "mid pack" and ~40hp off of the highest performing intake in that test, the MR. The same runners did 280 RWHP on the Kart, putting them in 2nd best, out of 5 intakes, so far....9 hp off the best so far.
Last edited by Tom 400 CFI; 10-26-2023 at 10:38 AM.
As usual, Awesome posts and assessment of what's happeing here, with these different intakes. Thanks for weighing in.....I'm so glad that you're participating in this thread, over here. Thank you!
Are saying that someone put an HSR on a stock TPI car (very similar to what I will be doing)....and the car made less power and went slower? That is incredibly hard to believe, so looking to clarify, here b/c that's what it seems like you're saying. (?)
I have no idea. I don't know anything about a "sump'n/sump'n 355 build". What I do know is that the AS&M runners on a big base did ~460hp, crank/gross on the TTTT 383, which was firmly "mid pack" and ~40hp off of the highest performing intake in that test, the MR. The same runners did 280 RWHP on the Kart, putting them in 2nd best, out of 5 intakes, so far....9 hp off the best so far.
Just because the car went slower does not mean that peak power was lost. It is possible to gain peak power and still go slower. Remember the stock converter stalls like 1,500 rpm and the L98/Automatic cars usually had a 2.77 rear gear. Going off memory his car slowed down 1/2 second and of that it lost 0.2-0.3 in the 60' and that takes a lot of increased HP to overcome on the top-end. For reasons I do not fully understand, any time I have cut 0.1s off my 60', I have had 0.2 quicker ET on the big end. I am also talking 60' reductions without adding any power to the setup.
With a 2.77 gear the car is geared in a way that 1,000 rpm ~ 10 mph in 1st gear. If the thing loses torque under 3,000 the car has to be moving 30 mph before it even breaks even with stock.
Thanks Komet. It's definitely turned into a "team effort", which IMO, makes the whole thing so cool.
I wish it would progress more quickly, (if it were my only hobby/activity, it would!), but it's coming along. If we have an "Indian Summer/November", I can get TTop350's done this year too, but IDK how the weather will work out. Got 6" of snow this AM, at my house.
[QUOTE=Tom 400 CFI;6516069]Are saying that someone put an HSR on a stock TPI car (very similar to what I will be doing)....and the car made less power and went slower? That is incredibly hard to believe, so looking to clarify, here b/c that's what it seems like you're saying. (?)
I didn't catch whether the HSR was tuned after swapping from a TPI? If not, the PE fueling for the TPI would be really screwed up for a short-running intake. Swapping to a short runner from a long runner (to me) would be about the worst handicap for good results. On a TPI, the most PE fuel is delivered around 3600rpm. With a TPI, you could add that and more in the 4k, 4.4k, 4.8k, 5.2k....cells. With the TPI, they actually lean out cells above 4k rpms because the long runners starve the engine for air.
Going to BIGGER long runners would be OK...especially if you increase fueling (FP). Make it fatter everywhere (with larger tubes) and it should do pretty well. (Note the SR is still long enough to work).
BTW Tom, I pulled your corresponding CF thread up as an invite to post over there BEFORE SuperL98 told me you might not be posting there anymore? I sent an email but don't know if it went through? Will you return OR should someone (who, like you) is fascinated by TxTT copy your great testing for the CF to see?
Double BTW...Your Kart is looking way KOOL! I like what you've done to the frame and dash...and wing. I bet that thing is an even BIGGER blast with bigger nostrils! Good thing you have a stick to REALLY enjoy it! <wink, wink>
(Can't remember if someone has suggested it, but I hope an FFI gets you attention (on the dyno) one of these days. Personally, I think you might like it more than the HSR. That's assuming you get ANY kind of traction in the KART)
Great to hear from/see you. I'll speak to the 'Vette Forum briefly; I was banned for a month b/c of the "R autos sporty?" thread (funny that you should reference that one!). The ban ended 3 weeks ago, but I'm at odds contributing anything to that forum at this point; not because of the ban, specifically, (although that was annoying as I felt that it was a pretty typical "forum argument" that could have easily been moderated with a "Cut the crap, guys." from a mod), but mostly b/c of the way the moderator handled the whole thing, and reacted when questioned about it. It could have been managed a LOT better, IMO, and the way it was done, sent a message about how I'm valued by that forum....or at least, that mod. That message is, that I should commit my time to something/someplace else.
Right now, I'm not adding anything to that forum. I'd appreciate it if my contributions here, were not shared over there, for that forums benefit, at the moment please. Hopefully IBJason can smooth it out and I'll resume adding to that thread. We'll see. It will be a shame if it doesn't work out. I like most of the people over there, you included, a lot. I consider most of the C4 folk to be friends and I'd rather not have those connections broken. Sorry for the "**** Sandwich", there.
You're right about the tune with the short runner intakes. When I did the Mini Ram, I had to make more pulls and spend some time dicking around w/fuel pressure to get the AFR reasonable at the two peaks....to get max peak numbers. Same with timing. The TPI timing curve doesn't really work with the short runner curve. But we could work around that by adjusting base to get the right timing at the tq peak, then again at the hp peak.
I'm keen on trying the FFI, if someone feels like sharing one for a while. I'm not partial to any of these intakes....except maybe the SR now! Going into this whole thing, I WAS partial to the T-Ram. I'd built it way up in my head and I was pretty convinced that it would dominate the field, on a stock engine. I got "skooled" on that one!
Thanks for the props on the Kart. It's been a fun project to mess with, and it is a blast to drive....an "amusement park ride, that you control". This intake testing thing has turned out to be a LOT of fun for me, and the Kart has turned out to be a great platform to do it on due to the stock-ed-ness of it, and how easy it is to work on; it's got a built-in, mechanic's chair! And things like fuel line configuration etc. don't matter too much, so it has made swaps pretty easy.
Stay in touch! I'll PM you my email so we'll always be able to connect that way.
You're right about the tune with the short runner intakes. When I did the Mini Ram, I had to make more pulls and spend some time dicking around w/fuel pressure to get the AFR reasonable at the two peaks....to get max peak numbers. Same with timing. The TPI timing curve doesn't really work with the short runner curve. But we could work around that by adjusting base to get the right timing at the tq peak, then again at the hp peak.
I'm keen on trying the FFI, if someone feels like sharing one for a while. I'm not partial to any of these intakes....except maybe the SR now! Going into this whole thing, I WAS partial to the T-Ram. I'd built it way up in my head and I was pretty convinced that it would dominate the field, on a stock engine. I got "skooled" on that one!
-Tom
Adjusting the base? You talking about timing via dizzy position or something else? FWIW, I think your comparison is the single best approach to time/testing since (and even including) TXTT. Why? Because your demonstrating/isolating the intake -- and doing so with something less than max cam. Is that a fit-for-all-comparison? Maybe not anymore than the big *** cam used 15yrs ago but I know lots of readers really like it. Many, many owners do nothing more than "tune" by AFPR and/or timing adjustment via distributor position. Neither is ideal....but can be adequate.
Kinda.
I have to wonder what the comparison would be -- if complete tuning via chip alteration as I've done with my 383? If you "globally" alter fuel/timing, you gain something here and lose something there. Maximum results aren't what I'd bet on. I completely understand why the SLP was your "fav" and garnered your idealization. If tuned by chip, maybe it could be better? Same for the MR....leaner down low and richer up top? BUT, then again, the 113 heads aren't ported/designed for highest rpm performance.
No test is the test for the ages, but yours is definitely good. I have always thought the Superram is the best choice for 350's...which your test proved. Nowadays, I've decided the FFI could be even better. It's definitely at the top of my list these days. But then again, I'm not building a motor that'll rev to 7k - 8k rpms where short runners are probably the best/only option.
Everything has it's pluses and minuses. You are doing an absolute GREAT job letting us see where they are. My only regret is we all can't take turns FEELING them in a 2k# frame! DAMN! That has to be fun!!!
I'm really surprised at these numbers, especially at the rear wheels. The early 4th gen LT1 rated a 270 hp at the crank. And a set of good headers/exhaust, even on the Corvette, might show some impressive gains too. I had an 85 with the 4+3 and while that car was fun to drive it felt like the 230 hp was stretching it some. Superb effort on this series!
Thanks for the props, Tom3!
I have been very surprised by every test since the beginning, except for the MR. The very first test, box stock engine w/no air filter, and home made dual exhaust/no cats, optimized base timing and a 160 stat, it did 241 at the wheel! And this engine was no fine example of care and maintenance! Anyway, the rest of the intakes have really impressed me for the pretty massive gains, as a single bolt-on part. With the SR, 289 RWHP, that's got to be some where around 320 crank? (~10% drivetrain loss?). It's definitely surprising to me that a ratty old, uncared for TPI motor is easily doing over 300 (crank) with no tune, no valve covers off.....I certainly wasn't expecting that, when I started into this whole adventure.
Originally Posted by SuperZZ4
We can also see that as the top few intakes approach the head flow cfm's they start to bunch up.
At this point we are testing the cylinder heads horsepower limit and not the intake manifolds.
Same thing is happening with Tom's tests.
The stock L98 head flows about 184 cfm @ 0.431 lift (depending on the flow test you reference).
Looking back at the chart above, all these manifolds flow more than that, so the head is limiting the peak power in these tests.
Then why are they different at all?
Even though the intakes all flow more than the head, they still create a loss when put in series with the head, better flowing intake equals less resistance less loss.
The intake manifold's inertia ramming and wave tuning create 2 to 6 psi at their peak tuning rpm.
Like a narrow band supercharger that pushes air past the head restriction.
This^ whole "chunk" is wonderfully explained. I've been thinking about it for days, since you wrote it, and I love the way that you presented it. I do have a question though; why do you suppose the T-Ram is so far off the SR? I believe the SR runner length is ~10-11" from head flange to plenum, when I had my T-Ram, I measured ~11" for that same dimension. There may be a cross sectional diff, but as you pointed out, they're all flowing well above what the head flows, with the stock cam. So, it makes sense to me that the SR and AS&M runners were close (9 hp), and it makes sense to me that the MR was so far off the rest (no tuned ramming at all, and probably pretty low velocity), but I'd think that the T-Ram ought to be right in the mix, with the SR and the AS&M. Thoughts on this?
Originally Posted by greggpenn
Adjusting the base? You talking about timing via dizzy position or something else?
I have to wonder what the comparison would be -- if complete tuning via chip alteration as I've done with my 383?
Everything has it's pluses and minuses. You are doing an absolute GREAT job letting us see where they are. My only regret is we all can't take turns FEELING them in a 2k# frame! DAMN! That has to be fun!!!
Greg, thanks for your enthusiasm about this whole process. It's been really interesting and fun. I've held off doing other things to the Kart (a 400, and porting the 113's, some more cam and LT headers) because of this test, and especially BHR sending some intakes....that was a game changer for the testing and definitely made it worth while to hold off on the 400, for doing this.
WRT to the timing (and fuel), yes, "turning the distributor" is what I did for each intake and especially so for the MR while on the dyno. Since the MR makes such a different shaped tq curve, the spark curve in the stock tune is not good for the MR, as you rightfully pointed out. Same w/the fuel curve, in the stock tune. For that reason, we did more pulls w/the MR and played w/global timing (and global fueling via fuel pressure)...only focusing on optimizing the total timing at WOT, at the hp peak...to get the highest peak that the intake could make on that engine. Of course that "setting", wouldn't likely be ideal for the rest of the RPM (or throttle positions), due to the TPI spark tune (and again, fuel too)....but total timing at WOT is a fixed value, and by playing w/the dist, and not worrying about timing for any other operating condition, we were able to optimize the timing for peak hp. Therefore, I don't think a tune/chip would provide a much better result that what we saw on the dyno. Possibly a little more peak tq and maybe a little more hp with more fuel (FPR was maxed out), but not a lot. Based on what we did and saw, I don't believe that any amount of tuning would get the MR anywhere near the others.
As for feeling it in the Kart....it's pretty good. The Kart was an '89 Z51, so it has a 3.31 gear, 6 speed, quick steering etc. Full throttle is useless in first and second gear. FUN....but not fastest. It won't hold traction until 3rd gear and that is when you can really "feel" the pull/pwr/tq, and it feels pretty wicked. 4th gear feels great too, but by then, you're already being irresponsible on a public road. I think more gear would make it more fun on the street and increase the "pull" in 3rd (w/o being too much for the tires), and 4th, while lowering the speeds in those gears. As for the rest of the car's driving characteristics, it's surprisingly benign. The cage radically stiffened up the C4 frame, so it doesn't shudder, flex, crash over bumps, none of that. Taking 1000 lbs off the car made the rest of the dynamics feel "effortless"; cornering, braking (even w/the stock 12" rotors and plain-Jane pads), it does astounding things, very easily and w/no drama. All the drama comes from the gas pedal and the side pipes. Between the sound, and the hit of thrust and wheel spin, when you hit the gas, it's like a bomb went off. I love it.
Build one! Beater C4's are still really, really cheap. You can pay for the car purchase w/all of the parts that you can sell off of the car.
This^ whole "chunk" is wonderfully explained. I've been thinking about it for days, since you wrote it, and I love the way that you presented it. I do have a question though; why do you suppose the T-Ram is so far off the SR? I believe the SR runner length is ~10-11" from head flange to plenum, when I had my T-Ram, I measured ~11" for that same dimension. There may be a cross sectional diff, but as you pointed out, they're all flowing well above what the head flows, with the stock cam. So, it makes sense to me that the SR and AS&M runners were close (9 hp), and it makes sense to me that the MR was so far off the rest (no tuned ramming at all, and probably pretty low velocity), but I'd think that the T-Ram ought to be right in the mix, with the SR and the AS&M. Thoughts on this?
I've been real busy ... but been thinking about what your asking.
Need some time to write my thoughts in a way that makes sense
In the mean time, none of these three intakes (TRam, SuperRam, Siamese) are running away from the others.
Even in the TTT article, the results somewhat mimic yours.
The higher flowing SuperRam pulls away from the others more.
The Tram does breath better than the Siamese above 5000rpm, but the Siamese has a slight edge down low.
I tossed in the AS&M Long Tubes vs. the Siamese.
Still think on a STOCK L98, below 5000 rpm, these might outperform all the others.
Certainly going to feel that torque difference.
But these STOCK tests are interesting on many levels.
Sorry ... ahead of time, if I'm going to many stops on the "Theory Train"
The Mini Ram (300+cfm) flows so much more than the L98 head (184cfm) that it really doesn't hurt the L98 head flow numbers.
The wave and ram tuning "Boost" at 5000 rpm is so low that it isn't contributing much either, the majority of that 2 psi is coming from the 5-1/2 inch runner in the cylinder head and not from the 3-1/2 intake runner anyway.
The Mini Ram, not hurting or helping, we could argue that it's like having no intake manifold at all, and the Mini Ram dyno curve is actually the L98 Long Blocks dyno curve just from straight up mechanical air pumping, with no contribution from wave or ram tuning.
If that's true, the difference between the Mini Ram curve and any of the others, would be the additional power (or loss) from the harmonic and ram tuning for that intake.
In one of his airflow books, John Baechtel says that harmonic or wave tuning adds about 2% more filling capacity (horsepower) and intake runner ramming another 18%.
Just comparing the area gain of the Super Ram to the Mini Ram (L98 Long Block) curves, at 4300 rpm the Super Ram's 287 HP is 14.8% more than the Mini's 250 HP.
Baechtel is talking about race engines, so 14.5% for a street engine sounds about right to me.
Damn....I thought the harmonic tuning parts would be more significant than up to 2%. That is a very small contribution....and would also mean, I would think, that the off-phase penalty would also be a similarly tiny percentage.
Last edited by Tom 400 CFI; 10-30-2023 at 10:57 AM.
But these STOCK tests are interesting on many levels.
I agree. I was looking around the 'net a couple nights ago and found THIS article from David Freiburger, 1992.
"All tests were completed on a Cottrell Racing Engines 383 small-block with Crower 6-inch rods, a Callies crank, and Ross pistons that squeezed 10.61:1 compression into the 74cc Cottrell-modified Air Flow Research aluminum heads. The cam was a tight-lash, single-pattern roller with 240 degrees of duration at .050-inch tappet lift, 112-degree lobe-separation angle, and .570-inch lift. A Jesel belt drive .....
To be fair, we must point out that this high-rpm engine with its long-duration cam and big cylinder heads is predisposed to work best with a short-runner manifold."
Very similar to the TTTT tests. I knew very few people who had an engine like ^that^ in their 'Vette, F-Bod, G-bod....back in 1992. Very few, and the few I did see (at the drag track) at that time, were not what I'd have considered to be "street cars". They'd come to the track in a trailer.
Update: Finally pulled BHR's AS&M runners, ported plenum and the base last night, and packed 'em up to ship them back. Prototype TPI up next, if it's bad weather next weekend (meaning, I won't be painting the house! ), I can put that one on, then wait to see if we have any more nice weather for a trip down the hill, to the dyno, again. Took this "photo op" last night....I wish I'd thought to un-box TTop350's and include it in the pic, but I missed that opportunity.
Last edited by Tom 400 CFI; 10-30-2023 at 11:00 AM.
Thanks, I'd LOVE to test one, too. I have ideas about how it'd do, but as you already know, I've been skooled a few times in this whole process, already.
Originally Posted by SuperZZ4
They where testing the heads, not the intakes ....
I thought they where suppose to be teaching us?
Designing, picking heads, intakes, carburetors, dyno testing, you have to know where your engines flow restriction is or your in for frustration ...
That's pretty funny, I saw that episode in the season 7 list, but skipped it, b/c....."what's carb'ed LS's got to do with ME!?"
Turns out that it's pretty relevant, when looked at the way that you're seeing it. Freiburger should know that stuff, but it's easy to get lost in the moment....I suspect he went into it w/a preconceived notion of what intake would do the best, then got mentally "stuck" on the rather flat results? IDK...just a guess.
It's funny, 245 seemed huge when those heads came out in, what...'02? In now days world, that seems like a pretty marginal flow number...even for OEM stuff. MOAR!!
At the AS&M dyno session, my son got a vid of one of the pulls, and he finally shared it with me, so I thought I'd throw it up here b/c there are a couple interesting things in it, IMO.
First, the dyno op using the dyno brake to drag the thing down to "500 RPM" starting point. IDK why he doesn't just get it rolling in 1st, shift to 4th and then coast or throttle it to 500 RPM...then go for it but he did it this way every time. NBD...just interesting way of doing it I guess.
Second...my god, listed to that poor turd scream in agony, trying to get from 5k up to 6k!! LOL!
Third, if you listen closely, you can hear valve float right before he chops the throttle. Lol, 2.
Thanks for the props, Tom3!
I have been very surprised by every test since the beginning, except for the MR. The very first test, box stock engine w/no air filter, and home made dual exhaust/no cats, optimized base timing and a 160 stat, it did 241 at the wheel! And this engine was no fine example of care and maintenance! Anyway, the rest of the intakes have really impressed me for the pretty massive gains, as a single bolt-on part. With the SR, 289 RWHP, that's got to be some where around 320 crank? (~10% drivetrain loss?). It's definitely surprising to me that a ratty old, uncared for TPI motor is easily doing over 300 (crank) with no tune, no valve covers off.....I certainly wasn't expecting that, when I started into this whole adventure.
This^ whole "chunk" is wonderfully explained. I've been thinking about it for days, since you wrote it, and I love the way that you presented it. I do have a question though; why do you suppose the T-Ram is so far off the SR? I believe the SR runner length is ~10-11" from head flange to plenum, when I had my T-Ram, I measured ~11" for that same dimension. There may be a cross sectional diff, but as you pointed out, they're all flowing well above what the head flows, with the stock cam. So, it makes sense to me that the SR and AS&M runners were close (9 hp), and it makes sense to me that the MR was so far off the rest (no tuned ramming at all, and probably pretty low velocity), but I'd think that the T-Ram ought to be right in the mix, with the SR and the AS&M. Thoughts on this?
Greg, thanks for your enthusiasm about this whole process. It's been really interesting and fun. I've held off doing other things to the Kart (a 400, and porting the 113's, some more cam and LT headers) because of this test, and especially BHR sending some intakes....that was a game changer for the testing and definitely made it worth while to hold off on the 400, for doing this.
My take is bc on the SR the runner ends in a big open plenum where as the T ram it ends with a tank covering the entry of it then the air also has to travel and make hard turns the TB entry is also blocked by the runners
Could be. IDK. I guess you'd have to flow one runner of each intake and see...then pull the tank off that runner's side on the T-Ram and flow test again.
I wonder what the distance is between the mouth of the T-Ram runner and the "roof" of the side tank, vs. the floor of the SR plenum and the underside of the lid of the SR? I think it's a greater distance on the SR...but not a lot I don't think.
The next question (in my mind), then, is: Why didn't Ed Hamburger simply use the Super Ram on the Firehawk?
Great test results and thanks for all the hard work. I enjoyed looking at all your testing.
I've done a much smaller test in comparing the SuperRam to the MiniRam. My setup is far from stock.
383, AFR 195 Comp heads, XFI 280, 36 lbs injectors, long tube headers custom 3" y-pipe into a Flow master merge pipe into 4" single exhaust running through a Hooker muffler. I tune it with Dynamic FI ECM I also have a 4" CAI to make sure it's getting enough air.
I've modified my SR by cutting the runners along with enlarging them then working on the base also by opening up the runners and matching the runner openings and the exit ports to match the felpro 1205 gasket. The interesting part is with all the porting and effectively shortening the runners by 2" the power curve is basically the same as a stock SR intake. The SR on my Firebird with a 6spd and 3.92 gear made RWHP 442HP@5,700 and 465TQ@4,150. The car has tons of mid-range power and is a blast to drive. My best E.T with the SR is 11.68 and highest MPH is 118.5 in the 1/4 mile.
The MR intake I just ported a little bit, it produced 465HP@6,200 and 432TQ@4,900. The fasted 1/4 mile with the MR is 11.65@121.7. The MR with my set-up works the best. Even though it gives up a ton of power below 4,500 rpm it's not even noticable when driving and pulls like a freight train 5,000 rpm and up.
I would love to test the HSR but I don't think it'll fit under my hood. Dyno Results SR base SR runner
Again great work and thx for sharing.
Tom
EDIT: Re to, @SuperRamFormula
Thanks for posting, Tom, is it? That was some fantastic data! Your engine is much more like the engine in TTTT, and also Freiburger's 1992 TPI intakes comparo, engine. Your results are like SO many, I've read about, where the MR gives up down low, but is faster and quicker at the track. 383Vette on the 'Vette forums went through an almost identical process as you; he had/has an '84 'Vette and was running a 383 w/heads/cam/exhaust and an SR and I believe he had it in the 10's....then switched to a MR, made almost the same observations as you have, and went faster and quicker.
On this stock engine, though, it's a different story as there is "nothing there" from the engine part of the equation, to exploit the MR's potential; it lost from idle to hp peak, and by the time it gets to the hp peak...the heads, cam and exhaust have checked out already.
You might talk to "SuperZZ4", on here....specifically about the siamese'ing of your runners. He's run a BUNCH of flow bench tests and used smoke machine, to boot, so he could see how the air is flowing. His work has been incredibly interesting, revealing and educational. He may correct me here, but I THINK he found that knife edging the divider between two runners that do not pull air at the same time, causes more turbulence and reduces flow, as compared to a blunt divider in the same circumstance. IOW, a knife edge between the two throttle plates of a TPI/LT1 intake is OK, but paired runners that pull air at different times creates turbulence, IIRC. I wonder if that is why the work you did, didn't result in a higher power curve? Or it could be, as mentioned earlier in the thread, that your heads+valve lift may be setting the flow limit? IDK, but either way, you've got a strong running car that sounds like a blast to rip on the street!
Last edited by Tom 400 CFI; 11-05-2023 at 08:12 PM.
I will say the car runs much smoother with the SR installed and has almost to much torq, I've had cluch slippage issues with it installed and a larger M/T drag radial.
The MR has low speed air distribution issues which cause the front cylinder to run lean and the rears to run rich. I made a remote air bypass valve and added a port in the rear of the intake so its adding air to the rear and it seems to help. I'm considering trying a larger injector in the front 4 and changing the base setup in the tuning program to see if I can even it out a little more.
I think you're correct on the knife edging on the runners as I was told that by another guy. I think while they're off I'll fix that and maybe see what happens. I will say that even with the big cam, larger and shorter intake ports I was a bit disappointed that I couldn't flatten and extend the power range. John Lignefelter himself even said when he was comparing the SR to the LT1 intake that if the car was a manual trans the short runner intake was the one to use.
As far as 1/4 mile times I think if I had a 3.73 or 3.54 with a wide ratio trans instead of the 3.92 with the close ratio trans the SR might perform better. The MR just loves to run, I shift at 6,200-6,500 and it drops right back to around 5,000 and it's all GO.
I was kind of shocked on how much bigger the runners were than the stock tpi.
I'm guessing about the same rpm range, but power may increase a bit until we reach the stock cam/ cyl head flow limits.
10-21-2023, 11:56 PM
Shows what CAN be done, which I think is important for those who can't/don't want to tune, then get "stuck" not doing mods b/c they've been led to believe that you need a tune. Some mods you may, but many can be worked around and it can be good enough. 
