Ok whats the max HP I am going to see from a TPI set up? I seen a post that said TPI isnt good after about 350HP. I want to crank out about 450HP and 450lbs with a 383. If the TPI doesnt get me there what should I use? I want to stay with fuel injection if at all possible but I know radical changes will give me a headache when trying to program the prom. Any info will help me out.

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88 Firebird Formula
350 T.P.I. (Stock unfortunately)

 

I would say that about 350-375hp mark would be about right for a long tube setup (not the stock tpi, but fully optimized- base, runners, ported plenum, etc). But the torque would be absolutely brutal.
The SuperRam(maybe ported) will make the hp you want at a higher rpm, and still provide great low end, but not as much or as low rpm as a long tube setup.
A Miniram setup has the potential to make some serious high end hp, but suffers in the low end department (compared to the others).
Keep in mind any engine built with care to match components with each-other will perform best. So you may be able to get the same numbers from different intake designs, but on different cam/head pakages. And the power will be made at different rpms.
I think a good system is to decide on the intake and work down, because the intake very much dictates the cam and head choice. I wish i had.
Just my opinion on choice, I think the SuperRam is a better street setup, making power at a lower rpm and good low end torque so that too steep gears are not needed. I own one and really like the drivability.
If you're hell-bent on power the Miniram seems to be the choice for that.
This is all just what i think so take it for what its worth.
good luck.

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'88 RS (originally 2.8)
-350, .040 over, vette alum. L98s, stock tpi.
-305 injectors & chip
-TES headers & edelbrock cat back
-3.73 gears, 700r4.
Best with 2.8-17.4@77mph
Best with 305-15.0@93mph
Best with 356-13.7@101mph
on a 2.050 60 ft.
(Damn the 2.8!)

 

Good post Fakeiroc87, I agree on all points... except the point about the long runnered set-up making more torque than a Superram set-up. The Superram will actually not only make a broader torque curve than a long runnered set-up, but also more torque. The best comparison I can give is to look at a couple of advertised LPE 383's.... the first one is a 383 with ported D-port heads the LPE 74211 cam and Accel large tube runners with the Accel base manifold. This motor is advertised at 395 HP and 450 ftlbs of torque, wherease they then take the exact same motor, but insert the 74219 cam in place of the 211 and insert the SR in place of the ported plenum and Accel runners and this motor makes: 440 HP and 480 ftlbs of torque... a 45 HP increase and 30 ftlb increase over the long runnered set-up.


IH8Ford,

I would guess a stock TPI set-up even on top of a 383 with great flowing heads would bottleneck that motor down to 340-360 HP, simply because it is impossible for the stock TPI set-up to flow enough air above 4500 rpm to make any power. Aftermarket large tube runners with an Accel manifold help quite a bit with jumps in HP of 15-25 HP on a stock motor, and 30-40 HP gains with a modified motor are not out of the question. A further jump up over that to the Superram would probably allow you to reach your intended goal of 450 HP/ 450 tq, simply make sure you have a quality set of heads on top of 383 or more cubic inches.

good luck
Todd


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85 Vette
383 SR Motor
11.55 @ 117
1.552 60 foot
http://corvetteforum.net/c4/beach_bum/

 

how about using a ported base with siameesed runners would that be in the middle of the long tube and super ram?

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91 Z28 slp headers adj reg accell cap rotor coil comp cam roller
random tech cats flowmaster catback
new motor in

 

Hmmm, What if I ported the base intake, upgraded to a 1000CFM carb, and ran a procharger/Paxton/vortech? Would that give me the numbers I am looking for?

 

I have 375hp a 500ft lbs of torque! you have to love these 406's! Oh yeah all TPI through the stock manifold.

 

Todd85- I agree, the SuperRam would make more torque than the long tube setup simply because it won't be a restriction at at the point that the long tube becomes one, and at that point and thereafter it will make more torque and essentially, more power.
What I meant to get across was that the long tube setup would start making the torque lower in the rpm compared to the SuperRam. I know they advertise no loss in low end but there is and you can deffinately feel that it is not as strong down low.
But say he builds a smaller engine that is designed to make power power below say 5400 rpm, then I think the long tube setup would be better because you have the power sooner and at 5400 rpm that setup is not a bottleneck. I'd say making power beyond that would be better left to the SuperRam. This logic is better for smaller engines like a 350.
On his 383, I agree with you totally, the long tube setup probobly just wont feed it well enough, and the SuperRam would dominate that comparison. This is why all those tests are done on 383 engines and such. The SuperRam just has a higher capacity to feed them. I do still believe that even on a 383 a long tube will outperform the SuperRam for the first 1000 rpm or so.
But then who drives thier engines in the first 1000 rpms only.

[This message has been edited by '87FAKE-IROC-Z (edited August 14, 2001).]

 

Hey Todd,
I just checked out your website, very, very informative- looks like you've got alot of experience with long tube and SuperRam comparisons, so I'll take your word for it,
I personally have never run a modified long tube setup. Great site man.
Oh ya, I especially like the gear selector chart, I think it is right on- too many people are going for more gear when they don't need it. I'm switching my 3.73s out for 3.27 now, I got those gears when i was stupid and had no idea how to match parts.

[This message has been edited by '87FAKE-IROC-Z (edited August 14, 2001).]

 

well my 406 is almost complete. the guy who is building it has a 406 just like mine in his vette. the only difference is i went with AFR 195's and a bit more wilder cam them he did. his #'s are 450hp and and almost 580 TQ. so im hopeing its 475hp 600 tq *again hopeing* best thing is, its all emission legal.. haha.. take that tree hugers!!

 

opps i forgot to add all the intake stuff.. it is a BBK 58MM T.B., TPIS long tube runners, TPIS big mouth intake and everything is ported.

 

Yeah Long tubes will always make power sooner than a SR or MR, but when ever you have a small loss of torque at 2500 rpm... it usually means there's a big payback up above 5000 rpm. To me, thats why god created Torque Converters

Thanks on the webpage !!
I have experience with the Accel large runners, but I do not have any experience with the ASM runners which seem to give a bit more than the other long runners.... I have no clue why.

talk to you later
Todd

 

Just thought I'd be the instigator and say there is no limit... no realistic one anyway.
With boost or nitrous the hp you are looking for would be easily obtainable, if you want a good example ask Willie. Its more a matter of how you want to get there, and what you want to spend.

 

There was a good post on about if the TPI has a HP limit. U should do a search for it, it has alot of information.

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89 RS

STILL Looking For:
An 87 IROC-Z28 350 TPI