i know that in a na setup the stock tpi intake is very restrictive but under boost is it just as bad. i plan on running a set of afr 190's and a set of headers. would the stock l98 cam work i know that some times smog cams work better than a hotter cam under boost do to the fact it dose not get blown out the exhaust. so in all i would like to do heads, headers and push about 8-10 psi of cool boost into it. would this work out what type of power.

 

Intake plays less of a part in a boosted application. You will see a tremendous amount of tourqe from a blown tpi intake and yes it still will be limited in it's powerband. I would move to a specific blower cam. Som e of the cams in the L98's have tight LSA's and you will benefit from a blower cam (usually 114 lsa or higher)

 

The TPI intake works great on boosted applications!
I was running 11.0's - 10.90's whith 15lbs of non-intercooled boost. I was also pushing it to 7100rpm, don't believe everything you read about the low rpm limitations of the TPI.

 

so the stock tpi is good but the cam is not and i should get a set of headers and heads. right

 

you will definately need to pen that exhaust up. Although the tpi intake does quite well under boost the exhaust stroke will be a different story. It is a big bottleneck in the power making equation. If you would give some more specifics about your planthe guys here can give you a good list of choices from experiences.

Generally a 114 cam with decent sized runners(ported 195's) and a cleaned up intake will produce a lot of power for the street.

 

i was thinking of a set of afr 210's and a set of headers with a blower cam on about 8-10 psi

 

there may be some on this board who will disagree and to some extent my self I do too, especially for the average power adder street car. but, the performance eseminar I went to a coupla years ago in denver, I think dutweiler and a few others were there they said on a blowthrough boosted application the best flowing heads , intake, TB are as critical here as they are on a normally asperated max effort engine.

 

i would just like to be able to stomp the snot out of the stock ls1 4th gens out there

 

Build a good 350 and put an F1 on it and then put your money where you're gonna need it(traction anf fuel).


Pete

 

sure it is...because you'll make more power on less boost and your motor will be more efficient

what would you rather have?

20psi and 800hp

or

8psi and 800hp

???

 

Pete, please stop attaching photos that do not have any relavence to the subject. It takes up space on the site.

Thanks.

 

I agree with you 100%. I managed to pick up almost 4 tenths by porting my upper plenum, and going to a 58mm throttle body (over stock plenum/throttle body).
I do believe the TPI intake can work very well on a forced induction application, and that other more critical components should be changed before you will have to switch intakes. A good set of heads, a decent hyd. roller cam, and a set of 1 3/4" Hooker long tubes. This combination with a good supercharger (t-trim, y/s-trim, d-1sc, f1, f1-r) should give you more than enough power to beat up on most street cars out there!
just my .02

 

If that’s all you want just learn to drive and tune what you have. The last time I was at he track with my L98 ’87 Formula was in august, on a hot, 90some degree night. Most of the LS1’s were running high 13’s and low 14’s… I was in the mid 13’s. That was on stock radials, with a stock engine, tranny, rear… just a cold air intake and cat back. These things have much more potential then people give them credit for

 

Well, if you gave me the 8psi combo I’d turn it up to 20 and shoot for 1100hp

Being realistic, to get 800hp out of a 350 at 8psi you’d have to be turning some SERIOUS rpm’s, at that point the 20psi version would be more dependable assuming that you’ve got low enough compression or high enough octane that you can tune it right.

To answer a few other things that have been mentioned… the big restriction on the stock setup is the crappy heads, almost anything is an improvement, even a set of LG4 heads, but if you go with something that flows over 200cfm on the intake you’ll need to start modifying the TPI setup to take advantage of that additional flow. I’m not really sure what the point is with going with AFR 210’s or 220’s if you will never get a TPI to flow more then a set of 190’s will flow…

 

i would like to go with the 210's due to the fact that later i would like to upgrade to a HSR

 

LOL...i was just giving an example. And actually you can get 800hp out of 8psi on a 350 without turning serious RPMs. I bet with a set of GREAT heads, decent headers, and either twin 60s or twin 62s it'd be possilbe. Or for a single setup a T-80 could do it. You just need some great heads

 

then you are going to be doing some major work to those intake ports on the HSR because 210s require a 1206 gasket and it's gonna take some machinig and welding to get it to fit correctly

 

yes that is true but from what i see there is tones of meat there that can be cut on

 

no, you are wrong. I had it. I didn't want to spend the money to have it fit my track 1 heads

another person and this board had to do a lot of work to get his to fit CORRECTLY. I'm sure you could port the crap out it and get it really thin and eventually watch it crack but then you are into more problems

do a search for him bbhunting he explained how much work he had to do in this forum i believe

 

wow its that off hu never did a direct compair. then what should be used with a head that big if the HSR dose not fit a big mouth wont eather right

 

Even a great set of heads will not allow you to breath more air then the engine can ingest. Let me throw some real #’s at you so you can see what I’m talking about.

VE and torque curves have exactly the same shape. Even the best breathing engine will have it’s VE drop off by the hp peak, on purpose built engines often to the 80-90% range (traditional OHV engines drop off to around 65%, so I’m giving a lot of leeway for someone that knows way more then any of us about ram tuning/scavenging under boost if it’s possible at all). So lets say 85% and put the HP peak at 6000rpm (so we’re already building an engine that would probably need to be built rev to 7000-7500 to be able to use the HP it’s making). At 6000rpm, 85% VE a 350 will be pumping 516cfm. No matter what heads you put on it, it will not flow more then that, that is what the engine is capable of moving based on the displacement of the pistons moving up and down (BTW, that could be fed by a port that flows around 200cfm at a lift somewhat short of whatever the lift is on the cam, this is in the range of cleaned up stock heads, and less then a set of vortec heads will flow).

Now lets give it 14.7psig boost with a next to perfect, ice cooled intercooler with an outlet temp of 85* (I use this in most of my examples since it is something that is just about impossible to achieve but makes the math easy (pressure ratio = density ratio) and gives the most optimistic answer). That will double the mass of the air that’s forced into the engine to 1032cfm (I know, I’m giving a volume flow for a mass flow, but you can calculate the mass knowing the density (air temp and pressure) of the air, which is actually 71Lb/min and I’m just converting using the # that we have), which if mixed with just the right amount of fuel and if the ignition is perfect is just about right for 775hp. BTW, doing the same math with 8psi with the next to perfect, no loss intercooler amounts to just under 600hp. And to get 800 HP from that combination you have to move your HP peak to 7700rpm, so you'd probably have to build the engine to spin to at least 1000rpm over that, which is what I call serious rpm where you'd need high $$$ parts to keep the thing from flying apart.

 

Isnt it true if you run more that 9psi of boost in your engine it can mess up the crankshaft or blow it apart.

 

no offense here, but calculations are all good and nice but what thing you are missing is real world results. You have anything to prove what you just said? Are you forgetting that FI motors usually typically put it over the 100%VE mark. I've been around quite a few turbo motors and blower motors. It can be done. its all about AIRFLOW. If you have the heads that flow the numbers and efficiently use the cfm that the turbo/blower are putting out you will not see a large backup in the intake which in turns leads to boost/psi. If the turbo/blower is big enough you will hit the number you want at a relatively low boost number. Now it may not be a practial application.....maybe have to use a very large unstreetable blower/turbo but my point is you can do it

 

Depends. If you're running 9psi and only making 300hp, probably not. If you're running 9psi and making 500+hp then its more likely. It just depends on the power level of the engine and if the crank is in good shape. Detonate the engine however, and all bets are off.

 

I have close to 300 hp now if i were to put a procgarger system on with 9lb of boost how much hp would i get. I have a jasper 305 with only 10k miles on it you think it would be ok?

 

You’re missing the point procharged. Yea, engines often go over 100%VE, I never said that they didn’t. But they do it at their torque peak and they do it through ram tuning and scavenging effects. A lot of which will not work on a turbocharged engine (you will not get scavenging on a turbocharged engine no matter how hard you try, and even a 4% or 7% harmonic tuning increase will not overcome VE loses at the HP peak, it won’t even overcome the pressure losses due to the restriction of the turbine in the exhaust stream.

I agree with you that there is a difference between theoretical and empirical #’s, but the theoretical #’s can usually predict the empirical #’s if you examine the system closely enough. What it comes down to is show me a boosted 350 making 800 hp on 8psi at under 6000rpm. You won’t since no matter which way you look at it you will not have enough air flow to do it. At 100%VE (lets assume that the torque peak is at 6000rpm), you still only have enough air flow for 680hp.

 

Sounds like a challenge!
I bet one of those ChiTown boys can make it happen, or even one of those guys from Delaware!

 

You give me a big enough blower/turbo combined with 18* heads and i'll make it happen

i just dont have the funds

 

you have to use a TPIS miniram made for a 1206/1207 or setup like this if you wanna go with a bigger head, er...atleast i think thats what your asking?