3rd Gen / L98 Engine Tech 1982 - 1992 Engine Related

Want more power out of 350 tpi?

Old 05-17-2010, 07:27 AM
  #31  
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You guys are approaching this the wrong way. This isn't an intake designed to make HP...it's designed to make torque. Torque cannot exist without HP, since HP is a calculation of how well an engine can work and is based off torque and RPM, while torque is an actual measurement. It's a torque intake, so work on improving TORQUE.

Since it takes RPM to make HP the higher your torque peak, the higher your HP peak as well. A well running engine will peak 1200-1500 RPM for HP above peak torque. If you were to port the intake properly to raise the torque RPM, then the HP will also increase accordingly.

BTW, the 383+ TPI is not a 'waste of potential'. If you feel the way, then you obviously are biased to HP. This intake is for torque. What I feel is a waste of potential is a TPI engine with a larger bore than necessary (434 @ 4.155") when the major contributor is the stroke, not the bore. The extra bore size just makes it harder to size the intake accordingly especially when you approach 400 cubes. a 408 would be a better choice, for example. As long as you aren't shrouding the valves, going up on stroke and not going too big on the bore is the way to go. The TPI relies on somewhat of a flow restriction in order to be tuned, as well as intake runner length and size matched to the cubic inches of the engine at your target peak torque RPM (someone else's ported 350 TPI intake might not work well on your 383, for example) so don't get all twisted up on CFM and flow numbers. Efficiency is the key. That's why those extrude honed intakes work so well.

Different type of engine. Different rules apply to retain it's tuning effect.

The biggest problem with the base is it's angularity problem into the cylinder head. The runner lies awfully flat entering the head, then slams into the port roof and has to change direction. The head side of the intake is actually larger than it needs to be compared to the runners and the first half of the base so the pulse strength weakens already somewhat before even reaching the head. The only fix is alot of welding and porting/sizing, or the FIRST TPI intake.

I think TPI engines make great street motors. I've built a ton of them. Problem is alot of people expect them to deliver things they were never designed for.
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Old 05-17-2010, 12:00 PM
  #32  
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Originally Posted by gtadude View Post
this show me your inexpirence in engine building and cars PERIOD... i dont race dynos or flow benches, the only numbers that matter are on the track. i be willing to bet you never even built a tpi engine or one that was worth a dam. i dont see any engine specs posted by you or any help....so please me a river
Join date: Apr 2010

I've been here 10 years longer than you, and on TGO as well. I know my way around these cars pretty well. My specs for my old 91 L98, my 85 Z28, and my 00 TA aren't hard to find. Both cars listed in the sig were built by me, and would embarass your "400HP" TPI car. And if track numbers matter so much, be sure to post up your 102-105trap speeds if you ever run that thing. Then tell me it's making 400HP.

And you're not helping too much either, posting misinformation. With a response like that, you obviously DON'T have any proof of your claims.

Last edited by Marc 85Z28; 05-17-2010 at 12:04 PM.
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Old 05-24-2010, 09:43 AM
  #33  
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irrelevent

I've been here 10 years longer than you, and on TGO as well
irrelevent

My specs for my old 91 L98, my 85 Z28, and my 00 TA aren't hard to find. Both cars listed in the sig were built by me, and would embarass your "400HP" TPI car.
irrelevent

And you're not helping too much either, posting misinformation. With a response like that, you obviously DON'T have any proof of your claims.
wow you act like its hard or some secrect to make 350-400hp with a tpi engine!!! i did not post any missinfo, you have not posted any info. you know so much post up YOUR combo then???
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Old 05-24-2010, 05:09 PM
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So I take it by the above post, that you have absolutely no evidence that you own a 400 hp engine.
You made the claim. It's not up to US to prove you wrong.
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Old 06-09-2010, 09:24 AM
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Oh geez, not another enthusiast website gone TGO. Gentlemen, please leave the drama to them! That's why I left, I was tired of rednecks bickering about meaningless stuff.

These silly wars on numbers can be settled easily. Post your numbers (a link to a dyno sheet or 1/4-mile run slip is perfect) and let the others see. Let's not be like the dumbass ricers arguing "I have 2,000hp ... but I have 5,000hp".

And let's not forget, this thread was started for advice on getting more power out of a TPI engine. If you have good advice, please post up. If not, please don't.
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Old 07-05-2010, 11:14 AM
  #36  
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There are so many aftermarket players that it should be no problem making your TPI system run at higher rpm's.without running out of breath. As many cars are daily drivers (DD)they would rarely be run over 5000 rpm, most if not all street drivers will spend most of there life at or around 3500. I myself would and do focus everything in that area, with a top rpm of 5500 max. And all I have is a carbed engine. Do I want to go to TPI, hell yes I do, I want all the low end I can get, but then again I am not going to run the car a strip. I want good low end with some top end, but to me MPG (miles per gallon) is something you should not to overlook. That is if you are going to use it as a DD.
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Old 07-05-2010, 12:10 PM
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Just get a crate engine and be done with it. 350HP @ flywheel should get you close to the 300HP at the wheels.

http://www.summitracing.com/parts/NAL-19201330/
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Old 08-03-2010, 10:26 AM
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My favorite combo which should put you in the 12s and be right around your RWP goals in a cloth hardtop car and pass the sniffer if you have to

Ported plenum
TPIS base
ASM runners
Long tube Headers(love the TPIS ones if its a Vette)
Vette heads with a valve job and pocket porting(like the 89-91s best)
Descreened MAF if you are a pre 90
AFPR-try 5 pounds more than stock to start
MSD ignition
Plugs gapped .05 wider
SLP cold air if its a Firebird
TPIS Superprofile cam with 1.6 stud mounted rockers or ZZ9 with 1.5 if you want more lope
ASP pulley set
Driveshaft from an LS1
10 bolt rear with girdle,Yukon axles,373s,welded axle tubes and new bearings
2200-2400 stall
Mickey Thompson DRs
Boxed LCAs
Subframe connectors
Catback of your choice.

Want more oomp at upper rpms get a Superram manifold and a ZZ409/Accel cam. If you are running a 90-92 car you will need to burn a prom if you are running a ZZ9 or bigger cam. If you are using the stock prom set your timing to 13 degrees on a MAF car(87-89). If you have a Vette you must get rid of the stock cat.

This combo works great and can be driven anywhere. It will smack up a bolt Lt1 easy and give fits to mild LS1s as well especially from a dig. Good mileage too!!
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Old 08-03-2010, 10:46 AM
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Originally Posted by Mike 92LX View Post
My favorite combo which should put you in the 12s and be right around your RWP goals in a cloth hardtop car and pass the sniffer if you have to

Ported plenum
TPIS base
ASM runners
Long tube Headers(love the TPIS ones if its a Vette)
Vette heads with a valve job and pocket porting(like the 89-91s best)
Descreened MAF if you are a pre 90
AFPR-try 5 pounds more than stock to start
MSD ignition
Plugs gapped .05 wider
SLP cold air if its a Firebird
TPIS Superprofile cam with 1.6 stud mounted rockers or ZZ9 with 1.5 if you want more lope
ASP pulley set
Driveshaft from an LS1
10 bolt rear with girdle,Yukon axles,373s,welded axle tubes and new bearings
2200-2400 stall
Mickey Thompson DRs
Boxed LCAs
Subframe connectors
Catback of your choice.

Want more oomp at upper rpms get a Superram manifold and a ZZ409/Accel cam. If you are running a 90-92 car you will need to burn a prom if you are running a ZZ9 or bigger cam. If you are using the stock prom set your timing to 13 degrees on a MAF car(87-89). If you have a Vette you must get rid of the stock cat.

This combo works great and can be driven anywhere. It will smack up a bolt Lt1 easy and give fits to mild LS1s as well especially from a dig. Good mileage too!!
That sounds like a nice combo........ for 1998. Things have come a long way since you had your car.
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Old 10-29-2018, 10:41 PM
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Re: Want more power out of 350 tpi?

I have a '91 5.7L and I want to do some slight modifications, nothing too big. Some friends were telling me to put in the new LS intake and cam, would that make any noticeable difference?
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Old 10-30-2018, 08:06 AM
  #41  
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Re: Want more power out of 350 tpi?

You can't put LSx parts (in general) on a Gen 1 SBC (small block Chevy) engine. They are totally different engines.

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