I was looking at a 1991 camaro rs for $1700, it has a new paint job its all mint...but i asked what is in it he said 305 tpi, i know it has 170hp stock not much, what can you do to get a few extra horses that doesnt cut into the bank to much
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thirdgen-fan

 

305 TBI you mean. I shouldnt be the first to tell ya what to do with it, but your never gonna be too high on the food chain. If its in good condition though thats a great purchase. LO3s recieve alot of hate, most of which they deserve, but its certainly not as bad as it sounds. Not to mention they are like the energizer bunny, run forever.

 

I second that, they do go forever. There is a lot you can do cheaply to pick up performance, but you'll never hang with the 383's and 400's but I have seen countless 305's mop up 350's with just bolt ons. If you are looking for a car that protect you, even though you walk through the valley of rice, have no fear becasue torque art with thou.

I.e. Waste any rice burner, but in the world of real cars its the middle of the road. Mild performance, awesome life span, cool car...

 

There is a lot of info on this forum for what to do to get more HP out of the LO3. But, I agree with above, this car lasts forever. My wife drives this car every day and it is very dependable and fun to drive and won't get you into too much trouble with the law.

 

Probably two of the easiest are going with a K&N open element air cleaner and a good flowing muffler like a flowmaster. If emissions are'nt a concern in your area you can eliminate some of the emissions controlls, like smog pump and knock out your cat. There are some tech articles here that deal with mods to squeeze as much HP as possible out of your TBI. With everything I've done I'm pushing 200HP. I'm also in the process of doing a TPI conversion. That alone can give you a 50 to 60 HP gain with no other mods! I hope this helps. Good luck!
BTW; my 92 RS Heritage Edition has 169863 miles on it, and other than the transmission, it's still running strong!

 

I would def tell you to do the open element OMG it makes a difference. What has been said though in many other posts i will say agian because im going through this journey on my 92 rs. 350 SWAP!! Not hard really just the tuning side everyone here is very helpful and you can pick up a nice base for your power plant from a junkyard for about 250-300 bucks. but if you dont want to swap then atleast get into tuning/chip burning, and basically all the ultimate tbi mods, which includes things like exhaust and fuel intake and what not

 

As far as I know with the Camaro so far everything I hear is replace the exhaust system first because they are horrible and I have learned many other things on this post about modding a TBI engine....just keep your eyes open.

 

Then he WAKES from his DREAMS.

 

Your right Fast355! I forgot about the TBI's crummy heads! With the stock TBI heads, a TPI conversion will probably net between 30 to 40 horse. There are plenty more mods to squeeze about another 20 horse even with the TBI heads. Such as a good muffler, no cat, cold or ram air induction, TB bypass, TB air foil, performance chip, etc..

 

If you look at it at face value, the 190 HP TPI 305 and the 170 HP TBI 305 are closest in composition. The difference in the two is Heads, Intake, and Tuning. That is less than 20 HP divided between three things.

My latest TPI swap was with TPI heads on a 305 with a LT1 cam. Here are the results, see for yourself.

This was with late model Vortec Express Van electronics using Sequential injection as well.

https://www.thirdgen.org/forums/tbi/...03-update.html

 

I didn't know the exhaust was identical. If the exhaust wasn't identical, then there is 20 hp divided among four items.... and IMO the exhaust is worth the most.

Walker's replacement parts website shows slightly different exh system parts for the E (VIN code) TBI 305 vs the 305 TPI engine.. especially the Ypipe size, intermediate pipe pn, and tail pipe sizes. The TPI gets the bigger ones (duh):

http://www.walkerexhaust.com/catalog...letypescrn.asp

I don't know if the stock GM stuff went the same way, but it wouldn't surprise me.

TPI excels at mid range torque production, either stock TPI compared against stock TBI, or in a heavily modified series of tests:

https://www.thirdgen.org/forums/tpi/...feb-super.html

Stock TPI (410hp, 500lb-ft)
Edelbrock High-Flo (431hp, 501lb-ft)
Extrude Hone base & LTR (451hp, 534lb-ft)
TPIS Big Mouth System (460hp, 534lb-ft)
ASM Siamesed Runners (464hp, 510lb-ft)
SLP T-Ram (466hp, 495lb-ft)
Accel SR (480hp, 506lb-ft)
Holley single plane (493hp, 480lb-ft)
HSR (501hp, 493lb-ft)
MR (505hp, 471lb-ft)

The engine was a 10:1 383 with Trick Flow heads and the Comp XR288HR (236/242, .520/.540), i.e. the same heads/cam used on all of the above.

OTOH that same test series showed that small diameter runners are not helpful in making peak power... with the Holley single plane intake (essentially a carb-type intake like the one used on TBI) together with a conventional 4-bore throttle beating all the TPI intakes in hp, and losing only to the HSR and Miniram.

At lower engine power outputs, as in stock or slightly modified street engines, the cam and exhaust have more of an effect on power output than the intake does.