Cheapest/Easiest HP Mods????
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Junior Member
Joined: Feb 2009
Posts: 1
Likes: 0
Car: 91 Z28
Engine: 305 TPI
Transmission: 700R4
Axle/Gears: 2:73
Cheapest/Easiest HP Mods????
Need some ideas on what I can do as far as the Cheapest and Easiest horsepower mods. Currently a bone stock 91' 305 TPI automatic. Trying to avoid cam changes/Engine swaps etc...
I know some of you have some great ideas and fixes so I appreciate any thoughts on this.
Thanks in advance.
I know some of you have some great ideas and fixes so I appreciate any thoughts on this.
Thanks in advance.
Senior Member
iTrader: (8)
Joined: Aug 2007
Posts: 1,341
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From: Southern Wisconsin
Car: 1988 Camaro
Engine: 383 Stroker
Transmission: Probuilt 700 R4
Axle/Gears: 3.73
Re: Cheapest/Easiest HP Mods????
no need for a true dual exhaust, just a waste in my opinion. But a good set of headers along with a 3 inch exhaust will flow plenty for your application. Then do a complete tune up, all fluids etc. Then maybe heads a higher rear end gear like 3.42 or 3.73. That will wake it up a bit.
Senior Member
Joined: May 2008
Posts: 722
Likes: 0
From: SF bay area
Car: 86 Camaro iroc-z28
Engine: 305 TPI
Transmission: 700R4
Axle/Gears: 3.42 Posi
Re: Cheapest/Easiest HP Mods????
i saw a great motto at a shop once. it said, "Good work aint cheap, cheap work aint good"
and thats basically the same concept. cheap mods like, descreening your MAF sensor(doesnt apply to you because you have SD), throttle body air foil, throttle body coolant bypass, aftermarket ship, those are little mods and wont increase horsepower much if at all. if your looking for substantial gains in horsepower, you going to have to think of big mods like headers and y pipe, cam and heads, nitrous, ported intake, catback exhaust. these mods can get pricey, but youll love the fact that these will give you significant gains as opposed to putting a throttle body air foil on , or bypassing the coolant, and wondering if your car is actually any faster.
remember, its not how fast you want to go, its how fast can you afford to go lol
and thats basically the same concept. cheap mods like, descreening your MAF sensor(doesnt apply to you because you have SD), throttle body air foil, throttle body coolant bypass, aftermarket ship, those are little mods and wont increase horsepower much if at all. if your looking for substantial gains in horsepower, you going to have to think of big mods like headers and y pipe, cam and heads, nitrous, ported intake, catback exhaust. these mods can get pricey, but youll love the fact that these will give you significant gains as opposed to putting a throttle body air foil on , or bypassing the coolant, and wondering if your car is actually any faster.
remember, its not how fast you want to go, its how fast can you afford to go lol
Last edited by gurkgurkgurk; Sep 3, 2009 at 01:03 AM.
Junior Member
Joined: Sep 2009
Posts: 17
Likes: 0
From: Akron, IN
Car: 87 Trans Am GTA
Engine: 350 TPI
Transmission: 700 R4
Re: Cheapest/Easiest HP Mods????
i saw a great motto at a shop once. it said, "Good work aint cheap, cheap work aint good"
and thats basically the same concept. cheap mods like, descreening your MAF sensor(doesnt apply to you because you have SD), throttle body air foil, throttle body coolant bypass, aftermarket ship, those are little mods and wont increase horsepower much if at all. if your looking for substantial gains in horsepower, you going to have to think of big mods like headers and y pipe, cam and heads, nitrous, ported intake, catback exhaust. these mods can get pricey, but youll the fact that these will give you significant gains as opposed to putting a throttle body air foil on , or bypassing the coolant, and wondering if your car is actually any faster.
remember, its not how fast you want to go, its how fast can you afford to go lol
and thats basically the same concept. cheap mods like, descreening your MAF sensor(doesnt apply to you because you have SD), throttle body air foil, throttle body coolant bypass, aftermarket ship, those are little mods and wont increase horsepower much if at all. if your looking for substantial gains in horsepower, you going to have to think of big mods like headers and y pipe, cam and heads, nitrous, ported intake, catback exhaust. these mods can get pricey, but youll the fact that these will give you significant gains as opposed to putting a throttle body air foil on , or bypassing the coolant, and wondering if your car is actually any faster.
remember, its not how fast you want to go, its how fast can you afford to go lol
i would listen to this guy lol nicely said
Supreme Member

Joined: Nov 2008
Posts: 1,545
Likes: 10
From: South Carolina
Car: 85 2M6, 87 'Bird 88 'burb
Engine: LX9, LG4, L05
Transmission: F23, 700r4, 700R4
Axle/Gears: 3.63, 2.73, 4.10
Re: Cheapest/Easiest HP Mods????
I saw something similar to this at a transmission shop, you can have your work done following any two of these three parameters:
Cheap
Fast
Good
you can have it good and cheap, but it won't be fast.
you can have it fast and cheap, but it won't be good.
or, you can have it fast and good, but it won't be cheap!
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Junior Member
Joined: Aug 2009
Posts: 35
Likes: 0
From: WBL, MN
Car: 1987 Firebird Formula
Engine: 305 w/Edelbrock carb
Transmission: 5 speed manual
Re: Cheapest/Easiest HP Mods????
I'm not sure if this holds true or not, but I've heard no A/C, no emissions like EGR valve, can add up. My car came without this stuff. I think it was my EGR valve my neighbor/mechanic told me was worth 10hp. Listen to these other people though, there's not much you can do to get a "holy **** this is way faster than before" feeling. A new rear end is something I'm trying to do
Senior Member
Joined: May 2008
Posts: 722
Likes: 0
From: SF bay area
Car: 86 Camaro iroc-z28
Engine: 305 TPI
Transmission: 700R4
Axle/Gears: 3.42 Posi
Re: Cheapest/Easiest HP Mods????
I'm not sure if this holds true or not, but I've heard no A/C, no emissions like EGR valve, can add up. My car came without this stuff. I think it was my EGR valve my neighbor/mechanic told me was worth 10hp. Listen to these other people though, there's not much you can do to get a "holy **** this is way faster than before" feeling. A new rear end is something I'm trying to do
on your carbed engine the egr doesnt have much use except for emissions, on the tpi cars, its only there for emissions and will make your car not pass smog. aswell as throw a check engine light.
id say something that is worth doing is putting rear gears, or even a shift kit. the shift kit makes the illusion of horsepower, but it makes your car really feel like a sportscar
Joined: May 2009
Posts: 562
Likes: 27
From: Buffalo, NY
Car: 92 Z28
Engine: LS3
Transmission: TR6060
Axle/Gears: Strange S60 3.73
Re: Cheapest/Easiest HP Mods????
Welcome aboard.
I think removing EGR on TPI cars hurts performance since ECU is programmed to read measurements from the O2 sensor. If you remove EGR, ECU must be modified or ECU will retard engine due to wrong O2 readings. There are a lot of threads of making more HP with a 305 TPI (some below). Can you tell us what engine you have? The eigth digit in the VIN will tell http://www.chevy-camaro.com/chevy-ca...-third-gen.asp We can them see what things will help you.
Some engines came with a weak "peanut cam" so swapping one could help you alot. Would be around $100 for cam. I second a single 3" exhaust with decent aftermarket headers and a good Y-pipe. Exhaust would probably cost around $1,000. Stock exhaust is one of the most restrictive components. You can also port the intake plenum and runners. Porting won't gain huge results but will help. Switching rear end gears to 3.23 or 3.42 will help a lot. I believe you have a MAP engine sensor. If you increase power too much from stock you will have to get your ECU reprogrammed to make engine run its best.
How much are you looking to spend. Maybe you can upgrade things in stages. Any pics of your ride?
1) headers with Y-pipe & 3" exhaust
2) port intake
3) replace cam
4) replace gears
5) replace heads or upgrade existing (may not be worth it $$ to you)
https://www.thirdgen.org/forums/tpi/...-upgrades.html
https://www.thirdgen.org/forums/tpi/...-upgrades.html
I think removing EGR on TPI cars hurts performance since ECU is programmed to read measurements from the O2 sensor. If you remove EGR, ECU must be modified or ECU will retard engine due to wrong O2 readings. There are a lot of threads of making more HP with a 305 TPI (some below). Can you tell us what engine you have? The eigth digit in the VIN will tell http://www.chevy-camaro.com/chevy-ca...-third-gen.asp We can them see what things will help you.
Some engines came with a weak "peanut cam" so swapping one could help you alot. Would be around $100 for cam. I second a single 3" exhaust with decent aftermarket headers and a good Y-pipe. Exhaust would probably cost around $1,000. Stock exhaust is one of the most restrictive components. You can also port the intake plenum and runners. Porting won't gain huge results but will help. Switching rear end gears to 3.23 or 3.42 will help a lot. I believe you have a MAP engine sensor. If you increase power too much from stock you will have to get your ECU reprogrammed to make engine run its best.
How much are you looking to spend. Maybe you can upgrade things in stages. Any pics of your ride?
1) headers with Y-pipe & 3" exhaust
2) port intake
3) replace cam
4) replace gears
5) replace heads or upgrade existing (may not be worth it $$ to you)
https://www.thirdgen.org/forums/tpi/...-upgrades.html
https://www.thirdgen.org/forums/tpi/...-upgrades.html
Junior Member
Joined: May 2006
Posts: 98
Likes: 1
From: Gloucester Co. N.J.
Car: 86 IROC
Engine: 350 Miniram
Transmission: T5
Axle/Gears: 3.73
Re: Cheapest/Easiest HP Mods????
Open up the area under your air filters, Advance timing 4*, muffler, fuel pressure regulator, shift kit, 1.6 rockers (lazy man's cam swap. Gives you .030 more lift).
When you get some cash: Exhaust and headers, find yourself a ported base and runners then port the plenum, 3.42's with a real posi, prom tuning, sub-frame connectors, drag radials, 100 shot.
When you want to go fast: Bigger motor with heads and cam and a real intake, more prom tuning, and more nitrous.
When you get some cash: Exhaust and headers, find yourself a ported base and runners then port the plenum, 3.42's with a real posi, prom tuning, sub-frame connectors, drag radials, 100 shot.
When you want to go fast: Bigger motor with heads and cam and a real intake, more prom tuning, and more nitrous.
Junior Member
Joined: Aug 2009
Posts: 1
Likes: 0
From: phx
Car: '88 iroc
Engine: 305 tpi
Transmission: t-5
Re: Cheapest/Easiest HP Mods????
i'm kind of in the same boat as nepatriots. i have flowmasters and now i want headers. how much hp increase would you guys assume i'll get from a good set of headers? 305 tpi bored .030 over, msd ignition, k&n. i'm thinking i've probably got about 240hp now. what will headers do?
Supreme Member
Joined: Jun 2006
Posts: 2,199
Likes: 1
From: West-Central
Car: 91 Trans am
Engine: built 360 TBI
Transmission: built 700r4
Axle/Gears: 10bolt/3.23
Re: Cheapest/Easiest HP Mods????
Junior Member
Joined: Sep 2008
Posts: 15
Likes: 0
From: MV, OH
Car: 87 IROCZ
Engine: 305 TPI
Transmission: 700R4 shift kit, corvette servo...
Axle/Gears: 26 spline 4.10 mini spool
Re: Cheapest/Easiest HP Mods????
what is the biggest cam i can use with a stock 87 305 tpi? and also i read it befor but cant find it again................ if i get an adjustable fuel pressure regulator, how much pressure should i run with stock injectors?
Supreme Member
Joined: Mar 2009
Posts: 1,402
Likes: 3
From: Sussex County, NJ
Car: 1994 Z28
Engine: 355 LT1
Transmission: T56
Axle/Gears: 3.42
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