where to start for HP mods?
08-14-2017, 06:35 PM
#1
6th Gear
Thread Starter
Member Since: Jun 2017
Location: Fort Myers Florida
Posts: 6
Likes: 0
Received 0 Likes
on
0 Posts
where to start for HP mods?
Hello I want to start adding HP to my 89 vette, where do i start? i do not have a lot of money to be throwing into it , and may never have but when i do get lets says and extra 600 to 800 dollars here and there, Christmas or birthday money from relatives , should i go for exhaust first? if so which are the Better choices out there beside magnaflow or does it make a difference? as long as it's "cat back " right? if not exhaust then what would be the best first steps to take? and if this has been posted before i apologize for not finding it .
thanks for the help
thanks for the help
Last edited by DC3shadow; 08-14-2017 at 06:38 PM.
08-14-2017, 06:47 PM
#3
Save up a few thousand dollars. Then you can at least make some complimentary mods.
Or sell and then add the thousands saved to a newer vette.
If it is for feeling like you made mods that is one thing, but if you really want to have a fun car it will take Many thousands of dollars to make it fast.
Even adding 100hp to it will still not feel like a 400+ hp car, so you need to consider that.
Do some math in dyno threads and add up the parts cost to add a true 100hp to your car.
Otherwise just enjoy buying parts and tinkering with it.
Or sell and then add the thousands saved to a newer vette.
If it is for feeling like you made mods that is one thing, but if you really want to have a fun car it will take Many thousands of dollars to make it fast.
Even adding 100hp to it will still not feel like a 400+ hp car, so you need to consider that.
Do some math in dyno threads and add up the parts cost to add a true 100hp to your car.
Otherwise just enjoy buying parts and tinkering with it.
08-14-2017, 08:03 PM
#4
Team Owner
Member Since: Oct 2004
Location: altered state
Posts: 81,242
Received 3,043 Likes
on
2,602 Posts
St. Jude Donor '05
most cars especially a C4 cost a lot to gain small amounts of powerIf youre dead set on it try used headers, get rid of the mufflers altogether, look for deals on used intakes, etc
If you want a ton more power not sure id even get started til you can save and really go all out or just buy a better platform altogether.
08-14-2017, 08:13 PM
#5
Hello I want to start adding HP to my 89 vette, where do i start? i do not have a lot of money to be throwing into it , and may never have but when i do get lets says and extra 600 to 800 dollars here and there, Christmas or birthday money from relatives , should i go for exhaust first? if so which are the Better choices out there beside magnaflow or does it make a difference? as long as it's "cat back " right? if not exhaust then what would be the best first steps to take? and if this has been posted before i apologize for not finding it .
thanks for the help
thanks for the help
08-14-2017, 10:19 PM
#6
Zen Vet Master Level VII
You have a pretty tight budget, so...
1) Rear axel gear. Nuff said. This IS the modification. $300ish.
2) Exhaust. Remove the "pre cats" and either eliminate/get a performance catalysis (if required) and leave the factory mufflers. They really don't flow that bad and will sound better and give you a seat in the pants. $350ish (if you need to get the cat, less if not about 150)
3) A super squared away tune up. $150
For your budget, this is about max. You will really wake up the 89 with these changes.
1) Rear axel gear. Nuff said. This IS the modification. $300ish.
2) Exhaust. Remove the "pre cats" and either eliminate/get a performance catalysis (if required) and leave the factory mufflers. They really don't flow that bad and will sound better and give you a seat in the pants. $350ish (if you need to get the cat, less if not about 150)
3) A super squared away tune up. $150
For your budget, this is about max. You will really wake up the 89 with these changes.
08-14-2017, 11:59 PM
#7
6th Gear
Thread Starter
Member Since: Jun 2017
Location: Fort Myers Florida
Posts: 6
Likes: 0
Received 0 Likes
on
0 Posts
I do not really want to sell the car other than not enough HP i really enjoy drving it, if i could get it up to 300 hp i would be very happy with it,
Save up a few thousand dollars. Then you can at least make some complimentary mods.
Or sell and then add the thousands saved to a newer vette.
If it is for feeling like you made mods that is one thing, but if you really want to have a fun car it will take Many thousands of dollars to make it fast.
Even adding 100hp to it will still not feel like a 400+ hp car, so you need to consider that.
Do some math in dyno threads and add up the parts cost to add a true 100hp to your car.
Otherwise just enjoy buying parts and tinkering with it.
Or sell and then add the thousands saved to a newer vette.
If it is for feeling like you made mods that is one thing, but if you really want to have a fun car it will take Many thousands of dollars to make it fast.
Even adding 100hp to it will still not feel like a 400+ hp car, so you need to consider that.
Do some math in dyno threads and add up the parts cost to add a true 100hp to your car.
Otherwise just enjoy buying parts and tinkering with it.
08-15-2017, 01:47 AM
#8
Team Owner
Member Since: Sep 2003
Location: Freedom is never more than one generation away from extinction.
Posts: 20,161
Received 640 Likes
on
444 Posts
St. Jude '03-'04-'05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15-'16-'17-'18-‘19-'20-'21-'22-'23-'24
Swap in a good cam.
Best place to start for maximum smiles.
0.02
Best place to start for maximum smiles.
0.02
08-15-2017, 04:30 AM
#9
That's like the guy who said If I could just make an extra hundred bucks a month I'd be happy. If you are looking for more HP you won't stop or be happy at 300. You know I know it and the whole forum knows it. We are all too similar to pull that bs comment.
08-15-2017, 11:08 AM
#10
Team Owner
Member Since: Sep 2001
Location: Athens AL
Posts: 59,654
Received 1,401 Likes
on
1,017 Posts
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Performance gear axle? in an 89? No. Do not waste your money there. What the L98 needs is not what the LT1 cars need.
$600-800 at a time is what I started on, but you need a plan. Come up with a power goal and decide how you want the car to drive: mostly top end? high revver? torquey down low? torque plus some midrange power? These are characteristics that you must decide on before you go into things like intake/heads/camshaft, otherwise you'll be spending the money twice.
If you don't have a plan, HP goal, 1/4mi ET goal, or something like that, then stop now, do not start spending money until you do. Spend your time reading and researching.
If you want my opinion on the best place to start, its exhaust. The L98 responds really well to changes here. You must decide on the noise level you want, as most catbacks basically all give about 10-15hp and vary markedly in sound. Do you need to keep the precats and main cat? This must be answered before you pick headers, which would be next on my list (Hooker, TPiS). Together you could get over 30hp from just exhaust changes, and they'll work with whatever engine changes you do later.
Your heads are fine, leave them be for now. You have D-port 113 heads.
1.6 RR are a fine mod for $250 that will carry over to whatever you decide to do with the rest of the engine later.
If its an automatic, then a slightly higher stall TC would help you. 89 has a wimpy 1500-1700 stall, you will want more like 2000-2200 for a stock or near-stock engine.
Just those things will get you started, but formulate your plan before doing anything else.
$600-800 at a time is what I started on, but you need a plan. Come up with a power goal and decide how you want the car to drive: mostly top end? high revver? torquey down low? torque plus some midrange power? These are characteristics that you must decide on before you go into things like intake/heads/camshaft, otherwise you'll be spending the money twice.
If you don't have a plan, HP goal, 1/4mi ET goal, or something like that, then stop now, do not start spending money until you do. Spend your time reading and researching.
If you want my opinion on the best place to start, its exhaust. The L98 responds really well to changes here. You must decide on the noise level you want, as most catbacks basically all give about 10-15hp and vary markedly in sound. Do you need to keep the precats and main cat? This must be answered before you pick headers, which would be next on my list (Hooker, TPiS). Together you could get over 30hp from just exhaust changes, and they'll work with whatever engine changes you do later.
Your heads are fine, leave them be for now. You have D-port 113 heads.
1.6 RR are a fine mod for $250 that will carry over to whatever you decide to do with the rest of the engine later.
If its an automatic, then a slightly higher stall TC would help you. 89 has a wimpy 1500-1700 stall, you will want more like 2000-2200 for a stock or near-stock engine.
Just those things will get you started, but formulate your plan before doing anything else.
Last edited by vader86; 08-15-2017 at 11:10 AM.
08-15-2017, 12:09 PM
#11
6th Gear
Thread Starter
Member Since: Jun 2017
Location: Fort Myers Florida
Posts: 6
Likes: 0
Received 0 Likes
on
0 Posts
thank you
even small changes at a time is better than nothing at all yes its an automatic, i got what i could afford at the time,
and was closest to me, i was depending on friends to drive me to car lots to look at cars, I saw this low mileage corvette, I like all muscle or sports cars, yes some more than others LOL my buddy suggested getting it and adding mods to it one part at a time, i will look into exhaust systems thanks again for your help and thanks to everyone for your help and information.
and was closest to me, i was depending on friends to drive me to car lots to look at cars, I saw this low mileage corvette, I like all muscle or sports cars, yes some more than others LOL my buddy suggested getting it and adding mods to it one part at a time, i will look into exhaust systems thanks again for your help and thanks to everyone for your help and information.
Performance gear axle? in an 89? No. Do not waste your money there. What the L98 needs is not what the LT1 cars need.
$600-800 at a time is what I started on, but you need a plan. Come up with a power goal and decide how you want the car to drive: mostly top end? high revver? torquey down low? torque plus some midrange power? These are characteristics that you must decide on before you go into things like intake/heads/camshaft, otherwise you'll be spending the money twice.
If you don't have a plan, HP goal, 1/4mi ET goal, or something like that, then stop now, do not start spending money until you do. Spend your time reading and researching.
If you want my opinion on the best place to start, its exhaust. The L98 responds really well to changes here. You must decide on the noise level you want, as most catbacks basically all give about 10-15hp and vary markedly in sound. Do you need to keep the precats and main cat? This must be answered before you pick headers, which would be next on my list (Hooker, TPiS). Together you could get over 30hp from just exhaust changes, and they'll work with whatever engine changes you do later.
Your heads are fine, leave them be for now. You have D-port 113 heads.
1.6 RR are a fine mod for $250 that will carry over to whatever you decide to do with the rest of the engine later.
If its an automatic, then a slightly higher stall TC would help you. 89 has a wimpy 1500-1700 stall, you will want more like 2000-2200 for a stock or near-stock engine.
Just those things will get you started, but formulate your plan before doing anything else.
$600-800 at a time is what I started on, but you need a plan. Come up with a power goal and decide how you want the car to drive: mostly top end? high revver? torquey down low? torque plus some midrange power? These are characteristics that you must decide on before you go into things like intake/heads/camshaft, otherwise you'll be spending the money twice.
If you don't have a plan, HP goal, 1/4mi ET goal, or something like that, then stop now, do not start spending money until you do. Spend your time reading and researching.
If you want my opinion on the best place to start, its exhaust. The L98 responds really well to changes here. You must decide on the noise level you want, as most catbacks basically all give about 10-15hp and vary markedly in sound. Do you need to keep the precats and main cat? This must be answered before you pick headers, which would be next on my list (Hooker, TPiS). Together you could get over 30hp from just exhaust changes, and they'll work with whatever engine changes you do later.
Your heads are fine, leave them be for now. You have D-port 113 heads.
1.6 RR are a fine mod for $250 that will carry over to whatever you decide to do with the rest of the engine later.
If its an automatic, then a slightly higher stall TC would help you. 89 has a wimpy 1500-1700 stall, you will want more like 2000-2200 for a stock or near-stock engine.
Just those things will get you started, but formulate your plan before doing anything else.
08-15-2017, 12:10 PM
#12
Advanced
Performance gear axle? in an 89? No. Do not waste your money there. What the L98 needs is not what the LT1 cars need.
$600-800 at a time is what I started on, but you need a plan. Come up with a power goal and decide how you want the car to drive: mostly top end? high revver? torquey down low? torque plus some midrange power? These are characteristics that you must decide on before you go into things like intake/heads/camshaft, otherwise you'll be spending the money twice.
If you don't have a plan, HP goal, 1/4mi ET goal, or something like that, then stop now, do not start spending money until you do. Spend your time reading and researching.
If you want my opinion on the best place to start, its exhaust. The L98 responds really well to changes here. You must decide on the noise level you want, as most catbacks basically all give about 10-15hp and vary markedly in sound. Do you need to keep the precats and main cat? This must be answered before you pick headers, which would be next on my list (Hooker, TPiS). Together you could get over 30hp from just exhaust changes, and they'll work with whatever engine changes you do later.
Your heads are fine, leave them be for now. You have D-port 113 heads.
1.6 RR are a fine mod for $250 that will carry over to whatever you decide to do with the rest of the engine later.
If its an automatic, then a slightly higher stall TC would help you. 89 has a wimpy 1500-1700 stall, you will want more like 2000-2200 for a stock or near-stock engine.
Just those things will get you started, but formulate your plan before doing anything else.
$600-800 at a time is what I started on, but you need a plan. Come up with a power goal and decide how you want the car to drive: mostly top end? high revver? torquey down low? torque plus some midrange power? These are characteristics that you must decide on before you go into things like intake/heads/camshaft, otherwise you'll be spending the money twice.
If you don't have a plan, HP goal, 1/4mi ET goal, or something like that, then stop now, do not start spending money until you do. Spend your time reading and researching.
If you want my opinion on the best place to start, its exhaust. The L98 responds really well to changes here. You must decide on the noise level you want, as most catbacks basically all give about 10-15hp and vary markedly in sound. Do you need to keep the precats and main cat? This must be answered before you pick headers, which would be next on my list (Hooker, TPiS). Together you could get over 30hp from just exhaust changes, and they'll work with whatever engine changes you do later.
Your heads are fine, leave them be for now. You have D-port 113 heads.
1.6 RR are a fine mod for $250 that will carry over to whatever you decide to do with the rest of the engine later.
If its an automatic, then a slightly higher stall TC would help you. 89 has a wimpy 1500-1700 stall, you will want more like 2000-2200 for a stock or near-stock engine.
Just those things will get you started, but formulate your plan before doing anything else.
Don
08-15-2017, 01:15 PM
#13
Safety Car
How to boost horsepower, Cheaply....
First I agree with the ideas mentioning to open up the exhaust and make it more freely flow. I have a 1988 Coupe with the automatic. I have a Allen's Stainless Exhaust system on my car, I bought it at Corvettes @ Carlisle. I also changed the air filter to a K&N filter. Driving at 60 mph on the interstates I can average 30 mpg with my C4 and that is in the air conditioned comfort with a nice stereo playing.
Getting rid of the two "Pre-catalytic" Converters and changing the main converter to a "high flow" model really helps. My system was a cat-back system and it sounds awesome without the annoying drone you will get with some brands at speed. Be careful, when you change the exhaust to an aftermarket system you will potentially introduce a lot of noise into your car. Driving in a noisy car isn't much fun, My cousin had a 1967 C2 with side pipes and I couldn't stand it after half an hour at highway speeds.
That brings up another point, car shows like Corvettes @ Carlisle attract a lot of people (40,000-50,000) and the sale pricing alone can save you a bunch of money.
I have been going since the early 90's as I live 100 miles from Carlisle. You are in Fort Myers which is kind of a long ride to Carlisle, PA (1132 miles or 17.5 hours of highway driving). Maybe drive up one year and go to Corvettes @ Carlisle. I have friends who come up from Key West every year in a 1958 Corvette. There are probably Corvette gatherings in Florida but none as big as Bloomington or Carlisle. Corvettes @ Carlisle is held every August on the third weekend of the month.
At Carlisle I bought my Cat-back exhaust system and it knocked off a couple hundred bucks between shipping and the sale price. You used to be able to find anything you needed for a Corvette but now that the C4's are getting older the parts are becoming less and less available. Why I don't know, they sell a ton of C3 parts and those are even older.
I have only one suggestion which I try to live by, "If it isn't broken, don't fix it". Yes when you first get a Corvette a lot of people want to make it the fastest car they have ever had. The engineers at GM were a pretty smart group and these cars are well engineered from the factory. Drive the car and "learn" the car before you open the checkbook up.
My advice is simple, make the car safe to drive and then work on performance.
Unless you are very mechanically inclined these are expensive cars to own and maintain. Trying to get more power out of the original L98 is a daunting task. It is thirty plus year old technology but when it all works the way it was designed, it is awesome!
Welcome to the Corvette Forum and to the Corvette World in general! I wish you all the success possible!
Getting rid of the two "Pre-catalytic" Converters and changing the main converter to a "high flow" model really helps. My system was a cat-back system and it sounds awesome without the annoying drone you will get with some brands at speed. Be careful, when you change the exhaust to an aftermarket system you will potentially introduce a lot of noise into your car. Driving in a noisy car isn't much fun, My cousin had a 1967 C2 with side pipes and I couldn't stand it after half an hour at highway speeds.
That brings up another point, car shows like Corvettes @ Carlisle attract a lot of people (40,000-50,000) and the sale pricing alone can save you a bunch of money.
I have been going since the early 90's as I live 100 miles from Carlisle. You are in Fort Myers which is kind of a long ride to Carlisle, PA (1132 miles or 17.5 hours of highway driving). Maybe drive up one year and go to Corvettes @ Carlisle. I have friends who come up from Key West every year in a 1958 Corvette. There are probably Corvette gatherings in Florida but none as big as Bloomington or Carlisle. Corvettes @ Carlisle is held every August on the third weekend of the month.
At Carlisle I bought my Cat-back exhaust system and it knocked off a couple hundred bucks between shipping and the sale price. You used to be able to find anything you needed for a Corvette but now that the C4's are getting older the parts are becoming less and less available. Why I don't know, they sell a ton of C3 parts and those are even older.
I have only one suggestion which I try to live by, "If it isn't broken, don't fix it". Yes when you first get a Corvette a lot of people want to make it the fastest car they have ever had. The engineers at GM were a pretty smart group and these cars are well engineered from the factory. Drive the car and "learn" the car before you open the checkbook up.
My advice is simple, make the car safe to drive and then work on performance.
Unless you are very mechanically inclined these are expensive cars to own and maintain. Trying to get more power out of the original L98 is a daunting task. It is thirty plus year old technology but when it all works the way it was designed, it is awesome!
Welcome to the Corvette Forum and to the Corvette World in general! I wish you all the success possible!
08-15-2017, 05:29 PM
#14
08-15-2017, 06:13 PM
#15
Le Mans Master
Member Since: Dec 2005
Location: Where Woke Goes to Die
Posts: 8,194
Received 615 Likes
on
431 Posts
When youre modding any Internal Combustion Engine, remember its really a big air pump. Air in, air out. In between that, fuel metering and ignition timing are part of the dance.
A huge cold air intake will suck in more air, but that same air will need to be expelled. Think of things on a systematic basis... Try addressing one system at a time... If I were going to do exhaust work, Id save my pennies and buy from the headers all the way to the tail pipes and have that finished.
Next, I would work on the air into the engine... What will increase this? A larger air filtration system with little restriction. What else in the system would I address? Probably think about the air intake system next, porting of the intake, maybe matching the lower half to the runners..... or as mentioned, swapping the whole intake for a higher performance version.
Along with this, the cam shaft is at the heart of air in and air out... it opens the valves to accept the air in and out... higher lift cam = the valve opening further to accept and expel more air.
Heads and compression play a big part in the air flow of the engine as well.... Better flowing heads with larger valves move more air in and out of the engine....
This is a simple way to look at things.... but we can dive much further into things when looking at parts of the car systematically... Back to the cam shaft.... that plays along with the torque converter rpm lockup as well as the rear end gearing... Everything must flow together and be matched as closely as possible in terms of where your power band is most targeted.
My advice to you is, first, do a good tune up with good quality parts and first see if you can get the car in stock form to perform as close to peak as possible. I'm sure you will see improvements doing just this alone. Then decide where you would like to see gains.
As someone else also said, make damn sure the car is safe and stops like it should too. There are many performance upgrades that can be advantageous to the braking system as well as the engine, and suspension.
A huge cold air intake will suck in more air, but that same air will need to be expelled. Think of things on a systematic basis... Try addressing one system at a time... If I were going to do exhaust work, Id save my pennies and buy from the headers all the way to the tail pipes and have that finished.
Next, I would work on the air into the engine... What will increase this? A larger air filtration system with little restriction. What else in the system would I address? Probably think about the air intake system next, porting of the intake, maybe matching the lower half to the runners..... or as mentioned, swapping the whole intake for a higher performance version.
Along with this, the cam shaft is at the heart of air in and air out... it opens the valves to accept the air in and out... higher lift cam = the valve opening further to accept and expel more air.
Heads and compression play a big part in the air flow of the engine as well.... Better flowing heads with larger valves move more air in and out of the engine....
This is a simple way to look at things.... but we can dive much further into things when looking at parts of the car systematically... Back to the cam shaft.... that plays along with the torque converter rpm lockup as well as the rear end gearing... Everything must flow together and be matched as closely as possible in terms of where your power band is most targeted.
My advice to you is, first, do a good tune up with good quality parts and first see if you can get the car in stock form to perform as close to peak as possible. I'm sure you will see improvements doing just this alone. Then decide where you would like to see gains.
As someone else also said, make damn sure the car is safe and stops like it should too. There are many performance upgrades that can be advantageous to the braking system as well as the engine, and suspension.
Last edited by 81c3; 08-15-2017 at 06:15 PM.
