Mild Horsepower Gain
Thread Starter
Melting Slicks
Joined: Oct 2005
Posts: 2,526
Likes: 99
From: Apache Junction, Arizona
St. Jude Donor '12-'13-'14-'15-'16
Mild Horsepower Gain
Last month I purchased an 87 Roadster with 50K on it. Auto.
This past weekend I added the following.
1.SLP Performance Cold Air Intake
2. Throttle Body Flow Booster
3. Power Coupler
4. DynoMax High Performance Mufflers with Y- Pipe.
All the above from Mid America. Says I gained over 45HP.
Car does run alot better, more responsive and gets better gas mileage.
Feels like maybe a 20hp gain at most.
My next phase is Air pump replacement pulley kit and headers.
Is the next phase worth the bang for the buck.
Love driving the C4 it is sooooo much better than my C3
This past weekend I added the following.
1.SLP Performance Cold Air Intake
2. Throttle Body Flow Booster
3. Power Coupler
4. DynoMax High Performance Mufflers with Y- Pipe.
All the above from Mid America. Says I gained over 45HP.
Car does run alot better, more responsive and gets better gas mileage.
Feels like maybe a 20hp gain at most.
My next phase is Air pump replacement pulley kit and headers.
Is the next phase worth the bang for the buck.
Love driving the C4 it is sooooo much better than my C3
Instructor
Joined: Oct 2005
Posts: 184
Likes: 0
From: Woodmere New York
let me start by saying that I am no expert...there are many guys out here on the forum that really know their sh--...but, I have become fairly knowledgeable through listening to others...
the first thing that must be changed in our C4's is the intake..it chokes the crap out of the engine..it was designed for the 305 motor...not a 350....depending what your plan is with the car (and by that I am referring to what other mods you plan), you can either bore out the tpi system or go with a superram or miniram setup...
the exhaust is a good call as well...the headers are very restrictive....I definitely felt a lil' something when I changed my exhaust to a catback borla early on...I added a random tech cat...not sure if it really did much...probably a solid 15 hp.....
as I have learned the hard way, stay away from most bolt on stuff in midamerica, ecklers, or the like...the only real horsepower costs $$...save and throw it into the heads (great place to get power) and the engine....
the first thing that must be changed in our C4's is the intake..it chokes the crap out of the engine..it was designed for the 305 motor...not a 350....depending what your plan is with the car (and by that I am referring to what other mods you plan), you can either bore out the tpi system or go with a superram or miniram setup...
the exhaust is a good call as well...the headers are very restrictive....I definitely felt a lil' something when I changed my exhaust to a catback borla early on...I added a random tech cat...not sure if it really did much...probably a solid 15 hp.....
as I have learned the hard way, stay away from most bolt on stuff in midamerica, ecklers, or the like...the only real horsepower costs $$...save and throw it into the heads (great place to get power) and the engine....
Team Owner
Joined: Feb 2006
Posts: 24,460
Likes: 7
From: sw Ohio
Last month I purchased an 87 Roadster with 50K on it. Auto.
This past weekend I added the following.
1.SLP Performance Cold Air Intake
2. Throttle Body Flow Booster
3. Power Coupler
4. DynoMax High Performance Mufflers with Y- Pipe.
All the above from Mid America. Says I gained over 45HP.
Car does run alot better, more responsive and gets better gas mileage.
Feels like maybe a 20hp gain at most.
My next phase is Air pump replacement pulley kit and headers.
Is the next phase worth the bang for the buck.
Love driving the C4 it is sooooo much better than my C3
This past weekend I added the following.
1.SLP Performance Cold Air Intake
2. Throttle Body Flow Booster
3. Power Coupler
4. DynoMax High Performance Mufflers with Y- Pipe.
All the above from Mid America. Says I gained over 45HP.
Car does run alot better, more responsive and gets better gas mileage.
Feels like maybe a 20hp gain at most.
My next phase is Air pump replacement pulley kit and headers.
Is the next phase worth the bang for the buck.
Love driving the C4 it is sooooo much better than my C3
2. no gain
3. no gain
4. possibly 15 hp
Headers will net you about 20-30 horsepower but they're a pain to put in depending on which ones you get. Deleting the air pump wont gain you anything but a cleaner engine bay.
Le Mans Master
Joined: Jun 2006
Posts: 5,642
Likes: 5
From: One day you're a Comet...the next day you're dust... Arkansas
Last month I purchased an 87 Roadster with 50K on it. Auto.
This past weekend I added the following.
1.SLP Performance Cold Air Intake
2. Throttle Body Flow Booster
3. Power Coupler
4. DynoMax High Performance Mufflers with Y- Pipe.
All the above from Mid America. Says I gained over 45HP.
Car does run alot better, more responsive and gets better gas mileage.
Feels like maybe a 20hp gain at most.
My next phase is Air pump replacement pulley kit and headers.
Is the next phase worth the bang for the buck.
Love driving the C4 it is sooooo much better than my C3
This past weekend I added the following.
1.SLP Performance Cold Air Intake
2. Throttle Body Flow Booster
3. Power Coupler
4. DynoMax High Performance Mufflers with Y- Pipe.
All the above from Mid America. Says I gained over 45HP.
Car does run alot better, more responsive and gets better gas mileage.
Feels like maybe a 20hp gain at most.
My next phase is Air pump replacement pulley kit and headers.
Is the next phase worth the bang for the buck.
Love driving the C4 it is sooooo much better than my C3
Race Director
Joined: Jun 2004
Posts: 13,963
Likes: 709
From: WI
Sorry you wasted some cash on that stuff. The power coupler will not help at all though if you show your car it is easier to clean then the rippled hose. The air foil in the throttle body doesn't help either, send it back if you can.
Team Owner
Joined: Sep 2001
Posts: 62,160
Likes: 1,733
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
You wasted plenty of money on that stuff, particularly 2-3.
The AIR replacement does not free up power, it is a cosmetic mod. The pulley on it rotates pretty freely already. Headers will wake the engine up though.
Toss the MidAmerica catalogs though.
The AIR replacement does not free up power, it is a cosmetic mod. The pulley on it rotates pretty freely already. Headers will wake the engine up though.
Toss the MidAmerica catalogs though.
Burning Brakes
Joined: Aug 2007
Posts: 792
Likes: 16
From: Austin Tx
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Le Mans Master
Joined: Apr 2005
Posts: 6,413
Likes: 9
From: The Old Dominion
I put that SLP cold air ram thing on my '87 back in the day. The car felt different with it when I'd put it in or take it out. 
It also tended to raise my coolant temps as it blocks off a fair bit of the radiator.
It also tended to raise my coolant temps as it blocks off a fair bit of the radiator.
Thread Starter
Melting Slicks
Joined: Oct 2005
Posts: 2,526
Likes: 99
From: Apache Junction, Arizona
St. Jude Donor '12-'13-'14-'15-'16
Thank You
I will put the Hedders on over the winter. Next step for now is to upgrade the radio. Putting in a Jensen 7" touch screen DVD slide out unit with new speakers.
This car is a great road car. My wife enjoys taking trips in it. She would never go more than a few miles in my 79.
