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HP Performance fox kit modifications/rebuild

15K views 112 replies 40 participants last post by  raceoholic330 
#1 ·
I made this thread to share my 'journey' in regards to the modifications I made to my HP performance kit to allow it to fit my 88 GT exactly the way I wanted it to. This is in no way a 'bash HP Performance' thread. I bought the kit used and in rough shape knowing that I would have to modify it to fit my needs. This is one of the original HP kits that was designed to work with a 60mm turbo. I originally only expected to have to make minor modifications, but as soon as I put the engine in the car, I quickly realized that major changes were necessary.



The passenger side fit fine. A little close to the boxed in frame rail, so that will be trimmed.


The driver side is where the issues were. There was no way in hell that the header was going to clear the beefy MM k-member.








My solution was to chop up the header and modify it so it would go between the power steering pump and frame rail.








I reused the original collector.


Good clearance to sway bar mount and frame rail.


Modifying that header left me with this:


So I re-built the crossover to mate up with the new collector. I also added a flex bellow while I was at it.






For those that are wondering, my turbo is choice was a Comp 76mm .96a/r with the billet wheel and ball bearing option. Oil fed and water cooled. Whole turbo weighs around 18lbs.






Next up is getting the turbo placement in the engine bay...
 
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#30 ·
Looks great! I really like what you did with the passenger side frame rail and apron. I am in the same boat with needing to mod the frame rail and build the apron back (it was ALL cut out previously).
 
#34 ·
Thanks. The car is really just going to be a ridiculously over-powered street/show car. It has an IRS out back, so it will be fun in the corners.

The engine is a 9.3:1 Dart 331 with AFR 185's and a custom FTI billet cam. The turbo is a 76mm ceramic ball bearing unit with a billet wheel. Water cooled. People seem to make really good power with the Comp turbos. Should be a fun ride when it's done!
 
#36 · (Edited)
800 is my magic number that I'm looking for. I have a meth injection system that I may put on at some point down the road, but I'm going to leave it off for the time being.

I used a PMS with my supercharged setup with great success, and I'll keep that for the turbo setup as well. I know my way around it and can get the car up and running. There is a shop to too far from me that can dyno tune the car with the PMS. Trans will be an MMR PT750 (TKO 500) with a spec stage 3 clutch, which was also from my supercharged setup. I think a twin disc setup will be necessary down the road though. I didn't mind the spec clutch at all, compared to some that don't like the stage 3. It will have 3.27 gears in the back. 275's are the biggest tires I can fit due to the IRS, so I'll probably go with something like the newer tread BFG drag radials. I'd like to get at least a little bit of the power to the ground!
 
#37 ·
i'm going to pm you in a lil bit,don't want to be messing your thread up..but if its cool,would like to pick your brain on the pms,i have one,never used it..its the series 4..this is in a 1995,so computer is a lil more tricky from what i gather.. i have a spec as well,but no disc..was thinking about a twin also..what would be your pick if you went with a twin setup?
 
#40 ·
I haven't updated this is a bit. Here are some more progress pictures.























I just made the last-minute change to use a Holley EFI standalone on the car. I was talking with my tuner, and my setup is going to be a little too wild for the PMS. The 95lb injectors aren't going to play nice with the MAF and PMS, so going standalone will help my idle and drivability, which is very important to me. More to follow as I get that installed.
 
#43 ·
Thanks 97stanger

I just used a 4" angle grinder to cut everything up. Everything is MIG welded. The insides of the frame rails were sprayed with paint using a 360 degree nozzle to coat everything inside and prevent it from rusting.

I'm excited to see how the Comp behaves. I did start the engine a few weeks ago and I loved how the turbo kept spinning a good 30 seconds after I shut the engine off.
 
#45 · (Edited)
Which of the Holley systems are you going with? HP or the Dominator?

Now you can drop the TFI big cap dizzy and even move to a coil-n-plug system. I assume you will be ditching the MAF and going speed density.
 
#46 ·
Going with the HP. I don't need all the inputs and outputs of the Dominator right now. I am ditching the TFI and going with a crank trigger and can sync distributor. No CNP setup right now, just for money and simplicity sake. Maybe down the road I'll make the switch. And yes, the MAF sensor is gone.
 
#49 ·
Thanks guys.

I got the car to the dyno saturday. Here's a video of the last pull we made for the day. My Fuelab pump decided to internall short itself, so we couldn't continue.

http://youtu.be/hbIKbzHFqxQ

665hp @ 5900, 633ft-lbs @ 5200 at 14 lbs of boost. The cam should make power to around 6800 and I'd like to get the max pressure to the 18-20psi range. The only other issue I had was smoking on decel. I washed the cylinder walls down with fuel when i first started the engine with the PMS, so that may be an issue. The car did quite well for it's first time out. After fixing a couple of things and sending the pump out for repairs, I'll give it another go to see what she can really do.
 
#50 ·
Absolutely beautiful setup! I used to run a 76mm turbo setup and went back to a YSI for the classic blown 5.0 sound. After watching that video and reading this post I have considered straightening out the twin 60mm turbo kit sitting on the shelf in my garage! It's a Cartech outlaw kit with twin60 on center turbos. It needs massive amounts fabrication to make it right but after reading this thread you give me the hopes of taking on that challenge! If I can now convince the wife and two kids to give me some free time!
 
#55 ·
Thanks guys



I did install the Holley. Aside from the fact that I had to splice a number of wires because I installed the ECU in the rear seat area, it was very easy to install. Anyone that installs the ECU where the stock one was probably won't have to splice anything. It will literally be plug and play. I know guys that wired it up in under an hour.

I tinkered with it a bit before I brought it to the tuner, and the user interface couldn't be any easier to navigate. I like it a lot. Top notch system.
 
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