This post has been a long time coming. If you have been in the Southeast Michigan area or went to the Fiero 40th you have probably seen this car, but this is the first time I have posted about it.

I bought Jims88’s LS4 swapped 88 Formula Fiero in Fall 2019. He deserves all the credit for shoving the LS4 neatly into this chassis and his detailed build thread convinced me to buy his project. I have had many people comment that it looks stock and they were impressed by how clean it looks. His great build thread is here: https://www.fiero.nl/forum/Forum2/HTML/125877.html

Since then I have made a lot of modifications to it, and have more to go. My goal is to have a car that I can cruise around town in as well as take to the occasional road course track or HPDE event. I’ll keep this post short and add links to it as I post more details. Enough talk, here are pictures.








Modifications:

• 5.3L LS Truck manifold and throttle body, 4in intake, LS7 MAF, DoD delete, complete engine rebuild with upgraded valvetrain to raise redline to 6800 rpm
  
• Triple Edge performance rebuild of 4T65e-HD transmission to 385ft-lbs torque limit
  
• ‘87 GT Aero body swap (replaced all rivets with bolted rivnut connections)
  
• Louver Hatchback with supports (I will rework this now that I have access to a shop)
  
• Cantilevered 71” wide rear wing from 9 Lives Racing
  
• Showcars fiberglass Aero splitter with custom cutout for front end
  
• Fully ducted and vented cooling airflow with louvered hood vent
  
• Embrace Racing Bi-Xenon Headlamp kit with quality of life modifications
  
• Wilwood 4-piston brake calipers with Fiero Guru’s ‘88 13in rotors
  
• Steven Snyder's adjustable upper controls for ‘88s
  
• Rodney Dickman rebuildable ‘88 front bearings
  
• LS4 King’s Baffled Oil Pan
  
• Aux Transmission Cooler
  
• Quick disconnect steering wheel
  
• Digital Dashboard
  
• A couple quality of life changes: Throttle by wire pedal, relocated ECUs to stock Fiero location, added bigger mufflers

A quick timeline since late summer 2019:
I had the car less than a month or two when I took the car to Waterford Hills raceway for a shakedown track day. The car did fine for the first session and even passed a couple novices in Porsches, but during the second session of the day I overheated and it shutdown on track. I limped the car home and found out I had overheated and spun a couple bearings. With the engine and trans out for rebuild I took the opportunity to get a lot of work done on the car. Covid set me back, but finally in the summer of 2021 I had the car driving again. Then over the last couple years I have been working through all the modifications. Most of my work has been in my shed with hand tools, materials from ACE, Home Depot and McMaster. The most “precise” tools being digital calipers, a miter saw, table top drill press, and table top belt sander. I’m not bragging, I’m making excuses for the quality of my work and the tradeoffs I made in designs. At the start of 2023 I finally got access to a small machine shop and I’m starting to use their lathe, mill, and welder.

I’m at a nice point to take a bit of a break on the car, because my next steps involve wider suspension, custom widebody, custom exhaust, and maybe a manual swap.

[This message has been edited by Wererabbit91 (edited 07-30-2023).]

Hey, it's Patrick from the 40th Anniversary barbecue parking here.

I'm on this forum pretty regularly, so if you post updates on your project here, I'll be reading!

That is looking good. Thanks for sharing your unique project!

Since you have access to that machine shop now, I'd love to see you incorporate a real working diffuser. You would need to cut out the bottom portion of the trunk for it to be effective. And of course install a tray under the engine.

quote Originally posted by pmbrunelle: Hey, it's Patrick from the 40th Anniversary barbecue parking here. I'm on this forum pretty regularly, so if you post updates on your project here, I'll be reading!

It was great meeting you at the 40th and thank you again for volunteering to help with the cookout parking! I plan to make separate threads for the more detailed posts and then add the links to this thread. I use "The Aero Fiero" in the post titles.

Are the rear mufflers supported correctly? That's a lot of weight back there. If you plan to keep the same setup for the exhaust, you can find smaller mufflers that tuck into the openings. Here is the Valvoline car. Notice the exhaust tip.

[This message has been edited by IMSA GT (edited 07-30-2023).]

The stock LS4 exhaust headers combine into a 2.5in downpipe on the back side of the engine. Then I have a Y section that splits it out to the sides where a 90 deg turns its rearwards I attach those mufflers you see. So the exhaust is supported at the downpipe and at the 90 deg turns. This is not the final exhaust I want on this car, so I just need this to last a couple years. Here is a picture of the mounts I have at the 90s. So far I have not had any issues with this mounting, though I will agree its not the best.

Looks good