I plan on cramming a 800 horsepower engine into a fiero I know I will have to build a transmission to handle that I am just curious if anyone knows a good way to reinforce the body of the car itself to handle that kind of power I have heard people say it can get a little wiggly around the 350 mark
I plan on cramming a 800 horsepower engine into a fiero I know I will have to build a transmission to handle that I am just curious if anyone knows a good way to reinforce the body of the car itself to handle that kind of power I have heard people say it can get a little wiggly around the 350 mark
You'll want to define what it is that you want. 800 horsepower is a great number, but is it the number you're interested in, or the performance you're interested in?
Remember that the Fiero w/ a fully loaded V6 is a 2,800 pound car. In 1995-1996, the C4 Corvette weighed about 3,400 pounds and put out 330 horsepower. What I mean is, if you want a LOT of performance, you don't need 800 horsepower... you probably only need like max 500. It has less to do with the frame, and more to do with the fact that it's a really light car and it can be difficult to get the power to the ground.
Being a mid-engined car, it's designed more for handling. But, it's rear wheel drive so when you accelerate hard, the weight will shift to the back giving you better traction. Me personally, I think 800hp is shooting for too much, you won't be able to make use of that much HP. Even the Dodge Hellcat or Wildcat has a difficult time making use of that kind of horsepower, even with traction control (which effectively limits that horsepower until it can maintain traction).
This topic is a pipe dream that will never come to fruition. ..
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
Come on, don't be mean guys... we've all been there. None of us were born with all the wisdom of what should be. It's exciting to think about the possibilities. We don't want to be negative... we want to support and help him refine his goals to something that's realistic and results in a happy experience.
82-T/A: Come on, don't be mean guys... we've all been there. None of us were born with all the wisdom of what should be. It's exciting to think about the possibilities. We don't want to be negative...
I bet many members put posters on their bedroom walls as a kid, with stunning hyper-cars and jaw-dropping bikini-cladded supermodels with matching high heels....
However, when moving from childhood into an adult, these fantasies {which were way out of reach} fade; and reality sets in with a more sober, realistic perspective.
Perhaps, Josh86gt is still more in the former, than the latter...
[This message has been edited by Vintage-Nut (edited 02-20-2025).]
Getting the chassis to handle 800 hp is not super difficult as its already fairly stiff. I'd be more worried about finding a fwd transmission that can even handle that power. Before I started my K swap, I wanted to do an LS4 swap but I could never find a transmission that could handle the stock 300 hp, let alone 800. The chassis for the Fiero can handle the power fine. its the transmission thats the issue.
Getting the chassis to handle 800 hp is not super difficult as its already fairly stiff. I'd be more worried about finding a fwd transmission that can even handle that power. Before I started my K swap, I wanted to do an LS4 swap but I could never find a transmission that could handle the stock 300 hp, let alone 800. The chassis for the Fiero can handle the power fine. its the transmission thats the issue.
That's true. If you're going to do 800hp, you'd probably end up having to go with a TH-425 / Eldorado & Toronado transmission... mount it longitudinally in the rear, and elongate the engine compartment, or go with a twin-turbo V6 and cut into the trunk.
I have 407HP at the wheels (457 on a good day!) and that's a hell of a lot for such a small old car. You have to be running a really expensive Porsche, BMW or supercar to catch me on track. (Better chassis, better brakes, better tyres, etc...) I toast most cars of the same era, even modified ones like mine.
800HP is overkill and totally uncontrollable in my opinion on a basically stock Fiero frame with it's antique suspension. You'll kill yourself...
And by the way, it's the torque and the adherance that you need for fast acceleration, not too much power.
------------------ "Turbo Slug" - '87 Fiero GT. 3800 turbo. - The fastest Fiero in France! @turboslugfiero https://youtu.be/hUzOAeyWLfM
You would be amazed at what you can get used to...
6 years and 55K miles with my LS4/F40 with 382 rwhp or between 425 to 450 fwhp. It was a blast, but I got used to it and wanted more.
Now with the upgrades and turbo, I am approaching 700 fwhp and have about 6,200 miles on it. 1st and 2nd gear is wheel spin city if I want it, 3rd is a rocket (4th would be north of 125 mph).
The car is currently getting an ecm upgrade so I can have boost by gear and traction control. Both will help detune 1st and 2nd gear so I can better match the power with the traction. Also adding an intercooler and will likely switch to e85 and start bumping the boost more in 3rd and 4th.
I got a ride in JCMUTT, I think that's his name here; 600+whp 3800 turbo and what I experience!! The adrenalin didn;'t let me sleep that night! Incredible acceleration!
I plan on cramming a 800 horsepower engine into a fiero I know I will have to build a transmission to handle that I am just curious if anyone knows a good way to reinforce the body of the car itself to handle that kind of power I have heard people say it can get a little wiggly around the 350 mark
Not sure why people are reporting chassis "wiggle" above 350 hp.
The good thing about a rear mid-engine car is that, unlike a front engine rear wheel drive car, torque does not need to be transmitted from the front to the rear. The front engine / rear wheel drive configuration requires stiffer and stiffer chassis as engine torque increases. With a rear-mid car, simplistically, all you have to worry about is the engine ripping itself off of the engine mounts.
You would be amazed at what you can get used to...
6 years and 55K miles with my LS4/F40 with 382 rwhp or between 425 to 450 fwhp. It was a blast, but I got used to it and wanted more.
Now with the upgrades and turbo, I am approaching 700 fwhp and have about 6,200 miles on it. 1st and 2nd gear is wheel spin city if I want it, 3rd is a rocket (4th would be north of 125 mph).
The car is currently getting an ecm upgrade so I can have boost by gear and traction control. Both will help detune 1st and 2nd gear so I can better match the power with the traction. Also adding an intercooler and will likely switch to e85 and start bumping the boost more in 3rd and 4th.
Longterm goal is AWD...
Sounds sweet what are you doing about the transmission I'm still trying to figure something out?
You would be amazed at what you can get used to...
6 years and 55K miles with my LS4/F40 with 382 rwhp or between 425 to 450 fwhp. It was a blast, but I got used to it and wanted more.
Now with the upgrades and turbo, I am approaching 700 fwhp and have about 6,200 miles on it. 1st and 2nd gear is wheel spin city if I want it, 3rd is a rocket (4th would be north of 125 mph).
The car is currently getting an ecm upgrade so I can have boost by gear and traction control. Both will help detune 1st and 2nd gear so I can better match the power with the traction. Also adding an intercooler and will likely switch to e85 and start bumping the boost more in 3rd and 4th.
Longterm goal is AWD...
i figured put everything awd for the pre 88 minus a bolt in system from a gm that isnt mcpherson. ive been debating on s10 4wd stuff since it should fit
Originally posted by Brian A: Not sure why people are reporting chassis "wiggle" above 350 hp.
The good thing about a rear mid-engine car is that, unlike a front engine rear wheel drive car, torque does not need to be transmitted from the front to the rear. The front engine / rear wheel drive configuration requires stiffer and stiffer chassis as engine torque increases. With a rear-mid car, simplistically, all you have to worry about is the engine ripping itself off of the engine mounts.
I think it has more to do with rear toe changes with higher hp/tq engines due to bushing deflection (and why I run rod end lateral links). Could also be chassis rust in the rear frame rails. If you are going to build a high hp/tq Fiero, start with a rust free chassis.
Fiero drivetrains do load the chassis, but differently. The front engine/rear wheel drive chassis sees a rotational force from front to rear due to engine torque x transmission gear ratio. The Fiero chassis sees a bending moment between the rear frame/cradle and the passenger cabin equal to engine torque x transmission gear ratio x final drive. In 1st gear, if there is no wheel spin, this can be in the 4,000 to 5,000 ft-lb range.
This is why engine/transmission mount design on high torque fieros is so important and why Tripots, axles and CVs are prone to break.
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Originally posted by Josh86gt: Sounds sweet what are you doing about the transmission I'm still trying to figure something out?
Sticking with the F40.
While the F40 is the most expensive manual transmission for a Fiero swap, it is the only one with final drives better suited for high hp/tq applications. My car has the 3.091 final drive swapped in which means 7000 rpm in 1st, 2nd, 3rd and 4th are 44 mph, 82 mph, 126 mph and 176 mph. So it has really long legs which makes the car feel like a late model car with a V8 vs. and over geared hot rod. This also means it pulls down 29 mpg (when it was naturally aspirated) and 27 mpg with the current turbo setup, with a goal of hitting 30 mpg.
It has room for a 9 1/4" twin disk clutch. With organic clutch discs, it has near stock engagement, with a 800 hp rating. Semi-metallic clutch disc material is available to bump the rating over 1000 hp). I swapped out lathes so I had one big enough so I could design and machine the needed flywheel to use this clutch.
It is also the only one with a factory AWD version with 320 hp in a car that weighs over 3500 lbs, with a zero to 60 of 5.6 sec. GM never trusted the F23 to do this under a factory warranty so that speaks volumes in my book. I purchased a CNC mill so I can design and machine the custom center housing for the AWD unit that will allow flipping the output of the AWD unit to the front of the car, and run through a modified oil pan.
You should take some time and review some build threads in the construction zone. Start with the ones that are 15+ pages long and start from the back so you can see where they got to. Once you find and interesting one, start at the beginning and read the whole thing.
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Originally posted by cartercarbaficionado: i figured put everything awd for the pre 88 minus a bolt in system from a gm that isnt mcpherson. ive been debating on s10 4wd stuff since it should fit
My car is an 88, so the CNC mill was also purchased so I could design and machine new aluminum uprights front and rear to address the wheel bearing/CV reliability issue. The front will get a SAAB factory AWD rear diff installed (flipped over) in the front with a custom tubular cradle and aluminum suspension arms. This will allow the car to be AWD at its current stance.
This year is about optimizing the turbo/ecm/boost/traction control. Next winter will be likely get back to the uprights and move on to the front suspension.
[This message has been edited by fieroguru (edited 02-22-2025).]
My car is an 88, so the CNC mill was also purchased so I could design and machine new aluminum uprights front and rear to address the wheel bearing/CV reliability issue. The front will get a SAAB factory AWD rear installed (flipped over) with a custom tubular cradle and aluminum suspension arms. This will allow the car to be AWD at its current stance.
This year is about optimizing the turbo/ecm/boost/traction control. Next winter will be likely get back to the uprights and move on to the front suspension.
Sounds like a crazy task can't wait to see the finished product I'm sure it will be amazing
My car is an 88, so the CNC mill was also purchased so I could design and machine new aluminum uprights front and rear to address the wheel bearing/CV reliability issue. The front will get a SAAB factory AWD rear diff installed (flipped over) in the front with a custom tubular cradle and aluminum suspension arms. This will allow the car to be AWD at its current stance.
This year is about optimizing the turbo/ecm/boost/traction control. Next winter will be likely get back to the uprights and move on to the front suspension.
Quick question what year was the f40 that you got the 3.09 fd from?
I was curious if anyone knows a good radiator for the 600-800 hp range?
You would want to build the motor first, to define what kind of radiator would go in it. The stock Fiero cooling system is pretty decent as it has more cooling capacity than most modern cars (because of the tubes running under the drivers side and passenger side, which hold coolant too). But I'd imagine you'd want a 6-core radiator for something like 800hp.
Originally posted by Josh86gt: Sounds like a crazy task
It is... but I like to do interesting/challenging things to continue to expand my skills and keep my car unique.
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Originally posted by olejoedad: guru, you never cease to amaze!
Kudos to you!
Thanks! You & Jack planning to do the HRPT this year? Day 1 - Mon, June 9 – Lucas Oil Indianapolis Raceway Park, Indianapolis, IN Day 2 - Tues, June 10 - Route 66 Raceway, Joliet, IL Day 3 - Wed, June 11 - Allen County War Memorial Coliseum, Fort Wayne, IN Day 4 - Thu, June 12 - Monroe County Fairgrounds, Monroe, MI Day 5 - Fri, June 13 - Summit Motorsports Park, Norwalk, OH
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Originally posted by Josh86gt: Quick question what year was the f40 that you got the 3.09 fd from?
2008-2013 Vauxhall Insignias with the A20DTH diesel engine. The 3.091 was an optional gear ratio and hard to verify prior to purchase. They are not available in the US or Canada, so you have to purchase a transmission from the UK and have it imported. Then tear it down for 3 pieces. I did a build thread on it in 2017: https://www.fiero.nl/forum/Forum1/HTML/097738.html
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Originally posted by Josh86gt: I was curious if anyone knows a good radiator for the 600-800 hp range?
Champion 3 core with the stock Fiero fan is what I run, and so far it works well. This is also what 90% of the stock chassis high hp Fieros run. The longest time you will actually be WOT producing 600 to 800 hp will be under 1 minute if you take it to a standing mile event.
Engine bay heat management and aero are far more more critical than engine coolant temp management.
Champion 3 core with the stock Fiero fan is what I run, and so far it works well. This is also what 90% of the stock chassis high hp Fieros run. The longest time you will actually be WOT producing 600 to 800 hp will be under 1 minute if you take it to a standing mile event.
Engine bay heat management and aero are far more more critical than engine coolant temp management.
Thanks a lot you have helped me learn a lot about these little cars
I was curious if anyone knows a good radiator for the 600-800 hp range?
Like Guru mentioned, the Champion works for him. But what really matters is the frequency or how long that radiator will be cooling an engine making 800hp. Is it for a couple of burst of 800hp? Is it for 30 laps around a short track with lots of turns that don't allow the radiator to get enough air flowing throw it while you are demanding 800hp constantly? Or is it around a track with long straights where you are demanding 800hp for longer periods of time? Do you only drive your car hard in the winter or in the Summer? In my case I'm making 386whp, but because I don't have a turbo and two less cylinders than Guru I can afford to use a smaller radiator but it has to be big enough to dissipate the heat for the amount of power and the conditions I use my Fiero which is why I use a radiator that is rated for a 600hp car. More cylinders and turbo charging makes more heat so you have to plan and calculate your heat dissipating apparatus accordingly.
Like Guru mentioned, the Champion works for him. But what really matters is the frequency or how long that radiator will be cooling an engine making 800hp. Is it for a couple of burst of 800hp? Is it for 30 laps around a short track with lots of turns that don't allow the radiator to get enough air flowing throw it while you are demanding 800hp constantly? Or is it around a track with long straights where you are demanding 800hp for longer periods of time? Do you only drive your car hard in the winter or in the Summer? In my case I'm making 386whp, but because I don't have a turbo and two less cylinders than Guru I can afford to use a smaller radiator but it has to be big enough to dissipate the heat for the amount of power and the conditions I use my Fiero which is why I use a radiator that is rated for a 600hp car. More cylinders and turbo charging makes more heat so you have to plan and calculate your heat dissipating apparatus accordingly.
What kind of radiator do you have in your car I would just like something a little closer to what I will be making max for comfort reasons
What kind of radiator do you have in your car I would just like something a little closer to what I will be making max for comfort reasons
Here is my current radiator. Its a Summit Racing unit for a Fbody 600hp Camaro. I had to do some grinding to fit it in. Unlike Guru I don't care about the Concours D' Elegance finishing, I'm all bout practicality. Now this one is for the big block V6 NA project I'm finishing. By the size you can conclude more power (heat) is expected.
Here is my current radiator. Its a Summit Racing unit for a Fbody 600hp Camaro. I had to do some grinding to fit it in. Unlike Guru I don't care about the Concours D' Elegance finishing, I'm all bout practicality. Now this one is for the big block V6 NA project I'm finishing. By the size you can conclude more power (heat) is expected.
I was thinking about this a bit and would it be possible to have the f40 internals and case made from billet 4340 aluminum or would it not add enough strength to do anything meaningful?
...Engine bay heat management and aero are far more more critical than engine coolant temp management.
Yes, this is true. I've had to make heat shields to stop critical sensors from getting too much radiant heat (transfer of heat through electromagnetic waves). As for the aero, Fieros just "white knuckle" drive above 200km/h! Ha, Ha!
------------------ "Turbo Slug" - '87 Fiero GT. 3800 turbo. - The fastest Fiero in France! @turboslugfiero https://youtu.be/hUzOAeyWLfM
I was thinking about this a bit and would it be possible to have the f40 internals and case made from billet 4340 aluminum or would it not add enough strength to do anything meaningful?
I think it would be worthwhile to cryo treat the case and internals as Ive heard that can improve the amount of power the parts can take by quite a bit. I'm not aware of any billet F40 internals being available to purchase unless you got a machine shop to whip up a set for you.
I think it would be worthwhile to cryo treat the case and internals as Ive heard that can improve the amount of power the parts can take by quite a bit. I'm not aware of any billet F40 internals being available to purchase unless you got a machine shop to whip up a set for you.
That's what a was planning is to send my parts in and have them copied in 4340 aluminum I hear the stock gears are cast but I was getting mixed info on that
Maybe it was an autocorrect issue but 4340 is a steel alloy and not aluminum.
If you wanted to have all the internals remade of the strongest materials and have a billet aluminum case, plan for $100k cost of entry.
It would be far cheaper to get a custom Quaife transaxle and use an adapter plate.
My bad I'm not very knowledgeable with different metal alloys but would you happen to know what type of aluminum the f40 uses so that I can find something roughly 1.5 times as strong?
