After toying with a couple ideas I think I've finally settled on a f40 transmission and a LS4. Now I am looking for a turbo kit. I don't mind if I lose the trunk storage. does anyone know a kit that isn't too expensive?

There is not a kit to turbo an LS4 in a Fiero.

Not sure what your budget its, but LS4/F40/Turbo is 15K+ with you doing all the work. $25K+ if you pay someone else to do it.

[This message has been edited by fieroguru (edited 11-26-2024).]

Engine swaps certainly wake up the performance of the Fiero but horsepower costs money. Fieroguru has done the LS4 swap and I haven't but after doing six other assorted engine swaps they all cost a few thousand $$$ or more. With any swap you've got to fabricate (or buy) axles, mounts, wiring harness, fuel pump, .PCM (and programming) , A/C lines, exhaust system, belt tensioner, ignition wires, hoses/lines, cooling system, sometimes a new alternator, trans linkage mod etc etc etc. Then replace the bearing hubs suspension bushing and parts. All this is without a turbo and assuming that you don't need to rebuild the engine ( or modify it) that you plan to swap. Before you move forward I would suggest that you set a goal on what you want from your Fiero; street, street strip, road, show car or just a fun driver. Then decide your budget, gather up costs for the parts, quotes from a custom shop. There are really no inexpensive swaps.

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" 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 "

fieroguru, I spy that tubular cradle. Looks good.

And to build on what FieroGuru and Dennis said, if you go with a natural aspirated swap, the LS4 can get north of 400 HP with the right cam, decent heads and intake. It can get even further, but your cost-to-horsepower ratio gets worse.

Plenty of folks will also point out the idea that the 3800 supercharged can be swapped in 'cheaply'... but it looks it. Doing it without pipe fittings from home depot or hacked together wiring looms, it can get more expensive. The guy doing the hard work on my Ls4 swap did a 3800 supercharged swap on his Fiero, and he said if he knew now what he knew then, he would have done the LS4 swap.

Having done a few swaps; if I had to do a swap today I would probably not do a 3800SC. Its a great engine swap capable of high power , it fits and looks good, not hard to do. It just represents older 95-06 technology and whatever you locate today will most likely need rebuilding. The LS4 takes you to 2009 and 303 HP stock. The chance of finding one in "bolt in" shape is probably better but the naturally aspirated V8 engine looks like it is just about obsolete.
More recently the GM LFX and now the DOHC LFG high feature DI V6 engines provides better technology and a broader torque curve. That would be my engine swap choice today. They are light engines, present a more difficult swap but in some versions can get you over 300HP stock
Choosing a Fiero swap can be a difficult decision, so I would do a lot of research before moving forward.

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" 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 "