New question, old info (Page 2/2)
Trinten JUN 09, 12:18 AM
There's a book out there you can still get High Horsepower Fieros. It's not encyclopedic, but it's a great primer and gives some solid ideas on what has been done.

As others have said, trying to push a lot of power through any of the OEM engines is going to have challenges. A fellow Fiero owner was recently doing a rebuild on an engine and lamented the difficulty in finding new pushrods (I think it was for their Iron Duke). It might be worth saving any OEM engine you have, especially for parting out as parts become more rare, and consider an inexpensive swap.

Now to talk out of both sides of my mouth, I also have no issues with someone who says "this is what I want, and it's what I'm going to do". I won't roast you for going that direction, many of us here just want to make sure people have as much information to make a sound decision first. (and yes, some people will roast you. It is the internet, afterall).

Welcome!
1of269 JUN 14, 02:07 PM

quote
Originally posted by IMSA GT:

What is your goal with the setup? Do you simply want a few extra horsepower or do you want to do a full build-up on the motor?



I'm tearing the motor down and doing a full rebuild. I've been building Turbo motors since the 80s, but always used forged internals. Of course a forged 2.8 crank has to be custom made so that's why I asked if anyone knows how much boots a factory one can handle, then I thought, maybe rods too, but for this build I'll end up using SBC rods.
1of269 JUN 14, 02:09 PM

quote
Originally posted by Trinten:

There's a book out there you can still get High Horsepower Fieros. It's not encyclopedic, but it's a great primer and gives some solid ideas on what has been done.

As others have said, trying to push a lot of power through any of the OEM engines is going to have challenges. A fellow Fiero owner was recently doing a rebuild on an engine and lamented the difficulty in finding new pushrods (I think it was for their Iron Duke). It might be worth saving any OEM engine you have, especially for parting out as parts become more rare, and consider an inexpensive swap.

Now to talk out of both sides of my mouth, I also have no issues with someone who says "this is what I want, and it's what I'm going to do". I won't roast you for going that direction, many of us here just want to make sure people have as much information to make a sound decision first. (and yes, some people will roast you. It is the internet, afterall).

Welcome!



Thank you! I'll go look for a copy of the book.
Dennis LaGrua JUN 14, 11:03 PM

quote
Originally posted by 1of269:


I'm tearing the motor down and doing a full rebuild. I've been building Turbo motors since the 80s, but always used forged internals. Of course a forged 2.8 crank has to be custom made so that's why I asked if anyone knows how much boots a factory one can handle, then I thought, maybe rods too, but for this build I'll end up using SBC rods.



If you are talking about adding a billet custom forged Moldex crankshaft, it will cost big bucks. The stock 2.8L crankshaft was made for a 140 HP engine. If you turbo with high boost, this could put the engine in the 200+ HP range. The stock crankshaft may hold up but then again it might not.

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"THE COLUSSUS"
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pmbrunelle JUN 15, 06:51 PM

quote
Originally posted by 1of269:
I asked if anyone knows how much boots a factory one can handle, then I thought, maybe rods too, but for this build I'll end up using SBC rods.



Stock rods, stock crank:
https://www.fiero.nl/forum/...090907-1-066752.html

The 3.4 DOHC has the same factory forged connecting rod as the 2.8 Fiero... but four valves per cylinder.

What is your plan for getting the engine to breath enough to stress the bottom end?
ericjon262 JUN 16, 09:46 PM
while forged parts are great, I think it's more important to have a proper ring gap, good bearing clearances, and excellent engine management. the forged bits will make the engine a bit "safer", but even the most robust build will fail if it isn't properly tuned, or the ECU can't properly manage AFR and spark.

air to water intercoolers are going to be the way to go on a Fiero IMO. Some guys have run air to air with success, but I'm not wild about them. they will have more charge piping, which leads to more boost lag, and there isn't a ton of airflow in the back of a Fiero.

PMBrunelle has a wicked water/meth setup, which is probably lighter than a A2W, but you have to fill it, and have some way of maintaining safe operation in the event of running out, it's been a while since I looked over his whole thread, but I believe he has a low level sensor, and pressure transducers to monitor system operation.

As much as I despise seeing a late model block with Fiero heads and intakes, if stock+turbo is more of a looks thing, and you're going to build an engine anyways, pick up a 3400 block, they have a stronger bottom end, priority main oiling, a roller cam (with aftermarket cams available) provisions for crank and cam position sensors (supports SFI with the right ECU) and is almost a bolt in for the stock 2.8 block. the later model aluminum heads are leaps and bounds ahead of the fiero heads for numerous reasons. and the base engine is probably a better candidate for boost.

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"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."

cognita semper

[This message has been edited by ericjon262 (edited 06-16-2022).]