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Is a quad 4 worth it?
04-23-2008, 12:31 AM
I have a 1987 fiero 2M4. My old iron duke needs some work and i want some more power. I dont want to put a 3800 in it because it will add unwanted weight. So im lookeing for other solutions, a quad 4 seems like a likely choice. Im just looking for input on helping me make my decision. Thanks for your help!
04-23-2008, 11:12 AM
Finding a good quad four may be a problem. They were a good option ten years ago. You are right that coaxing more power from the 2.5 duke is a challenge. It all depends on how much you want to spend as to what engine and how much power you want. From what others have told me the 87 Fiero coupe with it's four was one of the better of the four cylinder Fieros made, but still less than 100 hp. If you find a Quad 4, it would undoubtable need a rebuild. Almost any newer four cylinder engines require new computer systems ie the 2.2/2.4 Ecotech engines from a Cobalt.
Gerry Goodwin from Kokomo IN, did a beatiful conversion with a Quad 4, years ago, however he was a very talented machinist and the engine looked like it belonged in the Fiero. The car was sold off at the NIFE show last year as a door prize. Someone got a good deal on that car.
04-23-2008, 10:12 PM
Haha no doubt someone is enjoying that car. Do you have any other suggestions for me?
04-24-2008, 12:59 PM
"coaxing more power from the 2.5 duke is a challenge"
Say what? The 2.5 has more race parts and high performance street parts available than most any other domestic 4-cylinder (possible exception, 2.3 Ford). Check the GM Performance catelog. Pontiac developed the 2.5 "Super Duty" for the Goody's Dash race series. We've managed 310 HP from a 2.7 lr. version with no power adders. The aluminum head is a work of art!
This doesn't mean I support the idea of pumping one up to that level, but be more aware of what's out there.
Another, more practical idea, is to use a 3.4 (iron heads) FWD 60 degree V6. 250-275 HP is no problem, and the small V6 weighs LESS than the 2.5. It's based on the same block as 2.8, which was a standard engine in Fiero. ALL the parts to bolt one in are readily available.
04-24-2008, 01:01 PM
cool thanks a lot man, that helps a lot!
04-26-2008, 12:43 AM
well you seem to kno what your talking about, what do you think of a getrag tranny. Or what do you suggest?
04-28-2008, 01:11 PM
Not sure what your choices are for the 4 cylinder. The Muncie and Opel (Getrag) transmissions were both fine behind the 6s. My research said they used what was more readily available at the time of production, rather than any special features. My '86 2M6 and '86 GT had the Getrag. My '88 GT has the Muncie. Never had a problem with the '86s. Had a carrier bearing go bad in the '88, but it had over 175K miles on it at the time.
We're piecing together an '86 for a "drag car", and opting for the 4-speed. It has more desirable gearing for a "strict" 1/4 mile car.
04-28-2008, 11:04 PM
Aight, are there a lot of performance options for the 6 cylinder. Cuz im into upgrading my engine.
04-29-2008, 12:35 PM
Money is the limit to what can be done to the 60 degree V6. It's light and very tough. Some combinations won't physically fit in the P-body without changes, so don't spend a bunch until you know what you need.
GM Performance offers an aluminum block for the 2.8/3.1. It's "bisexual" (FWD/RWD) so it will fit. Heads are reasonable, and can be made to flow quite well.
The biggest limitation is the intake "plenum", as some report RPMs drop off after about 7,500.
Lots of good parts out there, though.
04-29-2008, 05:02 PM
Cool. Is that V6 the same one that comes in the Grand Prix's and stuff?
04-30-2008, 01:07 PM
Yup. The very same. BUT... The aluminum heads on the GPs, etc. won't fit in the Fiero engine compartment, and the iron heads will have to be "subbed in". That calls for a piston change as well, to keep compression high enough to make any power.
If you know someone REALLY GOOD at fabrication, one could make an intake AND a water pump housing to make the aluminum heads "fit". Exhaust changes would be necesary, too. Snowball effect... But with the aluminum heads, due to their later design, MUCH more power is available. $$$$$
04-30-2008, 09:07 PM
Ahh i see. Well im pretty good at fabrication so maybe i ll give it a whirl. My bro has a grand prix with the 3100 and i like that engine a lot.
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