Iron Duke Fiero 5spd any Fun?

Are the 2.5 liter 4 cylinder "Iron Duke" powered 5 speed Fieros any fun? There is an '85 close by that I may take a look at. Any thoughts?

Thanks,

Ray

Well, my century had a 2.5. They make 90 some HP at the crank and don't want to rev over 4500 rpm. The fiero version may be different, but that was easily the least entertaining engine ever. It was attached to a 3 spd auto which didn't help either.

My buick did get awesome gas mileage though. And they never, ever break.

I can't speak for the Fiero, but my 5spd 1.5l X1/9 is very fun.

Power:Weight ratio is probably similar.

as long as you dont like high reving engines you should be fine. i dont think anyone on this website likes high revvers right?

seriously though, if you rev the crap out of it, it will break.

just drop in an SBC and eat transmisions like there is no tomarrow. you might be able to get 1 good 1/4 mile pass or autoX lap before you need a new one

Iron duke Fieros are tons of fun....after you swap out the engine. Seriously, just about every GM engine under the sun has been dropped in there, the 2.5 will be fun for about 7 seconds before you are ready for an upgrade. Also, if you want to hang it out, the '88 rear suspension will make things MUCH more fun (rather than scary) to drive.

Bryce

Connecting rod failures killed most of those by now. I'd plan on an engine swap with pretty much anything else.

Yes, they are. I had a chance to autox one several years ago(nocones, where are you???). I was quite surprised by how fun it was.

The torque is plenty to pull you off the line, but it's no top-end screamer by any means. And of course it's a relatively low/wide/flat car so it handles better than pretty much every other GM offering other than the Vette(stock, anyway).

All in all, it's probably a bit slower than a 1.6 Miata stock vs. stock, but still has plenty of grin factor.

I remember reading just before the Fiero's debut, that some folks inside GM wanted to equip the Fiero with the 1.6 Chevette engine. The engineers inside GM that were battling to get this "radical" car built were trying to pass it off as a "commuter-mobile" so the folks at Chevy wouldn't feel threatened. The Iron Duke, besides seeing duty in X-cars, and FWD GM intermediates, was also the "economy engine" in the S trucks. How much fun do you think a truck engined "sporty car" might be? Also keep in mind that GM isn't in the same league as VW or Honda when it comes to shifting on their manual trannys.

The are fun with a a northstar in them.

2.5 is low on HP for the weight of the car. Either Swap the engine, or hold out for a 2.8 V6, and even then it is a little low on HP.

(had an 88 GT for a while)

It is true that they were promoted as a "commuter mobile." The 4 cyl with 5 speed is capable of 30 mpg if not driven in anger. It could be a fun run-about if the price is right.

I had one in High School. I thought it was painfully slow and I'd only driven a handful of other cars to compare it to. Hated to be revved. Sounded like absolute poo. I thought quite possibly the worst choice for a sporty car motor ever.
Mine never broke though, and I hear more people tell me the 2.5 was a reliable motor than otherwise.

Oh man. 4sp + 4500rpm redline = very low top speed. The noise behind your head made you not WANT to go over 65. BTW, mine was a absolutely perfect 70k mile example. Maybe it really was a good car for a high school kid now that I think about it.

geomiata wrote: seriously though, if you rev the crap out of it, it will be time for a Quad Four or Ecotech swap.

Fixed. :)

integraguy wrote: I remember reading just before the Fiero's debut, that some folks inside GM wanted to equip the Fiero with the 1.6 Chevette engine. The engineers inside GM that were battling to get this "radical" car built were trying to pass it off as a "commuter-mobile" so the folks at Chevy wouldn't feel threatened. The Iron Duke, besides seeing duty in X-cars, and FWD GM intermediates, was also the "economy engine" in the S trucks. How much fun do you think a truck engined "sporty car" might be? Also keep in mind that GM isn't in the same league as VW or Honda when it comes to shifting on their manual trannys.

A truck engine sounds like a good time, actually...something like a 5.3 V8 ought to do. ;) The '90 Fiero would have finally got a cool engine (the DOHC V6) but the program was killed so all it ever got was econo-engines. As far as shift quality, I'm not sure which Fiero gearbox you're basing your statement above from, but the Muncie 4 speed is the only one that people really gripe about. Keep in mind that GM doesn't make these manual transmissions. The 5 speed Isuzu (used with the 4 banger) and 5 speed Getrag (used with the V6) shift just as well as any Honda from the same era I've had (such as my EF Civic 5 speed). I will say that the factory GM shifter sucks because the throw is really long and it's positioned at an angle like F-body shifters were, swapping it out for a shorter throw unit (or cutting and rewelding) makes a huge difference. However, if you shorten the shifter and replace the worn 20+ year old bushings on the shift cables ( www.rodneydickman.com has cheap, easy, quality upgrades) they shift fantastic IMO.

jrw1621 wrote: It is true that they were promoted as a "commuter mobile." The 4 cyl with 5 speed is capable of 30 mpg if not driven in anger. It could be a fun run-about if the price is right.

Actually, they get about 35 mpg (highway) as a commuter mobile, they really are pretty fuel efficient. There are people who have got them to the 40ish MPG range with some careful attention for highway commuting, but I wouldn't use the duke somewhere with high speed limits (as others have mentioned above). They make a great commuter because they're quite comfortable. The super low seating position does take a bit of getting used to, but that's more a mental/habit thing than a comfort thing.

Bryce

I'd think a BIG V-8 would throw off the cars wieght distribution, i'd look into a 3.8 Supercharger swap. Parts are plentiful and can be had relatively cheap. Just my .02 Cents.

Actually, the modern aluminum V8s are the same weight as the ol' iron duke...and significantly lighter than the 3800 SC (which is a heavy mother, tons of iron plus that heavy supercharger on top of it all). The 3800 SC can make a ton of power and is a great engine for drag racing, but for handling it's about one of the heaviest engines you can pick.

Bryce

integraguy wrote: The Iron Duke, besides seeing duty in X-cars, and FWD GM intermediates, was also the "economy engine" in the S trucks. How much fun do you think a truck engined "sporty car" might be?

I don't know, it seemed to work for the British.... most of their cars seemed to be powered by some derivative of a tractor motor, at least until the Lotus Twin Cam came along.

Too bad GM never thought to make the Quad 4 an option. I will never understand how that company can purposely screw things up to keep brands from competing with each other. To me, having the brands compete would have been a good thing as it would have forced the various brands to be more innovative, etc. instead the lack of competition has just brought about the sloth and blandness that we've all come to know from GM and its various brands.

The quad 4 didn't come out until the '87 model year, while the Fiero was killed off in '88. The high output Q4 didn't come out until years after the Fiero was dead, unfortunately the timing was off just a bit. Of course, many people have swapped the Q4 into the Fiero, it's a pretty easy swap.

Bryce

Isn't it weird how from the bottom up things like a H.O. Quad4 in a fiero seem like such an obvious production decision, yet from the top down GM can't tell their ass from a hole in the ground.

Or a duramax suburban. Why the hell not!?

Me, I'd be swapping out the 2.5L Iron Duke for the 3.xL Iron Duke they use in boats, and then not tell anyone. The swap would take an afternoon, since it should eb a simple R&R, but you would get some smiles out of it afterwards. Any with plausible deniability you can make anyone you do surprize feel that much worse for being surprized by a 2.5.

great idea. in that vein, that 2.8 they came with, how far is gm stroking/boring that out to these days?

belteshazzar wrote: great idea. in that vein, that 2.8 they came with, how far is gm stroking/boring that out to these days?

The iron block iron head engine came in 3.1 and 3.4 versions, the 3.4 from a '93-95 Camaro is practically a drop in (requires drilling holes for the starter on the other side) and will re-use all of your Fiero external stuff. With that said, I've been there done that and it's not worth the hassle unless your 2.8 is dead and you get a great deal on a 3.4 and want an easy swap.

Of course, with GM's newer V6s they're up to 3900 with the 60° V6. oldopelguy, I've heard that the marine dukes aren't directly compatible with the cars, I just saw a thread about it the other day:

http://realfierotech.com/phpBB/viewtopic.php?t=14016

belteshazzar, perhaps you missed my comment above, but the HO Q4 and the Fiero didn't exist at the same time...the HO Q4 came out a few years after the Fiero had already been axed. Maybe if the second gen Fiero became a reality we would have seen the HO Q4 and the DOHC V6 in there, but it didn't so it's all fantasy at this point. Also, the reason the Suburban never got the Duramax is because it requires a body lift to make room for the Allison trans and all the associated body rework that would be required to keep it looking right and legal would outweigh the extra sales they expected, especially since it would end up being quite an expensive option. In other words, it wasn't expected to be profitable. I'm anxious to see if they stick the new diesel V8 into the new Suburban/Tahoe when that engine comes out, time will tell.

Bryce

i actually have it on authority they won't for awhile. :(

Nashco wrote: The quad 4 didn't come out until the '87 model year, while the Fiero was killed off in '88. The high output Q4 didn't come out until years after the Fiero was dead, unfortunately the timing was off just a bit. Of course, many people have swapped the Q4 into the Fiero, it's a pretty easy swap. Bryce

Ah, I stand corrected. Wasn't there something better than the Iron Duke available at the time, though? The Cosworth from the Vega could have worked, if it had been reliable and still in production. All in all, it was another swing and a miss from GM, like the Corvair and the Vega, etc.