New owner, 4 Cyl, performance questions.

As my signature suggests, I am buying a Pontiac Fiero, the first body style, and I would like to enhance performance for this vehicle. I have a heavy foot, but due to a court decision, I need to maintain SR-22 insurance 3 years and I need the car to maintain for most of those years, preferably all. I constantly speed and is there anything I can do to the car so that I won't risk the engine imploding everytime I floor it? I heard pistons, rings, valves, springs, and such help, anything that someone knows will give first? Also, are there body kits available for a 1st Gen Fiero 4Cyl?

The stock built 2.5L L-4 Pontiac "Iron Duke" Is a very dependable engine, but only when "treated properly" aka not beaten at a constant rate. Under a heavy foot they tend to die out rather easily. The least expensive way to make them lead-foot proof is to replace rod, main, and cam bearings as well as the timing gears with counterparts from the Pontiac Racing 2.5L super duty four engine. Replace the head gasket and head bolts and have the head profesionally checked for warping, cracks, valve leaks, and any excess wear on the rocker arms, ball studs, and pushrod guideplates. The pistons and rods normally hold up well but should be checked as well. New rings are a good idea - CrMo is recommended. Cylinder walls should be checked for wear, ridge, scoring and out-of-round. Main bearing line bore should be checked while the engine is apart, and the crankshaft and camshaft should be checked over, too. It's not required but a wise idea to replace the lifters. (hydraulic on 84-85, hydraulic roller type on 86-up) Be sure the distributor and EST are working properly and ignition timing is correct.

The above will restore lost power from engine wear but won't give you anything extra, just insurance that it can take a beating and still hold it's own.

Most body kits are made to fit all Fieros, notchback or fastback, 4cyl or 6cyl, first or second body design. The steel unibody under the plastic never changed through the car's 5 year run, with the exception of a few minor modifications to the suspension to body mounting on the 88.

Okay, thanks. I appreciate the information that you gave me for the Fiero. My mom doesn't want me to buy it, because she thinks it will be a black hole for repair work, but now I know to chill with it, because it probably isn't built yet. I have read a couple webpages that I saved on my computer on Iron Duke performance, so I have found out enough to convince me to keep the 2.5liter in it, but could I switch in a 2.8liter from a S-10/Blazer and build that engine for performance? I know of a junk yard near me where they have several 2.8's from the S-10/Blazers for 125 or so. I am pretty sure that their transmission won't work, but what car's trans. can I use for the swap? I think I've seen a 3.1liter Celebrity their, and I've heard the 3.1 and the 2.8 are quite similar.

An 86-up S-10 2.8 is the same as the Fiero 2.8 (minus the bitchin cherry red intake plenum found only on Fieros) except the starter is on the opposite side of the engine. This is easily fixed by drilling and tapping starter bolt holes on the correct side. 85 and older S-10's have a 2 bbl carb instead of MFI but are a direct bolt in, too, once you move the starter.

I'm guessing you have an automatic in the Fiero you're buying - If so it's a Turbo Hydromatic (TH)125 T3, and will fit not only a 2.5 but also a 2.8, 3.1, 3.4OHV, 3.4DTOHC, 3.8, 3100, 3400, 3800, or 3800 II so a new tranny isn't needed. If you'd rather have overdrive a TH 440 T4 (later renamed TH 4T60) Will work with the GM V6 family too. Stay away from the TH 4T60-E, the E stands for electronic controlled valve body, and they don't work right in anything but the cars they were programmed for - In fact my 95 Beretta 3100 had one and it was good for s*it despite the fact the computer was programmed specifically for a v6 Beretta.

FYI: you don't need a rear spoiler on a Fiero - you don't want extra rear downforce. At high speeds the front end tends to lift off the ground enough to make the car very difficult to keep under control. A wing on the back only makes this worse. A chin spoiler, on the other hand, is a good investment.

Okay, just for a helpful figure, what should I expect the top speed of my stock 2.5l Iron Duke Fiero that is running in good shape?

hmm...well my 87 gt 5 speed has been to 150 and my auto 3 speed 86 se to 140...i say you could get it up to at least 120...is it an auto or manual?

The car is a stock, base model Fiero. I started it up recently and I was pleased. It sounded close to my dad's 2.5l S-10(similar engine).

I had my 4 up to at least 110, and it needs plug wires. It didn't get there too fast but it got there.

Oh okay, I just wasn't sure because when I was driving my dad's Iron Duke powered S-10, I top'd out at about 87-90mph on flat land.

The s-10 is heavier, but has no weight over it's driving wheels, it's geared lower for pulling, tuned for more torque(which means less top end) and it has the aerodynamics of a brick wall.

Oh yeah, I sort of forgot. Well, do you think you could provide me with a list of things that would need to take from the donor junk yard car that I would be pulling it from. I was thinking of pulling the V6 from a 90-ish 3.1l V6 Chevrolet Lumina. I read that they have a 4 speed auto. in the automatics, so I wanted to try to get that one to replace the 3 speed(ill). I am not sure, though. How would a car with a 3speed get to 110 without really wide gears?

For a 3.1 you will need the engine, ecm, underhood harness and related sensors. The 3.1 is quite similar to the 2.8, it's the same 60 degree v block with a bigger bore and stroke, and carries the same multi port system. The transmission ( In a 90's OBD I Lumina, it'd be a 4t60 ) Will mount in without too much trouble. You'll have to figure out a shift linkage of some sort - a stock fiero cable will probably cut it but the shifter, labeled P R N D 2 1, will become P R N OD D 2, aka no manual 1rst gear, unless you find a shifter to swap.

MY car is a 5 speed manual - but as for the 4-cylinder 3 speed automatics getting to 110 - you are so right - maybe if they were rolling down a BIG hill. Like Mount Everest for example. Turbo 125's suck :)

Uh, what's a Turbo 125? Is that a specific trans.? I just know that it was Probably a 3 speed auto. I haven't bought the car yet, but now I am definite on purchasing it, I am through dealing with my dad's vehicles and I want to start fresh with my own, although I will be passing up a 95 Dodge Neon for a less roomier 8? Fiero. However, I am going to do it. He's the main reason my license is suspended. When I get it, I will post some pics from a 2.1 megapixel camera.

Oh yeah, just to check, did you get the part where I am switching from the 2.5l Iron Duke to a V6?

Tubro Hydromatic 125c, a very common GM 3 speed automatic transaxle. Acording to the option codes, it's possible to have a turbo 200c 3 speed in a Fiero but I think it was only used with v6 cars...

Yea, I caught that you were swapping a V6 into a 4 cylinder car. You may need a few odds and ends, like Fiero specific engine side motor mount brackets, but those are readily available from both new and salvage sources.

I should mention you should be comfortable with DC electricity, soldering, and basic electronic multi port fuel injection principals before attempting the swap. The 3.1 L Multi Port is one of the easiest non-original engines to put in a Fiero but some bugs will usually show up.

Alright, thanks. Good news, the time for me to buy the car is drawing near, and I have also found a Chevy Lumina with a good motor/bad tranny that I could use for a donor car. 300 bucks. I should be able to get all those parts from it, and maybe pull some parts that I could sell easily and try to get some $ back from it. I guess it's not a bad idea, but I would be stuck with a 3 speed auto until later. I thought about not being to shift to 1 in the tranny, and I think I will be alright. I don't move the stick through the gears on an auto, just hit OD and go. Well, thanks for your help, I wish I could do something in return. I have faith in the 3.1 swap, though my friend says his 3.4 swap in his S-15 would stomp the Fiero. I'll post some digital pics from the race if we do. Well, that's all.

Okay, I took a trip to a local junkyard that I know to be incredibly cheap and I walked down the GM section to find several 3.1's, 2.8's, and even 3.8's. Now, I was going to have my brother work on it, since he is a hobby mechanic, however, his solitary confinement to Hondas says he refuses to lay a wrench to the Fiero for me, so I am wondering which would be the easiest: the 3.1 or the 3.8? I can change an oil and I am excellent at taking things apart(as in I can figure things out pretty good), I just have never wrenched on anything past taking a valve cover off. Do you think I could do the engine swap myself possibly? I can gain access to tools/buy a few. I could also try to work in this Military Auto Hobby shop which has all the tools already there. Also, has anyone seen a performance shift kit for an auto. 4 cyl. Fiero?

My suggestion, considering you've never pulled an engine out before, would be to go with a direct Fiero to Fiero swap. Check out the 4 cylinder to v6 conversion kit on http://www.kickhill.com/mechelec.html

for $850 you get everything you need to install a V6 in your Fiero, including the 2.8L V6 itself in good running condition!!!
Pick yourself up a $20 Haynes or Chilton's Manual for some usefull step by step procedures and helpful illustrations.

I'm saying this because the price is quite reasonable and it saves you all the normal engine swap hassles of tracking down every thingamajig, doodad and whatchamacallit required to get it all working. (not to mention trying to talk any normal salvage yard into pulling an engine without totally destroying the wiring harness is more frustrating then digging a ten foot hole in solid granite using a pair of tweezers)
As a newbie to complex automotive work, you need all the breaks you can get. Later on, when you mess around with your Fiero and learn more (the only way to REALLY learn is to climb under the decklid and just get down and dirty with it.) You can improve things even more by adding performance exhaust and upgraded ignition, modifying the air induction system, rebuilding the engine (a 2.8 can be bored and stroked to a 3.4L and perhaps even more) and adding high performance internals, N2O, turbo/superchargers etc. You may even pull that 2.8 out altogether and move on to a 3.8, or maybe a 350 or even a 455!! Don't be afraid of taking your time deciding how you want it all to be done, that's how true enthusiasts do it. In fact, I bought my first Fiero this spring and I'm still working on my engine design. I have a shortblock V6 together so far and I've changed the final engine design 9 times already!!
Try not to get in over your head with your first project, but do something that will challenge you and help you learn so you can get creative later on.

If you get a ticket with the iron duke, thats an accomplishment =). When I had the 2.5 in top speed was straight down on the speedo, (105ish?)
Your best bet is to absorb as much information as you possibly can. Read everything, learn from others mistakes. As far as engine suggestion, do what you want. Next time I want to do a L67 swap (turbocharged 3.8L). If you've NEVER wrenched before, an engine swap may be a little intimidating. There is going to be a LOT of trial and error. In all honesty, you have your SR-22? May be you should wait till that expires before you make a speed rocket?

I found a way to get out of the SR-22 thing, so things are looking actually possible plus I found a friend who will be willing to let/help me work on the car in his equiped garage.

I have a 84 fiero 2M4 (2 seats, mid engine, 4 cylinder) four speed transmission and i am wondering if a 2.8L fiero GT motor will bolt up if it is what years will allow me to do this. Or if this isnt possible what other motor swaps (on a budget) could i do to get some kick in the pants fun out of this car. I am a experienced mechanic so all motor swaps i can do would be greatly appreciated.

Thanks for the help

hmm...well my 87 gt 5 speed has been to 150 and my auto 3 speed 86 se to 140...i say you could get it up to at least 120...is it an auto or manual?

I call :bs:



The max I could get my 5 speed 2.5 iron duke up to was 100-103 (since the speedo cuts off at 85)