The purpose of this post is to encourage people with 4cylinder Fieros to talk about what they have done to their Iron Duke engines. Deep down inside, the Iron Duke most people consider an economy engine, has the soul of a Super Duty racing engine. The trick is finding it.
I have completed the majority of the modifications I planned for the 2.5L 4cyl Iron Duke that powers my 1984 Fiero.
The gain in power is surprising. It's a different car now, the peak horsepower seems to have moved from 4,000 rpm to about 4,600 rpm which makes highway passing brisk.
Here's the list of mods:
Holley TBI
Holley intake manifold
aftermarket catalytic converter
MSD 6AL ignition
Accel coil
Drilled through air box baffle with 2.25" hole
deburr intake and exhaust passages in head
deburr exhaust manifold at outlet to tail pipe
All the tuneup parts: belts, hoses, sensors, wires, cap, rotor, air filter, fuel filter, transmission filter and fluid, synthetic blend 10W40, . . . basically everything is new
The last step will be to replace the timing gears, install a mild but better than stock roller cam, and roller lifters.
The engine has 95K miles on it and compression is 150 psi in all four cylinders.
While few would put so much effort into an Iron Duke, at this point I have to say it was all worth it.

Can you get some 0-60 times for it? Also, how much money went into these mods?

Even with all of those expensive mods, you will be lucky to put out even close to the output of a 2.8 V6. Read this article from someone who tried to do the same thing...
http://www.homestead.com/Fiero2M4/Modestduke.html

Lucky,

Where did you find the Holly Intake Manifold? I've been looking for one of those for forever for my coupe. I already have the Hooker header that I plan to get Jet-Hot coated and I found a place to supply me with the Holley TBI and so on. This will be my big spring project before Carlisle, but the Holley manifold remains the missing piece in my puzzle.

Yea, I could swap in a V6...but where would the challenge be?

Ken S.
'87 GT and '86 SC
www.westpennfiero.org

[This message has been edited by kslish (edited 03-08-2001).]

I found the Holley intake on the Forum Mall. It was a very lucky break.

Black88GT, the mods were not as expensive as a low mileage used V6 engine, let alone the cost of an entire engine swap. I have found that whenever I mention improving the performance of my 4cylinder, V6 Fiero owners will say "for the money you have spent, you could have a v6 engine"

Right now that is not at all true. There are a lot of reasons not to swap a V6 into a 4cylinder '84 Fiero. Most significant of these is that my 4 cylinder is in great shape, so it does not need to be replaced.

The other thing I disagree with you on is the notion that at best a 4 cylinder can make the power of a stock V6. Depending on how radically you modify it, a duke can put out as much as any 2.8L V6. In fact, a real super duty engine can make as much power as a v8.

The beauty of modifying the Iron Duke is that it is not popular. There are just a few people out there that even care to try. In this way, I find the success I have had with my duke modifications to be most satisfying.

Liking the Iron Duke is not a crime. The duke was the last engine Pontiac designed and built. Your 2.8L V6 is a chevy engine. I have a grudge against chevy, I hate them in fact. So, a V6 will never be found in any Fiero I own. Again, liking the Iron Duke is not a crime.

In the future, I hope that V6 Fiero owners can learn to accept that half of the Fieros have 4 cylinder engines in them. And, some of us are very happy with the way things are.

V6 engines have bad exhuast manifolds. They have broken EGR tubes. Most importantly, they are no where near as easy to work as a 4cylinder on while intalled in the car. Every choice is a compromise, and the Duke represents a fair bargain IMHO.

No matter what car or engine I have, I will try to get the most out of it. I like doing it, it's my hobby.

So, how about letting the Duke owners have a post to discuss the modifications that interest us? That's what this post is all about.

I'll second the motion!!!!!!

here is my mods!
engine bored .40 over
comp cam
holley throttle body
hooker tri y header
three way valve job
new rods-crank-and hypertectic pistons
ARP bolts
high volume oil pump
gt dual exhaust
ram air-eliminated air box-direct tube from side scoop to air cleaner
k and n filter
accell 8mm wires
msd blaster coil!
here is a picure
i am very close to beating a modified v6 fiero on the autocross track-only 3 seconds behind his time every time we race!!!! we some more mods i have planned i will beat him this summer!!!!!!!!!! more power to the hopped up iron ducks!

You'd be amazed at how much 3 seconds is going to cost. 3 seconds in terms of autocross racing is a large gap to overcome.

SloPonti,

I have seen your site describing the engine mods you have done. While the purple and red scheme is not my cup of tea, I like what you have done with your car.

Is .040" overbore working out? It seems like cylinders 2 and 3 are really close together (I have read that the sleeves are flat sided).

Have you ever heard any sound like a souped up duke? It is almost an evil moan right out of hell.

Disclaimer: No, I am not saying the car is faster than a V6. It just sounds like no other engine, like something out of a ghost story or an episode of scooby doo.

Ever wondered why no one soups up the Iron Puke? Many reasons. For one, its not economical. I mean, how many places will a super duty head? How many edelbrock parts do you see for sale? Secondly, the motor was weak. Ever wonder why turbo Iron Puke's disappeared? They were bending rods left and right. The SD4 motor was VERY unreliable for racing. I think I remember hearing the builder John Callies had to replace or redesign 42 different parts to make it last a race. Do you understand how expensive that must have been?

If your talking about performance, the fact that your engine is fine and it doesn't need to be replaced means nothing to anyone. I saw a guy on ebay parting out his perfectly running 52k mile 88 2.8 for a V8 swap. The most Hp you are getting out of a Duck with bolt ons is 120. Hell, the stock 2.8 puts out more then that, not to mention a 3.4.
Weight means nothing either as the 2.8 and the 2.5 weigh the same. I read an article about how in the 80s Pontiac Performance Plus did a thing on souping up the Duck. They added all of these expensive parts, like an SD4 head, Holley TBI, Edelbrock manifold, hooker header. Final output was 200 Hp. Not bad, but at what cost and what reliability? You could take a 3.4 and build it up to 200 Hp easily and remain under the price it would cost for that, not to mention all the extra torque you get and the usable power band (don't have to rev the crap out of it).

V6 Fiero's aren't any harder to work on then 4 cyl's. I had an 88 coupe here that needed work and it had maybe a little more room then the V6 but nothing to go squirrely over.

"I gave up on hopping up Dukes years ago- it was like pissin' in the wind and throwing money down an outhouse hole. Smart and experienced folks like Jim Sutter at IRM tried to tell me back then, but I had to learn the truth my way and ignored their advice. I could have saved a bundle of money if I had listened......
there are several rusting self-destructed Dukes in the corral to serve as a lasting reminder." - Randy Agee

So the bottom line is, learn the hard way.

------------------
Jeff
'88 GT t-top 3.4
Baltimore, MD

Cold summation, Black88GT, but correct. Take it one step further, the 2.8 is a P.O.S. too. Let's face it, the Fiero came from the factory with poor engines. The only real solution is to either keep them stock and deal with the design flaws OR put in a REAL engine.
Cozmo

Hey Cozmo,

You mean like the 4.9 Caddy motor??? Any luck with BubbaJoe? I expect a full update at this Wednesday's meeting.

Roy

Sorry, need to keep it on topic...
The Duke, esp. the DIS ones, are decent engines when in good shape and maintained well. Good low end, gas mileage and reliability if not flogged too bad.
Roy, I'll keep ya posted!
I meant quad4...3.4...3800...4.9...350
all good engines
Cozmo

GT, I think you are missing the point. We know that the v-6 is faster and has more power and is easier to get more high performance parts for. The problem is, it takes a ton of money and an exceptional amount of time to convert to anything else. We aren't trying to build a Winston Cup car, here. We just want to make what we already have run a little better. I have a stroked 2.5 going together right now. All told, I have less than $750 in the motor, and that includes all of the typical machine work that would have to be paid for an a stock type rebuild. Give us a break.

i just can't make myself want to do any thing with the 4 cyl. engine. i already read enough articles and heard enough comments to know it's not worth it to me. i've had a few v8 cars, still have one, and i know i wouldn't be satisfied with what little a duke could be made to put out. i like my fieros. all that i've ended up with so far have been four 4cyls. i try to fix them up as far as my abilities and cash will go (i guess i'm ending up with what would surly be called ricers), but when it comes to a chance at engine performance the plan is to lose the duke.

------------------
Phil T

'87 coupe (feral)
'84 indy
'84 coupe (cheap thrill)
'84 chop top (parts car or project. time will tell)

I don't think there is anything wrong with rebuilding the Duck and throwing on some parts for a little extra performance. But when you try to compare the Duck to any other motor or act like you are building it to be some super performer, your going to flat out lose. When you properly maintain it, yes it might last a decent amt. of time, but name one engine that WON'T! I can name other engines that you don't have to properly maintain and they will still last you forever. Can you say the same thing for Duck's? No way. You miss one oil change and you will pay dearly for it. Same thing happened to a friend of mine with a Cavalier, ended up leaking oil now it takes around a Qt. every 2 weeks. The only reason they put that engine in there was to try and keep fooling the GM Brass into thinking it was an "economy car".

------------------
Jeff
'88 GT t-top 3.4
Baltimore, MD

being in California there are dyno all around you... think you might want to run it?
www.dynojet.com and find a Dynojet center near you.

I'm modding the Duke because it's what I have. I'm sure a V6 is faster but -- from what I've read -- the 2.8 has its share of problems, too. I think I really want a Quad 4 but I'm not up for an engine swap in the near future.

If I can drive a 1958 Volvo for 25 years, maybe I get 200k out of a Duke. And maybe not.

i really hate it when the v6 fieros voice their opinion about the four cylinders are not good-waste of money-you know what it is not your money so let go of it!!! i love my hopped up iron duck and i have had no problems with it! i run it hard but i also do all the maintance to it even before it needs it! so leave the iron duck alone! don't listen to half of what the v6 guys say!!!! i asked all kinds of questions about my four banger when i rebuilt it a year ago and all i heard is it will break-it won't last! they are wrong-when done right like my motor-they last just as long as any other motor! i have not broke anything yet on my car nor has it left me walking either! i autocross the car every weekend and it is also my daily driver-but i just keep up on my motor and car for that matter! sorry to vent like this but i just get tired of hearing you v6 guyes **** about the four cylinder! some people like to be different and nothing is wrong with that!!!!!!!!!!!1
thanks
Rob

Want some cheese with that wine?

I have found Fiero V6 owners are by and large very nice people. Unfortunately, there are always exceptions to the rule.

BlackGT, you have distinguished yourself. I feel insulted by your posts. There was no reason to make it personal or imply that the 4cylinder guys who posted their mods are stupid.

It is a real shame that you cannot allow the 4cylinder guys to be proud of their cars on this Forum.

Where did you get the idea that Duke owners are trying to compete with V6 owners?

But, I am tired of reading about the V6 cars. I have a 4 cylinder and I want to read more about them. Can you really blame me?

Why does a Fiero have to be a 90 or 135HP+ car with nothing in between? Why can't a car go from 0 to 60 in 9 seconds? Do you resent that I recognize no need for a car that does better than 0 to 60 in 9 seconds?

Can you imagine that I might want a car that does better than 0 to 60 in 12 seconds?

Would you suggest that I buy a V6 and detune it to the 125HP I think a Fiero should have?

Why do I need to win races? What's the point of that? Why can't I just make my car sound cool and feel "sporty"?

When you start with 90HP, then adding 5 more makes a big difference. Add 20, and it feels like a different car. If you get to 125HP, then you have increased the output by 1/3. Why shouldn't a 4cylinder owner try to do this? It's rewarding, easy, and it's fun.

The duke blew rods because Saginaw supplied a few lots of crappy ones in 1984. After that, things improved a lot. The chevy V6 is also known to blow rods.

Every time someone says a Duke Fiero is worthless the world hears that all Fieros are worthless. That's why they don't cost much regardless of engine size.

We need to work together to make the 4cylinder cars more desireable to see any gain in value for any Fiero. If a 4cylinder was desireable, then a V6 would only be worth more.

When even V6 Fiero owners say a 4 cylinder car is crap, it makes ALL of us look bad. Most people out there have never touched, let alone driven a Fiero. But they all ask me what I will do when mine catches fire.
Think about it.

On the other hand, if you said "Boy, you Duke guys are making those 4 cylinder cars a lot better" None of us would think we made our cars faster or better than a V6, but we would better respect your comments.

Well the facts are the facts. If you resent facts well then so be it.

You want to soup up the Iron Puke, go ahead, don't let me or any other evil Chevy V6 owner stop you. But when you end up with a blown engine, don't blame anyone or anything but yourself. I'm just saying, look at the guys who have tried to do something with the Puke, look where they got. You have to take past exeperiences and LEARN FROM THEM, so you won't make the same mistake. Which is all I am trying to prevent really, people making the same mistake. Check out that site and read the examples.

When people that have been working on Fiero's for as long as I have been alive are telling me NOT to do something, I think I am going to listen to their advice. It's like when someone says "Grand Prix rims will not fit on Fiero's" yet I go out and buy a set only to pull my hair out trying to get them to fit. Maybe thats not the best analogy but you get the point.

Go to that site that I linked to earlier. Follow the 14 steps it lists for increasing performance on the Puke. You will have made cheap mods that will make it run much better without wasting your money on headers or any of that crap. Or, waste your money on that crap, and I could care less.

Why is it every time an argument comes up someone has to make it a flame war or start taking things personally. I do not have an ego. If I had some big ego I would go out and buy the biggest, baddest V8 I could find, install it in my Fiero then brag to everyone how fast it is or whatever. I have the 3.4 in my car only because my 2.8 blew and I didn't have enough money for anything better.

Remember, you are the one that got all testy when I posted the link to that site trying to prevent someone from repeating someone elses mistakes, so don't try and turn this around on me.

quote Originally posted by Black88GT: Even with all of those expensive mods, you will be lucky to put out even close to the output of a 2.8 V6. Read this article from someone who tried to do the same thing... http://www.homestead.com/Fiero2M4/Modestduke.html

you should have put this message a little less antagonistic(basicaly have some tact.), don't say anything like what you put in you first post(see up) people get offened by that type of remark.

PS. Next time you remark think of someone telling you; you are dieing(that person should have some tact, if not your screwed either way.)

Just some friendly advise.

BlackGT,

If you reread my first post, you will see that the modifications I have made are in accordance with the Fiero2m4 site's recommendations:
http://fiero2m4.homestead.com/IronDuke.html

My expectations were reasonable and my plan well thought out. Your criticism was invalid.

Read what you wrote:

"But when you try to compare the Duck to any other motor or act like you are building it to be some super performer, your going to flat out lose"

Those sounded like fighting words to me.

Was this your intention, or are you trying to protect me from the mistakes you think I have already made (see the first post at top). What's the differnce?

I really hoped that this post would bring out some of the legends of Duke, like SloPonti.

How did you help the Iron Duke owners? I'm just not seeing it. When last I checked, this was the Pennock's Fiero Forum, not the Fiero V6 forum.

As they said in the 80s "get crucial"

It's a quote from "Heather's" a movie starring Christian Slater that was made about a year before they made your 88BlackGT.

You can choose to dwell on our disagreement, but you should still see that movie. It is a amusing, cynical look at teen suicide and high school shootings. It's as well made and provocative as movies like "Raising Arizona" and "Fargo."

Given today's headlines, it's a must see!

I didn't see anything on that page about Holley parts, ignition boxes, or aftermarket cat.'s. But mostly your right you did follow most of what that page said. And about those fighting words, I can only say it my most immature voice "you started it" hehe. Here are some real fightin words for ya

Englishtown, NJ has an All Pontiac Show and Go sometime in May, I think its the 19th. I will challenge anyone with an Iron Duke to come out and try and beat the V6 Fiero's that show up. And not that handicapped racing B.S. I mean actual Qtr. mile times. Any one up for that challenge?

You haven't made any mistakes so far so I guess in a way my criticism was invalid. But when you start throwing around "Super Duty engine" and what not, your treading on thin ice. The SD4 put out around 250 Hp and I don't see any Duke doing that without the help of forced induction, which then raises reliability questions.

So in closing I'm glad this didn't turn into an all out flame war and if you want to soup up the duck more power to you.

An interesting article to read is the Sports Car on Parade in Motor Trend June 1985. In it they built up a super duty 4 banger. In their exactg words, "the four-cylinder in super duty trim has far more tuning potential than the chevrolet built v6". Using Super Duty parts, they were able to crank 180 HP /170 torque out of the Iron Duck which let it reach 0-60 in 6.3 secs. Personally, I think its pretty cool that the ol' 4 banger w. some mods will put most of the imports to shame.

[This message has been edited by loafer87gt (edited 03-10-2001).]

quote Originally posted by mrfixit58: Hey Cozmo, You mean like the 4.9 Caddy motor??? Any luck with BubbaJoe? I expect a full update at this Wednesday's meeting. Roy

Last time i e-mailed him (2 weeks ago) he said he was working on putting another v-8 i for someone, if i remember it was a 84 stick shift. He said he was gonna try to go on the forum when he got a chance cause i guess he has been working alot and has been doing alot of swaps

Kyle

I like my Duke. Yes, you can get 110 HP reliably out of one. I love this, Lucky

quote Have you ever heard any sound like a souped up duke? It is almost an evil moan right out of hell. Disclaimer: No, I am not saying the car is faster than a V6. It just sounds like no other engine, like something out of a ghost story or an episode of scooby doo.

Mine has no cat and ANSA tips, it does sound good...(scooby doo?)
Ya can't beat a V8 for sound, tho...
Cozmo

Ive seen a lot of people put down the 2.8 V6 in many of the threads here, but I personally dont see anything wrong with it. Maybe I dont have enough miles(107K) on it yet? I like the acceleration and the sound it makes. It runs like brand new and Im happy with it. So Duke owners, dont worry, the V6 2.8 gets treated like crap as well. Im glad you guys take care of your Dukes. Keep it up! Black88GT is a person that does not hold back his opinions on anything. I have seen him type some stuff that I would never think of typing, out of respect to others. I dont think he realizes how bad it sounds when he makes some of his posts. I hope I'm right. Thats the way I look at it.

I ran some numbers with Dyno2000 and Dragstrip2000 with what little information I have and came up with what a modified 2.5-liter four could do in a fiero. For a stock fiero with the five-speed transmission I got 0-60 mph in 10.2 seconds and the quarter mile in 17.4 seconds @ 76.6 mph and that was with 98 horsepower @ 4000 rpm and 137-ft. lbs. of torque @ 3000 rpm. A modified fiero like the one with the purple engine might have 132 horsepower @ 4500 rpm and 173-ft. lbs. of torque @ 3500 rpm. With that engine a 2.5 fiero might go to 60 mph in 7.9 seconds and run the quarter mile in 15.82 seconds @ 84.8 mph.

That’s a huge improvement form the stock engine! A modified Iron Duke may not be faster than some supped up v6 fiero’s but it would keep up with or beat a stock v6 fiero. With a super duty duke making 190 horsepower and an 8000 rpm redline that same fiero would go 0-60 mph in 6 seconds and run the quarter mile in 14.2 seconds @ 97.4 mph. You guys make me laugh when you compare the four cylinder to the v6 cylinder engines like it was a war or something. If an Iron Duke is built up properly with high quality parts and the owner is careful when he races the engine an Iron Duke can be a reliable engine (no 150 shots of nitrous). Both the Iron Duke and the V6 engines as with most all early GM engines are totally pieces of cheaply built low quality crap. The v6 is a little better built though. I know that because I rebuild them.

------------------

[This message has been edited by 88formula (edited 03-10-2001).]

All I did to my 4cyl/5sp. when I had it was use an 86 head w/polished exaust ports, removed the airbox and ran 2.5" exaust, no muffler. The guy that bought it from me has an 85 SE V6 auto and claims the 4cyl car is faster.
BTW, the engine was an 87 coil pak deal.I used the 87 computer,86 head and intake, and modified the wiring harness so everything worked together.

The main problem with the 2.8 is the bottom end oiling issues. This is why when 2.8s get around 150k miles, they spin bearings. This is also why when my 2.8 spun a bearing, I replaced with a stronger, more reliable 3.4. Not saying the 3.4 is the best motor ever but they made great improvements over the older 2.8 block and the price is minimal between the two so I couldn't see replacing it with an inferior block.

Yes, as 87GT said, I voice my opinion on everything. Thats just how I am. I like people to know where I stand on things. Its tough on the internet to hear the "tone" of someone or the way they say something, which is a major disadvantage, because I could say something in a jokingly way (which I often do) but people think I am serious and they take offense. It's tough to differentiate when your just reading words. I don't really respect other people who just want to "stay out of things". I think if you have an opinion on something or you think someone is making a mistake, then you should speak up. Hell, we have the 1st amendment, we might as well use it...

Anyone wanna take up my Englishtown Challenge? Were trying to get as many Fiero's as possible this year.

as usual, IMHO

------------------
Jeff
'88 GT t-top 3.4
Baltimore, MD

black88gt-i think that if you are going to post about something then you should post your information on experiance rather than things you have heard or read!! i have said that four bangers can be hopped up and run just fine-SEE I HAVE DONE THIS AND MY MOTOR IS STILL RUNNING JUST FINE-maybe other fiero owners that have attempted to hop their dukes screwed up int the assembly process-i put my motor together in my shop class-this was a required course to get my ASE master tech automotive degree!! so my motor was put together right with correct parts and beefed up parts therefore my motor is good and will remain good-so don't going talking about topics that you no nothing about!!!! because see my car is living proof that the old iron duck can be a hopped up iron duck!! one more thing - don't refer to my motor as the iron puke again-i do not call your car a piece of **** do i? - no - thank you!!
DUKE OWNERS DO NOT TAKE ANY **** FROM A GUY THAT THINKS HIS LAST YEAR MADE V6 FIERO IS ANY BETTER THAN YOUR 4 BANGER!!!

Well, I was not going to reply to this post, but if I "stay out of it" Black88GT will not respect me. I have first hand experience with both the duke and the 2.8, I have owned several of both.

I currently have an '87 GT auto 2.8 and my friend has a 2M4 5spd coupe that I sold him a few years ago. Both cars are mechanicaly stock. Imagine my surprize (and his) when we found out his four cyl was faster than my GT! We raced side by side and he got me by quite a large margin. I could not catch up. He seriously kicked my ass and he could do it again. Oh yeah, he does have a K&N filter and poly dogbone, I guess that's what did it for him. So Black88GT, put that in your pipe and smoke it!

Personally I think the Duke is a better built engine even though it is less powerfull. The 2.8's oiling deficiency is enough of a problem to make me call it a bad engine. I personally have owned three of them that spun a rod bearing at under 100,000 miles and one with a siezed wrist pin at 12,000 miles. But hey, it's because of the 2.8 that I can buy Fiero's cheap, replace the engine, and sell them for a nice profit. I don't see nearly as many 4cyl coupes with bad engines.

------------------
Jon Lagler
'87 GT
4.9 liter V8 Testarossa Spyder (under construction)

SloPonti make sure you take your medicine before you post next time.

Jim Sutter from IRM has been with Fiero's forever. He says souping up the duck is worthless. He knows more about Fiero's then you or I would ever hope to imagine. Randy Agee is another guy who has been around Fiero's for a long time. He too says that not too much extra Hp can be made. S. Joe Wynman is yet another well experienced Fiero guy who says that the duck has its limitations. So, if you think that you know something these guys don't, well then your pretty smart. But these guys also know that when you throw rims on your car lowering springs are pretty much required, so maybe they know something you don't

PENIS

thanks rockcrawl!!! BLACK88GT there you go again talking about what everyone else has done but not from your own experiances!! I SPEAK FROM EXPERIANCE-get a clue man-your the one that needs to take you medicene-man these black 88 gts really are scared about these fourbangers kicken there asses!!!
have a nice four banger day