i have an iron duke 4 cylinder in my fiero and i was wondering if anybody could give me a web site or something that sells performance parts for a fiero or if any one has some used parts or something thanks
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09:35 PM
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nismokidd12 Member
Posts: 302 From: pensacola,florida Registered: Nov 2007
from what i was told and have read. the duke isnt a good performance starter. it doesnt hold to performance upgrades very well and isnt worth the price. which is why i am upgrading to the v6 2.8 and doing some internal mods to it with 3.1 cranks and stuff.if you want power then get a different motor.
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09:59 PM
2.5fierose Member
Posts: 109 From: frazee, mn, united states Registered: Dec 2007
from what i read on this reviews from 84 on the fiero they claimed you could buy a kit from the dealership and get them to push over 200 horsepower im not sure if it was true but if i t was i liked to get my hands on something liek that
Yeah unless you go superduty block and parts (EXPENSIVE!!!) anything more than 120-130hp is prob going to blow that duke. Remember the duke was an economy motor not a performance motor.
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10:53 PM
The_Stickman2 Member
Posts: 1030 From: Lehigh Valley Pa. Registered: Sep 2007
Go to this thread and read my posts. It will tell you what I did to my wifes Duke. I think it has about as much hp as a stock V-6. that is seat of the pants only at this point. Will try to get it on a dyno at some point this year. And it didn't cost alot. And you get a brand new engine, rather than putting a used engine in if you just swap in something.
Fiero Store offers a cam for them. Hooker used to offer a header (you can find them in the mall periodically), Holley offered an intake manifold and throttle body, small block chevy rockers fit, I've also read that small block chevy rods and pistons can be made to work. If you have a 85+ Duke the chevy S10 head bolts on and adds power. Mercruiser used Iron Dukes in their boat motors and had 2.7L and 3.0L stroker cranks but I don't know of any that were successful last buildup I saw with one ended in flames... literally. I think a couple members made them work. That "upgraded" motor from the dealer was the SD4, which are worth a few thousand dollars and are way different from an Iron Duke.
GO here http://ironduke7.tripod.com/index.htm also go to [URL=https://www.fiero.nl/forum/forum2/HTML/074087.html] the duke is my favorite fiero engine you can only do light duty modifications to it .the crank will not take high R P M, do modifications to improve M P G and also improve performance. the best mod to a duke is the S 10 head if you can adapt the S 10 ecm(good luck) you can get a substantial gain in horse power.High performance duke?? equals bad crank.. the junk yards have sent scores of 2.5 fiero,s to japan to make Toyotas,because of a bad bottom end.. the 88 fiero duke 5 speed runs pretty good & gets mpg like a honda civic .. the s 10 head needs different push rods can t remember the stock # .. the advantage of the duke is it is easy to work on and gets great M P G /// the address for the s 10 head will not work just search "better flowing GM heads for the 2.5"
[This message has been edited by uhlanstan (edited 01-05-2008).]
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07:40 PM
Jan 6th, 2008
The_Stickman2 Member
Posts: 1030 From: Lehigh Valley Pa. Registered: Sep 2007
Fiero Store offers a cam for them. Hooker used to offer a header (you can find them in the mall periodically), Holley offered an intake manifold and throttle body, small block chevy rockers fit, I've also read that small block chevy rods and pistons can be made to work. If you have a 85+ Duke the chevy S10 head bolts on and adds power. Mercruiser used Iron Dukes in their boat motors and had 2.7L and 3.0L stroker cranks but I don't know of any that were successful last buildup I saw with one ended in flames... literally. I think a couple members made them work. That "upgraded" motor from the dealer was the SD4, which are worth a few thousand dollars and are way different from an Iron Duke.
Actually It's big block Chevy rockers. Small block Chevy rockers are 1.5-1.6. The Duke is 1.75. Most BBC rockers are 1.7-1.72. What I did was put a big cam in it to make up for the drop in ratio. That way I still get the benefits of the roller rockers and cam even though I lost a bit in ratio.
I just did a duke build with a larger bore, cam, upgraded pistons, etc. I don't know the gain I achieved by the numbers... yet. But I am very pleased with the results I have. Its not huge but still very fun. My car now easily breaks loose in second. do a search for back yard duke build... that is my thread. I bought most of my parts from www.fierostore.com and had a few custom things done at the machine shop.
------------------ Tristan 84 Fiero SE
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08:20 PM
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Jan 10th, 2008
Toddster Member
Posts: 20871 From: Roswell, Georgia Registered: May 2001
I just did a duke build with a larger bore, cam, upgraded pistons, etc. I don't know the gain I achieved by the numbers... yet. But I am very pleased with the results I have. Its not huge but still very fun. My car now easily breaks loose in second. do a search for back yard duke build... that is my thread. I bought most of my parts from www.fierostore.com and had a few custom things done at the machine shop.
Put an intake on that and I guarantee you will be pleasantly surprised. The performance intakes really dont shine unless you have a cam to go with it.
