Assuming that the later engines use the same ECM as 87+ Fiero (1227748) L4... it is possible to use the ECM PROM from at least some FWD cars. Exactly how you do that is determined by which VSS the FWD car used.
I tried this. The swap went well but I tried using a '91 Grand am 2.5L prom and that did not work. The '91 GAs did use the same 748 pcm so I was hoping the prom would compliment the head and intake changes but I just got code 24s and the pcm would not read the Fiero VSS signal, so back to the '87 Fiero prom I went. Too bad because the car did seem tp run a little better with the GA prom. I believe the '91 GA used a magnetic pulse VSS as apposed to the Fiero gear driven.
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12:36 PM
Sep 11th, 2008
OH10fiero Member
Posts: 1541 From: struther OH Registered: Jun 2002
On my first Fiero (an 84).... had an engine fire. Luckily I was able to put out the fire before it burned the entire car..... but much of the wiring and fuel injection was toast.
It was my only car..... so I took a trip to the junkyard and got an intake form a 1980 chevy citation 2.5 and installed it with the 2 barrel carburetor..... and along with the HEI distributor, I was able to totally eliminate the computer.
It actually ran stronger that when it had the TBI...... although fuel economy did suffer a little.
Oh wow thanks for that! 80 Citation intake and the 2 barrel that comes with it right? I'll bet such a set up can be opened up and tuned pretty good.
------------------ 84 Duke, Holley TBI, Manual Trans 4.10, CompuCam, White
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11:12 PM
Rallaster Member
Posts: 9105 From: Indy southside, IN Registered: Jul 2009
What about us 84-86 owners? are we chopped liver or something? If I ever get a 87 or 88 with the 4 and plan on keeping it a 4cyl I will def look into doing this engine mod.
I tried this. The swap went well but I tried using a '91 Grand am 2.5L prom and that did not work. The '91 GAs did use the same 748 pcm so I was hoping the prom would compliment the head and intake changes but I just got code 24s and the pcm would not read the Fiero VSS signal, so back to the '87 Fiero prom I went. Too bad because the car did seem tp run a little better with the GA prom. I believe the '91 GA used a magnetic pulse VSS as apposed to the Fiero gear driven.
This late but... Need to use FWD PROM? No problem. Jump VSS on C203 and ECM. Yes it is the same 1227748. PROM set VSS to use like Fiero or FWD. I wrote a Cave page long ago but didn't post. I still have it. I'll post it now.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
What about us 84-86 owners? are we chopped liver or something? If I ever get a 87 or 88 with the 4 and plan on keeping it a 4cyl I will def look into doing this engine mod.
Rallaster, you can probably omit the ECM and slap a 4 barrel on there if you wanted. Wont do any good without a supercharger but....
------------------ 84 Duke, Holley TBI, Manual Trans 4.10, CompuCam, White
A little late in the thread here, but I am the only one that the pics are not working for?
No. He delete them or other reasons it not online. He didn't use PIP/hostkansas.com to post. Common problem that use any other image to post here. Peoples won't use PIP or FTP to images.fieroforum.com. This happen allot.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
i think it would be cheaper to find an 87 fiero up where i live and pull the engine insted of having it get sent out here. unless you feel kind enough to send it for free! i would think the shipping would cost a bundle for being so heavy.
This late but... Need to use FWD PROM? No problem. Jump VSS on C203 and ECM. Yes it is the same 1227748. PROM set VSS to use like Fiero or FWD. I wrote a Cave page long ago but didn't post. I still have it. I'll post it now.
This is great info!! You guys that are doing this should really try the '91 GA prom (and reading Orge's write-up on this is a must)! I did and noticed a difference in driveability and performance. Unfortunately I did not read Orge's info on the VSS mod when I did it and therefore thought that the GA prom could not work in a Fiero and I threw the prom away. This car has been sold, but if I ever do it again I will definitely swap the prom as well.
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12:13 PM
Rallaster Member
Posts: 9105 From: Indy southside, IN Registered: Jul 2009
Could the bottom end of the motor even handle a supercharger??
Yea sure.....It's good for 150 HP at least. If it blows (and no one gets hurt) Great! all the momma's boy doubters were right! Yahoo!! If it stands it cool...you saved one. Oh, but the engine must be rebuilt to take ANYTHING extra!!!
It's not like you will just throw away the supercharger if the Duke cant take it. One thing about a Duke in a Fiero nobody seems to mention is that the car is pretty light. Not like it's trying to lug a tank around. ------------------ 84 Duke, Holley TBI, Manual Trans 4.10, CompuCam, White
[This message has been edited by White 84 SE (edited 09-14-2009).]
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06:43 PM
White 84 SE Member
Posts: 812 From: Chicago, Illinois USA Registered: Nov 2008
Heck here's my 84 head before I ported it. Maybe the latter heads just did the work for you. No need to feel jipped.
By the way I saw a good amount of room for larger valves... That would flow better majorly I think and there is room to enlarge the compression bowl to bring it back to 9:1 if compression gets too high. A 150 HP Duke can be had it seems like and I think the block and crank can take that in a real way. I'm talking 150 HP not 250 like a 3800 can be made to have. Someone should run #s as to what a 150 motor in a Fiero would be like. I am thinking 0-60 in 7 seconds/ 28 mpg. ------------------ 84 Duke, Holley TBI, Manual Trans 4.10, CompuCam, White
[This message has been edited by White 84 SE (edited 09-19-2009).]
White 84 SE......holy cow man im sitting here looking for research on 84 heads and 3800 engine swaps.... i have two different heads and im contemplating giving up on a duke for a bigger motor.....is there any hope or inspiration to be had? i see that you are porting your own head(are you just matching the gasket and cleaning the inside? or is there more to your process? did you deck(or plain) the head to raise compression? iv heard of thinner gaskets too......
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12:13 PM
White 84 SE Member
Posts: 812 From: Chicago, Illinois USA Registered: Nov 2008
White 84 SE......holy cow man im sitting here looking for research on 84 heads and 3800 engine swaps.... i have two different heads and im contemplating giving up on a duke for a bigger motor.....is there any hope or inspiration to be had? i see that you are porting your own head(are you just matching the gasket and cleaning the inside? or is there more to your process? did you deck(or plain) the head to raise compression? iv heard of thinner gaskets too......
If you want a real performance auto go with the 3800! I gasket matched ported my 84, opened the intake TBI to 2" put in a high lift cam and re bearinged the entire engine. Before I got a pitiful 12 second 0-60 mph, now it's in the 8 second range. No race car but not embarrassing at all anymore( that is on the street-not the track). I'll bet that once I get my odometer to work again I will be getting better than 26 MPG with my "like new" engine. A 3800 is nearly like putting a SD in there cept it's legal on the street. Depends whether you want it for the track or the street. A Fiero can do both.
------------------ 84 Duke, Holley TBI, Manual Trans 4.10, CompuCam, White
[This message has been edited by White 84 SE (edited 09-19-2009).]
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01:12 PM
PFF
System Bot
Mar 6th, 2010
katore8105 Member
Posts: 1519 From: Upstate NY US Registered: Dec 2009
Ah crap, the images posted in this thread have started disappearing! What a darn shame..... I wanted to reference some of the info I had read here before about the s-10 head.......
For anyone still reading this I have a couple of questions. I yanked a head from a 91 GMC pickup today. I have heard that the Grand AM intake is better for the Head than the stock Fiero but how about the intake that was strapped to the Truck head? Also, from what I am collecting, the smaller exhaust ports actually balance the flow of the head. This means that I do not want to port match the exhaust ports but I still do want to do my Intake ports correct?
[This message has been edited by katore8105 (edited 04-17-2010).]
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10:42 PM
Jun 14th, 2010
puddlejumper Member
Posts: 22 From: Vancouver BC Canada Registered: Jun 2010
So any R code head from a 90-93 S-10/15, Blazer/Jimmy head will work. How about the intake from the same. You used a Grand Am because it fit better or easier to find? It was mentioned longer push rods from autozone. Would not S-10 push rods work?
With gas prices the way they are I like the idea of a little better fuel economy.
Great thread.
[This message has been edited by solotwo (edited 07-25-2011).]
If you are thinking of doing this, you may want to wait until I post my build thread. I will post it when I'm finished and the engine is running. I have been taking pictures along the way to document it. But I don't want to post anything before I'm finished (in case it doesn't work). As it turned out, the head didn't fit "exactly", and I had to modify it.
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11:42 AM
PFF
System Bot
solotwo Member
Posts: 5374 From: Grand Rapids, MI. USA Registered: Jun 2002
Did he actually put the head on, or just look at it? And did he use a 90 head? He mentioned 90-93 in his first post, but my head is specifically 91-93 and does not include 90.
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08:58 AM
solotwo Member
Posts: 5374 From: Grand Rapids, MI. USA Registered: Jun 2002
I guess? Yes I read it some were he liked the improvement .
Parts used...
1992 Chevrolet S-10 2.5 cylinder head 1990 Pontiac Grand AM intake manifold use stock Fiero head and exhaust gaskets... use Grand AM intake manifold gasket and a set of slightly longer pushrods MPR-309 (Autozone)
[This message has been edited by solotwo (edited 07-26-2011).]
If I ever get a 87 or 88 with the 4 and plan on keeping it a 4cyl I will def look into doing this engine mod.
