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1982 ECM & Compression

Old 08-16-2018, 08:44 AM
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Tslayer66
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Default 1982 ECM & Compression

As i narrow down the best performance cam and heads for my 82, doing my research on this forum and other sites. I thought i saw somewhere, but now can't seem to find it again that a compression over 10:1 would cause problems with the ECM. Is there any truth to this or did i imagine it? If it is true, would an aftermarket ECM help in any way. I know my choices are limited for this year and have read mixed results with the performance ECMs.

Appreciate the help!
Old 08-16-2018, 01:54 PM
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MelWff
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If you changing the cam and heads already why arent you installing a non-ecm distributor and switching to a carburetor?
Old 08-16-2018, 03:09 PM
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Originally Posted by MelWff
If you changing the cam and heads already why arent you installing a non-ecm distributor and switching to a carburetor?
Yeah that is a good question, I have seen this discussion before on the forums with many different opinions. So... right now i am evaluating my options...At first I thought I was going to stick with the Cross Fire and add mild cam and heads. Want to keep it a good driver with a little more power and the cross fire is unique with this particular year so keeping it if i can make it work makes sense. Now as i get more into it i realize the cost to do what you have suggested would really be about the same and I could get much more power. I still need to decide and as i get answers to these questions it will help me make that decision.

Thanks!
Old 08-16-2018, 04:00 PM
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Fast81
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Here's my recipe for a hotter 82:

Summit (dart) heads #152123 -- 72CC, 165 runners
Renegade intake
Lunati Voodoo cam 60100
Hypertech chip
1985 fuel pump (ep241)
delete cat
HEI perf tune

your L83 is already a 9:1 motor so you cant go much higher with iron heads on pump gas

Last edited by Fast81; 08-16-2018 at 04:06 PM. Reason: more info
Old 08-16-2018, 11:50 PM
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terry82
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I like that you are trying to stay with the crossfire.get all you can out of it .then tell us how far you got with the factory set up .Then I would get what ever manifold you like and put a fast fuel injection on it. what hp are you hoping for?
Old 08-17-2018, 07:41 AM
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Tslayer66
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Originally Posted by terry82
I like that you are trying to stay with the crossfire.get all you can out of it .then tell us how far you got with the factory set up .Then I would get what ever manifold you like and put a fast fuel injection on it. what hp are you hoping for?
HP would just be a guess, if I can get into the mid 13s then I would be happy. For a street ride that’s not bad. I’m ready to order the parts if I can get a question to this compression and ECM question. Right now I’m right at 10:1 with the changes I will be making.
Old 08-17-2018, 10:50 AM
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derekderek
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Aren't you replacing 72 cc heads with 72 cc heads? Where is the extra compression coming from? Oh, somebody else, not OP with the Summit heads.

Last edited by derekderek; 08-17-2018 at 10:53 AM.
Old 08-17-2018, 11:49 AM
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Fast81
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82 OEM 426624 heads are 76cc chambers (1960s design) with 158 cc intake ports

Summit (dart) heads are 72cc chambers (modern 'heart' design) with 165cc intake ports

Last edited by Fast81; 08-17-2018 at 11:55 AM.
Old 08-17-2018, 12:28 PM
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Tslayer66
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Originally Posted by derekderek
Aren't you replacing 72 cc heads with 72 cc heads? Where is the extra compression coming from? Oh, somebody else, not OP with the Summit heads.
Currently looking at 64cc heads with .03 gasket which will put me around 10:1. Trying to get good compression without wigging out the ECM but I can’t seem to find out if it will be a problem. Have not ordered any parts yet
Old 08-17-2018, 05:09 PM
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Fast81
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Tslayer -- you REALLY need to PM CF member "Buccaneer", he WILL know what the stock ECM limits are as he has pushed them all.
Old 08-18-2018, 12:10 AM
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Gunfighter13
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I started with a mild cam, 64cc heads (I used RHS 200 runners with 64 cambers with .041 Felpro gasket), Stainless mid size headers, ported stock intake and Hypertech chip. I also rebuilt the throttle bodies. Really wakes up the stock motor and it still will cruse anywhere you care to go.
Old 08-18-2018, 12:25 AM
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7T1vette
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There is no reason to dump the ECM and other engine control stuff just because someone else can't deal with them! As long as the stuff you put on that engine can produce the proper fuel/air ratio for the engine (as read by the O2 sensor), the ECM system should work just fine. If you want to build a 500+ hp screamer with 12:1 compression and which needs AV gas to run, maybe you want to start with something other than a CrossFire engine. If the ECM and components are in working order, you can change heads/cam/pistons/exhaust/induction system and it will work just fine.

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