502 MPI Headwork and camshaft = how much hp?
08-02-2003, 09:51 PM
#1
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502 MPI Headwork and camshaft = how much hp?
Okay, my eyes are tired from reading all the camshaft and headwork posts I could find!
Dennis Moore and JimV seem to have the answers but anyone else feel free to jump in here.
I have a 1995 502 MPI completely stock and like all of us I want more power and speed.
How much horsepower can be gained from having my stock heads worked and a camshaft change while leaving the ECU alone? Will I have to go to aftermarket exhaust? I want to keep RPM's under 5200 because I run wide open for long peiods of time and I want to be able to run silent choice at idle(if that is possible).
What kind of realistic hp gains can be obtained?
Dennis Moore and JimV seem to have the answers but anyone else feel free to jump in here.
I have a 1995 502 MPI completely stock and like all of us I want more power and speed.
How much horsepower can be gained from having my stock heads worked and a camshaft change while leaving the ECU alone? Will I have to go to aftermarket exhaust? I want to keep RPM's under 5200 because I run wide open for long peiods of time and I want to be able to run silent choice at idle(if that is possible).
What kind of realistic hp gains can be obtained?
08-03-2003, 08:35 AM
#4
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Has anyone ever had the intake redone by Extrude hone. If I am saying it correct? It's where they squeeze a compressed abrasive through it acting like a polisher. I know lots of guys with mustangs do it to their intakes to flow air better
08-03-2003, 12:05 PM
#5
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502 efi upgrades
black hawk az speed and marine has something called "short runner manifolds" they have an exchange program where you send in your stock intake manifold and they send you one already machined out . i have gone through this 502 efi upgrade thing over and over and decided for the $$ and performance you can't beat the super chargers !! i decided on the pro charger m3 running 3psi boost 89 octane fuel and get at least 580hp!! can't beat it for perf. and reliability!!
08-03-2003, 01:02 PM
#6
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The intake runners on the 502 EFI are huge for an engine running at only 5,200 rpm. It almost seems silly to suggest making them larger. The engine can only pull in as much of an air/fuel mixture as the intake valves and the intake camshaft lobes will allow. The camshaft is the restriction to the air/fuel mixture moving into the cylinders on this engine.
You can increase your power considerably by changing the camshaft to one that opens and closes the valves faster. Keep with the same intake duration specs at .050 (as the stock camshaft) but with a faster opening and closing rate. Add about 6 degrees more exhaust duration. Tighten up the lobe separation angle to 110.
I suggest the Comp Cams Xtreme Energy XE 268H it has 224/230 intake/exhaust duration, .515/.520 intake/exhaust lift and a 110 LSA. It will work with the stock MEFI program, the stock valve springs and not require adjustable rocker arms.
It will give you an excellent performance increase (25-35 horsepower).
If you feel you need head work, increase the intake valve diameter and concentrate all of the work into the area where the air/fuel mixture passes the intake valve and enters the cylinder (the valve bowls and seats). This area is the only restriction to air/fuel mixture flow in a low rpm big block with rectangle port heads.
Sincerely
Dennis Moore
You can increase your power considerably by changing the camshaft to one that opens and closes the valves faster. Keep with the same intake duration specs at .050 (as the stock camshaft) but with a faster opening and closing rate. Add about 6 degrees more exhaust duration. Tighten up the lobe separation angle to 110.
I suggest the Comp Cams Xtreme Energy XE 268H it has 224/230 intake/exhaust duration, .515/.520 intake/exhaust lift and a 110 LSA. It will work with the stock MEFI program, the stock valve springs and not require adjustable rocker arms.
It will give you an excellent performance increase (25-35 horsepower).
If you feel you need head work, increase the intake valve diameter and concentrate all of the work into the area where the air/fuel mixture passes the intake valve and enters the cylinder (the valve bowls and seats). This area is the only restriction to air/fuel mixture flow in a low rpm big block with rectangle port heads.
Sincerely
Dennis Moore
08-03-2003, 01:21 PM
#7
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Dennis, thanks for the reply. If I have my heads done I will definitely have JimV do them. If I do the heads and camshaft what kind of hp increase could I see? What if I switched exhaust too?
Also, I remember in a couple of threads you suggested the Edelbrock 5062 which has .527 intake and .553 exhaust lift. Would this give me a little more power or seeing that it is a 114 LSA would it be about the same as the Comp Cam?
26Sonic and BUDAH, I have seriously considered a whipple and running it at low boost to save the drive. But, there is one small problem, it's way to easy to increase boost and hp! I know that I will want more after a short period of time and if it's that easy I'll do it!
Also, I remember in a couple of threads you suggested the Edelbrock 5062 which has .527 intake and .553 exhaust lift. Would this give me a little more power or seeing that it is a 114 LSA would it be about the same as the Comp Cam?
26Sonic and BUDAH, I have seriously considered a whipple and running it at low boost to save the drive. But, there is one small problem, it's way to easy to increase boost and hp! I know that I will want more after a short period of time and if it's that easy I'll do it!
08-03-2003, 01:38 PM
#8
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BUDAH, I am not concerned with holeshots because I baby it now. What I am concerned with is getting air under my props at high speed which can be east to do in sloppy water with the blackhawk drive since it is so short. Another problem is prop choices for my drive. I would probably have to regear to a 1.36 which would be even more $$$. Believe me, I would love to do it, I just don't have the $$$ for all of it!
I guess what I was looking for is a little more hp and a few mph while keeping my gearing and the drive fairly safe.
I guess what I was looking for is a little more hp and a few mph while keeping my gearing and the drive fairly safe.
08-03-2003, 03:26 PM
#10
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Budah
I would think the camshaft would be good for a 2 or 3 MPH increase if he reprops the boat. The head work wouldn't make any more horsepower, but he could brag about the expensive heads on his boat! If he changes the exhaust he will have to reprogram the ECM or (at the least) increase the fuel pressure.
Sincerely
Dennis Moore
I would think the camshaft would be good for a 2 or 3 MPH increase if he reprops the boat. The head work wouldn't make any more horsepower, but he could brag about the expensive heads on his boat! If he changes the exhaust he will have to reprogram the ECM or (at the least) increase the fuel pressure.
Sincerely
Dennis Moore
