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safe timing?
What is the max safe timing i can use on a 7.4l with the gm performance aluminum heads,10:1 compression wich i think the heads bump up to 10.7:1, and the zz502/502 cam. running 93 octane.
heads are combustion chamber 110cc runners are oval 290cc cam specs are 224*/234* .527/.544 at 110 lsa Thansks. |
34 total advance, I wouldn't any higher than 36.
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36
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unless you have modified your pistons or deck height you're not at 10:1 and definatly not 10.7:1 on a 454.
with a 110cc combustion chamber and a stock pistion that still sits .020 in the hole you're around 9.5:1. In any case 36 is still where you wanna be. DAVE |
Originally Posted by Dave F
(Post 2173311)
unless you have modified your pistons or deck height you're not at 10:1 and definatly not 10.7:1 on a 454.
with a 110cc combustion chamber and a stock pistion that still sits .020 in the hole you're around 9.5:1. In any case 36 is still where you wanna be. DAVE Is there a way to check what my compression really is? |
32 degrees is safe. 34 is ok as well , but with all the ethanol in the fuel these days,,,, .
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You never know where you might be and need gas and all you can get is crap, I like the 34 mark myself. Especially if your not an all out need every ounce of HP you can get kinda guy.
John:D |
Originally Posted by BY U BOY
(Post 2173363)
Im running the srp 10:1 dome pistons.
Is there a way to check what my compression really is? your head gasket will say the same on the package. If you're using a fel pro 1037 I believe thats a 10.9 cc and lastly you already know your head is a 110. So with a piston volume of: -20cc = 10.7:1 @ 96cc total -15cc = 10.2 @101 -10 = 9.8 @ 106 Just to give you some rounded figures DAVE |
I have no idea...but my builder wanted it at 32 so there would be no problems!!!!!!
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Originally Posted by Dave F
(Post 2173635)
Ah! Now it makes sense. As far as calculationg CR your piston card should have the amount of cc's it is at TDC. In your case it may be a negative number.
your head gasket will say the same on the package. If you're using a fel pro 1037 I believe thats a 10.9 cc and lastly you already know your head is a 110. So with a piston volume of: -20cc = 10.7:1 @ 96cc total -15cc = 10.2 @101 -10 = 9.8 @ 106 Just to give you some rounded figures DAVE |
Originally Posted by t500hps
(Post 2173688)
I have no idea...but my builder wanted it at 32 so there would be no problems!!!!!!
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the true way to adjust your timing is to start at a point. In this case I believe we can all agree that 32 is totally safe. check speed,rpm and overall performance.
Move it up 2*. If performance/rpm increases, great. Move it 2* more. If performance/rpm stay the same go back 2* and lock it. DAVE |
FYI, to those interested, here is a link to a web site that you can calculate all kinds of things, inc. comp ratio, total CI and other things.http://www.golenengineservice.com/html/calculators.html
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Originally Posted by hoozeyurdaddy
(Post 2173886)
FYI, to those interested, here is a link to a web site that you can calculate all kinds of things, inc. comp ratio, total CI and other things.http://www.golenengineservice.com/html/calculators.html
Thanks for the link:D |
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