LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

What CR to go with

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Old Feb 11, 2004 | 06:22 PM
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1984camaroz28's Avatar
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What CR to go with

I no LT1s can run a higher Compression then a normal SBC what CR can i run in my LT1 running pump gas 93 with no problems
Old Feb 11, 2004 | 06:31 PM
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some engine specs?
Old Feb 11, 2004 | 06:38 PM
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1984camaroz28's Avatar
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383 stroker 64cc alum heads around 500 lift cam NOs injected
Old Feb 11, 2004 | 07:15 PM
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The most important thing to know is the duration numbers for the cam. The longer the duration on the cam, the more static compression you can run. In a way, static compression is really meaningless. You have to specify when the valves open and close to get the dynamic compression ratio. That is the number to look at most. Be sure you use the advertised (0.006" lift) numbers and not the 0.050" lift numbers.

I run 11.8:1 compression on 91 octane California MTBE gas, but that is with a 282/288 (@0.006" lift) cam.

BRAD
Old Feb 11, 2004 | 07:37 PM
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Originally posted by llafro
The most important thing to know is the duration numbers for the cam. The longer the duration on the cam, the more static compression you can run. In a way, static compression is really meaningless. You have to specify when the valves open and close to get the dynamic compression ratio. That is the number to look at most. Be sure you use the advertised (0.006" lift) numbers and not the 0.050" lift numbers.

I run 11.8:1 compression on 91 octane California MTBE gas, but that is with a 282/288 (@0.006" lift) cam.

BRAD
What he said.

But if you dont have the resources to compute your dynamic CR, shoot for around 11:1 and you will be totally safe on 92 up. From what it sounds like you have a small cam, just based on the lift, but if you have a rather large cam, 306 or bigger, you could technically run higher SCR, ive seen 13 running on pump gas before.
Old Feb 11, 2004 | 08:31 PM
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so 11 to 1 and i will be total safe... i havent picked a cam yet
Old Feb 11, 2004 | 09:27 PM
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Originally posted by 1984camaroz28
so 11 to 1 and i will be total safe... i havent picked a cam yet
Pick the cam and then build the CR based on the cam specs.

Rich Krause
Old Feb 12, 2004 | 12:56 AM
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Originally posted by 1984camaroz28
so 11 to 1 and i will be total safe... i havent picked a cam yet
what are the specs of the heads?
Old Feb 12, 2004 | 01:25 AM
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im gona use the trick flow heads..... what cam should i go with
Old Feb 12, 2004 | 09:58 AM
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Sorry, but ya cant pick a cam based on 383, trick flow heads, 64cc chambers, and NOs injected.

Talk to someone who knows what they are talking about with cams. Get ahold of Bret (sstrokerace) or Joe Overton (joes94ta?). They are two people I know of on this board who grind their own cams, the Comp Cam custom grinds are only about $40 or $50 more than an off the shelf cam, and Joes Steel billet custom cams are $400, but well well worth it in my eyes...not sure if Bret does steel billet cams, but if so talk to either of them.

This is your absolute best bet, people might tell you a 306 or a XE236/242 or hundreds of other off the shelf cams that would work with your combo just fine. But until you tell a cam grinder absolutely everything you know about your engine/car, even things you dont know, you wont have a matched cam.
Old Feb 12, 2004 | 10:10 AM
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11.48:1 right here on Nevada aka California 91 octane, I am ok in the summer with 120 degree heat.
Old Feb 12, 2004 | 11:21 AM
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i dont no man im running 10.5 to 1 in my big block and over a 600 lift cam....
Old Feb 12, 2004 | 11:31 AM
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11.83:1 on Ohio 92 octane, no knock retard at WOT. You can run over 12:1 safely on pump gas with the right tuning, but sometimes maximum possible CR may not always be the best for your application.
Old Feb 13, 2004 | 01:50 AM
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nitrous+compression=




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