cam question about DCR and a daily driven 383.
11-17-2005, 07:55 AM
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cam question about DCR and a daily driven 383. I am looking into a stroker (383) for my daily driven Trans Am. I currently have what is basically an f13/f14 (i/e) 114+4 Futral cam. I am excited about the idea of using this cam in a daily driven stroker to maintain great low end and idle. I am getting a little concerned about the Dynamic Compression Ratio. With the early closing of the cam, I am getting a DCR of about 9.1:1. I am afraid that might be a little high considering it needs to run on pump gas at a high altitude and will see considerable heat in the summer. Is that too much DCR for what I am doing? I like the idea of a pretty small cam in a stroker, but if I need to move up to be safe on the motor, I will certainly do that. If you do think it is time to consider a new cam, any suggestions would be great.
Any help would be greatly appreciated.
Thanks.
Any help would be greatly appreciated.
Thanks.
11-17-2005, 02:54 PM
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Well, it's actually the sprocket that's adjustable, but you get the idea..
However, I'd try it as is first. For one thing, that 9:1 spec was developed on iron head SBCs. Aluminum can handle at least 1/2 a ratio more in most cases. Second, an LSx engine has sophisticated knock sensors that will save you from any minor detonation, plus, using a scanner to monitor spark retard will tell you if you're borderline. Third, detonation (along with power) is reduced by altitude, which should help, but for the fact that the oil companies know this and so typically reduce octane for higher altitude sale. (Tip: Never bring your pump fuel from Denver to a race in Death Valley.)
However, I'd try it as is first. For one thing, that 9:1 spec was developed on iron head SBCs. Aluminum can handle at least 1/2 a ratio more in most cases. Second, an LSx engine has sophisticated knock sensors that will save you from any minor detonation, plus, using a scanner to monitor spark retard will tell you if you're borderline. Third, detonation (along with power) is reduced by altitude, which should help, but for the fact that the oil companies know this and so typically reduce octane for higher altitude sale. (Tip: Never bring your pump fuel from Denver to a race in Death Valley.)
11-17-2005, 06:47 PM
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Thanks for the help guys. I like the idea of just installing it an monitoring it. I do tend to overthink things, so I will carefully monitor it.
One thing I noticed is, using the same relatively simple but moderately accurate calculator, the stock setup is above 9.4, so I guess GM trusts the design. And well above 9.5 for the LS2.
One thing I noticed is, using the same relatively simple but moderately accurate calculator, the stock setup is above 9.4, so I guess GM trusts the design. And well above 9.5 for the LS2.
