5.3 turbo cam question
04-24-2011, 10:48 AM
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5.3 turbo cam question ok, so i know the stock cam or the ls6 cam are both really good for a boosted app. but my question is what is a good off the shelf cam that is a bit choppier that isnt gonna kill performance and works pretty well with boost. i dont mind if i lose 20 HP, to me having a "lumpy" cam is worth it. the combo is gonna be blow through and its gonna be automatic so i know that'll make a difference. i know this sounds stupid but any advise is appreciated- Nick
turbo is gonna be an s400 btw and driven alot on the street
turbo is gonna be an s400 btw and driven alot on the street
04-24-2011, 02:57 PM
#3
Pred-Z surprised me again. None of the "shelf" turbo cams I've seen have quite that much overlap. Technically, this cam is right at zero overlap. Which some "shelf" turbo cams are for the SBC, but it uses 1.5:1 rockers, not 1.7:1.
Putting 1.7:1 on SBC supposedly adds 4 degrees at 0.050", so this would be a 224/224, so 4 degrees overlap at 0.050"
Anyway, I guess it could be made to work, with the right tuning.
Putting 1.7:1 on SBC supposedly adds 4 degrees at 0.050", so this would be a 224/224, so 4 degrees overlap at 0.050"
Anyway, I guess it could be made to work, with the right tuning.
04-25-2011, 04:46 PM
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I just spec'd a 231/239 115LSA for a customer with a 5.3 turbo build going into a very light car... The last turbo cam I spec'd for the same builder was 247/253 116LSA, this cam was for a 6.0 in a fox body. It runs 5.40@133 in the 1/8. Both cams have signifigant overlap. The first has 5* and the second has 18*.
There is no best or shelf cam that will be optimal. Your turbo specs, intake manifold choice, comp ratio, gear and tire selection and torque converter choices all come into play here.
Shane
There is no best or shelf cam that will be optimal. Your turbo specs, intake manifold choice, comp ratio, gear and tire selection and torque converter choices all come into play here.
Shane
04-26-2011, 04:18 PM
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Well, there is a point of diminishing returns on too much overlap and boost. It is where it starts bleeding off too much cylinder pressure, more than one can compensate with added boost pressure. From my experience, about 6* positive overlap maximum is a happy medium on a stock cubed motor for the street. On a side note, where you place the overlap has importance depending on the combo being used.
