How will big cam respond to boost?
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half-n-half, I think the answer to your question is this: If you use a larger cam and lower boost to achieve the same power level, the chance of detonation is reduced. It is reduced because more compression is done by the piston (100% isentropic efficiency) versus the compressor wheel (70% isentropic efficency). The higher efficiency compression results in a lower temperature at the end of the compression stroke. Lower temperature means it's less likely to detonate.
Mike
Mike
yeah that is definitely the way i was looking at it... however... just because of lower boost numbers, is the air actually going to be any cooler? it is actually more air coming out of the turbo... ehh i guess it isnt the end of the world to know just a little theorizing.
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Originally Posted by half-n-half
just because of lower boost numbers, is the air actually going to be any cooler? it is actually more air coming out of the turbo...
Originally Posted by engineermike
Go back and read the link posted earlier. The cam is fine.
so duration and LSA have a lot to do with an FI application...... and the intake and exhaust lift has nothing to do with it?
i get confused when it comes to cams...... my LSA is 115 and duration is 228/228 with lift at .588 .588
i get confused when it comes to cams...... my LSA is 115 and duration is 228/228 with lift at .588 .588
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Originally Posted by brad8266
I read it and i tend to disagree, there is no solid proof here. Until there is I stand by saying that the torquer is not a great turbo cam.
I guess that's more of a rhetorical question, so there's no need to reply.
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Originally Posted by engineermike
So you're saying that 645 rwhp at 6 psi boost from a turbo LSx is no solid proof that the cam will work?
I guess that's more of a rhetorical question, so there's no need to reply.
I guess that's more of a rhetorical question, so there's no need to reply.
Yeah it works, i get that part, it still doesnt prove much. So what, i have seen a stock engine down to the exhaust manifolds make about 600Hp on like 9lbs, bone stock engine.
Last edited by brad8266; Mar 23, 2007 at 01:36 PM.
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Originally Posted by brad8266
Actually that car seems weak, a big CI/heads/cammed/turbo setup should have made a lot more power than that. Very innefficient setup just like i mentioned.
[QUOTE=engineermike]You said "making the same amount of power", which essentially means "flowing the same amount of air". So, no, there is no more air coming out of the turbo. Also, keep in mind, that heat is added when air is pressurized. If you don't pressurize it as much, then it doesn't heat up as much.[/Q]
yeah i wasnt thinkign straight there...
yeah i wasnt thinkign straight there...
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Originally Posted by brad8266
That GTO setup is inefficient even at 6.5 PSI.
Mike
Originally Posted by engineermike
Okay, when YOU build a turbo combination that makes 650 rwhp at 6 psi boost, get back with us. I've built a few turbo systems and so have many others on this board. Hell, half the guys are calling BS on perdieu's numbers because they are unbelievably high. But, according to you, his numbers are dissappointing. . .
Mike
Mike
But once again there is a stock Z06 here in Savannah that made 585 HP on 9psi, the car is 100% stock down to the exhaust manifolds. That is way more efficient than a head/cam turbo car making 645.
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Originally Posted by brad8266
But once again there is a stock Z06 here in Savannah that made 585 HP on 9psi, the car is 100% stock down to the exhaust manifolds. That is way more efficient than a head/cam turbo car making 645.
Originally Posted by engineermike
If you do the math, the percent hp increase per psi boost is almost identical between those 2, with the "wrong"-cammed GTO having a slight advantage. The ZO6 gained 7.5%/psi, while the GTO gained 7.8%/psi.
The Z setup is clearly a more efficient setup by far. The powerband of the GTO is horrible, doesnt pull down low and drops off way earlier then that cams powerband.
I would take the bone stock Z rear mount setup over the H/C GTO anyday.
granted the Z does have a bigger turbo.
Your buddies head/cam/turbo
The dyno differences are minimal too because I dynoed on that dyno and a dynojet and my numbers were within 2 hp.
Last edited by brad8266; Mar 23, 2007 at 02:17 PM.
LSA does have an effect on overlap, that's why I posted up as a higher LSA and reverse split (IE - Stealth II cam, 224/220 @ .050 on a 116?) would be more in quotes... "Efficient"... People are running decent sized NA cams and getting results just as good, so I'm not sure.
Last edited by 67Firebird455; Mar 23, 2007 at 02:24 PM.