Cylinder Head Help
Every last part plays into building a car. Displacement, heads, camshaft/valve events, turbo, hot pipe sizing, transmission, gearing, converter (if auto). You can’t just look under the engine bay and point at one part and go “THATS THE PROBLEM” lol
put a PD blower on it and be done if you want a flat curve
put a PD blower on it and be done if you want a flat curve
You'd need to give more details.....so presumably this is not a stock 5.7 bottom end ?
A strong 7500rpm on an LS6 intake is probably doable, but also not the ideal choice. An aftermarket shorter runner intake would make more sense, ProFlo or something.
And camshaft/valvetrain need to be suitable too. 690 lift springs seems a tad odd for a relatively mild motor and mysterious camshaft. In fact...seems just wrong.
But heads...what is your budget ? there are any number of heads these days.
A strong 7500rpm on an LS6 intake is probably doable, but also not the ideal choice. An aftermarket shorter runner intake would make more sense, ProFlo or something.
And camshaft/valvetrain need to be suitable too. 690 lift springs seems a tad odd for a relatively mild motor and mysterious camshaft. In fact...seems just wrong.
But heads...what is your budget ? there are any number of heads these days.
the cam is a comp 54-481-11 and comp rocker arms with a trunnion upgrade comp 26526 spring kit
Nothing fancy, but after a little google action it appears that this would not be an RPM limiting piece, at least not at the RPM I am going for
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That cam is pretty close size wise to a stage 2 turbo cam without the advance ground into most companies use. Tick recommends up to a 96mm turbine wheel. Plain and simple with that cam and a 65mm turbine im sure your 2 to 1 backpressure or more. You need a bigger turbo. S475 96mm turbine on a t4 would make 700 easy and run out to the rpm you want it to. Hell a 7875 vsracing first or second gen will do it. But that baby turbine is your problem in my opinion. Honestly both will most likely spool better also. A 7665 is a **** turbo because of the tiny turbine driving a big compressor. They do work but usually work like what you are describing. Doesnt help that cam discription says for ls3 rectangular port heads and your running cathedral ports. Not big but it isnt best for your combo.
My opinion like doug said get a more bigga turbo.
My opinion like doug said get a more bigga turbo.
Well guys, talked with Precision Turbo and SpeedInc and both of them have suggested that the turbo is likely the issue. Thanks for all your help, learned a lot from this thread. I will have to have a chat with my tuner
I too am trying to build a "light to light" setup that would have quick spool and also have a little more power through the curve. I realized that I would be giving up some power on the top to do so. My specs are 5.3, 7665 turbo, but automatic. Some argue that the 7665 is not the right turbo and something with a larger turbine and smaller compressor would be better, I can agree with that. I do think that a lot of people like the 7665 for street use though.
However, for your manual setup, I'd think you would need a cam that delivers low-end and let a better turbo carry the boost past the cam redline to do its work up there. Could you also use a better rear gear for off the line performance?
However, for your manual setup, I'd think you would need a cam that delivers low-end and let a better turbo carry the boost past the cam redline to do its work up there. Could you also use a better rear gear for off the line performance?
There is so much wrong here, wrong tuner, wrong turbo, probably wrong cam, wrong expectations.
I ran a 7868 turbo and hit the wall at 5800, switched to a 7875 and now makes power to 6600 and trending up so probably to 7K at least.
I ran a 7868 turbo and hit the wall at 5800, switched to a 7875 and now makes power to 6600 and trending up so probably to 7K at least.
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I too am trying to build a "light to light" setup that would have quick spool and also have a little more power through the curve. I realized that I would be giving up some power on the top to do so. My specs are 5.3, 7665 turbo, but automatic. Some argue that the 7665 is not the right turbo and something with a larger turbine and smaller compressor would be better, I can agree with that. I do think that a lot of people like the 7665 for street use though.
However, for your manual setup, I'd think you would need a cam that delivers low-end and let a better turbo carry the boost past the cam redline to do its work up there. Could you also use a better rear gear for off the line performance?
However, for your manual setup, I'd think you would need a cam that delivers low-end and let a better turbo carry the boost past the cam redline to do its work up there. Could you also use a better rear gear for off the line performance?
Gears actually hurt performance on a turbo car as it provides less load to get the turbo going.