90mm ls6 intake
does any one have it, this is the only thing left that will be restricting my engine. I have headers, ls6 heads, dual springs, 90 maf but the air will still be bottled necked at the intake.
any help would be nice
Did you swap LS6 heads on & leave the stock cam? Or is there a cam not listed on your mods? I'm not seeing enough there to make your LS6 intake be the bottle nack of your combo. Well except your tryin to use a 90mm MAF. What TB are you running? Do you have one yet to bolt to a 90mm intake?
(I have since added Trickflow 215s among other things and will be going to a FAST 102 intake keeping the same 90mm throttlebody.)
If 15 hp is all the difference is I will just keep my regular setup. I was looking into this to see if it was even worth the trouble to do. But I believe with the car I am running it wont make much difference.
Thanks for the advice.
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Before the change, extensive dyno testing (wtih PatrickG doing the tuning "on the fly") indicated the 78mm throttle body, in and of itself, was a restriction such that I was making the same horsepower at 6,500 rom that I was making at 5,200 rpm with the 78mm throttle body. The power curve carried well after 6,500 rm, it was just "flat". The 90mm throttle body showed the 15 hp gain entirely between 5,200 rpm and 6,500.
Before the change, extensive dyno testing (wtih PatrickG doing the tuning "on the fly") indicated the 78mm throttle body, in and of itself, was a restriction such that I was making the same horsepower at 6,500 rom that I was making at 5,200 rpm with the 78mm throttle body. The power curve carried well after 6,500 rm, it was just "flat". The 90mm throttle body showed the 15 hp gain entirely between 5,200 rpm and 6,500.
As I stated in that thread My 78mm FAST with a TB that is compatible with LS6 intake (see my sig) pulls to 6600 rpm with a steady gain in HP (41) 440 to 481 from 5300 rpm to 6200 rpm then flat lines until 6600 rpm where it starts to fall off. The LS6 78mm intake cannot be that inadequate,something else appears to be wrong here. I would say that the cams are highly suspect in both of your cases...no way in hell is it your TB...if that was truly the issue then my engine wouldn't make it to 5000 rpm without flat lining.
As I stated in that thread My 78mm FAST with a TB that is compatible with LS6 intake (see my sig) pulls to 6600 rpm with a steady gain in HP (41) 440 to 481 from 5300 rpm to 6200 rpm then flat lines until 6600 rpm where it starts to fall off. The LS6 78mm intake cannot be that inadequate,something else appears to be wrong here. I would say that the cams are highly suspect in both of your cases...no way in hell is it your TB...if that was truly the issue then my engine wouldn't make it to 5000 rpm without flat lining.
The horsepower curve, which is actually the product of a decreasing torque curve multiplied by an increasring rpm/hp factor, was not merely "considered" to be flat, it was in fat, "observed" to be flat (with the usual minor flucations). We tested various changes to the intake system upstream of the throttle body, none of which alleviated the flat-lined results. The assumption at that point was simply that the combo was exhaust restricted (no headers) and the 90mm intake/throttle body change was actually just an experiment that happened to net an increase in hp.
I have not tested a ported 78mm FAST and therefore cannot speak to whether it is "compatable" (or comparable) to and LS6 78mm intake.











