How much power do the AWE/McNeil RSK04 Headers really add???
10-25-2002, 02:05 AM
#16
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The points of peak power gains are in the right places...
If you look at the difference in the manifolds, The AWE/Mcneil manifold is designed for quick spool up and a much higher top end. there are years and years of experience and actual real world results in that manifold/collector layout/design(as used in the porsche turbo realm). Kenny's stuff works and thats the bottom line! If you can have boostin the lower rpms where there was no boost before you get a massive torque increase. If you can raise the volumetric efficiency of the engine by lessening restrictions and run the same boost levels you will have a massive increase in HP.
10-25-2002, 06:33 AM
#17
Your exhaust changes have to have had a big effect too...
...especially on the onset of boost spike, and the top end power increase. According to one person I know, the folks at APR were mighty impressed when they happened to dyno an APR chipped S4 with AWE downpipes due to the amount of torque it produced down low -- *I guess* that means it was more than they expected based on their own experience with APR downpipes. And for high end gains, that 3.5" exhaust has 21% more cross sectional area than the twin 2.25" VM does and 22% less frictional surface area than the twin 2.25" VM does -- that allows a lot more flow.
10-25-2002, 07:38 AM
#19
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Exhaust system mods yielded the big gains. If you want to know what headers do,
compare a stock manifold to header dyno with no other changes. I highly doubt you'll see those kinds of gains with just a pair of headers. Looks like fun though. You found a clutch setup that works yet?
10-25-2002, 07:55 AM
#20
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Re: Your exhaust changes have to have had a big effect too...
<b>Quote: According to one person I know, the folks at APR were mighty impressed when they happened to dyno an APR chipped S4 with AWE downpipes due to the amount of torque it produced down low -- *I guess* that means it was more than they expected based on their own experience with APR downpipes.</b>
I don't know where you heard that. Through our testing, we have come to a few conclusions on downpipes:
a) There are negligible power differences between different downpipe designs and diameters. The main power benefit comes from the removal of the pre-cats which are located in an area of high exhaust gas turbulence.
b) Downpipes will increase peak torque and peak horsepower at the expense of delayed turbo boost onset at lower engine speeds. This effect becomes less noticable at higher engine speeds.
And of course remember any change to intake/exhaust system can have an effect on turbocharger response characteristics which may necessitate a change to the Motronic boost controller (PID settings) for boost stability and to prevent boost overshoots/undershoots.
Brett
APR
I don't know where you heard that. Through our testing, we have come to a few conclusions on downpipes:
a) There are negligible power differences between different downpipe designs and diameters. The main power benefit comes from the removal of the pre-cats which are located in an area of high exhaust gas turbulence.
b) Downpipes will increase peak torque and peak horsepower at the expense of delayed turbo boost onset at lower engine speeds. This effect becomes less noticable at higher engine speeds.
And of course remember any change to intake/exhaust system can have an effect on turbocharger response characteristics which may necessitate a change to the Motronic boost controller (PID settings) for boost stability and to prevent boost overshoots/undershoots.
Brett
APR