ASA Cam Enough Vacuum for Power Brakes?
ASA Cam Enough Vacuum for Power Brakes? 
10-21-2011, 06:40 AM
#4
I have wondered about the vacuum production also with that cam also.
One thing to be aware of is that the GMPP ASA cam has a ton of overlap. It is ground with very long seat timing and has slow ramps.
It took some digging through the archives, but I finally found the advertised duration figures for the GMPP ASA cam.
Advertised Duration @.006: Intake 286° / Exhaust 300° = 73° @.006" Overlap
Duration @.050: Intake 226° / Exhaust 236° = 11° @.050" overlap
Intake .525"/ Exhaust .525"
I made some recent comments about the ASA as a venerable performer in the ls376/515. However, after spending some time looking at the numbers and comparing it with the various Comp lobes, ie XFI, XE, XE-R, LSL, EPS, ect... it kinda makes me want to recall advising anyone to use it as a decent baseline choice...
The @.050 numbers are what seems good, but the .006 numbers are huge, and with the slow ramps I am sure the .200 numbers are not that aggressive/impressive.
- Just about any lobe in the Comp catalog with duration figures similar @.050 / LSA would stomp the ASA.
A similarly spec'ed @.050 cam using EPS intake/PatG exhaust would idle better, generate more vacuum, and would make much more power. Better at every RPM point, and especially under the curve.
(and with those lobes it should have a quiet valvetrain)
Sorry if this is tangential info to your vacuum question.
One thing to be aware of is that the GMPP ASA cam has a ton of overlap. It is ground with very long seat timing and has slow ramps.
It took some digging through the archives, but I finally found the advertised duration figures for the GMPP ASA cam.
Advertised Duration @.006: Intake 286° / Exhaust 300° = 73° @.006" Overlap
Duration @.050: Intake 226° / Exhaust 236° = 11° @.050" overlap
Intake .525"/ Exhaust .525"
I made some recent comments about the ASA as a venerable performer in the ls376/515. However, after spending some time looking at the numbers and comparing it with the various Comp lobes, ie XFI, XE, XE-R, LSL, EPS, ect... it kinda makes me want to recall advising anyone to use it as a decent baseline choice...
The @.050 numbers are what seems good, but the .006 numbers are huge, and with the slow ramps I am sure the .200 numbers are not that aggressive/impressive.
- Just about any lobe in the Comp catalog with duration figures similar @.050 / LSA would stomp the ASA.
A similarly spec'ed @.050 cam using EPS intake/PatG exhaust would idle better, generate more vacuum, and would make much more power. Better at every RPM point, and especially under the curve.
(and with those lobes it should have a quiet valvetrain)
Sorry if this is tangential info to your vacuum question.
Last edited by topbrent; 10-21-2011 at 06:55 AM.
10-21-2011, 07:33 AM
#6
One thing to be aware of is that the GMPP ASA cam has a ton of overlap. It is ground with very long seat timing and has slow ramps.
The @.050 numbers are what seems good, but the .006 numbers are huge, and with the slow ramps I am sure the .200 numbers are not that aggressive/impressive.
The @.050 numbers are what seems good, but the .006 numbers are huge, and with the slow ramps I am sure the .200 numbers are not that aggressive/impressive.
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01-11-2012, 07:38 PM
#13
We have road raced with this combo, works well and is a good performer for a relative low lift cam. I agree though that are better choices, especially for street/strip applications. This combo made about 465 HP at the flywheel in a stock comp 5.7 with unported heads.
