n/a cams working against turbo setup???
07-03-2006, 09:50 AM
#11
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Join Date: Feb 2003
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Re: n/a cams working against turbo setup???
Originally Posted by z1guy
too much overlap is going to let pressurized air fuel mixture escape through the exhaust period.
07-03-2006, 11:11 AM
#12
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Thread Starter
Join Date: Jul 2006
Posts: 12
Re: n/a cams working against turbo setup???
rite i undersy=tand wot you guys r saying now
so wots my remmedy? i aint turning the boost up till end of the year that time ill have a built block
so you think i should give the skunk2 turbo cams a go?
so wots my remmedy? i aint turning the boost up till end of the year that time ill have a built block
so you think i should give the skunk2 turbo cams a go?
07-03-2006, 11:12 AM
#13
1.5 BAR
Join Date: Mar 2006
Posts: 835
Re: n/a cams working against turbo setup???
Originally Posted by Joseph Davis
In a turbo setup with high turbine pressure? Typically 2:1 pressure ratio, unless the engine/setup is really efficient? You sure you don't want to think rethink that?
07-03-2006, 11:58 AM
#14
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Join Date: May 2005
Posts: 151
Re: n/a cams working against turbo setup???
Originally Posted by Joseph Davis
What a load of crap. Overlap is desireable for high revving small displacement turbo engines, period. Compare intake to exhaust pressure sometime... it's blowers that don't like overlap. :1
To the original poster: You are running a ****** 7 psi. It is impossibly to make any worthwhile amount of power from a B16 off of a ****** 7 psi, regardless of how many millions of dollars you spend on camshafts. Turn the boost up, rev to 9K, and prepare to be very happy with your NA cams in the 350+ whp range.
To the original poster: You are running a ****** 7 psi. It is impossibly to make any worthwhile amount of power from a B16 off of a ****** 7 psi, regardless of how many millions of dollars you spend on camshafts. Turn the boost up, rev to 9K, and prepare to be very happy with your NA cams in the 350+ whp range.
In fact, here is what Corky Bell says about the topic.
Pg 163
Camshafts:
Make no mistake in the fact that turbo performance cams are very different from atmospheric performance cams. The characteristics of long duration and high overlap for atom cams are unwelcome in a turbo system. The street turbo, which is generally small, operates with exhaust manifold pressure somewhat higher than intake boost pressure. This situation, when presented with long-duration high-overlap cams, creates a huge amount of reversion. Thus, the “turbo cam” tends to become a low-duration, very limited overlap cam.
RULE: Its hard to find a turbo cam that works better than the stock item.
Camshafts:
Make no mistake in the fact that turbo performance cams are very different from atmospheric performance cams. The characteristics of long duration and high overlap for atom cams are unwelcome in a turbo system. The street turbo, which is generally small, operates with exhaust manifold pressure somewhat higher than intake boost pressure. This situation, when presented with long-duration high-overlap cams, creates a huge amount of reversion. Thus, the “turbo cam” tends to become a low-duration, very limited overlap cam.
RULE: Its hard to find a turbo cam that works better than the stock item.
07-03-2006, 12:42 PM
#16
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Join Date: Dec 2002
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Re: n/a cams working against turbo setup???
Originally Posted by egVTI
so you think i should give the skunk2 turbo cams a go?
07-03-2006, 01:08 PM
#17
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Join Date: Feb 2003
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Re: n/a cams working against turbo setup???
Correct, reversion != blowtrhough.
And, when you get a setup that is mucho bukkake'd so that intake pressure starts to exceed exhaust pressure, damn if the engines don't like overlap again. Blowing a little intake charge out the exhaust valve is a good thing... anyone care to guess why?
BBKA, the only turbo cams I've ever dealt with are Speedy's Web billets for LS, and Rocket M21/M20 combo... the Webs were night and day difference, whereas the Rockets like less fuel below 7500 and 5-6% more fuel 7500-9500 !
And, when you get a setup that is mucho bukkake'd so that intake pressure starts to exceed exhaust pressure, damn if the engines don't like overlap again. Blowing a little intake charge out the exhaust valve is a good thing... anyone care to guess why?
BBKA, the only turbo cams I've ever dealt with are Speedy's Web billets for LS, and Rocket M21/M20 combo... the Webs were night and day difference, whereas the Rockets like less fuel below 7500 and 5-6% more fuel 7500-9500 !
07-03-2006, 05:06 PM
#19
3.0 BAR
Join Date: Jul 2004
Posts: 2,255
Re: n/a cams working against turbo setup???
Not that you guys are probably talking single cams or anything
But Im running a Delta 272 regrind in the built A6 and theres quite a noticeable difference in where the powerband sits and when the torque is felt over the stock si cam i was running. Idles like a ---- though
But Im running a Delta 272 regrind in the built A6 and theres quite a noticeable difference in where the powerband sits and when the torque is felt over the stock si cam i was running. Idles like a ---- though
07-06-2006, 03:24 PM
#20
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Join Date: Jul 2006
Posts: 3
Re: n/a cams working against turbo setup???
Originally Posted by Joseph Davis
Correct, reversion != blowtrhough.
And, when you get a setup that is mucho bukkake'd so that intake pressure starts to exceed exhaust pressure, damn if the engines don't like overlap again. Blowing a little intake charge out the exhaust valve is a good thing... anyone care to guess why?
BBKA, the only turbo cams I've ever dealt with are Speedy's Web billets for LS, and Rocket M21/M20 combo... the Webs were night and day difference, whereas the Rockets like less fuel below 7500 and 5-6% more fuel 7500-9500 !
And, when you get a setup that is mucho bukkake'd so that intake pressure starts to exceed exhaust pressure, damn if the engines don't like overlap again. Blowing a little intake charge out the exhaust valve is a good thing... anyone care to guess why?
BBKA, the only turbo cams I've ever dealt with are Speedy's Web billets for LS, and Rocket M21/M20 combo... the Webs were night and day difference, whereas the Rockets like less fuel below 7500 and 5-6% more fuel 7500-9500 !
