Info on "cutting the base circle" (CAMS)
03-07-2008 | 09:53 PM
#48
Drifting
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From: Bountiful, Utah
Yes Jim, I know...we have had them do cams for us for years. Just got an e-mail from Dema a couple of minutes ago giving me the status of our sets. This will be the first base grind S3 set I will be installing in an otherwise stock S4 and I will be dyno'ing it.
03-07-2008 | 10:49 PM
#50
Under the Lift
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From: Buckeye, AZ
I played courier today to get a bunch of 928 cams from the nitrider to Dema. Dennis's are in the batch, and we want to finish the rebuild. I assume yours were in there as the batch was large (I couldn't lift the box). Shouldn't be much longer.
03-08-2008 | 02:40 AM
#53
Drifting
Joined: May 2002
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From: New Zealand
brendan, i seem to recall mark k posting that information in a thread where he was talking about adapting the S3 cams to fit his engine.
looking at the numbers it looks like the elgin profile might be a better balance between intake and exhaust than my current setup. the extra lift on the intake cant hurt either
looking at the numbers it looks like the elgin profile might be a better balance between intake and exhaust than my current setup. the extra lift on the intake cant hurt either
03-12-2008 | 05:26 PM
#56
Drifting
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From: New Zealand
any predictions for how much the elgin cam will outperform a GT cam by?? im trying to asses how much if any i stand to gain going from my 'piper' cam to the elgin grind. perhaps my piper exhaust cam has too much duration. im seeing about 380 bhp with this cam in a GTS engine - not far away from the dyno on louis otts web page for the GTS / GT and i have the same exhaust configuration.
03-12-2008 | 05:32 PM
#57
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I should get modified S3 and fixed GT cam sets on Monday. S3 has 0.5mm taken off from base circle and GT had quite severe pitting fixed. Grinder said 0.5mm difference makes S3 cams open and close 10 degrees earlier and later than stock. So duration increase is 20 degrees. GT cams should be same as before as only little was taken off from base circle to counter lobe tip machining.
03-12-2008 | 06:25 PM
#58
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If I understand correctly 10 degrees increase on both sides in S3 cams results these degrees.
How good or bad this is? Will MAF work with these numbers?
Code:
S3 S4 GT GTS S3 +10°/+10° 11° after TDC 11° after TDC 3° after TDC 13° after TDC 1° after TDC 50° after BDC 36° after BDC 42° after BDC 61° after BDC 60° after BDC 30° before BDC 17° before BDC 30° before BDC 28° before BDC 40° before BDC 5° before TDC 2° before TDC 5° before TDC 12° before TDC 5° after TDC
03-12-2008 | 08:49 PM
#59
Drifting
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From: New Zealand
erkka, where does that info come from? im trying to reconcile the GTS figures with the measurements that were taken of my GTS cams - in particular the exhaust which measured 240 degrees duration - longer than the GT exhaust??
03-12-2008 | 09:49 PM
#60
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From: saratoga, ca
this looks interesting. longer duration should be better and the .5mm more lift cant hurt as well.
Has anyone done a base circle grind without the lash caps, assuming that the hydrolic lifter can adjust to the .5mm greater distance to meet the base circle?
mk
Has anyone done a base circle grind without the lash caps, assuming that the hydrolic lifter can adjust to the .5mm greater distance to meet the base circle?
mk
If I understand correctly 10 degrees increase on both sides in S3 cams results these degrees.
How good or bad this is? Will MAF work with these numbers?
Code:
S3 S4 GT GTS S3 +10°/+10° 11° after TDC 11° after TDC 3° after TDC 13° after TDC 1° after TDC 50° after BDC 36° after BDC 42° after BDC 61° after BDC 60° after BDC 30° before BDC 17° before BDC 30° before BDC 28° before BDC 40° before BDC 5° before TDC 2° before TDC 5° before TDC 12° before TDC 5° after TDC