Originally posted by urq20v
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Cams 7A inlet and exhaust RR results
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Its no secret, Dougs car has changed massively since this. The best setup that i have tried in my car was 7A exhaust and stock 3b inlet.
7A intake cam reduces torque and creates more lag, with a minimal increase in power. I have tried both 7a and 3b intake cams. I have no dyno figures, but the 3b intake cam was better for everyday driving, and gave 400rpm less lag than 7asigpic
Tom C - www.rcmr.co.uk
Audi UR Quattro
Audi 100 C3 2.0 5 cyl 115ps
Audi S2 - 07k engine project aiming for 800ps
Audi B5 RS4 645ps 911nm
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Originally posted by audiman View PostIts no secret, Dougs car has changed massively since this. The best setup that i have tried in my car was 7A exhaust and stock 3b inlet.
7A intake cam reduces torque and creates more lag, with a minimal increase in power. I have tried both 7a and 3b intake cams. I have no dyno figures, but the 3b intake cam was better for everyday driving, and gave 400rpm less lag than 7a
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We can all think. Do you have proof that this is possible??sigpic
Tom C - www.rcmr.co.uk
Audi UR Quattro
Audi 100 C3 2.0 5 cyl 115ps
Audi S2 - 07k engine project aiming for 800ps
Audi B5 RS4 645ps 911nm
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Just my ramblings:-
Both 7A cams:-
The power loss is could be due to the exhaust cam being too long duration and the charge blowing through the cylinder at lower revs, hence the increase in lag and loss of low end torque. Using the world of normally aspirated engines as a guide a shorter duration exhaust or an exhaust timed to close earlier would allow for better low end performance than with both 7A cams. Top end performance would be reduced. A longer duration inlet is not a bad thing, it just has to be matched to the exhaust. Catcams use this theory in their turbo cams but to get more flow they give much more lift on the exhaust.
3B/ABY inlet + 7A exhaust:-
This prevents a loss of midrange power as the inlet opens later and so there is less blow-by as the overlap is less.
However, there is also the issue of the turbine and EM restricting flow so you can only take the exhaust cam so far before any further increase in duration becomes pointless or even has a negative effect if the exhaust gasses flow back into the cylinder.Last edited by Rusty; 20 February 2008, 16:05.Cheers'en, AndyC
1994 ABY Coupe - Projekt Alpinweiss
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its fine, same part numbers in fact. will rev to 7800 without problemssigpic
Tom C - www.rcmr.co.uk
Audi UR Quattro
Audi 100 C3 2.0 5 cyl 115ps
Audi S2 - 07k engine project aiming for 800ps
Audi B5 RS4 645ps 911nm
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