re. Cam questions on turbo and N/A
Swann, Benjamin R. (BSWANN)
BSWANN at arinc.com
Tue Oct 2 10:09:54 EDT 2001
Of all the silly things I've heard....
So a few people suggest that the turbo cam in an N/A car will give a slight
increase in power, especially on the top end. Huw tried it if I remember
right and he said he felt some gain.
The thing that is making me wonder though, someone told me that replacing
the MC cam with one from a JT (N/A 4kq) gave them more power in their turbo
engine. So the turbo cam gives more power in the N/A cars, and the N/A cam
gives more power in the turbo engine? HA why didn't Audi just install them
like that at the factory!?
I'm still not sure about the N/A cam in the turbo engine (seems the overlap
would be wrong, but what do I know), which is why I ask here. Anybody have
I've heard the turbo cam as being the hot tip, but a side to side comparison
with the NG cam showed very little difference - NG being a tad bit more
aggressive. The NG cam may provide some help for the lower compression 2.2l
engines, so therefore the turbo might as well(but I doubt it).
Without going into the details of duration and lift, I can understand why
the NG cam would work as an upgrade, albiet small one in one of the earlier
2.2l N/A hydraulic lifter engines. I wouldn't think it would be very
noticable, except that the swap may be putting in a cam with less wear and
new lifters - all combined to make some noticable difference. The 2.3l NG
cam is a tad bit more aggressive than a stock 2.2l JT cam - a little more
lift and duration - I forget the exact numbers.
I would not see the N/A cam doing that much good in a turbo car, except that
there may be a bit more flow on top end. I would think drivability suffers,
as the cam is made to provide a smooth idle and low end torque, and
agressive grind is not necessary because of the turbo. Drivability is the
reason for the conservative design of the stock turbo cam. I understand
that a special assymetrical grind can be made to assist the turbo engine
intake while keeping the exhaust closer to stock which is necessary for
velocity and keeping the exhaust from closing too late and defeating the
earlier intake opening.
Elgin can provide more details of the grind specifics that would be
appropriate for the car relative to displacement, stroke, bore, loading/type
of driving, N/A or turbo, exhaust mods, intake mods, etc.
Sillyness - perhaps.
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