Re: cam upgrade for 85' 4ksq

["Bruce Bell" <bbell04@ibm.net>]

I only reported my experience. I tested, put the cam on then tested again
and finally the exhaust and tested again. The cam worked very well with the
factory 4Kq exhaust. The 2.5" exhaust did improve power but not as
significantly as the cam at high rpm. In fact the exhaust with a turbo
muffler actually hurt performance at some rpms. I agree 5000 rpm up was
improved.  One possible explanation for our different experiences may be
the 5300'  altitude where I live. Volumetric efficiency is already
handicapped here and reducing back pressure seems make it worse. On a low
altitude drive in Texas last year I did notice more improvement in
performance than could be explained by altitude alone. 

Yes the manifold accounts for the biggest difference; but the CGT cat and
pipes are also smaller than the 4Kq.

Results of my testing prior to 2.5" exhaust. Numbers with the exhaust are
at the office. I can post them later if anyone is interested.

Vehicle Weight    3004
Gear Tested in:      3
Mph per 1000 rpm:11.73
Elevation 5300'

            StockSchrikStock Schrick   Stock Schrick
RPM Range   Time Time  HP  HP  Rpm TorqueTorque
1000 to 1500 1.90 2.22 16.6  14.2 1250 69.7 59.6
1500 to 2000 1.74 1.95 25.4  22.6 1750 76.1 67.9
2000 to 2500 1.70 1.83 33.4  31.0 2250 77.9 72.3
2500 to 3000 1.67 1.72 41.5  40.3 2750 79.3 77.0
3000 to 3500 1.67 1.67 49.1  49.1 3250 79.3 79.3
3500 to 4000 1.67 1.67 56.6  56.6 3750 79.3 79.3
4000 to 4500 1.67 1.65 64.2  64.9 4250 79.3 80.2
4500 to 5000 1.71 1.65 70.0  72.6 4750 77.4 80.2
5000 to 5500 1.79 1.66 73.9  79.7 5250 73.9 79.7
5500 to 6000 2.25 1.71 64.4  84.8 5750 58.8 77.4
6000 to 6500 3.42 2.00 46.1  78.8 6250 38.7 66.2

Bruce Bell
'87 4Kcsq Schrick, Ur-q exhaust & Coil Over - AAN waiting in the wings

----------
> From: PAT MARTIN <MARDKINS@classic.msn.com>

> I would disagree with this.  I put the 2 1/2" system on my car and it
really 
> helped.  Big power gain up top and no loss at the bottom.  Better yet the

> throttle response was much better.
> The coupe vs 4kq difference is the manifold more than anything.
> 
> Pat Martin
> 864000csq turbo, 2 1/2 cat back, H&R-Boge, MC and loving it.  Drilled
rotors 
> stopping it. Koenig Cobra 16x7 with Yokohama A520's turning it,  K&N and 
> uh....  
> 95 subaru legacy 
> Bothell, Wa
> 
> 
> I would not do the exhaust unless yours is ready for replacement anyway.
> Unlike the Coupe GT, the 4K quattro has the best exhaust system Audi put
on
> a normally aspirated motor.  This exhaust is worth 5 hp over the Coupe
GT. 
> 
> I use the Schrick 272 cam in my 4kq. with the factory exhaust in place
the
> car picked up about 10-12 hp at the top end. You won't notice the
> improvement though unless you push the motor to the 4000- 6000 rpm range.
> Below 3000 rpm there will be slightly less power. Remember a cam doesn't
> make horsepower, it is a tool for adjusting the torque curve of a motor
to
> your driving style and needs.  
> 
> Bruce