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Re: turbo cam in N/A 5K
>What differences will I notice - better all around (dream on, Mike), no
>bottom end, better top end, or reverse, worse gas mileage, lumpy idle, mix
>of above?
>What I'd really like is about 150-160 HP with the same docility,
>reliability and drivability as I have now. (Yeah, I know those words are
>not usually used in conjunction with older Audi's, but believe me, you'd me
>AMAZED at the stuff some people drive, completely oblivious to all kinds of
>problems and critical safety issues!)
Based on the numbers I have seen, the camshaft in the 2.3L NG engine of
the '87.5 Coupe GT is the same (or similar enough) as the "turbo" cam used
in later-model I5 hydraulic heads.
Assuming this is the case, here is an interesting comparison:
KX/JT engine NG engine
Displacement: 2226cc 2309cc
Compression ratio: 8.5:1 10:1
Horsepower: 110/115 @ 5500rpm 130 @ 5600 rpm
Torque: 122/126 @ 2500rpm 140 @ 4000 rpm
So the difference between the two engines is ~15-20hp and 14-18lbs-ft. of
torque, and the torque peak has moved up from 2500rpm to 4000rpm. Now
consider the fact that the NG engine has greater displacement and higher
compression (along with a knock-sensing ignition). I would say that the
camshaft accounts for very little of the power difference between the
two engines. So, what does this say about the gain from putting a turbo
camshaft into the KX/JT engine? My guess is around 5hp tops, at the expense
of shifting the peak torque higher up in the rpm range. The engine will
probably pull better above 5K rpms, as well, but how useful is that,
really? For the track, probably, but for daily driving, not very.
Later,
Eric
'85 Coupe GT
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Eric J. Fluhr Email: ejfluhr@austin.ibm.com
630FP Logic/Circuit Design Phone: (512) 838-7589
IBM Microelectronics Div. Austin, TX