Re: Dragrace tweaking of 5ktq. (long)

["Bernard Littau" <bernardl@acumenassociates.com>]

Jörgen postulates:
<
I have noticed that high temperature in the engine compartment cost me up to
one second 0-60mhp! I did a few 0-60 sprints whith the Gtech a few days ago,
outside temp was 77degF.

The first run was 6.18s, the next was 6.28, the one after that 6.43 whith a
real good start! The fourth run got me an 6.61s 0-60! The runs where done
with only a minute between them and the car was already a bit hot before the
first run. One hour later in the same temp, but after driving at 50mph for a
few miles, I tried again; 6.08s with a passenger!
>

I am not very savvy in these sorts of things (yet :-) so feel free to shoot
me down, but...

It seem to me the engine compartment temperature is not your largest
contributor to your heat problem.

First off, how consistent are you with your 0-60 times with the GTech?  The
variations in your email could well be due to slight movement of the GTech
during runs.

>From your web site, you are getting consistent 0-60 times when you don't
drop the clutch, but they are slower than 7s.  Your clutch being hot may be
a factor.

The engine compartment temperature is at best a secondary factor to
performance.  What is primary is the temperature (density) of the charge
into the cylinders.  Have you any idea what the temperature of the air
entering the manifold is?  Especially from run to run?  As your turbo heats
up, you need a better way of cooling the air exiting the turbo -- you need a
better intercoolor.  I would put my money and effort into quantifying the
air temperature after the intercooler, and reducing the intercooler exit
temperature of the air as much as possible.

You are getting some awesome performance out of your Audi -- I wish mine
were as fast.

Best,

Bernard Littau
Woodinville, WA
'88 5kcstq   (0-60 around 9s on a good day :-(
'94 K11RS  (so I know what 0-60 in less than 6s feels like :-)