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Re: Ceramic coating EM's - II
In a message dated 10/5/99 1:40:45 PM Central Daylight Time,
> > maybe concurrent exhaust mods necessary.
> Am thinking of doing that 3-inch downpipe story, but if I do then
> I guess I'd coat that as well then. So in all coat the following:
> manifold, turbine housing, downpipe and connecting flange. That'd
> see a fair amount of cash. :) Wastegate? No.
Not sure the point, but good question given my basic ones. Why do the
manifold at all? What expectations do you have? In theory, you are
increasing the exhaust velocity to the turbine, after that really isn't a
heat v velocity problem, remember a turbine is a heat generator all it's own.
In practice, coating the inside of the EM didn't do a thing for 0-60 times
measured, but I didn't expect it to. Look, the longest runner to the turbo
is maybe a foot, pretty optimal for a turbo application. A 10% increase in
power? I should been able to measure that (tested stage II fwd autobox, no
accel preload). So I'm thinking 5% or less. That's the case, even the DIY
can hardly justify the time, better mods elsewhere in the system. Where one
sees big gains in CC, is with v6/v8 turbo cars that have a huge crossover
pipe that can lose a lot of heat.
So doing it for heat to the turbo, I suppose is valid theory, IME not
measurable results. Personally, I'd save the money and put a bypass valve in
my 10vt car first.
Do it for underhood temps. Well, ok, I suppose. Given that the highest heat
under the hood is the turbo, and CC the EM moves the EM heat to the turbo,
now what? Measure the temps off the hot side of your turbo (CC'd or not),
that thing cooks. What you need, is someone with some BTDT measure on
underhood temps. If that's what you are going after, by the time you go all
the way to the cat, a more effective mod would be some hood vents, ala Sport
q, and every audi race car.
> How about using a heat dispersing coating on the outside then?
Might help, might not see anything. I tried heat dispersion coating on G60's
and rotor hubs, and found no real measureable gain with or without. Bad
> Do the downpipe then? That can be done DIY.
Look, I'm all for good mods. CC coatings have some advantages, but the
location of the turbo on an audi really makes it a minimal gain. My
experience with coatings, is that porsche has a reason for CC in their turbo
apps. But, it's not the manifold the turbo or the downpipe. IF they saw
some gains elsewhere, then I'd bet they'd use it. My own btdt tests really
show little (and no measurable) gain in the areas you guys are proposing.
CC is not bad. I just question how "great". That would depend on the
definition and the intention.
My .02 arbitraged thru the peso