boost flutter?

Ingo D. Rautenberg ingo at
Tue Sep 17 18:35:52 EDT 2002


I'm not sure quite how to answer your Q (cause I don't want the
responsibility if something goes awry).  Yes, by "turning up the wick" I'm
talking about turning down the wastegate spring, which is supposed to be an
upgraded one anyways (I forget which, but it would be easy enough to check).
I'm pretty sure I had it turned down too much, so that I busted the
headgasket (but that may be not only because of this, but also because I
have the old style headgasket).  Not to the point of affecting real
drivability, as this happened over a year ago with no discernable coolant
loss and no smoking out the tailpipe either.  Some argue that with the
motronic systems, this shouldn't matter because of the wastegate frequency
valve and should only help bring on boost quicker, but I think if you have
the wastegate preloaded too much, you can up the effective boost to
detrimental levels.  I won't know until I take the head off.  Realize that
this was 25+ psi with the stock k24 turbo (a definite no-no).

Why not ask Ned Ritchie -- after all, you bought the turbo from him and he
wants you to be a happy customer.  BTW, what octane are you running?  If
it's under 93, the decrease may be a safety issue for your motor.  Once
you're much past 320 hp, costs go up exponentially, as you need to address
the connecting rods, increase fueling, RS2 MAF, high flow injectors, etc.
just as you allude to.  How much money you want to part with?  ;-)

'91 200q20v...Slightly modified
'83 Urquattro
('90 v8q RIP)

----- Original Message -----
From: <Djdawson2 at>
To: <ingo at>; <pjrose at>; <dans at>
Cc: <200q20v at>
Sent: Tuesday, September 17, 2002 4:58 PM
Subject: Re: boost flutter?

> Ingo,
> When you say "turning up the wick", do you mean additional tension applied
> the WG spring?  Are you using the stock spring?  How much do you turn this
> "wick" up?  I'm using a RS2 hybrid turbo unit I got from Ned, and using
> is supposed to be a "Stage 3+" chip set.  My understanding is that this
> maintains maximum boost levels higher in the rpm range as opposed to those
> chips that back boost off above 4k.  On extended rpm runs, I still see a
> steady decrease in max boost as the rpm climbs.  I'm wondering if I can
> see some significant performance improvements if I can somehow keep the
> from backing off, or maybe even run a higher peak boost level.  With the
> larger turbo and the RS2 EM that I'm using, I don't think I'd be at risk
> grenading... but would be interested in hearing about some BTDT before
> looking for such improvements.
>   After seeing that ur S4 on ebay with a nearly 400hp dyno chart, and
> that I'm probably 100+ short of that figure, I'm wondering where the
> of the power comes from...  ECU, injectors, cam, fuel pressure, airflow
> sensor???  Where's the best place to go for the next level of improvement?
> TIA,
> Dave

Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (
Version: 6.0.386 / Virus Database: 218 - Release Date: 9/9/2002

More information about the 200q20v mailing list