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Farzaan's Wastegate (was: Why Smaller Pulley?)

To: autox@autox.team.net
Subject: Farzaan's Wastegate (was: Why Smaller Pulley?)
From: dg50@daimlerchrysler.com
Date: Fri, 30 Apr 1999 09:31:22 -0400
Paul Foster <pfoster@gdi.net> wrote:

> DG wrote:

>> All forced induction cars have a natural limit to the amount
>> of power that can be made with the stock turbo/blower. The
>> things only flow so much air, and no matter how much
>> wizardry and voodoo you do with boost control devices, _as
>> long as the impellers and housings themselves are not modified_,
>> there is an upper limit to the amount of power a given motor
>> can make.

> Well... not according to the SEB. Due I think to Farzaan's post that you
> could get basically infinite boost by deliberately choking off the waste
> gate exhaust

Well, that's not _quite_ what Farzaan's post said.

Farzaan's post was that as the current rules allow any exhaust downstream of the
turbo, one could legally build an exhaust system with separate pipes for the
main turbine outlet and the wastegate outlet. Indeed, they're quite common in
certain circles, and I believe that some Porches come with this stock.

Now that you have a separate wastegate pipe, one could install a *second*
wastegate in series with the stock wastegate. As the farthest-downstream
wastegate "wins" one could now hang all the boost controllers they wanted to on
the second wastegate and get the full effect, while leaving the stock wastegate
and all its control devices intact.

Note that this ABSOLUTELY DOES NOT PROVIDE "INFINITE" BOOST! The turbo is still
subject to the laws of physics, and still has a flow limit, etc. All this does
is provide a "legal" means of putting a boost controller on an SP car.

If boost control devices were legal in SP, there would be no benefit at all to
doing this.

> I agree they should allow them. If they allow any engine management
> system on NA cars then fair is fair. But the SCCA has never taken a very
> fair stance with turbo cars. In fact, they outlawed them from club
> racing a number of years ago. it looks like only a matter of time before
> the same thing happens with Solo II...

I think the SEB wants to do the Right Thing here. My understanding of why that
crazy rule was proposed was because they want to have rules that are easily
enforcable in Impound - cut and dried. It takes a little bit of work to
understand turbo boost control systems, and it's not reasonable to expect every
Impound worker to be a turbo expert.

The goal of reducing complexity is worth striving for; it makes everyone's life
much easier. However, the proposed don't-touch-the-exhaust rule not only doesn't
work, it's not fair.

I've worked very hard trying to come up with something that is simple,
enforcable, and fair. My proposal seems to fit the bill, and that nobody has yet
told me otherwise I find encouraging.

Let's hope the SEB feels the same way.

DG



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