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Re: Turbo Fuel Cut Defensers

To: "'autox'" <autox@autox.team.net>
Subject: Re: Turbo Fuel Cut Defensers
From: "Burns, James B." <BurnsJB1@central.SSD.JHUAPL.edu>
Date: Sat, 13 Feb 1999 09:44:11 -0500
David Hawkings wrote:
>>
>>David Hawkins
>>93 MR2T rendered totally helpless in ASP by the FCD rule (fuel cut at
>>12psi)
>>

What David is alluding to here is that on the MR2 Turbo, fuel cut happens
somewhere around 12-12.5 psi.  The stock boost spec is 7.3 - 11.8 psi.  If a
particular MR2T runs near the high end of the boost spec in stock form, then
SP legal mods such as a free flowing intake and exhaust can easily cause
boost to rise slightly and hit fuel cut.  Therefore, an MR2T prepped for SP
has to keep the engine pretty much stock.  A 200hp 2800 lb. car with turbo
lag is going to be embarrassed in ASP.

In the case of my MR2T (A-stock), my boost peaks around 11-11.5 psi which is
near the high end of the spec.  Per the shop manual, this is measuring in
3rd gear at greater than 3000 rpm.  However, in 5th gear with a heavy load
on the engine (going up hill) and under ideal atmospheric conditions I have
managed to hit fuel cut.  And my engine and all boost control systems are
totally original stock (only 21K miles on the car).  So if I decided to move
to ASP and remove the cats and put on a free flowing intake, then I'd
probably hit fuel cut all the time.

I understand the reason for the rule against fuel cut defensers, but in my
case I feel that it is a little too restrictive since it keeps me from doing
the  intake and exhaust mods that are normally done in SP.  I guess I need
to write a letter requesting that the MR2T be moved to CSP since it has to
retain a stock engine.  Hmmm, even in CSP it probably couldn't compete with
the high power M3 or the tiny CRXes and RX3s, so maybe DSP is the right
place for it.

Brad Burns

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