An EFI/Turbo/knocking question

Jim Green jeg1976 at
Fri May 17 12:48:58 EDT 2002

Hi Greg, I'm going to take a stab (in the dark) at
--- "Roa, Greg" <Greg.Roa at Cinergy.COM> wrote:
> Alright, I must admit Mr. Gough's continued tale
> makes me jealous.   The
> thought of having EFI and a turbo on my JT makes me
> giddy.
> I do have a question though.  In the past, Javad and
> others have said
> that the JT is ok for a low compression turbo, even
> with the stock
> compression ratio.
> Mike said that his car with the EFI and the turbo,
> is much stronger now,
> running ~6psi, than it was while running 9psi.
> Assuming that he is
> making more power, does the car become more likely
> to knock at the same
> boost level?  With the EFI, you would have more flow
> into the engine at
> the same boost level due to the elimination of the
> AFM, right?  If so,
> you would have more air and fuel entering the
> engine, and therefore, to
> the engine it is similar to running more boost,
> correct?

I don't think it's like running more boost, you're
just making it easier for the engine to breath.  Which
makes it easier to get all the bad gasses out and the
good stuff in.

> So the main question is, what, if anything, would
> allow you to make more
> power without knocking, with EFI?  Is it simply more
> accurate fueling,
> so you avoid a lean condition, and therefore
> hopefully knock as well?


> Sorry for the lengthy and complicated question.

All the stuff that you do to a normally aspirated
motor to make more power usually still applies to a
turbo motor.  Turbos are just easier to mod because
you can force the air into them if you have room to do
so.  With the JT, the compression ratio limits that so
you have to start going back to the old tricks of
improving airflow.  Somebody correct me if I'm wrong!


Jim Green
'89 90tq EFI

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