e30 throttle body mods

["JASON R MCCOWAN" <JMCCOWAN@xxxxxxxxxxx>]

> Date: Tue, 30 May 2000 14:12:55 -0500
> From: "Fadeev, Alex" <Alex.Fadeev@domain.elided>
> Subject: RE: Big bore throttle body on M20 - no gain?
>
> "Apfelthaler, Horst" <Horst.Apfelthaler@domain.elided> wrote:
> >
> > I've a question to the engine gurus:
> > Some weeks ago I installed a big bore throttle body on my 2.7i
> > engine (2.7eta bottom end, i head, i harness, i ecu, i cam)
> > which resulted in 180+ hp at 6000rpm.
>
> Don't forget to chip that thing!
> 2.5L engine with Jim C chip will dyno at 177hp with peak HP gain on 15hp @
> 5000rpm (http://www.turnermotorsport.com/catalog/catalog.htm).
>
> > I had it dynoed before and after the installation of the throttle
> > body (+3.5mm in diameter) but could not see any gain in hp nor
> > in torque. What's wrong here?
>
> Nothing.
> Big bore throttle body is a voluntary weight penalty.
>
> > Is the AFM restricting the airflow too much?
>
> Nope, it is just measuring the amount of air flowing through the intake.
It
> does not matter how big the throttle body is at anything other then WOT.
If
> I remember correctly, Jim C's re-programming actually leans out the
mixture
> at high RPMs. So even at WOT with the stock throttle there is plenty of
air
> flow.
> If you want to learn more, search the digest archives
> (http://www.eskimo.com/~dalus/search.html) or get in touch with Jim C
> (http://www.bonnevillemotorwerks.com/).
>
> > Is it possible to install a bigger afm (from a big six)
> > and have a modified chip?
>
> Sure, but why?
> What you really want to do is return the waste-of-money big throttle body
> and get your money back. However, I remember reading that the people who
> sell those things never accept the returns. I wonder why ;-)
>
> alex

Alex,

you are speaking about a stock motor, right?  i've got an '88 325iS w/ a
Korman stage II comp. head, 288 cam, long-tube headers and a tri-flo
exhaust.  the car still has a BONE STOCK intake (ok, i had a cone filter kit
on it that i took off a while ago after hearing about how horribly K&N's
flowed).  the only thing i can think of that is wrong w/ the car is that
it's got that stock intake on it.  another local e30 guy (Kyle) took me out
in his modded 325iS that had similar mods as mine as far as the head went,
but he had a big-bore throttle body, big-ass cone filter, and a port-matched
intake manifold.  oh yea, he didn't even have headers on it at that time,
but the thing felt a lot more responsive than mine, and seemed to pull just
as hard.  when my car had stock manifolds, it ran like complete crap and was
slower than my mother's bone stock '91 325isA, even though i had the korman
head.  the only thing i can attribute his greater amount of power to is the
intake mods.  oh yea, he had a custom autothority chip that i tried in my
car on the same day; his still felt better.

- -jason mccowan  <<crazy modded e30 that would be lucky to run 15's.
ncc

------------------------------