Thanks Trev, I have 36 mm chokes in my webers at the moment and I figured
out the crossectional area(combined) to be 40.71cm^2 on my 2L motor and its
not too doughy down low at all. With the RB30 throttle body the entire
cross-sectional area is 23.75 cm^2 which means on a 1.8L litre it should go
pretty well and have plenty of low end torque compared to the setup on the
2L. Thanks for the advice
Daniel Kroehn
Recommending Datrats, supplying quality Datsun performance parts
www.Datrats.com.au
----- Original Message -----
From: Pooley, Trevor <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, June 28, 2001 1:02 PM
Subject: RE: Throttle Body size??????
> Daniel,
>
> You should be able to work it out theroetically.
>
> I haven't done the maths yet but will have to investigate. Should be
easier
> to work out for a NA motor than a boosted intake but simular principals
> should apply. Think about main venturi's in DCOE weber's Small ones
increase
> air speed at low revs (ie throttle response) but at the expense of
outright
> flow at higher revs (hence their common description of Chokes).
>
> Have look at some racing cars F2/3. They have a small resticter in front
of
> a massive plenum (Which must stuff up flow at higher engine speeds). The
> outright rally cars have a restricter and only make 10hp or so more the
> Group N.
>
> OK so what is the reverse of all this. Poor low rev throttle response.
Also
> why go big if there is a restriction in other areas. Ports, valves,
> intercooler, intake plumming also consider manifold length, diameter and
> plenum size etc.
>
> Bottom line is everything must work together and going too big with the
> thottle body may make it undriveable at low revs. It may make the system
> mismatched in other areas making the whole thing worse.
>
> Regards
> Trev
>
>
>
> -----Original Message-----
> From: Daniel Kroehn [mailto:[EMAIL PROTECTED]]
> Sent: Thursday, 28 June 2001 10:34
> To: [EMAIL PROTECTED]
> Subject: Re: Throttle Body size??????
>
>
> Just wondering Trev, how you go about figuring something like that out?
Any
> simple equations to do so or is it more about an experienced guess?
>
> Daniel Kroehn
> Recommending Datrats, supplying quality Datsun performance parts
> www.Datrats.com.au
>
> ----- Original Message -----
> From: Pooley, Trevor <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Thursday, June 28, 2001 9:54 AM
> Subject: RE: Throttle Body size??????
>
>
> > Steve,
> >
> > I would be looking at how many CFM your engine needs at that boost
level.
> > Then I would find out what T/B size suits.
> >
> > Regards
> > Trev
> >
> > -----Original Message-----
> > From: steve taylor [mailto:[EMAIL PROTECTED]]
> > Sent: Wednesday, 27 June 2001 5:40
> > To: ozdat
> > Subject: Throttle Body size??????
> >
> >
> > Hey everyone,
> > Im about to replace the restrictive stocky z18et throttle body. My
> > question is what size t/b do you guys think would be appropriate?? Im
> > currently running a standard fj20 T3 turbo at around 15-17psi?!?! I have
> > been able to get my hand on a standard 55mm fj20 t/b (thanks matt) do
> > you think this will be big enough or do you think i am better off going
> > for something bigger like the 65mm ford ones??? In the future will
> > prolly be investing in a T3/T4 turbo in the hunt for more power.
> > Any thoughts
> > Steve.
> >
> >
>
>
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