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.
>
>
--membersozdat-------------------------------------------------------
OZDAT Mailing List Please Note:-
Send (un)subscribe requests to [EMAIL PROTECTED]
Send submissions to [EMAIL PROTECTED]
No unauthorised redistribution of this email
http://www.ozdat.com/ozdatonline/index.htm
http://www.ozdat.com/ozdatonline/listindex.html
http://www.mail-archive.com/[email protected]/
---------------------------------------------------------------------
