Manifold vaccuum, EGR & long duration cams

[Tony Bryant]

> Date:          Fri, 31 Jan 1997 12:15:01 -0800 (PST)
> From:          James Weiler <james at brc.ubc.ca>
> To:            Tony Bryant <Tony.Bryant at psc.fp.co.nz>
> Subject:       Re: Manifold vaccuum, EGR & long duration cams

> 
> 
> Hi Tony.  I don't have any experience but from what I've read MAP and MAF 
> systems have a problem when there is low vacume (below about 15 inches).  
> From what I understand there are significant reversion waves that really 
> confuse MAP's and MAF's.  Did the MAP system work with the other throttle 
> bodies?  These where some old Webers I understand? I'm wondering if the 
> plenum is causing some problems.  I know nothing about fluid dynamics so 
> I couldn't even begin to understand how to design a proper plenum.  How 
> did you decide on your design?
> 
> Also I've heard that alot of race cars with square cams run TPS/RPM 
> systems and they work great.  Mind you they probably don't spend too much 
> time at idle.
> 
> Not alot of help there was I?
> good luck jw 

I never tried the MAP system on the DCOE setup. The MAP reading was 
so wild, it wouldn't have been usuable even with filtering. Thats why 
I built the plenum chamber. The plenum chamber is large (6 litres), 
so it is effectively just "local atmosphere" for the runners.