re: multi throttle

[tedcrum@xxxxxxxxxxxxxxxxxxxxx]

My experience is from the Motorcycle side of the house.

With a single AFM (MAF or otherwise) and multi throttles, the mixture 
strength is wholly dependent on throttle sync: The AFM sets a single fuel 
delivery for all six injectors, which works well when all cylinders are 
controlled by the same throttle. But if all cylinders get the same fueling 
and there is a 10 percent variation in airflow between throttles, there 
will be the same percentage variation in mixture strength.

I believe that this is the reason that the multis never came here (smog).  
This effect can also lead to surging in O2 sensor engine where the rich
cylinders steal fuel from the lean ones as the sensor maintains the
average mixture.

- -tc


> Date: Sun, 30 Mar 2003 21:50:55 EST 
> From: CLordan150@domain.elided 
>
Subject: Multi throttle intake recommendation 
> 
> Gruppe: 
> One of the well-known parts/accessory vendors lists a multi-throttle 
> intake for various engines among their offered wares, similar to, for 
> example, the setup on the E30 M3 and the E28 M5. The offered parts are for 
> the M42/M44, M50 series, etc. 

> Given the rather high asking price, I'm asking if any of you have 
> experience with these systems. Any advice regarding ease of  
> installation, measured performance gain or loss, fuel economy changes, 
> or any other comparison would be appreciated. 
> 
> TIA, 
> 
>Chris Lordan

- -- 
Ted Crum
1988 735i 5-speed
1988 K75c
tedcrum@domain.elided

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