Posted by Cliff Robb on August 27, 1998 at 10:51:04:
In Reply to: Re: bigger engine with e12 injection/ECU perf. mods. posted by Peter Florance on August 27, 1998 at 07:29:04:
The rising rate regulator is a nifty piece. It is a fairly standard item for the aftermarket turbo tuners. Basically it varies the pressure from stock at idle to whatever you adjust it to for WOT. Since the O2 sensor is not functioning at idle or WOT, this is when you need the adjustment on a modified engine. At part throttle, the O2 sensor compensates for the variances in stock pressure (to a point). This part is not to be confused with the much less sofisticated "adjustable" regulator. The adjustable part will only run at a single pressure that you set it at. This would probably be acceptable for a track car, but not on the street. The turbo guru Corkey Bell has done many acclaimed custom systems using a rising rate regulator. I think he may have even invented the part. Take a look at the attached sites if you want more info.
-Cliff
http://www.tristero.com/sa/business/bell/index.html
http://www.turbomagazine.com/
http://www.turboneticsinc.com/
: : Frank-
: : What is you opinion about using the U.S 528i ECU w/O2 sensor on a 3.5L(either Euro or U.S.-I don't think it should matter)? If the injectors have enough duty cycle available, I would think the O2 sensor would keep the mixture right. The O2 sensor is not involved at WOT anyway. I guess if it leaned out at high rev./WOT, a rising rate fuel pressure regulator could fix it. What do you think?
: : -Cliff
: This might be my issue also (US 3.5l in 528i euro). My WOT mixture was lean. I went to 3.0 bar conventional felt like idle was really rich. My ECU doesn't have O2 sensor!
: How does rising rate work (I mean what does it do)?
: Peter