The complete automotive resource for buyers, sellers, and owners like you.
Car, Truck and SUV Forums at Roadfly
+ Bentley Forums
+ BMW Forums
+ Cadillac Forums
+ Chevrolet Forums
+ Ferrari Forums
+ Jaguar Forums
+ Lamborghini Forums
+ Lotus Forums
+ Mercedes-Benz Forums
+ Maserati Forums
+ MINI Forums
+ Porsche Forums
+ General Discussion
+ Marketplace Forums
Questions Questions... (archive)

[ Follow Ups ] [ Z3 Message Board ] [ Msg. Board FAQ ]

Posted by Karl Seeger on February 10, 2000 at 11:42:03:

In Reply to: Without exception..... posted by bmv on February 10, 2000 at 10:44:28:

Boy you ask a lot of questions!

Originally I had the car tested with an extra O2 sensor put in the exhaust system (near the primary). I only did this when I was on the dyno with the variable rate pressure regulator. At the "top end" I was getting 12.6 to 1. This was a "safe" value so I did not worry too much about fuel when it was at +6000 rpm.

I just removed the variable rate pressure regulator and replaced it with a SplitSecond ARC-2 unit. This unit gives me the ability to change my A/F ratio on the fly. I also added larger injectors and an oversized throttle body.

Right now I am using a third (yes I have three O2 sensors) O2 sensor to monitor my A/F ratio. It is an inch from my primary O2 sensor (the one the DME uses). I have the gauge right on my steering column that gives me the values as differing LED lights lit. I need this meter to adjust the ARC-2.

With the level of boost I am running I believe the knock sensors are backing off my timing. To prove this I need someone to ride with me and monitor my laptop (OBD TOOL) while I drive as an "excessive" rate of speed. Last time my wife helped me with testing I scared the #&!! out of her and she will never volunteer again for THAT duty.

My plan is to get the car on a dyno and do my tests there. I plan on running pump fuel, octane booster then 95 octane racing fuel and compare the results. Based on these findings is how I will handle it.

Pump fuel is OK on the street. On the track I can feel the car "hitting a wall" and I believe it is octane related. Just putting in some STP Octane Booster made a big difference at the track so I feel I'm close. The dyno will be the final word.


Follow Ups:

[ Follow Ups ] [ Z3 Message Board ] [ Msg. Board FAQ ]
Questions, comments, or problems, please visit the Roadfly help desk. Logo © 1997 - 2018 Jump Internet Inc. All rights reserved.