Oxygen sensor
 

I have a 1998 Boxster setup for BSR. I have been running it with no oxygen sensors. I can't see any reason to use them since there is know cats. Anyone have a comment?

Yes, you want the front two in place because they control fuel and mixture trims. The car will run like poo without them. The two in the rear you can tie off up out of the way because they are for emissions only.

Thanks I was told to tie off the front use the rear, thanks for your help.

The O2 sensors provide feedback to the ECU which continually adjusts the mixture to balance performance and emissions. If you don't have the O2's hooked up, then the ECU runs in "open loop" mode with the stock mixture maps and can't adjust the mixture for performance or emissions.

In my Spec Boxster, I have the Fabspeed cat delete pipes which have a mount for the O2 sensors but still delete the cat's.

Thanks I also have the fab speed exhaust.

Pleasure to meet you :) (Spencer called me about your car) :cheers:

Got it on the track after O2 in and ran very well. Now I have to get use to the car after 6 years racing with the 944!http://986forum.com/forums/uploads01...1407590937.jpg

You'll be fine. I took a multi time 944Spec champ and put him in a BoxsterSpec. He promptly won a championship in BoxsterSpec :)

These cars move a lot under braking.. rear wheel steering, so be aware of that. :cheers:

and.. you will end up running the car square :) I see it's narrow front right now. Your 944 was square, the Boxster is also.

The fast east coast guys are all square, the fast TX guys? square, the fast west coast guys? square. :cheers:

Where is this rear steering effect coming from? If these cars are fitted with the urethane bushings or spherical ends on the suspension pieces and your set up is right whats happing? Bump steer, roll steer, chassis flex?

I cant tell you that :)

I will say it's more pronounced the larger/wider/stickier tire you use.

Porsche changed a few of the rear suspension pieces multiple times from 97-2012.

I know why :)

I gave you just enough information to go on. I was blown away when I learned about it. It took mounting strain gauges on multiple suspension components. The results? Crazy. The fix? easy :)

If braking causes this, then cornering forces must do something similar.

Just for the record I've never raced a Boxster and haven't competed since the early 90's and that was in SCCA class of Sports 2000. This just brings out the racer curiosity in me is all.

We utilized a data logging strain gauge. We initially tested with it mounted to a anti roll bar drop link to test the effective rate. You turn on the logger and run the car around :) come back and download the info and dump it into Excel for a nice plot :)

I'll see you TX and some time and let you know what we found. It's very interesting, and only the really pro race guys have it figured it. Only the guys who know to use strain gauges to test :)

If I use stock 8.5 x 17" rims with 255/40-17 all around do I need front spacers?

No spacer needed. In fact you may rub the outer of the tire on the fender lip with a spacer.

It all depends on the tire, some run wide. I have most recently run a 245/40-17 Hoosier R7 on an 8.5" et 50 on the front. No spacer, no rubbing.