daltvater

Trying to install Cat Bypasses I bought new from Fabspeed. There is a hole on each Bypass pipe for an O2 sensor. Bought new and specified that I need the 95 version. I thought their was only 1 O2 for a 95. Am I just supposed to plug one of the 2 holes and if so which hole? Anyone experience this?

Thanks!

Dan

Bill Verburg

One side should be plugged, doesn't matter which. Why not call, see if they erred or if you are supposed to supply the plug

glennp_993

I'm seriously considering installing the same bypass pipes on my '96. i would appreciate any helpful hints or pictures you might have. Thanks, Glenn

NP993

If necessary, you can buy an 02 sensor bung from a muffler shop for just a few bucks...

993inNC

If it matters, those tend to be steel. Either see if a stainless plug can be ordered or go get a stainless bolt and use that instead, otherwise the steel plug will rust in place.

NP993

That's a good point. If you do go with steel, install it with plenty of hi-temp anti-seize, the copper stuff. On my previous 911, I installed an 02 sensor bung so that I could tune the car with an LM-1 (I was running Megasquirt EFI). Never had a problem with rust, given the anti-seize.

slvr993

I know this is an old thread............

So it doesn't matter which bank the sensor reads from? With fabspeed the pipes don't cross over so you'll be reading only from one bank or the other. That sounds dangerous to me. Is it?

Jeff

Bill Verburg

No, it's normal to read only 1 bank, both my cars are set up that way, 1 w/ stock 993 manifolds/Fabspeed bypass & 1 w/ headers. No problem.

Just for kicks I check w/ an LM wideband ocassionally but it does'nt matter which side is sampled

Gasser

Sorry to hijack a littel but its on topic...

I have these on my 993 race car with the Fabspeed supercup exhaust pipes. Seems like a lot of piping under there and Im wanting to get some more weight off the back of the car.
My question is, do you guys think there is a horsepower advantage for the longer pipes rather than just making some straight pipes out the back of the bumper? The stock headders point to the center of the rear bumper so building two short stainless pipes to exit out the center ALA GT3 would be 15 to 20 pounds lighter and easy to do.

Any dis-advantage? They don't cross over now as an X pipe so they really are just very long straight pipes with a very small muffler on the back, if you want to call it that.

???

Jeff

Bill Verburg

You'll make a lot of noise!, I'd check f/a ratios, you will probably want a new chip(unless you have Motec then yo just need to recalibrate)

I like the idea of loosing another 16-20#s from the extremes, but there are fewer venues w/o noise restrictions every year

Speedyellow993

I have a set kicking around. Anyone else need a used set for Bischoff brand muffler fitment? A very noticeable power difference. In very good condition. They also shave alot of weight off the back end.

My set came with the second O2 sensor hole plugged. No CEL ever on my 1995 C2.

If you are planning to do this make sure you buy 6 new bolts before you start.

Gasser

Funny, my buddies RSA with straight pipes is not as loiud as my catless supercup exhaust. Most love the way my car sounds and its loud as hell. I already have a chip that came with the car. Im just interested in getting the weight off. I just can't imagine how taking a long open single pipe exhaust and making it 4 feet shorter on each side will change the A/F ratio that much although a good dyno would be a great Idea after a change just to see what effect a good set of headders and short pipes did. Motec, now thats another thing all together. One of these days Ill be there but not yet...$$$

Thanks for your reply. Ill do some more research...

Jeff

Bill Verburg

A LM1 or 2 recording wideband is a great way to check on this stuff, better to know than guess

hard to believe that an open exhaust is quieter than a poorly muffled one

craig001

Hey Speedyellow,

I might be interested in adding your bypass pipes to my collection of uninstalled parts in my garage, LOL. Does having these on make the car louder? My wife all ready does not like the car from hell's sound level. She thinks it is too loud as is - factory motorsound package on car.

Thanks.

mhm993

Craig,
Happy wife = no cat bypass, and never supercups. If your marriage can endure just a little more noise, try maxflows or the rsr's. Bypass will have you sleeping on the couch.

Except my wife--her little race car is louder than my track car.