cat bypass issues
#1
Rennlist Member
Thread Starter
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Hey gang.
I just picked up a set of cat bypass pipes for my 87 928 s4 auto.
they are in the shape of an "H".
here is the issue..
the cross over in the H is just a spacer tube..there are no openings. so basically they are straight thru pipes..there is a dummy O2 sensor hole in the cross-member...will the car run ok with no inputs from the O2 sensor?
Has anyone ever used these before?
I just picked up a set of cat bypass pipes for my 87 928 s4 auto.
they are in the shape of an "H".
here is the issue..
the cross over in the H is just a spacer tube..there are no openings. so basically they are straight thru pipes..there is a dummy O2 sensor hole in the cross-member...will the car run ok with no inputs from the O2 sensor?
Has anyone ever used these before?
![Name: hpipe1.jpg
Views: 177
Size: 80.1 KB](https://rennlist.com/forums/attachments/928-forum/508133d1296185663-cat-bypass-issues-hpipe1.jpg)
#3
Rennlist Member
Thread Starter
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
I put air in it and capped the ends..nothing came out the center port...Apparently the H and O2 port were put in to fool an emissions inspector...If I bolt it up< can I just put the O2 sensor on one side or the other?
#5
Rennlist Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
That's really pathetic. Yeah, put it in either side. You might want to consider an X-pipe, it will give you lots more power. IIRC, those H pipes were only 2" tubes which are smaller than the stock pipes.
#6
Rennlist Member
Thread Starter
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
It was given to me...I am not too worried about more power,,,I want it to see if i like the sound better, and i want to do away with the cats...I have heard a few stories about the cats getting so hot that fires have started. I will dive into the car in the next few months and am planning my maintenance..
#7
Rennlist Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Seriously, Give 'em back and go for a proper "X" pipe setup. You can get high flow cats too. The fires are usually the result of "Operator Error" thinking there's a limp home mode. Read up on here about it. Search is your friend.
Trending Topics
#8
Team Owner
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
those pipes may not fit your it looks like an extension was welded on to the right pipe a test fit would be good B4 you remove your old cats,
The 02 needs to read the ex gas, if not your may not run well
The 02 needs to read the ex gas, if not your may not run well
#9
Captain Obvious
Super User
Super User
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
I have the same looking one (less the extension) but the corssover pipe is open to the exhaust. However the air tube was a dead end.
#10
Administrator - "Tyson"
Lifetime Rennlist
Member
Lifetime Rennlist
Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
+1
Also, take a look at the FAQ at the top of the forum, a lot of good knowledge in there:
https://rennlist.com/forums/928-foru...questions.html
Also, take a look at the FAQ at the top of the forum, a lot of good knowledge in there:
https://rennlist.com/forums/928-foru...questions.html
#12
Captain Obvious
Super User
Super User
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
That's not a home brew. At least one of the big 3 used to sell them before the X hit the market. If it was home made, the balaning pipe wouldn't be oval and it's unlikely it would be all mandrel bent pipes.
#13
Addict
Lifetime Rennlist
Member
Lifetime Rennlist
Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
The extention was probably to fit it to the 85-86 stainless manifolds when fitted to the 16v heads....since it moves the three hole flanges one side forward and the other side back. So I doubt it will fit your car as it is.