Ok my 2.5" Revhard downpipe doesnt line up with my GSR exhaust. I realize it was designed to probably use a flex pipe or ball joint connection to the cat.

I would like to use a flex pipe to bridge the gap between the downpipe and cat however that is exactly where I wanted to put the O2 bung. I wanted it to be as close to the stock location as possible becasue thats where the pre-existing harness is and theres room for the sensor.

So my questions are:
1.) How long should the flexpipe section be? And should I start it further up the downpipe, under the oil pan?
2.) Where the hell do I mount my O2 wideband now?

Short 3"


Not only is it short its off center by 2" which pisses me off more than being short.

 

does the downpipe slope down also?

 

yes slightly. its firmly bolted to the turbine too.

 

I think all you need to do is cut the downpipe,
so its even shorter than it already is.

and just attach a flexpipe imbetween that and the cat... and you'll be set!

 

Take off that CAT
I also would cut it at the end of the oil pan and put the flex right there, just extend your wires and you'll be good.

 

some pictures of your guys' finnished downpipes would be great.
thanks for the ideas.

 

flex sections come in many different lengths....you can buy a longer flex, throw flange on it, and weld it to the dp (cut a little off like he said) so that it bolts up to the cat

 

is there a suggested or particular length of flex that is commonly used among the boosted guys on here?? what I'm getting from this thread is that after the oil pan is the best position...(thus use whatever length it is from about the oil pan back to the cat??)

 

You might want to cut the downpipe near the turbo outlet flange and rotate the pipe so it points straight to the cat convertor. Then reweld it

 

I reccomend putting the o2 sensor in front of the cat (unless your running two!?). Either way, you want it to get nice and hot. To connect that pipe to the cat, you need the flange for the cat, and then a piece of flex would work niceley. I used the cheapo autozone "exhaust repair kit" which is like 30-40" of flex pipe, dirt cheap. The biggest they have it is 2.5 though. Works well.

Good luck.

 

so thats what the inside of a cat looks like, funny my 3" is hollow, guess it's "an imagination converter"

 

ObdI or obdII?

If you plan on keeping the cat just buy a flex sextion 6-8 inches, cut the downpipe shorter and weld in the flex pipe, add a flange and bolt it to your cat.

Option 2 ditch the cat, weld flex section to end of current downpipe, and then add a few inches ot end of flex with flange and bolt to exhuast.

Either way get a flex pipe

Just though of something My roomate has a damaged downpipe hes been trying ot sale with no luck,but I can see if hes willing to part/cut it and sell you the end section which has a 2.5 flex, with some piping after it and a flange. **** you could buy that line up the flange with you cat or exhuast, and then cut Revhard Downpipe where it meets your new sections and weld. Problem solved. It has an o2 bung welded in so that would alos help your situation. Pm me if you have nay questions, I'll look over the Dp when i get home

 

how do you mount your wideband o2? cut a hole in the downpipe and weld in a bung... noone ever said you didnt have to fab anything to go turbo. why are you trying to hook it up to stock exhaust anyway?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bretx0r &raquo;</TD></TR><TR><TD CLASS="quote">why are you trying to hook it up to stock exhaust anyway?</TD></TR></TABLE>

Stock exhaust? Look at the sig. Apex catback

 

do what i told u to do nugga!!

 

I would cut at the first straight part of the DP as it goes under the car and put in the flex. Then it gives you more arc (translation at the end of the pipe) at max flex, since a flexpipe can only flex so much. This is to ensure you can get the end of the DP to the Cat on less of an angle.

 

You might have to shorten up the exhaust a bit so the cat sits as far back as possible. To allow room for the o2 bung/bungs inbetween the axle and crossmember. Yours looks pretty tight though. Here is what I had to do for mine

 

^^^

THIS IS WHAT I TOLD U TO DO

 

Make sure the pipe is clearing the block completely.
If the pipe was made for that car, it should line up.
I had that same problem with my drag downpipe.
I had to shave a small portion of my block to get the downpipe to line up.
Check for any obstructions from the block area.