De cat pipe help!?

Yonner Gti · Post by **Yonner Gti** » Wed Apr 19, 2006 2:00 am

Hi guys. I am after a De cat pipe for my GTi. I have a stainless Mongoose from cat back. I been told you can gain upto 10bhp when you decat it. Any info on were i could purchase one from. Or any one got a Decat on there gti that they recommend
Thanks Guys

RICHARD HARPER · Post by **RICHARD HARPER** » Wed Apr 19, 2006 12:27 pm

You could try going to a place that does custom exhausts (powerflow etc)
and ask if they can make you up a bit of pipe suited to your existing system.
Thats where i got mine.
Click on my user name and search my posts, theres a pic of my decat in there somewhere.

Jordan · Post by **Jordan** » Thu Apr 20, 2006 2:52 pm

Just getting round to this at last. Going to get it done in the next couple of weeks.Got a bit of pipe so thinking bout doing it myself. Mot and timing belt getting done as we speak.

brianpologti · Post by **brianpologti** » Thu Apr 20, 2006 6:15 pm

had mine done at powerflow, they left the extra sensor on after the cat, been told that it wouldnt run correctly otherwise, that was on club lupo site, on a lupo gti, but a lupo gti has different ecu so not sure, my car does feel a bit quicker but it is louder,

RICHARD HARPER · Post by **RICHARD HARPER** » Fri Apr 21, 2006 8:59 am

YONNER,

What mods have you done so far that you're pushing out 138bhp ?

Just wandered as you have no de-cat

Grum · Post by **Grum** » Sat Apr 22, 2006 6:54 pm

i would'nt go by what gains people say a de-cat can give you!

i had a custom de-cat on my gti, second lambda sensor still being used, put the cat back on for MOT and it actually felt better to drive than it did without the cat!

id say that if u do get de-cat then there is special threaded sockets you can get to put over the second lambda sensor (like a blanking plug) instead of using it in the exhaust.

the reason for this is that the second sensor should get clean air after gases go through the cat, without the cat, the sensor is getting dirty air so the ECU thinks there is somethin wrong!

if u cover the sensor instead of using it then it wont be getting dirty air and should work better for performance!

dont quote me on this tho as i havent tried it myself, i just know that it works with some other cars!

Jordan · Post by **Jordan** » Wed Apr 26, 2006 11:12 am

This is a good point. I'm just about to fit my de cat but don't know what to do now if i should drill the hole in the piece of pipe for the sensor or just leave the sensor off it.

Jordan · Post by **Jordan** » Thu Apr 27, 2006 4:58 pm

Has anyone got any info on this. I've got a piece of pipe that will fit for
a decat. Do you think i'll be able to just fit it and just leave the 2nd oxygen sensor off the exhaust altogether and it will be ok. Cheers.

Grum · Post by **Grum** » Fri Apr 28, 2006 6:25 pm

Jordan wrote:Has anyone got any info on this. I've got a piece of pipe that will fit for
a decat. Do you think i'll be able to just fit it and just leave the 2nd oxygen sensor off the exhaust altogether and it will be ok. Cheers.

it will be worth a try but make sure u get the blanking plug for the sensor itself so it wont be drawin in any air at all!

iv fitted a couple 4 branch's on C2's and this is wot i had to do!

the bit u need just looks like a deep 19mm impact socket (if u know wot it looks like u'll understand) and the sensor just screws into it so it gets sealed off from any air.

Jordan · Post by **Jordan** » Sat Apr 29, 2006 1:05 pm

Thanks for your help mate.Where do you get they plugs from. Just a motor factors or halfords or something like that.

Yonner Gti · Post by **Yonner Gti** » Tue Jun 13, 2006 12:19 am

Did any of you guys get ya De cat pipes on ya car and sort them sensors out?