Dump Pipes

[paolob]

i've actually heard downpipes with really good quality cats still throw CELs such as the AWE one. They said mine wouldnt but another member who has the downpipe as well has a CEL still lit but he has ordered a fix for it. Heres a pic of mine:

[smoothcall]

I intend to change my dump to something more free flowing and with only one high flow cat. I don't like the look of the Xforce dump as the cat is too close to the turbo for my liking. I've seen all the big brand dumps which I'm sure are a great product but I'd rather not have to sell a kidney to afford one of them.

I found this thread dump pipes - VW GTI Forum / VW Rabbit Forum / VW R32 Forum / VW Golf Forum - Golfmkv.com which has some good info and pics of the OEM dump.

What dump are you running, what brand or did you have one made and at what cost ?

I'd suggest you find out from the sw vendor what spec pipe they recommend. Some work best with 2.5" or 2.75", others are ok up to 3"

[shinygti]

Excellent information there mate. Now I know why the Eurojet dump has a spacer for the 2nd 02 sensor. Have you got any photo's of your custom dump ? Also where does it join the OEM system ? Did he use an existing joint or did he cut the existing system to join ? Good to hear noise levels haven't been effected too much also. Thanks shinygti.

Dont have pics but will jack it up this weekend and take a few. We joined mine just before the join of the stock one and put a flange join on it. As someone said if its a good flowing cat it will put a cel light up but its ok it just means it is flowing better than the computer is maped for it to flow and thus it thinks that your cat is stuffed and not working properly but dosent affect the car.

The pics you put up of the bump pipe look realy good. Mine looks similar to the the that paoblo put up and am thinking bout heat wrapping mine from the turbo down to the cat just to try keep things a bit cooler down the back of the engine. Think it cant hurt ???

[9 iron]

downpipes on mkv gti

ok... just a novice trying to understand this downpipe business.

So the mkv gti actually has 2 cats... 1 practically in the engine bay, right after the turbo, and another on the same section of pipe, however under the car, just before the 2nd O2 sensor??

But if you remove, and replace the oem downpipe, you are effectively getting rid-of both, (cos they are on the same pipe) and new downpipe should have at least one, to take care of environmental issues, and the law?

Can you simply remove the internals of the 1st cat near turbo, and re-fit pipe? Is this a big 'no-no'....? If this can be done, what are the tuning options post this mod? Eg... Stg II Revo ok?? OR, is pipe as a whole still too restrictive for agressive tuning of this sort?

does this make sense.....?

[HOTHATCH]

Yes mate it makes sense. Who said you're a novice ?LOL.

You are correct in saying you are effectively getting rid of what they call the pre cat. That's the one right next to the turbo. Its there because it heats up quick as cats don't work untill they hit 800 degrees so I'm told.

I've seen a clip on Youtube from Germany where I guy does exactly what you suggested. He bashed out the pre cat from his OEM dump re-fitted the dump minus the pre cat leaving the other further down.

I believe in the tuning software you can turn off the CEL that would be caused by either a high flow cat or removing one. From my research on this I've found that most overseas cats are 100 cell and can cause a CEL (Check Engine Light) there are ways around this.

By using a spacer under the sensor thus taking sensor out of the increased flow. The Hitech dump uses a 200 cel cat which is Euro standard. I was assured by Lambros at Hitech that it would not cause a CEL.

For my tuner none of these scenarios is a problem.

Note the spacer/extension tube for the sensor on this AWE dump pipe.

[9 iron]

"The Hitech dump uses a 200 cel cat which is Euro standard"

so does this mean the larger cat that will remain (on oem pipe, at the bottom section) is a 200 cell - being euro standard? Or is it Euro standard on sports type exhausts?

thanks for your help, 'by the way'........

[HOTHATCH]

The oem dump pipe contains two cats. The Hitech as with all the others only have one cat. Hitech have had theirs tested for emissions and their singe catted dump apparently had cleaner emissions than the OEM dump with two cats. I was shown a document to support this however, I must admit I didn't read it or look at the figures quoted.

I have also been in contact with a Vendor on Rexnet (WRX Forum) who has sent me photos of their new Golf Gti Exhaust system. Looks good in the photos however there seems to be only one muffler so I'm thinking it will be too loud for my liking. Have a look at ***TCPAUTO PERFORMANCE EXHAUSTS*** I don't think he's updated his website with the new exhaust yet. I have the photos which I might post up later.

[PirelliAC]

I am runnning an APT downpipe which i bought online from America, it seems to be good, cost me 350 USD delivered, however it was catless and i bought a magna flow cat and had it installed by a exhaust shop, runs well with the APR downpipe tune. I'm sure the APR Downpipe would be the best, but i did save myself about 1000 bucks. APT all the way for value for money, no engine light either....

[HOTHATCH]

Excellent!!!! Just had a look at the APT dump 3.0" Downpipe Assembly for FWD 2.0T FSI Turbo : atpturbo.com it looks really good. How much did your cat cost you ? About $300 ? Was the freight expensive ?

[PirelliAC]

freight wasnt too bad about $75USD from memory, but the cat was $150 AUS from online exhaust parts store called Best Mufflers, Remus Exhaust Systems and Muffler Specialists
works good.

[adzy]

Excellent!!!! Just had a look at the APT dump 3.0" Downpipe Assembly for FWD 2.0T FSI Turbo : atpturbo.com it looks really good. How much did your cat cost you ? About $300 ? Was the freight expensive ?

That site claims a 30 WHP increase with just the APT dump? How could this be when other companies in Australia (with our better quality fuel) claim 15 WHP increase with a re-tune also?

[HOTHATCH]

Those figures quoted are with no cat in the dump. Absolutely no restriction at all.

[adzy]

Those figures quoted are with no cat in the dump. Absolutely no restriction at all.

Ohh. no cat! That makes sense... man the thing would bark without a cat.