DP + exhaust, cat or no-cat???

[Lucio Bravo]

I live In Johannesburg which isnt at sea level and I've heard that by removing the catalytic converter up here at altitude i run the risk of blowing my turbo as these bad boys dont generally last at altitude under pressure...

I'm looking to fit in a larger down pipe (76mm) into a 63mm straight pipe with one muffler on? so whats the take on removing the cat? I've heard so many different opinions from different people who should know what they're taking about but its all been no help?

also looking to change the turbo for something meatier down the line, possibly a VNT17/22 or a GT22 of a BMW 330d..

any suggestions?

 

[Yosh]

Experience has proven time and time again @ JHB alttude, the de-cat will result in turbo failure...High flow cat is your best bet bud...

 

[Lucio Bravo]

but Yosh so many guys give me so many stories? Frik said no point doing the DP and zorst with the Cat in? another tuner said he'd map the car and dp and zorst wont make a big difference? alex at Mr Turbo says de-cat wont blow turbo? i'm lost bru.... i want the DP/ zorst for a decent tone and to get rid of the higher EGTs faster but these guys confuse me big time?

 

[Yosh]

Maybe look at bigger diameter boost pipes ie. from PASSAT...I will put my left nut on the line; de-cat will destroy your turbo here in less than 20K Km...Spoke with Myan from CPI and he is also advising his clients against de-cat(here and in durbs)...I would run 63mm DP with a high-flow cat bud; nice tone with safer power gains...

 

[CupraOl]

What's the theory behind the idea that de-catting a TDi will blow the turbo?

 

[CupraOl]

Any more info on my question above chaps?

 

[CJRamze]

Considering Dervs require NO back pressure I don't see how any pressure would affect it?
Saying that High Altitude is not something we really experiance here however I must say something

Even if you have a Cat, A downpipe and an exhaust will make alot of difference to how freely it revs!

 

[knight85]

was gonna say we dont really expereince high altitude so would have no idea..

im running full milltek turbo-back system with decat and have no probelms

 

[Yosh]

Hi guys sorry for the late reply...The miltek cat-back system works perfectly here but as soon as the dervs start de-catting the VNT turbo is breaking. This is hardly conclusive proof but seems to be the trend...This seems to only be happening @ JHB which is approx 1400m above sea-level...