As title really, want to do something else to mine so thought I'd decat it as it's cheap and easy. Have I not read that it causes the turbo to overspin if it's already mapped?

Don't want to take damaging the turbo as I do 1000s miles a month as this is my work car. Cheers

I've done that and mine has been fine. I'm running a shark map.

I might of imagined it then, I'm sure someone said the turbo overspins if you do this way round.

Does yours do the owl sound? Don't really want it to do that, I've got a twin 3" back box fitted

I might of imagined it then, I'm sure someone said the turbo overspins if you do this way round.

Does yours do the owl sound? Don't really want it to do that, I've got a twin 3" back box fitted

Apparently it can cause the turbo to over boost but mines been fine mate.

Nope no owl sound at all

Apparently it can cause the turbo to over boost but mines been fine mate.

Nope no owl sound at all

How long have you run yours like that? Does it make much difference?

How long have you run yours like that? Does it make much difference?

2 months or more now mate. Turbo spools up alot faster and it sounds so much better! Worth doing it just for noise, doesn't sound like a derv anymore!

2 months or more now mate. Turbo spools up alot faster and it sounds so much better! Worth doing it just for noise, doesn't sound like a derv anymore!

Does it really make that much difference to the spool up?? It's not like they're laggy anyway! My rs turbo that was running 1 bar was laggy as ****! How much louder is it with decat? Are you running standard back box, mufflerectomy or custom?

I recent logged a vRS that had a de cat after a remap. To my surprise it never overboosted. Would like to log more to see if it was a one off.

Mmm interesting, my cars running a custom map from Jabba. Iv always ummed and aahhed about fitting a decat, as I'm sure uv also read it causes the turbo to overboost.

On my old mk3 Ibiza Cupra the Milltek race cat I had fitted mated to a Milltek system made a big difference to how quickly the turbo spooled up and felt more responsive.

Plus I'd like maybe a little more noise lol

Does it really make that much difference to the spool up?? It's not like they're laggy anyway! My rs turbo that was running 1 bar was laggy as ****! How much louder is it with decat? Are you running standard back box, mufflerectomy or custom?

I noticed it straight away yes mate. Not much louder tbh, it's more turbo noise all of my mates comment on how nice it sounds now, it's not overly loud though you cannot hear it unless you put your foot down.

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Does it really make that much difference to the spool up?? It's not like they're laggy anyway! My rs turbo that was running 1 bar was laggy as ****! How much louder is it with decat? Are you running standard back box, mufflerectomy or custom?

I noticed it straight away yes mate. Not much louder tbh, it's more turbo noise all of my mates comment on how nice it sounds now, it's not overly loud though you cannot hear it unless you put your foot down.

At first I ran a mufflerectomy and liked the noise, decided to go back for a full decat. Soons as I left the place I secretly hated it! Was awful, loud, and noticed a big drop in power. Turbo did spool up faster but I could feel a lack of back pressure when it wasnt on boost!

So 5 weeks later I went back for a 5" diameter back box put in, bought the noise down, and also bought that boost back in power. Really happy with my current setup and best of all it's works out to have only cost me £245!

Edited 8 March, 201313 yr by DanHam

I noticed it straight away yes mate. Not much louder tbh, it's more turbo noise all of my mates comment on how nice it sounds now, it's not overly loud though you cannot hear it unless you put your foot down.

At first I ran a mufflerectomy and liked the noise, decided to go back for a full decat. Soons as I left the place I secretly hated it! Was awful, loud, and noticed a big drop in power. Turbo did spool up faster but I could feel a lack of back pressure when it wasnt on boost!

So 5 weeks later I went back for a 5" diameter back box put in, bought the noise down, and also bought that boost back in power. Really happy with my current setup and best of all it's works out to have only cost me £245!

I'm running a sportex 3" twin back box off a escort I think lol. Had it laying about so thought I'd stick it on. Should this provide enough back pressure? Some people run no boxes at all do the they??

I'm running a sportex 3" twin back box off a escort I think lol. Had it laying about so thought I'd stick it on. Should this provide enough back pressure? Some people run no boxes at all do the they??

I'm not to sure mate I'm no exhaust specialist, some run no boxes at all, I did so I'm sure anything is better than nothing

This is my back box by the way, didn't like the oval one I was going to put on

Mmm interesting, my cars running a custom map from Jabba. Iv always ummed and aahhed about fitting a decat, as I'm sure uv also read it causes the turbo to overboost.

On my old mk3 Ibiza Cupra the Milltek race cat I had fitted mated to a Milltek system made a big difference to how quickly the turbo spooled up and felt more responsive.

Plus I'd like maybe a little more noise lol

Exactly same boat as me I really don't know whether to decat it or not. I'm really tempted to as it's basically free power as I just need to weld in abit of pipe

I'm not to sure mate I'm no exhaust specialist, some run no boxes at all, I did so I'm sure anything is better than nothing

I know petrols need some back pressure but not 100% on diesels, I'd sooner run something in it like you said though. You got a pic of your 5" exhaust? Only ever see twins like mine or ovals

That's the only one I have mate, it should look good if your viewing on a calculator haha! It was taken in low light with my cry-phone!

As others have suggested, it would be worth getting your map checked/tweeked to ensure that the turbo is not overspooling.

Had my vRoomster tweeked @ Shark last week and they also extinguished my CEL generated by the failed ASV

That's the only one I have mate, it should look good if your viewing on a calculator haha! It was taken in low light with my cry-phone!

I was expecting a 5" round off a scooby pmsl. Looks good though

As others have suggested, it would be worth getting your map checked/tweeked to ensure that the turbo is not overspooling.

Had my vRoomster tweeked @ Shark last week and they also extinguished my CEL generated by the failed ASV

The only problem with that is I bought it already mapped and don't know who did it. It's a smooth map though although I've never compared it to another mapped one

I was expecting a 5" round off a scooby pmsl. Looks good though

Ohh right haha sod that mate it would hit the floor! My old twin pipe would of hit a curb of if I'd have reversed close enough!

The diameter of the actual silencer is 5" mate. 4.5" would give a bit more noise though.

Ohh right haha sod that mate it would hit the floor! My old twin pipe would of hit a curb of if I'd have reversed close enough!

The diameter of the actual silencer is 5" mate. 4.5" would give a bit more noise though.

I thought it would be on the floor that's why I wanted a pic lol. Mines quite low down especially since I slammed it on the coilovers. The overall I offered up was too small but I like the look of yours

I thought it would be on the floor that's why I wanted a pic lol. Mines quite low down especially since I slammed it on the coilovers. The overall I offered up was too small but I like the look of yours

I've never seen a tip like mine before, looks kind of standard but it isn't, it's a universal stainless steel one I found on eBay then all the clamp area was cut off and welded onto the system

I've never seen a tip like mine before, looks kind of standard but it isn't, it's a universal stainless steel one I found on eBay then all the clamp area was cut off and welded onto the system

Looks good anyway, if I was going for a oval that's the one I'd go for

Looks good anyway, if I was going for a oval that's the one I'd go for

Have a look on eBay mate, it's known as letterbox style