Tuning JTD 115 Decat

[Halil]

I know alot of questions have been asked about decats but there are a couple of things i cant find the answer to:
1) Can both cats be easily removed and bashed out?
2) Will I get a lamda sensor failure by removing both

If anyone could also give me a brief run-through on how to do it (particularly the one on the down-pipe i.e. where exactly it is and how to get to it) then i would be very grateful

Thanks
HH

 

[rattystilo]

you don't get lambda sensor failure. You may get an overboost sensor trigger an engine fault when you rag the car but it goes off after 3 starts. The top one i used a new pipe from js tuning. Then i have a full stainless system which takes out the lower cat. Cost was about 500 all in which considering i needed a full exhaust i was happy to spend.

 

[Halil]

Cheers for your reply ratty, I have read the posts on your decat and it looks good. Good to know there are no lambda faults. Would there be any way to regulate the boost so that there is no overboosting?
As you may be able to tell, I am looking to spend closer in the region of £0 for the decat haha. I wanted to know if its possible to bash them both out and get away with it.

HH

 

[yampug]

do you have problems at mot time if you remove your cat? does it still pass emissions ok?

 

[MarkThompson4]

My mates VW Bora 1.9TDi (pd130) passed it's MOT emissions test no bother with the cat removed, don't see how a JTD can't

 

[Halil]

There are no emissions problems with diesels, they are only subject to the smoke test. Can anyone answer my previous questions please?

Thanks
HH

 

[rattystilo]

there was a bashed out cat for sale on here a couple of weeks back so yes you can bash it out. Do not breath the dust in tho. Regarding the rear cat it can be cut out and a new length of pipe put in. Any mates that work at an exhaust place?

 

[rattystilo]

if your car isn't remapped you shouldn't have a boost issue anyway. Mine was remapped before i decatted it hence sometimes in 4th gear it'll trigger the sensor. Doesn't do it in lower gears, just pulls hard

 

[Chris017]

I have just had my mot last week and the centre cat has to be there. I asked the guy and he had a Alfa Romeo gt Jtd multi jet 150 and the only way you could do it is to just smash the inside of the cat out as he has done, other wise it will be a mot failure.

With my cat it is a whole piece that connects to the centre box uswell so it's quite difficult to smash out, only way of doing it is to cut a square out on the top of the cat and smash it out and then weld it back. Easy job if you could get a lift get it welded and just put it back on the car then. No problems

 

[GizmOwin]

I have both cats removed and middle silencer removed and I've passed my MOT recently. I guess it depends how strict the place is.

Owen.

 

[rat20v]

are there much gains from removing the cats?

 

[Chris017]

How does your car sound without the middle silencer and the de cats? Have you got a standard back box.

 

[Peter Pick-Up]

http://www.js-tuning.nl/downpipe-8v16v-fase-p-128.html?language=en

About two months ago, I removed both front and rear cat from my 2004 Alfa GT jtd, and have put the JS downpipe and Ragazon cat replacement instead.
Meanly because of cost reasons, because both parts are a lot less expensive than the worn original parts.
Car runs great, sounds no louder, and last week, it passed our Dutch mot without problems....!

 

[Chris017]

So have you de cat the car yet?
How much difference does it make without the middle cat and a standard back box? This is one thing I do not know, many people have told me but I would like your opinion

 

[Peter Pick-Up]

I have an Ultersport rearbox, and the sound without the two catalysts is just a little lower, that's all, hardly noticeable inside...!
(But it is with a 150hp 1,9 jtd in an Alfa Romeo GT...!)

 

[rattystilo]

i have a stainless steel exhaust with a single box at the rear. from inside the car you don't notice it until you put your foot down then you get a deep rumble but it isn't too loud. Quite a unique noise actually that has to be heard.

Some will love it, others will hate it.

 

[Halil]

This all sounds good! I cant wait to decat my car, i am happy to smash out the one in the middle of the car, as long as it doesnt require any welding. Has anyone tried that on the one in the downpipe though? Or do you think my only option for that one is a new downpipe?

Thanks
HH

 

[rattystilo]

someone has done it as there was a downpipe with the cat smashed out of it for sale either on here or ebay recently. Tbh do the middle one, get it mapped or a tuning box on the car and you will get good gains without triggering the boost sensor when you boot it too long in 4th