75 Diesel decatting.
 

Convinced as I am, that a decat will boost the power of my Synergy equipped 75CDT from 148.56bhp to 155 or more, I am embarking on a decat project.

I have ordered a Sebring back box (cat back) and have found a supplier of stainless pipe and reducers so hopefully, attacking the one piece orginal system with a hacksaw and then welding in the decat pipe, should bring about a significant improvement.

When I decatted my 45, it was noticeably more responsive, with much reduced turbo lag, and a good 'free revving' feel to it. I never got around to dyno testing it so can't say what it did to the bhp figure, but the mid range torque was superb. It felt very petrol like.

I've a feeling this will be the case with the 75 - the standard cat and system may be okay for 115 or even 130bhp, but not for 150!

Ron

That sounds like a top project ron, it's somthing I am concidering myself for next year. Will be intrested in your results:drool4:

Scotty1

Sounds like a good one Ron. Would doing it impact on MOT emissions check at all?

Mike

No, absence of the cat has effect on the smoke test and one is not actually required for the mot.
The exhaust will smell, although using veg oil is one way round this!

Ron

Hmm.... will be very interested in the results of this :)

Ah yes -----Veg oil thats a whole new topic !
used to run an old transit on veg oil and white spirit, then the inj. pump gave up, not sure wether it was the 170k miles or ' the mix' that did for it.
Gave up after that as everything else I had would be ££££££££££'s to repair
Andy

Apparently Lucas/CAV pumps don't like veg oil but Bosch ones seem ok.
Not sure about Bosch common rail types though, 20,000psi is a lot of pressure so it might be asking a lot of the pump to generate this with something more viscous than derv. At the very least I would run it through a fuel heater and dilute it with derv in cold weather.

Ron

Your going to have Green Peace knocking at your door.

:D :D :D

I say go for it..

Used to run my Mitsubishi 2.8 TD on 50/50 veg oil mix, used to smell like a chip shop from behind. Other than that, the performance was unaffected!

I need to check this but I think that a cat is required for the MOT as they have been strapped to cars since 1991 and are now mandatory. I could be wrong but reading the stuff that I do a cat must be in place.

I shall confirm (and besides de-catting doesn't really do much for the emission in fact it throws things to the wall with regards emissions limits, CO and CO2 limits as well as the OBD requirements and if the system is worth its salt the MIL will activate as the OBD system is triggered) all of this information but I personally feel that taking a cat off a car is not a clever thing to do.

I know that the strangle the engines performance (they are even worse with a DPF - Diesel Particlate Filter) but they are there for a reason.

I shall check! It's a long and on going debate!

Nic