De-cat

[Liam_D]

Hey guys, Just wondering is it really worth getting a de-cat for a N/a? Or does it cause a loss of power, due to backpressure?

Just wondering because im looking at getting my exhaust done this month, and im unsure wheather to do a de-cat while im there.

Any help will be appriciated. Thanks

Liam

[ste91]

Theoretically a decat should give gains.

I am told "back pressure" is nonsense.

When you say you are getting your exhaust done, do you mean a full system?

[lukEp]

this might help http://www.uucmotorwerks.com/html_product/...etorquemyth.htm

[Liam_D]

Yes mate looking at getting a Custom manifold, decat and new middle pipe and keeping my current backbox.

Have any gains ever been proven from a de-cat as i dont want to spend the money for no reason.

[ste91]

Basically you want as much flow as possible without losing velocity, or something like that.

A cat is a restriction, it serves no performance purpose.

Have a read up on exhaust scavenging aswell.

[lukEp]

and another inc volocty http://www.thumpertalk.com/forum/showthread.php?t=659727

[Craig_N]

I going to get one made prob sometime in March so i can let you know.

But i have spoke with a few people who have decats on there n/a's and everyone one said they they noticed a difference.

Craig

[BAZ2CRAZY]

I would say big wins with a manifold

4-2-1?

Mitch

[rob_bower]

im going to try and get mine finished off this month so we can all share notes!!! lol

[DavidAshton]

I noticed a nice difference when i put a de-cat on my n/a. But i kept the middle box and SR backbox. Maybe a full system would not be such a good idea with a de cat, it will be silly loud.

[rob_bower]

that depends if you still running a middle box!!!

[Amjad]

Craig & Rob do let us know how you get on

I'm thinking of getting a decat too

[Starlet__SR]

I wasn't running a midbox on the SR in its last few months, sounded kinda like a supersprint system lol, you'll notice the engine revs alot freer and easier than when the cat was fitted, but you'll lose a bit of the bottom end torque.

Damien

[Amjad]

Damien did you remove the mid-silencer AND the cat?

[Craig_N]

I dont have a middle box on mine and yeah does rev alot better than my old exhaust but it is load, i have been given quotes of like £85 for one so will let you all know when i get it done and i will be getting a printout at the rolling road meet so i will see if it does make any difference.

[Starlet__SR]

Damien did you remove the mid-silencer AND the cat?

Nope, kept the cat, just used a section from behind the cat all the way to the backbox, alot louder and raspier, was worth doing

Damien

[Liam_D]

Think im just gonna get the manifold done and get a new middle pipe, because i really dont wanna lose the low down power and i dont want it to be any louder. Those that know my car know that it is silly loud already.

Would be nice to see any RR print outs that show noticable gains.

What about if i get the mani and de-cat done and leave the middle pipe in place?

[Starlet__SR]

And what are you gonna do come mot time when it comes to the emissions test? Keep the cat, ditch the midbox, the newer free flowing manifold will outweigh any restrictions the cat makes, possibly a sports cat with fewer cells per inch?

Damien

[Liam_D]

Mots wont be a problem dude, but i am starting to think i want the cat in there as i still want the car to be legal just incase.

Think im just gonna get the mani and then get the Middle box removed like you said, and then maybe some sort of sports cat in the future.

I really dont want the car to be any louder as its quite rediculous now. lol.

Going to get this priced up sometime next week!!

[Starlet__SR]

Mots wont be a problem dude, but i am starting to think i want the cat in there as i still want the car to be legal just incase.

Think im just gonna get the mani and then get the Middle box removed like you said, and then maybe some sort of sports cat in the future.

I really dont want the car to be any louder as its quite rediculous now. lol.

Going to get this priced up sometime next week!!

There is that too, it is illegal to drive without a cat, a sports cat is the best option, most standard cats are 400cpi, as with a sports cat, they're around 200cpi, better flow but still legal, the cat will suppress the sound, but the main exhaust volume is controlled by your backbox,

Damien

[b4d1sy]

I did have a de cat made a nice difference and change the sound a little 2

[Liam_D]

Been to get this priced up today, im going to be looking at £400 for a full custom Manifold and a decat pipe, which i dont think is too bad considering that this guys work is top quality.

Think ill be booking that in next month

[Dean @RW-Developments]

liam get an interchangable decat thats what i had but i must say i didnt have any middle box and when i had the decat in the power gain wasnt noticable till high end power ... the interchangable decat/cat was mint though i was always swapping it took like 10 mins to chage over! only cost £60. also try www.mijperformance.com they do all my work and aint too far from you!