CAT vs Decat

[sk8xtrm]

I have a quick question for you all on the above topic, ive put my cat back on feels so much more responsive but will a decat on the williams engine release many ponies :)

I know logically without a cat you lose low down torque and gain high bhp but i wanted to double check with these engines!

I have a RR session on 20th of this month so obviously want to gain the highest BHP I can. :lol:

Thank you

[northy]

fitting a decat is like loosing a passenger over a standard car.

[sk8xtrm]

fitting a decat is like loosing a passenger over a standard car.

:lol: Im loving that simile! Im guessing by that you would recommend one then!

I think its going back on then, need to make it a little less noisy then as with the devil straight through stainless it was frigging loud.lol

My mate it taking his valver to RR so we are having a little personal battle as have pretty much the same mods except his has chipped ecu and raised limiter.

[zmaster2k]

The same boat tbh! But gonna whack the decat on me thinks?!

[sk8xtrm]

The same boat tbh! But gonna whack the decat on me thinks?!

difficult one isnt it! The car actually feels quicker with the cat but i think thats because of low down response and torque! but I raced my friend in his Integra type R before with a standard exhaust and decat and was exactly the same, then I put a devil exhaust system on with the cat and raced him again last night and he pulled two cars on me, see logically to me the exhaust will give gains but ive lost and the major diffrence is a cat!

[sk8xtrm]

I think the solution for me is to weld in a centre box and remove the cat :)

Thanks for advise guys :)

[Purple]

Ran a straight through replacement for the cat (stock engine in high ambient temperature) for about a week before switching back to a standard cat. Lost quite a bit of low-end response on the straight through. Top-end did not improve either but, then again, I seldom rev past 6k. IMHO, a decat should make more sense in a modded clio, as there's more energy trying to get out of the exhaust.

[Tommo]

^^ I agree

I hated my decat, put cat back on after a week, waste of money imo. Williams is all about low-end torque and this is all lost with a decat.

[northy]

cat with standard exhaust is really slow compaired to decat and full system.

My 3 is back to standard and im a good 3 - 5mph slower now at 4,000 rpm (used to be 80mph)

[Coops]

:lol: you'll always be same speed at 4000rpm mate unless you change your rolling radius or gearing :wink:

[Coops]

oh and on my old valver it felt torquer with the cat on, but revved more freely up top with decat

my old williams was decatted and powerflow system, current one is standard system and cat still on and feels much quicker all round, but i think thats more the engines much much better so not a true comparison

[Yanoo_]

oh and on my old valver it felt torquer with the cat on, but revved more freely up top with decat

My French girl was exactly same (standard system with and without cat). Although it revved up faster with decat but the torque loss on low and mid rev range was noticeable. Now I'm using mine with cat + standard centre section + Devil backbox. It revs up quickly, pretty quiet and I don't feel significant torque loss. (by the way my decat is still for sale :) )

[schakal]

cats are for faggots imo .
if you want restriction bang on a log valver manifold :idea: :idea:


:P

[northy]

Seriously its not coops. Went straight from full system to full standard.


S L O W

[Wobba]

I've often had to switch back to my CAT, and I notice the difference immediately and I love it...at first. Once on roads where top power is required, you can feel its not as fast...its a sort of weird feeling, like the engine is gasping for air or out of breath compared to normal.

Driven Leighannes car the other day, you get in it and even though hers is a lot more standard than mine you can feel there is a bit more low down pull from the engine, despite her car not being a bit stripped like mine is. Mid range and up top it loses out though, spent hooours ragging the shit out of her car on Friday testing. Sideways all round the Burseldon roundabout was my favourite bit, can really get the tail into a decent slide with the extra weight in the back :) Being chased by several cop cars was fun too, they didn't catch me though as they were chicken shits at the red lights and didn't go straight through like I did.

Summeh's car had loads of torque low down but then he has some headwork.