Tommy_G Posted May 9, 2008 Share Posted May 9, 2008 well ive seen it mentioned, does it make any difference to the n/a?guess it would be minor. oh and how much, where from etctom Quote Link to post Share on other sites
DavidAshton Posted May 9, 2008 Share Posted May 9, 2008 My mate has a de cat in his SR and he hates it. Makes it so mega noisy (although he does have a full exhaust system) and he says its lost some power after having it done. So he is having it put back in. Quote Link to post Share on other sites
RobSR Posted May 9, 2008 Share Posted May 9, 2008 they dont lose you power....i just had mine cut out of the old syestem and a de-cat pipe welded in....im selling that soon, so if you want it give me a PM Quote Link to post Share on other sites
Tintin_SR Posted May 9, 2008 Share Posted May 9, 2008 yes my decat made it louder but theres nowt wrong with that lol and faster good one with the rola manifold Quote Link to post Share on other sites
Starletraje Posted May 9, 2008 Share Posted May 9, 2008 as far as i know the power gains/loss depend on the actual decat. if you lose too much backpressure in a N/A engine it doesn't expell the exhaust fast enough and essentialy bogs it down. so it has to be the right size, its like using a custom exhaust with a huge bore. you end up losing power over a certain diameter Quote Link to post Share on other sites
Sparky Posted May 9, 2008 Share Posted May 9, 2008 I will let you know when I get mine done Nah I heard it makes 1st and 2nd gear less "flat" Quote Link to post Share on other sites
Rich Posted May 9, 2008 Share Posted May 9, 2008 I will let you know when I get mine done Nah I heard it makes 1st and 2nd gear less "flat"Flat? with the rolla mani its anything but flat with vertually standard system ;)I was gona try get one booked in tommorow. I'll see how it compares with the standard system and with a decat pipe keeping the middle box and standard pipework.Would be good to get it made and take it to a dyno swapping it over on a second run like muddyell did with the manifold. Quote Link to post Share on other sites
Sparky Posted May 9, 2008 Share Posted May 9, 2008 I dont have a rolla mani though do I Dont rub it in ;) Quote Link to post Share on other sites
Liam_D Posted May 9, 2008 Share Posted May 9, 2008 I believe Bourkeys N/A engine that hes stripping has a 'Rolla mani on Sparky dude.I would also like to know the difference with a de-cat as i was thinking about it the other day. Quote Link to post Share on other sites
ste91 Posted May 9, 2008 Share Posted May 9, 2008 I believe Bourkeys N/A engine that hes stripping has a 'Rolla mani on Sparky dude.I would also like to know the difference with a de-cat as i was thinking about it the other day.he did have but it was sold before he posted the topic I think Quote Link to post Share on other sites
Dean @RW-Developments Posted May 10, 2008 Share Posted May 10, 2008 when i first had my ss exhaust system made i had a cat back, but i had the middle box removed. a few months after i had an interchangeable decat made so i could still put the cat back in for my mot. i ended up putting the cat back on the next day as the police kept pulling me and when i let off the throttle it made the a horrible farting noise. it did spit plenty of flames though if you get all your boxes removed it will be LOUD! Quote Link to post Share on other sites
Sparky Posted May 10, 2008 Share Posted May 10, 2008 Yea I did notice Liam but that was sold before he even removed the engine so I didnt bother asking Quote Link to post Share on other sites
alan0387 Posted May 10, 2008 Share Posted May 10, 2008 I am undecided whether to make my decat standard 1 3/4" or a slightly larger 2". i am thinkin larger because of the volume of air inside a cat and centre box (also being removed), will need to be matched otherwise it might cause more back pressure? any body have a decat on an n/a? what diameter pipe is yours? i only have a standard exhaust too. Quote Link to post Share on other sites
Bourkey Posted May 11, 2008 Share Posted May 11, 2008 Well i've had a few systems to give you some idea.The one that was one my car when i bought it was straight through no cat. It was mega loud and popped, banged and flamed a little. It was a touch too loud for me so i got another standard system with the cat but the middle box out. This was slightly quieter and was a noticable different in speed. It was quicker without the cat. Then i had a system which had the cat removed and the middle box in and that was the best in my opinion. It wasn't too loud and was the quickest out of the lot.I now have the smae backbox on my car but on the Glanza system and im guessing Dub is 100% correct as it sounds nothing like it did when it was n/a. It is quieter and more decreet. I personally think it has a fantastic note to the exhaust now. Just how i like it.Hope this helps budBourkey Quote Link to post Share on other sites
alan0387 Posted May 11, 2008 Share Posted May 11, 2008 thanks guys, ill remove the cat and see how it sounds first! i might still cut out the middle box and make up flanges so i can remove it if i wish? hopefully ill get that done in the next 2 weeks. one of the guys on my apprenticeship course is bringing in a backbox 2mo so hopefully if it is alright i will get it! Quote Link to post Share on other sites
Rich Posted May 12, 2008 Share Posted May 12, 2008 Got my decat on saturday, Its quite loud due to the backbox and It has improved the performance quite a bit, power comes in a bit earlier and I definatly need to raise the rev limit.I am using standard exhaust plus decat (same size diameter) and backbox.Will need to get this dyno'd again. Quote Link to post Share on other sites
RobSR Posted May 12, 2008 Share Posted May 12, 2008 ^ does it rasp like a good un?! ....decat's with the same dia. pipework on stock system, gives you the bumble sound.. Quote Link to post Share on other sites
Rich Posted May 12, 2008 Share Posted May 12, 2008 Doesn't really rasp as I got me mate to do a drive by for me on a quiet road in the middle of nowhere. Sounds deep and roary untill near the rev limit then its a bit tinny... Quote Link to post Share on other sites
alan0387 Posted May 12, 2008 Share Posted May 12, 2008 Did you leave the middle box in yeah?? Quote Link to post Share on other sites
Rich Posted May 13, 2008 Share Posted May 13, 2008 Yeah its standard exhaust with a backbox and decat.I do want to get a same diameter stainless system with 2 boxes and a quieter rear box though Quote Link to post Share on other sites
ste91 Posted May 13, 2008 Share Posted May 13, 2008 Would it be worth doing a de-cat on a completely standard exhaust? (standard backbox aswell) Quote Link to post Share on other sites
Liam_D Posted May 13, 2008 Share Posted May 13, 2008 I would also like to now that ^^^^^ Quote Link to post Share on other sites
RobSR Posted May 13, 2008 Share Posted May 13, 2008 yeah it does make a little difference, but like i said, it rasps at around 3500-4000k and sounds gay. Quote Link to post Share on other sites
DavidAshton Posted May 13, 2008 Share Posted May 13, 2008 How much did it cost you rich? Didnt realise you could decat a standard system. Going get mine now, ive only got the tte backbox off a SR so i would think it would be pretty much same as de cat on on standard backbox. Ill try and get it done ont weekend and let you know how it goes. Quote Link to post Share on other sites
Tommy_G Posted May 15, 2008 Author Share Posted May 15, 2008 id also like to know cost nd where you got it from if its ok. plus can it be changed easily for MOT time? also nechance of gettin a vid of the drive by or sound it makes now? Quote Link to post Share on other sites
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