Nerih 0 Posted September 26, 2005 Report Share Posted September 26, 2005 Hi, my torque curve peaks near 5k rpm, but my max power is near 6k.What adjustments (timing/fueling) can you make to move the torque up the the rev range.would a restrictive exhaust (too much backpressure) contribute to this problem? Link to post Share on other sites
Seademon 0 Posted September 26, 2005 Report Share Posted September 26, 2005 Not too sure wether it would help your torque curve but as your running a S/C the less back pressure you have the better I think. Link to post Share on other sites
Nerih 0 Posted September 26, 2005 Author Report Share Posted September 26, 2005 so getting rid of the cat is probably a good idea until MOT time right? Link to post Share on other sites
Seademon 0 Posted September 26, 2005 Report Share Posted September 26, 2005 Yeah - will fail the MOT but does make a difference to the performance - not a terrible to do just a bit of a pain in the backside to do it once a year! Link to post Share on other sites
Nerih 0 Posted September 26, 2005 Author Report Share Posted September 26, 2005 does anyone here have a cat bypass? it might not fail the mot , you never know hehe. Link to post Share on other sites
simey 0 Posted September 26, 2005 Report Share Posted September 26, 2005 It will fail the mot having a cat bypass, as your car is charged I strongly recommend a cat bypass due increase in hydrocarbons which will damage the cat.All I tell the mot tester's: The car hasn't a cat on so I've put the cat in the passenger seat to change for the car to pass the mot. They usual say bugger that I'll get my hands dirty and stick the probe up another cars exhaust. 10 quid cash always sorts it!! Link to post Share on other sites
The1andonlygav 0 Posted September 26, 2005 Report Share Posted September 26, 2005 i spoke to miltek and they strongly reccomend a cat by-pass along with the cat bat (obviously, they'll make money!). But aparently you'll need it mapping again?! He put the full system on a charged vr and it ran like poo until the re-map.Its just money, money, money! Link to post Share on other sites
Ultimatetune 0 Posted September 26, 2005 Report Share Posted September 26, 2005 gav, that sounds very OTT, but like you say they are trying to make money etc.....never had to remap any car i have owned after a decat Link to post Share on other sites
Ultimatetune 0 Posted September 26, 2005 Report Share Posted September 26, 2005 did not have to remap my car Link to post Share on other sites
binliner 0 Posted September 26, 2005 Report Share Posted September 26, 2005 I had mine remapped (dastek) after fitting a decat and straight through 2.5" centre section saw the bhp go from 252 to 265 and torque went up from 232 to 252lb/ft! Link to post Share on other sites
Eat this 2 Posted September 26, 2005 Report Share Posted September 26, 2005 does anyone here have a cat bypass? it might not fail the mot ' date=' you never know hehe.[/quote']mibe just scrapes through with a decat and i would deffo expect it to flow better at high revs Link to post Share on other sites
Nerih 0 Posted September 26, 2005 Author Report Share Posted September 26, 2005 rob, i hate joo, you know i want that car...give me, i'll trade you my vr, for your skyline, it was so comfortable, on the way home i fell asleep in it too!-- right justin, thats the kind of factual metric i was looking for, i have one on order, but was wondering if it was worth it, becuase of the MOT issues. i dont mind paying 10 quid more for my MOT hehehe. who knows, i might be like eat this and get thru without any problems (still gotta wait until next year for mot tho!) Link to post Share on other sites
binliner 0 Posted September 26, 2005 Report Share Posted September 26, 2005 tbh I picked the car up from the exhaust place, drove the 20 or so miles to the garage and was smiling all the way it sounded and drove like a different car... by the time I got there I didnt care what the figures were because I could feel the improvementI should point out that this was a custom centre section from downpipe to backbox hand built on my car (nearly £400 worth!) Link to post Share on other sites
mightyvr6 0 Posted September 26, 2005 Report Share Posted September 26, 2005 I think the stock exhaust even with a decat is restrictive as you can here the air rushing through the system on acceleration as if the exhaust can't cope with the extra air-flow. Link to post Share on other sites
Ultimatetune 0 Posted September 26, 2005 Report Share Posted September 26, 2005 ideally you want a 2.5 inch system from down pipes back, but preferably with a larger port down pipes (manifold etc) Link to post Share on other sites
Nerih 0 Posted September 26, 2005 Author Report Share Posted September 26, 2005 ultimatetune is sorting it for me, so i'm guessing it'll be good. come on rob, when will i see this pipe work .binliner :- mines not 400 quid lol, its slightly less, probably wont make as much power, but maybe it will open up the top end a bit more, what you think? Link to post Share on other sites
FishWick 21 Posted September 26, 2005 Report Share Posted September 26, 2005 Back pressure is not so much of an issue with chargers as they're crank driven (as you know), so you won't get exhaust back pressure trying to stall the turbine blades like you get with restrictive exhausts on turbo engines.CAT and MOT. Incorrect. You don't need one post 92 to pass the MOT. What you car must pass is the emissions, with or without cat and that's what the lambda is there for, besides, if you get a SupersSprint bypass like what I've got on mine, it looks like a sports cat and that's what you tell the MOT tester, it's a 100 cell sports Cat ;-) The absence of sulphur smells seldom catches their attention and if you're 'friendly' with your tester, they'll over look it..... I mean, they let Allegros and Metros through the test, so......Mine has the factory exhaust and said SS bypass. If the Corrado VR lientz system is anything like the Golf VR system, then it flows plenty, just don't believe the hype with exhausts...... just remove the biggest restriction, the cat. Link to post Share on other sites
matth76 1 Posted September 26, 2005 Report Share Posted September 26, 2005 ideally you want a 2.5 inch system from down pipes back' date=' but preferably with a larger port down pipes (manifold etc)[/quote']What is the diameter of a Milltek system (cat back)? Is it 2.5"? Link to post Share on other sites
FishWick 21 Posted September 26, 2005 Report Share Posted September 26, 2005 Milltek will do a 2.5" if you ask (at extra cost), otherwise it's the standard 2.25" bore.2.5s, I've found, will give you gains at the top end, at the slight expense of bottom end torque. Link to post Share on other sites
Nerih 0 Posted September 27, 2005 Author Report Share Posted September 27, 2005 thank kev. i cant wait to get my cat replacement in. Link to post Share on other sites
binliner 0 Posted September 27, 2005 Report Share Posted September 27, 2005 If the Corrado VR lientz system is anything like the Golf VR system' date=' then it flows plenty, just don't believe the hype with exhausts...... just remove the biggest restriction, the cat.[/quote']trust me the syncro system is completely rubbish... 2 cats, 2 suitcase boxes, pipes the size of pea shooters... it had to go! Link to post Share on other sites
mark@vagworx 0 Posted September 27, 2005 Report Share Posted September 27, 2005 lol. Definately decat it.It pulls much crisper without the cat in place. Get your self a decent single box system nerih, you can't go wrong. Link to post Share on other sites
anorak 0 Posted September 27, 2005 Report Share Posted September 27, 2005 Nerih,5000rpm sounds quite high for peak torque. Mines at about 4k and standard is 4200 I think.As far as moving the torque peak up the rev range goes that's what everyone after more power wants. 260lbft at 6500rpm would give you 310bhp.Have you posted your graphs - be interesting to compare. Link to post Share on other sites
FishWick 21 Posted September 27, 2005 Report Share Posted September 27, 2005 trust me the syncro system is completely rubbish... 2 cats' date=' 2 suitcase boxes, pipes the size of pea shooters... it had to go![/quote']Yeah that does sound restrictive! The Corrado system is nothing like that thankfully. I really rate it. My Milltek liberated precisely zero hp over the standard one, so the standard went back on and Milltek got their exhaust back. Link to post Share on other sites
Nerih 0 Posted September 27, 2005 Author Report Share Posted September 27, 2005 ive given it to some people as attachments/links if you want a copy, pm me. Link to post Share on other sites
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