Ryan_EP82 GT Posted April 30, 2015 Share Posted April 30, 2015 ^^^^ yessssssssssss Quote Link to post Share on other sites
Arnold Posted April 30, 2015 Share Posted April 30, 2015 That's an awesome photo Quote Link to post Share on other sites
epcashin Posted April 30, 2015 Share Posted April 30, 2015 Any goodPhotos of 3" done out the side ? Are you goin for drivers side or passenger straight out ? Not much space wen ya want to go straight out instead of the loop Quote Link to post Share on other sites
bucketep91 Posted April 30, 2015 Share Posted April 30, 2015 Always going to be one arsehole copper will do u for it. Not had any hassle with mines yet but I know I will at some point. Quote Link to post Share on other sites
mikey4410 Posted April 30, 2015 Share Posted April 30, 2015 my side exit is 98db static and 92 or lower on a driveby at 10 metres. Quote Link to post Share on other sites
_shaun_ Posted April 30, 2015 Share Posted April 30, 2015 I've had a few pulls for my exhaust it comes in at 98dbs I argu the toss it's a grey import so the noise limit should be 99db. one got the hump pretty badly and said it didn't matter so I asked for a traffic officer he got even more pissed of and traffic officer came down explained why I belive mine to be legal and the traffic officer said he had to agree with me since am From a small wee town i asked if it was possible for them to notify the local police that I had been spoken to and my exhuast was legal to due to the type of car I had and the guy said provided his boss was happy he would do so. That was the last Time I got pulled for mine we recently had vosa down doing inspections with the help of the police and I drop straight past and they didn't bat an eye lid.If it's a jap import you can argu the toss as its a very grey area. Most police won't no what there taking about with regards to them so just be polite and speak with confidence and most of them will listen to yourside of the story. If it is a uk spec then your pretty fucked and at the mercy of the police man rules are very clearly written you can not alter your exhaust in anyway that makes it louder or have higher emissions than its type approval Quote Link to post Share on other sites
_shaun_ Posted April 30, 2015 Share Posted April 30, 2015 I've had a few pulls for my exhaust it comes in at 98dbs I argu the toss it's a grey import so the noise limit should be 99db. one got the hump pretty badly and said it didn't matter so I asked for a traffic officer he got even more pissed of and traffic officer came down explained why I belive mine to be legal and the traffic officer said he had to agree with me since am From a small wee town i asked if it was possible for them to notify the local police that I had been spoken to and my exhuast was legal to due to the type of car I had and the guy said provided his boss was happy he would do so. That was the last Time I got pulled for mine we recently had vosa down doing inspections with the help of the police and I drop straight past and they didn't bat an eye lid.If it's a jap import you can argu the toss as its a very grey area. Most police won't no what there taking about with regards to them so just be polite and speak with confidence and most of them will listen to yourside of the story. If it is a uk spec then your pretty fucked and at the mercy of the police man rules are very clearly written you can not alter your exhaust in anyway that makes it louder or have higher emissions than its type approval Quote Link to post Share on other sites
MARC MOSS Posted April 30, 2015 Share Posted April 30, 2015 Not as much. The gasses out of a side exhaust are way hotter than they are on the back of the car. And this hot air shooting out the side may burn other peoples cars paint. But well I always go for the worst case. It's just my common sense for others and my sense for aesthetics tell me a rear exhaust is better. Otherwise all manufacturers had side exhausts on their cars.Shit man I was having a day feeling old at 39 now after seeing this I feel 20 again lol Quote Link to post Share on other sites
ianmcintoshi Posted April 30, 2015 Share Posted April 30, 2015 Well, I know it adds power but the cost is more pollution. With a 200cell cat you'd have same power without pollution. Just my opinion.But I really hate cars that are too loud even in low rpm and point their exhausts to the sides. Could damage other cars bodywork in worst case.But well, I'm German, my father was a policeman and my mother a high official so I may be a bit strict in that. I don't like adding pollution without need and because I grew up near a main street I really really hate loud cars, especially in the night. Also around hereall loud cars are VWs and I hate VW. I take it you drive a prius then mate? Quote Link to post Share on other sites
Gainzy Posted April 30, 2015 Share Posted April 30, 2015 Would front exits not just increase back pressure due to fluctuation decreasing throttle response and just create more heat and noise than anything else, I suppose a decent map could stop this? They seem pretty cool but I like my long shiny one's Quote Link to post Share on other sites
_shaun_ Posted April 30, 2015 Share Posted April 30, 2015 Would front exits not just increase back pressure due to fluctuation decreasing throttle response and just create more heat and noise than anything else, I suppose a decent map could stop this? They seem pretty cool but I like my long shiny one's its really minimal but should increase spool. you bascily want the exhaust gasses out of the exhaust as fast as possible to make space for the new gases. as the gasses cool down they slow down aswell. i could be wrong but as i understand it its not really back pressure presure you dont want its exhaust gas velocity you want to maintain. back presure is just a bi-product to try explain althought it really applys to n/as more the exhaust gas velocity creates a slight vacuum to help almost suck out the exhaust gasses from the combtion chamber. think of it like pulling your hand through the water in the bath as your hand pushes though the water the water has to rush to the back of your hand to fill the void your hand has just created the faster your hand moves the bigger the vaccum created to fill the void behind your hand. obviusly theres alot more to it than that but as a rule of thumb for an n/a you want a correctly sized exhaust ( not to big not to small) and try keep a decent heat into to keep the gasses flowing nicely again not to hot not to cold. on a turbo the systems already so pressurised you just want the biggest shortest exhaust possible so a 3" side exit is better than a 3" rear exit. try keep some decent heat into it to keep things moving nicely and heat wrapping it keeps the temps down and likely hood of flameage up so its a win win really. someone thats studyed motorsport engeering or something may totaly correct me but thats what my research has ld me to believe Quote Link to post Share on other sites
RobSR Posted April 30, 2015 Share Posted April 30, 2015 The less back pressure the better especially on turbo charged cars. Side exits work well, better spool and lower egt's if they are a tapered design too. As shaun explained with n/a exhausts you don't need back pressure its a myth. Its about getting the 'harmonics' correct. Think about a pipe organ in a church as an example, feck off massive pipes, but when tuned correctly make a very precise sound. Same with an exhaust on an N/a you can have large bore, but it needs to be designed correctly to be effective. Quote Link to post Share on other sites
Gainzy Posted May 1, 2015 Share Posted May 1, 2015 Good info guys front exits can't be all that bad then a plumbed in ewg would sound mental Quote Link to post Share on other sites
FrozenJakalope Posted May 2, 2015 Share Posted May 2, 2015 So then, to follow up on the harmonics thing, you'd want an exhaust with a volume that's equal to a multiple of the displacement of the engine.A few basic assumptions being that the exhaust runs more or less straight, an EP91 is about 3.7m long and the exhaust starts about 30cm back from the bumper but also drops about 30cm to get under the block.So L=3.7, V=pi*L*r^2 and you want V to be a multiple of 1.332.Solve for R gives R^2=V/(pi*L)Start plugging in multiples of 1.332:1.332*1 would give an exhaust diameter of 3.02in. So a 3.02in pipe running the length of the car with decat would have enough capacity to expel 4 cylinders worth of gas per cycle with no drop in pressure (as long as it's all timed up right etc). Course, this could be a lot more precise if I actually went out and measured the exhaust, but should be rightish. Conclusion, 3in straight pipe on a N/A would do nicely Quote Link to post Share on other sites
Ollieh17 Posted May 2, 2015 Share Posted May 2, 2015 1 day and havent been pulled yet haha Quote Link to post Share on other sites
5e colin Posted May 2, 2015 Share Posted May 2, 2015 So then, to follow up on the harmonics thing, you'd want an exhaust with a volume that's equal to a multiple of the displacement of the engine.A few basic assumptions being that the exhaust runs more or less straight, an EP91 is about 3.7m long and the exhaust starts about 30cm back from the bumper but also drops about 30cm to get under the block.So L=3.7, V=pi*L*r^2 and you want V to be a multiple of 1.332.Solve for R gives R^2=V/(pi*L)Start plugging in multiples of 1.332:1.332*1 would give an exhaust diameter of 3.02in.So a 3.02in pipe running the length of the car with decat would have enough capacity to expel 4 cylinders worth of gas per cycle with no drop in pressure (as long as it's all timed up right etc).Course, this could be a lot more precise if I actually went out and measured the exhaust, but should be rightish.Conclusion, 3in straight pipe on a N/A would do nicely jeeeez u related to einstein ha ha u lost me there dude best for turbo is having no exhaust ha ha really Quote Link to post Share on other sites
FrozenJakalope Posted May 2, 2015 Share Posted May 2, 2015 jeeeez u related to einstein ha ha u lost me there dude best for turbo is having no exhaust ha ha really Connect it straight to the heater ducts in winter, car would be toasty in no time with literally no downside whatsoever! Quote Link to post Share on other sites
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