View Full Version : Big exhausts
I was thinking while following an M3 or something - why do we all have enormous exhausts (well, those of us with aftermarket items) when 300bhp+ roads cars generally come with pissy little things as standard?? :confused:
Is there any benefit from having a drainpipe? If so, why dont hot motors have them fitted as standard?? :confused:
Most "hot" motors these days are N/A and there design to some degree does hinder there performance, Californian Legislation is the main reason, they have to be quite and environmentally friendly...
After market zorsts, do not :D
Big shiney zorsts on a serious performance car :smitten: :smitten:
Big shiney exhaust on a tiny hatchback :hurl:
Is it something to do with back pressure? :confused:
Thought Ive heard somewhere that N/A cars require some back pressure to perform their best, where as turbo cars dont?
The new Scoobies and Evos have large bore exhausts, just they have a pair of 2" tail pipes instead of one big 4" jobbie :)
Is it something to do with back pressure? :confused:
See thats what I thought, but surely then turbo cars would have fooking great tunnels (like our cars do) as standard - scoobs and evos have them now, but why not for the last 10 years?? Its not like an evo is an exercise in restraint is it?? :wack:
Also, why dont 911 turboes, Supes, GTO's, Integrales, Audi S3/4, Liners, and any other performance turbocharged cars have them as standard??
I think back pressure provodes low down torque and drivability. Thing is fast cars are fast cuz they're engines are amazing, their exhaust are small becuase they're quiet and the people inside like to listen to their CDs :)
See my point, this also covers ANY cars. It is also looked upon by the marketing people too....
Subarus and Evo's make more noise, but thats what the marketing people want, and aim for that market....
Nissan Obviously aim the 200 somewhere else :wack:
Most exhausts are made to meet legislations, maily californian ones, thus have to be quiet..
As you well know, take the cats off a 200 it pops flames, again, the cat is there to stop the free-er breathing which makes this happen.
Drifts_S14
01-07-2004, 14:39
Also, why dont 911 turboes, Supes, GTO's, Integrales, Audi S3/4, Liners, and any other performance turbocharged cars have them as standard??[/QUOTE]
because of the costs involved
Having a 36" tip on the end of a 3" bore is nothing more than show ... a 3" tip would achieve the same.
Its all looks.
If you look at the tuboed GT porsches on race tracks ... hey dont sport fecking great big ends ... purely becuae they achieve nothing but looks and noise.
But scientifically wasnt it JSF who was going on about the best configuration for a turbo car was a massive down pipe a amaller mid section and an even smaller end pipe so to speed up the flow of exaust gass and help drag it away from the turbo ?
If that was the case, and no offence to JSF, wouldnt HKS, Blitz, Nismo, Apex'i etc etc all have this configuraton :wack:
Also, why dont 911 turboes, Supes, GTO's, Integrales, Audi S3/4, Liners, and any other performance turbocharged cars have them as standard
because of the costs involved
911 turbo, Audi RS4/RS6, R34 Skylines are all 50k+ cars - I dont think the cost would affect these :)
And to Vez's "quietness" point - surely an Integrale, Skyline, Porsche GT3/RS and similar are racing cars - people want them to be noisy rather than luxury tourers. I just find it weird that by fitting a freeflow zorst and an air filter, you can make the car perform so much better, and so called "Extreme" performace cars dont come with this as standard equipment :confused:
Well the jap have tight restrictions on emissions so that probs explains skylines etc... TBH I think most people that buy porsches don't buy becuase they are good but because they carry status... I reckon its to do with noise and the market they're aiming for.
If that was the case, and no offence to JSF, wouldnt HKS, Blitz, Nismo, Apex'i etc etc all have this configuraton :wack:
I dunno ..... but I guess half of what HKS, Blitz etc do are marketed towards street buyers who want big tailpipes and shiney chrome.
Do the nissan cars that race proffessionally and in the big leagues still use pollished stainless steel HKS exausts or do they opt for lightweight one peice titanium units like other race cars ?? :confused: ... not really seen any full on Jap sports cars like you do Porsche / tvr etc so I dont know ?
kirkster
01-07-2004, 15:03
Also, why dont 911 turboes, Supes, GTO's, Integrales, Audi S3/4, Liners, and any other performance turbocharged cars have them as standard??
because of the costs involved
It costs more for a standard exhaust on some of those cars than it does to buy an aftermarket one mate.
Drifts_S14
01-07-2004, 15:05
Lets take the M3 for example - I reckon if you dyno'd the engine it would make well over what BMW lists as the horse power. I reckon they use restrictive pee-shooters as exhausts to tame the engine as it has too much horsepower for the 'average' driver.
Lets take the M3 for example - I reckon if you dyno'd the engine it would make well over what BMW lists as the horse power. I reckon they use restrictive pee-shooters as exhausts to tame the engine as it has too much horsepower for the 'average' driver.
It would be a lot easier doing that with the fuel map. You would ruin the cars characteristics and free revviness etc. :nod:
It would be similar to strangling pavarotti to make him quieter, rather than just moving him further away :wack:
Drifts_S14
01-07-2004, 15:12
It would be a lot easier doing that with the fuel map. You would ruin the cars characteristics and free revviness etc. :nod:
It would be similar to strangling pavarotti to make him quieter, rather than just moving him further away :wack:
I agree with you but who said anything about manufacturers being intelligent or doing things that make sense? :wack:
p.s wheres my lamba sensor :whip:
The thing is though, they dont make cars to be race cars, otherwise they would get rid of the leather interior, the soundproofing the matching head liners, the charcoal canisters the heated reclining seats, the 12 change CD player the Aircon.
These cars, all be it powerfull are still aimed at the rich yuppy that wants to be able to stick the cruise control on and drive quietly down the motorway whilst yappin on the phone and recieving a hand job of his boss's daughter.
Yeah they could stick a 5" tail pipe on it that would deafen the hell out of you on long journeys .... but with out the cats removed it isnt going make much overall difference in performance ... but I bet it would stop a few sales as daddies daughter complains that it is too loud and she cant hear her nail specialist on the phone :wack:
Lets take the M3 for example - I reckon if you dyno'd the engine it would make well over what BMW lists as the horse power. I reckon they use restrictive pee-shooters as exhausts to tame the engine as it has too much horsepower for the 'average' driver.
:no:
BMW M exhausts are very well designed. You can usually only get a couple of HP by changing them, and usually it just pushes the power up the rev range...
The e36 M3 and the M roadster have the same engine - the roadster makes 10BHP less because the exhaust has to have a kink in it to clear the axle...
SteveDunn
01-07-2004, 15:25
Perhaps if Nissan (as an example) were to introduce a fully modded car as a production car, then they'd put HKS/Blitz/etc out of business, and have lots of angry Japanese men running after them with big shiney (chromed) knives... Not something i'd want :p
SX Me Up
01-07-2004, 16:44
Another thing could be meeting regulations for the type of car. For example, performance Kei cars (car with maximum 660cc engine and maximum 64ps (Japan bhp system, about 62/63bhp) output stock, not neccessarily slow) pretty much always have horrible exhausts just to stay under the limit. The one on the Suzuki Cappuccino is horrible, causes back pressure stock! The one on the Daihatsu Mira Avanzato TR-XX has an enormous back box! Etc.
For Skylines and stuff it'll be to keep them from going over 280ps because the manufacturers have an agreement (I think it's fading away now mind) not to make production cars that go over it. I think it's to do with motorsport, make the touring cars more fair or something by not overdoing the road cars. In general though it's just to make the car quiet, we're performance type people but to be fair not everyone is, some people don't like their cars noisy. In Japan it's a rarity obviously but some old managers toodle around in R32 GT-R's utterly stock including exhaust and are satisfied.
On another note, an interesting fact about the power outputs of Japanese cars is that for sports cars most of the manufacturers lie and say it's lower than it is. The government don't actually have it checked so as long as they're not really pushing it and saying an R34 GT-R is 100ps or something they get away with it. The Avanzato TR-XX is meant to be more like 70-75ps in reality!!
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