View Full Version : People with 3" exhaust systems (& other questions)
Does your system knock against the beam?
I went to get a quote of a couple of exhaust fabricators and they said they won't do it because there is no space :confused: They will only do 2.5"
If I get a 2.5" system what sort of power is it good for?
And what sort of mods need to be done to a Corsa system to fit a Nova?
Cheers
phunkynova
20-07-10, 04:46 PM
you will loose power if the bore is to big you need some back pressure normally 2inch is good. if you don't believe me just look at race and rally car they don't use over sized exhaust because they know it's no good....it may look good sound good but kills power....so go for looks or power.
blue_peg_16v
20-07-10, 05:08 PM
2.5 will be fine i have the same on mine running phase 3, 3in would be overkill on a phase 2 and not needed untill your getting towards 450bhp imo
i only have 1 box too at the rear due to room in the tunnel plus with it being a saloon they could fit a bigger rear box my exhaust has never caught and i run a 90mm drop only problem is th handbrake cable rattles on it at times
craig green
20-07-10, 05:30 PM
If you insist on killing the handling with -100mm rear springs it probably would rub.
Rick Draper
20-07-10, 05:42 PM
I have been there and done it and done right it does not rub on the beam or the chassis even when lowered right down. Sounds like the place you are using has no faith in there own ability to do it.
Thing is they know what they're doing and an established business, probably just wants to make life easier for himself and there is no one else local :(
Thing is they know what they're doing and an established business, probably just wants to make life easier for himself and there is no one else local :(
Who is making the exhaust?
2.5 inch will be fine for a c20let with phase 2!
I'm running 2.25" on mine with phase 2. The standard LET downpipe is only 2.25" diameter anyway.
And what sort of mods need to be done to a Corsa system to fit a Nova?
Chucking in the bin. There not the same at all really.
A.a.s
Ah i see. They do make good exhausts!;) He tends to tell people what he'd like to do rather than what you want!
phunkynova
20-07-10, 07:30 PM
As I told you when did you last see a works turbo rally car with a well big boar exhaust they DO NOT WORK you need back pressure...power or looks.
Ah i see. They do make good exhausts!;) He tends to tell people what he'd like to do rather than what you want!
They do good exhaust but hes a bit of a dick and knows no one around this area does similar stuff so takes advantage of that
As I told you when did you last see a works turbo rally car with a well big boar exhaust they DO NOT WORK you need back pressure...power or looks.
I thought this whole 'back pressure' talk only applies to N/A
phunkynova
20-07-10, 08:15 PM
no even more so to turbo's.. my friend put a big boar on his turbo rally car and lost power so he went back to a all most standard one and the power came back..if big boar = power then all race/rally cars would run boy racer exhaust but they do not. :eek: when did you see a WRC run a exhaust the size of a bin if it meant more power they would find a way to do it.lol
no even more so to turbo's.. my friend put a big boar on his turbo rally car and lost power so he went back to a all most standard one and the power came back..if big boar = power then all race/rally cars would run boy racer exhaust but they do not. :eek:
Nonsense.
phunkynova
20-07-10, 08:22 PM
on what grounds is it nonsense ?
Rick Draper
20-07-10, 08:30 PM
no even more so to turbo's.. my friend put a big boar on his turbo rally car and lost power so he went back to a all most standard one and the power came back..if big boar = power then all race/rally cars would run boy racer exhaust but they do not. :eek: when did you see a WRC run a exhaust the size of a bin if it meant more power they would find a way to do it.lol
O dear o dear:cry:
Was the boar tasty when cooked?
backpressure strangles a turbo, slows the escape of exhaust gases, and in turn makes the turbo run less boost, therefore less power.
phunkynova
20-07-10, 08:35 PM
ok Mieran sorry if what i say dose not make sense ..Maybe you should ask a firm that dose turbo engine tuning, what they say is the best exhaust size for your car you will find most of them helpful and they should know what they are talking about. ;)
phunkynova
20-07-10, 08:41 PM
ok sorry not boar but bore you've got me there lol
2.5" exhaust will flow approx 257bhp,
2.75" bhp will flow around 310 bhp,
3" will flow nearly 370bhp.
http://www.mk5cortinaestate.co.uk/calculator5.php
hope that helps!
blue_peg_16v
20-07-10, 08:50 PM
well i know mine is more than 257bhp so guess those are a bit out
the engine was rr in the old vehicle with a 2.25 exhaust at 298bhp
djbrowney
20-07-10, 08:51 PM
next time you go to pod listen to the amount of screaming cars runing what you think in tyres is actually exhaust not being big enough bore :(
Buy the pipe from me, mock it up under the car and take it to a welding/fabrication and give them £20 to weld it up for you= simple
when did you see a WRC run a exhaust the size of a bin if it meant more power they would find a way to do it.lol
WRC cars are restricted to exhaust size for noise and power regulations!
2.5" exhaust will flow approx 257bhp,
2.75" bhp will flow around 310 bhp,
3" will flow nearly 370bhp.
http://www.mk5cortinaestate.co.uk/calculator5.php
hope that helps!
Add about 50bhp to all those figures and youre nearly there!;)
Buy the pipe from me, mock it up under the car and take it to a welding/fabrication and give them £20 to weld it up for you= simple
Job done!!
backpressure strangles a turbo, slows the escape of exhaust gases, and in turn makes the turbo run less boost, therefore less power.
This, backpressure is needed on NA engines due to the valve overlap to stop the inlet charge jumping straight out the exhaust, on a turbo they shouldn't be running any overlap and even if they did, a set of turbine blades in the middle of a 90 degree turn develops far more back pressure than any NA exhaust ever did.
MK were talking about turbos not NA
MattBrown
21-07-10, 12:45 PM
backpressure strangles a turbo, slows the escape of exhaust gases, and in turn makes the turbo run less boost, therefore less power.
Thank fck someone understands lol
2 strokes need back pressure, anything with valves doesnt really
*does need some* but very little.
Thank fck someone understands lol
2 strokes need back pressure, anything with valves doesnt really
*does need some* but very little.
n/a and turbo 4 stroke engines need varying amounts of back pressure depending on their application.....
the turbo itself creates backpressure because the blades are in the airflow, as does every restriction & i include bends as a restriction.
even a 'straight thru' racing pipe is length tuned to create backpressure low down to help to create some lower down torque. pulse tuning is almost a science on its own.
if you run a 4 stroke engine with no back pressure at all, it is gutless at anything other than full revs.... thus it is undriveable.
let_nova
21-07-10, 01:46 PM
I have been there and done it and done right it does not rub on the beam or the chassis even when lowered right down. Sounds like the place you are using has no faith in there own ability to do it.
i can back this man up as im running his old JP system on my nova. lowered 90mm with no knocking.
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