What bore exhaust?

[smudge2011]

Hey people just wondering what bore exhaust most of you are running? Guess it depends what you want it for, performance or just a little purr

I am thinking & trying to save for a powerflow, as a guy i know works at my local dealer. He asked if I wanted 3 inch or 2 & half? Quoted me £300 cat back, is that good?

Is the standard exhaust 2 & half??

 

[willpr]

I think standard on an lc is 2 inch which most people change to a 2.5 inch system but if you are thinking of going BT at any time in the futcher Ur best off opting for a 3 inch system. Bigger bore better flow

 

[Klone]

as will said...

my milltek is 2.5, but im thinking of going for 300bhp+ so i will get a 3" turbo back.

 

[willpr]

Wish I would have gone 3 inch custom from start.2.5 inch miltek must have cost me over 800 billys

 

[skiddusmarkus]

2.5" will do over 400bhp and give better torque/spool than a larger bore which will just slow the exhaust gases down.You don't need 3" unless you have big power goals or back pressure issues.

 

[Richie1985]

2.5" will do over 400bhp and give better torque/spool than a larger bore which will just slow the exhaust gases down.You don't need 3" unless you have big power goals or back pressure issues.

So if the standard exhaust can handle 200bhp at 2" and a 2.5" exhaust can handle 400bhp, theoretically a 2.25" exhaust will be good enough for stage 2 on a LC? probs about 260bhp at a push?

Just I can get a 2.25" system for a very good price but not 100% sure if it can handle the power.

 

[skiddusmarkus]

Well, work out the area of the pipe(pye r squared).On the 2" pipe it will be 3.142 square inches.On a 2.25" pipe it will be just over 3.5" square and on a 2.5" pipe it will be just under 4" square.
Your 2.25" pipe should do it ok, but will limit you if you want to increase the boost further as its not really much of an increase over stock.If its a nice smooth pipe and all you want is 260bhp and its cheap its got to be worth a punt as you can always sell it on in the future and get a 2.5" one.Personally I'd go straight for the 2.5" though.

 

[cupra_r_ick]

i was under the impression that with a N/A car you didnt want a too big bore exhaust as it will slow the velocity therefore the scavenge effect of the exhaust/cylinders.
on a turbo car the same applies but only before the turbo, so in the mani, and anything after the turbo you want it as free flowing as possible ....... therfore 3" would be better ?

 

[Applemobile]

But bigger isn't nessiserily better flowing. Hot gasses move faster than cold gasses, and if you have a larger surface area the pipe and gasses will cool down. It's a case of finding a happy medium in the middle.

 

[cupra_r_ick]

stick one of http://cgi.ebay.co.uk/Universal-Turbo-Supercharger-Air-Intake-Fuel-Saver-Fan-/260598167494?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item3cacdc77c6 these in there

 

[Gulfstream]

Ive got 3" til after sportscat then original 2.5" pipes. 500+ bhp no problemos.

 

[Allan_84]

i have the milltek LCR catback 2,76"/70mm resonated with an ebay 3" downpipe with a big racing metal catalyst on my 180cupra, and i love the sound.