V8 Exhaust

[Sox]

Originally Posted by GR8WITE

Got no drone out of my 2.5" twin, I put a twin 2.5" on thinking of the future mods I will do so I don't have to replace the exhaust twice because decent twin setups from extractors back cost a lot of $$$$

Your're lucky, many dual 2.5" systems drone to buggery.
Dual 2.25" pipes actually flow over 900cfm.
Considering a 70mm T/B flows approx 700cfm, the dual 2.25 pipes are actually way over the ~75% intake to exhaust ratio required for good performance.

A 5L even revving to 8000rpm only requires 700cfm of intake, and that's based on 100%VE.

In other words, a dual 2.25 system is more than capable of providing a restriction free exhaust for any N/A street car.

The muffler quality is far far more important in an exhaust system.

[Sox]

Originally Posted by Mont5.0

Hopeing to drop in on monday before work, just wondering what others thought.

I know what he'll say, bigger ain't always better.

[Windsor220]

Originally Posted by Sox

In other words, a dual 2.25 system is more than capable of providing a restriction free exhaust for any N/A street car.

The muffler quality is far far more important in an exhaust system.

Yeah i'll be keeping the twin 2.25 system on mine but just getting some better mufflers. The exhaust guy said going up to twin 2.5 would probably be too big and thats what I was thinking too considering there is some guys that put single 2.5 on their 5 litres.

[Fireblade]

I went with the twin 2.5" because later on down the track I want to go a stroker 347 and S/C, so possibly could still be too small. I had my future mods in mind when I did it.

[Mont5.0]

Originally Posted by Sox

I know what he'll say, bigger ain't always better.

PM you exactly what he said but yeah, Was quite happy with the quote and advice.

[MADED-6]

so u guys are saying get a twin 2.5inch exhaust i have a twin 2.5 into single 3inch and it used to drone oiff its head til i got another muffler put in it now its to dam quite lol.
mines stroked odviously as u may know so my question is would a twin 2.5inch system all the way be a benefit to me?
cheers josh.

[Sox]

Originally Posted by Mont5.0

PM you exactly what he said but yeah, Was quite happy with the quote and advice.

Excellent, fill us all in on how it is when done.

[Sox]

Originally Posted by MADED-6

so u guys are saying get a twin 2.5inch exhaust i have a twin 2.5 into single 3inch and it used to drone oiff its head til i got another muffler put in it now its to dam quite lol.
mines stroked odviously as u may know so my question is would a twin 2.5inch system all the way be a benefit to me?
cheers josh.

Either way will make no difference to performance. Both dual 2.5" and single 3" flow way more than you'll ever need this side of 8000rpm.

I prefer dual systems on a V8 because it allows dual mufflers. Dual mufflers will always outflow 1 muffler, all things being equal.
The pipe itself has little restriction on flow, and even dual 2.25" pipe is enough for most 5.6L.

[Mont5.0]

Cars booked in for this saturday. Leaving all existing set up- 220 headers, highflow cats, 21/2" two into 1 pipe. Having Rear muffler replaced and twin square chrome tips fitted. Will let you all know how it goes and sounds.

[BLACKAUXR8]

I think you'll regret going into two int0 one pipe. I have twin 2 1/2's and same as said above i have absolutley no drone in the car... and my pipes go to 3 inch after the diff (this was done cause it was the pipe we had when we made it) . The XR8's have twin pipes all the way to the rear standard.

[RG]

What diameter is the single pipe?

[Mont5.0]

21/2". lets remember this is on a 175kw Fairmont. Plus the exhaust bloke said the job done previously (headers etc.) was of decent work, and that he would not bother replacing the exhaust. So new rear muffler and tips it is.

[RG]

Originally Posted by Mont5.0

21/2". lets remember this is on a 175kw Fairmont.

People are going to flame you and say that it is too small, not me though. Whilst it won't make as much top end power as a twin or 3" system it will make more torque than them. Something more useful as a daily.

[Mont5.0]

exactly, Sox put me onto this bloke. He definetly knows what he is talking about, Bigger is not always better. Plus i dont required any extra attention.