Twin Vs Single exhaust

[jasonrouse]

My mate asked me a question i could not answer.
He has a VY SS and doesnt know if he should get a single or a twin 2.5" exhaust system.

Is there any power benifits going for twin, and what is the sound like with a single.

Thanks

[team illucid]

single 2.5" will flow 2 small ... dual 2.5" will flow better ... I believe that single 3" is the smallest single pipe to go to with a single 3.5" better for the flow rate ...

Your best bet is to PM Thunder for advice ...

[cossmo]

Jason if you get an answer from Thunder can you post it here or ask him to. I think i am not the only one that would be interested in the answer to a very good question.

Cheers,
coSSmo
:)

[BLACK 346]

As pm'd to me by Thunder, twin 2.5 for power and
single 3.5 for the ultimate sound :)

[jasonrouse]

3.5" exhaust single. Wouldnt that be too big for a standard LS1?

[jasonrouse]

One other thing.
He has already gotten a quote for car back 2.5" single for $400.00

upgrading to 3" or 3.5" will it make much difference in price?

[spiritfc]

I would of thought anything bigger then 3" on a LS1 NA would be too big. A good exhaust has low backpressure and high velocity (Except for turbo or nitro cars).

[SSFreak]

Mine has a single 3" system. Sounds quite nice IMHO. Not too loud but has that lovely V8 rumble.

[One tonner]

I have had both a single 2-¾ system and a twin 2-½ inch system fitted to my Ute.
The single system made 210rwkw pre edit with Header, HF cats and 227rwkw post edit with good low down torque nice quite rumble.
The twin made 237rwkw with more top end power, but does not pull as well down low. Twin has a louder exhaust note and rumble.
If you fit a twin 2 ½ as a cats back only with standard manifolds and cats. It could sound a bit crappy, it may drone and pop and crackle when you back off. My twin sounded dreadful and droned until I fitted the Headers and high flow cats.
If you want the nice V8 rumble go Headers and high flow cats as well.
This will make the cars sound a lot better, on mine the drone almost disappeared, and the crackle on back off has gone completely.
If I had my time again I would fit a single 3-½ inch single. I think it offers the best of both worlds and fits better under a One Tonner than a twin.

[BLACK 346]

Damn, double post.

[BLACK 346]

I have had both a single 2-¾ system and a twin 2-½ inch system fitted to my Ute.
The single system made 210rwkw pre edit with Header, HF cats and 227rwkw post edit with good low down torque nice quite rumble.
The twin made 237rwkw with more top end power, but does not pull as well down low. Twin has a louder exhaust note and rumble.
If you fit a twin 2 ½ as a cats back only with standard manifolds and cats. It could sound a bit crappy, it may drone and pop and crackle when you back off. My twin sounded dreadful and droned until I fitted the Headers and high flow cats.
If you want the nice V8 rumble go Headers and high flow cats as well.
This will make the cars sound a lot better, on mine the drone almost disappeared, and the crackle on back off has gone completely.
If I had my time again I would fit a single 3-½ inch single. I think it offers the best of both worlds and fits better under a One Tonner than a twin.

Agree with you there. Haven't heard an LS1 yet that sounds good
with just a cat-back. They definitely sound better than stock,
but nowhere near as good as after the headers are fitted. Oh,
and just when your happy with the note, you hear a cammed
LS1 and it all starts again. Where does it all end.

As for a single 3.5 being to big for a standard LS1, wouldn't a twin
2.5 flow more than a single 3.5? Maybe I am wrong. I would
ask the expert (Thunder).

[Grif]

Ive gotten the Sureflo single 3 inch on my VX and i havent heard any LS1 with bolt-ons that is as rumbly from idle to 2000rpm and great low down torque as well! It doesnt have the sophisticated note as a twin system would but dam does the thing turn heads when just idling along streets. Just more rumble then anything. :D

Edit: Exluding a 3.5 from sureflo. ;)

[seldo]

................................

As for a single 3.5 being to big for a standard LS1, wouldn't a twin
2.5 flow more than a single 3.5? Maybe I am wrong. I would
ask the expert (Thunder).
A twin 2.5 has slightly more volume than a single 3.5. Two x 2.5" have a cross-section of 9.82 sqin vs 3.5 which is 9.62. Not a huge difference - it's only 2%, but still a difference..