ab1
Im getting an exhaust made up tomorrow for my b30 from the headers back. they are recommending the two headers into a single pipe running straight through with a muffler
Not sure if any one has experience with this but I was assuming given the port and mild cam a 2"1/4' pipe or 2and half " would be suitable.
@Rob you might have an idea?
Dauntless
I'd go with 2.5" and straight through mufflers.
I think the factory exhaust on those have fairly long secondaries, so I'd be trying to replicate that in something like 1.75" if possible.
Vee_Que
2.5 is a push, but drone becomes more of an issue then anything. The port isn't as important as the fact you have stock compression though.
Rob
Mine is running twin 2".
2 1/4 is probably good, 2 1/2 would be ok too. On a relatively stock engine that is huge.
ab1
2 1/4 sounds like a good balance. not keen for a drone its currently without the rear muffler and is just obnoxious
Does it make a difference sound or performance wise if its two pipes vs 1
Vee_Que
Robs car is supercharged and is LOUD. Last time I saw it. He towed it down. You've heard my 122 with one muffler and extractors, a, six even with lower compression should be louder due to the obvious factor of more capacity /cylinders.
But a good muffler can cut a lot of drone too.
ab1
How about the tone or note of a two pipe system over the two into one? yeah yours was loud but sounded good
Spac
Depends a lot on what you want/are willing to accept in terms of noise.
2.25" will be easier to keep quite than 2.5", and a lot easier to avoid droning at constant throttle, but will likely blunten throttle response slightly and possibly limit peak power.
I agree that long secondary pipes are a good idea. Shortening them by any significant amount is almost certain to cost torque, and possibly even top end power.
Dauntless
If noise is an issue, I think you'd fit a Falcon middle muffler under the rear of a Volvo pretty easily. The aftermarket ones are cheap, 2.5" pipe diameter, should flow more than enough, and seem to control drone very well when combined with a hotdog.
Slowbrick
I also think a 2.25" will produce more of a rasp instead of a drone compared to a 2.5" setup. Of course I could be talking shit.
ab1
Thanks for the advice guys. The exhaust guy is keeping the long secondarys and running them into a muffler and 2 1/4 from there. Should be an interesting sound
Spac
Should be alright. My old rally car had a stock system with a rear muffler delete.
Sounded great. Probably a bit loud for a daily, but you hear many that are much worse.
ab1
sounds like a Barra now ... they only put the muffler in not a resonator. would adding a resonator give it a more pure note?
Dauntless
It'll make it less raspy. What type/size muffler did they use?
ab1
idk if its raspy more boofy if you get what I mean
Slowbrick
What is going on with those welds? Holy hell.
Rob
Your muffler man needs welding lessons
ab1
it also drones horrifically and the previous system didnt and that had the rear muffler deleted...
Spac
Time for a new exhaust shop...
A long resonator would not hurt.
Do you know what type of muffler that is? As in, straight through, dogleg or baffled?
A straight through muffler by itself is almost certain to give a noisy, drony note. If you only have one muffler (without a turbo), then it sort of has to be a baffled one.
ab1
I'm actually not sure but yeah I don't know what they were thinking. I asked for a nice note with a bit of a crackle on upshift. I'm absolutely furious spending 400 to make it sound worse than it did before