das76

Hey folks,

I'm working on getting my new to me '91 Turbo sorted (driver car, 99,000kms). One of those involves replacing some or all of the, what I believe to be, Billy Boat system, but I’m not 100% sure. The biggest issue is the drone between 2000 and 3000 RPM is, quite honestly, brutal. I wouldn't want to do a road trip in it, and even driving around town it's annoying. Above 3000 it sounds great. It also gurgles a lot when I pull the foot off the gas. I wouldn't mind less - it's a bit much for me. Overall i wouldn't mind a quieter system - that's hard to capture here. Even taking videos to capture the drone doesn't do it justice.

Here are some pics of what I have underneath right now. I have an RoW car from Japan. (I'm not sure what the original looked like; i'm assuming it might have been different than some USA cars, since I can't see how the suitcase would fit in given the positioning of some of the pieces, but that's water under the bridge now anyways.)

I've read a bunch of the threads here, and have had a few DMs with some of you, but I thought I would throw this thread out there to see if there are any other options and opinions from the experts.

So far what I'm considering, based on feedback from here, is:
- Rarly8
- BurnsStainless
- FabSpeed

I think I have 2 options:
1. Replace just the muffler and exhaust tip, and the wastegate exhaust pipe/tip.
2. Replace the whole system

Any other systems I should be considering?

Obviously cost wise #1 will be cheaper, but is there any reason or benefit to replace the headers/heater box portions too? However it might be easier to sell a complete system?

Are there any other "while you're here you might has well do XYZ" things that can/should be done? (Yes I know that, especially with this crowd, this is a very loaded question - haha - but I value everyone's input and I'm learning a ton everyday)

Replace/upgrade the wastegate?

If any of you have pics of your current systems I'd love to see those (good learning opp!)

I don't need to worry about passing any emissions tests (sorry Greta )

As always, thanks for all the feedback!

Megatron-UK

I doubt the sound will be from any of the exhaust components pre-turbo. My guess is that it is that single box exhaust coming directly off the turbo. The standard setup has a cat running from the back of the turbo, into a single box silencer in the right hand of the engine (between engine and wheel well).

I'd guess that a longer system, post-turbo, would probably reduce the drone; that set up really only has what, a foot and a half of pipe after the turbo? My reccomendation would be a cat bypass/straight-through section after the turbo, into a standard or aftermarket silencer up in the standard mounting position on the right hand side. That extends the exhaust system to a good 4 feet or so, and I would guess will get rid of that droning sound. Various 'sportier' sounding final silencers are available from a small number of aftermarket brands.

Black_Hat

It looks like you have a Burns stainless steel silencer/ maybe Borla ? , with a way too bug inside diameter .no wonder you get droning.

get a quiet RarlyL8 Muffler Straight through

I also see the oil line going under the engine replacing the stock oil line that gets in the way of after market headers - this is a good thing

and a weld repair of the snout pipe that goes to the waste gate (make sure the waste gate is supported it is heavy) - be sure to check inside your heater boxes for cracks

Scott Dunavant

4" pipes causes massive drone. Like those diesel truck guys with very deep exhausts. I had a Monty muffler back in 1996 on a 930. Sounded great but drone was loud