To gut or not to gut that is the question. 930 turbo muffler

[lendaddy]

Although I am making my own headers and muffler I am intrigued by the idea of gutting my factory unit for some testing... You know to gauge sound levels etc.. based on the amount of baffles obstructions and the like. Are there any pitfalls to this? Also, does the rear bumper really come off as easilly as it looks? I mean there appears to be like 4 bolts. And on a side note a special thanks goes out to rarelyl8 for the info he mailed me and pics of his car which is beautiful by the way! Thanks again guys.

[beepbeep]

I'm running gutted muffler, and i have no noise problems. A friend of mine is running just one straight-trough 3-inch short muffler directly after turbo, and it sounds great w/o being too noisy, so i recomend you to either:

1. Gut the muffler
2. Replace whole thing with straight-trough muffler and save 20 kilos/gain some HP on the way.

[beepbeep]

pic of mufflers:

[lendaddy]

You gotta be kidding? That thing loks like something my dads AC tractors use. Man if that works my options are wide open.

[jbailey930]

LD,
you're ahead of me on this, but I was leaning toward gutting the stock muffler too. I asked a couple of local engine builders on who could do my welding and these guys said run without the muffler. They reckoned the turbo wasn't as noisy as a NA 911. Now I am waiting for a Rennlister in Seattle who is doing some dyno runs with the j-pipe, stock muffler and none. I'll let you know what I hear from him.
Best

[dean]

Hi
I built my own SS muffler for my 930 motor. It was a bit of work. While I was welding and welding and welding, I was thinking that I must be on drugs. But now that it is done and is not too noisy I like it. I would do it again, but some have called me very stupid. Mine does resonate between 2700 and 2900 rpm.
Dean

[1bar]

The PO of my '77 930 (3.0 liter) gutted the muffler some time ago. It has a very deep throaty rumble at idle, and sounds pretty good except for a really bad resonance between 3000 - 3500 RPM. It get EXTREMELY loud between those points, maybe slightly less when decellerating, definitely worse with throttle.

I'd prefer a quiter car - I have a neighbor with NO sense of humor. He's already stormed over and chewed me out for "going too fast" - believe it or not, I was actually right at 25, the posted speed limit, but he thinks that's too fast for a 90 deg turn. Maybe in his SUV it is? I guess he feels it's his place to tell me so. Unfortunately, it's embarrasing to get the "stare of death" every time I go by his house, especially when I'm rattling the neighborhood windows.

Ayway, sorry for the digression. If you're going to gut the stock muffler, plan on doing some experiments to reduce the resonance problem - and give me any ideas that actually seem to work!

[Bill Douglas]

1Bar, I wish I could borrow your car. My neighbours need a good wake up call

I'm using a rusty muffler that sounds really nice but where I live I have to pass a goverment type inspection every six months and it is a nuisance putting layers of exhaust bog over the rust.

[RarlyL8]

Glad the schematics were useful to you.

I'm dealing with the same exhaust issue now as well. My motor pic was posted a few days ago with the 90 degree dump pipe. That is where I'm going to start. Several folks have told me that the only drawback to an open exaust is the burble you get when letting off the gas. I have a gutted muffler with a 4" single outlet the supposedly sounds about the same as the dump pipe. The stock exhaust is a last resort. I doubt that I'll use that option.
Try a dump pipe and see how you like it, add on from there.

[jbailey930]

Alright, I heard from the guy with 930 running dyno on GHL muffler, dump pipe and stock muffler. GHl yieled 6 more hp than dump pipe and 12 more than stock. Thought was needed back pressure throughout.

I have a complete GHL exhaust on order anyway. Anyone here wants to take a 930 euro and muffler off my hands, let me know.
best

[RarlyL8]

How much does a GHL cost? Is it worth the 6hp gained? How's the noise level and characteristics?

[jbailey930]

About $2600 for headers and muffler. Here's his site with mods and dyno numbers: http://www.my930.com/

Not sure about noise levels. I've got a 4 inch single out with the dump to the wastegate plugged. I've heard B&B with duals and they are rumbling louder than my current setup. We'll see but I am not concerned with too much noise just performance. Even in my current setup I love finding an on ramp with a jersey wall on the driver's side when nailing the throttle
Best