GTE Muffler Question

[Dave Payne]

Has anyone removed the fiberglass packing from the stock mufflers to improve the sound?

[Dave Payne]

Update: Cut the 6 mufflers open and removed a massive amount of tightly packed white colored fiberglass (hope it was not asbestos!). This is on a stock ANSA system. Will weld the mufflers back together w/o the packing and report how it sounds.

[tyang]

Hi Dave,

Good luck. Hopefully there won't be any gawdawful resonances!

Tom

[Dave Payne]

Hi Tom - Thanks for your comment. I was going to temporarily re-install the exhausts tomorrow with the cut open muffler shells taped back together with high temp duct tape to quickly check the sound level/quality, before I weld the muffler cases back together. Might need to reinstall SOME new fiberglass packing. I'm surprised that guys haven't tried this before? The reason is that it always seemed to me that the stock 250/330 exhaust systems are usually very quiet and somewhat disappointing.

[tyang]

Hi Dave,

Sound is a very subjective matter. After spending my previous career as an audio guy, I should know. I think the general consensus is Ferrari exhausts sound pretty good, with perhaps the 365GTC/4 being the best sounding. Tastes change through the years, and what might have been a pleasing sound may fall out of flavor with what we're accustomed to hearing today. There's a "Flowmaster Sound" that we hear all the time (commonly heard on a Mustang GT), and may be the standard reference people use in their "mind's ear" for comparison. Personally, this is not how every car should sound, just like not all Ferraris should sound like a C/4! Several years ago,

I did a controlled recording of three exhausts, a Stebro, a Timevalve, and a stock Ansa from three 330s. http://www.tomyang.net/cars/ferrari473.htm
The surprising thing was before the recording, I thought the Timevalve exhaust was too quiet, and the Stebro was too loud with a little too much rumble, but when I listened to the three recordings, I found the Stebro closer in sound to the Ansa. Now admittedly, the Ansa may have been a little rusty and leaking a little, but an interesting test.

I hope you get the sound you're looking for.

Tom

[Yale]

When I first got my car the Ansa on it could have also been used to strain spaghetti. Idling at a stop light was embarrassing it was so loud. However, at 5000 rpm in fourth, the hairs on your arm stood up and you felt like the $12,000 of (some) years Ferrari maintenance was well worth it. I knew though the amount of fumes were shortening my Ferrari driving years and I was going to go deaf even sooner then my job at a record company would suggest so I got a Timevalve exhaust. At first it was a bit too quite and I missed the hairy arm experience, but over the years, possibly as the packing burned off, it got louder and louder and for a while my Timevalve was fairly loud. Then Tom, riding in my car, noticed the exhaust was leaking. Timevalve made up new cans and I am back to it being quieter then I remember.

I don't think any of these three muffler manufacturers take any acoustic approach to their mufflers. It's just slap some material in there cause that is what's done. I have heard of Daytonna owners removing the packing from the rear cans only and maybe this is the way to go to get more ummpf in the sound. It would be great, with your roll of gaffers tape, if you did a series of sonic experiments. And you have six mufflers to experiment with. For me it would be great to have a quiet idle but a squall at 5000 rpm.

Please let us know. Best, Yale

[Dave Payne]

Picture of the cut open mufflers. These are ANSA.

[Rudy van Daalen Wetters]

Doesn't the exhaust system back presssure have an impact
on carburetor settings?

Rudy van Daalen Wetters
1963 GTE s/n 4001
1966 330 GT s/n 8705

[tyang]

Picture of the cut open mufflers. These are ANSA.

Hi Dave,

Your picture is not showing up, and I deleted the "*tp://michael2000%40cox.net@members.cox.net./muffler.jp*" so we won't have that pop up for a username and password to your account. This forum now allows your to upload the pictures to my server. just follow the prompts to inserting an image.

I look forward to seeing your "Frankenmufflers!"

Tom

[Jim Wickstead]

Dave,

When I purchased my GTC in '78 it came with an Abarth exhaust. It was pretty well used up, so I had Borla reporduce it in stainless. When we opened up the Abarth system, we noted there was no fiberglas packing. Nor could we find any indication there ever had been packing.

The new exhaust was made without packing and was quite successful, although It's difficult to compare exhaust sound at different times and by memory alone, my impression was the new exhaust was a little too competition sounding, and lacks some of "dignity" I would reserve for either a GTC or 2+2. Also, there was a slight resonance around 3,500 rpm.

I've often wondered what an original Abarth exhaust would have sounded like.

Jim

[Yale]

Doesn't the exhaust system back presssure have an impact
on carburetor settings?

Rudy van Daalen Wetters
1963 GTE s/n 4001
1966 330 GT s/n 8705

Tom has told me the Francois feels the stainless exhausts have not enough back pressure and as such tend to backfire more. But who knows. Yale

[Rudy van Daalen Wetters]

Yale,

I have heard the same comment about the stainless systems.
I have also read that it is a waste of time to set the carbs
on a Ferrari if the exhaust system is not in proper order.

Rudy van Daalen Wetters
1963 GTE s/n 4001
1966 330 GT s/n 8705

[Dave Payne]

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So maybe the picture will work this time. It worked before in preview but then I remember I had to enter a password. Sorry about that. I ended up installing the complete exhaust system with all the fiberglass removed from all six mufflers, and the muffler housings taped shut. It was basically headache loud, so I took everything back off and packed in about 1/2 as much fiberglass, and started welding the mufflers back shut. Finished three, will hopefully get the other side welded tomorrow. At this point I surrender, and whatever it sounds like this time is the way it's gonna be.

[Dave Payne]

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Picture of "taped" mufflers with no fiberglass.

[Dave Payne]

Update. I finished welding the mufflers all back together with about 75% as much new fiberglass stuffed inside. Not easy to do, by the way. To me the sound is much better, louder at idle and low RPM's than before, and I'm fairly happy with the result, but it was a lot of work.