Last year I received my 85 240 from Converse and I am trying to sort out some small details. One of the things that bothers me right now is the exhaust volume
is TOO loud.

The car setup is as follows:

.338 Ford V8 with a Comp Cam 35-304-8 Camshaft (similar to 270HR)
.Aluminum AFR Heads
.Single 3" exhaust to a 3" Cat Converter
.Spintech Camaro style rear muffler with (1) 3" Intake and (2) 2.5" Outputs to pipes.

The car sounds quite loud but the exhaust sound can get very tiring after 20-30 minutes of driving or sitting in traffic. I also want to keep the sleeper profile of the car.

I am assuming there are people out there with similar setups but I getting rather tired from the loudness of the exhaust.

I believe the Spintech muffler is quite free flowing but I need so something that is not as tiring.

I believe a Dynomax 17670 muffler could be one of the options.

Any suggestions or recommendations?

Are there any other options such as silencer tips?

Thanks

Mike

On my 745 with LT-1 V8 and 3-in single exhaust, I found a significant reduction in noise with downward-angled tips on the dual outlets of the rear Dynomax. The tips put the openings behind the rear bumper and "aim" the noise down.

I had earlier removed them to better hide the outlets (increase the stealth factor), but the noise increase was too much, especially after a while on the highway. The low rumble was turned into a harsh drone.
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Bob: son's XC70, dtr's '94-940, my 81GL, 83-DL, 89-745(V8) and 98-S90. Also 77-MGB and some old motorcycles.

I have a 347 in my 744. Dual 2.5" pipe. My original setup included 2 Spin-Tech Pro Street mufflers forward of the rear axle and 2-12" glass packs for resonators at the rear. The Spin-Tech's rusted within a year; replaced them w/ 2 more glass packs. Also running dual cats. I've run this set up from Dallas to KC and back...it isn't loud at all and best of all very quiet within the car. My point to all of this is simply that I was not impressed w/ the Spin-Techs...at all.
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When Volvos are outlawed, only outlaws will have Volvos!!

Is it a wagon? That will be hard. Sedan or wagon, put sound damping material (2 layers if possible) over the whole roof. That will help reduce some of the booming.

Additional muffler would be good.

Make sure you seal up openings such as around the shifter.

Greg
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My homepage:

Greg

The car is an 85 sedan. I had already installed dynomat in the roof , doors and floor.
The car actually has amazingly quiet with the original engine.

The problem is the current exhaust setup

I looked up that muffler you suggested. That's going to be loud as hell, too. It's tiny.

Just keep what you have now, and add the biggest thing you can fit in front of the axle.

Did you also line the whole trunk floor with dynomat? If you need to do more, try b-quiet or something like that, I think there are better values out there than Dynomat.
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My homepage:

I had gotten about 100 square feet of a product called B-Quiet(similar to Dynomat). I had also done the trunk.

The most tiring thing with my muffler is the drone. I found an article online comparing the quietest to loudest muffler for a 5.0 and the Spintech is 87db at idle where with no muffler the max is 91db and the quietest muffler (Borla XS) is about 80db. Only the MAC muffler seems to be a little bit more loud.

Sound Off in Quietest to Loudest (Decibels):

1.Borla XS, 80db at idle, 90db at 2,000 rpm, 110db at WOT.
2.Hooker Maxflow, 80db at idle, 90db at 2,000 rpm, 120db at WOT.
3.Magnaflow, 82db at idle, 91 at 2,000 rpm, 114db at WOT.
4.Flowmaster, 82db at idle, 93 at 2,000 rpm, 115db at WOT.
5.Flowtech Warlock, 83db at idle, 92 at 2,000 rpm, 112db at WOT.
6.Dynomax UltraFlo, 83db at idle, 94 at 2,000 rpm, 113db at WOT.
7.Borla XR1, 83db at idle, 96db at 2,000 rpm, 118db at WOT.
8.Bassani Street, 83db at idle, 96db at 2,000 rpm, 120db at WOT.
9.Edelbrock RPM, 84db at idle, 93db at 2,000 rpm, 118db at WOT.
10.Bassani Real Street, 84db at idle, 96db at 2,000 rpm, MAX. (120+db).
11.Flowtech Afterburner, 86db at idle, 94db at 2,000 rpm, 115db at WOT.
12.Flowtech Terminator, 86db at idle, 94db at 2,000 rpm, 119db at WOT.
13.Hooker Aerochamber, 87db at idle, 94db at 2,000 rpm, 114db at WOT.
14.SpinTech, 87db at idle, 97db at 2,000 rpm, 116db at WOT.
15.MAC, 87db at idle, 98db at 2,000 rpm, 119db at WOT.
16.No Muffler, 91db at idle, 103db at 2,000 rpm, MAX. (120+db).

That's some good info.

I know what you mean about the drone. My car is a wagon, and I haven't added any sound damping to the roof yet. Especially right at 70mph in 5th gear, it's something awful.

I had planned on redoing my exhaust and putting in 2 of the Borla mufflers. (On a dual 2.5" system). To do that, I first need to get rid of the external fuel pump and do a Wal-Bro in-tank.

And one of these days I'll do the roof.

Can you fit a Borla XS in front of the axle?

Greg
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My homepage:

Here is an update. I finally replaced the rear muffler with the Dynomax 17670. The muffler went in the same spot as the Spintech muffler and it was a tight fit. I was overall 6-inches longer than the old muffler (26 inches total length).

The car is now MUCH more enjoyable to drive and it about 50% less loud than with the old muffler. No more droning.

As a reminder the exhaust is a Single 3" to a Camaro style muffler that goes in the space of the original Volvo muffler. I am very happy that I did't go with a Dual 2.5" exhaust for the following reasons

1. Dual 2.5" vs Single 3" have very close flow
2. There is not very much space under the 240
3. Weight gain...

I have a 331 in my 740 wagon, and do regret going dual 2 1/2". The two pipes connect to a dual in/out Flowmaster SUV 50 series, and I didn't make it clear that I wanted room left for a possible second muffler, so the pipes run too close together to fit one in front of the axle.
He did a very nice job, though, and he had suggested single 3".
Since it's all stainless, it would be very expensive to change now, and I haven't been able to get through emissions since 2008 anyway, so it just sits in the garage. :( In fact, I have literally spent more on repairs to have this car sit (trying to pass emissions, and other problems)than I have to run my stock 760 every day.

If I could do it all over again, I would just go for a single mandrel bent 3", with two of the largest free flowing mufflers I could fit, since, being a street car, I don't operate at high rpm anyway.