Muffler Change

[Tom Veale]

We're changing out the mufflers on my '33. I've grown weary of the 1800 RPM drone. Also, one of them had started to rattle inside. When we took them off, we found essentially nothing but the perforated pipe inside. No glass. One of the perf pipes was loose, so that was the rattle. The design is pretty much straight through.

We're replacing them with a similar muffler but with better internal insulation. I'll report back on how they sound once they're clamped up and ready to test.

Have any of you attempted to install a cross-over pipe between the two sides? There's not a lot of convenient spots for such! If the new mufflers do the trick, then we won't mess with a cross-over.

Best regards, Tom

[68GT500MAN]

Tom,
Let us know what mufflers you are going to use (size and make). I might as well use the same from the get go.
Doug

[esff32]

Tom,

I am interested in what you come up with as well. I continue to blow the insulation out of mine every time I fire it up. My concern was fitment as it is pretty tight. I have seen other posts regarding the use of a Magnaflow, just not sure which model.

Evan

[Tom Veale]

Evan and Doug, I'll let you know our outcome. The muffler cans are just about the same size as the FFR originals. However, the inlet/outlet were not quite the same. The guy cut off the FFR inlet/outlets and welded them to the new cans. Then they fit up essentially the same as the originals. These are polished stainless, too.

I was surprised at the amount of "blueing" of the exhaust pipes and old mufflers. Maybe those long straights at Road America heat things up a bit more than I thought!


I'm going to stop by this afternoon and see if it's ready for a "Sound Check." Right now it's raining, so I hope it stops so I can drive it around a bit.

Tom

[esff32]

Thanks Tom, I appreciate the help.

Evan

[Tom Veale]

I did a quick "sound check" with the new mufflers. While not significantly different in size or design, the packing material inside the can is far more effective even than when the original muffers were installed. More mellow and less "tinny" sounding. However, this was mostly at idle since I couldn't drive the car.



The new mufflers inlets and outlets weren't quite the same as the old ones. So, the old inlets and outlets were cut off the old cans and re-used on the new cans. Fit-up was then pretty much the same as the original FFR parts.

Also, I mentioned the amount of 'blueing' of the exhaust pipe from the header to the muffler and on the muffler itself, here's a photo of that.


I'll post more information on the new parts after I've had a chance to drive the car and hear it at different RPMs and loads.

This was a little bit more fussing than I'd originally anticipated, but so far the results seem nice.

Tom

[myjones]

Tom,
I am interested in what you come up with as well. I continue to blow the insulation out of mine every time I fire it up. My concern was fitment as it is pretty tight. I have seen other posts regarding the use of a Magnaflow, just not sure which model.
Evan

I ended up choosing the Magnaflow 11255 for my 33. It was the largest body that would fit within the same cavity as the FF muffler did and had the inlet outlet sizes I wanted and the best offsets in those for my exhaust layout. It will still be loud enough but with a nice tone and IF I need more I will add a couple small resonators on the rear duals further back. I can't put those right at the back because of my rear fuel tank but it looks like they will fit in the risers just fore or aft of the 8.8
YRMV
DB

[erlihemi]

You guys aren't running 4.88 gears and straight 3" pipes??? Surely Road America begs for double overdrive and straight pipes!! Awesome pic Tom. When you find a can that passes the test we all will thank you for sharing.

[Jay Mann]

I installed Flowmaster 842442, I only had to shorten the outlet pipe a little and they slipped right in place.

[Tom Veale]

Re: Cross-over pipe...............

There really isn't any room for such a thing if it's going to be sized appropriately. Anything bigger than a soda straw would compromise ground clearance.

Best regards, Tom

[myjones]

Re: Cross-over pipe...............
There really isn't any room for such a thing if it's going to be sized appropriately. Anything bigger than a soda straw would compromise ground clearance.
Best regards, Tom

Tom
Can't recall if you have rear exit duals? but if so a crossover pipe would likely fit at the kick-ups to go over the 8.8. without hurting ground clearance.
I couldn't tell from the pics where you dumped your exhaust.
DB

[Tom Veale]

Hi DB, Yes, we considered putting a cross-over pipe downstream of the mufflers, too. I have the rear exhaust on my car. However, most of what I have read suggests the greatest benefit is to have the cross over or x-pipe upstream of the mufflers rather than downstream. These mufflers are quite a bit more mellow than the original cans. I'll post a part number later. A quick drive yesterday (sleeting outside!) shows the "drone" sound that used to be there between 1700 and 2000 RPM has gone elsewhere. That will make cruising at 55 to 65 a much quieter experience. It still barks pretty loudly at full throttle above 3000 rpm and that's fine. It was the part throttle sound right where I drive on two lane roads that grew wearing on my hearing.

More later once the weather improves again. Mother Nature apparently was delayed in her April Fools jokes. It snowed here in WI overnight!

Best regards, Tom

[myjones]

Hi DB, Yes, we considered putting a cross-over pipe downstream of the mufflers, too. I have the rear exhaust on my car. More later once the weather improves again. Mother Nature apparently was delayed in her April Fools jokes. It snowed here in WI overnight!
Best regards, Tom

82 here Sat 28 here Mon so we are bouncing around too. I just noticed a new vendor making custom socks for the hot side turbos and I think I will just have them make socks for my bigger mufflers and I can buy the socks for the pipes already. Between that and ceramacoat I don't think I'll even bother with the lizard skin for heat, I'll just do the sound deadener on the floors. The X's do work better where you still have both high and low pressure waves before a muffler but they will still disrupt and change the wave profile anywhere in the system.
Dale

[Tom Veale]

The new mufflers we installed on my '33 are made by SLP Performance. Available through Summit Racing with Mfg Part Number 31065. 304 Stainless Steel and polished and embossed with the SLP logo. They're straight through design similar to the original FFRs so any tuning you've done with the FFR mufflers should not change very much with these for replacements. Dimensions are 12.188" long Can x 18.188" overall with inlet and outlet x 4.5" thick x 8" wide. Center inlet and offset outlet.

[esff32]

The new mufflers we installed on my '33 are made by SLP Performance. Available through Summit Racing with Mfg Part Number 31065. 304 Stainless Steel and polished and embossed with the SLP logo. They're straight through design similar to the original FFRs so any tuning you've done with the FFR mufflers should not change very much with these for replacements. Dimensions are 12.188" long Can x 18.188" overall with inlet and outlet x 4.5" thick x 8" wide. Center inlet and offset outlet.

How do they sound Tom? I'm really tired of the sound of the supplied mufflers and looking for a more muscle car sound. Mine sounds really loud when you give her a little love from the right pedal but not in a good way. I was thinking about Magnaflow but am open to something else.

Evan

[Tom Veale]

How do they sound Tom? Evan

At idle these are a bit quieter and more mellow. The 1800 rpm drone moved to some other range where I'm not usually driving. Full throttle above 3000 rpm still has happy loudness, but cruising at 1600 to 2200 rpm is relatively quiet.

Part throttle while accelerating is far more of a rumble than a scream. Nobody's going to mistake it for a Toyota Prius, but it's quite livable. I still have my ear plugs hanging on the headlight switch, but I've not driven it for a half hour or more at speed to see what that's like. I have noticed wind noise a bit more, so I think that's because the car is quieter overall. I'll report some more after I've taken a short trip with it.

BTW, the cost for two mufflers from Summit was about $220 total.

Best regards, Tom

[geoffav]

I've had good luck with the SLP and Magnaflow parts. I tried the SLP Loudmouth catback on my 04 Mach1. It was too loud. Next I went with the mufflers Tom has, Power-Flo (also SLP) they were too tame. Then I went with the Loudmouth IIs, perfect for the Mach1. The Mach1 still had cats so that might have made the Power-flo the perfect match. I was convinced the Magnaflows would be my choice but I had forgotten how good the SLP stuff sounded. Confused again.

[esff32]

At idle these are a bit quieter and more mellow. The 1800 rpm drone moved to some other range where I'm not usually driving. Full throttle above 3000 rpm still has happy loudness, but cruising at 1600 to 2200 rpm is relatively quiet.

Part throttle while accelerating is far more of a rumble than a scream. Nobody's going to mistake it for a Toyota Prius, but it's quite livable. I still have my ear plugs hanging on the headlight switch, but I've not driven it for a half hour or more at speed to see what that's like. I have noticed wind noise a bit more, so I think that's because the car is quieter overall. I'll report some more after I've taken a short trip with it.

BTW, the cost for two mufflers from Summit was about $220 total.

Best regards, Tom

Thanks for the rundown Tom. Now I need to make a decision if I'm going to do this before the show or not.

Thanks for the additional help Geoff, I'm as confused as you. Haha

[Tom Veale]

Hi Evan, Finally a weekend with civil weather and some time to take 007 out for a drive! I'm quite pleased with the sound of these new mufflers. Under part or full throttle the old mufflers had a far more 'tinny' sound. These SLP Performance units are far more mellow. My wife says she can still tell when I pull into the drive and park in the garage, so they're not exactly silent. But they are far more livable than the old ones.

Today I managed to get about 20 miles of mixed driving in and am quite pleased. If it's nice tomorrow I will probably get it out again and do some highway cruising to see what I think at speeds higher than 50 or 60.

It's nice just to have it out and wear sun glasses for a reason other than snow glare!

Best regards, Tom

[esff32]

Thanks for the update Tom. I will eventually swap the supplied mufflers out but for now I am running a turn down at the muffler. It made a significant difference in the overall sound. It was still a bit loud driving to and from HB but a lot of that probably was due to wind noise. I'm happy with the sound for now. Onward to more pressing items on the list like roll bars, considering I find myself unable to control myself with the right pedal.

Thanks again Tom,

Evan