Muffler Heat Shield

[Ghost001]

Hello,

I'm getting ready to install my new Flowmaster 50 Series Delta Flow 3-Chamber cat-back exhaust (part number 17203).

There is a warning notice (from Flowmaster) that came with the kit, saying to be sure to use any stock muffler heat shield, because the Flowmaster mufflers may get hotter than stock mufflers.

I was looking at my old mufflers, which are stock (with lots of holes in them!), and they seem to have some sort of heat shield strapped onto them, with metal straps.

Should I re-use the stock heat shields?

The Flowmasters seem to already have some sort of heat shield, spot welded on top of each one.

Or should I purchase the Flowmaster stainless steel heat shields (SummitRacing.com - part number FLO-51017), or get a couple of heat shields from a muffler shop?

EDIT: Here's a photo of the stock muffler, showing one of the straps that holds the stock heat shield on top of the muffler:

http://www.mustangmods.com/ims/u/2198/3911/115357.jpg

And here's the Flowmaster muffler. You can see what looks like some sort of heat shield, spot welded on top of the muffler.

http://www.mustangmods.com/ims/u/2198/3911/115358.jpg

 

[niklid05]

I really wouldnt worry about it. I bought two 5.0's, both had flows, and neither had heatshields on them.

 

[Ghost001]

I really wouldnt worry about it. I bought two 5.0's, both had flows, and neither had heatshields on them.

Thanks for the input.

By the way, I just added photos of the stock muffler and Flowmaster to my original post. Did your Flowmasters have heat shields, like the one shown in the Flowmaster photo?

 

[niklid05]

no, neither set of my flowmasters look like that.

 

[Ghost001]

no, neither set of my flowmasters look like that.

Hmmm. Maybe it's a new thing. Maybe someone's car caught fire or something, so they started welding heat shields on their mufflers, and issuing warnings.

Or, because it's the 50 series, and supposed to be quieter inside the car, I wonder if that top shield is a noise shield, rather than a heat shield. If it's just a noise shield, then maybe it doesn't do much to deflect or dissipate the heat (although it seems like it should, because it appears to be steel).

 

[Ghost001]

I just talked to a person at Flowmaster, and a muffler tech, and they both said that, if the Flowmaster already has a heat shield on it, then I don't need to add another heat shield.

The Flowmaster guy said that they throw that warning notice into every Flowmaster package, even when it's not necessary.

So it looks like I'm good to go, I guess.

 

[Darkwriter77]

You'd probably be better off putting some kind of sound/heat insulation on the underbody of the car, itself, than you would by putting it on the mufflers. Strapping a shield onto the muffler is likely to trap moisture and road salt between the shield/insulation and the muffler, and thereby rust those things out a lot faster (more so than Flowmasters already tend to do, anyhow).

If you pull back the carpet, scrape out all that worthless factory insulation crap from the front and rear seats and center console, and then either lay down some Dynamat or those strips of roofing tar-type stuff someone in another thread mentioned the sell at Home Depot (thinking of going that route, myself), then you'll block any major heat from getting into the interior from the exhaust and driveline. Probably cost about the same or less than what Flowmaster would've wanted to charge you for their silly "shields," anyway.

FWIW, the metal "heat shields" that come tack-welded onto Flowmasters are pretty much worthless, but you don't really need 'em, anyhow. It's not like you're going to be catching fuel lines on fire or anything like that, if you don't.

 

[Ghost001]

Cool, thanks for the info, Darkwriter!

That gives me more confidence that my Stang won't burst into flames or something.

I like your suggestion of using Dynamat as a noise shield and heat shield, underneath the carpet.

 

[Darkwriter77]

Since I stripped out the insulation from mine to try to save that all-important 5 pounds or so of dead weight I'd been dragging around, I've sort of come to regret it. I'm getting mad amounts of heat and road noise in there, now - not an issue when you've got the windows down and you're cruising at 80 MPH, but it SUCKS when it's cold enough that your windows are rolled up and you have to crank up the radio to even hear it.

I really liked that one fella's idea with the Home Depot sound insulation trick. I'll track down that post and link it here, as I might be doing it, myself, pretty soon. (I'll find some other way to save those 5 pounds of weight, or just make up for it with more horses.)

 

[U2SLO450]

no heatshields on any of my cars, all flows

 

[Ghost001]

no heatshields on any of my cars, all flows

Cool, another data point! Thanks U2SLO450!

I'm now pretty confident that the spot-welded heat shields are more than enough.

By the way, I'm almost done with the passenger-side muffler and tailpipe installation. I just have to attach the band clamp. Then, I have to do the driver side, but that's easier. And both of the old mufflers and tailpipes are off. The passenger side looks like a good fit. I also like that the Flows supposedly fit with an MM PHB, because I'm planning on getting one of those. I had to take off work today, because the install, plus an aluminum driveshaft install, and installing shocks and quad shocks, has taken longer than I thought it would, of course, and this is my daily driver. I've been working all weekend on the shocks, quad shocks, driveshaft, and exhaust. Yes, I'm slow, I guess because I've never done any of these things, and also because I'm very careful, and I take a lot of breaks. Luckily, I have flexible office hours.

 

[iwashmycar]

you'll be more than fine just boltin em up.

 

[Ghost001]

you'll be more than fine just boltin em up.

Thanks, Iwashmycar.

By the way, I got the install done, and the Flows sound really good. I had no idea what they would sound like. I got them because everyone said that they sound really good, especially the 2-chamber ones. I like the 3-chamber 50 series. Loud enough, but not too loud, for a guy with sensitive ears like me. And the quality of the sound is really nice, very old school.

The fit was a bit tight, because of my 18x9 rims with BFG 265/35/18 tires, and also because the driver side flow pipe seems to point slightly too far to the outside, but is seems okay.

Now I'm going to do something to add more stability to the pipes. I don't trust the band clamps by themselves, because the curved pipes caused the clamps to not fit well. Maybe I'll brace it with some metal straps, or put u-clamps on top of the band clamps, or maybe I'll just get the tailpipes welded on, if I'm sure that I've got them oriented correctly.