Flowmaster cat back?

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tayto

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I put a complete flowmaster system on my sqaurebody. i didn't even install the supplied 16" mufflers and put 22" magnaflows on. it's is slightly louder than stock and minimal drone. it drones slightly off idle, but cruise is fine in town and on the highway. FWIW

BTW, the kit came with an H pipe, I tried with out and then with. The H pipe definitely took a lot of the ear piercing "loudness" out. I also think H is quieter than an X system from my experience.
 
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slovcan

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Update:

I ordered the Flowmaster 17224 - American Thunder Stainless Cat-Back Exhaust System. It seems to be not so common and needs to be made/put together before shipping to the Canadian seller who sends it on to me. Could be another 4-6 weeks before I see it.

After all the replies here, I figured this will probably not be any louder than the Gibson CFT Superflow (the quietest Gibson) https://gibsonperformance.com/i-227...enter-dual-oval-muffler-stainless-55189s.html . The Gibson would likely have to be a shop install for me as there needed to be some adapting of pipe sizes (2.75">2.5" inlets, offset pipe for the narrower dual inlet center-center spacing, 3">2.75" outlet) or some dicking around with adapters myself.

This comes with the 50 Series Big Block stainless muffler which is supposed to be their quietest. Being stainless I'm hoping for 10+ years life. The original lasted 24 years now and is only just starting to show signs of age. She's never been a daily driver. However, I will lose the original stainless tail pipe as the Flowmaster one is aluminized steel. If that doesn't last 10+ years, so be it.

I'll report back after I install it. Thanks for all your advice.

Glenn
 

slovcan

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Well, back to the drawing board. Looks like it will be another 2 months before Flowmaster makes my muffler & tailpipe. I cancelled the order and am looking at Plan B's and C's. I also discovered that the bit about the muffler being stainless may have been a mistake or is no longer stainless - now says aluminized.
 

1997

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wow, that sucks, ya pretty sure it wasn't SS in that kit.
where are you ordering from, a CDN or US vendor?
are you stuck on Flowmaster? any good exhaust shops locally?

definitly not a complicated build for an exhaust shop if you trust them, imo.....
 

slovcan

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wow, that sucks, ya pretty sure it wasn't SS in that kit.
where are you ordering from, a CDN or US vendor?
are you stuck on Flowmaster? any good exhaust shops locally?

definitly not a complicated build for an exhaust shop if you trust them, imo.....

I have to order from a Canadian place. Flowmaster will ship free to the USA, but it'll cost close to $200 CAD to get it sent from a friend in Maine to up to me. Buying here gets me free shipping here, but availability is at Flowmaster's mercy.

Not stuck on them, but they have the correct 6" inlet center to center spacing to bolt up to the original pipes. The others I looked at like Magnaflow are too narrow. I wanted to do it myself without welding.

There is another option, but it could be a bit tricky. That's a Flowmaster 50 series big block that is dual 3" inlets and single 3.5" offset outlet. It could change the angle of the tailpipe enough to interfere with the shock or spare tire. Plus, I'd have to neck it down from 3.5" to 2.75" (a bit over 2.5" ID of the stock tailpipe). I'm going to see what it'll cost to get a 3" or 3.5" tailpipe made at a shop here.
 

tayto

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Summit racing does free shipping to Canada on orders over $300 USD. My kit was shipped with incorrect pieces. Took a few months to get it back in Spring/Early. I just waited 8 months to get some OTC jackstands!

 

slovcan

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Summit racing does free shipping to Canada on orders over $300 USD. My kit was shipped with incorrect pieces. Took a few months to get it back in Spring/Early. I just waited 8 months to get some OTC jackstands!


Thanks 1997. I didn't know that.
 

1997

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Thanks 1997. I didn't know that.

neither did I, :)
tayto posted summit and free shipping to CDN on orders over $300 USD.

Summit racing does free shipping to Canada on orders over $300 USD. My kit was shipped with incorrect pieces. Took a few months to get it back in Spring/Early. I just waited 8 months to get some OTC jackstands!

 

slovcan

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OK, I ordered from truckpartsuperstore.ca . Great to deal with. I got the kit and over the past few days prepped everything. Today I cut out the original muffler and tailpipe and installed the Flowmaster.

Prep: I cleaned the muffler with mineral spirits and dried it. Then I scuffed the surface (Flowmaster's flat black paint) with 400 grit emery cloth. Then cleaned it again with mineral spirits and dried it. Then I sprayed 3 thin coats of VHT Flameproof header paint (Frank Enstein's suggestion) - first 2 coats about 15-20 minutes apart, third coat the next morning.

I had to file the outside of the end of the tailpipe that fit INSIDE the muffler outlet. It was a fraction of a millimeter too big. Yeah the tailpipe goes inside the muffler outlet, BUT there is a bit of a shoulder inside there that the tailpipe butts up to so it is unrestricted.

This morning I cut off the muffler with a 7" cutoff disk on my mini grinder. I had to finish the outboard inlet pipe with a hacksaw about an inch (outlet first with a jack stand holding the muffler up). I used a G-Clamp to push the hanger rods out of the rubber hangers (flush on the first side) and a pry bar to pull them out the other side of the rubber.

Install: After grinding around the outside of the cut off inlet pipes I coated the outside of them with Permatex muffler cement as well as the front half of the Flowmaster tailpipe. I also sprayed some silicone lube on the hangers welded on the new tailpipe pieces. I had already put copper anti-seize on the clamp threads and had them positioned and snugged on the muffler inlets & outlet. The inlets were a real snug fit over the factory inlet pipes. No hammering required, but considerable wiggling and pushing. Great fit. It looks like Flowmaster squeezed the 3" inlets down to match the 2.75" OD of the factory pipes. Well done!

I didn't tighten any clamps until I had the pipes in the muffler. I used the supplied clamps. After I had the front tailpipe on and positioned for good clearance I tightened the inlet clamps. Then I put on the rear tailpipe - again with muffler cement. When I had them lined up I tightened the muffler outlet clamp. Then I lined up the rear tailpipe and held it in place on a jack stand and tightened that up. No leaks.

The muffler does sit a degree or 2 clockwise rotated (looking forward from the rear) when installed. This is normal and not noticeable. The stock one did, too, and nobody ever noticed.

The VHT process is to let it idle for 10 minutes, cool for 20, idle for 20, cool for another 20, then drive normally for a half hour. I went with idling for 15 minutes while checking the muffler temp, but it wouldn't go above 108*F, then cooling for 20, then idling for 20 and cooling for 20. Then I went for a half hour drive mostly at 50 km/h (30 mph) in second gear. I wanted to get the muffler temp up without it cooling from the airflow of driving faster. Then I let it idle for another 15-20 minutes while I had a beer with the guys.

Frank Enstein said to let it idle until the paint started to smoke the first time, but it just wouldn't get hot enough to smoke. Hopefully what I did was sufficient to cure the paint. This paint is more like powder than paint and NEEDS to be cured.

Oh yeah, I did spray over the scratches around the clamps after the first 15 minutes of idling.

It is a bit louder than stock, but deeper. Sounds nice, mellow. There is a slight drone at about 1600-1700 RPM under gentle acceleration. Not noticeable when cruising at that RPM. I'm sure it's louder on harder acceleration, but I can't judge how loud from inside the cab. Maybe next time it's warm and dry I'll open the windows for a listen. I gotta say, even the stock muffler and airbox was pretty loud under full throttle acceleration. I'm sure this is going to be a bit louder again. I do need to get on it to see if I can feel any difference over the stock one since I have the Black Bear basic tune. The freer flow is supposed to compliment that.

Last thing - tomorrow I going to put on the heatshield that came with the kit. The original muffler had one so maybe there's a reason even though I couldn't get the muffler hot today. Maybe in the middle of July it'll get hot.

Thanks for everyone's help.

Glenn
 
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