I've been noticing a sound coming from the motor that sounds just like an exhaust leak, that started after putting 50 series Flowmasters on. It is now very noticeable, but 2 different Ford dealers claim there is no leak, and one today claimed that since I put the different mufflers on, therefore making it more 'free-flowing', they said that it also changed the back-pressure and that it is causing the catalytic converters to make that sound.

Since there are so many Flowmaster owners here on this board, has anyone else had this problem? Is what the dealer said true about the cats making that sound as a result of free-flowing mufflers?

Thanks.

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Pritch

'00 Silver Lightning
-Flowmaster 50 series

'93 Taurus SHO
-BORLA
-High-flow Y-Pipe
-Superchip
-80mm MAF w/K&N

 

I just put a pair of 40 Delta flowmasters on last week and no problems. They should flow even more than the 50's so I don't think they would cause any problem with the catalytic converters. Man, if they did, Flowmaster would be in a world of hurt. My next door neighbor has a dual inlet/outlet on his regular F150 and no problems either. Did you try taking it to a good muffler shop and having them look at it? That's all they do day in and day out. Jeff

 

I just picked it up from the dealer and he said that since the Flowmasters flow better, there is less back-pressure, and therefore more flow through the cats, causing that sound. I told him that lots of people have put these mufflers on their L's and if they ALL had that 'exhaust leak' sound, nobody would buy them.

I'm no mechanic, but the idea that the converters making a whistling, ticking sound while accelerating JUST because the new mufflers are allowing more exhaust to be let out at a faster rate just doesn't make sense. I'm going back to the muffler guy tomorrow morning to get his opinion.

Anyone else have any thoughts?

 

Pritch, I am assuming you have 2 single inlet/outlet mufflers instead of the dual inlet/outlet. I know people have had problems with the dual, in fact, flowmaster recommended that they switch to 2 singles. Good luck. Jeff

 

Yeah I have 2 50-series mounted side by side. And thanks for the luck, I hope tomorrow I'll get this figured out so I can enjoy a true, Flowmaster sound instead of a Flowmaster/Exhaust Leak hybrid

 

Pritch,
Read my signature. Had the dual delta flow 50s for over 9,000 miles now. No problem, but not as loud as the 40s. However, nice sound when applying a little throttle. Can't hear nothing at WOT but the superchager and then you are really truckin' 70 to 80 mph down the highway... no resonance but a low rumble. The Delta Flow 50s have the approval for this 50 year old kid, but some like it louder.

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Ron B.
Kathleen, GA.
*Red 2000 Lightning
*ARE LSII
*Speed Liner (color matched)
*PSP Filter and Outer Ware
*Bear Tracker
*Valentine Radar Detector
*Dual Flow Masters Delta 50s
*Tinted Windows
*4 Pioneer TS-A6895 speakers
* Wet Okole seat covers

 

Thanks Ron. I am running the same mufflers. But did you begin to or do you still have any 'exhaust-leak' like sounds coming from the motor when you had the 50-series' installed?

That is what I am having trouble with and the dealer is saying that it's not a leak, but the cats making that sound as a result of less back-pressure. I just can't figure the cats making that sound just because more exhaust is going through then before. I think that the dealer is feeding me BS.

 

Pritch,
Is the sound coming from around the engine area or from the tail pipes? I had a 40 series installed in my R/T and it sounded like a jet taking off. Under acceleration, I would get a loud whooshing sound rather than the expected Flowmaster sound. Took it to the installer put a new muffler in and all was well. Apparently some baffle broke loose in the muffler.

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2000 Black Lightning, Snuglid
Custom Bed Carpet
Clear Corners, Lightning banner
Tinted Windows, Custom air intake
2" drop, VTech Taillight covers.
NLOC #377

See pics of '00BlackLightning at:
http://www.zing.com/album/?id=4294555843

 

When I'm inside the cab, it sounds like it's coming from the passenger side of the motor. But it also comes out the tailpipes. Dealer said it was the cats making the sound because of the change in backpressure from the Flowmasters. But when I asked him why its gotten louder over time, he didn't really have a good answer. I guess I will ride it out and see what happens, as I still believe that there is a leak someplace...

Then again, I'm now considering a complete exhaust system to get the sound I want. The Flowmasters don't sound all that good at WOT. Kinda sounds like a 'blatting'. Low rpm sounds fine.

 

Pritch,
AS I stated in my post I can't hear the flowmasters at WOT and seriously doubt anyone running a PSP filter kitt can either. The supercharger sounds like a Lear Jet spooling up.
I do not have any unusual sounds, but a deeper more throaty tone than experienced with the stock muffler. Nothing to run you out of the cab at 70-80mph.
Love to ride with the window down to hear the mild rumble. I do not know what type of sound you are experiencing, but I just have sweet mellow music until I go punch the throttle and bring the supercharger into play. I have no and never have had an exhaust leak with the flowmasters, but had them initially hit the drive shaft.... a little tweaking and now have a good 1 inch clearance.