69 N.O.X. RATT

I just put the Delta series Flow Masters on my 580-590 solid roller cammed 454 and they sound wicked at idle, but resonate terrible into the rpm range a little. Would a crossover help, if so where should I instal it. :chevy

PRNDL

Yeah, you should "cross over" to 50 series!! :lol: :lol: :lol: :lol:

sorry, couldnt help myself. I have the 50 series and like the sound, except when I overrev the engine and shift sloppy I can get a nasty raspy sound. I also have a cross pipe kit (from Summit) waiting to go in. The only easy place I can see to install will be right behind the crossmember. I think that is where most end up installing a simple cross (H) pipe. MJ

zwede

Flowmasters drone. I used to have the 50 series delta flow behind my 454 and hated them. I got headaches from the drone after about 15 minutes of driving.

Switched to walker quietflow and all is well.

Alwyn678

Yes the Crossover should help...it mellowed mine out quite a bit...

mountainmotor

Zwede,
You have spent more time and effort looking into and changing mufflers than anyone here I think.What is your opinion toward the use of a resonator in each pipe before the muffler somewhere to mellow the sound and drone if the 40's without killing power?

zwede

It's an interesting thought. I think the 40's may just be loud enough to where no resonator could do much, though. Maybe a 50's delta flow would be a better candidate.

I tried resonators, but I used regular glasspacks (dynomax race magnums) as resonators. I'm currently running these with the quietflows with no resonance at all, and what I think is a nice noise level. The car is not quiet by any means. Still sounds like a vette.

I did try the resonators (dynomax bullets) and flow 50's and the drone was still there. All the glasspacks did was lower the overall noise level, but didn't change the drone. Maybe if I had used real resonators I would have had more success.

Another thing is that the resonance issue and total noise level varies depending on the engine size, whether headers are used and if you have cat(s) or not. On a late C3 with single cat and no headers, the flowmaster 40 may not be loud at all.

75rat

69 N.O.X. RATT, I put Flowmaster 50 series behind my big block and they sounded exactly as you describe....I did NOT like them. Talked to the Flowmaster people and put an "H" pipe behind the crossmember as they suggested. The difference was night and day, it mellowed out the tone and got rid of the resonating....I like them much better now!

Noel Carboni

Ditto on the crossover just behind the crossmember. I have one there, just in front of two cats, and my Flowmasters sound nice and mellow. That's not to say it doesn't shake windows, but it doesn't drone. Chevy Thunder! :D

I'm ashamed to say it was so long ago that I bought these mufflers that I don't remember at all what series they are; they are fairly short 2 1/2" units and have two chambers, I believe.

I'll be reading all I can here about Flowmasters because I'm looking to rework my entire exhaust system in 3" mandrel-bent pipe soon.

-Noel

norvalwilhelm

I think it helps. I put mine just behind the transmission crossmember. I went 3 inch but I thing it could be smaller. One pipe size smaller then the main pipes.

69 N.O.X. RATT

Thanks, I will try the H pipe idea, and report on the effects.