Flowmaster 40 series Original flows vs Delta flows

In the next month or so I will be having my exhaust system redone. I want to dump in front of the axle and heard somewhere that the original flows are loud enough to give you a headache when dumped, but I like what I have heard of them from the outside. Haven't really heard the milder sounding delta flows except on Flowmaster's website from a 1990 Mustang. They seemed to lose a lot of the throaty growl that the originals have.

 

flowmaster 40 series

I have 40 series on my 71 Merc1 and they sound like a real muscle car. At about 40 miles per hour there is a little hum. However, I am still pleased.
My buddy who installed the mufflers put the 40 series mufflers under the rear seats/floor pan area. He added chromed exhaust tips that turn down like a 1986 Mustang GT.

 

I have 2 chamber 40 series Flows on my Mav, but I had them routed all the way to the back and tucked up behind the valence with turndowns. They are kind of hidden... Anyway, they sound really nice, but I know a guy who was running the same mufflers on his stang with turndowns right after the axel and it was really, really loud inside and out. The sound would just bounce between the ground, and the bottom of the car. My dad's 1990 5.0 Mustang has "American Thunder" Flows with Delta Flow technology, and it is mellower than mine. No throaty growl, like you said. The only problem I have with his is it has a pretty obnoxious drone at about 2000-2200 rpm. Other than that it sounds pretty good if you like it mellower. Hope this helps.
-Corbin

 

Sorry I just want to make sure we are talking about the same two mufflers, I am not very familiar with terminology like 2 chamber or three chamber, they dont mention that on flowmaster website. The ones I looked at were...

>Flowmaster 40 series The Original Flows
http://www.flowmastermufflers.com/web10/PDFs/40seriesO.pdf

and

>Flowmaster 40 series Delta Flows
http://www.flowmastermufflers.com/web10/PDFs/40seriesD.pdf

Both are Flowmaster 40 series mufflers,

Are the american thunders you mentioned another name for the flowmaster 40 series delta flows?

Just wondering if someone has heard both of these

Thanks for your patience, I just dont want to realize I made a mistake when its too late

 

Sorry about that, yes I have the "Original Flows" on my Mav, so everything I said about my car and my buddy's old Mustang are in reference to the original flows. The American Thunder ones I am talking about on my dad's car are two chamber (I am pretty sure), and have Delta flow. Every thing I said earlier still applies, but hopefully this will make more sense. Sorry about the confusion.
-Corbin

 

P.S. I can't guarantee that the American Thunder ones on my Dad's car are in fact the two chamber flows with Delta Flow, but they will be very similar if not the same. I would suggest emailing Flowmaster about the Delta Flows. If you want the original Flowmaster sound with a more aggressive tone get the "Original Flows" 2 chamber 40 series, but if the milder tone is what you prefer, get the Delta Flows. It quiets the mufflers down, but in the negative aspect, to me, it creates more of a loud drone inside the passenger compartment at around 2000 rpm.
-Corbin

 

Thanks for the info Corbin, I think I will get the Original flows. I want to avoid running my pipes over the axle to the rear and was concerned with just how much interior resonance (headsplitting?) I would have if they were dumped. Saw a picture of an interesting setup by '72 Comet GT (pic below) So I am tossing that idea around against just dumping them. Tough decision.


I also bought an X pipe for the setup. Are there any pics out there of X pipes installed on mavericks? Clearance probs?

 

You'll love the x-pipe. It totally changes the sound characteristics of the motor...makes it sound more like a 180 degree header above 5000 rpm than a traditional v8 with duals. It also quiets the entire system down which is another plus, as well as making a bit more power in the midrange. I ran "the original flows" on the street maverick for a long time...yes they were loud, and no I wouldn't do it again. Just too much noise for street driving, especially at highway speeds. I would go with a 50 series three-chamber delta-flow, supposedly, they're the quietest flows on the market. They're still "noticeable" though LOL. I ran them on the bracket maverick last year and I will have to say they were about as quiet as a racecar will ever be...in fact they were so quiet that I had to listen for the roller cam rather than the exhaust to make sure it was running! IMHO, go with the 50 series, an x-pipe, and no larger than 2 1/2" tubing and you'll be happy.

 

50 series flows

I went to the flowmaster site to listen to their sound clip of the 50 series, they sound a lot like the mufflers I just removed from my Mav. Ultraflow by Dynomax. I'm looking for the lower tone from the 40s. So the X pipe is noticeable huh? I can't wait Although that isn't the only thing i will be adding. I am taking this oppertunity to finally install the headers I bought 2 years ago, also installed a shift kit. Everything else will be the same...600cfm Edelbrock carb, performer RPM intake, mild cam from Schneider, full roller rockers, ported and polished stock 302 heads. I was very happy with the way it ran before, I only wish I had all this work finished at the start of the summer

 

I will have to add that the sound files on they Flowmaster site do not do them justice. They sound just like the original 40 series, only quieter and with very little interior resonance. They don't sound anything like a Dynomax...or any other muffler for that matter, they have the famous Flowmaster sound which everyone is after. Yes, X-pipes on 302s are great!

 

40 Flows

I just installed 40 series flows in my 70 and I agree with mavman, the resonance is well.. loud! I like it though. They were quiter than what I was running, thrush turbos and above 3000 rpm they sound great. I dumped them right in front of the rear axle with the muffler tucked under the rear seat rise. Scott

 

I have Flow Pro 3" system on my car right now . I dont recommend them . They are so loud I can't even think .

Ive had a few systems on my machine ( not Flowmasters ) and a crossover pipe or X pipe does tend to make your car quieter .

 

Funny this topic came up....

I had Flowmasters installed on my Mav a few weeks ago. They are the 40 series Delta flow. I have pipes that go over the axle and turndowns at the edge of the valance. They do sound real nice, and are not as loud as I thought they would be...but still just a tad more "obnoxious" then I would like. I have decided to have 50 series Delta Flows put in. The 40 series is a 2 chamber and the 50 is a 3 chamber. (I thought that I was getting a 3 chamber when they put these in, but that is another story ) I have been going back and forth about having them swapped out, because it does sound cool......but I think the biggest thing I want to cut down on is the drone at highway speeds. I want more of a driver than a race car at this point and I think the extra sound will prove to be irritating over the long haul.(especially to the wife )

The other thing I want to have done is an X-pipe or an H-pipe. As long as we are talking about it...does anyone out there have input about whether one is better than the other? I have heard that an X-pipe is better, but an H-pipe would be a helluva lot easier to put in...any thoughts?

Also, if ya got a picture of the H or X please post it!

 

X is easier to install, trust me. With an H pipe you'll have to remove the entire exhaust system several times to get it all welded up right. I made my own X out of 2 pieces of 90 degree u-bends, cut the outside edges of the bend off on each one, then welded them together and de-burred. Then had to simply put a little bend on the end of one to connect to the passenger side pipe, and welded it all up. Very easy install, sounds cool (kind of like an Indy V8 at higher engine speeds) and best of all, helps the midrange more than an H pipe does. I ran an H on my old maverick back before I added the turbo...and couldnt tell the difference, but when I put the X on my mustang, I could feel the difference at part-throttle. Seems to have a bit more torque, and seems to get better fuel mileage, FWIW. Good luck

 

While I have heard that X-pipes work better than H, I think it varies quite a bit by application.

Any Midas or custom exhaust shop can weld an H pipe for you in 15 minutes, they are not that difficult. H pipes are really there to balance the two sides, and don't effect flow in any great way. They usually just mellow out the tone a bit. X-Pipes effect flow.