Magnaflow versus Flowmaster ~ Showdown on the Dyno

comments to comments:

But there is some offset. On the offset inlet, it is lined up with a resonator tube thingy; center inlet is aimed right at the tube that goes into the next chamber. You don't think it would be even slightly quieter with the offset inlet?

I had an aluminized Flowmaster on my last truck. Ran it 14 years, never rusted out and sounded the same the day I sold it as the day I installed it. But I did live in a dry area and the engine (and exhaust) was always fully warmed up. But yeah, I'll go with stainless this time. No reason not to.

I had a turn-down on my last truck, only cuz it was cheap and simple. That was on a V6. It was loud. I like to hear my engine! But I will go with the full length on this.
Keep meaning to ask, at what point did you replace the factory tailpipe with 2 1/4"? Did you ever just replace the muffler and keep the stock tailpipe? I'm going with a 2 1/4" muffler so I want the tailpipe to also be 2 1/4". There is something bad about going to a larger diameter pipe. Well, maybe not bad. But I've always heard that with flow, it is much better to reduce diameter than increase.

and remember:
"One man's drone is another man's music" -Gaudenti

 

I could only guess as mine is center inlet and I don't believe trying another muffler for a subjective sound test would yield definitive results. Theoretically, yes. I don't know whether or not the real world difference would be perceivable.

Yeah, I read more than a few guys complaining about Flowmaster rustout, but I'm sure that cold, rain, snow, and salted roads figure heavily into the results.

You can keep your stock pipe for now and see how you like it. It can always be changed later.

The people who want more top end performance will naturally open up their exhausts. That top end gains means trading off some low end torque to get them. It's all a personal choice and to what purpose a truck is used.

Here's my timeline:

At first everything was stock... for only 6 days until I put on the header.

Then I tried an 18 inch Magnaflow with the stock pipe. Too much drone.

Then I ran the 22 inch Magnaflow with the stock pipe. Good.

Then I put on the 2.25" exhaust. Better.

Then last came the Flowmaster. Best.

So true!


Greg

 

Tooter, I have a 1.5hr drive to a dyno.................... how long should I let the truck cool down before I jump on the rollers?

Its 7sonly at buttonwillow

 

We open the hood and put the fan on while it's being hooked up to the dyno. So it's usually about 10 to 15 minutes cooling off. We also got superbly consistent charts by rolling on the throttle at very low rpms rather than suddenly stomping on it at higher rpms. On some of the runs we got the dyno to start recording at only 900 rpms.

As far as I'm concerned, the only really useful dyno information is the torque curve from 1,000 to 3,000 rpms. Everything else is just for show.

Greg

 

I would question why you want it to cool down? You want the data to be reflected at normal operating temps.

 

The engine doesn't actually get cold in that short time. It's to compensate for heat soak. Whenever you shut down the engine gets hotter than when it's running because the cooling system is not working. It also gets really hot during the run because the fan doesn't move as much air as when the truck is actually moving.



Greg

 

That part's understood, I just question that 10-15 minutes is really going to take much heat soak away stuck in a shop with only a fan? Unless you can unstrap it, take it outside in the shade and breeze and leave the hood open, I just can't see it making enough of a difference in heat in that itme period. Might even be better off leaving it running

 

The fan works good enough. A hot engine is ok, just not too hot.

Greg

 

I could go with an offset inlet, and then we can do a side-by-side comparison. Oh, no, that won't won't work. I won't be be getting the same tailpipe as yours. Never mind.

Good idea. Well, I am going to start with a 2 1/4" pipe cuz all the charts I see say that is the best size for our size/HP engine. Maybe I'll start with a turn-down and then add a tailpipe if it's too loud.

 

Yes, Flowmaster has the best (only?) anti-reversion muffler out there, but I'm talking about using valves that actually close when there is negative pressure in the chamber. Like a reed valve on a 2-stroke engine? Probably not something that is practical to do in a muffler . . .

 

That's an interesting idea, Dan... but think that a valve that actually closed would restrict the flow too much because I'm not certain that it could react fast enough for the number of pulses as well as the exhaust volume generated by a 4 cylinder engine.

Also reed valves are only used on the intakes of 2 cycle engines. They use reflected pulses in expansion chambers to scavenge exhaust gases.





I really like Flowmaster's idea of angled plates to use momentum of the exhaust gas to create low pressure areas that scavenge it.

And just another driving impression update... the more I've been driving with the Flowmaster, the more I like how it sounds.


Greg

 

Yeah, but I was thinking that many small valves would be light enough to respond to the exhaust pulses and, if there are enough, not restrict the flow? I was hoping you would start working on a prototype. You can call it the Tootmaster? Or the Flowtooter?

OK, OK, never mind. Just stay with the Flowmaster. For now . . .

 

Interesting, didn't know there was a dyno out there. But the important thing here is that we now know that the Batcave is 1.5 hr from Buttonwillow!

 

It's fun to explore possibilities in your mind, Dan.
The advantage Flowmaster has is their own fabrication and dyno facilities, so it's easy for them to try out new ideas. This is one of their newest... a laminar flow muffler. This is what the basic concept looks like...



Here's an end view of their Muffler...



Here's a mixture of laminar flow and chambered...



As you can see the possibilities are endless.


Greg

 

Yes, always fun to explore!

Some ancient history:

Below is a picture of one of Flowmaster's oldest mufflers. The story goes (from the guy who invented them): "When I first built my mufflers and started to advertise them, I traveled to many tracks and found that carrying mufflers to show people first hand, was a difficult task. After about my third trip doing this I went home and fitted a suitcase carry handle to the top of my samples. This made carrying them a breeze and soon I was tagged ‘the guy with the suitcase muffler'. I walked my suitcase mufflers in the pits, through car shows and wherever there were car nuts like me gathered. I talked to anyone who was interested."

Way back then, race tracks were starting to enforce maximum sound levels.

"‘'Common knowledge’ at that time said that race cars would lose power with the installation of mufflers, but Ray, who had already developed significant exhaust products in years past, was determined to find a way to quiet local Sprint cars (the loudest cars running at these tracks) without affecting the performance, and the Flowmaster chambered race muffler was born- not only the first-ever fully welded muffler, but one with no packing material to ‘blow out’ over time."

"As Ray carried his muffler from track to track, more racers became curious and tried the ‘suitcase’ on their cars. What they found was not only a significantly quieter car, but in most cases an increase in performance. Word spread, and within 10 years, Flowmaster mufflers had spread from northern California dirt tracks to becoming the exclusive muffler for NASCAR’s Busch North tour, as well as the official muffler of the Indy Lights series and many others."



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That Flowmaster guy is pretty interesting.
He had an original idea and followed it.

There's something to your idea of offsetting being quieter. Here's the 60 series which is claimed to be quieter than the 50 series.



It swaps the position of the plates with the resonator and has more interior offsets to exhaust flow. The dead ended Helmholtz is directly in the exhaust flow path.

Greg

 

Yeah, interesting how they swapped around the chambers in the 60 series. The 60 is much shorter, but fatter and taller than the 50. Both are about the same volume. And the 60 is only available with center inlet (maybe so the flow is lined up with the delta plates?). Flowmaster says the 60 is quieter? When I emailed them asking which is better for my engine, they recommended the 50. I got the impression the 60 is more for small cars where there may not be enough room for the 50, but I didn't ask.

I spent some quality time under my truck this morning before coming to work. Plenty of room to install an offset-inlet 50 series. I will go with that . . .

 

I had also considered the 60, but liked the more direct layout of the 50 better, and also that it had one additional angled plate and resonator.

There's scads of room under our trucks for any of their mufflers. You'll also be really happy how the 50, being much flatter than the stock muffler, will tuck way up inside your truck's frame.

Did you mean offset outlet? Mine is center in/offset out. It's not really too much of an issue as a muffler shop can make just about any configuration work.

Greg

 

Since this thread already has a lot of 2.7 performance data in it, I'll add another test, a 0-60 run.

https://www.youtube.com/watch?v=cHlV9FSipzM

Elapsed time 10.0 seconds.


I use the video markers as my timer, and didn't take off all crazy, just normally and then rolled on full throttle. Second gear gets it over 60 so there's just one shift. I also did the shift normally. Wind noise overloaded the camera's microphone. If I do another, I'll remember th roll up the windows. There's a 0-60 thread, but mostly supercharged guys posting in the 7 second range.

I think that 10 seconds is actually pretty good performance for the little 2.7.


Greg

 

Yes, the 50 just seems better.

Lots of scads of room! I am going with the offset inlet; stock is center inlet. I just wanted to make sure nothing with get in the way when the new muffler gets moved to one side. To the passenger side, it just misses (or barely touches the frame). To the driver's side, it will be about 1.5" closer to the driveshaft than the stock muffler, but there is still plenty of room. There is even enough room above to install it vertically!

Muffler arrives next Wednesday!