Magnaflow versus Flowmaster ~ Showdown on the Dyno

While one mpg isn't a lot, your gas mileage chart is consistently higher with the Flowmaster muffler, and that's significant because it's outside the margin of error of one fill up.


Greg

 

I sure do like it.

I was totally used to the big Magnaflow before, so the Flowmaster 50 seems plenty loud. But what really surprized me is how smooth the sound is. I listened to so many Flowmaster sound videos, I had expected a rougher more harsh sound. When I get on the gas, it makes this strange hollow metallic whooshing sound. It was even kicking out the sound limiter on my camera in the high rpms.


Greg

 

I had a Gibson exhaust on my fj and loved it and it got slightly softer over time

 

Thanks so much for bringing up that great idea to calculate the dollar cost per horsepower gained!

Even though I went for torque and not horsepower, I'll do the same just for comparison. Here is the cost of the performance mods:

MagnaFlow 22 inch muffler $65
Custom built mandrel bent exhaust $300
LCE long tube header $475
tooter intake manifold spacer $0
Injen warm air intake $220
Removed air conditioning and pulleys $0
Removed power steering and pulleys $0
Short simple drive belt for water pump and alternator $20


Total cost: $1,080

Stock baseline 2.7 dyno test:

119hp @ 5,200 rpm
133 ftlbs @ 3,800 rpm

My latest dyno test:

139hp @ 4,600 rpm
162 ftlbs @ 2,900 rpm

The speed limiter cut off the 4th gear runs, so I might have made a few more horsepower, but I'll use these numbers because they are what I can actually document. When I do the next Flowmaster dyno test, I'll do one third gear run all the way up just to see what the full horsepower gain is, if any.

So the 20 horsepower gain cost me $1,080. I paid $54 per horsepower.

The mods I did were all to get more torque at lower rpms so I got a lot more of that.

29 ftlbs for the same $1,080... so the added foot pounds of torque only cost $37 each.

So while the gains are modest... the cost per unit of gain is also pretty modest.


Greg

 

Couple questions again haha did you get your truck retuned once you had all these mods done?

And also with the increase in power, did you gain MPG or did you lose it?

 

No problem, enjoying the thread. Your $/hp and especially torque/hp is really pretty good.

 

I don't have a catalytic converter and have a aftermarket muffler and tailpipe and my truck runs just fine haven't felt any lose in low end torque and have see a little kick In higher rpm range.

 

No. No tuning. Just whatever the stock ECU automatically adjusts itself to.

So far, I've gained 1 mpg. Not any less for sure, but not much more than that either. Part of the reason is that my truck is a service vehicle so it's always fully loaded, it isn't driven on the freeway, and most all of my driving is in first, second, and third gear on small rural roads.


Greg

 

Ah, you have a 96...
I had one for 17 years and loved it.Your engine has really long intake runners which is excellent for getting good gas mileage.



Your truck is also smaller and lighter.


Greg

 

So do you think now that you have all those mods stacked up if you got it tuned it would be better gains?

That's what I'm afraid of putting more power in my truck... My dad's hemi I had to borrow and I got 9.8mpg here. He gets 18mpg in pheonix. So I'm worried that if I start gaining power, I'll definitely lose mpg. Up and down hills, stop and go at max 35mph is not good with more power

 

subbed for flowmaster dyno... i have a flowmaster 44 on my truck now. got a magnaflow in my truck bed waiting to be installed. been hunting for a sound but if i find out the magnaflow will give me better hp or tq then i might just switch for that reason. Hard to decide. I like the flow master but i do hear a lot of rasp with it around 3k rpm.

 

Did you keep all 4 cats? Did you dump it or out the back?

 

only got 2 left with my URD long tubes removing the first two at the manifold. still have stock tubing all the way.

 

We'll know soon...
I talked with Harry the dyno shop guy today, and we're scheduled to do the Flowmaster runs on Friday the 11th. I'll post up the results as soon as I can.

Yeah, the two chamber mufflers have less noise cancelling features inside of them. From driving around with the 50 series delta flow, it's still way loud, but there's no rasp at all even with just a small 4 banger wheezing into it. I would think that a 6 cylinder would be even smoother. I'm really impressed with the "tuned formula 1" like sound. I need to take some regular driving videos to give you a better idea of the sound. What throws it off is my camera has a sound equalizer built into it to it that automatically reduces the recording volume as the exhaust gets louder so you don't actually hear the contrast from quiet to loud. But at least you'll be able to hear the sound quality if not the true volume.

Greg

 

It's highly likely. But right now I can't introduce another variable into the testing. The only change has to be just the muffler for each test. I'm not as much interested in open loop high rpm wide open throttle performance as I am in low rpm torque under normal everyday partial throttle driving conditions.

With power always comes the responsibility to control it.


Greg

 

Oooh...
Do you have any pics of your URD long tubes installed? I think their design is an absolutely beautiful work of art.

What are your driving impressions with the headers as compared to before?

I'd love to see a dyno chart with them. Do you know if URD has done any?


Greg

 

Ohh okay. Then if you O2 sensors (if not buy them), get it repiped after the headers to a Y-pipe then into the muffle, then out the back or dumped. Those cats are horrible and repiping with a slightly bigger pipe usually helps (from my experience)

 

After maybe do the retune and see the gains? That'd be interesting to see the $/hp & $/tq for a retune, and if it's really wort it

Tell me about it, my subaru had 308whp, I had to tune my turbo to never be on so I could control myself from wasting gas having fun

 

You may want to just ditch the flowmaster... If you have the regulat aluminumized one and not the stainless, the baffles are probably rusted out already. Mine went in two years. After removing it, I shook it and all the rusted pieces fell out. The magnaflow that you have will be pretty loud, and with the two cats removed, there will be some raspiness when stomping on it. You may want to install a resonator along with the magnaflow. Mine is almost like yours, but I have stock headers with URD y pipe, but I put the biggest magnaflow that I could, the 24" case.

 

I'm really glad Flowmaster is producing all stainless steel mufflers now. They're just a few dollars more than the regular ones and well worth it. I intend to use mine for many years. What I like most is that the sound won't change from the first day it's installed because there's no packing to get blown out.

Greg