longarm
Car sold back to original owners
Interesting test using Magnaflow mufflers.
2 1/2" vs 3" Exhaust Comparison Video
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JoesEdge
Well-Known Member
Those 2.5 inch Magnaflows seem very quiet. I think I want a pair. My chambered Jeg's can get tiring on the highway.
abodyjoe
Well-Known Member
below 3200 the smaller pipe is better... other than that on a 620 horse motor the 3" is as close to open headers as can be while the 2.5" killed 20hp. no real surprise there..
why don't they try it on a 350-400 horse motor? that would be more the regular guy type of power..
why don't they try it on a 350-400 horse motor? that would be more the regular guy type of power..
JoesEdge
Well-Known Member
I totally agree. They should do it on something more typical of a street car.
Although, if you're pushing over 600 HP and it's a street driven car. I wouldn't care to losing 20 HP if it makes the drivability more pleasant (i.e. quieter), although others may differ. They may not mind the extra noise.
longarm
Car sold back to original owners
I think you could extrapolate from the demo that 2 1/2" would probably
be enuff for a naturally aspirated 450hp and less engines.
It still leaves room to discuss the merits your favorite crossover.
be enuff for a naturally aspirated 450hp and less engines.
It still leaves room to discuss the merits your favorite crossover.
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Why wasn't the jetting changed when the 2.5" system was showing rich. The engine appeared to like the open header A/F ratio. Kind of invalidates any comparison.
longarm
Car sold back to original owners
I don't believe most car guys do more than change out parts and
would never fine tune a carb or miss that much HP/TQ.
I guess you would have to take the info provided and your real world experience
and make your best guess as to how it pertains to your application.
would never fine tune a carb or miss that much HP/TQ.
I guess you would have to take the info provided and your real world experience
and make your best guess as to how it pertains to your application.
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racerkilla
Well-Known Member
I run magnaflow 2.5 on my duster.. very mellow idle and decent part throttle cruising. A wot pull they make a bit of noise. Not a fan of chambered mufflers anymore.
This is a 340 with headers, full 2.5, magnaflow and a body stainless tips. 5000 Rpm
Lustle
Well-Known Member
An interesting episode for sure. Especially how little power loss there was with how long of pipe they had.
If you're ever wondering what exhaust to run on your setup. Consult this chart.
For the full maths, go here: http://www.exhaustvideos.com/faq/how-to-calculate-muffler-size-pipe-diameter/
It explains it all. But in short. A certain amount of horsepower flows a certain CFM. And a certain CFM requires a certain pipe size. Not really as complicated as it seems. I am going 3 inch on my setup. It's a lot. My 340 is really only going to put out 420ish horsepower. But I will be running nitrous. And with that I can definitely hit close to 600. Not to mention I will be doing head and cam work this winter and should end up in the 475 area N/A. 2-3/4 pipe being difficult to find I went 3 inch. Am I worried about torque loss down low? Not really. I'm going with an H pipe setup which should help balance things out. Going from manifolds and 2-1/4 to full length headers and 3 inch exhaust should make a serious improvement in my power. I'm curious to see what it does.
If you're ever wondering what exhaust to run on your setup. Consult this chart.
For the full maths, go here: http://www.exhaustvideos.com/faq/how-to-calculate-muffler-size-pipe-diameter/
It explains it all. But in short. A certain amount of horsepower flows a certain CFM. And a certain CFM requires a certain pipe size. Not really as complicated as it seems. I am going 3 inch on my setup. It's a lot. My 340 is really only going to put out 420ish horsepower. But I will be running nitrous. And with that I can definitely hit close to 600. Not to mention I will be doing head and cam work this winter and should end up in the 475 area N/A. 2-3/4 pipe being difficult to find I went 3 inch. Am I worried about torque loss down low? Not really. I'm going with an H pipe setup which should help balance things out. Going from manifolds and 2-1/4 to full length headers and 3 inch exhaust should make a serious improvement in my power. I'm curious to see what it does.
ir3333
Well-Known Member
i think we just watched an Edelbrock,holley,comp cams,wiseco,hooker,amzoil,and Magnaflo
commercial.
commercial.
Two things come to mind with your statement.
1; You don't always see or hear them say they did "***" to the engine since they are time limited. Not to mention making every mention of every little thing is boring and tedious.
2; Even if they did not, the jet change is small potatoes in the grand scheme of things. There not getting back the lost power.
I do not consider it an invalidated test.
Half a point fat on an engine that hp could easily be 15hp... BTDT... Takes 5 minutes to change both ends with 2 people if you are capable.
Testing is about constants... this "test" didn't have that.
Testing is about constants... this "test" didn't have that.
crackedback, so what your telling me is, you can tune the 15.7tq & 13ho back in?
Possibly. You'll never know because they didn't remove that variable.
Testing requires constants, and they failed miserably with the A/F ratio change.
Testing requires constants, and they failed miserably with the A/F ratio change.
Well then, I look forward to you dyno skills being displayed.
Double post
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This isn't about me... IT'S ABOUT THE DATA THEY PRODUCED WHICH HAS A HUGE FLAW IN IT.
Get it! Carry on.
Get it! Carry on.
Lustle
Well-Known Member
All this "Rich vs not rich" aside.
I'm curious how much of those losses they would have gained back with a H or X pipe.
I'm curious how much of those losses they would have gained back with a H or X pipe.
Hey Ho Whoa whoa whoa hey! Stop screamin at me.
I did ask if YOU can tune back the power and YOU said possibly. So I say I look forward to it. Relax!
I'm not trying to be a punished here or argue against what your saying.
In the video, how rich was it off being in tune?
Good thought there Lustle.
JoesEdge
Well-Known Member
That should be their next video! Would be interesting.
yellow rose
Overnight Sensation
I don't know where this chart comes from, but if take 2 CFM per HP.
I can tell you most of these rule of thumb charts are wrong, and they err way on the small side.
Look at carbs. For DECADES people thought a dominator was too big for everything. Now they are on everything. The charts were always wrong. I don't put much into the above chart either.
ir3333
Well-Known Member
are you guys convinced these tests are legit?
The last one showed a 335 hp 383 with a cam,headers and intake change increasing the output by 145 hp?
..and the stock 340 test with XE268 cam,headers and intake change putting out 391hp?
The last one showed a 335 hp 383 with a cam,headers and intake change increasing the output by 145 hp?
..and the stock 340 test with XE268 cam,headers and intake change putting out 391hp?
Lustle
Well-Known Member
Did you read the full article and see the math he came up with? He figures it out down to the last CFM. I trust that chart as a good guide. But as a general rule when I am stuck between one smaller and one larger size, I go the larger size.
One day, I'm going to retire and just do dyno testing. Just because.
Lustle
Well-Known Member
Yup. If I ever won the lottery I would basically just build engines and test various parts. See what a "set of heads and cam" really net you. From my point of view though? Yes, a set of cam, heads and intake can net 145 horse. If the heads are setup right and bump your compression up. If the cam is right and has good lift/duration. And if the intake is a good design. Let's not forget how much power you can gain just by porting heads. Horsepower is out there folks. Just gotta find it.
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