muffler flow

Bought a Flowmaster Deltaflow 50 part #942451. Got the # from some threads here on . It's the right size but inlet/outlet would be backwards if installed like the original one. Should I install it backwards or modify the tailpipe to make it fit ? Searched but no help. Thanks.

Flip it over

It has a label that says "inlet" on the side that would be on the outlet side (if I flip it over) and I was wondering if that would make a difference.

Don't flip it over front to back. The OE muffler is center in, offset out. That muffler is offset in center out. If there's room and it wont hit the driveshaft, flip it to the other side so the offset is toward the passenger side, it should line up. If it won't fit, make a new tail pipe.

What would happen if I install it backwards ? Would it damage something ?

Do not install backwards, It will hinder performance and ruin the tone of your exhaust. That muffler is designed to flow the direction indicated on it, If you run it backwards I will cause back presure depending on the size and if you have gone to a larger pipe. On the "in" side the first ballel is shaped like an arrow so put it in backwards and the exhaust will basically hit a wall once it enters the muffler.

:roflmao: :roflmao: :roflmao: :roflmao: :roflmao: :roflmao: :roflmao: :roflmao: hurt the flow of a flowmaster, now thats funny right there. flowmasters have been proved to be one of the worst flowing mufflers made. if you bought it for the sound then thats fine but it barelly outflows a stock muffler.
but i do agree and dont flip it around they are designed to flow a certain direction.
mike

Than I guess it would be safe to say that it's not the correct part # for a 2000 XJ... I finally got it installed correctly after a few mods. Thanks .

94xj6.5 said:

:roflmao: :roflmao: :roflmao: :roflmao: :roflmao: :roflmao: :roflmao: :roflmao: hurt the flow of a flowmaster, now thats funny right there. flowmasters have been proved to be one of the worst flowing mufflers made. if you bought it for the sound then thats fine but it barelly outflows a stock muffler.
but i do agree and dont flip it around they are designed to flow a certain direction.
mike

Click to expand...

Flowmaster is like K&N. They have been top dog for over a decade. Now everbody claims to have a slight edge over them so they call them junk. I've read test that put Lucas oil stabalizer in a blender and put K&N in a pile of dirt to prove one thing or another. I'm sure sombody found a way to test a certain built big block run at a certain RPM that makes the Flowmaster look bad too. How much flow does a 4.0 need especially at the RPM we run them at?

flowmaster is nothing like k&n. or any new info, this info has been out foreever. now i agree a 4.0 doesnt need much flow but that wasnt my point. i just get tired of people who dont know how to search for correct info and just asume that a flowmaster is a performance muffler.
sorry i dont mean to piss off the flowmaster muffler lovers
mike

Just FYI, check out these #'s when considering exhuast

Muffler Flow Testing

All tests via an independent lab
All tests @ 15” wc

2 “ Straight Pipe 283 CFM
2 ¼ “ Straight Pipe 365 CFM
2 ½ “ Straight Pipe 521 CFM

2 ¼” Typical Bent tailpipe 268 CFM
2 ½” Typical Bent Tailpipe 417 CFM

2 ¼” Inlet/Outlet_ Glass Pack Tips- No Louvers- Smooth 274 CFM
2 ¼” Inlet/Outlet- Glass Pack Tips-Louvered 133 CFM
Same as above set for reverse flow 141 CFM
2 ¼” Cherry Bomb 239 CFM
2 ½” Cherry Bomb 294 CFM

2 ½” Inlet/Outlet Dynomax Super Turbo 278 CFM
2 ½” Inlet/Outlet Ultraflow Bullet 512 CFM
2 ½” Inlet/Outlet Gibson Superflow 267 CFM
2 ½” Inlet/Outlet Flowmaster ( 2 Chamber) 249 CFM
2 ½” Inlet Outlet Flowmaster ( 3 Chamber) 229 CFM
2 ¼” Inlet/Outlet Thrush CVX 260 CFM
2 ½” Inlet/Outlet Maremount Cherry Bomb 298 CFM
2 ½” Inlet/Outlet Hooker Aero Chamber 324 CFM
2 ½” Inlet/Outlet Hooker Max Flow 521 CFM
2 ½” Inlet/Outlet Borla Turbo 373 CFM
2 1/2" Inlet/Outlet Magnaflow 284 CFM

Standard OEM 2 ¼” Inlet/Outlet 138-152 CFM
Standard OEM 2 ½” Inlet/Outlet 161-197 CFM

*****************************************************************

This test was performed by 5.0 Mustang & Super Fords Magazine, December 2002 issue (page 55) on a '90 Mustang LX coupe with 370hp and 11 second potential. 66 pulls were made for this comparison:

The results in HP order:
1.Flowtech Warlock (open) 374.2 hp/ 333.1 tq
2.Bassani Real Street 373.7 hp/ 333.8 tq
3.Hooker Maxflow 373.5 hp/ 333 tq
4.Borla XS 373.3 hp/ 332.6 tq
5.Magnaflow 372.8 / 332.5 tq
6.MAC 372.3 hp / 331.5 tq
7.Flowtech Afterburner 372.3 hp/ 330.1 tq
8.Hooker Aerochamber 372.1 hp/ 330.4 tq
9.Bassani 372 hp/ 333.5 tq
10.Spintech 371.6 hp/ 332.2 tq
11.Edelbrock Performer RPM 370.9 hp / 331.3 tq
12.Borla XR1 370 hp/ 334 tq
13.Flowtech Terminator 369.5 hp / 331.3 tq
14.Dynomax Ultra Flo 369.4 / 333.2 tq
15.Flowmaster 369.4 hp / 331.8 tq
16.Flowtech Warlock 366.3 hp / 325.3 tq
17.No muffs 365.2 hp / 330.1 tq

Sound Off in Quietest to Loudest (Decibels):
1.Borla XS, 80db at idle, 90db at 2,000 rpm, 110db at WOT.
2.Hooker Maxflow, 80db at idle, 90db at 2,000 rpm, 120db at WOT.
3.Magnaflow, 82db at idle, 91 at 2,000 rpm, 114db at WOT.
4.Flowmaster, 82db at idle, 93 at 2,000 rpm, 115db at WOT.
5.Flowtech Warlock, 83db at idle, 92 at 2,000 rpm, 112db at WOT.
6.Dynomax UltraFlo, 83db at idle, 94 at 2,000 rpm, 113db at WOT.
7.Borla XR1, 83db at idle, 96db at 2,000 rpm, 118db at WOT.
8.Bassani Street, 83db at idle, 96db at 2,000 rpm, 120db at WOT.
9.Edelbrock RPM, 84db at idle, 93db at 2,000 rpm, 118db at WOT.
10.Bassani Real Street, 84db at idle, 96db at 2,000 rpm, MAX. (120+db).
11.Flowtech Afterburner, 86db at idle, 94db at 2,000 rpm, 115db at WOT.
12.Flowtech Terminator, 86db at idle, 94db at 2,000 rpm, 119db at WOT.
13.Hooker Aerochamber, 87db at idle, 94db at 2,000 rpm, 114db at WOT.
14.SpinTech, 87db at idle, 97db at 2,000 rpm, 116db at WOT.
15.MAC, 87db at idle, 98db at 2,000 rpm, 119db at WOT.
16.No Muffler, 91db at idle, 103db at 2,000 rpm, MAX. (120+db).

The reason I went with Flowmaster isn't the sound...I would have bought a 40 series. My muffler was all bent from rocks and I wanted something that could take a few hits.

Ok, I see the results on a 370HP moter screaming to 6 grand but what about a rock bashing contest or a test with a regular moter. For me I just think a regular Turbo muffler that every muffler shop stocks flows more than enough and adds great sound. Plus they slap a new one on for 45 bucks when it gets riped open. One more question and not trying to be confrontational. How the hell does that test show that no muffler is worse than all but 1 muffler? Mufflers add power? I'm more confused now and think that a test on a jeep moter would maybe sugest a higher backpresure muffler could be better. Weird.
EDIT I just reread the test and it shows all mufflers added HP.

When I said flip it over I meant side/side, not front to back.

the inlet side has to be the inlet.

I meant turn it over so that the bottom is the top and the top is the bottom.

Thanks ninie mile...it's already on. Just making sure I had everything right.

guillermo said:

Than I guess it would be safe to say that it's not the correct part # for a 2000 XJ... I finally got it installed correctly after a few mods. Thanks .

Click to expand...

It was almost the right #. You should have got part #942452.

Stumpalump said:

How the hell does that test show that no muffler is worse than all but 1 muffler? Mufflers add power? I'm more confused now and think that a test on a jeep moter would maybe sugest a higher backpresure muffler could be better. Weird.
EDIT I just reread the test and it shows all mufflers added HP.

Click to expand...

IIRC, most engines run better with some back pressure.

"Ok, I see the results on a 370HP moter screaming to 6 grand but what about a rock bashing contest or a test with a regular moter. For me I just think a regular Turbo muffler that every muffler shop stocks flows more than enough and adds great sound. Plus they slap a new one on for 45 bucks when it gets riped open. One more question and not trying to be confrontational. How the hell does that test show that no muffler is worse than all but 1 muffler? Mufflers add power? I'm more confused now and think that a test on a jeep moter would maybe sugest a higher backpresure muffler could be better. Weird.
EDIT I just reread the test and it shows all mufflers added HP."

Click to expand...

because back pressure helps with scavagening(pulling exhaust gas out of the cylinder) most everything short of a race car at WOT needs some form of back pressure.

WheelsUp said:

IIRC, most engines run better with some back pressure.

Click to expand...

not all.

not all, that would almost be like most eh?