Anyone feel a difference with an aftermarket exhaust?

[MrHarris]

I got a Remus race, and sometimes I feel as if my car may actually be slower. A friend of mine said my car doesn't accelerate as violently as before. Anyone else feel a difference with their aftermarket exhaust? Good or bad.

[serven7]

Thats because you dont have an exhaust, you have a muffler(big difference). You must get a proper exhaust before you can realistically expect gains. At least the Remus sound good!

[MrHarris]

I know, but I feel sometimes with the Remus muffler that my car is slower :T

[satinghostrider]

I am running the ACS Race muffler which is essentially made by Remus, and I feel a good gain in the mid-high. The rpm does not feel as restricted as before. Definitely a gain IMHO. Only loss is that its a cop magnet.

[serven7]

Originally Posted by MrHarris

I know, but I feel sometimes with the Remus muffler that my car is slower :T

If thats the case take it off and sell it, plenty of people that want one of those.

I am running the ACS Race muffler which is essentially made by Remus, and I feel a good gain in the mid-high. The rpm does not feel as restricted as before. Definitely a gain IMHO. Only loss is that its a cop magnet.

I feel that these mufflers are like a placebo, they make you think your car is faster. I dont think there are too many people out there that call tell a 3-7whp gain in a 400+hp car.

[satinghostrider]

Originally Posted by serven7

If thats the case take it off and sell it, plenty of people that want one of those.



I feel that these mufflers are like a placebo, they make you think your car is faster. I dont think there are too many people out there that call tell a 3-7whp gain in a 400+hp car.

Thats absolutely true. But its quite noticeable that the revs are much more free mid-high end as you stretch. This may or may not equal power but its a good butt dyno for at least 3-5hp at the very most.

[spyderco10]

I just put the Borla on mine. It feels like it may have lost some low end power, but feels a little faster in the mid to high end. Or then again it could just be the power of suggestion. But the Borla system is 20lbs lighter than stock, so that should help too.

[MrHarris]

Originally Posted by spyderco10

I just put the Borla on mine. It feels like it may have lost some low end power, but feels a little faster in the mid to high end. Or then again it could just be the power of suggestion. But the Borla system is 20lbs lighter than stock, so that should help too.

Same here. From 2k-4k it feels not as strong but above 5k it feels stronger. Weird.

[BimmerRob08]

this is an interesting topic, I'm still trying to collect data before I make a muffler purchase and this don't sound to promising. I'd expect that at low rpm's as well as high rpm's that reduced exhaust pressure would aid in rpm spin up and not hinder it at low rpm's. anyone have a valid explaination on this? What about any dyno tests? I've seen some (can't remember which posts) that showed slightly higher torque and hp through out the range from low to high rpms. But some of you guys are already experiancing low rpm loss of power.

[J08M3]

My explanation is all these gains and losses are in the mind of the driver. The power of the mind and suggestion and what it wants to believe are amazingly strong. No way changing just the muffler is making any difference anyone on here can feel aside from the sound of the car. The louder sound and the money spent is what most people are equating to more horsepower. I suggest buying muffler strictly on quality of build and sound you like best. Probably the biggest benefit is saving a few pounds of weight depending on what muffler you choose over stock.

[BimmerRob08]

ya, I agree. I think back when I had a '04 Saab 93 Aero turbo. Changed the mufflers to borla, it sounded better, and maybe a % or 2 better on the exelleration because their less restrictive and being a turbo I guess, they definitly needed a less restrictive muffler. Either than that, it was more of a sound issue and not hp gain or loss. At least my butt dyno didn't really feel a huge difference, definitaly not a loss in power. Although I'll tell you that the ver next day after the install, the ECU of the 93 went into a "reduced power" mode for a while with no engine check-lights. I called the dealer, over the phone they could not suggest any issues. Then after shut down, and restart later, it worked fine and has been ever since as a girl friend of mine now ownes it and no problems since the install. I wonder if the ECU was re-learning the exhaust pressure for a few miles and then was reset with the new perameters??

[PunjabiM3]

I would be surprised if a muffler added any power. Maybe 1 or 2 hp if you must be optimistic. Hopefully it doesn't cause any loss of power! I'm not sure if my Eisenmann Race made any difference plus or minus, but sometimes I feel that my car does not accelerate as fast ever since I installed the AFE filter.

[serven7]

before this conversation gets off topic lets remember why you guys bought the Remus or Borla, because its a cheep way to make your car sound good and if thats all you were after then right on you got what you came for. A full header back system is a considerable bit more money but just like anything you get what you pay for. Now, with that being said the guys that went out and bought the eisnmann $3500 glorified muffler thats a whole different story.

[J08M3]

Your car can accelerate slower or faster just depending on the weather from day to day.

[William Blake]

Originally Posted by PunjabiM3

I would be surprised if a muffler added any power. Maybe 1 or 2 hp if you must be optimistic. Hopefully it doesn't cause any loss of power! I'm not sure if my Eisenmann Race made any difference plus or minus, but sometimes I feel that my car does not accelerate as fast ever since I installed the AFE filter.

Leave that intake system OEM. AFE does nothing (or worsens it)

[Edman951]

Could it be because our motor doesn't have a MAF sensor, it use's a MAP sensor.
That with small increased in flow, the ECU doesn't adjust the fuel perfectly.
Making the car run different, and not at peak performance.

Map sensor aren't good with increased flow corrections compared to MAF.
Increased flow would not be detected by the MAP sensor.
Since it mesures pressure/vaccum changes, and increased flow doesn't affect pressure or vaccum.

On cars with MAP sensors, normally any changes in intake or exhaust requires a retune to optain peak performance.

[MrHarris]

I think I'll be taking my car to RPi to do a dyno. I'll post my results. They tested my car stock and with scoops.

[DLSJ5]

Best way to see if there's any real gains are Vbox runs, 1/4 mile runs, or do a comparo with a bonestock car before and after the exhaust. If Turner Motorsport is correct, the real gains come from software and front cat delete, gears as well, but muffler's I would think not much.

[BimmerRob08]

Originally Posted by Edman951

Could it be because our motor doesn't have a MAF sensor, it use's a MAP sensor.
That with small increased in flow, the ECU doesn't adjust the fuel perfectly.
Making the car run different, and not at peak performance.

Map sensor aren't good with increased flow corrections compared to MAF.
Increased flow would not be detected by the MAP sensor.
Since it mesures pressure/vaccum changes, and increased flow doesn't affect pressure or vaccum.

On cars with MAP sensors, normally any changes in intake or exhaust requires a retune to optain peak performance.

can you put that in simpler terms for us? Are you saying that our M3 does not have a MAP sensor or a MAF? What is a MAP or MEF by the way??

[J08M3]

It's different ways of measuring the amount of air going into the engine. MAP = Manifold Air Pressure (I think not sure??), MAF = Mass Air Flow.

[MMMorish]

Originally Posted by William Blake

Leave that intake system OEM. AFE does nothing (or worsens it)

Interesting. Can anyone verify this or comment further??

[spyderco10]

Originally Posted by MMMorish

Interesting. Can anyone verify this or comment further??

At least you can clean it when it gets dirty, and don't have to buy new ones.