Muffler Delete Z4M Video Clips

Z4MCJJ · 07-26-2009, 03:27 AM

Quote:

Originally Posted by The__J__Factor

Rpi exhaust is just a muffler delete, theres no reason why another muffler delete would lose hp while another gains hp.
Its not like there are many routing options for the last 1 foot of piping and pretty hard to make something really bad.

I agree with what you're saying, but it seems the RPI exhausts are not quite straight pipes...no?

The__J__Factor · 07-26-2009, 04:17 PM

Their 1st proto type was straight pipes, their final design has a small muffler put in. I think the dyno showing their gains was the original without a muffler, not 100% sure.

laidback · 07-26-2009, 05:28 PM

The RPI GT exhaust has two small mufflers and the gains are from that same muffler...loss hp was from straight pipes...

Quote:

Originally Posted by The__J__Factor

Their 1st proto type was straight pipes, their final design has a small muffler put in. I think the dyno showing their gains was the original without a muffler, not 100% sure.

Quote:

Originally Posted by Z4MCJJ

I agree with what you're saying, but it seems the RPI exhausts are not quite straight pipes...no?

Evoking · 07-29-2009, 08:06 PM

I have not dyno'd it. But isn't it safe to say that if you had a tune on stock exhaust and you go to straight pipes WITHOUT retune that this could have been the reason for the decreased power?

The computer was specifically tuned for when you had the stock exhaust... I wonder if thes same loss would have happened on a bone stock "non-tuned" car. I also want to get the ESS and have it dyno'd. Although I don't have a baseline I'll still know what I'm doing with the mufflers in place and can compare against others.

Btw, here are some pics of the install. Excuse the Blackberry camera.

http://www.zpost.com/forums/showthread.php?t=286853

07-26-2009, 04:17 PM	#24
The__J__Factor Major 88 Rep 1,090 Posts Drives: ///M Coupe Join Date: Sep 2008 Location: Gold Coast, Australia iTrader: (0)	Their 1st proto type was straight pipes, their final design has a small muffler put in. I think the dyno showing their gains was the original without a muffler, not 100% sure. __________________ 135i N54 manual MR-S with a 2zz swap and mods Sold EVO X MR - Phantom Black - Ti Exhaust - Ti UICP - AQM Intake - Sold Z4 M Coupe - H&R - RE Diablo - RPi - Tekarbon - Sold
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07-29-2009, 08:06 PM	#26
Evoking First Lieutenant 95 Rep 304 Posts Drives: Z4M Coupe Join Date: Apr 2007 Location: Dallas, TX iTrader: (0)	I have not dyno'd it. But isn't it safe to say that if you had a tune on stock exhaust and you go to straight pipes WITHOUT retune that this could have been the reason for the decreased power? The computer was specifically tuned for when you had the stock exhaust... I wonder if thes same loss would have happened on a bone stock "non-tuned" car. I also want to get the ESS and have it dyno'd. Although I don't have a baseline I'll still know what I'm doing with the mufflers in place and can compare against others. Btw, here are some pics of the install. Excuse the Blackberry camera. http://www.zpost.com/forums/showthread.php?t=286853
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