BMW M3 Forum (E90 E92)

BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read


Go Back   M3Post - BMW M3 Forum > E90/E92 M3 Technical Topics > Engine, Transmission, Exhaust, Drivetrain, ECU Software Modifications
 
BPM Sport
Post Reply
 
Thread Tools Search this Thread
      01-20-2012, 05:17 PM   #1
ucla bruin
Second Lieutenant
9
Rep
235
Posts

 
Drives: daily moped
Join Date: Dec 2011
Location: CA

iTrader: (0)

Unhappy RPI GT and GTM confusion

Can anyone clear this up for me? I've tried searching and have heard conflicting things from different people.

Is the RPI GT axle back the same as the axle back from the GTM exhaust? In other words, is RPI GT exhaust only referring to the rear section?

GT + x pipe = GTM?


Thanks!
Appreciate 0
      01-20-2012, 05:46 PM   #2
avex8
Captain
avex8's Avatar
13
Rep
814
Posts

 
Drives: 11 E92 M3, 13 X3 35i, 14 650i
Join Date: May 2011
Location: San Diego

iTrader: (3)

GT and GTM refer to the axle back. GT is the old version which has rasp and ring noise. GTM is the newest version which cleans out the ring noise.
Appreciate 0
      01-20-2012, 05:48 PM   #3
ucla bruin
Second Lieutenant
9
Rep
235
Posts

 
Drives: daily moped
Join Date: Dec 2011
Location: CA

iTrader: (0)

So the 2 axle backs, although look the same, are internally different and sound different?
Appreciate 0
      01-20-2012, 06:10 PM   #4
Cal@Sonic MS
Cal@Sonic MS's Avatar
United_States
194
Rep
4,653
Posts

 
Drives: bmw
Join Date: Jan 2011
Location: earth

iTrader: (2)

Quote:
Originally Posted by ucla bruin View Post
So the 2 axle backs, although look the same, are internally different and sound different?
That's correct. The GT unit is discontinued and currently on clearance sale I believe. The RPI GTM superseded the GT unit.
Appreciate 0
      01-20-2012, 06:12 PM   #5
dvpouldar26
Major
dvpouldar26's Avatar
25
Rep
1,496
Posts

 
Drives: 2008 e92 328i, Porsche 987.1
Join Date: May 2008
Location: Beverly Hills, CA

iTrader: (4)

Quote:
Originally Posted by ucla bruin View Post
So the 2 axle backs, although look the same, are internally different and sound different?
They are 2 different axle backs, both offered by RPI. The GT was introduced first and most hated that annoying tin can ringing sound, so they came out with s second version, the GTM. Visually they look different because the GT has its inlet pipe out of the side of the muffler while the GTM's inlet pipe goes in through the back of the muffler.

PS: Go Bruins!
__________________
E92 328i
Jet Black / Gloss Black Grilles / 8000k D1S low beam / 6000k HID fogs / GP Thunder 8500k angels & cornering bulbs / black reflectors / gloss black vinyled window trim / tints / smoked rear turn signals / black roundels / AC Schnitzer roof spoiler / VRS style decklid spoiler / Matte black Stripes / Rear fogs / matte mirrors / 19" LM reps / APR lip
Appreciate 0
      01-20-2012, 06:27 PM   #6
geneatals
Ninja
geneatals's Avatar
Philippines
44
Rep
3,207
Posts

 
Drives: 2011.5 E90 M3
Join Date: Dec 2007
Location: So Cal (SFV)

iTrader: (2)

***I thought the "ting" sound came from the rpi mid pipe+gt axle back...

gt+stock mid pipe produced no ting...perhaps I am mistaken...

either way..rpi section 1 and section 2 pipes are still the same for both gt and gtm...
__________________
2011.5 E90 M3 AW l Black Novillo Leather | Carbon Fiber Leather Trim | ZCP | ZP2 | M-DCT | Navigation | Moonroof | 6FL l Pics/Mods
Retired: 2008 535i l AW l Black Dakota Leather l Bamboo Anthracite l ZPP l ZSP l 6FL
Appreciate 0
      01-20-2012, 07:22 PM   #7
Raptor251
ESS Dreaming
Raptor251's Avatar
United_States
10
Rep
870
Posts

 
Drives: 2011.5 e92 m3/Ford Raptor 6.2
Join Date: Jan 2011
Location: San Diego

iTrader: (1)

Quote:
Originally Posted by geneatals View Post
***I thought the "ting" sound came from the rpi mid pipe+gt axle back...

gt+stock mid pipe produced no ting...perhaps I am mistaken...

either way..rpi section 1 and section 2 pipes are still the same for both gt and gtm...

The "ting" sound comes from the dramatic increase in exhaust velocity when the cats are removed on the GT system. The side inlet muffler design on the GT doesn't allow the exhaust gases to flow properly. The GTM mufflers have the rear inlet and are very loud!
Appreciate 0
      01-20-2012, 07:36 PM   #8
ucla bruin
Second Lieutenant
9
Rep
235
Posts

 
Drives: daily moped
Join Date: Dec 2011
Location: CA

iTrader: (0)

Thanks for all the info.

Hoping to hear GTC in person this weekend.

GT for sale if anyone's interested for a low price!
Appreciate 0
      01-20-2012, 08:42 PM   #9
kchu221
JDM whore
kchu221's Avatar
South Korea
45
Rep
3,021
Posts

 
Drives: 2009 Porsche 911 Turbo
Join Date: Jan 2012
Location: los angeles

iTrader: (9)

danny you getting a bmw???
Appreciate 0
      01-20-2012, 11:21 PM   #10
ucla bruin
Second Lieutenant
9
Rep
235
Posts

 
Drives: daily moped
Join Date: Dec 2011
Location: CA

iTrader: (0)

Haha nice seeing you on here. I picked one up recently. Sent you a PM!
Appreciate 0
      01-21-2012, 01:26 AM   #11
geneatals
Ninja
geneatals's Avatar
Philippines
44
Rep
3,207
Posts

 
Drives: 2011.5 E90 M3
Join Date: Dec 2007
Location: So Cal (SFV)

iTrader: (2)

gtc has been installed on a so cal e92 (axle back only)...today IIRC...said to be 50% quieter than the gtm....have not heard in person yet tho...
__________________
2011.5 E90 M3 AW l Black Novillo Leather | Carbon Fiber Leather Trim | ZCP | ZP2 | M-DCT | Navigation | Moonroof | 6FL l Pics/Mods
Retired: 2008 535i l AW l Black Dakota Leather l Bamboo Anthracite l ZPP l ZSP l 6FL
Appreciate 0
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 01:49 AM.




m3post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST