Dyno runs.. what gear on a 6MT?

Guess · 09-09-2009, 08:58 AM

I have done a couple of pulls in 4th gear on the dyno, and I am wondering as I just read a couple of threads with people mentioning doing 3rd gear runs. What gear are you guys using for your dyno pulls?

Thanks!

enrita · 09-09-2009, 09:00 AM

always 4th

oddjob2021 · 09-09-2009, 09:06 AM

our fourth gear usually yield higher numbers. not sure of the technical reason of load or something, but from a laymens standpoint, you have more time in the dyno run to see peaks and valleys of the run in a higher gear.

kyleb350 · 09-09-2009, 09:08 AM

I heard it was because the gear ratio is closest to 1:1

Guess · 09-09-2009, 09:09 AM

Quote:

Originally Posted by kyleb350

I heard it was because the gear ratio is closest to 1:1

This is exactly why. Its all about a 1:1 ratio. I remember my 325i I actually did the research and it was truly 4th, I am just trying to verify that it is indeed the same on the 335i's

jpsimon · 09-09-2009, 09:14 AM

We did a test at a dyno day: back-to-back 3rd and then 4th gear pulls on the same car. The power output was exactly the same.

I always have to use 3rd on my car because the AWD goes bonkers when trying 4th gear.

edo · 09-09-2009, 10:05 AM

Quote:

Originally Posted by Guess

What gear are you guys using for your dyno pulls?

The most accurate numbers are when using 5th gear (1:1 gear ratio).

Zeph · 09-09-2009, 10:13 AM

4th takes a LONG time to dyno going from 2k to 7k lol... the dyno guy was like "that is a tall gear" and I told him that he just went about 142 mph and starting all the way down around 2k rpm's takes a while. It is, apparently, the 1:1 gear though so that is what I use. I would almost rather use 3rd since it would decrease my stock FMIC heat-soak

flem · 09-09-2009, 10:26 AM

Quote:

Originally Posted by Zeph

4th takes a LONG time to dyno going from 2k to 7k lol... the dyno guy was like "that is a tall gear" and I told him that he just went about 142 mph and starting all the way down around 2k rpm's takes a while. It is, apparently, the 1:1 gear though so that is what I use. I would almost rather use 3rd since it would decrease my stock FMIC heat-soak

5th gear is the 1:1 gear... Straight from BMW's website:

Quote:

Transmission
Gear ratios – I/II 4.06/2.40 [4.17/2.34] :1
Gear ratios – III/IV 1.58/1.19 [1.52/1.14] :1
Gear ratios – V/VI/R 1.00/0.87/3.68 [0.87/0.69/3.40] :1
Final drive ratio 3.08 [3.46] :1

The figures that are in [ ] apply to the automatic

iPodAddict · 09-09-2009, 11:27 AM

5th gear - unless the shop knows and adjusts the ratio for the desired gear to be used instead.

09-09-2009, 08:58 AM	#1
Guess BlackBerry King 41 Rep 184 Posts Drives: 2009 BMW 335i Join Date: Sep 2005 Location: Kitchener, ON, Canada iTrader: (0) Garage List 2009 335I [0.00] 2006 325I GONE (OLD ... [10.00]	Dyno runs.. what gear on a 6MT? I have done a couple of pulls in 4th gear on the dyno, and I am wondering as I just read a couple of threads with people mentioning doing 3rd gear runs. What gear are you guys using for your dyno pulls? Thanks! __________________ 2009 BMW 335i /6 SPD Fully Loaded Saphire Black on Black Dakota Leather
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09-09-2009, 09:00 AM	#2
enrita Major General 161 Rep 7,377 Posts Drives: 335i - Big turbos Join Date: Sep 2008 Location: Italian in Sweden iTrader: (0)	always 4th __________________ 07 335i AT - MOTIV 750 - MHD E85 BMS flash - BMS PI - JB4G5 - Okada Coils - NGK 5992 Plugs - Helix IC - Snow Stg. 3 - Stett CP - Custom midpipes with 100 HJS Cats - Bastuck Quad - PSS10 - QUAIFE LSD - BMS OCC - Forge DVs - AR OC - ALCON BBK - M3 Chassi - Dinan CP - Velocity M rear Toe arms - Advan RZ-DF - LUX H8 - Level 10 AT upgrade
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09-09-2009, 09:06 AM	#3
oddjob2021 ASR Turbos+LSD+Meth= :D 73 Rep 1,517 Posts Drives: E92 335i Join Date: May 2007 Location: Miami, FL iTrader: (0) Garage List 2007 E92 335i [0.00]	our fourth gear usually yield higher numbers. not sure of the technical reason of load or something, but from a laymens standpoint, you have more time in the dyno run to see peaks and valleys of the run in a higher gear. __________________ 2007 335i Coupe Mods: Check the Garage
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09-09-2009, 09:08 AM	#4
kyleb350 Brigadier General 424 Rep 4,709 Posts Drives: '21 X3MC Join Date: Jun 2008 Location: Milwaukee iTrader: (6)	I heard it was because the gear ratio is closest to 1:1
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09-09-2009, 09:14 AM	#6
jpsimon Team Zissou 3065 Rep 10,197 Posts Drives: 2022 AWD M3 Comp - SMB Join Date: Dec 2006 Location: CT iTrader: (7)	We did a test at a dyno day: back-to-back 3rd and then 4th gear pulls on the same car. The power output was exactly the same. I always have to use 3rd on my car because the AWD goes bonkers when trying 4th gear.
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09-09-2009, 10:13 AM	#8
Zeph Major 27 Rep 1,410 Posts Drives: 2008 E92 335i 6MT SGM CR/BD Join Date: Jul 2008 Location: Southeast USA iTrader: (0)	4th takes a LONG time to dyno going from 2k to 7k lol... the dyno guy was like "that is a tall gear" and I told him that he just went about 142 mph and starting all the way down around 2k rpm's takes a while. It is, apparently, the 1:1 gear though so that is what I use. I would almost rather use 3rd since it would decrease my stock FMIC heat-soak
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09-09-2009, 11:27 AM	#10
iPodAddict Captain 28 Rep 964 Posts Drives: 335i Join Date: Sep 2007 Location: Xinpei iTrader: (0)	5th gear - unless the shop knows and adjusts the ratio for the desired gear to be used instead. __________________
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