Driving a manual E90

achtung · 04-18-2006, 09:16 PM

Dear All

My last car has a sequential manual gearbox that did all the blipping, heel/toe for me.... now on a manual E90 320i and have some questions. Not at the heel/toe or double declutch stage yet.....

... just trying to match revs and speed.

Some questions:

Will the following cause damage to my gearbox or prop shaft

Revs lower than car speed
(1) There are times when I downshift from 5th to 3rd on the highway and did not blip the throttle enough, so there is a jerk when I release the clutch.
(2) When doing a quick get-away from the lights, while shifting from 1st to 2nd, release the clutch too quickly before there is enough throttle, there is also a jerk.

Revs higher than car speed
Of course there are times when I blip too much and engine speed is higher than the car's speed. There will also be a jerk

I was thinking.... if the the driven wheels are going at a certain speed and it is not matched to the engine (or should I say gearbox) speed. The opposing forces will probably meet somewhere. My guess is it meets at either the prop shaft, the clutch, the gearbox or the engine. That is some major material stress right? What kind of wear will there be?

Thanks
Achtung

stressdoc · 04-19-2006, 09:14 AM

It's a BMW. Have no fear.

poldim · 04-19-2006, 09:36 AM

Quote:

Originally Posted by stressdoc

It's a BMW. Have no fear.

Wrong. Have fear. Doing this constantly is putting excessive stress on your clutch and syncros. Just because its a BMW, doesnt make it invincible, ask hotsand5.

If you are doing this harsh enough, you will cause premature failure. Either slowly release the clutch to allow the syncros to match the revs without the jerking or rev match. If you do this every once in a while, then its not deadly, but if you do this at each shift, then you will need a new transmission in a year or two.

Rev matching leads to prolonged transmission and clutch life along with a smoother drive for the driver and the other occupants of the car.

Robin_NL · 04-19-2006, 09:41 AM

AND YES! Another thread about the manual gearbox, haleluja

wongmb · 04-22-2006, 08:01 AM

Why do you downshift from 5th to 3rd ? Your car will always jerk downshifting 5-3 unless you stay on the brake long enough to slow down to the proper rpm for 3rd gear. You hate the 4th gear and dont want to use it ??
If you need in a panic stop, both feet in !

And constant jerking will cause premature clutch failure

climkt · 04-22-2006, 08:08 AM

hi wong mb, u have to match your revs and your speed when u downchange. 5th to 3rd should be ok for most overtaking speeds from 80kmph to 120kmph. if your speed is too high and u downshift to 3rd gear, your revs will shoot up too high, not good for your car. at lower speeds, 3rd gear will be better than 4th for overtaking. guess u have to try different gears in your car at different speeds to assess for yourself. kinda like knowing your own human potential. that is the fun of manual boxes!

04-18-2006, 09:16 PM	#1
achtung Enlisted Member 3 Rep 30 Posts Drives: E90 Join Date: Feb 2006 Location: In a BMW iTrader: (0)	Driving a manual E90 Dear All My last car has a sequential manual gearbox that did all the blipping, heel/toe for me.... now on a manual E90 320i and have some questions. Not at the heel/toe or double declutch stage yet..... ... just trying to match revs and speed. Some questions: Will the following cause damage to my gearbox or prop shaft Revs lower than car speed (1) There are times when I downshift from 5th to 3rd on the highway and did not blip the throttle enough, so there is a jerk when I release the clutch. (2) When doing a quick get-away from the lights, while shifting from 1st to 2nd, release the clutch too quickly before there is enough throttle, there is also a jerk. Revs higher than car speed Of course there are times when I blip too much and engine speed is higher than the car's speed. There will also be a jerk I was thinking.... if the the driven wheels are going at a certain speed and it is not matched to the engine (or should I say gearbox) speed. The opposing forces will probably meet somewhere. My guess is it meets at either the prop shaft, the clutch, the gearbox or the engine. That is some major material stress right? What kind of wear will there be? Thanks Achtung Last edited by achtung; 04-19-2006 at 12:55 AM..
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04-19-2006, 09:14 AM	#2
stressdoc Moderator 618 Rep 10,855 Posts Drives: BMW i8; Toy 4runner TRD pro Join Date: Jun 2005 Location: Waco TX iTrader: (0)	It's a BMW. Have no fear.
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04-19-2006, 09:41 AM	#4
Robin_NL S0THPAW 8716 Rep 7,846 Posts Drives: HS M2 Competition Join Date: Apr 2005 Location: The Netherlands iTrader: (0)	AND YES! Another thread about the manual gearbox, haleluja
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04-22-2006, 08:01 AM	#5
wongmb Private 4 Rep 78 Posts Drives: 2006 325i SP Join Date: Sep 2005 Location: Markham, Ontario iTrader: (0)	Why do you downshift from 5th to 3rd ? Your car will always jerk downshifting 5-3 unless you stay on the brake long enough to slow down to the proper rpm for 3rd gear. You hate the 4th gear and dont want to use it ?? If you need in a panic stop, both feet in ! And constant jerking will cause premature clutch failure
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04-22-2006, 08:08 AM	#6
climkt Bimmer Manual all the way 66 Rep 1,811 Posts Drives: e90 320i manual Join Date: Dec 2005 Location: singapore iTrader: (0)	hi wong mb, u have to match your revs and your speed when u downchange. 5th to 3rd should be ok for most overtaking speeds from 80kmph to 120kmph. if your speed is too high and u downshift to 3rd gear, your revs will shoot up too high, not good for your car. at lower speeds, 3rd gear will be better than 4th for overtaking. guess u have to try different gears in your car at different speeds to assess for yourself. kinda like knowing your own human potential. that is the fun of manual boxes!
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