[billgti]

hey everyone, i just want to share my thoughts on the 325 manual i testdrove this weekend. i drove the auto earlier and i thought the shifts were quite quick and smooth but i'm really a manual guy so i decided to try the manual. i must say my expectations were quite high after hearing all the praises for bmw's gearboxes (especially coming from a vw gti vr6 which has a very uninspiring shifter). however, i noticed that there's a noticeable jerk once u step on the clutch / release the gas to change gears. i'm not talking about the clutch takeup..that was no problem...it's the stuff you do right before you shift the shifter. anyone else share the same experience?

[CC 330i]

I know what you mean. I think it mostly has to do with the CDV (clutch delay valve) that is supposed to "soften up" clutch response, but basically makes the car harder to drive for good drivers. This can be removed or altered though.

I got a tip from someone here that works well, though. I found that if you start trying to move the shifter before you actually press in the clutch, it smooths out the shifts. It's weird the way it works, but it does for some reason. I think it has more to do with timing than anything.

I have found that I am getting used the the clutch and shifting on the 330i after a month or so, but I also came from a Jetta VR6 GLX, and the shifter actually felt a little better in that car, but I was used to it I guess.

[silverado]

Originally Posted by billgti

... however, i noticed that there's a noticeable jerk once u step on the clutch / release the gas to change gears. i'm not talking about the clutch takeup..that was no problem...it's the stuff you do right before you shift the shifter. anyone else share the same experience?

I do not understand the kind of jerk you're describing that happens before you shift. Was it not something that could be fixed by varying the timing between clutch press and gas let up?

[billgti]

Originally Posted by silverado

I do not understand the kind of jerk you're describing that happens before you shift. Was it not something that could be fixed by varying the timing between clutch press and gas let up?

in my 15 min test drive, it seemed like at lower revs there was less of a jerk. whenever i brought it up to 5000+ rpm and tried to upshift, once i let off the gas and step on the clutch, the cars jerks. it's not a big jerk but it doesn't happen on my gti or other cars i've driven recently (integra or mini cooper s) so i was just wondering if anyone else experienced this b4.

[CC 330i]

Originally Posted by silverado

I do not understand the kind of jerk you're describing that happens before you shift. Was it not something that could be fixed by varying the timing between clutch press and gas let up?

If I am right about what it is, you are right, it can be fixed by varying the timing, but it's hard to get used to a CDV car when your old car didn't have a CDV. I test drove a lot of Audi S4s prior to buying my car, and it was nearly impossible to get a smooth 1-2 shift, and everyone on the Audi board complains about this. I think Audi must have some type of CDV also. It's hard to get used to "outsmarting" a Clutch Delay Valve.

[billgti]

CC 330i, thanks for your reply. i did a search just now for CDV and did some reading on it. looks like that might contribute to what i am feeling. i've been driving stick for a long time now but i admit that it takes me time to get used to different manual transmissions. i guess i'll have to test drive again and see.

just as a side note, i was expecting the clutch to grab quicker (closer to the floor) and the throws to be shorter. it seems like my friend's audi a3 has a nicer shifter and clutch take up.

[CC 330i]

Originally Posted by billgti

CC 330i, thanks for your reply. i did a search just now for CDV and did some reading on it. looks like that might contribute to what i am feeling. i've been driving stick for a long time now but i admit that it takes me time to get used to different manual transmissions. i guess i'll have to test drive again and see.

just as a side note, i was expecting the clutch to grab quicker (closer to the floor) and the throws to be shorter. it seems like my friend's audi a3 has a nicer shifter and clutch take up.

I drove the A3 too and I agree. Hate to say it guys, but the Audi clutches and gearboxes are smoother in the A3 and A4 than they are on my E90 330i. The 1-2 shift on the S4 was a little hard, but overall that gearbox was better too.

I have always had a manual transmission, and just today I drove my friend's Porsche Boxter S to lunch (she wasn't feeling well enough to drive herself and felt bad that I always drive my car to lunch ). I was noticing how much more direct the Boxster tranny is, and how much more intuitive that it is. I am able to get smooth shifts easily on her car, but maybe that is because it has 50K miles.

I have driven everything from a Boxster S to a fully loaded Forest Service 4x4 Fire Engine (with split-shift 10 speed manual transmission like a semi), and I have to say that the E90 is one of the hardest cars to get a smooth shift on that I have ever driven. Heck, my 1973 Bronco was easier to shift smoothly, and if you didn't get that clutch right, it hopped badly. I drove the aforementioned 4x4 Fire truck over most of the Western US, including Sonora pass which is one of the steepest, windiest roads in the West, and never had a problem. Not that I had a problem with the E90, but it is just different.

All that being said, I CAN shift my E90 smoothly, but I just have to really CONCENTRATE sometimes. It's no biggie, but it's kind of odd. Plus the throws on the E90 (and E46 for that matter) are fairly long. Much longer than on my Jetta GLX even. It's weird.

[silverado]

CC 330i,

While I don't have a problem with jerking in the first half of the shifting process, I agree about how hard it is to shift smoothly in the E90. I swear everytime I think I got the hang of it by having a perfect trip where all my shifts are wonderfully smooth, the next time around I'm having a heck of a time shifting smoothly and having to concentrate to get it right. It's quite odd.

I learned to drive using manual transmission and drove MT cars for about 10 years then swithced to automatic about 10 years ago. I consider myself good driver and never had problems adjusting to a new car with manual transmission. Now I'm happily back to MT land in my main car, but I kept attributing the problems above to possibly being out of practice, but now I'm thinking that might not be the case.

I wonder how they expect the non-experienced driver to shift that the CDV is helping them? I would shift that way myself if it could yield consistent results.

[CC 330i]

I think the CDV is mainly there to soften driveline lash and harshness to make the car feel less "jerky" but it often provides the opposite effect I am afraid, because the clutch action lags behind what your foot is doing.

I have heard that the CDV also increases clutch wear because it does not allow the clutch to engage as quickly. (it slips more). I understand that max performance take-offs suffer the most, and I haven't had the opportunity to make a max performance 0-60 run yet to test this out. I hear the clutch slips a lot though due to the CDV.

I may put in a modified (basically disabled) CDV when I get the chance. There is a person that supplies these on this board or another one.

[skimo]

Guys this is exactly what I noticed and i was trying to explain in this post:

http://www.e90post.com/forums/showpo...6&postcount=32

I thought it had to do with the hesitation, but I could swear that something is fishy with this tranny. I have never driven an auto - except for rentals, and the e90 is embarassing me. there seems to be this gap, and after you recover is when the jerk happens.... ill do my best to explain in own words...

Time (ms) || Action
0 || press clutch
80 || release gas
200 || shift gear
800 || relase clutch
1200 || press gas
1500 ||GAP !!
1500 ||Jerkk..
1700 ||drive...

I feel like I release the pedal, but the "contact wheels" are not touching! I have to like give it an istant to engage ! Like there is a delay between me pressing the pedal and the tranny acutally obeying my commands ! Now i learn there is this CDV?

I am sure people here would like to here comments from those who have removed the CDV...

Thanks
Skimo

[billgti]

Originally Posted by skimo

Time (ms) || Action
0 || press clutch
80 || release gas
200 || shift gear
800 || relase clutch
1200 || press gas
1500 ||GAP !!
1500 ||Jerkk..
1700 ||drive...

during my testdrive, i experienced a jerk before 200ms...i haven't experienced this in any other cars.

i got the jerk at 1500 at first...but that was just me not used to the tranny...seems like it's a timing issue due to CDV but the shifts were smooth as long as i gave it enough gas...

i'm still wondering about the jerk before i even shift gear..

[Dani]

I had some trouble with smooth shifting when first getting my E90 as well. I came from an integra. Instead of worrying about the timing of the clutch on your shift try changing the timing of the gas. I found that my E90 likes more gas in a shift than most cars.

[borahatch]

Originally Posted by Dani

I had some trouble with smooth shifting when first getting my E90 as well. I came from an integra. Instead of worrying about the timing of the clutch on your shift try changing the timing of the gas. I found that my E90 likes more gas in a shift than most cars.

Yes, I noticed this too. I took my sister's E90 (325i with all the goods) to get tinted today and I noticed it took a lot of gas to get things smooth. I'm used to my G35 which has a much shorter and more direct feel/action.

[silverado]

I have found that an alternative to more gas is shifting faster and/or shifting at a higher RPM. The jerking happens to me more when shifting at lower RPMs or shifting slowly. When shifting at lower speeds it pays to hold the clutch a bit at the top of your stroke as you're releasing the clutch.

[bimmy]

There is similiar issue on my Alfa 156, but when you get used to it's not a big problem any more. But i agree you have to be concentrated if you want to change gears without jerk.

[F32Fleet]

2 things that are different from your VW. #1 weight #2 rwd . The E90 is much heavier than your VW. #2 RWD - because power is coming from the rear, you feel a shift forward when that power is taken away. Take that with a heavier car and you will feel it more. As for the CDV, well BMW clutches last for 150k miles for a reason. The CDV makes the 1-2 shift difficult sometimes, but you save on clutch wear. Just a thought.


My E46 shifts much smoother @ high rpms. Come to think about it, the car is much more fun to drive at high rpms (4k+).

My previous car was a Jetta 5spd.

[Black325i]

While I cannot comment on exact millisecond intervals, I do agree that the shift process is much smoother (at least for me) at higher revs. As noted above, this is also more fun and IMO, how the car should be driven.

I did not buy a "performance" inspired car, to shift at ~2,500 RPM.

[romeo26]

hay socom
bmw clutches last well over 150k miles my e30 has close to 250k miles and still has the originol clutch. and i dont think my car has a cvd!!!
why cant bmw just take out the cvd?

[F32Fleet]

Originally Posted by romeo26

hay socom
bmw clutches last well over 150k miles my e30 has close to 250k miles and still has the originol clutch. and i dont think my car has a cvd!!!
why cant bmw just take out the cvd?

Isn't that the truth. Maybe they think since most of their cars are leased, they won't have to replace clutches on CPO cars?

[skimo]

Originally Posted by skimo

Time (ms) || Action
0 || press clutch
80 || release gas
200 || shift gear
800 || relase clutch
1200 || press gas
1500 ||GAP !!
1500 ||Jerkk..
1700 ||drive...

Just wanted to add the the MS timinings I have are by no means exact and are only to be used as a reference for comparison between each other.

Another thing, I did notice that shifting is easier at high rpm (or when you just dont release the gas as much when u shift.) But I am still in the break in period

Skimo

[silverado]

As I think about this I can now see how this is caused by the CDV. Just as the CDV prevents the quick transfer of high revs from the engine to the gearbox when starting, it is preventing the quick transfer of revs from the gearbox to the engine. If you're shifting and let the rpm fall below the matching rev of the current car speed and your next gear, the engine will eventually be brought up to the proper rev by your stepping on the gas and, if you don't give enough gas, also by the transfer of revs from the gearbox. In cars without a CDV, if you don't give enough gas quickly enough after a shift, the transfer of revs from the drive train to the engine will happen quickly which makes the lack of throttle-based revs harder to notice. With the CDV, however, the transfer will be delayed, which means that you will feel the jerking a lot more.

This is why shifting from higher gear (or giving enough gas to essentially rev match) works fine because the engine and the gear box will be rotating at almost the same speed from the beginning.

[Cloud9]

Originally Posted by CC 330i

If I am right about what it is, you are right, it can be fixed by varying the timing, but it's hard to get used to a CDV car when your old car didn't have a CDV. I test drove a lot of Audi S4s prior to buying my car, and it was nearly impossible to get a smooth 1-2 shift, and everyone on the Audi board complains about this. I think Audi must have some type of CDV also. It's hard to get used to "outsmarting" a Clutch Delay Valve.

I have about 250 miles on the car since I picked it up Friday night. First of all, I love the car! I thought the jerky shift from 1-2 shift was just the break in period. I really have to think about my shifting to get a smooth shift. Driving at higher speeds 40+ the shifting is smoother. I also own a VW golf with a manual and I can go through the gears very smoothly. Even my friend commented how I seem to have a harder time with the E90.