low rpm very shaky?

[raywong]

let say my car is rolling slowly on 2nd gear, 1600rpm... If I floor the throttle now, the car will accelerate from 1600-2000rpm in less than a second, but it is shaky. It smooths out after 2000rpm. It feels like a loss engine/trans mount, or engine miss fire. This only happen in low rpm(under 2000), and in higher gear. Is this normal?

[Erhan]

Not sure if it is normal. IIRC, the S65 gives 85% of peak torque starting from 2krpm. Could be related to that?

[radiantm3]

My car tends to buck once in awhile at very low RPMs when the engine is not warmed up all the way. It's a bit embarrassing when it happens in a parking lot with people around because it looks like I'm just learning to drive a manual.

[sensi09]

The shaky feeling like the car is about to stall? Shift down

[mdosu]

are you doing this right after you start the car up? it might be a cold transmission/clutch.

I have a 6 speed and right after i start the car up cold, when I drive and put it in 2nd gear, there's some jerkiness in low rpm ranges, after the car warms up, it's all smooth after that.

[JoLo]

Yup, i have a 6spd and when the engines cold it is very jerky at low rpm's.

[ChrisK]

Same here - a little rough when she cold. OP, sounds normal to me.

[sameh]

Can you try same thing on MDM or DSC off and report back. I have a feeling it's related to DSC interference once you floor it (as you said).

[Grail05]

normal

EDIT; normal for 6MT.. not sure on DCT...

[mot]

post #6 and #9 are spot on

[1sikbmr]

Sounds normal to me... 6MT is always jerky at start

[AngelinIsRich08]

Kinda off-topic but I'm thinking of buying an E90 M3 and was wondering if it's ok to redline the car in 2nd gear. I know that redlining in 3rd will easily make me pass most speed-limits but since I don't track I'm still hoping to be able to fully experience this NA engine's genius.

[quackman]

Originally Posted by AngelinIsRich08

Kinda off-topic but I'm thinking of buying an E90 M3 and was wondering if it's ok to redline the car in 2nd gear. I know that redlining in 3rd will easily make me pass most speed-limits but since I don't track I'm still hoping to be able to fully experience this NA engine's genius.

What do you mean by "ok"? Legally? well, it redlines 2nd gear at speeds reaching like 70 so... legal enough

As far as its being ok for the car, well yeah it's fine. And it sounds, feels, etc. AMAZING on the M3. Just don't bounce it off the rev-limiter like a maniac and it's cool.

[raywong]

thanks for the response guys.
My car is 6mt.
it's rough regardless cold or warm.
It is not very noticeable, girls calling me paranoid.
It is more noticeable if road has incline.
It happens on 3rd gear too.

[Vise]

Originally Posted by JoLo

Yup, i have a 6spd and when the engines cold it is very jerky at low rpm's.

Same. This has been discussed before a few times too, appears to be fairly normal behaviour.

[Radiation Joe]

My guess is you have about 20k to 25k miles on the car. Replace the spark plugs and it will fix it right up. I'm on my second e90 and both have had this behavior, especially when cold. It got worse until around 30k miles when the plugs were replaced. After that it was fine.

[JCtx]

Nobody has called you on this, but flooring the throttle at 1,600 rpm is crazy man. You're wearing/beating/lugging the crap out of your engine man, and it's bucking in protest. And yes, bucking under light throttle and lower rpm when cold is normal for this engine. You need to run a bit higher rpm in 1st, then give it a bit of throttle in 2nd and it doesn't buck. After engine is hot, it's always smooth in my case. Do it wrong, and car is going to buck like a bronco .

[mdosu]

Originally Posted by Radiation Joe

My guess is you have about 20k to 25k miles on the car. Replace the spark plugs and it will fix it right up. I'm on my second e90 and both have had this behavior, especially when cold. It got worse until around 30k miles when the plugs were replaced. After that it was fine.

are you saying it's a spark plug issue? or are you saying it's cold transmission issue? B/c most of us attribute it to cold transmission.

[edcvin]

6mt here with bucking on cold tranny..I would say its normal.



-Vin

[1sikbmr]

Originally Posted by elp_jc

Nobody has called you on this, but flooring the throttle at 1,600 rpm is crazy man. You're wearing/beating/lugging the crap out of your engine man, and it's bucking in protest. And yes, bucking under light throttle and lower rpm when cold is normal for this engine. You need to run a bit higher rpm in 1st, then give it a bit of throttle in 2nd and it doesn't buck. After engine is hot, it's always smooth in my case. Do it wrong, and car is going to buck like a bronco .

+1

[raywong]

Originally Posted by Radiation Joe

My guess is you have about 20k to 25k miles on the car. Replace the spark plugs and it will fix it right up. I'm on my second e90 and both have had this behavior, especially when cold. It got worse until around 30k miles when the plugs were replaced. After that it was fine.

Just want to report back here. Joe was right on, after replacing all plugs(tips worn out), the idle is so much smoother, huge low end power gain, very solid acceleration when I floor it at 1500rpm, cold or warm.
everyone should test their low end performance at 25000 miles, change your spark plugs if any of the above symptom exists.

[GIdriver]

Originally Posted by raywong

let say my car is rolling slowly on 2nd gear, 1600rpm... If I floor the throttle now, the car will accelerate from 1600-2000rpm in less than a second, but it is shaky. It smooths out after 2000rpm. It feels like a loss engine/trans mount, or engine miss fire. This only happen in low rpm(under 2000), and in higher gear. Is this normal?

Sounds normal to me. I believe there's a thread in this forum on e9x M3 noises an rattles. You might want to search for that.