Launch question for a BMW 335i

[Joeybananaz18]

Hi guys. iv been lurking on the site a few times just looking for some info and i just registered a few minutes ago.

I always wanted a manual car and learned on my friend MK4 GTi. it was a 1.8t and anyone who's driven one know that little engine can move. iv always been a BMW fan, and my chance to get my first one came earlier this past summer- Saturday July 18,2009 to be exact. thats the day i took delivery of my 2009 335i coupe with a 6-speed manual, XDirive and the M Sport package.
I. Love. This. Car. I tell people i'll be totally cool if i never drive another car again.

Here's my question. When i learned on the VW, it seemed alot easier to get the car going. all i needed to do was let the clutch out until the friction point, and the car was off. with the BMW, i can do the same but i learned that i need to keep my foot on the clutch longer. the revs drop, i feel, too low, and the car feels like its going to stall right there. the launch is alot rougher too.
what i found works is bring the revs up to just around 1200, let the clutch out fast ( just until the friction point),and wait for the car to start moving. once the car gets going i take my foot totally as i continue to give it gas.



is this method bad for the cutch or any other part of the drivetrain?

[theholycow]

That sounds like a pretty barbaric technique. When you say "once the car gets going i take my foot totally as i continue to give it gas" are you letting your clutch foot up smoothly or just dumping it the rest of the way?

If your BMW is anything like my '08 VW 2.5, you do have to pause but you should still be smooth the rest of the way.

Your 2009 335i ought to have plenty of idle torque for launching at less than 1000 RPM. You may just need more practice.

[nothfx]

First, don't worry too much about your clutch. It's made to slip, and a little extra wear when you're just learning is normal.

Ideally, you want to be letting your clutch out in a smooth motion and slowly applying gas as your clutch engages. Your RPM's should be around the 1000-1300 mark (for my car/normal launch). This changes depending on how aggressively you're launching (faster launches generally go to higher RPM's), and how much power your engine has.

Your method isn't "bad", but you may be holding your clutch on the friction point longer than you need to (just get this impression from your description)

[Joeybananaz18]

i don't wanna sound like i'm flooring it or racing everyone i see. actually im very careful with it. sometimes i feel a bit too careful.

here i go step by step:
1. clutch in.
2. shift into first (foot still on clutch).
3. idle is probably around 700RPM.
4. bring up RPMs to about 1000-1200.
5. bring the clutch out until the friction point.
6. car begins to move forward.
7. from here on im letting the clutch out while applying gas.

i guess you could say i am dumping the clutch at this point, but is it really that bad if its already making contact with the gear?

thanks for your help guys.

[Joeybananaz18]

hey guys. i saw this thread.

viewtopic.php?f=6&t=11967

this is exactly what i do and how i drive my car. however i think i may take my foot off a bit sooner. i wouldn't call it "dumping" it. but i may be a bit faster. should i slow it down? i feel that it's just more time that my foot spends holding the clutch. If you guys think that the video in this thread is a good tutorial for beginers, i feel better.
i noticed his part about begining on hills. a really cool thing about newer BMWs that alot of people don't know about is their hill start assist. basically if you're starting on an incline, keep your foot on the brake and clutch and engage first. you can take your foot of the brake and the transimission will hold you in place for a couple of seconds or until it senses you're letting out the clutch. very cool feature.
thanks.

[VTECaddict]

just slow down your clutch release a bit. there's also a CDV, so it might throw off your rhythm a bit sometimes. i didnt have a problem with launching on mine, but rather shifting smoothly since the revs drop SO fast...you really have to bang out the shifts every time as if you're racing.

congrats on the car! are you on e90post already? your user name looks kinda familiar.

[theholycow]

It sounds like you're doing fine. Don't over-think it. Just enjoy driving.

[Joeybananaz18]

thanks for your help guys. believe me, i do enjoy every moment im with that car, whether it be driving it, washingit, or just looking at it.

yeah i am on E90post. same name. whats yours?

[fa22raptorf22]

Remember people, his beemer has a Clutch Delay Valve (CDV).

This means that It lets the clutch off slow no matter what you do.

You can almost dump it from anything above idle rpm.
I don't like the CDV's because all it does is burn the clutch to achieve smooth launches.

Side step the clutch at 5000rpm and see what i mean.

Edit:
Since he has a CDV, he doesn't have to do the conventional, come off the clutch till friction point and hold it there until the vehicle speed catches up to engine speed.

All you have to do with a CDV is come off it from the floor to all the way up semi slowly. No need to hold midway.

[theholycow]

I've never heard of a CDV. It sounds like a slight convenience that would complicate everything about maintaining, fixing, and diagnosing the car as well as learning to drive manual transmissions.

[fa22raptorf22]

I've never heard of a CDV. It sounds like a slight convenience that would complicate everything about maintaining, fixing, and diagnosing the car as well as learning to drive manual transmissions.

Really, a CDV was implemented my certain manufacturers in an effort to thwart the intentional abuse from any type of clutch dump launch.

It is removable, but essentially its a valve that limits the flow rate of hydraulic fluid, which in turn slows the clutch movement down.

Info:
One piece to remove:
http://www.zeckhausen.com/CDV.htm

[VTECaddict]

yeah i am on E90post. same name. whats yours?

same name there as well.

[NjSi]

Is it BMW's or Audi's that have that anti rollback feature ? /offtopic

[VTECaddict]

both probably do. its coming on more and more cars now.

[six]

Anti-rollback? Clutch delay valve? What the heck happened to the plain-old standard transmission?