I hate to admit this in public, but think I need advice and/or help...
I've driven various stick shift cars for about 25 years, and I'm fine in my old GMC truck, but I bought a 2000 Z3 2.3 a couple of weeks ago, and I'm not happy with my shifting.
This is my first "sports car", and I can't seem to get the hang of consistently smooth shifting.
I'm frequently jerking the car around when shifting, can't seem to get the hang of synching rpm/vs. releasing the clutch.
Are there any tricks to this, will it just get better with time and practice, or might there be something wrong with the clutch?
Before I bought the car I took it to Allspeed (an import specialty shop in Peachtree City, GA) for an inspection, they said the car is in good shape, didn't mention anything about the clutch/drivetrain.
I'd appreciate any helpful suggestions.
TIA Mike
Mike Patterson Please remove the spamtrap to email me. "I always wanted to be somebody...I should have been more specific..." - Lily Tomlin
There could be something wrong with the clutch, but I suspect you just need more practice. You're used to the ratios in yoiur truck, but your car is a completely different animal. I drive a Jeep CJ5 with a transmission from an old ('64) Ford truck, if I drive the Jeep for any length of time and leave the BMW in the garage, then I also shift poorly when the Bimmer comes out. The technique is different on the two vehicles, and if I shift the car the same way I shift the Jeep, then the ride is not as comfortable as I would like.
You could be having trouble with the drivetrain, and you need to figure out if it's you or the car. My moiney is on the notion that it's you.
Another option, check to see when your transmission fluid was last changed. If its been about 30,000 miles, then change it and use a good synthetic fluid like Redline or Royal Purple. Changing to a good synthetic really made a difference in smoothing out the shifting in my car.
Other than that, perhaps you should have another person, who is experienced in driving stick, drive your car. Perhaps a good BMW independent to see if there is something wrong.
My first question would be: "Does the 2000 Z3 have a clutch delay valve?" That's usually the issue when someone new has trouble shifting a Bimmer. epbrown
What rpm do you shift at? I find it quite hard to shift my 97 328 smoothly at
3000 rpm, for example, because the rpm for the next gear is just too low for the engine to pull, and for nice clutch hookup. I find that there's a 'rhythm' to any car where synchros, clutch, flywheel weight, etc. all work together to produce smooth shifts. Nice tight synchros (what you want) can 'seize' when shifting at low rpm, for example. This is also what happens when trans oil is cold. My 68 'cuda with a new process
4-speed, and real tight synchros, used to let the trans oil cool enough on a long freeway drive in
4th gear [direct drive] that it was just a 'dog' to shift during the first mile off the freeway. You could shift that big ol honkin V8 at 2000 rpm, though, and it would pull nicely at 1500 in the next gear.
With my 328, the 'rhythm' occurs when shifting at 4000 - 4500 rpm for each gear. When you shift, a slight pause before letting the clutch back out lets the rpm drop to the rev-match point of between 2500-3000 rpm for the next gear. Even if you are off slightly, (try to stay on the high side, for minimum drive train lash) there is now enough momentum in the flywheel that clutch hookup is generally smooth as glass. Now note that the 1-2 shift is the toughest, because the ratio between the gears is so high. Successive gears get closer together, so your rev-match point moves up in rpm as you move up through the gears. Also note that as you shift at higher rpm, the pause to wait for rev-matching decreases. 5000-5500 rpm 2-3, and 3-4 shifts when entering a freeway, for example, go pretty much as fast as you can go - should be smooth as glass, and are just a blast.
One other tip: Make sure you push the clutch in FIRST before letting off the throttle. If you back off the throttle just before your shift (something almost intuitve to do) you throw the drive train backwards against all the slack in the mechanism leading to lash and a jerk when you let the clutch out in the next gear. This is tricky - timing is critical, and I find that if I miss a shift, slightly, I start to 'flinch' on the next ones and end up backing off on the throttle more - gets to be a viscious circle.
Final thought. Do you have the clutch delay valve on your car? I do not have this on mine, so if you do, maybe my suggestions won't work very well - dunno, as I've never driven a car with a delay valve on it.
It appears that you have discovered the infamous BMW Clutch Delay Valve which makes it very difficult to learn to operate the clutch in your car. It imposes a restriction in the hydraulic line so that the clutch cannot be released at more than a specified rate. For many people this means overreving the engine while the clutch is taking it's sweet time engaging. There are some aftermarket fixes for this questionable device but it is probably easiest to take it out and knock the check valve out of it. Here's a link to one of the aftermarket sources.
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And here's what they have to say about the valve. Sound familiar??
Several models of BMWs with 5-speed or 6-speed manual transmissions have a Clutch Delay Valve (CDV) installed by the factory. This valve is the culprit behind the jerky shifting that makes your BMW hard to drive, even if you have been driving a standard transmission all your life. When replaced with the Zeckhausen Racing modified CDV, your clutch is suddenly transformed into the smooth, easy to modulate clutch that should have been delivered from the factory as standard. Extend the life of your clutch and increase the enjoyment of your BMW driving experience today!
I'm pretty sure that when the OP was talking about smoothness of shifting, he meant the "de-clutching" part, not the actual shifting of gears. Based on that, I don't see how chaning the gear oil is going to make anything smoother, but I do agree with you that the "notchiness" that is felt in some BMW manual gearboxes can be alieviated by changing to a better gear lube.
For the de-clutching smoothness, I think it is just a matter of getting used to the car. The engagement point on each of my cars is a bit different. Just switching between our '95 325i and the '97 Z3 takes a while to get used to the difference and those are both (under the skin) the same cars (E36's).
Well, I can see shifting at 4000 rpm (or even higher) when driving briskly, but for just putting around town in traffic I have no problem shifting at 3000 - 3500 smoothly. YMMV
I routinely -- that's ALWAYS, except for Special Occasions -- shift at around 2500, depending on traffic conditions. Why carry any gear to 4000 RPM when traffic is creeping along at speeds below 40 MPH?
I agree. I use 2,700~3,000 (unless in a real hurry) and my clutch feel is as new after 70,000 miles. The low end torque of the 2.8/3.0 sixes makes this easy.
I was pretty sure that many would consider me weird, or crazy. But really, you, Fred, Tom, and Dave should give higher shift points an honest try. If you still don't like it - well ok.
As I mentioned, I used to shift other cars much lower, but a big V8 with twice as many 'cubes' and "close ratio" tranny is a totally different beast than a small (to me) I6 with a "wide ratio" (even wider than my 4000 lb truck) transmission. To me, as an engineer, the wide ratio of the BMW transmission suggests that it was actually designed for high rpm shift points, and once I tried this technique, it really turned out to be the "sweet point" for driving the car. A few points that are important:
Shifting at 4000 rpm doesn't mean you're in a hurry. Your haste depends upon throttle opening - not shift point. I'm virtually always beaten off the line at traffic lights, unless I don't want to be.
Driving in lower gears, so engine rpm is 2500 or higher for any steady cruising speed takes advantage of the wide operating range of the engine. You shift much less frequently, you're always in an appropriate gear to accelerate quickly if you have to, or to slow down and pull in behind someone, for example, without having to shift down - i.e.you have a relatively wide operating range both above and below your current speed using the current gear.
Traffic jams are MUCH easier to live with. Just crawl along in 1st gear as traffic speed varies from 5 - 20 mph or so. Why shift? You save clutch, synchros, brakes, and your left leg. Again, the wide operating range of the engine - I mean, I'm truly hooked on this. Taking advantage of it makes the car such a joy to drive in so many situations.
As I mentioned in my first post, the flywheel weight, synchros etc seemed to be designed for shifts at higher rpm. Sure, I can shift smoothly at low rpm, but it is MUCH easier at higher rpm. My synchros are still tight at 124K miles, and in fact want to seize with low rpm shifts and cold transmission oil. Shifting at 4K warms up the oil and then it's just like soft butter - marvelous. You want to drive around more just for that "feel" of shifting gears.
There's more, but I'm getting long winded. A comment about fuel mileage in case anyone wonders. My average is 20 mpg around town, and 28-29 highway (at 80 mph)
- right at the EPA numbers for the car. Not the only thing, but an important factor in fuel mileage (according to my engine design text) is running the engine so that piston speed is roughly around 1600 ft/min. Guess what 3000 rpm is - 1655 ft/min. This number also tells you that 3000 rpm is a "no brainer" for the engine - it can run forever at this speed with virtually no wear.
It's not that I don't like them higher, I get no benefit from them in daily driving. When I want spritited driving, I certainly go for the higher revs, but when I'm on my way to work or to the corner for a gallon of milk, I just can't get the revs that high and still maintain any semblance of reasonable fuel mileage.
The OP was looking for smooth shifts, and my humble experience is that smooth shifts come at the lower end of the RPM spectrum.
I agree with that point. Except, I generally try to stay in 2nd as much as I can, and even try to stay in 3rd. When the cars in front begin to slow, I let off the gas and stay in 3rd as long as I can, then if the cars completely stop, I have to shift to 2nd or 1st, but if they start moving again I can remain in 3rd until I get to about 75 mph, give or take a bit.
Sure. My synchros were in great shape on my other car with 220k miles on it.
My mielage on my old car was like that, but the convertable that I have now doesn't seem to come close. I guess the convertable platform weighs so much more ...
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