guofuchen

I just got my new SLK 350 with manual transmission, i haven't taken any pictures, Iridium Silver with the Sport Package, very nice

question:

1. at what what rpm should I change gear?

thank you very much

joec1101

depends on what you're trying to do - if you're just normal driving (not racing), you can shift almost anywhere you want between about 2500 - 4000 RPM. If you're racing, you'll want to take it up to redline (I don't know what that is on an SLK350 - I'm gonna guess about 6000) but I wouldn't go above redline with a stock engine/drivetrain setup.

Ynot

Actually, b/c the max torque range is between 2,400 -5,000 rpm, you don't want to wait until close to redline to shift b/c when you get pass redline, the engine shuts off and really slow things down. I find shifting at 5,000-5,500 is optimum, in the max torque band and will yield the fastest times.

For everyday driving, I usually shift before 3,000 rpm, plenty of torque and fast enough for the road. I usually bypass fourth gear and go from 3rd to 5th, it's becoming a habit, don't know if it's good or bad but I'm getting 26mpg in the city.

Congrat's on your purchase, and enjoy your ride.

Easy-SLK

You need to take it just short of the redline before upshift. Around the 6100 rpm mark. Ignore duo comments, how many race drivers do you see short shifting unless they are winnning the race and in "cruise" mode

Sharp911

What about when comming to a stop do you down shift threw all the gear or drop it to neutral?

-1-

I love my six speed. When accelerating, depending on my mood, sometimes I used all six gears, sometimes just four. I doubt many would downshift through all six gears. That would get old real quick. I'm a firm believer in down shifting. Better control of the vehicle, much less brake wear and brake dust. Just my opinion.

SLK55AMG

Another comment regarding Ynots opinion...... if the fastest way to progress is as you say to change up early and not at the redline why does the 7G Sport program shift at the redline? peak power also plays a role in how quickly you progress so shifting early actually drops you to a place in the rev band (in the next gear up) that has lower power than if you waited and shifted closer to the redline.

e1000

the reason this dosen't work is that once you shift, you land yourself in a taller gear, therefore reducing the amount of torque multiplication through the gears.

To get the quickest acceleration, shift as late as possible in each gear.

Easy-SLK

FFS get an auto, its obvious you don't know how to drive. I think you are at the same level as YNOT

SLK55AMG

Take it easy Easy the guy is just asking advice.

bmwnomore

It always amazes me. We come to forums like this because we enjoy our cars and equally enjoy the exchange of information regarding all subjects even slightly related to them and there is always some ******* who shows no respect for his fellow enthusiast and makes a comment like the one above.

And the little stars weren't stars when I typed them.

mick1

haha. Who the heck would downshift through all the gears ???

bmwnomore

I have the six speed manual and downshift all the time. Depending on the speed, usually downshift through two gears like from third to second. Slows down the car without using the brakes too much.

SLK55AMG

A racing driver!

-1-

Yea, that's what I'm talking about.

Ynot

I agree, if you time it right, shift before redline everytime will yield the fastest times. I didn't make myself clear, assuming you are racing someone to 60mph, I've notice trying to time your shift before redline is difficult and if you miss it, the engine stops for a second, it's much easier to shift a little before redline. Maybe I need more practice

mick1

alrighty. I am going to exit the freeway, so I am going to downshift from 6th gear to 5th to 4th to 3rd to 2nd .... NOT

SLK55AMG

You asked who would downshift through the box....... the answer is a racing driver. Are you a racing driver? I'm not but that doesn't stop me heel toeing down the box when driving hard.

mick1

I think you mis-read my response to the question originally posed by Sharp911

I seriously doubt any respectable racing driver would downshift through all the gears to stop a car. He might downshift from 4th to 3rd when going through a corner but downshifting from 6th to 5th to 4th to 3rd to 2nd to 1st to stop the car is silly, to me. However, people can drive like that if they choose to do so.

Here's Sharp911's original question:

SLK55AMG

Slightly misread in that case...... if coming to a definate stop yes there is often no point in changing down through the gears....... in normal everyday driving I probably do the same as you.

However many (not all) racing drivers with normal manual shifts will usually downshift though the box as it puts less strain on the transmission and is smoother than skipping gears....... I could be totally wrong (I'm sure somebody will correct me if so) but I think this is even more important in race cars without synchromesh.

e1000

you said in your first post you should shift at 5.5krpms. You're then leaving 700 rpms of power in each gear. It may not matter 0-60 because the SLK350 needs a 2-3 shift before it hits 60 anyway, but over the distance you're losing a lot by shifting early.

A lot of people misinterpret torque curves and think they should land each gear in the meat of the torque band. The problem is, torque is multiplied by your gearbox. As soon as you grab a taller gear, you will be dropping much more torque than you would if you stayed in a shorter gear.

GDawgC220

I'd imagine when slowing down at a red light or stop sign, downshifting thru all the gears before stopping is much more wear on the clutch than using brakes. Brakes are much cheaper to replace than a clutch, imo.

Easty

If your trying to keep the car perfectly balanced you would use as many gears as you can. using the clutch to slow you down is engine braking a balance between engine braking and brakes is much smooth way to slow and the car is much better setup already in gear as you want to ease the brake and apply power. It's much more noticable on a sportsbike where the lowest revs you hot when racing it are 8k. not to upset the bike you want to be in gear as much as possible. and the faster more responsive cars are the same applies. check out the new gear duel clutch gear boxes. freecoasting or slowing down with the clutch disengadge aint a great way of driving.

I'd agree with Ynot if your driving in manual switch early, if the car has that much lb/footage it aint going to matter to much and hitting the limiter is a huge penalty. that's why I drive S mode on the track.

Pit-Pony

You downshift into the appropriate gear you would need to drive off after braking is done. No need to get into the gears you won't be accelerating under. If you're coming to a complete stop, it's best to put the car in say 2nd (after you have slowed) just in case you would need to accelerate away to avoid a mishap. Under these circumstance you would not even bother to let the clutch up as you come to a complete stop.

I hesitate to use the engine braking under normal conditions (except when descending a hill) as breaks are much less expensive than a clutch job or a miss shift.

The real danger is shifting unknowingly into too low a gear when accelerating. Say you put the car into 2nd instead of 6th from 5th under power and let the clutch out. If you follow through with this maneuver, good by engine if it revs well beyond the safe maximum it was designed for. A common way to destroy an engine for those young Honda street racers.

In any case, downshifting should be used to maintain speed down a grade or to get ready to move off after braking.

..jack

guofuchen

THANK YOU ALL FOR POSTING,

i have been enjoying my SLK350, going up and down of Highway 1, in CA.

So nice, btw, how do I post pictures?

thanks again