I searched but can't find this in another thread. In a stock Gen 2 MINI S, what is the best shift point to optimize 0 to 60 times. I don't know, but the seat of my pants tells me it's not 6500 rpm redline.

 

In all my various cars over the years, my butt dyno always seems to tell me felt that the best shift point is just past peak torque. Even though I know that 6500rpm is producing more power, somehow it feels different...almost like the engine is working too hard for the acceleration it produces. I wonder if a car would feel different @WOT if I had earplugs and earmuffs on!

That said, it wouldn't surprise me in the least if the fastest times are had by shifting just past peak horsepower instead. Or something - I don't know.

 

At redline a car is always going to make more torque than the next gear at pretty much any RPM. This is due to the gearing ratio.

First gear in an S is 3.31 plus the final drive is 3.65 (correct me if I am wrong here, I bowed to the internet for the numbers) meaning that you ultimate ratio is 12.08. That means you would multiply your torque by the ratio to find the ultimate amount of power you are putting to the wheels, so 200 ft-lb of torque becomes over 2,400. At redline you may have 150ft-lb of torque as the engine is wheezing, but that's 1,800 at the wheels. Now let's say you moved to 2nd gear (2.13 ratio, ultimately 7.77) and shift right into the peak of your torque (200), that's only ~1,550 ft-lb.

Obviously this is overly simplified but if you were to find a table of torque at every 100RPMs and then apply the numbers to them I think you would come out that it's best to stay in gear as long as possible.

 

yes. but then it all comes down to: would it be faster to accelerate that extra 1000 rpms to redline, or would it be faster to accelerate that extra 1000 from the bottom of a your next gear.

 

If you look at a dyno curve like, http://www.altaperformance.com/hardt...port-ecu-tuner

You will see that torque is dropping like a rock above 5500 RPM. So shift at 5500 ROM... or maybe a little later.

 

This is supposed to be a dyno curve for a stock R56 S.

 

another factor is "tach lag"

if i floor the gas in 1st gear and let it run into the rev limiter, the tach is reading about 6000 when i hit the rev limiter

so your shift from 1st to second has to take that into account

scott

 

Interesting because I've taken mine up to the 6500 redline at WOT and didn't hit the rev limiter.

 

As well as: launch control, or lack thereof. Many tenths leeway in a great launch or a lousy one that can detract from a good 0-60 time.

With the Corvette Z06 crowd, that's a common point of practice to be able to achieve the sub-4-second advertised ability of these cars. Of course, they can get to 60 in 1st gear...

Good discussion on shift points, I've been planning some experimenting anyhow as I hope to participate in the Texas Mile next year. It rewards speed attained in the mile, not so much the ET, but coaxing the best speed out of my car will benefit from good gearchanges.

 

If you shift at red-line, you will at least be close to optimum.

If you want, you can plot out torque at the wheels at each speed in each gear. That's six plots on the graph; you would shift where they cross--if they do. If they don't cross, shift at redline. Torque in gear is engine torque at that RPM multiplied by the selected gear and R&P ratios, and by the overall tire rolling diameter.

That assumes you can shift gears instantaneously, which is not the case. So it is usually better to go a little higher than those intersection points, because the car will lose a little speed (more at higher speeds!) during the time you are off the gas. (No, don't speed-shift. It is truly not worth it.)

That's all too much work for me, so I say just shift at redline.

 

I have spreadsheet which does that for me. Using the torque curves I've seen pictures of out there, you shift at redline in first and second. Its only once you get to third you start shifting before redline, when you're getting close to 90mph.

 

Yup, I've seen a spreadsheet like that as well. Still too much work for me. Plus trying to remember which RPM to shift in which gear... Red-line is much simpler, and is probably within a couple of percent of optimal anyway, especially when you account for how long it takes to shift.

 

he he he hehehe heeee...

 

Starting to beat a dead horse, but, no matter what you do, a Mini will never be a fast car 0-60... You want that, buy a Camaro, Mustang or a Corvette.

It's a little like taking a $2000/night hooker to the prom, you CAN do it, but there are much better uses...