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Old 04-04-2014, 03:15 AM   #19 (permalink)
jedi_sol
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Join Date: Mar 2009
Location: Tustin, CA
Posts: 929

2013 STi *SOLD* - '13 Subaru Impreza WRX STi
Subaru
Sports Cars
Team Turbocharged!
90 day: 26.59 mpg (US)

1996 Geo Metro *RETIRED from Ecomodding* - '96 Geo Metro Base
90 day: 58.68 mpg (US)
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I realize what you are doing wrong , holding the throttle at a steady 2000 rpm is not rev matching. That is the reason that car seems to JERK whenever you release the clutch. This is because at whatever speed you are traveling, 2000 rpm is either too high or too low. it does not exactly match the revs you need to be at that given speed that gear you select.

For example let's say you are traveling 60 miles per hour on the freeway.

In 5th gear their revs are at 2500rpm

In 4th gear the rev are at 3000rpm

In 3rd gear their ribs are at 4000rpm

In 2nd gear the revs are at 5000rpm.

Then if you are coasting in neutral let's say for example you want to shift into 3rd gear from neutral while driving 60 miles per hour you will need to Blip the throttle to 4000 rpm.

This is called "rev matching." You blip the throttle so that the engine rpm matches the transmission speed.

One way to practice this is every time you downshift, keep an eye on how far the revolutions increase between each gear.

Now go back to our example if you are driving 60 miles per hour in 5th gear then you down shift into 4th gear revolutions jump by 500 rpm then if you downshift to 3rd gear revolutions jump another 1000 rpm. Therefore if you are in 5th gear and you want to down shift to 3rd gear you need to blip the throttle so that the RPM's jump up 1500 rpm, then release the clutch.

Eventually when you get better you should be able to down shift through all of the gears and the car will not jerk. You will also be able to determine what the rpms need to be at for any speed and any gear.

Therefore as I mentioned in my previous post shifting smoothly is just something you will need to practice because you will need to get familiar with your transmission and engine and know how many RPM's jump between any given year at any given speed. trust me it just takes a lot of practice. Yes you can smooth things out by letting off the clutch a lot slower but then all you are really achieving is just extra wear on the clutch.

Try to find some YouTube videos on rev matching and how to downshift.

On my del sol that I owned for 10years, I knew the gear ratios like the back of my hand, I could drive it smoother than than an automatic transmission. Now I have a new car and It's annoying because I have to learn the new grear ratios all over again.
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Last edited by jedi_sol; 04-04-2014 at 03:28 AM..
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