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-   -   "RPM vs speed at each gear" table (http://forum.e46fanatics.com/showthread.php?t=949481)

MercForHire 10-09-2012 11:45 AM

"RPM vs speed at each gear" table
 
Hi is there any way to calculate the exact rpm for each gear at every speed with 10 km/h increments.
I want to make a table and commit that to memory so I can perfect revmatch each time.
I realize this table varies with different diff ratios. But any table would be a good start.

NOVAbimmer 10-09-2012 11:49 AM

www.bokchoys.com most likely has something

ac_2007 10-09-2012 12:12 PM

Plug in your gear and final drive (diff) ratios into Live For Speed (LFS), then drive the car on the simulated track using digital tachometer view.

Worked for me when I was wondering what highway RPM would be for my various cars.

Zell 10-09-2012 12:41 PM

Well, I don't have a table, but with a 3.07 diff, you can go by the following this "2k RPM" rule. It works pretty well for me and is really easy to remember. With the following, you'll be veeeery close to 2k RPM at these speeds in these gears (in an E46, that is):

1st, 10mph
2nd, 20mph
3rd, 30mph
4th, 40mph
5th, 50mph
6th, 60mph

shanneba 10-09-2012 03:25 PM

Quote:

Originally Posted by MercForHire (Post 14799689)
Hi is there any way to calculate the exact rpm for each gear at every speed with 10 km/h increments.

Yes, simple physics, diameter of tire times 3.14, take into account the transmission ratio and rear end ration....... convert your tire size units to miles.....

Or you could simply search Yahoo for "Speed in MPH calculation" and find this link: http://www.race-cars.net/calculators...alculator.html

or this one- http://home.netcom.com/~sgalaba/mph.htm

this one gives a table listing three gears: http://www.wallaceracing.com/gear-speed.php
..... SEARCH is your Friend!!

WDE46 10-09-2012 03:27 PM

QUOTE=MercForHire;14799689]Hi is there any way to calculate the exact rpm for each gear at every speed with 10 km/h increments.
I want to make a table and commit that to memory so I can perfect revmatch each time.
I realize this table varies with different diff ratios. But any table would be a good start.[/QUOTE]

Yes there are many ways to do it. I will do it right now since I'm bored. BRB

ZHPinthe103 10-09-2012 03:28 PM

Quote:

Originally Posted by NOVAbimmer (Post 14799699)
www.bokchoys.com most likely has something

this link is horrendous

MercForHire 10-09-2012 03:28 PM

They should have this table printed on the dashboard or something.

NOVAbimmer 10-09-2012 03:45 PM

http://www.bokchoys.com/differential/faq.htm

WDE46 10-09-2012 03:59 PM

1 Attachment(s)
I just made a nice table. It is setup for a 330Ci 5-speed manual with 245/40-17s on the rear wheels. You can put in anything.

https://www.dropbox.com/s/r1rxxal8mv...0vs%20RPM.xlsx

Use a wheel radius in METERS (you'll have to calculate that yourself). Unfortunately, the wheel radius changes with speed and load, so an average is the best I can do. Ratios are unitless by definition.

Attached a screenshot of the plot for those who are without excel.

Wow that used up exactly the time I had left until I leave work hahahaha.

DangerousMind 10-09-2012 04:03 PM

Quote:

Originally Posted by MercForHire (Post 14800420)
They should have this table printed on the dashboard or something.

I have heard of that before. Oh yeah, this guy had it: http://youtu.be/MZVrnd9V7sk

Mango 10-09-2012 04:14 PM

Quote:

Originally Posted by WDE46 (Post 14800508)
I just made a nice table. It is setup for a 330Ci 5-speed manual with 245/40-17s on the rear wheels. You can put in anything.

https://www.dropbox.com/s/r1rxxal8mv...0vs%20RPM.xlsx

Use a wheel radius in METERS (you'll have to calculate that yourself). Unfortunately, the wheel radius changes with speed and load, so an average is the best I can do. Ratios are unitless by definition.

Attached a screenshot of the plot for those who are without excel.

Wow that used up exactly the time I had left until I leave work hahahaha.

can you make one for a 3.38 diff. this one is the stock 2.93 i assume

MercForHire 10-09-2012 04:17 PM

Quote:

Originally Posted by WDE46 (Post 14800508)
I just made a nice table. It is setup for a 330Ci 5-speed manual with 245/40-17s on the rear wheels. You can put in anything.

https://www.dropbox.com/s/r1rxxal8mv...0vs%20RPM.xlsx

Use a wheel radius in METERS (you'll have to calculate that yourself). Unfortunately, the wheel radius changes with speed and load, so an average is the best I can do. Ratios are unitless by definition.

Attached a screenshot of the plot for those who are without excel.

Wow that used up exactly the time I had left until I leave work hahahaha.

Thanks so awesome :thumbup::thumbup::thumbup::thumbup::thumbup::thumbup::thumb up:

MercForHire 10-09-2012 04:27 PM

1 Attachment(s)
here is teh metric table.

WDE46 10-09-2012 04:57 PM

Quote:

Originally Posted by E46Mango (Post 14800547)
can you make one for a 3.38 diff. this one is the stock 2.93 i assume

You can edit the file. Just change the final drive ratio value. Maybe I should have just put that as Diff ratio.


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