Gear Calculators

[Domesticated]

I made a gear calculator to compare the effect of different transmissions. Basically it takes tire size and gear ratios with final drive and shows engine speed vs vehicle speed shifting at a certain point. I can customize it to shows any gear at any engine speed. I took a few tire measurements and compared them to the actual tire size to get a common multiplier for tire diameter compared to the numbers on the tire. It seems close as my shift points in real life are identical to the graph. But regardless, it's like a dyno, not used to find exact numbers, but to compare differences ceteris paribus. So I can use any gear ratio coupled with and FD and tire size to get an idea or to compare what happens between changes within the same trans.

Here is what the output looks like: (Prelude Auto vs. MPT3 I believe)


And here is the code, it's a bit lame because it is code designed for a certain program and not universal (you know what I mean), but anyone who knows the main languages can figure it out just fine. You can adapt this to any program you want if your into coding. If someone can't use the code themselves I'll make comparisons for you. Takes about 30 seconds. Just list tire size, trans info, and shift point and I'll do the rest.

[mndude07]

Pretty cool. Any reason you didn't just do it in excel?

[Domesticated]

Lul, my freshman year an instructor said that Excel is a good program, but why bring a knife to a gun fight? This is much more powerful of a program. I figured for ease of use I would show it in this. I could have showed you my C++ code lol. With some ease should be able to transfer this code to Excel, it won't look as nice unless you know VBA for Excel. There are ways to get around it. Use my functions and do as you will with it in Excel. I don't mind. I just made this for my personal use, but decided to share. BTW, all the civil engineers I know still use Excel, I live with two of them, they call me help desk and use me to fix their Excel code. Haha, Mechies FTW.

[mndude07]

Lul, my freshman year an instructor said that Excel is a good program, but why bring a knife to a gun fight? This is much more powerful of a program. I figured for ease of use I would show it in this. I could have showed you my C++ code lol. With some ease should be able to transfer this code to Excel, it won't look as nice unless you know VBA for Excel. There are ways to get around it. Use my functions and do as you will with it in Excel. I don't mind. I just made this for my personal use, but decided to share. BTW, all the civil engineers I know still use Excel, I live with two of them, they call me help desk and use me to fix their Excel code. Haha, Mechies FTW.

Yes, ME's do win. I graduate in 2.5 weeks myself. I just like Excel for its ease of use. If excel can't do it, then I just jump right to matlab. Thanks for sharing, I'm sure some people will get good use out of it.

[Domesticated]

Jealous, I still have a bit of time left, but at least I have a job already. I like Matlab too, it closer to C++ and if you have the box it's great for data aqu in every day life.

[mndude07]

Jealous, I still have a bit of time left, but at least I have a job already. I like Matlab too, it closer to C++ and if you have the box it's great for data aqu in every day life.

Yes, having a job before you graduate is nice, I'm in the same boat. You ever use LabVIEW? I love it for daq.

[Domesticated]

No I haven't. My school doesn't have the best resources. I think I pay a little over 5k a year in tuition so we don't get a lot of different things.

[mndude07]

Too bad all the engineers on here can't get together and make a CB7 race car...

[wildBill83]

Is this assuming shift at 8k RPM? Isn't that a bit unrealistic for an F22A?

[Domesticated]

Lol, the only reason I got into school is because I quit street racing. I'm 24 and I don't graduate until Spring 14. If I were to build a racecar, it wouldn't be with a CB and no offense, but if I had to choose I would take more non engineers over engineers. The exception is people that were in the industry of building proper cars before school. I don't know too many engineers who know cars well. Even 90 percent of the engineers I know that work in the auto industry couldn't build a proper race car. I'm not trying to be rude in anyway, but the statement implies that engineers can build a better car and isn't necessarily true.

[Domesticated]

Is this assuming shift at 8k RPM? Isn't that a bit unrealistic for an F22A?

My H22A hits 8k every time I drive it

[badfish82]

Is this assuming shift at 8k RPM? Isn't that a bit unrealistic for an F22A?

Hahahah! Ive hit 8k on my f22....not so unrealistic, just really impractical!

This graph is sweet! Ive been trying too obtain this information for some time now without having too go out and do it to get the numbers.

[Fleetw00d]

BSME Univ. of Cincinnati 1981

Mechanical Engineers build weapon systems - Civil Engineers build targets.

[wildBill83]

OK, missed some of the OP about that I guess.

Cool stuff though. Do you account for the added mass of the A/T in the program?

[Domesticated]

OK, missed some of the OP about that I guess.

Cool stuff though. Do you account for the added mass of the A/T in the program?

Mass, this is just gears, nothing in here has anything to do with mass. The only thing I have't accounted for is slippage in the torque converter, but who cares, nobody is going to care about a few RPM. All the code is there, you can see exactly what I did or didn't account for.

BSME Univ. of Cincinnati 1981

Mechanical Engineers build weapon systems - Civil Engineers build targets.

Haha, for sure man.

Hahahah! Ive hit 8k on my f22....not so unrealistic, just really impractical!

This graph is sweet! Ive been trying too obtain this information for some time now without having too go out and do it to get the numbers.

Let me know if you need anything.