Transmission ratios & acceleration

[Walter Moore]

I have an '82 tranny with a 3.7 and its a great combo. Walter, with that combination you have I'd imagine you are doing very low rps's on the highway. Out of curisouity what kind of mileage do you get if you keep it around 60-65 mph?

Well I get about 25 mpg on the highway at the speeds that I normally drive

As for the fuel mileage at 60mpg... I will have to get back to you on that...

With the L24 60 mph is about as slow as I can go in 5th. It seems like 80 mph is around 3K RPM, but I don't recall if I have ever gone that fast.

[robftw]

I've seen a similar tool but it doesn't plot the numbers. Is that one available on the web?

There is something odd about your attached picture though. Maybe you didn't redraw after putting in new numbers. 3rd gear plots the same line but 4th gear doesn't even though the values are the same for 3rd and 4th, between the two transmissions.

Anyway, I wouldn't mind a link to the site if you have it.

http://fatboyraceworks.com/gears/

[robftw]

I like this one a lot better.

Does not work

[LeonV]

Does not work

Strange, works for me, on different computers even.

[robftw]

Strange, works for me, on different computers even.

I get this on all my browsers... hmm maybe im missing an addon.. does it use flashplayer? or something else

noscript is also disabled...

[LeonV]

Pretty sure it's not flash, but I'm no software expert. You must be missing some sort of driver/codec/application/???. It works on Explorer and Firefox on my work and home computers.

[jmortensen]

I think it's Java. I was looking at making something similar for my differentials website. I have a calculator up and running, but in a non-graphical form. Having the graphics really helps to see that 2-3 shift gap, and the calculator that Leon suggested is really the best one I've seen.

FWIW, I once GAVE my friend a close ratio transmission after we went to the track together, and I just walked away from him after shifting to 3rd. He had a wide ratio box and his L18 with Mikunis just fell on its face when he hit 3rd because the rpms dropped too low. We both thought we would be battling it out on the track, but due to the gear ratios it became no contest at all and wasn't nearly as much fun.

[robftw]

I think it's Java. I was looking at making something similar for my differentials website. I have a calculator up and running, but in a non-graphical form. Having the graphics really helps to see that 2-3 shift gap, and the calculator that Leon suggested is really the best one I've seen.

FWIW, I once GAVE my friend a close ratio transmission after we went to the track together, and I just walked away from him after shifting to 3rd. He had a wide ratio box and his L18 with Mikunis just fell on its face when he hit 3rd because the rpms dropped too low. We both thought we would be battling it out on the track, but due to the gear ratios it became no contest at all and wasn't nearly as much fun.

It was java, i forgot to reinstall it after i reformatted my machine.

Also since you are the diff. man here would it be smarter to get a 3.9 instead of the 4.11? i don't care much for highway speeds or gas mileage

[jmortensen]

It's a personal choice, but the difference in rpm from the 3.9 to the 4.11 is like 150 rpm at 70 mph. Depends on what tire size you use, but it's not going to be night and day. I personally would go for the 4.11, and if you have an LSD 4.11 already, that's even better.

[robftw]

It's a personal choice, but the difference in rpm from the 3.9 to the 4.11 is like 150 rpm at 70 mph. Depends on what tire size you use, but it's not going to be night and day. I personally would go for the 4.11, and if you have an LSD 4.11 already, that's even better.

It is an lsd. its actually the front diff from a patrol. Do you know where i can buy the transmission gear for the speedo? I don't know of any car that came with it from the factory in the rear end..

And i will be keeping my tires the same, i will probably be using a 235 60 R14 tire for daily driving, maybe a 235 50 R14 DOT drag tire.

[jmortensen]

Tried Nissan?

[robftw]

Yep, called 3 dealerships and they couldn't get one.