Crawl Ratio??

[Wisha Haddan H3]

The torque converter has a multiplier value depending on RPM, but 4x seems high. I have seen numbers between 1.5 and 2 for some auto trannies.

For example, the H1 torque converter ratio is 2.2:1, according to this link http://www.kellyhummer.com/h1.htm

[PARAGON]

Originally Posted by Wisha Haddan H3

The torque converter has a multiplier value depending on RPM, but 4x seems high. I have seen numbers between 1.5 and 2 for some auto trannies.

For example, the H1 torque converter ratio is 2.2:1, according to this link http://www.kellyhummer.com/h1.htm

Ok, so.......

[Wisha Haddan H3]

Does anyone know the multiplier value of the H3's 4L60e? I'm curious about the torque multiplier curve too ... at what RPMs do you get the most out the converter?

[PARAGON]

Originally Posted by Wisha Haddan H3

Does anyone know the multiplier value of the H3's 4L60e? I'm curious about the torque multiplier curve too ... at what RPMs do you get the most out the converter?

wouldn't a better question be "when does stall occur and lockup occur?"

[f5fstop]

Every equation I have ever seen for a crawl ratio has never taken into account the torque converter. Reason is it is next to impossible since the converter slips at a different rate at different engine rpms. Therefore, the calculation would be next to impossible. You would have to figure out all the different rpms you would have in a given range.
All crawl ratios are figured without the torque converter taken into account by any manufacturer I have ever seen.
I have seen calculations for the H1, but it also takes into account the wheel multipliers too.

[Wisha Haddan H3]

Thanks f5fstop ... I appreciate the info.

[PARAGON]

Originally Posted by f5fstop

Every equation I have ever seen for a crawl ratio has never taken into account the torque converter. Reason is it is next to impossible since the converter slips at a different rate at different engine rpms. Therefore, the calculation would be next to impossible. You would have to figure out all the different rpms you would have in a given range.
All crawl ratios are figured without the torque converter taken into account by any manufacturer I have ever seen.
I have seen calculations for the H1, but it also takes into account the wheel multipliers too.

as flywheel RPMs increase the torque converter is less and less efficient. The torque multiplication only occurs during a small RPM range on most small trucks due to many reasons. With electronics controlling lockup, along with the inefficiency of the converter itself, it's moot to consider it a factor for crawl ratio.

If one could effectively figure out the actual RPM range to hold the vehicle at and the electronics wasn't controlling the converter, you would burn the converter up and overheat the transmission.

[Michael1]

Crawl ratio with an automatic is just about meaningless anyway, with the torque converter disconnecting the driveline from the engine. Unless you like to launch off the top of rocks, and test your brake reflex skills, get a manual, with which the H3 has an exemplary crawl ratio.

Michael