Tell me about shifting a pro stock car (1 Viewer)

[DanTheFan]

I’m not an engineering type at all so a couple of curiosity questions about pro stock type shifters. In watching the in car camera shots of Jeg’s car for example, the shift light comes on and it takes some time to actually initiate the shifter movement. Is there a lead time built into the light? If so, is it customized for each driver vs pretty standard?
Also, the throws look pretty long. Is that a physical limitation (or rules)? Why can’t you make a short throw shifter?

 

[none]

The shift light comes on early because the engine is revving so fast that if you turned the light on at 10,500 you would be in the limiter before you react. So you set the light to come on at say 9,500 for low gear. Many (most) also change that as you go through the gears so for high gear when the engine is not revving nearly as fast the light might come on at 10,100.

And it is a fairly long throw because you need the leverage. Shifting a Pro Stock trans at high RPM is not a dainty task. You have to RAM it into the next gear so you need the long handle to help with that job. These things shift without use of the clutch and without any type of syncros in the conventional sense you have rapidly spinning sliders that you have to jam into a rapidly spinning (at a different RPM) gear and that takes some force. The long handle helps.

I did a video for NHRAs Facebook that explained gear ratios but I do show a gear and slider and how they engage that might help as well

Alan

https://www.facebook.com/video.php?v=387977815436751

 

[tenxal]

Alan, that was a great video and a concise explanation.

Here's another video that can help.

shifting a Liberty clutchless transmission - Search Videos

www.bing.com

 

[DanTheFan]

The shift light comes on early because the engine is revving so fast that if you turned the light on at 10,500 you would be in the limiter before you react. So you set the light to come on at say 9,500 for low gear. Many (most) also change that as you go through the gears so for high gear when the engine is not revving nearly as fast the light might come on at 10,100.

And it is a fairly long throw because you need the leverage. Shifting a Pro Stock trans at high RPM is not a dainty task. You have to RAM it into the next gear so you need the long handle to help with that job. These things shift without use of the clutch and without any type of syncros in the conventional sense you have rapidly spinning sliders that you have to jam into a rapidly spinning (at a different RPM) gear and that takes some force. The long handle helps.

I did a video for NHRAs Facebook that explained gear ratios but I do show a gear and slider and how they engage that might help as well

Alan

https://www.facebook.com/video.php?v=387977815436751

Alan, thx for the robust reply. Always enjoy your work at the track!

 

[Rajunz]

Here's a great video on the gearing in Pro Stock transmissions.