| Author |
Message |
BretM (Bretm)
| | Posted on Tuesday, October 30, 2001 - 5:53 pm: | |
Yeah it's that same basic idea. |
Tim N (Timn88)
| | Posted on Tuesday, October 30, 2001 - 5:30 pm: | |
Wouldnt having one on a road car be like driving a dump truck or something else without syncros? |
BretM (Bretm)
| | Posted on Tuesday, October 30, 2001 - 3:26 pm: | |
Yes there would be increased performance as shifts are a lot faster wihtout the need of the clutch. As far as enjoyment would be a lot less on the street as you'd have to bang all the gears into place (not a particularly nice feeling) and most don't shift very well at all until tached up to like 7000rpms. It's a real rough and tough way to shift, nothing like the smoothness of a normal road car trans. |
Steven J. Solomon (Solly)
| | Posted on Tuesday, October 30, 2001 - 1:40 pm: | |
Thanks, I think I understand now. Any purpose in installing them on a road car? Would there be a real difference in performance? |
BretM (Bretm)
| | Posted on Monday, October 29, 2001 - 6:13 pm: | |
Yeah that one that was in the lady's garage for a long time and somewhat of that "lost car" thing until the 80s. That was a good article too. |
Tim N (Timn88)
| | Posted on Monday, October 29, 2001 - 6:00 pm: | |
I read that article, it was really good. I like it when car mags have an article about oler cars. Did anyone read the one in Car & driver about the first shelby cobra daytona coupe? |
Martin (Miami348ts)
| | Posted on Monday, October 29, 2001 - 2:32 pm: | |
that sounds all spanish to me.... |
BretM (Bretm)
| | Posted on Sunday, October 28, 2001 - 11:56 pm: | |
They had a great article on them in this months Road and Track, about the Chaparall race cars that used them coupled with a torque converter. Worth checking out. |
'75 308 GT4 (Peter)
| | Posted on Sunday, October 28, 2001 - 10:39 pm: | |
The gears in the transmission are always in contact (meshed) with each other, its the engagement mechanism which connects the gear to the shaft. In racing applications they use a dog type of engagement, usually six large, square-profile teeth on the ring, with a matching set on the gear. Light (sissy) pressure on the stick shift just gives you a buzzing, grinding sound, because the engagement rings are just riding on the flat surfaces of the dog teeth. "Crashing" the stick at the right RPM, will put the required force to jump that flat surface and drop into place.
Synchronised boxes use multiple engagement rings that have a tapered, cone profile and the teeth are many and are pointed. The cones allow some slip until the teeth are aligned and shaft speeds and engine speeds are matched and will engage.
Helical-cut gears are quieter, but have sliding contact with each other, straight-cut gears are louder, but have rolling contact with each other (more efficiant and stronger). |
Tim N (Timn88)
| | Posted on Sunday, October 28, 2001 - 4:12 pm: | |
Straight cut gears also use less power to friction or something like that, i know they are more efficicent, but i think i heard somewhere that they cant transmit as much power as the same tranny with helical gears because thee is less surface contact between the two gears (not sure how to word that)But they are used in race cars bc they are lighter and dont rob as much hp |
Paul Prideaux (Paul355c)
| | Posted on Sunday, October 28, 2001 - 3:23 pm: | |
I can answer the question 'what are they' but not why you would want them.
Straight cut gears (or spur gears) have the teeth at 90 degrees to the plane of the gear, opposed to helical gears that have the teeth at some angle (like 60 degrees) to the plane of the gear.
Helical gears are used in most automotive applications because they are quieter. Spur gears make that gear noise you think of in a school bus or a very old car. Many cars have spur gears for the reverse gear only. Hence that 'gear' sound.
I don't know if some people are installing straight-cut forward gears in cars for some reason.
Let me know if this was not clear. |
William H (Countachxx)
| | Posted on Sunday, October 28, 2001 - 3:06 pm: | |
straight cut gears r usually found in race transmissions, typically called "Crash boxes" cus u just crash the stick between gears. They have no synchros to save weight. These would b aftermarket on new cars although some 50s & 60s cars may have had them from the factory.
I would guess they may b illegal in showroom stock or classes that try to limit costs |
Steven J. Solomon (Solly)
| | Posted on Sunday, October 28, 2001 - 2:33 pm: | |
Can someone tell me what straight-cut gears are? Are they factory items or aftermarket?
Also, I heard they were illegal for some forms of racing-why? |