Jump to content
The mkiv Supra Owners Club

PPG 6-Speed Gear Set WOW!!


fastisnice
 Share

Recommended Posts

Because they're noisy and generally a bitch to use when you're not on a charge. I've got a mate with a PPG dog box on a Scooby - it whines _all_ the time, apart from in 5th which isn't dog-toothed to allow quieter cruising (yeah right).

 

If he fluffs a shift, it can get stuck out of gear until he halts and re-engages first, but that's apparently not because of a bad build...

Link to comment
Share on other sites

The "dog" bit doesn't make the whine, the dogs are for gear engagement, they lock the gear to the shaft more strongly, and faster, than a synchro hub. The whine is because the gears are straight, raher than helically cut. Straight cut gear teeth whine, but have less power loss due to the almost total lack of end thrust, and their more efficient tooth profile. They are usually stronger, too.

Link to comment
Share on other sites

is the noise annoying for the street then i suppose?

I used to have a dog leg gbox M3 E30 and its amazing shifting from 2nd to 3rd, u never miss

 

Why is there so much misunderstanding and misinformation about dog boxes? This has NOTHING to do with the H pattern layout, and the fact that some boxes have first dog legged away from the normal H pattern. It's ALL about the deletion of synchromesh and the type of gear teeth form.

 

A straight cut tooth form can be extremely loud and sound like it's about to fail. A none synchro box on the road will also amaze most people with its crudeness.

Link to comment
Share on other sites

I run a straight cut box in one of my other machines and it is a seriously noisy bitch of a thing.

 

Reason I use one is that more ratios are available and also was having some side thrust load issues eating bearings and thrust washers.

 

Strength issue is a it of a red herring - it depends on the gear material - like for like material wise, a helical gear (the gear and teeth themselves) will be stronger as the load is spread over a larger tooth area - effectively more teeth are meshed. However the box as a package may well work out stronger as life is easier on thrust bearings in a straight cut box (as CW said).

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.