Dogged?

[SourceLee]

Anyone using a dogged transmission? if so what are your thoughts? According to the Interweb they’re either loads of fun or completely undesirable. Bucket list worthy? I located a transmission shop that can convert your conventional synchro tranny into a dog box. The cost is reasonable.

[rich grsc]

Almost undrivable on the street

[Gordon Levy]

Not a street box. Great fun at the track if you know how to drive one.

[Dave 53]

I've got an uninstalled dog box for my 818S in my shed. I was looking for a used LSD and ended up buying this tranny that has a LSD in it. I'm looking forward to installing it and giving it a go some time after I graduate the car in a few months. The idea fascinates me because of the very nature of it's difficult reputation. I want to try it because it's hard. I've viewed every YouTube video and read up a bit on the subject. I wouldn't suggest it's undrivable on the street - it takes practice. Maybe lots of practice, but once learned, all seem to have a smile.

Or... anyone want to buy an 818 dog box?

Stay tuned...

[CraigS]

I am w/ Rich. They have their place in a race only car but I can't imagine one on the street. Basically they get rid of synchros and replace them w/ the dogs. Not exactly the same of course, but think back if you've ever driven an old stick box w/ a non-synchro 1st gear. I bet you never shifted into 1st unless you were stopped. And even then, I bet you hit 2nd before you pushed it into 1st.

[rich grsc]

I am w/ Rich. They have their place in a race only car but I can't imagine one on the street. Basically they get rid of synchros and replace them w/ the dogs. Not exactly the same of course, but think back if you've ever driven an old stick box w/ a non-synchro 1st gear. I bet you never shifted into 1st unless you were stopped. And even then, I bet you hit 2nd before you pushed it into 1st.
yep
Think about driving an 18 wheel tractor trailer truck with a 15 speed gear box. :rolleyes: Thats what it'l be like, only a little worse as it's 'dog gears' not straight cut gears, that and it'l have a life of a few hundred to a thousand miles?

[Al_C]

a little off topic, but not that much... in a prior lifetime (1970-ish) I was a volunteer firefighter in a rural town. we had a 1939 International tanker - it was a converted oil truck - that carried a little over 1000 gallons. If I remember correctly, that truck had a non-synchro transmission (along with mechanical brakes). The ONLY way to shift that thing was to double-clutch. It was fun the first time you drove it, but a PITA any time after that. I think we finally retired that thing around 1973. Given that background, I'd pass on any dog-geared trans.

[J R Jones]

There were dog boxes before that name and race specific application came about. A Harley Davidson is a dog box, but most people use the clutch anyway. Still they are clunky. Our road racing Buells (HD V twin) had an ignition interrupting switch on the shift lever so the rider did not need the clutch after the transmission was in first.

"Clutch Dogs" are on the side of gears or spools between gears, to engage gears with shift forks. The dogs have draft on the load surfaces to lock them together. When abuse wears the draft away, the transmission will pop out of gear, actually pop out of dog, because the gear teeth are always engaged. You can use a clutch with a Dog Box.

Dave33 "I've got an uninstalled dog box for my 818S in my shed. "
Proper dog boxes have more robust components to take the shock loads, at least for a while. I suspect a Subaru box converted to dog shifting may not last long.
jim

[Dave 53]

A few notes for the above post based on my research and not actual driving experience.

One problem with a dog box is not that it's hard to get into 1st gear, but that it's too easy to get into first. At speed, it will slip into 1st just as easy as 3rd, then overrev and grenade the engine. When stopped, going from neutral to 1st or reverse might take a bit of clutch slipping to get the dogs to align and engage.

Once the proper shifting technique is learned, which is rev matching (which requires heel and toe skills or left foot braking), no double clutching is needed. No clutch is needed at all. The motto is, "shift it like you hate it!" The shifts need to be aggressive. If too timid you might miss your rev match window and using the clutch slows the process down. If missed, the clutch or double clutch might be needed to recover, find that rev match and get back in the game. Upshifts just require a split second lift of the throttle. Down shifts are the challenge.

Another popular misconception has to do with straight cut gears. Dogs vs. synchro and straight cut vs. helical cut gears are two separate topics. My tranny has dogs with helical cut gears.

To convert a OEM tranny to dog box is done by replacing the entire gear set, not by modifying the OEM gears in some way. The gears I have are made by PPG and are designed for the task.

I'm not trying to convert anyone (unless this experiment doesn't work out and you want to buy my awesome dog box tranny). It's most certainly more appropriate to put this tranny in an 818R and not my 818S. As I said, I was looking for a LSD and sort of fell into this thing. Seems that for a dog box to be fun, it must be mastered and I'm excited for the challenge of trying to master it. If I want to have an effortless drive and just need transportation, I'll take my boring BMW i3. When I take the 818 out, it's for the purpose of driving the 818 and I want that experience to be a full concentration extreme experience. I ride a fixie road bicycle - no freewheel. The peddles are always turning, and for awhile, it had no brakes (after learning to skid stop, I've since added a brake). I have a single speed mountain bike. They are harder to ride than a "normal" bike, I love it and people ask why I do it. Unable to articulate why, I just answer, "because I'm an idiot".

[J R Jones]

Dave 53, Do you have sequential shifting (inline) or an "H" pattern?
I speculate that you could sequence into too low a gear, but an "H" pattern is more discriminating. Dogging down to first will create huge loads and potential tire sliding (oversteer)
A sequential shifter on a Subaru transaxle is a complex and expensive bit of technology. Is the sequencing in the cockpit or on the transaxle?

My Buell riders did not double clutch for downshifts, they were speed sensitive and banged the lever. the interrupter cut the power. The clutch was still used when sliding the tire was likely.
Collateral damage from a dog box could be differential, axles and CV joints.
jim

[SourceLee]

It appears dogged transmissions are suited for specific applications. I'll pass and move on. Thanks for the feedback everyone.

[Dave 53]

Dave 53, Do you have sequential shifting (inline) or an "H" pattern?
I speculate that you could sequence into too low a gear, but an "H" pattern is more discriminating. Dogging down to first will create huge loads and potential tire sliding (oversteer)
A sequential shifter on a Subaru transaxle is a complex and expensive bit of technology. Is the sequencing in the cockpit or on the transaxle?

My Buell riders did not double clutch for downshifts, they were speed sensitive and banged the lever. the interrupter cut the power. The clutch was still used when sliding the tire was likely.
Collateral damage from a dog box could be differential, axles and CV joints.
jim

I have an H pattern. Sequentials are ridiculously stupid expensive.

A power interrupter switch would be used on upshifts. They were tried, but never took off in my go kart community. Increasing revs with a throttle blip is what is needed for a down shift.

Collateral damage will happen while learning to drive it by slamming and damaging the dogs without proper rev matching. The other potential for damage is over-reving the motor with an accidental downshift which a dog box will allow, but a syncro tranny won't. I haven't come across any stories or warnings of diff, axel or CV damage. Since rev matching is required to make a shift, it seems shock loading anything will actually be less with a dog box than with a synco tranny. I know I've upset my car with ugly clutch dropping non-rev matching down shifts.

No doubt, there's a reason dog boxes are unicorns in street cars. But, it's a fascinating concept and I encourage everyone to look up an article or YouTube video about them. I'm surprised by how many gear heads have misconceptions or know nothing about them.

Like SourceLee who started this thread, I was intrigued with the idea of a dog box. One unexpectedly crossed my path from an 818S builder that lives near me that gave up on his build and I bought it from him. I've read and watched all I can find about them (which is the info I'm sharing now). Let's give it a try I say! It could totally suck on the street and I hope it ends up in someone's 818R, or it could be a hoot! I'm determined to learn it and see for myself. Maybe I'll have it in for the April Huntington Beach show. Stay tuned...

[J R Jones]

Dave 53, I have not gotten to the duty cycle and failure stage yet, I just read about them here. In one instance that is extraordinary is Hobby Racer's ring gear fasteners backing out. Very odd.
My concern for collateral damage is the difference in progressive clutch engagement, with friction and damping springs VS metal to metal dog impact. My perception is a hammer blow with each shift.
You are right about the need for precise shifting. What I have seen in this FWD to Mid-engine adaptation is often compromised.
jim