Which transaxles can be dog boxed?

[Ben]

I'm researching transaxles, and am wondering which, if not all, are able to be dog boxed? (straight cut gears) I'm pretty sure the ZFQ is straight cut stock, but is it sequential as well? I'm debating if I want sequential or not, but I do know I want straight cut gears. I tried searching the forum, but didn't really come up with anything during my search, so if this subject has been beaten to death already, I apologize, I'm new.

I'm open to all opinions and experiences of dog boxing and sequential shifting. And thank you all in advance for your input.

 

[Rick Muck- Mark IV]

Hewland FG/LG series

 

[Ian Anderson]

Try Elite Racing Transmissions nice products but their website is currently down

Ian

 

[Seymour Snerd]

I'm researching transaxles, and am wondering which, if not all, are able to be dog boxed? (straight cut gears) I'm pretty sure the ZFQ is straight cut stock, but is it sequential as well? I'm debating if I want sequential or not, but I do know I want straight cut gears. I tried searching the forum, but didn't really come up with anything during my search, so if this subject has been beaten to death already, I apologize, I'm new.

I'm open to all opinions and experiences of dog boxing and sequential shifting. And thank you all in advance for your input.

I'm pretty sure that as originally envisioned the ZFQ was to have a non-synchronized and/or straight cut gear option. I'm pretty sure it's NOT straight cut stock. See http://www.gt40s.com/forum/vendor-m...ts/20751-zfq-new-proposed-gt40-transaxle.html. Whether that happened or not I don't know but the direct way to find out would be to ask Quaife.

Also, I seem to recall that one or more of the new Griffin transaxles was to have that option but again best to go to the source: Complete automotive transmission services, transmission repair and regular maintenance servicing

You might also check Mendeola. http://www.mendeolaint.com/

I'm a little confused by the way you're using the terminology; I know:

• straight-cut or spur vs helical gears
• synchronized vs non-synchronized
• sequential vs non-sequential: having only an upshift vs downshift control vs being able to select gears individually.

Where does the term "dog boxed" come from and what does it mean exactly?

BTW over at http://forums.nasioc.com/forums/showthread.php?t=665334 it says "A dog box is the term for a transmission utilizing a dog engagement. A dog box can have either helical or spur gears or both."

 

[Scott Calabro]

Not sequential but straight cut.

Click the link below;

Tornado Sports Cars Letters Page

 

[Ben]

@Alan

I had read a magazine article that said Straight Cut Gears was also known as "Dog Boxing." It was a tuner magazine I had picked up for an 18 hour road trip, might still be laying around if you're interested. As far as sequential, I was using that correctly. Though I haven't driven a sequential before, I was looking for input from the community. Would it be decent for everyday driving, or would it be too much of a nuisance? But then again, you can get used to anything, right?

I'll delve into all of the links you've all supplied in short time. Again, thanks everyone for your input.

 

[EGLITOM]

There is a good explanation on Albins gears about what is a dog shifted gearbox, what are the advantages and the disadvantages.

Albins off Road Gears :: Synchromesh and Dog Engagement Gearsets... What are the differences? :: Transaxle :: Transfer Gears :: Gear Design :: Performance Gears :: Gearsets :: Dog Gears :: Performance Transaxle :: Sequential Transaxle

Ben i would recommand to read through that and than think what purpose your car should mainly serve. If you want to race it full competition with a high powered engine you could go to a dogshifted box for quicker shifting action. But as a dogshifted gearbox is not nesseccarely a sequential gearbox shift time improvement with a H Gate dogshifted box will be marginal if any.

Albins is offering a dog shift conversion for the 930 type Porsche 4 speed box

Holinger is selling a sequential dog shift conversion Kit for the G96 GT3 6 speed gearbox.

http://www.holinger.com.au/pdfs/pcs.pdf

OF course Hewland LG 500/600 but this are realy old style gearboxes made for the Sports and Can Am cars of that time. Very expensive and realy just build for strength. Due to that realy heavy gears with a lot of inertia mass and therefore not quick to shift at all.

If you take a modern Porsche box like a G96/50 (6 speed turbo box from the 996) this will give you perfect ratios for a standard RPM V8 ( RPM till 6500 max) modern syncromesh system, and therefore good performance for money.

TOM

 

[Seymour Snerd]

@Alan

I had read a magazine article that said Straight Cut Gears was also known as "Dog Boxing." It was a tuner magazine I had picked up for an 18 hour road trip, might still be laying around if you're interested. As far as sequential, I was using that correctly. Though I haven't driven a sequential before, I was looking for input from the community. Would it be decent for everyday driving, or would it be too much of a nuisance? But then again, you can get used to anything, right?

I'll delve into all of the links you've all supplied in short time. Again, thanks everyone for your input.

The older term for an unsynchronized transmission is "crash box". Probably where the magazine got confused is that crash boxes and straight cut gears tend to go together, but not always.

I have no experience with sequential shifters on street cars. On motorcycles, of course, that's all there is, and they're wonderful.

The common wisdom is that crash boxes are usable but not appropriate for street driving. Older truck drivers might disagree. I've driven a crashbox only on the track, where it was great for pseudo-clutchless shifting (preload the lever and stab the clutch for what feels like an instantaneous shift like you would do without the clutch at all on a dirtbike.) But those cars either had rotoflex couplings or were otherwise designed to take that abuse. Whereas your CV-jointed GT40 might not be too happy about it. So then you would have to double-clutch to do your own synchronizing. Which is OK, it's just becoming a bit of an arcane art, and your left leg would get tired in traffic.....and your passengers would wonder what the hell's going on if you didn't quite do it right.....

 

[Seymour Snerd]

Also, I seem to recall that one or more of the new Griffin transaxles was to have that option but again best to go to the source: Complete automotive transmission services, transmission repair and regular maintenance servicing

Oh, Bad Mistake! The URL for Griffin above is wrong. The correct one is

https://griffingearboxes.com/Home.php

Sorry, DeLynn; Sorry everybody

 

[Troy]

Try Elite Racing Transmissions nice products but their website is currently down

Ian

I have the Elite Racing TXL300 sequential 6speed in my GT40. The TXL250 with the wider gear option would also work. Mine has straight cut gears / dog engagement, but they also have helical cut gears and synchromesh options.

 

[EGLITOM]

Troy

Can you tell more about your experience with the TXL 300 ?

TOM

 

[Ben]

Let's change direction a bit, shall we?

What about paddle shifting? What would the best set up be for that, and how hard would it be to convert? Might sound like I should lean away from straight cut gears since this would primarily see road time on the highway, not on the track. But don't get me wrong, I have a friend with a Corvette that I'll show up every chance I get.

 

[Seymour Snerd]

Let's change direction a bit, shall we?

What about paddle shifting? What would the best set up be for that, and how hard would it be to convert? Might sound like I should lean away from straight cut gears since this would primarily see road time on the highway, not on the track. But don't get me wrong, I have a friend with a Corvette that I'll show up every chance I get.

(Straight cut gears are really noisy; I've only experienced them in a race car so I didn't care. But the rationale for them is to tolerate large amounts of power input while wasting little of it, so unless you're going to do something outrageous in terms of power plant I don't see the point).

So, changing direction....

For the mainstream GT40 gearboxes the only way to do that I know of is: Paddle Shifters, Sequential and Electronic - ASaP

I know they have put it on a ZF and on some Porsche units. I hear a lot of debate about how well the transaxle tolerates it, but have no opinion or knowledge of my own. I did see it running at a car show once and it certainly looked cool. They even have a "preselector" function where you choose the next gear first and the shift occurs when you stab the clutch.

I really wish somebody would do this with a GT40 and ZF and tell us how it worked out. :laugh:

 

[EGLITOM]

(Straight cut gears are really noisy; I've only experienced them in a race car so I didn't care. But the rationale for them is to tolerate large amounts of power input while wasting little of it, so unless you're going to do something outrageous in terms of power plant I don't see the point).

Not quite sure if a straight cut gear of the same dimension can take more load than a helical cut one. I always thought the main purpose of straight cut gears is to not put any axial load to the bearings in the gearboxcasing and thus enabling the box to take more power. In combination with a conversion from syncromesh to pure dog engagement of course the gears can be designed wider and thus taking more power.

This Mastershifter solution is a smart idea, but wow to install this and getting it running reliable will take some effort ( besides finding the space in GT40 for the shifter motor case. Most annoying i find there question " if it is in shelbys car , don´t you want it in yours?" Hmmmmm?

I´m with you we should be open to such solutions. Anyone out there, want to try for us ?

TOM

 

[Ben]

Not quite sure if a straight cut gear of the same dimension can take more load than a helical cut one. I always thought the main purpose of straight cut gears is to not put any axial load to the bearings in the gearboxcasing and thus enabling the box to take more power. In combination with a conversion from syncromesh to pure dog engagement of course the gears can be designed wider and thus taking more power.

This Mastershifter solution is a smart idea, but wow to install this and getting it running reliable will take some effort ( besides finding the space in GT40 for the shifter motor case. Most annoying i find there question " if it is in shelbys car , don´t you want it in yours?" Hmmmmm?

I´m with you we should be open to such solutions. Anyone out there, want to try for us ?

TOM

Only big benefit I know as far as helical cut gears is that they contact at one point and then spread the load over the tooth as it rotates creating less noise, which would also attribute to the fact they can't stand as much torque as straight cut gears.

If I had the money and expertise, I would give it a heck of a go but.... I don't know jack about transmissions, hence why I started this thread.

 

[EGLITOM]

Ben

Fully understand your questions. Allow me one comment. In my experience, one of the things which makes driving a GT40 so special, is the seating position in combination with the manual shifting action.

This is the real thing. A mans clutch ( if you have the correct combination of master/slave/pressureplate it is comparable to a stock Porsche clutch, not GT3 or RS clutch) and a crisp shift feeling in combination with the push and sound of the V8. That´s what it is about. Would not want to miss one of this components.

The cable shifter supplied with the RCR Kit works fine and can be adapted to your shifting action desires by adapting the lever lenghts.

What power level enginewise you are looking for? Based on that we could give you recos for your gearbox.
TOM

 

[Ben]

Engine I'm currently looking at is the 5.0 coyote supercharged. I'm hearing it will have some vertical clearance issues with the back glass, but I don't care, can mold a custom one if need be. That's just what I'm currently looking at, I may change my mind by the time I actually get my car let alone the stage of installing a power plant.

 

[Seymour Snerd]

... but wow to install this and getting it running reliable will take some effort ( besides finding the space in GT40 for the shifter motor case.

I don't know how big the ZF version is, nor where they put it exactly but I don't recall the working model at the show taking up much space,and I think it arrives ready to bolt on at the transaxle end, so you're in for some wiring but that's about it other than fussing with the steering wheel, etc. In the case of my SPF I don't think it would be hard to fit it between the long subframe bars.

As for the reliability I don't believe the end user or installer has much influence over that (well, I can screw up the installation of anything...). The sequencing and control of the shifting is all within their electronics, AFAIK and is specific to each gearbox.

 

[Stephane Goria]

Hello,

Spur vs helical :

Very often, I read that the common belief is that spur gears are stronger than helical gears. In my opinion, this is wrong. Helical gears are superior to spur gears. Beside the quietness, the load carrying capacity is far superior with an helical assembly as the mating surface is obviously wider with an helical and also because the load distribution is progressive.

Dog engagement & UN1:

The Renault UN1 is widely used for conversion to dog engagement. he benefits are the followings :

- you have for a reasonable price a very strong housing with all the links and forks
- you have a bullet proof output shaft : basically with a breaking point of 1560 ft-lb and so, a calculated max torsion capacity of 905 ft-lb, wich is not too bad...so even taking a safety factor of 0.50 it gives you a 452 ft-lb load capacity.

- You get rid of the weak primeshaft and get it replaced with a stronger one.

- You have the benefits of a 2 parts Inputs : Input shaft & intermediate shaft, far better than a straight single shaft.

- You have access to 4 final drive : 3.44,3.89,4.11,5.86

- you can have whatever custom made gear ratio configuration allowable in a 75 mm center to center.

- a lot of manufacturers are making adaptors plates , this allowing the UN1 to be mated to whatever engine, others make even special bellhousing, sometimes better as it allows to fit wider clutch assemblies.

Discrepancies :

You have to add a lubrification system to cool oil and the Splash lubrication system is obviously less effective than a pressurized system or an every mesh being oil sprayed.

The 75 mm center to center is a bit too small and will not allow very low gears to be cutted.

This being said, if you intend to cruise with your car and just not go on a track, it could be better to think about a synchronized system as driving a dog enagemenet gearbox in traffic is a real nightmare.

Greetings

Stephane

 

[Rick S.]

I was under the impression that a "dog" box with straight cut gears could take more abuse (clutchless-shifting) than the same box with helical cut gears? Maybe I'm wrong...