Fantastic Dogbox for RX7
 

I have recently started to run a GURU Dogbox gearset (manufactured in Australia) that is fantastic. I use it in my racer (Gen 1) but it also fits into all other housings.

It fits directly into the standard Mazda housing and is made to the same manufacturing specifications as a V8 Supercars (Australian - Bathurst etc).

Has anyone else tried a dogbox or are interested in more technical information? FYI also applicable for performance road or drag cars.

How much, and what gear ratio's, Torque capacity, thickness of input shaft, Diameter of front input shaft bearing, Straight cut?

I want a 4th gear 1:1 instead of a 5th gear 1:1, tall 1st around 2.7:1, parts and avilability, is a big deal also, replaceable dogs?

I had the following gear ratios installed, I know they can do others, you just need to discuss.

Gear Ratios:
1 - 2.387
2 - 1.705
3 - 1.339
4 - 1.144
5 - 1.00

Torque Capacity - In excess of 650hp

Not sure on the thickness of the input shaft or shaft bearing, I will find out and let you know. What I do know is they will fit directly into Gen 1 - Gen 3 engines so therefore I know they use the standard tail & input shaft splines parameters.

Cut - latest advanced dog geometry & 5 dog tooth profiles

All Parts are avail and can be shipped anywhere within a couple of days,
gears slide on cluster shaft for easy assembly & disassembly, changeable dog rings on 4th & 5th gears.

Price approx $4990 USD

I can tell you I have looked at Quaife, PBS, Sanz, Mazdaspeed and the quality, service and workmanship is the best I have ever seen! No wonder the V8 Super (Australia) teams use this technology. The gears are made from EN36Var Aerospace Vacuum arc remolt case hardened. They have recently been at show is the UK where they went off in abig way.

Have a look at gurumotorsports.com, some more information can be read at that site.

One unit won't do that. N/A and Turbo manual trannies had different input spline count/diameters as well as different trans lengths and output shaft spline count/diameters. I assume they use the Turbo standard.

HI,

You are correct, one unit will not do that, when you order it you tell them which fitment you are after and they supply a different legth shaft with the correct fitment etc as well as the bearing etc. In mine I use the Turbo standard one.

wuts a dogbox? like a seq. shift or what?

Do you still drive your car on the street? GF5R is dope and you can use the H pattern shifter to keep streetability ;) Then mid 9s will be a breeze for ya;)

normally transmissions have synchronizers - there are splines on a gear, and splines on a slider that is attached to the shaft the gear spins on. There is also a small clutch between the two (the actual synchro). When you shift you move the slider to engage the splines, and the synchro rubs between the two until they're moving at the same speed and then the slider mates with the splines on the gear, and away you go. Nice, smooth, but can get balky if you try to shift too fast or too hard.

Dog trannies don't use that setup. Instead of splines, they have 9 or 10 big fat lugs, or dogs, on the gear and on the slider. No synchro. You just move the slider and CLACK it's in gear. The faster you shift, in fact, the less wear on the transmission. Downside is you HAVE to rev-match a downshift or it'll just grind, because they're non-synchronized. That's no big deal, really, the only people who say they're not streetable are the people who don't want to learn how to drive them. Before the 40's and 50's it was rare for ANY transmission to have synchros - I think modern tractor-trailers still have non-synchro transmissions!

Hi, Yep it is both for the race and road use.

The pattern is 1st (back), 2nd Upwhere 1st is in a standard box, 3rd, straight back etc

The short shifter on the set-up is great, exceptionally short!

With a dog box, you still have a clutch tho, right? And you can shift without the clutch also? I know next to nothing about dogbox's except for what I read here.

35millisecond shift times we have measured these transmissions down to, you dont even have time to look at the clutch ! If anyone needs some tech information on these trans kits i have most of it on hand .

Rohan, send me those specs please.

marco@magnusmotorsports.com

twister thanks for the quick responses.

Have a look at this , internals of my dog transmission , no wonder we are kickin ass !!

I would be interested in any other info you have as well.

turborx7@lvcm.com

Thank-you

Have you checked out the GURU web site, it has a fair bit of information (apparently still in early development stages, the web site). They are about to put a heap of photos on of the transmissions and torsen diff within the next couple of days.

The technology and engineering in the transmissions design leaves any competition in this area miles behind.

http://www.gurumotorsports.com

whats the corect way of using it? like when do u shift up and when do u shift down?

It is just like a 'syncro' box, just with straight cut gears so you can change gears without using the clutch! You still change gears the same i.e. once you have reached your maximum rev range in each gear. The correct way to use it is to be decisive with it, not pussy around with the gear changes. The gear changes are much much quicker and smoother, it prevents the revs from dropping off.

They are much stronger than any standard and most pro boxes. Just what you need for circuit and street drag sort of cars!

So what is it like driving this tranny around on the street? I mean what if you are just out for a spin and arent planning on banging through the gears? I just wonder how smooth it would be if you just out for a spin. It just seem like gear changes would be abrupt and break the tires loose and snap your neck back even when your not at wide open throttle. Could you describe the "experience" for me. I really need to take a ride in a car that has a dogmission to see for myself. They seem like an awesome setup just not practical at all.

Twister;

So the Quiafe 6 speeds dog engagement gear sets for the RX-7 is used in the same way as you described right so basically it works as any standard manual trans but with no synchros so I can shift as fast as I want and if shifting with ease meaning going from gears to gears without that fast shifting will it messed up the gears cause from what you described you have to shift fast.

Hi, for normal road use the gearshifting is fine but the gearbox is fairly noisy due to the fact they are straight cut gears, as per all 'pro' boxes. The gear changes are very smooth and do not 'snap your head back' and do not break the tyres out, otherwise racers would not be using them. The whole gear change is actually much smoother than a normal box.

And look, they are really pratical for the street if you except the noiser gears. Re the experience, I will see if I can get some in car video with noise so you can understand what I mean. Or see if you can find someone with something similar.

re the Quaife, yes same idea just not to the same quality or strength (when you actually look at the quality of the gearsets, Guru is streets ahead!). You use it just like a 'standard' box, you do not need to shift it fast but that is the basic idea why they were made, ie.to reduce shift times for racers/drag etc. You have to be precise that is all.

You hear about all these drag guys breaking boxes etc, with these it is a thing of the past!

Man that sound sweet as hell! So is so loud you cant listen to some music? I know several exhaust systems like that :D

You can still listen to music, but just have to switch it up a bit. :p:

When you hear it coming down the street it sounds unbelievable, like a race car is coming up. You can really tell the thing has some serious performance in it.

Nice... hmm 5000 + shipping from down under. That has GOT to put a dent in someones platinum card.

to hear a good impression of straight cut gears, just drive in reverse. whirrrrrrrrr. Or play some gran turismo 3 and put a racing tranny in the car. whirrrrrrrrr

The price is not cheap, but you pay for what you get! i.e. Excellent quality stuff.

I have been thinking about this ? on price and had a search on the net, when I compare it with the price from competitors $5k is a fair bit less than the competition. I also had a think about other money I had spent on my car, and can honestly say the 5k for the transmission was the best 5k I have ever spent on performance enhancing modifications.

Re shipping, I would say it would not be that much these days and I have heard they are going to be selling them via a distributor in the US maybe. When I have shipped stuff from OZ in the past it can cost as low as $7 per kilo and be delivered within 72 hrs, therefore a gearset is about 15kg, not much! :p:

hey so i can change the gears at any revs....

u said thts its like the V8's series box and i saw they use the cluch when down shifting.... :confused: whts with tht....

ps do u distribute to nz?

Well you can change at any revs but it is not magic, i.e. you have to be going fast enough to change up otherwise the engine will just drop off the revs etc.

With the V8's (and with this) you can use the clutch to change down, in someways it is easier to match the revs by using the clutch and heal-toe etc.

And yes of course GURU Motorsports will sell into NZ, that is not far from Melbourne where they are based! Also with the V8's rememebr thay want nothing to break for the entire day (1000k's at Bathurst is prettty tough) so they try and be real careful with the entire car so it depends who is driving it how they drive. Some drivers are easy on cars and others not!

ive actually heard something about reverse gears are dog gears and no synchros. is this true? and that might be why it sounds like that.

Well yeah there are no syncros on your reverse gear, because you don't engage reverse when you're moving :D I'm pretty sure it's just a plain spline engagement though

i heard tht the sreies V actually has a synchro for som od reason... but i thnk im wrong... maybe it was the firs gear

hey twisty then let me rephrase the question what is the optimal rpm for shifing up and shhifting down....

any time now

menace... depends on the car :) my '85 stockport 12A best shifting is upshift at 6k because it only makes noise, not power, above that, likewise downshift when revs drop below 4k... my '80 street port = upshift at 7600-7800 (8k with open headers) and downshift below 5500 or so depending on gear (open exhaust is dragstrip only = no downshifting) coming out of a tight corner it was better to leave it in 3rd and bog a little instead of trying to pull away in 2nd - rips up the tires too easily in 2nd and it sucks to have to upshift right away out of a turn.

Reverse gear (at least on the 12A trannies I've had apart) is a straightcut gear with no synchro. They're not dog-ring style, though, it's just like a synchro type with the splines except there's no synchro in between the slider and the gear. That's why it grinds if you try to shfit into reverse from a stop unless you momentarily shift into a forward gear to get the tranny internals to stop spinning. (Incidentally a lot of trannys have a crashbox setup for reverse... instead of sliding a slider over teeth on the side of the gear, it actually physically moves the gear in and out of contact with the reverse idler gear. Pretty neat!)

I would like more info on this gear box too, if you could email me at ZM97@aol.com

thanks KIMO

Have you looked at the site www.gurumotorsports.com ?

Plenty of good information can be found at this site.

Guru Motorsports

so when you are sitting in the driver seat do you see one shifter or do you see 6 of them? also is it sort of like shifter the stock tranny without using the clutch?

Twister, Do you know about Select Mazda gear boxes? They offer a similar setup for $4200 AU which works out to $2200 US. They claim the boxes can take 500+ HP.
Here is the link:
http://www.selectmaz.com.au/main_frame.htm

Hi,

Yes I do! Lets say they also run Guru products within their race car!

I am unware of any racers in Australia who use that product, I do not think any have been sold for a long time to 'racers', it is basically an upgraded 'standard' Turbo box not a complete racing gearset! They used to be state of the art, but have been out of it for a little while.

? to ask include the following
Warranty, parts, relability, hp strength! , availability, quality, strength, ratios!

Have a look at the shifter etc, the Guru products are for FC & FD the box they sell is appropriate for FC only.

The quality (as can be seen by the photos) of the Guru products is better than almost (if not all) pro boxes. I do not want to say to many things about some of Guru's competition but you pay for what you get! We really are talking chalk and cheese. What is important is what is inside i.e. the gearset, or do you just want a 'cheap' box!
Drag, race or street GURU is the way to go.

Guru Motorsports

ha, so is that $5000USD? And are there any cheaper doggears? I mean, not to say cheap isn't pretty bad, but $5k is a hell of a lot of money.

Shit the HKS dogmission is like 6 g's....

Yes 5k USD. Cheaper yes, more expensive yes much!!, any better , nup! I have tried several and will continue to rave about this one, that is why the V8 Supercars here in Australia use exactly the same from the same guy!

Hi, just the one shifter! I do not think I could handle six! :D

Shifting between gears in a straight cut gearbox is not like shifting in a normal box. The shift is so smooth & faster!!!!!! So much it is unbelievable so you do not loose engine revs and if you want to win you will never go back again after trying one.

So what are the cheaper ones, just curious, and this is pretty cheap considering the prices of racing trannies.

FWIW it's not the straight cut gears that change the shiftability - the gears do not slide in and out of mesh, they stay in mesh at all times when you have a synchro or dogbox setup.

However straightcut gears are a lot stronger than angle-cut gears and they don't put any nasty side loads on the bearings! (Plus they sound sweet too!)

- PJ (My car has bad countershaft bearings, it only SOUNDS like straight cut gears :) )

Twister,
Is $5k the price for the complete gearset or is it for a whole gearbox?

Hi, 5K is for the entire gearset and short shifter etc (have a look at their website, a great photo of the actual kit is shown on it). They distribute it this way to keep your tranport costs down. The only thing not included is the casing (ie. the outside case). They will supply a case if someone really wants it but the cost to ship around the world is fairly high.

www.gurumotorsports.com

Sorry menace not to reply sooner.

As peejay said it depends upon your car, so it not just one answer. In my racecar I change gears at maximum torque about 9'200 revs but of course you can go higher when you need tooooo! But of course you can also change sooner if you have to, if you look at the guru site you will see the thickness of the gears and the quality of the dogs etc, this is why this box is so much stronger and better than any other for the RX7. the reason these guys built them was they could not get any other proboxes to last for a decent amount of time. It gets expensive to keep on replacing tranny's! So this is why the box is designed for such high performance and strength.

Things are looking good for me to get the dogbox....getting everything else cleared up on my car and it'll be ready to drop in and go.

This might sound stupid.....but how does this tranny react on the dyno? Will it shift differently because of no load or is that a stupid question?

Twister....you've been really helpful with all our questions....thank-you. I'm glad that you posted this....because now this is one less area to have to always question whether it will last or not.

the website seems to b down... WTF?