rally7

Hey all

I need a gearset for my 13B. It's a race car with a massively bridgeported motor.

Anyone know what options are out there? I need strength.

Any dogbox options out there?

jgrewe

iTrader: (1)

Plenty of options for a dog box if you have $5 grand to spend. Elite,Saenz,PBS through Mazdacomp or maybe Jerico. You can get close ratios from a Miata 6speed box(about $500 salvage) and end up with a 1:1 5th gear. Even with a bridge you aren't going to have massive gear breaking torque and if you are road racing you don't have standing starts to try to split a tranny case. If you're drag racing go with an auto and have a custom converter built.

speedturn

iTrader: (1)

How much is your budget? You really do need very close ratios for road racing; around a 2:1 first gear and 1:1 fifth gear is ideal.
The Mazda factory has started reproducing the old factory road racing close ratio gear sets that will fit in the factory cases - will cost about $2500 plus lots of bearings and a donor transmission; would probably cost at least $3000 or more to get someone to assemble one for you.

wrankin

What year/model car is this and what rear end gear are you running?

RallyGTI

It is a 84 GS with a heavily bridgeported 13b and a 5.12 final drive. It is used for performance rally. The last close ratio gearset that the car had, self destructed after about three rallies.

speedturn

iTrader: (1)

How many thousand $ can you afford to get something super reliable?

RallyGTI

Right now we are looking at doing a T5 conversion. Does anyone have any experience with this kind of setup?

speedturn

iTrader: (1)

I run a PP road race motor and I have had experience trying a wide ratio trans on it - it is awful how your rpms fall below the powerband every time you shift gears. From the research I have done, the T-5 ratios are too wide to keep you in the powerband. Look at the 1st gear ratio - if it is numerically higher than 2.2 than the ratios are too wide to be useful with your bridgeport motor.

tims

T5 will be much stronger but it was designed to be used with a high torque V8 and the ratios are very wide. Can be reworked with some better ratios but this will not be cheap either. The other options have been mentioned but all are what I consider expensive even for racing. GURU Racing in Australia makes a gearset for the turbo II trans that is designed for road racing that would be strong enough, but it aint cheap either. Good luck

peejay

jake himes, izzat you?

what gearbox WERE you running? and i thought you were going to be going to some stockport meets the new Gp2 rules no power abortion? (or did you See the Light?)

Node

iTrader: (1)

OS Giken has some close ratio boxes, theyre still standard gear type w/ synchros. for t2 has full 5 gear set w/ new input/output shaft. for FD they have a 1-3 and a 5 gear set and i think its only a new input shaft.
I've seen them for about $1100USD for the 5gear sets. You still need to rebuild the rest of the tranny/synchros for another whatever that costs.....

j9fd3s

iTrader: (3)

another option, is the rx8 box, its basically the factory competition ratios with a granny gear 1st. and being built for a new car a brand new one is under $2500 if you're getting a deal

rally7

Yeah but I need to then buy the clutch flywheel starter, driveshaft and stuff don't I?

do you know the ratios on an rx8 box?

Yep, it's me Jake. Remner? That you?

billyboy

Seems pretty much you get what you pay for in close-ratio gearsets, the cheap ones over here you, wouldn't wish on your worst competitor. A lot of the circuit and rally regulars over here use these guys - you can see the use they are put to in the video.

http://www.ppgearbox.com.au/html/products.htm

But yep, not a cheap option even if it is in Oz dollars.

j9fd3s

iTrader: (3)

RX8 is

1st 3.76
2nd 2.269
3rd 1.645
4th 1.187
5th 1
6th .843

you do need the turbo flywheel, clutch, starter, and at least drive shaft yoke.

re10

Any more info about this?

peejay

Yeah it's me.

How are you breaking boxes? That'd probably be the first thing to consider, if you're breaking shafts and gears then you need a beefier trans, if you're just destroying synchros or dogs then you need to drive less like an animal.

I'm getting through about one season of rallycrossing (about 7-8 events, eight-ten "stage miles" per event) per transmission, and that's just rallycrossing not actual rallying. The synchros and such grind plenty of metal out, which circulates through the fluid and destroys the bearings, which scream like straight-cut gears and eventually cause huge vibrations like a U-joint is ready to fall out. I accept this as a condition of being mean with the shifter. Maybe a dogbox would help, or maybe I'd start breaking other parts instead, I'm not sure.

peejay

They only sell gears for the Turbo transmission, though. May not be a bad idea for strength, but it's more fabrication necessary. Personally I'm working on the "adapt a Chevy V8 T5 using an automatic's bellhousing" route, Chevy V8 T5's have a 2.95 First which isn't "great" but it's a hell of a lot better than 3.65 or 3.78 or worse 4.01! This would also include a new driveshaft, built with beefy American big-by-huge U-joints instead of the weenie crap, and probably cost less to do than to just have a new stock driveshaft made.

Oh and their gears are $9500AUD. ( !! ) That converts to something like $7k USD. For what that is worth, Quaife also sells a gearkit, 2.815/1.941/1.513/1.2/1.0/.790 (yeah six gears) for $9200USD.

Looking at those kind of prices, it only makes sense to adapt something more rally-proven like the Volvo or Ford boxes that certain people are always on about

rally7

I am thinking a max of 6kor so for something new. Still gathering a lot of info at this point.

The car is used for rally. It doesn't need to have perfect ratios but it sure wouldn't hurt.

I have an old factory box with a chewed up 2nd gear, not much damage to anything else. Does Mazdaspeed sell guts for these things?

I also would be willing to consider something used of good quality.

DriveFast7

iTrader: (1)

How about an external oil pump, with a nice Peterson 60 micron brass filter before it, going to a simple oil cooler and returning back to the box? At least it'll filter and cool better. Shockloading and other rallycross tranny craziness would still occur but wouldn't cost too much, I got my Peterson in-lin oil filter for about $100.00. Pump is about 150?

Try that, then get a trans rebuilt by a pro and see if it'll last more seasons?

I found out that the 1st gen tranny fill / drain plugs work perfect with Autometer trans temp gauge fittings. 1/2" NPT memory serving.

ajhehr

my understanding of the rx8 gearbox is that it is simply a miata gearbox and not that strong.

carbon man

I have done some work on an FD that CityPerformanceCentre fitted a Holliger 6 speed to and a (Harrob) ford 9" diff. VERY expensive but with 700hp unbreakable. You can get the Holliger with a siquential shift as well as H pattern.


http://www.cityperformancecentre.com/

http://www.harrop.com.au/

http://www.holinger.com.au

peejay

I already have that idea in-progress. Except instead of a $100 fancy inline oil filter, I'll use a discarded oil filter mount from a '96-up Chevy Blazer (the stock mounts corrode away, so they get replaced frequently... I have three in my "parts pile" and those are just the ones I *didn't* scrap for the aluminum) tapped to 3/8NPT, a standard normal oil filter, and for a pump just a generic fuel pump. Volvo used Facet fuel pumps for circulating differential oil in some of their road-racing cars. I have a spare OEM pump lying around, that should do the trick. The next transmission I have apart gets modified for a pickup and a drain, and a bashguard for the pump.

But first, I'm going to try Redline "Shockproof" gear oil, the heaviest-viscosity gunk they sell. It doesn't work well with synchronizers because of the extreme high-pressure lubrication ability, but I tend to just crash through the synchros *anyway* so what does it matter? If anything, it would help prevent floaties, which is my main concern in the first place.

I *am* a pro.

I'm also an aminal. I recently destroyed my current trans in about 100 miles of backraods driving. Constant 3-4-5-4-5-4-3-4-5 every few seconds, holding to a 5000rpm rev limit to hold noise down a bit... now the trans makes horrible screeching noises under load, and a distressing half-clunk half-gronk sound in any gear but 4th. Safe to say some bearings got pulverized

Like I said, it's dogbox time.

ajhehr

So at what point the HKS sequential come into play, anyone know any info on it?

peejay

Sequential = illegal.