Tranny Talk

[Umai Kakudo]

This kind:


Not this kind:



After years of faithful service my SR20 transmission blew up it's 2nd gear after one clutch kick too many. It sucked to have to replace the transmission at the track and I don't want to do that again.

I am in possession of a FS5R30A (from a '88 Z31 Turbo - Same as the Z32 and RB 25+ transmissions)

Infos:

http://www.az-zbum.com/information.transmission.shtml

Plan on getting a Xcessive Motorsports adapter kit to install.

My primary use is street driven drifting. Need something that can handle some shock loads from a stock SR with 12psi T28.

The Z31/Z32/RB trans is nice and strong but it also is larger in dimensions making installation and removal difficult especially spaced back with an adapter.

What does everyone use and are there any affordable swap options besides the FS5R30A that have smaller sized bell housings?

Any preparation tricks from the road race world? Any race prep shops that have bolt in options for the rear wheel drive SR worth looking at?

[djsilver]

If you've got years of clutch-kicks out of this one it's not really that bad! There's not much out there that's as light as the stock trans and still as strong. If you'd consider sticking with the stock unit, you might try sending the gearset out for shot-peening for greater strength. Shot-peening is a widely used technique in strengthening industrial components of all kinds. There are a number of race-type service companies that perform shot-peening for automotive components. There are also some extra-fancy variations out there like WPC treatment (http://www.wpctreatment.com/) or "Temper-Shot" (http://www.ppi-ats.com/Tempershot.pdf) If that's not fancy enough, just google "laser shock peening" for some really interesting technology!

[Matt93SE]

Jerico 4 spd, baby. they're good enough for NASCAR and most of the road race world.

oh wait.. you said streetable.
GM or Ford T5 with adapter plate?
G-Force sells synchro+helical T5s with a couple different gear ratios you could use, or you could go to a dog box and do custom gear ratios. but again that's not terribly streetable. you could street drive it, but it wouldn't be terribly fun.

Richmond also makes a 5 spd with a T5 bolt pattern. DSG was using a G Force T5 dog box in their car and he still has the clutch, adapter plate, driveshaft, and eveyrthing you'd need. just find you a T5 with matching input/output shaft splines and go to town.

probably a bit more hardcore than you want.

Thing is, with a properly set up tranny and clutch assembly, you shouldn't have to worry about it being a PITA to drop a tranny out of the car. I've been road racing my tranny for 5+ years and haven't broken anything yet. replaced one clutch disc and that's it.

I'd recommend a Z32 or RB tranny myself. again.. put a good clutch and flywheel in it and you shouldn't have to take it out but once every few years. so what if it's a PITA if you do it every 3 years? what's another hour of work at that point?

As for what I do with it?
1. don't kick the clutch. ( I know.. hard NOT to do when you're drifting. but the shock loads are what kill trannies, and that's inherently what drifters do..)
2. don't jam the thing into gear.
3. 1/2 and 1/2 mix of Redline lightweight shockproof and MT-90 fluid. you could run full shockproof too, but be prepared for your fluid to look like oatmeal. but it works.

[Def]

Matt, I thought KA/SR trans were super unreliable on track according to you?

[Matt93SE]

They are when you go above 200whp and put slicks on the car.
I have at least 50hp to go and I don't run slicks.

[Umai Kakudo]

I've been running Red Line HD Shock Proof straight for years ever since I had a 2nd gear syncro go out and get so bad it would barely shift but once I put the Shock Proof in it shifted like butter again.

Only down side is you have to shift slow and easy until the fluid warms up.

Anyway, I lost out on 90% of a track day due to the transmission failure and would rather beef up the trans and not have to worry about it in the future.

So far I've only broken 1 gear and 1 stock S13 axle while running a maximum of 255 UTQG 200 tires drifting. I learned a long time ago not to shift like a 16 year old who just saw the Fast and the Furious for the first time.

Normally, I just need a light love tap clutch kick on initiation but I was on a go kart track and having boost issues (wastegate actuator rod fell off the flapper lever!) so I ended up kicking the clutch a lot more than normal to get it in the power band.

If I can find a 5 speed option that is just as strong as the FS5R30A, smaller dimensionally for easier service, with the same or better gear ratios that would be sweet.

I'm not sure about the T5 option as it seems some have good results and others don't.

I was curious if anyone has seen any Tremec TKO conversions for Nissan?

http://www.hurst-drivelines.com/index.php?option=com_content&view=article&id=233

Seems like a beefed up, modern version of the T5 with a non integrated bellhousing and torque capacities up to 600 ft/lbs.

I see a lot of people talking about this conversion but haven't found any off the shelf bellhousings for them. The AU folks have a lot of companies that do bellhousing kits for Japanese cars but I haven't found one for the SR20 yet.

Shouldn't be too much of an issues to take a SR20 bellhousing, deck the back end of it, and weld on a plate to bolt up to the TKO. Bonus is that you now have a T10 compatible bellhosuing for when you want to get freaky and go for a 4 speed dog box.

Example of a SR20 Bellhousing modded to fit to a GForce 4 speed


For now, it needs to stay streetable to drive to the track as I have no trailer.

This looks nice.

A streetable, quite semi-helical dog box for the T56.

http://www.keislerauto.com/recent-news/the-all-new-road-a-track-6-speed.html

http://www.keislerauto.com/files/PPG%20Brochure%202010.pdf

http://www.streetlegaltv.com/forum/keisler-shows-off-new-dog-box-4703.html#

Pricing is high.

6G (1st thru 6th gears upgraded; Reverse remains synchromesh)
PRICE: $6,495 + $995 ASSY

4G (1st-4th gears changed out; 5th/6th/Reverse remains remains original sychromesh)
PRICE: $5,695 + $995 ASSY

Liberty Gears will take any transmission and prep it with their face plating conversion.

http://www.libertysgears.com/faceplate-proshift.htm

A ProAm Drift friend of mine was talking to them about doing a FS5R30A and they would guarantee it for a year of any type of racing. (They prep the gears and modify it to be close to a dog engagement. not so streetable).


Back in real world -

Anyone have experience with specific prepping of the stock S Chassis FS5W71C transmission for better durability? Is cryo or WPC worth while?

Has anyone tracked down part numbers to change gear ratios for a better, close ratio gear set from the Nissan parts bin? I'd like to lower 3rd gear to make it a bit easier to spin the tires and get a bit more overlap between the top of 2nd and bottom of 3rd.

[CodyAce]

There have been a few guys on Zilvia who went TKO, and one guy had his setup for sale over winter. Neat setup for sure, plus virtually bulletproof for our application. Only thing I was curious about was the clutch aspect of things with them, as who would make one to match an SR flywheel with Domestic splines? I'm sure someone could I guess, or maybe someone even offers a smaller disc to work with the pressure plate and flywheel with the right splines.

The other thing you'd need to do is convert to a Tilton style throwout bearing I'd asssume, as the factory cable stuff isn't going to work without some creativity.

[Umai Kakudo]

There have been a few guys on Zilvia who went TKO, and one guy had his setup for sale over winter. Neat setup for sure, plus virtually bulletproof for our application. Only thing I was curious about was the clutch aspect of things with them, as who would make one to match an SR flywheel with Domestic splines? I'm sure someone could I guess, or maybe someone even offers a smaller disc to work with the pressure plate and flywheel with the right splines.

The other thing you'd need to do is convert to a Tilton style throwout bearing I'd asssume, as the factory cable stuff isn't going to work without some creativity.

I think the clutch issue can be easily solved by having a custom disk made up for an SR clutch.

Differences in pilot bearing size with the transmission main shaft should be able to be addressed with a different bearing or machining the main shaft if necessary.

The throwout setup would be a requirement and part of the increased cost.

All doable, just $$$ which makes sticking with the Nissan Z32 trans more attractive.

[Matt93SE]

quick notes before I leave the office..
The road racers I've talked to have:

1. used quartermaster clutch mated to modified auto flexplate. i.e. take stock auto flexplate and drill 6 mounting holes in it to mount clutch plate.

2. use "small chevy" input shaft splines. you drill a few hundredths out of the OE pilot bearing, and buy a clutch disk to fit the Chevy splines. $150 per disk instead of $350 for the same disk with a Nissan spline on it (on top of having the input shaft custom made for a Nissan spline).

3. stock TO bearing with the center section bored out just a tiny bit to fit over the F5 snout. Or you could go to a hydraulic TO bearing supplied by lots of places. Just be sure to install remote bleeder lines while you're doing the work to make life easier later.

4. there are lots of places that build custom bellhousings or modify stock ones to fit trannies for road racing apps. I've seen a couple out there for SRs, but VERY few (i.e. none) for KA in my search for a dog box for my KA. If you talk to the tranny manufacturers, they offer some bellhousings to order. they keep stuff like LS1 or Miata or RX7 engines in stock due to the popularity in road racing, but the SR just isn't that common here to make it worth their money to keep a ready-made unit on the shelf. BUT they have the dimensions on file and can often make one in a few weeks from drawings and a core bellhousing.

One guy I talked to up in WA uses the KA24DE in a mini-sprint dirt car with a G force T5 behind it. he said he'd make a KA-to-T5 an adapter plate for me for $250. cheapola!! Now I just wish I could remember his name and contact info!

[Matt93SE]

addendum..

http://prodracing.com/prodcar/viewtopic.php?f=4&t=12676

there you go. new bellhousing and your problems are over.

[Def]

They are when you go above 200whp and put slicks on the car.
I have at least 50hp to go and I don't run slicks.

Still don't see how that really stresses the trans more. Some people are just hamfisted beyond reproach, which I think is the root of the problem.


I've usually found people that munch transmissions to have extremely poor heel and toe skills, so they shock load gears on every downshift far far more than you'd get putting even 300-400 rwhp through the trans. If they're also breaking straps on pressure plates then the downshifting is more to blame than power or how much grip your tires make.


200 rwhp is super easy to put down even in 1st gear, don't see how a stickier tire is really going to matter much on trans life.

[Matt93SE]

The road racers usually break the baulk rings, and it almost always happens under decel. As soon as you let off the gas from +200hp to engine braking (let's just call it -200hp), you have a huge shockload while the rear suspension is still loaded and the sticky tires are stuck to the track, and the engine is trying to go the other way.

So haul ass down the straight, lift & brake, do 3-2 downshift, turn in, roll onto gas and exit corner. upshift from 2-3 and you've got nothing but air for 3rd, but everything else works.
finish the race without 3rd gear and pull the tranny.
toss in spare tranny, go back to racing. hope you finish.

When you get home and open the case, you find the 3rd gear baulk ring in 3 pieces in the bottom of the box. replace. repeat.

The fast guys say to plan 2-3 races on a stock tranny at those power levels before needing a new ring.

For a while, some places offered steel baulk rings, but those are since gone and the guys going that fast have gone to T5, Taylor, Quaife, or Jerico.

[PoorMans180SX]

Also, urethane mount your engine and trans, get a solid subframe bushings, and a one-piece driveshaft.

I'm pretty sure all the slop bouncing around after your clutch kick doesn't help.

[Matt93SE]

Actually the softer mounts can sometimes help since it gives the shock a place to go and lower the impulse... As long as you don't run into wheel hop issues, which makes things 10,000,000,000% worse.

[Umai Kakudo]

I have the drive train slop mostly contained.

JGS motor mounts and Peak Performance Red trans mount keep the engine / trans in place.

Have the stock drive shaft with worn out guibo and the sub frame collars are starting to get some play but no wheel hop thanks to sphericals all around in the back.

The Taylor gearbox is a really good unit (45lbs and drop gears designed for up to 2L engines) but I'm betting it is not rated for the higher torque of a turbo 2.0L.

http://www.taylor-race.com/pdf/catalog.zip

I think the Mini Sprint KA24DE guy is Kevin and lives a few miles from me. I'll have to ask him! He was building his own chassis for a GT2 VG30 powered S13 hatch. He was using a standard FS5W71C for that one to start with I think.