Will the 6 Speed hold up to....considered discussion
 

I have a new project in mind..

For ages I have wanted to play with reliable 250 + HP, 10" wheels and front and rear Aero and strip out weight etc. The class I race in won't allow aero etc but will in the invitation class, which is the almost anything Japanese goes class.

I figure I will build an all out race only car (unlike current car that is still road capable and legal) and have a bit of fun with the build.

Now that Trackspeed have the superlight brake package it is pulling me even closer.

So in the interest of NON turbo related issues I want to run a VVT Toyota V8 WITH the mazda 6 speed.

before you all start on the "why waste your time just go LS" bandwagon...this is why.

1. LS motors outside of the US are VERY expensive

2. LS motors outside of the US are very rare.

3. LS Motors REQUIRE a stronger Diff and Gearbox, not to mention a lot of fabrication etc associated.

4. I want to stay in the Classic Japanese class

5. Toyota VVT motor is not expensive, is not rare

6. Toyota VVT puts out a proven (with a megasquirt) OEM 300 HP and 300 ft lbs at the wheels.


further reasons are IF we can mate the motor to gearbox, the rest of the installation is easy. i.e. oem diff, retain PPF etc.

So, thoughts and comments on whether the gearbox and / or diff will hold up to the power curve of a 300 hp 300 ft lbs v8?

It will be a reasonably driven race car so it wont be abused like a drag or drift car with burnouts etc, though we do do standing starts.

I don't have any problem with the toyota v8, and it will likely hold up at those levels (though close to the limit on a race car, but then you'll be light so it might still hold up)

but

why a v8 for only 300? surely there are smaller engines that can achieve the same reliably even in n/a trim?

What's wrong with the Toyota gearbox? Custom driveshaft, done.

Diff will be fine.

I would not expect a Miata 6-speed to hold up to 300wtq for very long.

has to be japanese for the class and available here, remember its totally different to there.

Also, heaps of info on how to fit motor to car, so should be relatively easy. Mazda v6 seems like a hassle and hard to get. Honda's are okay but I race against heaps of hondas so would prefer to not join that crowd...Also the kits are hellishly expensive once $, freight and customs etc factor in.

hmm, this is my concern.

My hope is that it would last a season or two...then stage 2 if/when it did prove to be a problem would be to look at a toyota gearbox.

Glad to hear the diff should be okay.

custom gearbox mount, custom diff mount, chassis bracing .....toyota gearboxes here are $2,500.00, the motor is only $1,900.00 (NZ $)

appreciate the input so far, thank you.

300 wheel torque 4th gear in the 6 speed will not like. been there done that multiple times over and over.

Bbundy, thank you.

As an avid reader of the gearbox thread I know this is an ongoing problem...my hope was that the torque curve of a lower power V8 being a bit more progressive than most turbo cars would / will have a positive impact on longevity.....

you dont think so?

There was talk about lighter flywheels being harder on the gears. The smoother power delivery of a v8 should make a difference, but how much?

Could you tune in some torque management with VVT, the initial shock of all the v8 torque is probably what will break everything.

Are W58 and R154 trans expensive/rare in NZ? Folks put those behind 1UZ motors all the time.

Edit - It appears they are. Reading comprehension fail...

Adapters can also be had to run the Nissan S13 or Z32 300zx 5spd trans for toyota v8's.

Wait, LS are really hard to come by in upside down land? I thought you guys had a shitload of Holdens over there packed with ls juans.

Sadly, they are one of only 2 main brand v8 vehicles (ford Falcon the other) so the vehicles are treated like holy grails are not especially plentiful to start with, then when any do reach the wrecker or whatever, other Holden owners want them, hot rod builders want them and so on....so they start at $7-10k plus IF you can get your hands on one....and that's just a used 100km or more motor.

but, LS (GM) isn't in keeping with our classic Japanese class, build cost escalates rapidly, other drivetrain costs escalate etc...as per original post.

I don't think the big factor is shock loading it is more fatigue loading of the teeth under load. It is time spent at full torque in a particular gear. lube choice or shock additives also have little or no impact on it. Run full throttle down a straightaway and the individual teeth are receiving ~ 5000-7000 full load cycles a second as the rpms sweep through the high torque range of the powerband. I've never had one pop upon a shift or any jerkiy type shock event such as landing off a yump or bump at full throttle its always been in a straight line pull with revs climbing through the power band on a smooth high grip straightaway.

As a data point, I killed my 6-speed in the same way (4th gear pull through the torque peak).

300tq from a V8 will be easier on the transmission than 300tq from 4 cylinder. Average torque of 300 will be the same, but the peaks will be lower from a V8 since it has more cylinders firing.

I'm running a stock 18lb flywheel on my 6 speed to keep the 4 cylinder torque peaks as dampened as I reasonably can.

all of this wont be valid unless I can even get the 6 speed adapted.....and it seems like we are sort of covering off or rehashing the gearbox thread....

I guess that leaves me somewhat hopeful as there is some doubt how long it will last (worst case) or that it MIGHT be okay if the power delivery etc is any smoother or delivered different in any way.

At least its not a flat out, "it will blow apart in 3 laps time" ... (though it still might! :) )

I think at this point i'm going to hope that BBundy's and others (the few others circuit racing with 300 ft lbs or more) experience will at least give a year or so of use.....it will certainly beat bashing my head (and wallet) against a brick wall with all sorts of messed up engines in the turbo route..though wouldn't you know it we are close to getting a handle on that now...

Stay tuned... it MIGHT be interesting....

I do wonder if it does work out, whether its not a reasonably low cost, mid power option for people...I mean a 300 ft lb, 300 HP at the wheels mx5 is going to be a bloody quick little car.......which most importantly, if it can be done retaining oem gearbox, ppf and diff....WITH an OEM Motor (a relaible as all f**k toyota at that) seems pretty good to me.

How much are wrecking yard 1uz vvti motors going for in the US?

Can't you run a restrictor on the V8, combined with tuning, to keep the torque down to 250 or so? That should take care of your durability problem.

I see so many Utes running around down here, didn't think LS's would be so expensive. But if GM-Holden isn't selling them as a crate motor then that puts a real hurt on the supply.

People in the UK and Russia have mated 1UZ's to the IS200 / Altezza 6 speed box, which happens to be the same box as the Miata. I was thinking of going the same route (I own a Lexus IS200 which is terribly underpowered), but I am not sure about the gearbox. For street use I guess the box will be fine as is proved by people in the UK running IS200s/Altezzas with this combination. I would like to occasionally track the car and I do not want return home on a trailer though.
I am on the lookout for a R154 box ever since, but they are not cheap in Europe either. There are not much gearbox alternatives for the Lexus as it has quite a cramped transmission tunnel and I do not want to cut the tunnel. Alternatives are a W58 and V160 / V161, but the W58 is a bit old, weak and clunky whereas the V160 / V161 costs as much as a complete decent replacement car.

As for mating the 1UZ to the Miata box: that might be possible by swapping the front of the transmission case from an Altezza / IS200 and buying an adapter plate from one of the fabricators in the UK. Shipping to NZ might be expensive though...

1998-2000 LEXUS GS400 SC400 LS400 4.0L ENGINE JDM 1UZFE VVTi MOTOR 1UZ | eBay

Looks to be about 1300-1500ish.

Just out of curiosity, are either of you guys using external trans fluid coolers?

Kmiata... Calling Kmiata....

:idea: That would probably be the best bet.

its obvious 2jz is the answer to all things


jk its a heavy pig and does not belong on the track.

+1 for k miata

yup agreed, Kmiata sounds like the better option here.

Is this a RHD car? If so, our swap still requires some fabrication. We don't have a full RHD swap kit (yet). It will happen eventually.

But a K is perfect for the 6 speed. 300whp is easy, and with 200-210wtq or so.

we considered a K, but k's are $4k or more here....same old issue, kit costs....well whatever it is, double that for the exchange rate, add a few hundred for freight, then 15% sales tax and then another $200.00 or more for customs duty....just gets too expensive.

you guys just don't know how good you have it....9" 6uls cost $1500-$1700 to land here...makes me cry....

Then again we don't have guns so maybe not so bad :inout:


Interesting info on the altezza 6 speed, will look more in to that....thanks.

So you can't even shoot somebody if they had all the parts you needed?

What a world.

Yeah, the import expense is really the issue.

This why we'll complete an LHD NC swap kit before we spend any time on the RHD kits. I think there is lots of interest, but its cost prohibitive in a lot of markets.

Sounds like your country hates my two favorite hobbies.

Does anyone know anything about cyrogenic treatment? It sounds like a good system. I am going to call some places Monday and chat with them. It sounds like it might work even for rear hubs and brake rotors. The link below only shows up as" transportation" for whatever reason

Transportation

Both cryo and REM-ISF treatments are aimed at getting the last few percentage points of life out of a trans/driveline. It's not going to make a huge difference.

Sense torque seems to be the issue with the six speed, mainly 4th, I thought that the section at the bottom of that article was very interesting about that scraper diff. They are saying 7 times the longevity out of brake rotors, that is pretty significant.

I wonder why we haven't just tried to target 4th and make a afterwork 4th gear set from like 300m or some other high strength gear steel. Shot peen,cryo,rem finish it and see if the trans will hold the 300 ftlbs.

There has been a lot of talk of full gear sets, but i only see the gear sets selling to a limited number of people. Most people don't wanna drop $4000 on gears and another $1000 on install.

It always comes down to the overall package.

Sure its possible to make an AZ6 gear set in a Miata case that can handle 400 plus HP reliably. But it will cost as much as a T-56 or TR6060. At which point you just spent a big portion of a swap budget to build a driveline sitting behind a BP that has pretty massive reliability issues anywhere over 300HP. You either build it right with a lot of $$$ or you blow it up, or you only use it for street duty. And there are dozens of cars (including NCs) that will make for better high-HP street cars than an NA or NB. Almost nobody is interested in transmissions beyond 300WHP for a street driven BP car.

So lets swap some other trans in there and go for a cheap solution. As outlined in painful detail by Sav, that is really hard to do while retaining the kind of gearing that is exactly what guys with 300+ WHP NAs and NBs want on track. Thinking of the T5 here. And you still wind up spending at least another $1000 over the cost of another 6 speed to get inferior gearing.

You either spend a lot of cash to retain an inferior power plant, or you spend a moderate amount of cash to retain an inferior power plant with some customization hassles and inferior gearing.

The 4th only idea is interesting, but I really wonder what happens when you fix that one issue. Does that same trans fail 3 races later because XYZ? Does 3rd give up? The vast majority of 6 speeds that have failed have just been scrapped or lie in piles next to garages. Very few have had a new 4th thrown in to see what blows up next. 4th might be acting as a fuse and the other may not be far behind. Considering the ratios, that actually seems very plausible.

K swaps and brotrex's may well be the way to go if you want a 400WHP NA or NB that does not shatter 6 speeds all the time, because lower TQ, while retaining some pretty amazing real-world track performance.