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MX-5 6 speed gearbox does it replace type 9?

Fcck2000 - 14/11/14 at 12:12 PM

Hi All,

I'm currently running a Tiger Supercat with a Mazda MZR engine.

As it's the winter I was thinking of fitting the 6 speed Mazda gearbox from an MX5 Sport, I know the bellhousing will fit because this is the car the engine came from. The gearbox does look quite a bit bigger and I believe it sits at an angle of 10 degrees. Other than that I'm a bit in the dark.

Has anyone fitted the Mazda 6 speed box to a Duratec MZR engine in a Tiger Supercat or similar? Would be interesting to know how the setup works and if it's worth the effort removing the type 9.

Thanks
Paul

pewe - 14/11/14 at 12:23 PM

Don't know about compatability but IIRC the 6 speed Mazda box ends up with almost the same top gear as the 5 speed.
That poses the question as to whether the Mazda box will give any advantage compared to a Type 9?
Just a thought.
Cheers, Pewe10

Fcck2000 - 14/11/14 at 12:36 PM

Thanks for the reply, thing is I'm concerned that the type 9 (standard) in my car is going to let me down at some point because we are pushing it over the estimated power level of 180bhp.

I've had a really bad year in regards to things breaking and spoiling track days so I'm wanting to use the winter to do all I can to make sure I'm driving not fixing at events next year. It does seem that the 6 speed Mazda gearbox has more strength than a standard type 9. From what I've read the syncros are different which makes for quicker reliable gear changes.

I also like the idea of 6 gears :-)

kingster996 - 14/11/14 at 12:38 PM

I'd get the type 9 sent off to BGH - long first gear and bearing upgrade - good for 240bhp and much more useable first gear.

It's what I'll be doing soon!

CNHSS1 - 14/11/14 at 01:21 PM

Jeff with the supercharged Fury ran a Type nine with eleventy thousand hp on track, probably worth dropping him a line for his thoughts

Fcck2000 - 14/11/14 at 01:27 PM

I'm getting the impression that the thoughts are to stay with the type 9 gearbox with upgraded internals.

blakep82 - 14/11/14 at 01:31 PM

quote:
Originally posted by Fcck2000
I'm getting the impression that the thoughts are to stay with the type 9 gearbox with upgraded internals.

Thats what I'd go with
Also remember that the 180bhp, I think, was suggested as the maximum for a sierra. Your cars a lot lighter. Could probably take 1000bhp with no axle or load connected

mcerd1 - 14/11/14 at 01:49 PM

quote:
Originally posted by Fcck2000
I'm getting the impression that the thoughts are to stay with the type 9 gearbox with upgraded internals.

if the engine is designed to be tilted at 10° and its attached to the correct box that achieves this and is also strong enough for the engine - then I'd the only problems I can see are whether or not it fits in the space you've got and getting a custom prop / mounts made

someone posted the rough dimensions for the 6 speed box a while back, but I can't find the thread...

quote:
Originally posted by blakep82
Also remember that the 180bhp, I think, was suggested as the maximum for a sierra. Your cars a lot lighter. Could probably take 1000bhp with no axle or load connected

^^ 145bhp is the suggested limit for the 2.0 type 9 in the sierra (its torque that kills them really, but its harder to get figures)
BGH quote same limits for both the stock and modified boxes on there website

in lightweight cars folk seem to use them up to 180/200bhp without issue, some folk have used them all the way past 250bhp in stock form but that's taking quite a big risk...

[Edited on 14/11/2014 by mcerd1]

cliftyhanger - 14/11/14 at 02:08 PM

I am a bit confused by the replies.
It seems that most people are against the swap, but why??

OK, it means a few changes to prop, mounts etc, but the mazda box will be stronger, and it may have better gear ratios??

I would say if the ratios are good, go for it. Probably as cheap as getting the t9 upgraded...

Fcck2000 - 14/11/14 at 02:36 PM

quote:
Originally posted by blakep82
Also remember that the 180bhp, I think, was suggested as the maximum for a sierra. Your cars a lot lighter. Could probably take 1000bhp with no axle or load connected

To upgrade a type 9 gearbox could cost me in excess of a grand, having spent that money I still could break it which then puts me a couple of thousand out of pocket.
Fitting a newer modern box that can be bought for Ł350 all day long seems a much more practical option. The cost of the new box could be recouped with the sale of my type 9 and bellhousing.

I guess it's more a case of will one actually fit in the space I have and will the box be OK as my engine and sump are mounted square, making the gear lever angle over is no real issue.

Agreed it is torque that kills gears although gear changes at high rpms kill syncros. From what I understand the Mazda box has a triple syncro system to allow for faster gear changes without the crunches.

Paul

coozer - 14/11/14 at 03:17 PM

I'd stick with the type 9, the Mazda 6 speed box is very heavy and the extra cog isn't worth the work involved in the swap. New clutch, prop, mounts etc...

Although you have 180 bhp the car is lighter, not as much mass to accelerate so the box has an easier time.

Ring gbh and discuss the ratios that will make the car easier to drive!

Ugg10 - 14/11/14 at 03:40 PM

MX6 ratios type 9 Std Type 9 Long 1st

1 3.76 3.65 2.98
2 2.27 1.97 1.97
3 1.65 1.37 1.37
4 1.26 1.00 1.00
5 1.00 0.82 0.82
6 0.84

Info from - http://www.miata.net/garage/KnowYourCar/S8_Gears.html and http://www.bghgeartech.co.uk/html/5_speed.html and http://www.type9gearbox.co.uk/type-9-production.html

There are two reasons for replacing the type 9 - too much torque/power which will kill the box and also the very short 1st and big gap to 2nd.
The MX5 box may help the first issue but does nothing to solve the second.

Given the hassle of fitting this box as mentioned before (possibly chassis fouling, prop, new mounts, clutch conversion, speedo drive etc.) for a similar cost you can have a BGH long 1st Heavy duty than can be swapped in an afternoon. (other long 1st are available if you search). I suspect both will be a similar price (around Ł1k) to do.

Fcck2000 - 14/11/14 at 04:19 PM

Thanks for taking the time to search that info.

From what I understand Caterham, Morgan and some others are using the Mazda boxes without any failure issues. I know it's going to take time fitting but could be worth the effort.
Having a 1k rebuilt type 9 old technology gearbox compared to a brand new from Mazda box for Ł1400 odd seems like a no brainer even with the effort to fit it.

Ugg10 - 14/11/14 at 05:31 PM

Haven't a clue how easy/hard it would be to fit but have you considered the T5 out of the Sierra 2WD cosworth/TVRs.

Ratios seem to be better -

1st = 2.95:1
2nd = 1.94:1
3rd = 1.34:1
4th = 1:1
5th = 0.80:1

Ford Sierra Cosworth 2wd T5 Gearbox

Dimensions for T5 and Type nine in here - http://www.locostbuilders.co.uk/viewthread.php?tid=167973

Not sure hat you would need to do but these guys do an adapter fit the duratec to T5 - http://www.mulfab.co.uk/our-products/7/other-miscellaneous

radom - 14/11/14 at 08:24 PM

quote:
Originally posted by Ugg10
MX6 ratios type 9 Std Type 9 Long 1st

1 3.76 3.65 2.98
2 2.27 1.97 1.97
3 1.65 1.37 1.37
4 1.26 1.00 1.00
5 1.00 0.82 0.82
6 0.84

The MX5 box may help the first issue but does nothing to solve the second.

I don't know, mx5 ratios still look better even when compared to type9 with long 1st IMHO

Ben_Copeland - 14/11/14 at 08:34 PM

I'm running a type 9 in mine. Power and torque figures above my picture. It's been fine this year, don't forget your pushing around a lot less weight than a Sierra

Jenko - 15/11/14 at 07:14 AM

Another vote for sticking with the type 9, many, many people are running much more power than 180bhp, they are very under stressed in our tiny light cars.

jeffw - 15/11/14 at 07:45 AM

I run a BGH E8 Alloy cased Type 9 in the Phoenix. The engine produces 397BHP & 300ft/lb in 610Kg car. The car is used extensively for Sprinting and trackday as well as occasional road use.

I've nuked the gearbox twice this year, on both occasions it let go while changing gear over a bump, so failed under shock load. It will deal with the power but not shock load and power at the same time.

If the Mazda box will fit then go with that otherwise a BGH E6 will do everything you want for a long time to come.

Furyous - 15/11/14 at 09:01 AM

I went with the MX5 5-speed for my Duratec install. I snagged it for Ł125 just before Christmas a couple of years ago.

The type 9 had sloppy feeling gear changes but the MX5 box has a very nice click-clack bolt action feel to it. That may have just been my particular Type 9, though. The N7 is a fair bit bigger than the Type 9 and it's a tight squeeze in the transmission tunnel, compared to bags of space with the Type 9. The main issue I had mounting it is that it's quite "tall" so it almost ended up hanging under the chassis whereas the Type 9 was a couple of inches above. The N7 bellhousing is wider than the ones used for Type-9 to Duratec mounting, which means less ground clearance. I think the Raceline sumps would end up being a bit higher than the bottom of the bellhousing.

I'm pretty sure the 6 speed has a bigger housing, and it weighs more. But the gears are shorter and the final drive is pretty much the same as the 5 speed.

Clutch, flywheel and starter are easy to work out. You just use MX5 parts. No need to mix and match different bits. Bear in mind the MX5 clutch is hydraulic and the Type 9 is (probably) cable.

Using the N7 box made the install a bit awkward but I don't regret using it.

5 Speed Ratios:

1 - 3.136
2 - 1.888
3 - 1.330
4 - 1.00
5 - 0.814

[Edited on 15/11/14 by Furyous]

Fcck2000 - 15/11/14 at 09:11 AM

good to hear from someone using the mx5 box. Ł125 is a right bargain... Sounds like you are happy with the mx5 box and it was worth the effort.

johnH20 - 15/11/14 at 07:02 PM

I have just weighed a spare MX5 5spd on my scales ( bathroom ). It is 34 kg incl integral bell housing. Not sure how this compares to a 6 spd but that is unlikely to be more than 40 kg I would have thought. FWIW the concensus in the MX5 community seems to be that the 5 spd has a sweeter shift than the 6 spd. Certainly my experience too. Hope this helps your decision.

mcerd1 - 16/11/14 at 12:02 PM

quote:
Originally posted by Ugg10
Haven't a clue how easy/hard it would be to fit but have you considered the T5 out of the Sierra 2WD cosworth/TVRs.

T5's are stronger, but they were never fitted to that many cars in the uk

also the cossie and TVR boxes are quite different - the TVR box is a version of the 'world class' ones that are used on loads of American muscle cars (at least the 'stick shift ones)
the cossie box is the non-world class version that was only really in rwd cossie's and have different ratio's too

also I notice that those adapters need an MT75 bellhousing to suit the engine
do they mean the FWD MTX75 box or one of the very expensive aftermarket removable MT75 ones ?

if it comes to it you can modify a type 9 bellhousing to fit a T5 without too much trouble (depending on the space available on the casting) and its probably easier than finding the right MT75 bellhousing

Fcck2000 - 16/11/14 at 12:50 PM

quote:
Originally posted by jeffw
I run a BGH E8 Alloy cased Type 9 in the Phoenix. The engine produces 397BHP & 300ft/lb in 610Kg car. The car is used extensively for Sprinting and trackday as well as occasional road use.

I've nuked the gearbox twice this year, on both occasions it let go while changing gear over a bump, so failed under shock load. It will deal with the power but not shock load and power at the same time.

If the Mazda box will fit then go with that otherwise a BGH E6 will do everything you want for a long time to come.

I called these guys on Friday after coming across them on the internet http://vitesse-ltd.com/
Spoke to a guy called Tim who was very happy to look at my car to see whether the 5 speed or 6 speed gearbox would fit. Apparently they've been supplying Morgan, Caterham and others the Mazda gearboxes for some time now and with great success. From what I understood they've supplied hundreds without a single failure! Tim did say if I took my car over to them they would have a look and advise the parts required to use either the Mazda 5 speed or 6 speed whichever would fit.

Having looked at your post with 2 gearbox fails in one season it might be worth also giving them a call. I was quoted roughly Ł1100 for a 5 speed Mazda box and Ł1400 for a 6 speed Mazda box, both would be brand new items from Mazda.

Edited because my facts were wrong...

Paul

[Edited on 16/11/14 by Fcck2000]

Ugg10 - 16/11/14 at 03:49 PM

quote:
Originally posted by Fcck2000

quote:
Originally posted by jeffw

5 speed Type 9 BGH E8 weight 72kg (possibly more with all the upgraded internals) Ł2200
5 speed Mazda weight 45kg Ł1100

Interesting weight on the bgh box. I put my standard type 9 plus zetec se ally bell housing and clutch frk on my scales and got 36kg. So less than the mazda.

Fcck2000 - 16/11/14 at 03:57 PM
Indeed you are correct, well spotted and thanks for pointing out.

Just checked and I was reading lbs not kg. Looks like the 2.8 type 9 is 45kg but a standard one is 33kg

info from here
http://westfield-world.com/engineandtransmission.html

johnH20 - 16/11/14 at 05:17 PM
Ugg 10, Where did you get your 45 kg for a Mazda 5 speed? As above I weighed mine at 34 kg, I don't believe my bathroom scales are that far out! Also used Mazda 5 speeds are as cheap as chips due to the number of MX5s being broken due to rust. Anything more than Ł100 and you are being robbed.

Fcck2000 - 16/11/14 at 05:28 PM
Mk3 MX5 ;-)

Sam_68 - 16/11/14 at 06:43 PM
quote:
Originally posted by Furyous
I'm pretty sure the 6 speed has a bigger housing, and it weighs more. But the gears are shorter and the final drive is pretty much the same as the 5 speed.

I can confirm that the Mazda 6-speed is a big beast... much heavier and bulkier than the Mazda 5-speed. I've not weighed one, but I can say that it's groin-strainingly heavy compared to the 5 speed.

Also plenty bulky enough to cause problems with the tunnel width on a car that's not been designed for it.

Here are CAD drawings of the two boxes, for comparison (6 speed is at the top in both instances):

Fcck2000 - 16/11/14 at 07:20 PM
excellent thanks for posting those. 5 speed looking like the most practical option

snakebelly - 16/11/14 at 11:53 PM
Were just putting a Mazda 5 speed in our Supercharged Duratec Tiger GTA, it didn't slot straight in but apart from some lateral thinking re the gearbox mount it went in ok. It does end up slightly canted but everything I have heard seems to be that that's fine. As others have said the cost was a big factor as we only paid Ł89 for a 5 speed out of a 38k crash damaged car and it looked like new! We bought a complete flywheel and clutch package from retro Ford but even paying for that, the box and a new slave cylinder and starter we had change out of Ł700. And if we break it then for another Ł100 ish ill happily keep a spare box under the workbench!
HTH