Morning fellas,

It's been a while since my last post, and I've got the GTS covered up with a few plans for the winter.

I wanted to check what gearbox you're all running?

I originally had a T9 rally-spec straight cut box, but changed it last year to a standard T9 as the noise was noticeable for road use.

Now I've been on a few track days this year at Croft, Donnington and Cadwell, and whilst the handling and engine upgrades work well, the gearbox is becoming a problem.

The shift is clunky, and the downshift is slow, with the ratios being pretty clumsy on track.

So I was debating two potential routes:
1. Get the box rebuilt with better internals and close ratios - circa £1600
2. Replace the T9 with the 6 speed Mazda RX8 box, with adaptor plate, custom chassis mount and propshaft

Question is, has anyone done this, as I'm thinking fitment will be a close call?

Thanks!
RR

You don't say what engine ?
Better than the Rx8 box is the Mx5 N7 box. Retroford do a conversion for the zetec. The conversion is nicer and more refined than the rx8 adapter. The box is smaller and lighter than the Rx8.

I will have to find a way of uploading some photos. I have all the bits to upgrade my mt75. A great box but has crap ratios.

[Edited on 10/11/20 by big_wasa]

I put a rx8 box on my 1.8 zetec last year... massive improvement to the feel of the box and 6th gear is a bonus too.

There was a guy on facebook selling kits that included the plate and a different arm to allow use of a cable clutch.

I run a 6 speed in my car,great box but much bigger than a Type9.

My chassis was a Type9 sized chassis, I cut and smoothed loads of parts off the Rx8 box that I didn't need to use and still had to modify the tunnel in my chassis to get it in.

You will probably need to change your diff too if you want all 6 gears to be useable as first gear is very low.
I was running a 3.38 diff and first gear was a waste of time,now I'm running a 3.14 and all 6 gears are useable,although first doesn't get you down the road very far,I am running circa 250bhp though.
Sixth gear now is lovely for cruising.

quote:

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Originally posted by big_wasa
You don't say what engine ?
Better than the Rx8 box is the Mx5 N7 box. Retroford do a conversion for the zetec. The conversion is nicer and more refined than the rx8 adapter. The box is smaller and lighter than the Rx8.

I will have to find a way of uploading some photos. I have all the bits to upgrade my mt75. A great box but has crap ratios.

[Edited on 10/11/20 by big_wasa]

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The ratios on the RX8 box from 2-6 are almost identical to a quaife clubman so you could just use ratios 2-6 and leave first for really steep hill starts but with a stock 3.62 or 3.54/3.77/3.89 6th is still not a cruising gear but acceptable.

RX8

1st - 3.760
2nd - 2.269
3rd - 1.645
4th - 1.187
5th - 1.000
6th - 0.843

Quaife Clubman

1st 2nd 3rd 4th 5th
2.040 1.540 1.210 1.000 0.870
2.200 1.690 0.930
2.390

Benefits of the RX8 are that is it built for 250hp and 250ftlb (Nissan Sylvia s15 2.0l turbo) and can rev to 9k (rx8/s2000), is helical not straight cut and if it goes bang then it is £200ish to replace not £2k. Worth noting the RX8 box is an OEM version of the Aisin AZ6 which is found in a number of cars just with different bell housing elements (still integral though).

https://en.wikipedia.org/wiki/List_of_Aisin_transmissions#Longitudinal_rear-wheel_drive

Quick side by side comparison.



On the back end of a Zetec SE Puma engine





[Edited on 10/11/20 by Ugg10]

quote:

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Originally posted by CosKev3
I run a 6 speed in my car,great box but much bigger than a Type9.

My chassis was a Type9 sized chassis, I cut and smoothed loads of parts off the Rx8 box that I didn't need to use and still had to modify the tunnel in my chassis to get it in.

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If you were to stay with the type 9, i'd very strongly recommend the SPC semi helical gear kit, absolutely superb. Smooth, quiet, excellent ratio's and strong.

Of course as mentioned, the price of an RX8 box would make that route very tempting though!.

quote:

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Originally posted by Double R

quote:

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Originally posted by CosKev3
I run a 6 speed in my car,great box but much bigger than a Type9.

My chassis was a Type9 sized chassis, I cut and smoothed loads of parts off the Rx8 box that I didn't need to use and still had to modify the tunnel in my chassis to get it in.

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Hi there, thanks for the advice

I've just measured the tunnel again, it looks like it's going fowl around the gearstick end, as the wider end goes from 11.5" -9" to 8" then to 6" at the lever.

How much modifying of the tunnel did you do (roughly)

Thanks!!
RR

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If you are using a mechanical speedo or an electronic encoder on the type 9 then you will need to sort this as the RX8 box has no tachometer/Speedo output mechanical or electrical. Probably need to put magnets on the wheel hub or prop shaft.

quote:

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Originally posted by CosKev3
There is quite a lot of material you can remove off the RX8 box tbf!

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quote:

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Originally posted by Ugg10
If you are using a mechanical speedo or an electronic encoder on the type 9 then you will need to sort this as the RX8 box has no tachometer/Speedo output mechanical or electrical. Probably need to put magnets on the wheel hub or prop shaft.

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quote:

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Originally posted by Double R

quote:

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Originally posted by Ugg10
If you are using a mechanical speedo or an electronic encoder on the type 9 then you will need to sort this as the RX8 box has no tachometer/Speedo output mechanical or electrical. Probably need to put magnets on the wheel hub or prop shaft.

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Yes I was thinking about that, I have magnets on the prop so I'll probably go down that route again.

I'm really tempted by the idea of just sending the T9 box off to be upgraded but it's a lot of spend, particularly when you look at the cost of the Mazda one.

I guess the other point is, if we know the RX8 box will go in with some modification, then I'm like the idea of the challenge, especially when there's not a lot going on at the moment.

I'll get in up in the air over the weekend have another look.

Kev - did you re-weld the chassis legs back in afterward?

Thanks!
RR

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quote:

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Originally posted by lsdweb

quote:

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Originally posted by CosKev3
There is quite a lot of material you can remove off the RX8 box tbf!

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Any photos of what you've trimmed off? Ta.

Wyn

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Afternoon all,

So after all the research and hugely helpful advice on here, and garages closing during lockdown, I've finally got the Panther back on the road.

It's just having a new speedo fitted and MOT, so I'll get it back tomorrow........just in time for the sunshine

In the end I went for the SPC semi-helical gearset for the type 9 in the end, which after a bit of fiddling with washers in the gear extension works really well. I also had a rebuilt ST170 unit installed with 285 piper cams and a stage 2 head, after a remap it should go pretty well!

Thanks again for all the help - just can't wait to get it out for a blast.

Who else is out this weekend?

RR