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What's a 1.8i MX-5 Engine & Gearbox like
Guinness - 22/8/09 at 03:13 PM

Spotted an MX-5 which has failed it's MOT with a buggered diff. It's a '96 reg and is up for £350.

Stock power from the 1.8i is quoted at 131 bhp. Is that realistic and can it be improved?

What is the gearbox like in terms of shift? Better than a type 9? Can they cope with more power? (I know Claire is running 200 horse through hers).

Will the box fit down an Indy tunnel and the engine under an Indy bonnet?

Cheers

Mike


graememk - 22/8/09 at 03:20 PM

i have a nissan engine and silvia gear box in my indy


zilspeed - 22/8/09 at 03:33 PM

Dave1888 has just done an MX5 engine/box conversion into his Tiger.

Gearchange is lovely - like a rifle bolt.


martylemoo - 22/8/09 at 03:51 PM

Gearboxes are perfect and can easily handle 200bhp.

I have a Mk1 1.6 running 200bhp via a Sebring/JR supercharger kit and an Emerald ECU and its the nicest power delivery i have ever experienced. In a kit car it would be simply awesome.

Torsen LSD's can be had for little money as well which transform the power delivery.

I would say go for it, check out http://mx5heaven.co.uk/
They now specialise in donor packs for 7 'esque' cars.

If you have any tuning questions regarding Mx5's chuck them my way, I have been tuning these engines for over 12 years now.


irvined - 22/8/09 at 04:25 PM

MX5 Engine/Gearbox combination is lovely, gearchange is wonderful, engine pulls well from low down, but really picks up at revs, both items are bulletproof.

As has been mentioned, you can get bolt on turbo/supercharger modifications for reasonable money, bringing you well above 200hp.

Flyin' Miata do/did megasquirt off-the-shelf units for aorund $800 which gave an additional 20hp at 6500rpm on my 1.6 , and enables you to remove the air flow meter and replace it with a simple map sensor.

Spares are plentiful, as you wont get a diff you can either go for a standard sierra item, as its a bit more compact, or grab a viscous LSD for around 120quid from one of the mx5 spares companies.

You can get various torsen upgrades that fit the stock diffs, rather than paying over the odds for an original torsen from a 1.8.

BTw, check that the diff is actually knackered and not just fitted with a torsen as they do clunk and click especially when reversing.

Cheers


David


Guinness - 22/8/09 at 04:34 PM

Cool!

Sounds like it'll be worth a look at least.

Dave1888's blog is interesting and show that it fits in the chassis. It doesn't seem to show being updated since the physical install though, so wondering how it runs.

Cheers

Mike


l0rd - 22/8/09 at 08:28 PM

That would be a good donor for me if it was closer


iti_uk - 23/8/09 at 06:26 PM

It's a good combo, as has been mentioned, the gear shift is rifle-bolt-like and the 1.8 begs to be force-fed.

Everyone over here seems not to know about the weakness of the mx5's 5-speed. It can hold up to around 230lb.ft reliably, but you'll be wanting the quaife gearset or swap for the 6-speed if you go any highr than that.

Check forum.miata.net for detailed mx-5 info. Really good site.

Chris