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Archives of Posts to the NZ MX5 List back in 2005
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Mark O'Sullivan

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Post by Mark O'Sullivan » Tue Nov 22, 2005 8:46 pm

Try this for transferring MX5 running gear over:

Take a modified Mazda MX5 engine (176 bhp at 8,600 rpm), 5 speed gearbox and
Ford 4.11 diff and stitch into a Lotus 7. Curb weight 510 Kg.

Original engine was an 86 bhp 1600 pushrod Ford Crossflow.

Have just come back this evening after a drive in this 7 courtesy of it's
owner...100k in 4.4 seconds plus handling similar to a racing go-cart.

Unreal.

Cheers
Mark

Euen
I am quitting my job and going 5-ing
I am quitting my job and going 5-ing
Posts: 619
Joined: Tue May 23, 2006 9:42 am
Location: North Shore

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Post by Euen » Tue Nov 22, 2005 10:30 pm

Sounds impressive Mark. That power to weight ratio would make a big
difference.

Do you know what has been done to the engine? I guess the hydraulic lifters
have gone if he is taking it to over 8000.

Cheers
Euen
TG Sports, classic roadster - modern technology. NA1800, 99 head, 11:1 +2mm Wiseco pistons, Link LEM, Alloy f/wheel, JR headers.

Mark O'Sullivan

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Post by Mark O'Sullivan » Wed Nov 23, 2005 6:32 pm

Hi Euen

The MX5 engine runs 2 twin sidedraught carburettors with 40mm chokes - (yes
carbs) - mounted on a custom built inlet manifold with a custom built air
filter box on the side. Most of the electronics are gone. The head is ported
and polished, sodium filled exhaust valves lapped onto competition valve
seats, with high lift high duration cams and custom built headers. The
lifters are solid. Idle speed is near 1,800 rpm.

How much did these mods cost? Please don't ask.. Apparently the MX5 engine
was chosen as the basic starting point because it's way over-engineered in
the first instance and is very light for the potential power developed -
just right for a Lotus 7.

Fastest car I've ever been in - and the roar and spit-back sound those carbs
made was as unbelievable as the pressure under acceleration and on
cornering. Was like being in a jet fighter on wheels.

Cheers
Mark

Euen
I am quitting my job and going 5-ing
I am quitting my job and going 5-ing
Posts: 619
Joined: Tue May 23, 2006 9:42 am
Location: North Shore

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Post by Euen » Wed Nov 23, 2005 6:54 pm

Thanks Mark

Is it a 1600 or 1800? What part of the country is it in?

I agree on the sound of twin side drafts. Under acceleration they are one
of the nicest sounds in motoring.

Cheers
Euen
TG Sports, classic roadster - modern technology. NA1800, 99 head, 11:1 +2mm Wiseco pistons, Link LEM, Alloy f/wheel, JR headers.

Badcat
Need, more, 5-ing, time....
Need, more, 5-ing, time....
Posts: 158
Joined: Thu May 18, 2006 10:24 pm
Location: Auckland city

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Post by Badcat » Wed Nov 23, 2005 7:27 pm

have you ever seen an mx5 with 4 keihin FCR motorcycle flatslide carbs
(41mm) ?
i drove one is hong kong and it was incredible.
it had slotted cams, headers etc and felt a LOT stronger than standard.

k


On 23/11/2005, at 6:54 PM, Euen Burke wrote:

[...]

Mark O'Sullivan

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Post by Mark O'Sullivan » Thu Nov 24, 2005 4:43 pm

Hi Euen

The engine is a 1600 I believe, but I'll double check on that one - and the
car is in Auckland. The car is not a 7 replica - it's a Caterham 7 imported
from England.

I've got some interesting info from Peter at Fraser Cars on Auckland's North
Shore. (Fraser build replica Lotus 7 Series 3's that are faithful to the
original design). He's told me that Mazda MX5 running gear for their cars
are becoming a more attractive option - as the 1600 Toyota 4AGE engine as
very often used has a problem - they are a front drive engine and require a
bell housing for the gearbox out of the early rear-drive GT Corolla - which
are becoming very scarce.

With the MX5 you already have the engine already running North-South with
the right gearbox already mated - and you can use the diff assembly from the
MX5 as well - and it's lighter than the usual Nissan Skyline/Sylvia set up
they often use. And MX5 running gear is much easier to get hold of.

Fraser will basically build what you want to your specification. If you
want carbs they will give you carbs - and will assist to build the engine to
any state of tune you want. They have already built a few 7's with MX5
running gear - one is an 1800cc version running after-market EFI - it goes
very well.

Check out their website at www.fraser.co.nz

The only drawback is the price of the cars - in the region of $45,000 for a
brand new one ready to drive away out of the factory. But you can cut the
cost substantially if you buy one of their kits and build the car yourself
and supply the running gear.

Hope you find this of interest Euen. You can look at it this way too - it's
a way of resurrecting the soul (running gear) of an MX5 that's been
terminally accident damaged.

Cheers
Mark

Euen
I am quitting my job and going 5-ing
I am quitting my job and going 5-ing
Posts: 619
Joined: Tue May 23, 2006 9:42 am
Location: North Shore

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Post by Euen » Thu Nov 24, 2005 6:04 pm

Thanks Mark

I guess you could say that I am going the "Alternative" route. My project
is a MG TF replica produced by Altenative Cars down in Onehunga.
http://www.sportscars.net.nz/

This uses the full set of MX5 running gear. I guess it was intended for
more sedate motoring however mine is planned to be a little different.

I know of Frasers, they are just around the corner.

Cheers
Euen
TG Sports, classic roadster - modern technology. NA1800, 99 head, 11:1 +2mm Wiseco pistons, Link LEM, Alloy f/wheel, JR headers.

Mark O'Sullivan

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Post by Mark O'Sullivan » Thu Nov 24, 2005 7:56 pm

Hi Euen

Checked out the link - that's a cool project. Another ageless classic kit
car with MX5 running gear. I like it.

All the best with with this one Euen - let me know how things progress.

Cheers
Mark

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