lightweight mx5- how far can you go to stay road legal

lightweight mx5- how far can you go to stay road legal

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Discussion

covmutley

Original Poster:

3,126 posts

197 months

Saturday 21st August 2010
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Been looking at what to do with my mx5 since one of the rear sills needed welding. Just had a simple £50 fix as car has fairly rough bodywork anyway. Have thought about using it as a kit car donor but that option is looking too expensive when you add in al the extras- van hire, IVA, powdercoating etc...

Now looking to strip it to get a little more power to weight, because I like the look and can perhaps sell some bits towards a turbo setup or just to pay for extra track days.

Main question is whether something like in the photo (no windscreen/windows) below would pass an MOT? I would keep all lights.

http://picasaweb.google.com/lh/photo/HfqGD4C1wR7q3...


vrooom

3,763 posts

274 months

Saturday 21st August 2010
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that look awesome

mybrainhurts

90,809 posts

262 months

Saturday 21st August 2010
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Clothes horse to dry the washing...?

Inspired idea...smile

The Tea Boy

4,129 posts

242 months

Saturday 21st August 2010
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oh yes liking the pic in the link. But although you would loose alot of weight from the car, how much more bracing would be needed to keep the chassis in shape?

franv8

2,212 posts

245 months

Saturday 21st August 2010
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Looks like the next few lb's saved is for Mr walsh to lay off the burgers at lunchtime.

MrV

2,748 posts

235 months

Sunday 22nd August 2010
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The Caterhams/Atoms etc don't have them so I would say yes you would still pass an MOT with out the front screen.

Jag-D

19,633 posts

226 months

Sunday 22nd August 2010
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Hmmm I would have thought the atoms and the likes pass the MOT without them because they were originally made without them, whereas the MX5 wasn't.

I'll have a word with my tester, there's bound to be a way around it hehe

Disco You

3,694 posts

187 months

Sunday 22nd August 2010
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Detachable windscreen perhaps... Goes on for the MOT wink

Other than that perhaps replacing the panels with lighter ones?

covmutley

Original Poster:

3,126 posts

197 months

Sunday 22nd August 2010
quotequote all
My boot brake light doesn't work but gets through mot, presumably because you don't need one? Losing hood and windows would but be less practical but I only use the car when dry. Need to lose the ac first!

mAxiecAm

26 posts

171 months

Sunday 22nd August 2010
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covmutley said:
My boot brake light doesn't work but gets through mot, presumably because you don't need one? Losing hood and windows would but be less practical but I only use the car when dry. Need to lose the ac first!
The atom doesn't have a screen and thats road legal


youngsyr

14,742 posts

199 months

Monday 23rd August 2010
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Why not just take the passenger seat out, remove the roof including frame and fit a lightweight battery?

That should remove around 25 kgs without making the car significantly less useable, especially if you keep a hard top at home for wet days - the passenger seat can be put back in two minutes if you have an impact wrench.

It strikes me that after removing those items you're on to steadily diminishing returns for a lot more compromise.

Herman Toothrot

6,702 posts

205 months

Monday 23rd August 2010
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Quite a lot can be ditched if your ruthless.... I really should try and finish it.

MX-5 Lazza

7,954 posts

226 months

Monday 23rd August 2010
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I believe a standard MX5 seat weighs around 15-18Kg.
I can't see the point in removing the windscreen unless it was a track-only special and a full roll-cage was fitted to put the stiffness back in. I wouldn't want to drive a car like that on the road!

You can remove all carpets, fit lightweight seats & flywheel, remove ac & pas, seat-belts, door panels etc. It starts getting difficult after that.

jay140285

626 posts

191 months

Monday 23rd August 2010
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You can remove the windscreen and it will pass an MOt as long as there are no wipers present.

Wipers = needs a screen for MOT

I looked it to this when I nearly brought a kit car before getting the MX5 Turbo'd.

covmutley

Original Poster:

3,126 posts

197 months

Monday 23rd August 2010
quotequote all
Thanks. I started stripping it over the weekend. Will keep windscreen but undecided on side windows and hood. As said I only really use it on dry days and i'd get wet in a kit car anyway. Enjoyed the first afternoon of the project and it only cost my time! 100kgs reduction seems doable. Someone will probably be along to tell me there is little point in reducing weight but who cares!!

youngsyr

14,742 posts

199 months

Monday 23rd August 2010
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covmutley said:
Thanks. I started stripping it over the weekend. Will keep windscreen but undecided on side windows and hood. As said I only really use it on dry days and i'd get wet in a kit car anyway. Enjoyed the first afternoon of the project and it only cost my time! 100kgs reduction seems doable. Someone will probably be along to tell me there is little point in reducing weight but who cares!!
If you can take 100kgs out of the car then you most certainly will feel the difference in weight, the problem is that doing so tends to compromise the car drastically.

If you're realistic about how you're going to own and use the car, then that's not a problem, but often it seems that people who go down that route haven't fully thought out the consequences.

Ab Shocks

1,686 posts

227 months

Monday 23rd August 2010
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Piers Chandler is doing a run what u brung in the Ma5da race series, if you like I will ask him what you can get away with next weekend at Rockingham

MX-5 Lazza

7,954 posts

226 months

Tuesday 24th August 2010
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A lot of track-day operators insist that you have the side windows up so I wouldn't remove them if I was you. If they are electric then convert to manual but leave them in.

youngsyr

14,742 posts

199 months

Tuesday 24th August 2010
quotequote all
MX-5 Lazza said:
A lot of track-day operators insist that you have the side windows up so I wouldn't remove them if I was you. If they are electric then convert to manual but leave them in.
Obviously the OP would need to check with each track day operator, but I would imagine that if the car was registered as a kit car and hand no windows to put up, then the track day operators would be fine about it.

Plenty of cars on trackdays don't have side windows - Lotus 211, Xbow, Atom etc.

covmutley

Original Poster:

3,126 posts

197 months

Tuesday 24th August 2010
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When I went to the mx5 day at Mallory Park last year the instruction was if you have windows put them up and if you don't, keep your arms inside the car. These issues are well worth checking before parts see ebay or the bin, so thanks.

Been reading lots of threads on mx5nutz. Quite a bit of debate as to whether removing weight is worth it when you can add power via turbo. Having read various opinions my conclusions are that:

-Removing 50kg wil have some impact (laws of gravity), but probably not enough to feel.
-Removing 100kg should have a noticable impact in all areas(braking, turn in, acceleration), but not as much as turbo, or improved driving skills.
-Turbo is probably better than weight loss, giving better performance whislt retaining a certain level of comfort but comes at a price, even if that is quite low compared to the performance increase.
-As someone said above, it depends what you use the car for and the level of comfort you require- mine is not a daily driver.

interesting stuff! Herman your build looks good, any more pics?