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Book/MK chassis's
loggyboy - 17/6/08 at 01:16 PM

Ive recently purchased Chris Gibbs' book to get some ideas for how i want to approach my future build. The chassis in the book has an IRS with custom rear hubs. However I also noted that MK had a lot of input on the design, but my recollection is that the MK kit chassis is DeDion rear axel using adapted donor hubs. Sadly the MK site is down so i cant get all the info on what the MK chassis kits include.

Has anyone had any experiences of both/either chassis to compare both building and handling? Is it worth going for an complete IRS setup?
Im currently weighing up the benfits of a custom chassis over a prebuilt Kit one, but i think i'l end up with a prebuilt one.

It also notes in the book that the whole car weighs in at over 700kgs, which seems alot to me. The whole reason im setting out on this project is i cant get much more weight off my Nova so id like a low centre of gravity car, but i cant see the point in spending all the time and energy on a kit car if i could buy an elise, that might be a few k more, but would be road ready instantly and that weighs in at the roughly the same as the kit.

rayward - 17/6/08 at 01:20 PM

my 2004 MK Indy has IRS, as most do i think

Ray

mookaloid - 17/6/08 at 01:35 PM

If you can't see the point of a kit car compared with an Elise, then buy the Elise.

For many builders, the point is that they have built the car themselves - it happens to be a quick car too.

If you think it's a load of time and energy to build a kit then the chances are you'll lose interest and not get it finished so I would say go and get the Elise then if you want to build a car over a period of time in order to enjoy building something then do that too!

Cheers

mark

Guinness - 17/6/08 at 01:35 PM

My Indy is IRS too! They will do you a dedion back end, but the vast majority of cars they produce are "Indy"pendant.

Mine weighs in at around 450 - 475 kgs, but that is with a bike engine as opposed to a car engine.

You could buy an Elise, but they do have a tiiiny bit of a reputation for biting people on the arse when it all goes wrong. I've seen the results of "Lift Off Oversteer" first hand and it wasn't pretty!

Mike

Mr Whippy - 17/6/08 at 01:50 PM

I don't think you can really compare an Elise with a 7, especially a BEC one, there is a bit more to it than the weight of the car. If you don’t mind forking out the extra cash for an Elise then why not just buy a second hand 7?

Hammerhead - 17/6/08 at 02:10 PM

quote:
Originally posted by Guinness
My Indy is IRS too! They will do you a dedion back end, but the vast majority of cars they produce are "Indy"pendant.

Mine weighs in at around 450 - 475 kgs, but that is with a bike engine as opposed to a car engine.

You could buy an Elise, but they do have a tiiiny bit of a reputation for biting people on the arse when it all goes wrong. I've seen the results of "Lift Off Oversteer" first hand and it wasn't pretty!

Mike


don't lift

MikeR - 17/6/08 at 03:13 PM

quote:
Originally posted by Guinness
My Indy is IRS too! They will do you a dedion back end, but the vast majority of cars they produce are "Indy"pendant.

Mine weighs in at around 450 - 475 kgs, but that is with a bike engine as opposed to a car engine.

Mike


MK did the original book 'live' axle for a while, then upgraded to doing de-dion or live axle. They then brought out their own car which was a little larger and did IRS.

I'm building a live axle / de-dion chassis based on the original sizes (i'm indecisive so keeping my options open).

NSDev has a IRS book sized car (by Stuart Taylor now Aries) which weighs in at 540kg and has a car engine with 200bhp. Its not maxed on out being the lightest car so you could improve it if you wished.

I'm hoping to get my de-dion car in around the same weight, maybe (if i'm lucky) up to 20kg lighter due to a slightly lighter engine and the de-dion being lighter than the IRS setup, although if i come in under 570kg i'll be happy.

chrisg - 17/6/08 at 04:47 PM

The elise weighs 1975lbs without options which is 895kg.

it also has a higher centre of gravity.

Plus people will be forever asking you to book them in for a perm.

cheers

Chris

Dick Axtell - 17/6/08 at 04:47 PM

I'm another one building on the earlier MK chassis - about the same build speed as MikeR !!

My chassis is mainly to the Ron C book version, although I've found that the distance between the inner mountings for the lower wishbones wasn't exactly the same.

Incidentally, MK said at Stoneleigh that they no longer make anything for the Locost version.

loggyboy - 17/6/08 at 04:52 PM

One of the main reasons for wanting to do a locost is to match the compeittion im against in Autosolos, the mods to my nova put me in the low volume/specialist class, meaning 7escs, elises and other road legal kits. I do well against them (considering im in a nova) but not well enough to not get frustrated! Elise is the easy option (and has other bonus, wet weather, slightly easy day to day use etc), but one of the things I liked most about creating the nova was the things ive done that arent just 'bolt on', unique tweaks and mods that make it mine. My comments about 'not seeing the point in spending all the time and energy on a kit car if i could buy an elise', was nothing to do with my lack of commitment to a long term project (the nova took a 8 months and that was 'just' an engine swap), it was more based on the whole point of wanting a lightweight car. I was suprised that the C.G/Haynes car weighed that much, but i think that must have been an odd ball as most quotes of weights for locosts ive seen are sub 600kg. Which is what my aim would be.

loggyboy - 17/6/08 at 04:54 PM

quote:
Originally posted by chrisg
The elise weighs 1975lbs without options which is 895kg.

it also has a higher centre of gravity.

Plus people will be forever asking you to book them in for a perm.

cheers

Chris


I think ur quoting hispec S2s, the S1 111s weighs in at 770kg.

I dont think its that high either TBH, its all FG from the waist (of the car) up.

I dont think elises have that rep so much, maybe untuned/standard ones but that is more reserved for VX220s and mx5s! Most I see look mean. Plus my dad has one so becareful

[Edited on 17/6/08 by loggyboy]

loggyboy - 17/6/08 at 04:56 PM

quote:
Originally posted by Dick Axtell
Incidentally, MK said at Stoneleigh that they no longer make anything for the Locost version.


Explain further please?

StevieB - 17/6/08 at 05:20 PM

quote:
Originally posted by Guinness
My Indy is IRS too! They will do you a dedion back end, but the vast majority of cars they produce are "Indy"pendant.

Mine weighs in at around 450 - 475 kgs, but that is with a bike engine as opposed to a car engine.

You could buy an Elise, but they do have a tiiiny bit of a reputation for biting people on the arse when it all goes wrong. I've seen the results of "Lift Off Oversteer" first hand and it wasn't pretty!

Mike


Though you have to push an elise quite hard to get to that point on the road.

IMO, the Elise probably makes a better road car for long distance blats/touring, and isn't that much slower on the road because it's a bit more poised than a se7en and doesn't skip about as much.

I may change my mind though once my Indy hits the road.

And I believe the standard S2 Elise, without any of the girly options, is slightly lighter and slightly faster than the S1.

[Edited on 17/6/08 by StevieB]

indykid - 17/6/08 at 05:32 PM

quote:
Originally posted by loggyboy
quote:
Originally posted by Dick Axtell
Incidentally, MK said at Stoneleigh that they no longer make anything for the Locost version.


Explain further please?


did you read mikeR's post too?

they stopped making it when they started making the indy. they no longer make bits for it.

tom

James - 17/6/08 at 05:32 PM

quote:
Originally posted by loggyboy
but i think that must have been an odd ball as most quotes of weights for locosts ive seen are sub 600kg. Which is what my aim would be.


That sounds surprisingly heavy for a car essentially not much different to a Locost.

Maybe Chris was sitting in it at the time....

Cheers,
JAmes

Guinness - 17/6/08 at 08:39 PM

quote:
Originally posted by StevieB

Though you have to push an elise quite hard to get to that point on the road.


Yup, he was! Trying to keep up with OiOi.

Mike

StevieB - 17/6/08 at 08:45 PM

That departs from pushing hard and gets into the realms of daftness!

That mus be the incident that led Mike to declare he'd never drive my car when we were talking about doing a car swap at Peebles!

Who was driving the Elise?

procomp - 18/6/08 at 08:21 AM

Hi i have just read the posts again but cant find what COMPETITION discipline the OP is intending to use the car for.

This will make the choice of what chassis desighn is optimal for the discipline easier to workout.

Cheers matt

loggyboy - 18/6/08 at 10:49 AM

Mostly Autosolos, with the likely hood of sprints/hillclimbs at a later date.

I didnt realise that the newer MK chassis were not classed as 'locost' i assumed any 7 based design was a locost if it didnt cost much!

James - 18/6/08 at 04:58 PM

Nah, it's only Locost if it's based on the original Ron Champion design from the Build Your Own Sportscar book.

Most of the sevens have a similarity to the design but it doesnt mean they're Locost of 'Low Cost'!

Cheers,
James

procomp - 19/6/08 at 07:16 AM

Hi in which case you are looking more towards the original book chassis with either a live axle or dedion or irs conversion depending on what takes your fancy.

Reason for this is that all the other manufacturers started making the cars with wider and wider track. MK MNR LUEGO MAC#1. this gave all of them track to wheel base ratios that where out the window especially for small tight circuits.

An other option would be to find an older SYLVIA STRIKER which has a very good track to wheelbase ratio and works well on small tight circuits such as sprint & hillclimb Ect. It's only down side is that it can be a bit twitchy if using on say trackdays / racing with high speed corners due to it's short wheelbase but nothing too drastic.
Or use the original book and re size to become more like the early Westfield with the shorter wheellbace which was about as good as it gets as a compromise on the track to wheelbase ratios for circuit and sprint & hillclimb's.

HTH cheers Matt

britishtrident - 20/6/08 at 12:13 PM

One of the most important differences between the Indy and the book Locost was the 1" difference in chassis depth, the book chassis is really short on space in the footwells.

britishtrident - 20/6/08 at 12:18 PM

quote:
Originally posted by Hammerhead
quote:
Originally posted by Guinness
My Indy is IRS too! They will do you a dedion back end, but the vast majority of cars they produce are "Indy"pendant.

Mine weighs in at around 450 - 475 kgs, but that is with a bike engine as opposed to a car engine.

You could buy an Elise, but they do have a tiiiny bit of a reputation for biting people on the arse when it all goes wrong. I've seen the results of "Lift Off Oversteer" first hand and it wasn't pretty!

Mike


don't lift


Most drivers these days don't know how to drive a RWD never mind a mid/rear engined short wheel base RWD.

Remember when the early Suzuki Jeeps were give a dark reptation for bad handling.

clockwork - 20/6/08 at 12:41 PM

Had an elise, loved it... building a locost because if you bend an elise chassis it is game over.
I had a "lift off" (actually changing camber) moment and got away with a bent alloy and snapped tie rod. Sold it 2 months later to build locost.

austin man - 21/6/08 at 07:24 PM

It was
Martin Keenan who had input into the new Haynes roadster not MK. MK do IRS and have their own rear uprights and wishbone on the Indy and the new spec indy