Design Your NEW SEVEN
Discussion
I think that most Kit manufacturers are looking for the next Seven design concept, and with the dwindling supply of suitable rear wheel drive donors, the only alternative solution i see is a mid-engine Fwd. setup.
A few have moved in this new niche, Sylva being the first in this market, and others are catching on , with more modern kits planned for the future.
I have an old sketch of mine, based on the Sylva Mojo chassis, but could be updated with a modern and slightly longer and wider chassis.
What do you envision as your modern seven?, what design would best suit it? and any thoughts on future trends..
Just to start the discussions, here is my old sketch...
OK, my take on it - make it a bit longer in the rear and possibly a bit narrower for accepting the longitudinal FWD Saab 99/900 drivetrain and front suspension.
The biggest advantage:
No suspension pick up points and structural elements needed outside the chassis perimeter, simple bolt-on of donor car wishbones.
The second biggest advantage:
Wholesale adaptation of OE unequal length double wishbone set up from relatively cheap and widely available donor car. Full adaptability of camber and castor settings as well as toe-in/out.
More advantages:
Compact drivetrain arrangement, longitudinal configuration with weight centred near the axle and equal length driveshafts.
Upmarket OE engineering vs. Ford et al, at scrapyard prices.
Bulletproof engine, lots of possible power options, OE turbo applications giving good power/weight and torque/weight ratios
Lots of aftermarket power options for turbo engines (remember the Scandinavians used to rallycross these puppies to great effect!).
Disadvantages:
Iron block engine, so actual weight of engine could be a performance issue in a very lightweight application. Not so important at/near Locost level, IMO - you're hardly going to build it with carbon fibre everything...
CoG could be lower - engine sits on top of gearbox, it's 45 deg slanted and not very tall, though...
Steering rack of donor car could be used, but apart from that you're on your own at the front end of things.
The biggest advantage:
No suspension pick up points and structural elements needed outside the chassis perimeter, simple bolt-on of donor car wishbones.
The second biggest advantage:
Wholesale adaptation of OE unequal length double wishbone set up from relatively cheap and widely available donor car. Full adaptability of camber and castor settings as well as toe-in/out.
More advantages:
Compact drivetrain arrangement, longitudinal configuration with weight centred near the axle and equal length driveshafts.
Upmarket OE engineering vs. Ford et al, at scrapyard prices.
Bulletproof engine, lots of possible power options, OE turbo applications giving good power/weight and torque/weight ratios
Lots of aftermarket power options for turbo engines (remember the Scandinavians used to rallycross these puppies to great effect!).
Disadvantages:
Iron block engine, so actual weight of engine could be a performance issue in a very lightweight application. Not so important at/near Locost level, IMO - you're hardly going to build it with carbon fibre everything...
CoG could be lower - engine sits on top of gearbox, it's 45 deg slanted and not very tall, though...
Steering rack of donor car could be used, but apart from that you're on your own at the front end of things.
Edited by 900T-R on Thursday 22 February 10:39
mafioso said:
I'm sorry but FWD is not going to really bring in the kit car wannabes is it!? As for the struggling numbers of donor cars, Westfield have starting using the MX-5 as a donor car! There are bloody thousands around!!
Good point...
That is a very good sportscar to consider, and works perfectly for a seven setup, but you have millions of fwd scrap engines out there, cheaper than an mx5, waiting for a mid-engine chassis.....
I think it all boils down to, how much you want the kit to cost, and the best balance between engine availability and parts, manufacturing costs, and build costs for the kit enthusiasts.
fuoriserie said:
Good point...
That is a very good sportscar to consider, and works perfectly for a seven setup, but you have millions of fwd scrap engines out there, cheaper than an mx5, waiting for a mid-engine chassis.....
The problem with the MX-5 route is this: the MX-5is a sports car. A very good one at that, so it'll always have a bit of desirability. Even if I have a very rusty one that could only be saved with a re-shell, do I drop a couple of grand on it in sourcing a good shell and transferring the oily bits, or do I spend a few thousand more on a kit to recreate pretty much what I have, only looking arguably well, 'home built' inside & out?
900T-R said:
[quote=fuoriserie]
. A very good one at that, so it'll always have a bit of desirability. Even if I have a very rusty one that could only be saved with a re-shell, do I drop a couple of grand on it in sourcing a good shell and transferring the oily bits, or do I spend a few thousand more on a kit to recreate pretty much what I have, only looking arguably well, 'home built' inside & out?
. A very good one at that, so it'll always have a bit of desirability. Even if I have a very rusty one that could only be saved with a re-shell, do I drop a couple of grand on it in sourcing a good shell and transferring the oily bits, or do I spend a few thousand more on a kit to recreate pretty much what I have, only looking arguably well, 'home built' inside & out?
Personally, I would rebody an mx5....., that is why I'm considering a different alternative engine solution.
900T-R said:
mafioso said:
I'm sorry but FWD is not going to really bring in the kit car wannabes is it!?
Ehm, you miss the point. FWD drivetrain moved to the back end = instant mid-engined RWD config...
Ah so it won't actually be FWD then! Right I see! Well yes now I see that mid engine from FWD cars is fine! Heck, they do it in the elise as well as others!!
The FWD front to rear conversion problems seem to suffer from the fact that the FWD donor has generally been engineered to get as much mass behind the front wheels as possible. When you move this to the rear you end up with a very tail heavy car with al the wait high up giving you a real roll oversteer and lift off oversteer potential. I reckon this rules out a lot of the more mainstream options. You need to find a FWD manufacturer who stuck the engine out the front with the same disdain for physics as Porsche in sticking it 'out the back'. Audi springs to mind. You can then use what makes their cars dire and understeery to make yours beautifully balanced and nimble. I would also like to work something around the front end of the Mazda 323F. It's a lovely little engine, well engineered and revs really nicely. All ally and I reckon the donors should now be reasonably cheap.
Looks fantastic! I'm really tempted to do something like this, (with the designers permission of course) but in my experience it can cost up to £100k to fully develop and then tool up for a new kit car and therefore the decison to go ahead would have to be based on potential sales. My question is,
WOULD YOU BUY ONE IF IT WERE AVAILABLE AND WHAT DO YOU THINK IT SHOULD COST?
My only design concerns at this stage would be 4k for screen tooling cost unless it could be made to use an off the shelf unit. My R3 uses an MX5 screen and they cost me just over a ton plus VAT. The Lancia Stratos screen looks similar to sketch but I feel it maybe too wide and they are £400 ish. Any suggestions on screen to the stylist with dimensions may take it a step further. My full screen option for the Rocket is VW and costs less than £100 plus frame. I believe it needs to fall into the Locost category. My other concern is head light position as the illuminated area has to be within 400mm of the edge of the cars footprint. In full lock on my new Rocket chassis the tyres have 60mm clearance from the chassis rails so I suspect the lights on the sketch will need to bulge out from the body line which is very unfortunate. Please please post your comments as I or another manufacturer watching this discussion may be persuaded to take the plunge. Your opinions are greatly valued, please bear in mind that typical low volume sales are unlikely to make a good business case so I don't think anyone need be overly worried about any manufacturer using your ideas and making a fortune. IF YOU WANT TO MAKE A SMALL FORTUNE OUT OF KIT CARS THEN JUST INVEST A LARGE FORTUNE ! Your views may convince someone to invest though Kind regards Stig Mills
WOULD YOU BUY ONE IF IT WERE AVAILABLE AND WHAT DO YOU THINK IT SHOULD COST?
My only design concerns at this stage would be 4k for screen tooling cost unless it could be made to use an off the shelf unit. My R3 uses an MX5 screen and they cost me just over a ton plus VAT. The Lancia Stratos screen looks similar to sketch but I feel it maybe too wide and they are £400 ish. Any suggestions on screen to the stylist with dimensions may take it a step further. My full screen option for the Rocket is VW and costs less than £100 plus frame. I believe it needs to fall into the Locost category. My other concern is head light position as the illuminated area has to be within 400mm of the edge of the cars footprint. In full lock on my new Rocket chassis the tyres have 60mm clearance from the chassis rails so I suspect the lights on the sketch will need to bulge out from the body line which is very unfortunate. Please please post your comments as I or another manufacturer watching this discussion may be persuaded to take the plunge. Your opinions are greatly valued, please bear in mind that typical low volume sales are unlikely to make a good business case so I don't think anyone need be overly worried about any manufacturer using your ideas and making a fortune. IF YOU WANT TO MAKE A SMALL FORTUNE OUT OF KIT CARS THEN JUST INVEST A LARGE FORTUNE ! Your views may convince someone to invest though Kind regards Stig Mills
fuoriserie said:
What do you envision as your modern seven?, what design would best suit it? and any thoughts on future trends..
I like your idea and I like the Sylva designs (I have a striker) but something like your image is not a modern 7, to me a modern seven is already in existence, it is the 7 body shape with modern running gear and drivetrain, anything else isn't a 7 IMO.
Totally agree with the comments above. As a manufacturer who has just entered the kit market the costs can be pretty scary to get a car into a production ready format so you have to be completely convinced that the market is there before taking the plunge.
Currently I believe this means coming out with something new and fresh as there are already so many companies competing in the 7 and Cobra scenes.
We too have been looking into what we think could be the way to go with a 'budget' offering as our current car is obviously a fairly high end product in the kit market, and it is difficult to forsee where to take the cheaper alternatives as the mainstream sportscars such as the Elise are now so affordable (certainly equivalent in price to a realistic build budget for a reasonable 7 type car, ie 7.5-10k).
As Mr Mills has said, we as manufacturers love to follow these kind of threads as they provide the proving ground of where market opportunities may open up, let us know what you like and you may well end up seeing it!
Look forward to seeing and reading lots more.
Neil.
Currently I believe this means coming out with something new and fresh as there are already so many companies competing in the 7 and Cobra scenes.
We too have been looking into what we think could be the way to go with a 'budget' offering as our current car is obviously a fairly high end product in the kit market, and it is difficult to forsee where to take the cheaper alternatives as the mainstream sportscars such as the Elise are now so affordable (certainly equivalent in price to a realistic build budget for a reasonable 7 type car, ie 7.5-10k).
As Mr Mills has said, we as manufacturers love to follow these kind of threads as they provide the proving ground of where market opportunities may open up, let us know what you like and you may well end up seeing it!
Look forward to seeing and reading lots more.
Neil.
Corpulent Tosser said:
fuoriserie said:
What do you envision as your modern seven?, what design would best suit it? and any thoughts on future trends..
I like your idea and I like the Sylva designs (I have a striker) but something like your image is not a modern 7, to me a modern seven is already in existence, it is the 7 body shape with modern running gear and drivetrain, anything else isn't a 7 IMO.
I think you need to see this in a more philosophical way than that - this tread more or less is an offshoot of the one about the new version of Haynes Locost build book, which now is based on using a Sierra as a donor car. We concluded that cheap mainstream RWD donors are getting very scarce, and a 21st century fast-froward from the days when everyone and their dog would build specials from Ford 1172cc sidevalve engines et al, would be a mid engined kit car based on FWD mechanicals.
Edited by 900T-R on Thursday 22 February 13:44
stig mills said:
My only design concerns at this stage would be 4k for screen tooling cost unless it could be made to use an off the shelf unit.
Have you spoken to Taraglass in aus about screens? This was a concern for me on my car (and it may still end up as a off the shelf unit) but Taraglass seem to be able to make screens for less than I can buy off the shelf units!
Davi said:
[quote=stig mills]My only design concerns at this stage would be 4k for screen tooling cost unless it could be made to use an off the shelf unit.
Have you spoken to Taraglass in aus about screens? This was a concern for me on my car (and it may still end up as a off the shelf unit) but Taraglass seem to be able to make screens for less than I can buy off the shelf units!
Thanx for that, I hadn't heard of them but I suspect as I only order in tens that transport will be heavy from Aus. My R3 uses an MX6, not MX5 as quoted.
I've also just noticed that the original sketch we are refering to was based on a Lancia screen. Anyone that can sell them for £100ish would get an order.
Kind regards Stig Mills
mafioso said:
I'm sorry but FWD is not going to really bring in the kit car wannabes is it!? As for the struggling numbers of donor cars, Westfield have starting using the MX-5 as a donor car! There are bloody thousands around!!
Why not?
Most of today's drivers only drive FWD and a FWD car can be made to handle very well.
The weight distribution becomes less of a problem.
The only issue is it being fitted transversely (as donor), restricting the design options somewhat.
The biggest advantage is how easy the build would be. The easier the built the more it would attract first time builders, builders that would then move on to bigger & better things.
stig mills said:
Davi said:
stig mills said:
My only design concerns at this stage would be 4k for screen tooling cost unless it could be made to use an off the shelf unit.
Have you spoken to Taraglass in aus about screens? This was a concern for me on my car (and it may still end up as a off the shelf unit) but Taraglass seem to be able to make screens for less than I can buy off the shelf units!
Thanx for that, I hadn't heard of them but I suspect as I only order in tens that transport will be heavy from Aus. My R3 uses an MX6, not MX5 as quoted.
I've also just noticed that the original sketch we are refering to was based on a Lancia screen. Anyone that can sell them for £100ish would get an order.
Kind regards Stig Mills
Worth chatting to them - I'd only be ordering 2 - there are ways and means of getting the shipping costs down
Still looks good,
Must also say I think the old MGF is a pretty good rear wheel drive Donor, plenty of front end crunched ones cropping up and now head gasket failures are beginning to right off old ones.
We are using a lot of the MGF in our project, and still getting an overall car weight of under 600 kgs, so far we have recycled the Engine, Box, Shafts, ECU's, instrument binnacle, handbrake, gearlever and cables, wiring loom.
Keep up the good work
Joe
Must also say I think the old MGF is a pretty good rear wheel drive Donor, plenty of front end crunched ones cropping up and now head gasket failures are beginning to right off old ones.
We are using a lot of the MGF in our project, and still getting an overall car weight of under 600 kgs, so far we have recycled the Engine, Box, Shafts, ECU's, instrument binnacle, handbrake, gearlever and cables, wiring loom.
Keep up the good work
Joe
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