LocostUSA.com

Learning how to build Lotus Seven replicas...together!
It is currently May 21, 2024, 9:59 pm

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 394 posts ]  Go to page 1, 2, 3, 4, 5 ... 27  Next

Which Engine ?
Suzuki G10 3 cylinder engine 26%  26%  [ 7 ]
600CC 4 Stroke Production Motorcycle Engine 67%  67%  [ 18 ]
Toyota AFE 7%  7%  [ 2 ]
Total votes : 27
Author Message
PostPosted: February 9, 2009, 10:30 pm 
Offline
User avatar

Joined: October 15, 2006, 11:15 am
Posts: 942
Hi Guys,

I've decided to splitt up from the previous post since I think it would be more constructive to be all on the same direction.

This tread is to discuss creating a North American version of the Formula 750 from the 750 motor club in the UK.

You can find out more about the class here: http://www.750mc.co.uk/F-750-formula.php
The F. 750 rules are here: http://www.750mc.co.uk/images/uploaded/2009%20Regs%20-%20750%20Formula.pdf
and here is there forum: http://www.750formula.co.uk/forum/

What we all agreed was that the engine would be a spec engine and it would be the 993cc 3 cylinder engine found in the Geo Metro and Suzuki Swift.

Here is the very basics
Spec Engine: Geo/Metro 3 Cylinders of 1.0L capacity...
Tranmission: 4-5 speed RWD transmission from any production car, cannot be sequential, No Transaxles
Differential: Can either in the form of a solid axle or from an IRS car. Must be from a production car. No LSD.
Chassis: Tubular steel spaceframe, can be pannelled with rivited and/or bonded aluminium of a maximum thinckness of 14 gauge. Honeycomb, kevlar or carbon fiber materials are prohebited as structural component of the chassis.

Kevlar, or carbon fiber can be used in non structural applications



In order to adapt the rules for here, we will need to adapt them the the GCR of the SCCA, NASA and ASN Canada FIA. these changes will be on the safety aspects. Rollcage requirements will be the same as those for sports racers. Personal safety requirements will be the same.

As for the weight of the car at first I tought of 900lbs including driver, but that was optimistic. I have since then thought of 993 lbs i.e. the same number as the engine capacity, also if you guys like the idea I would call this class Formula 993. This is not set in stone so lets discuss the minimum weight and name.

B85, wheel size was free. As for tire size I was thinking 8 inch maximum width. We are using full race slicks. When I look at the hoosier spec 8 inch wide tires are only available in 13 inch wheels, but there is a 5.5 inch wide slick in the 15 inch wheel diameter. If someone want to use tose tire then he could take 15 inch wheels. It's a builders decision.

Is everybody ok with race slicks or the size ?

DeanD3W: The UK rules state an open diff. With only 65HP at the most and 8 inch slicks wheelspin might not be such an issue, but it could.

We need to discuss the diff. Now one reason for open diff, is that most cars are equiped with open diff, so there would be an added cost if we allow them. also we would eliminate some available components if no suitable locking or LSD are not available for them.

Yes I'm building a car. I'm putting my money were my mouth is :twisted:
I'm gonna start doing some lobbying among a few buddies of mine to convert them to this :mrgreen:

Cheers,

Fred


Top
 Profile  
Reply with quote  
PostPosted: February 9, 2009, 11:37 pm 
Offline
User avatar

Joined: January 13, 2008, 9:07 pm
Posts: 1444
Location: Glendale AZ
The Goodyear looks to be the 20x8=13?
Rim looks to be a 6"?

_________________
American 7 5.0 T5
Lotus 15 ish?
914/H6


Top
 Profile  
Reply with quote  
PostPosted: February 9, 2009, 11:46 pm 
Offline

Joined: December 29, 2007, 10:41 pm
Posts: 1008
Location: Vancouver, BC
Fred,
This should be very interesting. I've been interested in the 750 formula for a long time (11 years now) and have had the idea to build one, but seeing as there wasnt any real interest here in NA i never thought it would happen. But, this has given me some much needed support.

It would be great to get a bunch of cars constructed and get the amateur back in to "special" building as they did back in the 50's right through to the 70's when things started getting a little more expensive and more advanced.

I look forward to any input towards the rules and hope that this does indeed take off.

Cheers,
Rod


Top
 Profile  
Reply with quote  
PostPosted: February 10, 2009, 12:16 am 
Offline
User avatar

Joined: October 15, 2006, 11:15 am
Posts: 942
B85: Your right the 8 inch wide slicks are cantilever slick if I remember right, that's why the suggested rim size is 6 inches, the 7.5 inch wide are not and can be mounted on rims up to 8 inches. You therefore have a choice there, which is kinda cool since both sizes have advantages and drawbacks... You could also run 10 inches wheels. It's up to you rthe designer to make the decision.

cs3tcr: I've been a fan of the formula since I got the book , I had given up on it since I tought I was the only nutcase. I found out in the other tread that I wasn't pfffew.

I think it's just a question of building several cars, showing up, creating and maintaining the interest. They are momentum cars and will be slow in the straights. But that's part of the lowcost factor, being light, they will be easy on the tires and brakes, plus keeping the engine fairly stock should not be a strain on components i.e. transmission, driveshaft, axles and diff. This is the key in the low budget of the class.

I'm hoping of finishing and running my car for the Summer of 2010, I intend on doing a few shows, plus some SoloSprints, Lapping and hopefully a race or two.

I'm going true the GCR this week so I should have the safety requirements down. I still want to run the basics with the pioners i.e you guys, since you'll be building cars also.

Cheers,

Fred


Top
 Profile  
Reply with quote  
PostPosted: February 10, 2009, 11:12 am 
Offline

Joined: October 8, 2008, 12:22 pm
Posts: 199
Location: Austin Texas
I hope via this forum we can get about 10 cars under construction. I never thought I would be so excited about a 65 hp car!

I think either Formula 993 or 993 Formula would be good names. We're following the 750 Formula tradition as they're named after the displacement of their first engine. "750 Formula" is said backwards compared to convention, but that is their tradition... Formula 993 rolls of my tongue better, but I would like acknowledging tradition with "993 Formula". Which ever way this goes, I'm happy.

Since smaller drivers will still have the advantage of the low cg their ballast plates provide, vs us heavier guys, with all the weight distributed higher, I like 993 lb as a with-driver weight limit too. Maybe I should have an arm amputated, to lower my cg :D

750 Formula specifies that tires are free, but if slicks are used, they must be Yokohama 160/515-13. 160 mm is 6.3", so we'll allow wider slicks than 750 Formula if we go with 8" as the limit. If the 750 Formula tire (tyre :) ) spec is practical here then my slight preference is to adopt the same.

Jawfish - You brought up a good point about the losses associated with the CV joints in half-shafts - I may choose a solid rear end for my car.

I hope I can keep pace with the group on the build. I have five kids, ages 10 and under & spend a weekend a month and two weeks each year with the Coast Guard Reserve, so time isn't always easy to find. My primary employment is shifting soon to a situation that should provide the time I want for this. I'm also determined to do this. Over the past 10 years I haven't done much with cars, but I put about 1400 hours into a FSAE car in 1995, so I understand the "cubic hours" concept of car building.

The initial cars should be owner fabricated and built, but I wonder if in about five years we will want to require that each car be owner built/assembled, but allow some in the group to sell two or three frames per year... We must not let costs increase (Stohr-ation), but we may want to include those who are willing to build/assemble their car, but don't feel up to the fabrication skills needed - we will be interested in gaining numbers after the initial cars are built & 750 Formula apparently allows purchased frames and body parts, according to what I see at http://www.racekits.co.uk/750_formula.htm. It's too early for us to go there now, but what do you think of allowing this beginning in say 2015? We can cross that bridge later. If we can make this work as a truly owner built series that would be better. Maybe those who don't want to fabricate can buy used cars... Maybe we should then have a rule that no one can run a used car unless they first fully dis-assemble & re-assemble the car, with some pictures to prove they were present for the work..? I would not participate if this were to become a claimer class, but maybe there should be a rules committee determined maximum selling price for a used car as another anti-Stohr-ation measure.

I don't suppose anyone has a spare 750 Formula book that they'd be interested in selling? :wink: I'll be looking for one, just for background info.


Top
 Profile  
Reply with quote  
PostPosted: February 10, 2009, 12:42 pm 
Offline
User avatar

Joined: January 13, 2008, 9:07 pm
Posts: 1444
Location: Glendale AZ
The book is on Amazon. $240.00!!!!! Used? Goog condition?
Maybe someone could scan it and post the good stuff?

_________________
American 7 5.0 T5
Lotus 15 ish?
914/H6


Top
 Profile  
Reply with quote  
PostPosted: February 10, 2009, 12:54 pm 
Offline
User avatar

Joined: January 13, 2008, 9:07 pm
Posts: 1444
Location: Glendale AZ
Also what about the Carb? Size? Manifold?
Will we have some one cast sum up?

_________________
American 7 5.0 T5
Lotus 15 ish?
914/H6


Top
 Profile  
Reply with quote  
PostPosted: February 10, 2009, 1:26 pm 
Offline
User avatar

Joined: October 15, 2006, 11:15 am
Posts: 942
I think many of us will choose the solid axle… I’m trying to locate one, since it’s what I want to run. Easier to build, less chances of messing things up and less power loss.

One thing that I think we don’t want is to have Stohr ruin our amateur Designer aspirations…I think this is a pretty good compliment to Lee Stohr. On the other hand, we do want this to grow and for some a shortcut might be what will get people in the fun. I think we have to allow some of us to sell components or kits, but not new complete turnkey cars. We also have to allow the selling of used cars. This will again help people get in and encourage actual competitors to build new cars.

I love the Racekit frame and components. With his frame you can put your own suspension and a pre built kit… This is great for the guy who doesn’t want to build a frame. What we need is a customer car rule… Something along the lines that components/kits must be bought from existing competitors. Or simply from an approve list of car builders. We need to have also something requiring new cars to be assembled by their owners.

Tires: Some had express the desire to have a wider tire than the 6 inch slicks, for a greater cornering speed. There are 6 inch wide slick available. I’d like to see the option of an 8 inch slick remain, it give more freedom. I know I’m looking at running 6 inch tire up front, at the back I’m not sure if 8 inch are what I want… What do you guys think?

Engine: I’ve been looking around. Stock horsepower was 48-55 HP, I’m not sure that a free exhaust and free intake with a carb will get us at 65HP. Are we ok with that?
Also the intake is on the right and the exhaust on the left. This means in our N.A. driving positions the header will be on the wrong side for the front engine cars. It’s not such a big deal for me but what about you guys?

Intake manifold: The 750 rules make them free, carb choice also, the only requirement is that it is a single choke carb. Are we ok with that ?
I'm thinking of welding one up out of aluminium. I've seen webers being used, only 1/2 of it is being fed into the intake, the other half is doing nothing, hence within regulation.

Lubrification: I hope everyone have noticed that lubrification is free. So for those what want to experiment on Dry Sump you will be free to do so. Billzilla dry sump sytem exlanation is worth taking a look. Are we ok with that ?

Name: I agree Formula 993 sound better than 993 formula, what do you think?

Dean: … just do it… I think will find a way of motivating each other. Some cars will be built on a longer period and that’s OK, you’ll be living the dream. Hey it’s taken me more than 3 years to build my Locost… The simple reason was I got distracted. I built another locost, built a Solo 2 EPrepared Civic, and two roll cages. Today I only work on my projects.

I'm not to keen on scanning a book and posting it on the internet. It a major setback that the book is no longuer available. I guess we need to come up with more than just a set of rules, but also a builders ressources in order to compensate. The best would be a Class webpage with a Garage section where various builds could be showcased, Rules posted, Technical ressources section and so forth. I have the space on my website to do so... but first thing first, the name, the rules...

Cheers,

Fred


Top
 Profile  
Reply with quote  
PostPosted: February 10, 2009, 1:55 pm 
Offline

Joined: December 29, 2007, 10:41 pm
Posts: 1008
Location: Vancouver, BC
Fred,
Was thinking about all the crap i have in my personal inventory and i forgot that i had a spare Nash Metro rear axle, an MG Midget rear axle and a Morris Minor rear axle. Plus a number of Spit front uprights and a full set of coil overs. Looks like all i'm in need of at the moment is time, motor and a gearbox.

As far as the header being on the left side, whats the problem? Most race cars are RHD so it shouldnt pose a problem, should it?

On the carbs, one choke should be fine. Size shouldnt be restricted due to the stock nature of the motor.

The name sounds great, engine size and weight both tied into the name.

Onto the build site etc, should we get in touch with the UK group to see if they are keen on taking this idea on board with them? Try to tie the NA stuff into the UK stuff?


Cheers,
Rod


Top
 Profile  
Reply with quote  
PostPosted: February 10, 2009, 2:02 pm 
Offline
User avatar

Joined: October 15, 2006, 11:15 am
Posts: 942
For the headers, you could have the pipe going over your legs, if the engine is setback. I'll just insulate my car for it..

Hey that's a lot more parts than I have lying around :shock: Looking forward to seing your build. I guess once the 11 is done you'll jump right into it. I've gotta take an inventory of what I have. Plus I've got enought 1*1 inch tubing left to do a frame or two.

I love the idea of grafting to the 750F forum. That would be amazing. Yhea we need to get in touch with them.

Fred


Top
 Profile  
Reply with quote  
PostPosted: February 10, 2009, 2:17 pm 
Offline

Joined: October 8, 2008, 12:22 pm
Posts: 199
Location: Austin Texas
Maybe if we contact the publisher, they will be willing to print a few (~20) new copies of the book? If not, maybe they'll be willing to send an email giving permission to copy the book for the specific number of us currently participating, on a one time only basis..? At least one of us has a book, I believe. What do you think?

I'm fine with an 8" tire width limit. 8" wide slicks and wings - all with ~60 hp :lol: Cool!

I'd be fine if we allow EFI. If no head modifications are allowed then I think we'll be fine. Of course if one chooses EFI then their wiring and fuel system will be more complex. I'm OK though if carburetors are required... Why not just let carburetors be free/unrestricted? Is there a reason we need to adhere to the single choke requirement? If we're less restictive that leads to a bit more power out of our Metro engines... It seems like our stock heads will act as a sufficient equivalent of a restrictor plate. Should we require no slides, as I believe 750 formula does?


Top
 Profile  
Reply with quote  
PostPosted: February 10, 2009, 2:44 pm 
Offline

Joined: December 29, 2007, 10:41 pm
Posts: 1008
Location: Vancouver, BC
Fred,
I do have to finish the Eleven by July, but seeing as i only get one day a week to work on it, i have lots of time to fool around with CAD drawings for the "new" project. I've already got some idea's floating around.

Dean,
I think going with carbs rather than EFI will make things a little less complicated and a little cheaper. In terms of making the carbs free, its not such a bad idea, but it all depends on how well the motor responds to a header and a single carb. Should the single car not provide enough power, then i think we, as a group, should look at possibly allowing two chokes (as in a single DCOE) or a pair (as in a half set) of bike carbs, seeing as bike carbs are a whole lot cheaper than a Weber and provide a more interesting set up in my mind.

I was looking through Staniforths Race and Rally book, and he has a couple stories on some of the 750 cars and they seemed to average about 65 hp from the Reliant motor. So, if we can make about that with a stock Metro engine, then great.

Cheers,
Rod


Top
 Profile  
Reply with quote  
PostPosted: February 10, 2009, 4:54 pm 
Offline
User avatar

Joined: October 15, 2006, 11:15 am
Posts: 942
In my case I only get to work on my projects on the weekends, this is going to give me time to design the car first. The Locost should be finish by the end of the spring :D

I’ve already got the basic dimensions of the chassis jotted down. I’m basing my design on the Racekits chassis. I forgot about the Race and Rally book I need to have a look at it tonight. The rear suspension will be a 4 link design, most likely with a mumford. This time having a narrow chassis I will be able to do it properly i.e. long links. Up front I’m still planning to use the the mini uprights

For those of you without the book, they use ¾ by 18 gauge ERW for the front suspension arms.Yup keep it light baby !!!

When possible I’d like to stay close to the 750F rules, but as for the carb I’d be ok with allowing twin choke carbs. From the build logs in the 750 forum most use Webers, but only connect half . I still would rather not see EFI.

Fred


Top
 Profile  
Reply with quote  
PostPosted: February 10, 2009, 5:01 pm 
Offline
The voice of reason
User avatar

Joined: January 10, 2008, 4:47 pm
Posts: 7652
Location: Massachusetts
Carbs free sounds like a good idea. I think you guys need to get whatever power you can out of the stock motor. FI involves high pressure fuel and can be a risk in an accident, also programming and electric system requirements. The manifold for 3 bike carbs would be simple and single carbs per cylinder would allow tuning. Other setups seem relatively painful, except for the stock carb.

_________________
Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.


Top
 Profile  
Reply with quote  
PostPosted: February 10, 2009, 5:06 pm 
Offline

Joined: October 8, 2008, 12:22 pm
Posts: 199
Location: Austin Texas
Fred, Rod, and I hope others,
I'm OK with a carburetor if most prefer to go that route, but I think we should think about EFI for a while... Even dirt bikes are beginning to use EFI now... It won't be long and carburetors will only be for the "old guys". With all other things being equal a well tuned carburetor vs well tuned EFI should perform about the same. Especially since we're a bit concerned about whether our engine choice might be a bit shy of the power we would like, it seems reasonable to build some cars with free induction system choice (but always a dead stock head) and see where we are.

I think I might prefer to try EFI... I should be able to use some of the stock system (if the engine I buy is EFI equipped), so it may be just about as easy as a carburetor in some respects.

This affects the fuel cell I need to buy, but mostly just the details associated with its plumbing. What fuel tank, size, location, and type are typically used in 750 formula? I'm currently thinking of the location just behind a well reclined driver's seat. Running the car in some enduros would be a lot of fun - that would push me towards a larger tank/cell, but our typical racing would be 30 minutes or less, so I expect most cars in the UK have small tanks.

I'm not sure if I'll use RHD or LHD - either way the Metro exhaust being on the left shouldn't bother me... I'm picturing the engine layed down a bit, so that should make exhaust routing easier (but a carburetor more difficult, now that I think about it - maybe I should choose RHD).


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 394 posts ]  Go to page 1, 2, 3, 4, 5 ... 27  Next

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
POWERED_BY