From reading the rules, Dwarf cars are legal in F-mod class. And reading the rules for Dwarf, you can basically build a 1200 lbs car with a 1000+cc bike motor, and there is no specs or limit on suspension. So, in theory you could build a bike motor locost wrapped in a model A looking body (with roof) and have a blast. It also seems like it would be faster than the F500’s that dominate FM. Why haven’t I seen this before. What am I missing?
How do the people running stock Legends cars do? Has anyone seriously run one of those as an initial satay point. I know I’ve heard of them running both NASA (road racing and time trials) and I’ve seen photos of them running autocross.
Very interesting Q BTW.
From what I’ve read Legand cars are a different situation, because they are a spec class with very defined limits. They have the engine, suspension, diff, body all defined in the rules. The Dwarf rules, as defined for FM, are relatively open. They define the weight, dimensions/wb, and a bunch of bike engines up to 1200cc. It seems like there are a bunch of options within those rules.
Because f500 is 800lbs (with driver) with 100ish HP through a cvt, meaning that a peaky bike motor making more power isn't as effective, the cvt is always on song.
Plus I think dwarf is more limited than you think, but haven't researched that much.
Did some looking, requires automotive rear end (quick-change allowed). Metal bodies, 65 inch track (to f500 55inches). Motors are actually pretty limited.
Yeah I thought you had to pass the rules of the dwarf classes to be eligible for fmod. Otherwise it's amod.
But it's been a while since a detailed reading has been done by me.
Also, the microvan at the challenge is essentially a dwarf car. If they could get the engine to run reliably it would be really fast I think.
Robbie said:Yeah I thought you had to pass the rules of the dwarf classes to be eligible for fmod. Otherwise it's amod.
But it's been a while since a detailed reading has been done by me.
Correct, has to meet western dwarf rules per Scca with a few "don't worry about that's"
I think what you are missing is understanding of how fast FM is... in pax terms they are only outpaced by AM, BM, KM (karts), and FSAE. DM locosts are slower by a good margin.
There were a few guys running Legends cars as road racers at Waterford Hills 15 years ago. After awhile the cars started developing frame cracks. They were designed for a spec BFG street tire and the Hoosiers stuck so well the extra stress was breaking the chassis. That may or may not be an issue in autocross.
There is a guy who auto crosses his locally. Usually beats our Normal FTD guy by 2 seconds or so.
Comparing DM and FM rules, it looks like a Dwarf car only loses 30 lbs compared to DM (1280 vs 1250) and can only run 10” wide tires. So, it seems like the Dwarf cars don’t have a chance.
As partially stated above, because F500's are faster.
the narrow width, extremely low CG, and CVT's offering peak power all the time mean they're very hard to be faster than.
spacecadet said:As partially stated above, because F500's are faster.
the narrow width, extremely low CG, and CVT's offering peak power all the time mean they're very hard to be faster than.
There's a good excuse for a thread there. I never think of CVTs as being a performance item, but that's what snowmobiles use also, isn't it? How come we don't see more of that sort of thing in car applications?
CVT’s are pretty much the main transmission used in small cars now. As I understand they can’t take the high torque requirements for larger vehicles (yet?).
And CVT’s dominate in FM and most of the AM cars in auto cross for the reasons stated above.
In reply to Nate90LX :
I'd think that they'd be a good match with BEC Locosts. Hmmm might have to start checking the Snowmobile ads.
Kreb said:spacecadet said:As partially stated above, because F500's are faster.
the narrow width, extremely low CG, and CVT's offering peak power all the time mean they're very hard to be faster than.There's a good excuse for a thread there. I never think of CVTs as being a performance item, but that's what snowmobiles use also, isn't it? How come we don't see more of that sort of thing in car applications?
Well, snowmobile racing is closely related to drag racing, and in drag racing there isn't a stigma against the automatic trans...
My guess is that a large factor is that sports car buyers don't buy cvts, and that's why they aren't in sports cars. Heck, in our world, often the faster transmissions (dual clutch, etc) are still shunned because "no third pedal".
I do find it odd that snowmobiles use cvts and motorcycles use manuals however. Maybe the range has something to do with it? (Ie motorcycle top end 2x the top end of a snowmobile) so the cvt maybe doesn't have the same range of gear ratios?
In reply to Robbie :
I might have something to do with the inherent variable traction with a snowmobile? They can go from full traction to zero and back again very quickly and repeatedly. That could be hard on the driveline if it doesn't have a lot of slip built in, which the CVT does.
I have some Legends experience and was sad to see them classed in BM because I wanted to get one and autocross it. I looked at the other classes and sent a letter to the SCCA making a case for Legends cars to move to FM. I felt that FM was the best chance to get the car moved to because it wouldn't upset the applecart suddenly. I guess everybody agreed because it was moved the FM the following year. I never did get a Legends car but have taken interest in how they do in FM. The F500 and Formula V's in FM have been developed over years into very competent autocross cars but I haven't yet seen a Legends car fully sorted for autocross. Somebody needs to spend the time and money trying different spring, shock, sway bar and differential set up to find what is ideal. Most Legends cars have spools and that just won't work for autocross.
Kreb said:There's a good excuse for a thread there. I never think of CVTs as being a performance item, but that's what snowmobiles use also, isn't it? How come we don't see more of that sort of thing in car applications?
One of the fastest LeMons cars of all time is a 2-choke CVT miata
https://youtu.be/8wS8W8b9_7A
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