Track dimensions
Discussion
Don't know what the tracks are (but would also love to hear, since I'm now 95% certain that I plan to eventually get one, despite my bitching about a few details which I think shoulda been improved by now
-- cuz I just took another, but more-detailed, look at the Ultima's competition, both in terms of modding a stock car, and the Mosler)...
But regarding the chome-moly (or T46), and whether they'll build it:
They've done a one-off carbon-fiber body and say that they want to give each person an individualized car, so I'd say odds are good. ...T46 or moly will be stiffer than steel for any given weight. I'm not sure whether moly or T46 is stiffer, but would be interested if you ever find out, and in Ultima's prices for each component to be made using a material lighter than steel, if you decide to pursue this:
Who knows, maybe they'll give a lower price if they see that they can do some or most parts at a higher volume than 1 (After all, from 1 to 2 is a 100% volume-increase...and who knows, maybe others will also be interested after seeing Ted's price.)
I'd assume that holding to the outer-diameters which Ultima already has jigs for would be the only option that's not insanely too-expensive (IF they can/will do it...), and assume that in the below notes...
By modifying the wall-thickness, but holding the O.D., you can either go for:
- ultra-light, but same stiffness (but then you may fall well under the minimum weight for most classes, (if you plan to race), or be committing absolute suicide (if an SUV ever hits ya); or you can go for
- same thicknesses as the Ultima's steel uses, but much stronger chassis, obviously (and if I recall right, for chrome-moly, it'll be a little lighter for identical dimensions). The downside of this is that if you go TOO strong (e.g., too thick a wall-thickness), you can negate the point of the crumple-zone and you decelerate at many more g-forces than the human body can take, even in a slow-speed collision.
I think a good compromise would be to only do the rollcage somewhat stronger than the steel which Ted's factory typically uses**, and go for light-weight (and barely stronger than OEM) for the rest: Because after all, if your cage is already being compromised, you should be as worried about 'buying the farm' due to intrusion, as due to excessive g-forces).
**Unless the above design-philosophy was already worked into the Ultima's steel frame, though, in which case, no significant changes would even be needed for the rollcage's tubing...
The chrome-moly-framed Mosler 900R should be a good model, and appears to give that slightly-stronger and slightly-lower-weight compromise: The 900R weighs a few hundred # less than the Ultima, despite having more members, higher bumpers, etc. -- i.e., apparently better crash protection. I'd be happy to just get Ultima framing in moly or T46 which uses their typical layout, but then I'd add some members for more roll-stiffness and more crash-protection from SUV-height bumpers -- some of Jay's, and some of my own ideas (I'm a civil engineer, familiar with space-frames).
Is T46 rust-resistant? Could be an extra benefit, versus using steel... OTOH, with the way I drive and WHERE I drive, I don't plan on any tube on the underbody lasting the years and years which rust takes to develop...
-- cuz I just took another, but more-detailed, look at the Ultima's competition, both in terms of modding a stock car, and the Mosler)... But regarding the chome-moly (or T46), and whether they'll build it:
They've done a one-off carbon-fiber body and say that they want to give each person an individualized car, so I'd say odds are good. ...T46 or moly will be stiffer than steel for any given weight. I'm not sure whether moly or T46 is stiffer, but would be interested if you ever find out, and in Ultima's prices for each component to be made using a material lighter than steel, if you decide to pursue this:
Who knows, maybe they'll give a lower price if they see that they can do some or most parts at a higher volume than 1 (After all, from 1 to 2 is a 100% volume-increase
...and who knows, maybe others will also be interested after seeing Ted's price.) I'd assume that holding to the outer-diameters which Ultima already has jigs for would be the only option that's not insanely too-expensive (IF they can/will do it...), and assume that in the below notes...
By modifying the wall-thickness, but holding the O.D., you can either go for:
- ultra-light, but same stiffness (but then you may fall well under the minimum weight for most classes, (if you plan to race), or be committing absolute suicide (if an SUV ever hits ya
); or you can go for - same thicknesses as the Ultima's steel uses, but much stronger chassis, obviously (and if I recall right, for chrome-moly, it'll be a little lighter for identical dimensions). The downside of this is that if you go TOO strong (e.g., too thick a wall-thickness), you can negate the point of the crumple-zone and you decelerate at many more g-forces than the human body can take, even in a slow-speed collision.
I think a good compromise would be to only do the rollcage somewhat stronger than the steel which Ted's factory typically uses**, and go for light-weight (and barely stronger than OEM) for the rest: Because after all, if your cage is already being compromised, you should be as worried about 'buying the farm' due to intrusion, as due to excessive g-forces).
**Unless the above design-philosophy was already worked into the Ultima's steel frame, though, in which case, no significant changes would even be needed for the rollcage's tubing...
The chrome-moly-framed Mosler 900R should be a good model, and appears to give that slightly-stronger and slightly-lower-weight compromise: The 900R weighs a few hundred # less than the Ultima, despite having more members, higher bumpers, etc. -- i.e., apparently better crash protection. I'd be happy to just get Ultima framing in moly or T46 which uses their typical layout, but then I'd add some members for more roll-stiffness and more crash-protection from SUV-height bumpers -- some of Jay's, and some of my own ideas (I'm a civil engineer, familiar with space-frames).
Is T46 rust-resistant? Could be an extra benefit, versus using steel... OTOH, with the way I drive and WHERE I drive, I don't plan on any tube on the underbody lasting the years and years which rust takes to develop...
I was reading about some article mentioning Formula 1 chassis stiffness. I think it was 15,000 or so. Exactly, why would you need the chassis to be that stiff? Does it mean, the chassis can withhold more G-forces on corners?
It was G-man that mentioned using T46. He said that it is much lighter than the standard Ultime chassis. Also, it is as strong or stronger. It would be great to see an Ultima GTR or Can-Am constructed from a T46 chassis, using carbon kevlar panels, floor pans, and carbon fibre as the dash board pieces. Leave the fiberglass body as is... There are so many things that could be used to lighten the car some more. Lamb Racing sells carbon fibre disc brakes with titanium brake calibers for 2.5k a pair. They also offer titanium springs...
By using the chassis, body panels, brakes, springs, would it be possible to drop the weight down to below 1500 lbs? Using a LS1 or 6 engine as an example...
It was G-man that mentioned using T46. He said that it is much lighter than the standard Ultime chassis. Also, it is as strong or stronger. It would be great to see an Ultima GTR or Can-Am constructed from a T46 chassis, using carbon kevlar panels, floor pans, and carbon fibre as the dash board pieces. Leave the fiberglass body as is... There are so many things that could be used to lighten the car some more. Lamb Racing sells carbon fibre disc brakes with titanium brake calibers for 2.5k a pair. They also offer titanium springs...
By using the chassis, body panels, brakes, springs, would it be possible to drop the weight down to below 1500 lbs? Using a LS1 or 6 engine as an example...
4130 is no stiffer than most other steels. It is however quite a bit stronger/tougher. This means that you can get away with thinner wall section on the tubing. This is the reason that most 4130 chassis are lighter. If you want to increase stiffness the best way is to add more triangulation and/or increase the diameter of the tubing. The downside to 4130 is that you must TIG weld it and preferably normalize the welds afterwards. You can easily end up with brittle welds if you are not experienced.
If you want to seriously reduce the weight of the car I would look into getting light weight body mouldings made from kevlar/carbon. While the Ultima body is very nicely made with an excellent finish it is very heavy. I can pick a TransAm front clip up with one hand (its a lot bigger than the Ultima clip). I can't say the same about the ultima body. I think the reason the Ultima body is so thick is to avoid ripples and sags.
Regarding why F1 cars need to be so stiff, it is so that the suspension pick up points don't move relative to each other under G loads. Also they run very stiff springs and if you didn't have a stiff chassis the chassis would flex rather than the shocks moving.
If you want to seriously reduce the weight of the car I would look into getting light weight body mouldings made from kevlar/carbon. While the Ultima body is very nicely made with an excellent finish it is very heavy. I can pick a TransAm front clip up with one hand (its a lot bigger than the Ultima clip). I can't say the same about the ultima body. I think the reason the Ultima body is so thick is to avoid ripples and sags.
Regarding why F1 cars need to be so stiff, it is so that the suspension pick up points don't move relative to each other under G loads. Also they run very stiff springs and if you didn't have a stiff chassis the chassis would flex rather than the shocks moving.
Nothing wrong, in fact it would be ideal. The problem is the cost and technical difficulty of getting there.
If you do all the extra work and make the chassis stiffer it will be heavier and there's already another thread covering that.
If you need stiff suspension, say for racing, then you need a stiff chassis for the suspension to act against.
Most of us are, or will be, running road cars with relatively soft suspension so do not need the chassis any stiffer than Ultima have made it.
Steve
If you do all the extra work and make the chassis stiffer it will be heavier and there's already another thread covering that.
If you need stiff suspension, say for racing, then you need a stiff chassis for the suspension to act against.
Most of us are, or will be, running road cars with relatively soft suspension so do not need the chassis any stiffer than Ultima have made it.
Steve
Following on from what pstockley said about 4130 and other high strength steels. The design of the Ultima requires a large number of holes to be drilled in the chassis to mount body panels, wiring, brake lines, etc. With a tough steel this is not going to do anything particularly useful to the fatigue life of the chassis unless you provide an alternate means of attaching these parts...
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