racerfink said:
Needs more LSX. Next time I see Andy I need to ask him about this.
stroker said:Titan4 said:In reply to stroker :
OK, so how about this:
Tube frame, fiberglass body, VW Type IV engine (think Porsche 914) built from scratch in my garage.
Something like that with a bit more variability in drivetrain is exactly what I was thinking when I made the original post.
You say you built that yourself? Got any more information, perhaps a Build Thread would be appreciated by The Hive?
Me too! more info please.
racerfink said:
Thanks for that, I hadn’t heard of that history before... definitely an enjoyable read.
If you could only imagine All Those old Dirt car tube frame chassis out there, Dirt car body, V-8, No Aero. Sadly 99% are offset chassis.
For Challenge type rules there Isn't a MFG. to align with, For a Top Dog Open Class, ' Awesome ' but pretty restricted use besides the Challenge.
If you could only imagine All Those old Dirt car tube frame chassis out there, Dirt car body, V-8, No Aero. Sadly 99% are offset chassis.
For Challenge type rules there Isn't a MFG. to align with, For a Top Dog Open Class, ' Awesome ' but pretty restricted use besides the Challenge.
The Hillclimb guy's seem to make good use of them.
I'm reading through the SCCA GCR. The structure of "sports car" racing seems to have changed significantly while I've been not paying attention. We now appear to have P1 and P2 categories which appear to lump all the old B, C and D Sport categories into two classes. If we were to build a mid-engined "Challenge Sport Car" we'd pretty much be tied to current SCCA P1 and P2 rules, correct? So a front-engined car using an old dirt track/stock car frame would have to comply to the SCCA Sports Car rules or something else?
stroker said:If we were to build a mid-engined "Challenge Sport Car" we'd pretty much be tied to current SCCA P1 and P2 rules, correct?
The SCCA GCR also has rules for ASR (A Sports Racer) as a regional-only class. It's pretty open allowing bigger displacement than the P1 and P2 rules. Historically, ASR is where you ended up if you converted your old F5000 car to a single seat sports racer but it has become something of a catch-all for sports racing cars. I don't think there is a need to be mid-engined there so a front-engined car would fit also.
What about the possibility of using a kit car frame as a starting point? Something like a Fisher Fury for a front engine or maybe a Midlana or a FFR 818 mid engine something? I doubt a kit frame could be sourced cheaply enough to come in anywhere near Challenge budget, though. Any ideas on kit car frame candidates?
I'm thinking a ratty looking Bradley GT dropped on to a tube frame with a big ol' V8 would be just about perfect.
The OP called for a build budget for around Challenge money - I don't see any of the next three pages beating the cost:performace ratio of the second post by Driven 5 recommending an F600.
2000 dollar limit could be tough Because we need Repeatability in the Building of them, But 3500 to 4000 could build some .
Again I think simi equal Chassis /Body rules and engine rules that are Simple, N/A V-8 5L 302ci 3.5L turbo, 2800 lbs, Chassis can be one we make at Home from a Set of Plans Like the Old Days, Maybe Start with a C4 Frame and then a Spec Set Of Bars and again a simple aluminum Dirt car body to Match the engine, or Not
I Don't see this being a class for anything From a Factory car base. you could put a GM 4t80 w a SB Chevy in the back of a c4 easy enough and Because I have One I see where it could be Darn Light, and use Loads of Factory parts,In A Slolom stock is ok But to Really race you need Better Susp.parts
In reply to GTXVette :
While not in the same ballpark as the Challenge, the original FSAE goal was to make a $5k race car. So combining older FSAE work with Challenge restrictions nets you a pretty interesting car. But not that much unlike some of the 70's era inexpensive sports racers. I can't recall the brand name of the car Per found quite a few years ago- but it's not a super expensive material make.
I also don't see the repeatability as a challenge, ether. What it means is that the first chassis will be expensive, as you have to build some jigs around cutting and welding them. But from there out, they won't be too hard. OR- the design changes to a simpler to assemble process- instead of putting a lot of tubes together, you get sheets, bend and connect- which should reduce the amount of connection work. Heck, one could even find some of the less expensive structural sheets out there- like honeycomb structure sandwiched by aluminum. The point there is that there are other way to make a chassis than just steel tube welding. In terms of other parts- brakes, fuel systems, electrical, etc- while not the top of the top stuff- circle track parts tend to be quite reasonable in cost, even brand new.
In terms of the car- mid engine for sure. And I would not throw aero work out- there are some plenty good CFD tools out there that are cheap enough to make a good body and aero devices around.
So in summary- take a midlandia, alter the shape to fit under a easy to make but aero capable body, and choose a powertrain. Done. You'll end up with what is very close to a spec racer of whatever era (Renault, Ford, Honda...). Which is a very good car.
In reply to alfadriver :
Per's old sports racer was a LeGrand Mk 18.
It's still a pretty complex car and would be tough to do on a spec budget. That is one of the benefits of the F500/600 chassis - it's very simple, and thus cheap - solid rear axle, cheaper suspension design, aero restrictions, 10" wheels, etc.
In reply to alfadriver :
The challenge with using sheets to build up a chassis with is that cars tend to have a number of “point loads” introduced into them. This is based in part from following palatov’s original dp1 development back in the day (which I followed independently from joining here), where he looked at going with carbon & nomex (?) honeycomb panels. But anytime you went to mount something, it required cutting the sheet out oversized and dropping in a plug that would help distribute that load out into the panel without creating a localized over-stress. Which is something you’re going to have to work through since all the GCR’s that I know of specify steel-tube roll-over/cage structures.
now, perhaps aluminum sheet with aluminum honeycomb can mitigate this... I mean, Porsche did it with their prototype cars back in the ‘60’s, right?
interestingly enough, palatov’s cars grew out of reading FSAE forums, and people proposing that an Awd FSAE was... impractical ? Impossible? Something like that.
Ian F said:In reply to alfadriver :
Per's old sports racer was a LeGrand Mk 18.
It's still a pretty complex car and would be tough to do on a spec budget. That is one of the benefits of the F500/600 chassis - it's very simple, and thus cheap - solid rear axle, cheaper suspension design, aero restrictions, 10" wheels, etc.
This may be my personal bias but I look at F500/F600 as more like a kart than a car. Regardless of that it doesn't have two seats per my second post in the thread, #4 overall. I should have been more specific in my original post. It's also possible that the rules have changed for LeMans prototypes without my being aware--i'm thinking back to the early 70's and I was under the impression that "Sports Cars" were still required by the rules to have two seats as the original Can-Am cars did. I'll certainly concede that something like a F500/F600 would be the most cost-effective answer to my original question, but I doubt anyone would want to drive one in an endurance race--or am I wrong about that?
In reply to sleepyhead :
My limited knowledge of structural engineering would make me think that sheet aluminum honeycomb would be very similar to carbon honeycomb. Which would say that the loads would have to be designed around.
IIRC, Carroll Smith book used sheet design for it's race car book. The ONLY reason to go down this path is if it's faster and cheaper to make in bulk. Otherwise, cutting and welding does a good job.
The on really interesting development I've seen are some FSAE teams using folding sheet design for the base chassis- where the big issue is how to cut the folds so that they fold correctly- there was an interesting article in Racecar Engineering about it. Seemed like something that could be translated to mass production if perfected. Making bulk sheets that can be later cut and folded would be a whole lot faster than laying out and curing every single chassis (it seems to me).
Ian F said:In reply to alfadriver :
Per's old sports racer was a LeGrand Mk 18.
It's still a pretty complex car and would be tough to do on a spec budget. That is one of the benefits of the F500/600 chassis - it's very simple, and thus cheap - solid rear axle, cheaper suspension design, aero restrictions, 10" wheels, etc.
From a build standpoint, they are both tubes cut (sometimes bent) and welded together. The difference is the suspension. And the front is still A arms- just using pucks instead of springs and shocks. The rear is where the big difference is. And while a live axle will work really well with front engine cars OR some kind of chain or belt drive to the axle- that doesn't work so well with powertrains fully located behind the driver. Either way the engine is laid out, having the trans bolted to it would mean it can't roll, therefore a live rear axle isn't feasible.
So at some point, this spec design would have to decide on using a car engine or a bike/snow mobile engine.
My thinking would be a simple FWD powertrain would be the most economical choice. And given the numbers, a transverse powertrain would be the most abundant (and economical).
In reply to stroker :
Probably not, depending on the track. For example, even with a custom formed seat, I'm sure the 12 Hours of Sebring would be brutal even for hour or so long stints in an F500/600.
Some sort of budget-oriented sports racer built to for a spec series would require a fairly tight rules package. A frame either purchased from a provider or built and then inspected to be compliant. Bodywork would almost certainly need to be sole-source to maintain some level of equality. The suspension and drivetrain could be sourced by the racer and could arguably be fairly equal. But the simple fact is the more complicated the car is, the greater the chance someone willing to spend more will be able to gain an advantage. But that is always a problem with a spec series.
In reply to alfadriver :
With the limited suspension travel a race car typically has, I can't see why a chain drive wouldn't allow some engine to axle roll variation with some sacrificial guides.
I'm never foresaw the original query developing into a "spec series" discussion. Personally, I find the mental image of a race with a couple dozen or so GRM entrants ranging from GT to Prototype cars of their own construction (not necessarily their own design) to be a lot of fun to think about. That thought is doubly appealing as IMHO a 12 hour endurance race would be a terrific counterbalance to The Challenge and the UTCC. Based on the comments so far, it sounds to me like you guys think there's at least a small amount of interest in something like a generic tube frame (something like a Midlana or an 818) which could use various suspension sourced from a street car for the front and a plethora of longitudinal/tranverse powerplants for the rear.
I have an idea for such a car and I'd love to build one at some point in the future when I'm employed and have some money to spend...
In reply to Ian F :
I think you took my comment wrong- a live axle in a race car is much easier with ether a front engine whatever OR a chain/belt drive (since that's what F500/600 is). Making a live axle work with a mid engine and a transaxle is pretty much impossible. A live axle like De-Deon is possible, and simple, though....
In reply to jstein77 :
whats the mumbo jumbo under the car?
fidelity101 said:In reply to jstein77 :
whats the mumbo jumbo under the car?
air skirt, with a vacuum run by a second motor using an exhaust fan from a tank. Its the "Sucker" Vette:
https://grassrootsmotorsports.com/articles/how-turn-corvette-2000-sucker-car/
In reply to stroker :
Ah... true... not sure how it went down that rabbit hole... so - no spec series.
I suppose some existing cars to ponder are some of the current formula cars that are based on an existing FWD engine and transmission combo fitted to a tube frame constructed to some level of safety standards. Then the trick would be creating some level of parity formula if desired. Otherwise, one particular combination will eventually rise to the top and if you don't run that combo you won't be competitive.
In reply to alfadriver :
Yes - I still had my head in F500/600 land running a small MC engine/trans and chain drive. Otherwise, I agree - as soon as we go to a FWD car drive train we'd be in IRS world.
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