F1000 Rules Discussion

[Mike B]

Is it possible that the SIR size could be determined using Marshall's line of reasoning on CR? Calculate which current engine has the smallest total intake cross-sectional area and apply that to the rest of the engines. The problem I have with having a Dave Finch working it out is that I'm sure he won't do it for free. I don't have the money to do it and I doubt that anyone else will. I also understand there were some hard feelings in the GTL ranks when it was announced that all competitors had to buy their SIR from him. I may have some facts incorrect, but I plan to make my own SIR. Isn't that the point of a "free" class?

I'm inclined to stick with F1000 and limit it to liter engines. Sean's opinion carries a bit more weight since he actually has a car. If there is a group that is interested in F600, they're welcome to follow along, but they'll have to do their own leg work. I'd like to keep this "project" uncluttered. It may be more convincing when it comes time to sell it the SCCA.

As soon as I have some free time, I'll redraft the rules and post them to continue the momentum. I would also like to start thinking about putting together a proposal and pursuing Dave G's suggested course of action. Please keep the discussion going.

[RobLav]

Mike,

I like Stan's idea - using the nominal 12.5:1 compression ratio. Either that or use an '04 R1 as the basis. Not an earlier, less powerful, version to determine inlet restrictor size. Too small of an inlet restrictor will cause people to spend more money - ie - camshafts that optimize the area under the torque curve at RPM's below the restrictor inlet air volume. That would in turn devalue the need for 6 gears. The '04 R1 is about in the middle of the relatively current performance numbers in the 1000cc bike engines.

But I would not agree to any rule that says I have to purchase any particular item (SIR included) from someone, like the heresy GTL SIR. I'd prefer to either source it myself or make one.

As it stands right now, it is highly unlikely that two or more F1000 cars will be on the same track at the same time competing against one another. So the exact SIR dimension is not really that critical. Something within a milimeter in diameter will do. But if we have some solid specs, then people will have something to build to.

[Stan Clayton]

Okay, guys...take a deep breath. There may have been a time when Finch was the only guy that sold SIRs, but AFAIK one never had to buy one from him. You could always make your own, and you still can. Plus, there are at least a couple of other shops that sell them. Gimme a few and I'll post their websites.

Stan

[Dave Gomberg]

Is it possible that the SIR size could be determined using Marshall's line of reasoning on CR? Calculate which current engine has the smallest total intake cross-sectional area and apply that to the rest of the engines. The problem I have with having a Dave Finch working it out is that I'm sure he won't do it for free. I don't have the money to do it and I doubt that anyone else will. I also understand there were some hard feelings in the GTL ranks when it was announced that all competitors had to buy their SIR from him. I may have some facts incorrect, but I plan to make my own SIR. Isn't that the point of a "free" class?

It is not true that anyone has to buy their SIR from Dave Finch. If you read the SIR rules (currently for GT, but likely to be used in other classes as well), there is a statement of SIR requirements. Anyone who wishes is free to make their own according to those requirements. It is unlikely that you will be able to make as effective an SIR as the one Dave Finch makes and sells, but if that's what you want to do, go for it. What I mean by "effective" is getting as much air flow through the required restrictor size as the one sold by Dave F.

As for what Dave will charge for his advice, you are incorrect. We have had the benefit of his knowledge for another situation (it is too soon to talk about it) without any discussion of recompense.

Dave

[Craig]

Stan - While you have a point about the max efficiency of the engines, I hate to just throw out an engine from the list of options. The ZX10 engine is actually a fairly decent choice. Unless you mean to suggest that a CR of 12.7 is 'close enough' to a limit of 12.5. You have a good point about trying to limit power that way, but will you want to police a rule by having to measure combustion chamber size? Just let the CR be open, getting above 13:1 is pushing the limit of these engines even surviving a single pull on the dyno in one piece.

I like the rest of the ideas. I'm not sure I'd like to get rid of the boosted 600, but for the sake of cost and getting the class running MikeB has it right, leave them out for now. What about boosted 1000's? Running through the same size restrictor, they theoretically should make similar ultimate power numbers. FSAE allows the competitors to run boost or N/A, but with the same size restrictor. (unless they changed it recently) There really doesn't seem to be a correlation between the results and running boost or no boost. Just remember, as the rule makers you have to think of the restrictions you want to impose. As a car builder, I'm thinking of ways to get more speed. If it isnt in the rules, someone will go ahead and try it.

Craig

[Stan Clayton]

Sorry I wasn't clear, Craig, but yes, the Kawi would be legal. I was just musing about the relative thermal efficiencies of the Big Four engines, and what that suggested for an SIR. ANY liter engine would be legal, whether someone picked an old 10:1 motor or the newest Superbike engine. But thank you for reminding me...we need to specify normally asmatic liter engines...

Stan

[Mike B]

As I said, I may have some of the facts incorrect so I stand corrected, with apologies to Mr. Finch. I'm also all ears with respect to what Raetech might be able to offer this group. To be honest, I've never even seen an SIR (that I know of.) Can someone point me to one online?

[Dave Gomberg]

http://raetech.com/Motorsports/Restr...strictors.html

Dave

[Stan Clayton]

I'm not sure I'd like to get rid of the boosted 600, but for the sake of cost and getting the class running MikeB has it right, leave them out for now. What about boosted 1000's? Running through the same size restrictor, they theoretically should make similar ultimate power numbers. FSAE allows the competitors to run boost or N/A, but with the same size restrictor. (unless they changed it recently) There really doesn't seem to be a correlation between the results and running boost or no boost. Just remember, as the rule makers you have to think of the restrictions you want to impose. As a car builder, I'm thinking of ways to get more speed. If it isnt in the rules, someone will go ahead and try it.

This is a very good point, Craig, and one that I had completely overlooked. I checked the 2006 FSAE rules and they have not changed on this point. (See page 54 of the 2006 FSAE Rules.) The 670cc restriction is based on unrestricted intakes in DSR. When all engines have to breath through a single intake restrictor, turbocharging doesn't make appreciably more power or torque than the same engine without a turbo. It just moves the curves around. In other words, the engine will make the same power with a turbo, just at a lower RPM. This might actually promote longer engine life compared to twisting every last revolution out of non-turbo'd engines.

It is going to take some time to get our noggins around this concept, but please don't reject it on emotional grounds. If you have facts to refute what FSAE does, and what Im proposing, I'm all ears.

I've done some further refinements to the rules I posted above and will post the revised version in a subsequent post.

Stan

[formulasuper]

So, after reading that the SIR is the big equallizer I'm wondering if the Hayabusa engine with this same sized restricter would make equal power of the 1000cc engines. Anyone know? A Busa would surely last longer if restricted down in power, right?

[redlinep1]

Hi Stan,
I have been following both treads for some time now and am very interested in this concept and class. One question I have regarding carbon tubs ... I would be interested in knowing the company looking at importing into the US. This is very appealing to me to drive/build a current car with todays tecnology given the pottential speeds these cars are going to be going. Any information on this tub or other companies producing these for sale would be greatly apreciated. I believe the modern tubs need to be allowed for a mear safety concern....only me 2 cents, as an outsider.
Thank you for all the hard work you guys are doing to promote a great concept

mike
mike@redlinepromotions.com

[Stan Clayton]

So, after reading that the SIR is the big equallizer I'm wondering if the Hayabusa engine with this same sized restricter would make equal power of the 1000cc engines. Anyone know? A Busa would surely last longer if restricted down in power, right?

In practice we would actually assign a slightly smaller SIR to the Hayabusa than for the liter engines, as well as slightly larger SIRs for smaller engines. SIRs can be made finely enough to account for engines down to about 200cc difference in displacement. That implies 5 sizes to cover engines in 200cc increments from 600cc to 1400cc.

And yes, an SIR sized for 185hp would almost certainly prolong the life of a Hayabusa.

Stan

[Stan Clayton]

I have been following both treads for some time now and am very interested in this concept and class. One question I have regarding carbon tubs ... I would be interested in knowing the company looking at importing into the US. This is very appealing to me to drive/build a current car with todays tecnology given the pottential speeds these cars are going to be going. Any information on this tub or other companies producing these for sale would be greatly apreciated. I believe the modern tubs need to be allowed for a mear safety concern....only me 2 cents, as an outsider.

Mike, I don't know if a deal has been finalized between the contructor and an importer. I will check and post the results here. Stan

[redlinep1]

just curious..which constructors were interested in bringing over tubs...

[Bill Maisey]

UK constructor, OMS, builds a carbon tub, motorcycle engine car. See a photo here: http://www.billmaisey.com/oms2/aboutus2.htm

Interestingly, OMS will convert customer's tube frame cars to the carbon version for about 10,000 pounds. Look here: www.omsracing.co.uk/Upgrades.htm

[Stan Clayton]

Okay, I cleaned it up a bit more and changed the engine section. The turbo provision is deleted, and I have narrowed the engine choices to more in line with what folks have actually asked for.

Stan

FORMULA 1000 PREPARATION RULE
Formula 1000 is a restricted class for single seat, open wheel racing cars as defined by these regulations.

A. Chassis: Monocoque or tubular chassis construction.
1. Engine oil or water tubes are not permitted within the cockpit.
2. Chassis of non-metallic composite construction shall be proven to meet FIA specifications for non-metallic composite chassis prior to being submitted to the SCCA for homologation. Contact the SCCA national office for a list of the relevant FIA specifications/SCCA requirements.

B. Bodywork and Airfoils: Maximum dimensions per Formula Continental rules.
1. No part of the suspended part of the car shall extend more than 1 cm (0.394 inches) below the plane forming the bottom of the tub or chassis.

C. Engines: Normally aspirated production 4-stroke motorcycle engines up to 4 cylinders are the only permitted engines.
1. Carburetion and fuel injection are unrestricted.
2. An SIR is required, based on engine displacement. See 2006 GCR page GTCS-40 for SIR rules.
a. Over 900cc and up to 1100cc – 25.0mm
b. Over 1100cc and up to 1300cc – 24.75mm
3. Lubrication system is unrestricted.
4. Cooling system is unrestricted.

D. Suspension: Carbon fiber and titanium suspension components are prohibited.
1. Springs: Steel only.
2. Shock Absorbers: Steel or aluminum alloy body only.

E. Brakes: Unrestricted, except that carbon brake rotors are prohibited.

F. Wheels and Tires: Unrestricted providing wheels are metal.

G. Transmission: The gearbox shall contain not more than six (6) forward gears.
1. The use of an automatically shifted gearbox is prohibited.
2. Electric and/or pneumatic assisted gear change mechanisms are permitted.
3. Rear wheel drive only is permitted.
4. Final drive ratio and gear ratios are unrestricted.
5. Differentials are unrestricted, except that electronically controlled differentials are prohibited.
6. A reverse gear is not required.

H. Weight: 900 lbs minimum as raced with driver.
1. Pre-1993 FC cars with motorcycle engines may compete at their 2005 GCR specification and weight.

[RobLav]

Getting better Stan - thanks.
One question and one comment:
1) How did you determine the SIR sizes? I'd like to see the math behind it if it is possible.

2) Recommend bodywork and airfoils be to "maximum"of FC sizes. I'd prefer to leave it open and see where it goes.

At least under these rules my Hayabusa is legit.

[Stan Clayton]

The SIR size is not derived from an algorithm, but rather from extensive dyno testing of 4-valve, 2-valve and rotary engines by Raetech. The 25mm and 24.75mm were just estimates that I didn't intend to leave in the thread, and can be disregarded. Dave Gomberg will get us a "real" number at the appropriate time, but the larger engines will have a slightly smaller SIR to compensate for their slight performance advantage at low and medium RPMs.

And yes, the idea was to permit the Hayabusa, albeit in 'strangled' form. In fact, we should provide that engines may be over-bored 0.5 mm, or whatever the first over-bore is so that if one over-bores an engine it can continue to be legal. A 0.5mm over-bored Busa has 1315cc, so (ignoring the specific SIR number), we'd have...

a. Over 900cc and up to 1115cc – XXmm
b. Over 1100cc and up to 1315cc – XXmm (minus 0.25mm)

Rob, I'm not sure what you mean, so why not take a short at writing the wing dimension line, okay?

Stan

[Radicalone]

If you are going to use SIR's then why restrict it to motorcycle engines only.If you allow rotaries and two strokes you may get some transfers from F500 and FM that like their motor types but would like less restrictions on the chassis side.What difference does it make if you equalize everyone with SIR's.

John

[Art Smith]

Stan-

here's several thoughts on current "dark holes" that I believe should be avoided given you're starting with a clean piece of paper:
1.) is: No part of the suspended part of the car shall extend more than 1 cm (0.394 inches) below the horizontal plane forming the bottom of the tub or chassis.
suggest: delete the word "horizontal". the rule is not objectively enforceable without a further statement(s) defining when/under what conditions.

2.) is: Flexible or moveable aerodynamic skirts are prohibited.
suggest: define all words in objectively verifiable terms/numbers. everything is flexible and therefore moveable! what is an "aerodynamic skirt"??? there's already far too many rules in my opinion that allow well intentioned folks that have never sat through one aerodynamics class to "know it when they see it".............................. is a 3/8" thick long narrow strip of jabrock on the bottom of both sides of the car an "aerodynamic skirt"???

3.) is: It is not permitted to construct any suspension member in the form of an airfoil or to incorporate a spoiler into the construction of any suspension member.
suggest: define in objectively verifiable terms/numbers what is an airfoil and what is a spoiler. is Mil-T-6736 streamline tubing an airfoil? is a flat plate an airfoil? how about rectangular tubing, is it an airfoil? if the "intent" is to require/encourage/force designers to use round tubes, then require all suspension members be constructed out of round material; round within plus or minus 0.XXX inches (ie: objectively verifiable with a piece of simple test equipment).

4.) is: Brakes: Unrestricted except carbon brake rotors are prohibited.
question: is it your intent to allow titanium rotors??? if not, suggest requiring use of cast iron or steel rotors.


Art
artesmith@earthlink.net

[Mike B]

John,
The name of the class is F1000. It is not intended to be the open-wheel version of DSR. That's what FS is for (does that sound familiar?) Scope creep needs to be prevented immediately and up front. To that end, we ruled out 600cc engines to keep the class pure. IMO, allowing up to 1300cc is creep.

Art,
I think the intent of Stan's draft is to be simple. This isn't a spec class but by defining every little excruciating detail, the rules would dictate what the design looks like. Stan's wording is virtually identical to what's currently found in the GCR and to my knowledge, there hasn't been any problems. Keep the rules free(er) and let the creativity flow.

All,
What's the current thinking on forced induction vs. NA? As much as I love turbos, my vote is for NA to keep things simple and keep costs down.

[RussMcB]

Art,
I think the intent of Stan's draft is to be simple. This isn't a spec class but by defining every little excruciating detail, the rules would dictate what the design looks like. Stan's wording is virtually identical to what's currently found in the GCR and to my knowledge, there hasn't been any problems.

I think Art's suggestions are very good and you should consider them seriously. Although you may not be aware of problems, they exist! I see MANY discussions about what is or isn't legal, especially around ground effects and aerodynamics, and many people involved in those discussions state that they wish the written rules were more clear. I think Art is simply suggesting that you have rules that are very easily measured and take this opportunity to avoid problems.

[Craig]

I'll agree with you Mike, keep this class at natural aspiration. The whole idea of converting these cars is to lower costs. A turbo sounds more like DSR to me.

Craig

[Stan Clayton]

Man, I take my wife out to a nice restaurant for supper and come back to all kinds of good stuff...

Guys, Art and I have traded many emails on items of mutual interest (racing!) and I highly value his input...and as always, it is spot on! Art, you may have noticed how much I've carved off the original proposed set of rules. It seems that every time I look at them I see more items that need to go or be modified, so thanks for pitching in with these great observations.

1. Agreed! Delete the word.

2. Some of this stuff reads like it was written in the days of Jim Hall's Chaparral 2J... A car that complies with the FC dimensions and with point 1 above will pretty much comply with this, so here is another redundancy that can go.

3. I'm not certain of the intent of the original wording, though my guess is that it was to preclude downforce generating suspension pieces. In any event, the GCR (p. 131) defines an airfoil as "An aerodynamic device or part of a car which the flow of air over its surface will generate a vertical force by creating a pressure differential between top and bottom surfaces." The FIA, of which SCCA is a member, defines an airfoil as a "section generated by two arcs with different curves and/or centres joining a leading edge at the front to a trailing edge at the rear". Neither round, oval, streamlined tubing, nor rocker arms will violate these definitions in normal service, so do we really need this passage? Or is there a quiet conspiracy out there just waiting for us to drop our guard so they can roll out inverted Clark-Y shaped rocker arms...?

4. My only agenda with the brakes is to not require ferrous calipers. Pretty much everyting else is open to discussion. Want carbon and/or ti brakes? Speak up!

Thanks Art!

Stan

Edit: I edited the rules package above to reflect this post.

[carnut169]

I think Art's suggestions are very good and you should consider them seriously. Although you may not be aware of problems, they exist! I see MANY discussions about what is or isn't legal, especially around ground effects and aerodynamics, and many people involved in those discussions state that they wish the written rules were more clear. I think Art is simply suggesting that you have rules that are very easily measured and take this opportunity to avoid problems.

Russ is right here Mike- aero over at the XSR camp is a pia! Certain CSRs have been protested several times because of the tunnels (among other things).

I think 1300s will have a disadvantage in F1000 b/c they weigh more and won't make more hp w/ the sir. However- they should last a LONG time since they will be only running at 80%...
In the long run I bet its mostly 1000cc engines.

[RobLav]

Good comments above.

1) Appreciate allowing the 1300cc, though I already built my engine for CSR with bigger cams and had it flowed by RFD. I guess we'll see if there really is greater lower RPM torque.

2) In regards to suspension members, how about simply stating "preclude downforce generating suspension pieces".

3) Let brakes be free. Since these cars will probably require an alectrical power generating device (like an alternator), the technology is available to use the braking system to generate that power. It would be nice to see if that goes somewhere. It might be "pie in the sky", but it's in the spirit of keeping the rules a bit more open.

4) Turbo / super charger OK. I can't see a competitor running one of these on a 600cc engine with the same restrictor sizes.

5) WRT body and aerofoils, I'll have a look at the FC specs and write something up, but what I had in mind is something like "airfoils are not a requirement for this class". If they are utilized, then the max dimensions are per FC rules.

Thanks all...

[Mike B]

Sean,
I agree that there is a lot of disagreement over underbody aero in the DSR/CSR group. However, the way Stan's package is written, the underbody is virtually wide open. The only thing the 1cm rule does is prevent skirts (I think.) That's the beauty of it!

Rob,
I think the way Stan has the aerofoil section written accomplishes what you're asking for. However IMO, aerofoils SHOULD be a requirement but only to maximum dimensions. This requires guys to get creative when they race at Pocono or Daytona and I really enjoy seeing how people solve a given problem.

Stan,
What are the realistic chances that if the aerofoil-shaped suspension thing is removed that somebody will exploit it, to the detriment of the class? My guess is pretty slim since it's the only place it could be exploited. So why not just leave it in?

[formulasuper]

I'm not sure I understand why there should be a limit on airfoil max size. Can someone explain?
Also, I agree that the Busa is heavier & should not be a threat with correct SIR.

[Mike B]

Scott,
To me, it's more of a philosophical standpoint. I have a preconceived notion (as most of us do) of what a formula car should look like. Leaving wings wide open will permit cars with Sprint car wings, 5-tiered FSAE wings, or six foot wide wings. Someone might even show up with a split rear wing! There needs to be some uniformity (IMO.)

[Stan Clayton]

G'Mornin' guys!

First to Rob's points...

1. While your Busa may not be an ideal candidate for this class there will always be guys who want the option of a less stressed and longer lived engine, and yet still be reasonably competitive. FWIW, I agree that the Busa might actually be at a slight disadvantage, as I understand it is somewhat heavier than a liter engine. But that's a choice competitors would make with open eyes.

2. Creating consistent downforce is a tricky challenge. The aero behavior of a downforce creating suspension piece would be all over the (aero) map as the suspension compresses and rebounds, so in a practical sense I don't see folks trying this approach, especially when wings are already legal. IMO, adding vague language just invites bickering.

3. Alternators are already legal (as part of the engine). However, that still leaves the question of brakes unanswered. What do you guys think...and why?

4. I too would leave turbochargers legal, but that's just my preference. After all, with equal SIRs, a turbo engine can't make any more power than a non-turbo'd engine...it will just make the same power at a lower RPM. Turbos do add cost and weight, though, which puts them at somewhat of a disadvantage in those senses. Still, it's an approach that I would prefer to leave open to innovation.

5. Knowing what I know about wings, I would certainly use them. Maybe guys driving 1100 lb cars with 140hp around Pocono and Daytona can go faster without them, but that may not be true for cars weighing 200 lbs less and making 40 more horsepower. In any case, by removing the statement that wings are required, I read the new rules to only regulate the maximum span of the wings...not require them at all (see "I" and "K" in the table of dimensions). Still, I'm looking forward to Rob's suggested wording.

Mike, I think you've hit the nail on the head about undertray aero in xSR. Furthermore, if one reads the undertray aero section in FC (2006 GCR page FCS-21, paragraph B.4.c) it is pretty clear to me that this wording is open to the same sort of debate as in xSR. But unlike xSR, F1k is limited to a maximum body width of 95cm (as opposed to 221cm!). Therefore, the opportunity to create appreciable downforce is severely constrained, so my suggestion is to leave this area open to innovation. There probably isn't much to be gained here and by deleting the wording we avoid a lot of pointless squabbling.

As for why I would delete the "suspension member in the form of an airfoil" wording, my rationale is based on tolerencing (in the engineering sense). Granted that aero tubing is not an airfoil in the SCCA's definition, what if it is not "perfectly" level? Then it is an airfoil! What deviation from perfectly level are we going to allow? In a technical sense, to actually enforce this rule, we would almost certainly have to require all suspension pieces to be round, and rocker arms might not be legal. As it is, no one extrudes "airfoil" tubing, and I haven't seen any airfoil-shaped rocker arms, so why include wording that is just a point of contention?

Hope that helps!

Stan

[John]

Stan,

I am glad to see you have the weight at 900, that should keep the titainum nonsense that is going on in Xsr away. I went from FC to DSR cause I had no-one to race and I wanted to go faster, but the DSR I have now is too heavy. To get the weight down all I need is a new carbon fibre body, carbon composite floors, new wheels, and lots of titanium...

I can make 900 easy without the floors or body, I wonder how a Maloy would look as a single seater?

John Howarth

[Stan Clayton]

Hey John, how ya doin'? Sorry you couldn't make it to Phoenix!

The situation in DSR is complex, as one would expect in an evolving class...and which is something we should bear in mind as we write the rules for F1K. In prior decades DSRs were rather underpowered, so constructors tended to build small and at the minimum legal weight to get the maximum performance from the power available. Nowadays DSRs are putting down much more power than in prior decades and the cars' size (and weight) has grown to accommodate that additional available power. In order to claw back the losses that come from weight gain, folks are spending big bucks to buy lighter pieces for their cars, and I'm not sure that's good for the long term health of the class.

Which brings me to the weight of F1K. If anything, I am inclined to set the minimum somewhat higher to avoid the worst excesses of what we see happening in DSR. Here's an example that illustrates my point. IIRC, Sean's converted FC weighs 765 lbs wet, but without gas or driver. Adding 10 lbs of residual fuel and a 180 lbs driver, we get 955 lbs. While I am confident Sean could take some weight out of his car rather easily, trying to get down to that magical 900 lbs might well turn out to be an expensive proposition. And to what good? I'd like to encourage innovation of design in F1K, but not merely where it means spending tons of money. The question of minimum weight in F1K is somewhat unsettled in my mind, and I'd like to see some more discussion of it. Perhaps the 930 lbs for m/c powered FCs is a better number.

Stan

[John]

Stan,

I would be happier to see it at 1000lbs, I am over that now with all the body work and on the starts my car has way more power than anything around me, and I am ususally in the front part of the grid with the 1st or second mazda even with over 1000 lbs and a car that we are still sorting big time. I think I could make 1000ibs with no fancy stuff pretty easily in a formula car, and I would like to see normal people weight the same as me (I am pretty tiny) so they don't have any excuses. I think at 1000lbs you have a very fast car, with really good brakes without spending a zillion on lightweight stuff. The body for my car is all carbon and VERY expensive, so stay away from a wieght that is too low.

I would think that fully sorted an F1000 at 1000 LBS would be under the FC track record anywhere with a decent driver.

Cheers,

John

[RobLav]

That's kind of cool - 1000cc at 1000 lbs. Goes well with F1000.

[Stan Clayton]

While I certainly understand John's perspective on DSR, I am not supportive of a minimum weight that will mean adding substantial amounts of weight to an otherwise stock FC starting point. If Sean's car weights 955 lbs with iron calipers and with no weight saving measures at all with a 180 lbs driver, I see no benefit to raising the minimum weight another 45 pounds.

For those not familiar with John's car, it is a Maloy/Phoenix, which is the heaviest single seat DSR design. While the cars have proved very safe, they are also quite stout, and IMO are not a good basis for comparison to a converted FC in F1K, so let's stick with considerations that apply to this concept.

John, if you wish to swap bodywork and throw some wings on that car, go for it!

Stan

[John]

Thanks Stan,

First I will get it all sorted out as a DSR, Perhaps I will look at a conversion a year or three, I will watch the F1000 with interest as I think they will be really super cars.

[Marshall Mauney]

While I am confident Sean could take some weight out of his car rather easily, trying to get down to that magical 900 lbs might well turn out to be an expensive proposition.

Stan, I'm not sure I agree. I have to add ballast to get my F500 up to 800 lbs, and it's not one of the lighter chassis designs. While I am fairly light (~150), I'm not THAT far below average for an open-wheel pilot. If I were to start with a F500 chassis and simply add a couple of wings and swap motors, I don't see a problem keeping the car below 725 or so w/o driver. Basically, that's assuming that the larger engine, wings and diff will add less than 100 lbs - probably a safe bet.

Remember that the bike mill and tranny will be far lighter than the existing drivetrain, and there's nothing you're adding to the car that's not already there in a FC.....except, of course, the SIR...... [You'll probably need less radiator area, too....hmmmm.....]

[John]

Actually you need more radiator and you need a big oil cooler. You get a 180hp bike motor hot and it will blow up, and they really hate hot oil. My FC was 144 at the crank, the DSR is around 180 at the rear gear so it is at least 50 more HP. More HP means (usually) more heat to dissapate. The radiator and cooler on my DSR are much bigger than the ones on my FC. Carnut 169 had to go to bigger side pods to cram his radiators into, from what I can see of his car.

[Stan Clayton]

Your point is well taken, Marshall, but I think you're comparing apples to oranges. A F500's WB is a foot or more shorter than the shortest FC, it has a narrower track, smaller rad, no diff, smaller fuel cell...and the list just goes on. And speaking of fuel cell, how big is the one in your car? Liter bike engines guzzle gas like a drunken sailor does cold beer, and the tiny cells in the F500's I've looked at don't look big enough.

Besides, with Sean's car we are talking about an actual, walking, talking F1000 that weighs 765-ish without driver or gas, so we KNOW what it will weigh. No guessing here. So my question is, do we want to stick with 900 lbs? I don't mind either way, but I would like to hear from more folks.

Marshall votes for 900 lbs, right?

Stan

Edit: corrected weight...

[Mike B]

[size=2]Marshall,[/size]

[size=2]You’ll also need larger wheels and tires (or larger stones…)[/size]
[size=2]In all this discussion, I keep mentally referring to Sean’s conversion as the best example. His conversion is exactly what I had in mind when I began my conversion and the F1000 website. I know he is leaning toward the 8 & 10” wheels and working on tunnels, both of which are fine in Stan’s proposal. Sean also hit 955-ish pounds without breaking a sweat so that is in the ballpark of a good minimum weight. I absolutely abhor adding ballast.[/size]
[size=2]Sean,[/size]
[size=2]Can you shed some light on your actual weights and what changes you could make (and the $) to reduce it?[/size]