New F600 rules proposal

[Marty Nygard]

Jay said "To allow the use of IRS & diffs in this class would add a minimum of $5k to the cost of a car."
I was originally skeptical so I checked my records for the costs associated with the rear suspension and drive for my latest hare brained scheme. I am the king of cheap and the cost for all parts (A arms, uprights, hubs, bearings, drive shafts diff and diff carrier) was $2410. The uprights are heavy steel fabrications from old pieces lying around the shop. Upgrading to uprights from the Pegasus catalog would add about $1100. This would result in $3510 and includes no labor cost or profit. So, I can see $5K for the cost of an independant rear.
I am curious about the equivalent cost of the live axle (axle + bearings + bearing carriers + radius rods and locating links)?
Marty

[nulrich]

I'm a bit confused about the rear axle. Can you suspend the rear axle completely using springs and dampers? Without a differential there are limits, but you could do a fairly sophisticated rear suspension and still meet the rules as written.

Are any of the potential tires radials? They will perform best with static negative camber, and I can imagine several ways of accomplishing that in the rear while meeting the letter of the rules. Might be worth considering more explicit prohibitions if that's the intent.

I don't think an independent rear suspension adds $5k to the cost of the car. Assuming a suspended rear axle, which has many of the same components as an independent rear, I come up with roughly $2-3k difference, especially since in a low cost car you would want to use many of the same components front and rear.

I guess the real question concerns the philosophy of the class, and whether you can come up with a set of rules that appeals to people coming out of karting, existing F500 competitors, and formula car "purists." Not sure it's possible.

Nathan

[Scootin159]

I am curious about the equivalent cost of the live axle (axle + bearings + bearing carriers + radius rods and locating links)?

$1314 - http://novakar.com/Suspension_4_link.pdf

-----------------------

With regards to the bodywork rules. If the intentions are to require flat sided sidepods, and a flat floor, then they do need to be revised (the F500 wording is signficantly insufficient IMHO). I don't think you want to mandate purely flat sides or tops to the sidepods (some sculpting is "free" and looks signficantly better).

Also - what is the difference between a front wing and a sports car nose that creates downforce? A wing is defined as something with a leading and trailing edge and creates downforce. A sports car nose obviously has a leading edge, but the trailing edge could be disputed. Now what if you tucked a diffuser under that sports car nose, but kept the top & bottom edges from "touching" in the rear - is this now a front wing?

[Jnovak]

Nathan, our cars use pushrods and rockers to operate the springs on our F500 car. The springs are located at the rear roll hoop bulkhead area and the system is quite functional. The longitudinal location is by trailing links. The lateral location on most cars is by a Panhard bar, Watts Link or a WOB link. Our cars uses our own design (Novalink). It is adjustable for RC height very easily.


The sidepods can be sculpted within the dimensional limits. The outside must be within 1" of the outside a line tangent to the outside of the tires. Vertical height must be between 9" and 12". There also cannot be gaps between the midsection and the pods (as in continuous). ALL FORWARD FACING OPENINGS in the bodywork MUST be used for cooling, thus side vents as in SR cars are NOT allowed unless all the air is used for cooling.

Obviously a Sports car nose leaves some opportunity for drag reduction and Df. Our cars have always had an SC nose. I think, of course, that we are doing our best to optimize the nose within the rules. Several championships have been won with SC noses but many more have been won with your typical formula car style nose. Our new car will be availabe with both.

Thanks for all your comments and suggestions. Jay Novak

[Marty Nygard]

Scootin,
The $1314 did not include axle itself, the sprocket carrier or (unless they are using splined wheels) the hubs.
I brief look through of a mini-sprint catalog makes it look more like $1500 but does not include pushrods or bellcranks.
Marty
BTW, after looking at the mini-sprint stuff, I might be inclined to use a beam front axle with mono shock for the ultimiate low cost front suspension.

[Jnovak]

Scootin,
The $1314 did not include axle itself, the sprocket carrier or (unless they are using splined wheels) the hubs.
I brief look through of a mini-sprint catalog makes it look more like $1500 but does not include pushrods or bellcranks.
Marty
BTW, after looking at the mini-sprint stuff, I might be inclined to use a beam front axle with mono shock for the ultimiate low cost front suspension.

Marty & others, that link is a very old link to Don Clar's old Novakar website. That kit was a simple 4 link kit that Don produced to update an old F500, that price is probably 10 years old. Don passed away a couple of months ago so right now his business is in limbo.

Our 50mm tubular axle kit with all bearings, bearing carriers, wheel hubs, sprocket adaptor, sprocket, brake rotor hub, brake rotor, caliper adaptor, 4 piston Wilwood powerlite caliper, brake pads etc was $1700 and we sold 5 of those kits to several different F6 conversions guys.

Not a bad price for that much stuff and WAY LESS than any independant suspension with a diff would cost. Also do not forget that you have to have a VERY different fram foe an independant suspension and this also adds lots of cost to the deal.

Thanks ... Jay novak

[Purple Frog]

So... i'm assuming you wouldn't want someone taking an old FF chassis and pluging in a 600cc bike motor, and adding the required bodywork. Because old rocker sliders can be had for next to nothing. That plan would make IRS relatively cheap.

[Daryl DeArman]

Personally, I like the idea of a live axle - less complicated, less cost. I do not mind the reference to karts. I am looking at this more as a grown up shifter kart which could accomodate my larger size. I don't need more complexity - I just want to drive. I view this class as more of a driver's class like FV. But the car will sound and look just so much better.

Well said. Worth repeating.

[Stumpthumper]

Personally, I like the idea of a live axle - less complicated, less cost. I do not mind the reference to karts. I am looking at this more as a grown up shifter kart which could accomodate my larger size. I don't need more complexity - I just want to drive. I view this class as more of a driver's class like FV. But the car will sound and look just so much better.

As a new guy who is very interested in this class, I completely agree. Costs should be the number one consideration, while achieving a much more modern looking car. I don't see the point of making essentially a FF or FB with a different engine. Also, ensuring the car is closer to an F500 will help the car run in the same rungroup and increase those numbers. More fun.

[R. Pare]

" A single 4 piston caliper may be used on a single rear brake rotor."

I assume that this is an allowance for, not a restriction to?

"The purpose of these rules is to minimize the use of “ground effects” to achieve aerodynamic downforce on the vehicle. Thus, for full width of the body between the front and rear axles, the lower surface (surface licked by the airstream) shall not exceed 2.54cm (1 inch) deviation from the horizontal in any longitudinal section through that surface. "

Re word this. Years ago I posed this question to the CRB ( the same wording was in FF and FC):

"If I have a series of surfaces, each stepped upwards from the adjacent panel by 1" or more, yet each individual panel is horizontal, please tell me where the "deviation from the horizontal" is."

They couldn't answer the question, and the wording got changed (poorly, unfortunately, and it took another 10 years before they would consider the rewrite that was passed 3 years ago)

And: what rewording have you put in that would disallow what you did a few years ago ( re-orient the engine) that caused the rules re-write after you won the protest and appeal?

Lastly, I would highly recommend that the floorpan be required to be a "stressed panel" for safety's sake.

[Marty Nygard]

Mr Frog,
Please define the "next to nothing" cost for an old rocker slider.
Anyway, how about this for a compromise. Allow converted IRS cars with a weight penalty (say 50#).

Mr Pare,
The "longitudinal section" rule in the current proposal is identical to the wording in the sports racer rules which now, according to the Jacek exception, mean anything but flat bottomed. I agree with nulrich that using the new FC language would be a better limit on the underbody aero.
What would you make your mandatory stressed floorpan from? Please say carbon!!

Marty

[lancer360]

A few people commented on the sound of a F600, so here is a clip Jay Novak took of me running on the front straight at Roebling Road in the rain and then a lap at Road Atlanta.

http://www.youtube.com/watch?v=-H0I-i0WKFM
http://www.youtube.com/watch?v=lgCkAxrPpBg

[Scootin159]

Chris,

You need to post more videos. While I can watch those videos all day long, I would certainly appreciate some more

[Jnovak]

Richard, please see my comments within your quote in red

" A single 4 piston caliper may be used on a single rear brake rotor."

I assume that this is an allowance for, not a restriction to? Correct

"The purpose of these rules is to minimize the use of “ground effects” to achieve aerodynamic downforce on the vehicle. Thus, for full width of the body between the front and rear axles, the lower surface (surface licked by the airstream) shall not exceed 2.54cm (1 inch) deviation from the horizontal in any longitudinal section through that surface. "

Re word this. Years ago I posed this question to the CRB ( the same wording was in FF and FC):

"If I have a series of surfaces, each stepped upwards from the adjacent panel by 1" or more, yet each individual panel is horizontal, please tell me where the "deviation from the horizontal" is."

They couldn't answer the question, and the wording got changed (poorly, unfortunately, and it took another 10 years before they would consider the rewrite that was passed 3 years ago) We are working on rewording this right now.

And: what rewording have you put in that would disallow what you did a few years ago ( re-orient the engine) that caused the rules re-write after you won the protest and appeal? The previous rule stated that the powertrain had to be derived from snomobile powertrains. There were plenty of snowmobiles with engines and transfer cases just the way our car was designed, That was why we were certain it was legal. After the protest at the Runoffs (we were legal) the CRB rewrote the rules to force the engine installation such that the exhaust ports must face forward. We re-did the car in a couple of months of work and won the Runoffs with the car in the following season. I never fought the rules change (I could have) as I felt that the chassis/aero package was good enough to win no matter what the engine orientation was. It was a very interesting experience to say the least. That was not the only time we had been protested at the Runoffs. We were always found to be legal every time.

Actually we have not addressed this in the F600 rule as I think there is not any advantage in turning the engine around in an MC engined car.

Lastly, I would highly recommend that the floorpan be required to be a "stressed panel" for safety's sake.

Good idea.

Thanks ... Jay Novak

[Jnovak]

A few people commented on the sound of a F600, so here is a clip Jay Novak took of me running on the front straight at Roebling Road in the rain and then a lap at Road Atlanta.

http://www.youtube.com/watch?v=-H0I-i0WKFM
http://www.youtube.com/watch?v=lgCkAxrPpBg

Very cool Chris, that was the 1st time I have seen the Road Atlanta video. Sweet.

Guys, you shold look at the front suspension and body movement. Not bad for a car with elastomer springs and no shocks.

Thanks ... Jay Novak

PS: The F600 record at Atlanta is a mid 1:30.? (the 1st race with Glenn Cooper in the NovaKar F6)

The new cars will be a bit quicker imho.

[R. Pare]

Just don't use the phrase "stressed panel" - just state that it is required to be fastened such and such.

The "longitudinal section" rule in the current proposal is identical to the wording in the sports racer rules which now, according to the Jacek exception, mean anything but flat bottomed.

That flaw in the wording was pointed out to them many, many years ago - it would allow 1" deep tunnels situated well above the floorpan if desired.

[lancer360]

Ok, here are some more videos.

Carolina Motorsports Park. http://www.youtube.com/watch?v=LzCSM7T3YFE

Clint McMahan drove my car at CMP and turned an unofficial 1:35.7s during a time trial event

Another external video by Jay taken at Roebling Road. http://www.youtube.com/watch?v=bCPnsNeqF78

[lancer360]

Just found the link for a external video Jay Stroud took of Clint, McMahan, Hank Bilek, Dan McMahan, and Bill Bradley running at VIR in March of this year. This is best audio I have heard yet for the F600's. There is one F500 in the mix, he is the car just behind Dan and I as I passed Dan.

http://www.youtube.com/watch?v=Lmzl-Bq_jm4

[Daryl DeArman]

Somebody contaminated that audio with the sound of a FV motor. Maybe clip the last 3 seconds...it would sound so much better


I'm not certain that there is any concern about packaging and the cylinder head orientation in a F600. However, if one of the big 4 come out with a F600 with rearward facing exhaust ports it should certainly be allowed, shouldn't it? Some have already done this with dirt bikes for a balance/weight distribution issue. I'd think packaging of the exhaust on a 4cyl. street bike with the required emissions and mufflers could prove problematic and something we may not see for a very long time.

[JerryH]

Jay,

This is going to be a great class! Thanks to you and the other members of the F600 committee for all you have done to make it possible.

The flat floor wording in FB and FF is slightly different and in my opinion better than
FC.....if the intent is a truely flat floor. Please take a look at them.

As far as shocks go......limit it to readily available off the shelf shocks.....and place a cap on retail price. Two way adjustable is the way to go.....but they can get expensive unless a price cap is specified. (What is the $500 shock you mentioned? I could use it on another project.)

Bodywork rules seem specific enough.....except for the outer wall of the sidepod.....which needs some more detail if the intent is that it be a vertical surface.

I will be building a car for the class!

Jerry Hodges

[Jnovak]

Somebody contaminated that audio with the sound of a FV motor. Maybe clip the last 3 seconds...it would sound so much better


I'm not certain that there is any concern about packaging and the cylinder head orientation in a F600. However, if one of the big 4 come out with a F600 with rearward facing exhaust ports it should certainly be allowed, shouldn't it? Some have already done this with dirt bikes for a balance/weight distribution issue. I'd think packaging of the exhaust on a 4cyl. street bike with the required emissions and mufflers could prove problematic and something we may not see for a very long time.

No problem as long as it is a production 600cc 4 cylinder engine. Remember they all have to run IIR (inlet restrictors)

Thanks ... Jay Novak

[nulrich]

An independent rear suspension will cost more than a solid rear axle, even a suspended one. We could quibble about how much, but a solid rear axle will reduce cost.

The handling of a car with a suspended solid rear axle is not much different from an independent rear suspension. The biggest difference stems from the solid rear drive axle. What about allowing an open differential but not an independent rear suspension? An open differential can be had for a few hundred dollars (including case and bearings) from a variety of sources. You don't need any of the higher cost limited slip options available for FB, nor tripod joints, uprights, and so on.

I've never driven an F500, but my (very limited) experience in karts suggests the driving style and setup is heavily influenced by the locked rear end. What do drivers who have driven both F500/F600 cars and formula cars with differentials say?

With an open differential and the other changes you've proposed, I could see this class become a true entry into the mainstream of formula car racing, rather than a divergent branch. Just my opinion.

Nathan

[Jnovak]

An independent rear suspension will cost more than a solid rear axle, even a suspended one. We could quibble about how much, but a solid rear axle will reduce cost.

The handling of a car with a suspended solid rear axle is not much different from an independent rear suspension. The biggest difference stems from the solid rear drive axle. What about allowing an open differential but not an independent rear suspension? An open differential can be had for a few hundred dollars (including case and bearings) from a variety of sources. You don't need any of the higher cost limited slip options available for FB, nor tripod joints, uprights, and so on.

I've never driven an F500, but my (very limited) experience in karts suggests the driving style and setup is heavily influenced by the locked rear end. What do drivers who have driven both F500/F600 cars and formula cars with differentials say?

With an open differential and the other changes you've proposed, I could see this class become a true entry into the mainstream of formula car racing, rather than a divergent branch. Just my opinion.

Nathan

Most F500s (solid axles) do handle like a kart in that you have to pitch them into the corners. Our car is not that way. It tunes & handles like any nice formula car.

Thanks ... Jay Novak

[R. Pare]

The flat floor wording in FB and FF is slightly different and in my opinion better than
FC.....if the intent is a truely flat floor.

Ummmm.... the wording for FC IS the wording for FF (and FB stole from the FF rules).

[Bill Bonow]

Was it envisioned to convert an FF, cut off the back half and replace with 600 and solid axle (ala FC to FB) ?

[lancer360]

I had been thinking the same thing. I think it would come down to whether or not you could make it fit the necessary dimension for width and wheel base and still package the engine cleanly. Something tells me the 600 engine and rear axle package could be made to fit. Then it would only require adding the side pods which shouldn't be too difficult.

[Purple Frog]

To answer Marty: Yes i know of "sliders"* in the CFC mode (87-90 Reynards and 93-95 VD) being marketed in the $3K price range.

No, I am not telling where. I'm trying to buy them. But I can't afford all of them.

* no engine, no gearbox, everything else in place

[Ananth K]

Was it envisioned to convert an FF, cut off the back half and replace with 600 and solid axle (ala FC to FB) ?

I had a talk with Jay regarding this. Apparently, almost no FF can meet the max. overall width rule of 60", even the oldest ones. So to convert an older FF you would also have to make new control arms, pushrods and tierods in addition to F500 type bodywork and rear suspension.

[Purple Frog]

What is going to be the legal rim sizes for this F600? Murphy had told me at the ARRC that it may be 13" to open up more diverse tire choices in terms of manufacturer, size, and compound.

[nulrich]

Max width for FF/FC is 185 cm, or just under 73 inches, so narrowing it to 60 inches would require lots of new parts.

The wheelbase of the latest Van Diemen is 2575 mm, or just over 101 inches, which is 11 inches longer than the max wheelbase allowed in these proposed rules. I'm sure the motorcycle drivetrain will allow a much shorter wheelbase, but not sure how much shorter.

My first guess is I would want the weight distribution to be much further forward on one of these cars, especially since you can run the same size tires front and rear. Anyone want to share typical front/rear split on an F600?

Jay, I'm curious how you overcame the inherent tendencies of a locked rear axle, but I'd understand if you don't want to share your secrets! From a purely theoretical standpoint, you have to sacrifice overall grip to achieve balance with a solid rear axle. In practical terms I don't know just how much time you'd gain by adding an open diff, it may not be that significant on one of these cars.

Someone mentioned it earlier, but I wonder how far these rules are from the current FSAE rules?

Nathan

[GBugg]

What do drivers who have driven both F500/F600 cars and formula cars with differentials say?


Nathan

Nathan - I've driven FC (MC powered before it was cool), DSR, F440, F500, and now F600. They all drive differently. The live axle cars can be very forgiving and are very easy to drive. Personally, I would not be in favor of adding a diff. It just isn't necessary and it is an additional cost.

I'm ready to nail the rules down and get to prepping for next season!!

BTW - Sir Frog, 13x7 wheels are proposed as options.

[Marshall Mauney]

I've never driven an F500, but my (very limited) experience in karts suggests the driving style and setup is heavily influenced by the locked rear end. What do drivers who have driven both F500/F600 cars and formula cars with differentials say?

I've driven both (karts, FF, F500, FE), and I frankly like the live axle handling. It requires a more aggressive driving style, though, so it's not for everyone.

[Jnovak]

Max width for FF/FC is 185 cm, or just under 73 inches, so narrowing it to 60 inches would require lots of new parts.

The wheelbase of the latest Van Diemen is 2575 mm, or just over 101 inches, which is 11 inches longer than the max wheelbase allowed in these proposed rules. I'm sure the motorcycle drivetrain will allow a much shorter wheelbase, but not sure how much shorter.

My first guess is I would want the weight distribution to be much further forward on one of these cars, especially since you can run the same size tires front and rear. Anyone want to share typical front/rear split on an F600?

Jay, I'm curious how you overcame the inherent tendencies of a locked rear axle, but I'd understand if you don't want to share your secrets! From a purely theoretical standpoint, you have to sacrifice overall grip to achieve balance with a solid rear axle. In practical terms I don't know just how much time you'd gain by adding an open diff, it may not be that significant on one of these cars.

Someone mentioned it earlier, but I wonder how far these rules are from the current FSAE rules?

Nathan

Our F500 car that won the Runoffs with Brian driving typically generates 2 to 2.2 Gs lat accel every time he gets into a corner. An FF National Champion who has raced against Brian in Nationals and has never beaten him told me that he has never seen any car go through turn 1 at Grattan faster (Brian loves Grattan). He told me that he tried to stay with Brian but there was no way it could be done. Live axles can be made to work really well. The only place an FF is faster than our car is at very fast tracks like Road America. On the short tracks the FF cars could not beat that car driver combination. Wish I had not sold it. The weight distribution on that car was 48F/52R with driver and weighed 806 lbs after winning the Runoffs.

The FSAE rules are MUCH different.

Thanks ... Jay

[Purple Frog]

All over the country in garages are those 12+ year old AMAC DSRs that were put to pasture with the introduction of the Stohr. They are probably narrow enough, and short enough, and have solid live axles already set up for m/c power. Maybe they can be retrofitted.

[Stan Clayton]

Max width for FF/FC is 185 cm, or just under 73 inches, so narrowing it to 60 inches would require lots of new parts.

That's why I wrote to the committee to suggest allowing 65" overall width...it could potentially capture those older FF's too new for CFF and too old to be competitive against newer designs. I also suggested a longer max wheelbase to capture some of those cars, but got nowhere with over 90".

All over the country in garages are those 12+ year old AMAC DSRs that were put to pasture with the introduction of the Stohr. They are probably narrow enough, and short enough, and have solid live axles already set up for m/c power. Maybe they can be retrofitted.

Mike, AMACs have solid IRS rear ends...not live axles. They're still driven like a kart, but AFAIK none of them came with live axles.

[starkejt]

What is a solid IRS rear end? (serious question)

[Scootin159]

What is a solid IRS rear end? (serious question)

Basically picture a normal IRS with a spool instead of a differential.

[starkejt]

OIC

[Stan Clayton]

Basically picture a normal IRS with a spool instead of a differential.

Correct, and it's very, very cheap. Can't be significantly more than the live axle setups referenced above. There is a photo showing the rear setup on this AMAC webpage. Basically, one welds a spacer to the two inner races of VW CVs and mounts them in a bearing carrier. Art McCreary (hence A-MAC) still makes and sells them.

Oh, and it typically bolts right up in place of a Mk 8/9.

The contact number for Art on the AMAC mainpage is, I suspect, no longer correct, as he moved from to southern Oregon several years ago.

[Marty Nygard]

I ran a spool in my homebuilt DSR. Primarily because I came from the Prod car ranks where most cars had locked rear ends. It had a certain amount of corner entry understeer but was manageable if you pitched it a little.
There are a few DSRs running VW open differentials; with enough downforce and traction, it is difficult to make the inside wheel spin.
Marty