Performance target for F500

[Jnovak]

Question for the entire F500 community.


What engine package be the performance target for F500?


1. 494 - 493 Rotax 500 cc 2 stroke
2. 593 Rotax 600 cc 2 stroke


This is an honest question and is only intended to try to get a representative opinion from the F500 community.


Changing my vote to #2 because i like faster rather than slower

[holmberg]

I've never owned an F500, and have no opinion about target power, but I am curious what about the chassis rules is insufficient for the speeds these cars are reaching? I just want to educate myself about what is needed in a chassis design to be safe at this speed. For example, are the FF rules sufficient at this same speed? I'm aware of the chassis differences between F500 and FF, but which aspects specifically are the SCCA decision-makers concerned with?

[Jnovak]

I've never owned an F500, and have no opinion about target power, but I am curious what about the chassis rules is insufficient for the speeds these cars are reaching? I just want to educate myself about what is needed in a chassis design to be safe at this speed. For example, are the FF rules sufficient at this same speed? I'm aware of the chassis differences between F500 and FF, but which aspects specifically are the SCCA decision-makers concerned with?

mostly top end. Personally I do not think they are too fast, but our car went 159 mph at Daytona and that got people excited.

You simply cannot go faster for less $$$ about 1/3 the cost of a top FF but faster.

Check out this video, about a page down.

https://m.facebook.com/sccaofficial/

[reidhazelton]

Slower than an FF would be nice.

[Jnovak]

Slower than an FF would be nice.

why not faster and way less cost??

[reidhazelton]

why not faster and way less cost??

Just teasin' ya my man. Us FF guys don't like getting beat by cars that cost half of a used FF. It's bad for the ego.

[clint]

mostly top end. Personally I do not think they are too fast, but our car went 159 mph at Daytona and that got people excited.

You simply cannot go faster for less $$$ about 1/3 the cost of a top FF but faster.

Check out this video, about a page down.

https://m.facebook.com/sccaofficial/

If top speed is the concern here what top end would be deemed safe? What criteria would be taken into consideration for this determination? Is there a specific incident that has received attention that hasn't been public news that's sparking this? I'm not agreeing or disagreeing that they're too fast or safe at the top speeds we reach I'm just asking for some ground floor questions to be answered before the Circus starts.

[TDI PILOT]

My opinion is to make the standard performance target the current configuration Rotax 593, without inlet restrictors at 875 lbs. My reasons are as follows

1. Making the dominant engines in the class (593 and 4-cycle engines) the same weight will make things easier when it comes to balancing power using the methods the SCCA is currently using...GPS based acceleration up to 100 mph. This will also level the playing field for lateral grip and braking between all the platforms.

2. There are plenty of 493/494 powered cars still competing, so give them the ability to run dual exhaust pipes to bring their power level up to the 593/MC standard, while keeping their minimum weight the same as the rest of the class...875 lbs.

3. Making min weight the same for all the cars will motivate some of the bigger drivers that are currently unable to make min weight to stay in the class and/or start racing again. This will effectively get them back into owning an extremely competitive car for very little cost (new exhaust for 494/493).

-Eric

[Raceworks]

Just teasin' ya my man. Us FF guys don't like getting beat by cars that cost half of a used FF. It's bad for the ego.

The problem is except for 2 or 3 individuals most of F5's are only faster in a straight line, then they become very erratic rolling chicanes in a corner. Even the fast guys are hard to gap properly in a mixed field because the lack of any suspension means they tend to do things mid-corner that can catch you off-guard in an FF.

[Raceworks]

If top speed is the concern here what top end would be deemed safe? What criteria would be taken into consideration for this determination? Is there a specific incident that has received attention that hasn't been public news that's sparking this? I'm not agreeing or disagreeing that they're too fast or safe at the top speeds we reach I'm just asking for some ground floor questions to be answered before the Circus starts.

It's top speed versus a combination of the integrity of the driver "safety cell" are of the chassis and how much disposable (impact-attenuation) structures. You've got to plan for the worst possible combo of events: at Daytona say you had a suspension failure that put you straight into the wall on the front straight at 155mph.

When the rulebook was first created the cars were a lot slower (back when it was "Formula 440"). I don't know how much it's been revised since as far as tubing thickness and front crush structures.

[Raceworks]

why not faster and way less cost??

Well, technically a shifter kart is faster than either F5 or FF, and costs less than either one....

[TDI PILOT]

The problem is except for 2 or 3 individuals most of F5's are only faster in a straight line, then they become very erratic rolling chicanes in a corner. Even the fast guys are hard to gap properly in a mixed field because the lack of any suspension means they tend to do things mid-corner that can catch you off-guard in an FF.

What do you mean by “they do things mid-corner that can catch you off guard”?

A F5 has about the same suspension travel as a FF, (~2.5”), but the live rear axle requires some rear slip angle to carry as much momentum as possible.

[TDI PILOT]

Well, technically a shifter kart is faster than either F5 or FF, and costs less than either one....

Which SCCA formula car class are shifter karts allowed in?

[Jnovak]

It's top speed versus a combination of the integrity of the driver "safety cell" are of the chassis and how much disposable (impact-attenuation) structures. You've got to plan for the worst possible combo of events: at Daytona say you had a suspension failure that put you straight into the wall on the front straight at 155mph.

When the rulebook was first created the cars were a lot slower (back when it was "Formula 440"). I don't know how much it's been revised since as far as tubing thickness and front crush structures.

i think that the large majority of F5 cars are actually as safe or safer than the majority othrt formula cars. For example every F5 has full side pods that absorbe LOTS of energy in a crash. The same goes for F5 cars with sports car noses, essentially no wheel entanglment ever,

Here are some other examples that are in many F5 cars including ours which has a structural carbon front crush box and every other F5 has the required aluminum crush box.

Most of the cars now have wide cockpits with LOTS of padding as well as major structural protection. Come and check out one of our cars and see for yourself.

[tfriest]

I've never owned an F500, and have no opinion about target power, but I am curious what about the chassis rules is insufficient for the speeds these cars are reaching? I just want to educate myself about what is needed in a chassis design to be safe at this speed. For example, are the FF rules sufficient at this same speed? I'm aware of the chassis differences between F500 and FF, but which aspects specifically are the SCCA decision-makers concerned with?

Most F500s have thinner walled roll hoops/cages/bracing because the rules allow for it (I think there is a specific exemption for cars up to 875 pounds allowing for thinner tubes). The cars are also "small" compared to almost every other SCCA class, which leads to the thought they don't have as much crumple zones in a crash.

There is still a stigma from the old (1980s) no-suspension days too, but even with the suspension on a kbs mk7/invader, I doubt my car has as much suspension travel as an FF.

All that combines for a perception that F500s shouldn't be going 150+ mph.

I suspect unrestricted 593 or MC engines would be noticeably faster. That would probably move the cars in the wrong direction speed wise, even though it'd be a lot nicer to run unrestricted for engine performance/life reasons.

I like a quick and nimble car where raw speed isn't the main factor, so having cars that run in the 130 mph range but can corner as well as, or better than, anything else (non-winged) is a great feature.

All that being said, I wouldn't want SCCA to try to slow the cars down a lot, but a small slowdown or keeping it the same would be fine with me. I definitely don't see a need to change things so we go even faster.

[Jnovak]

Most F500s have thinner walled roll hoops/cages/bracing because the rules allow for it (I think there is a specific exemption for cars up to 875 pounds allowing for thinner tubes). The cars are also "small" compared to almost every other SCCA class, which leads to the thought they don't have as much crumple zones in a crash.

There is still a stigma from the old (1980s) no-suspension days too, but even with the suspension on a kbs mk7/invader, I doubt my car has as much suspension travel as an FF.

All that combines for a perception that F500s shouldn't be going 150+ mph.

I suspect unrestricted 593 or MC engines would be noticeably faster. That would probably move the cars in the wrong direction speed wise, even though it'd be a lot nicer to run unrestricted for engine performance/life reasons.

I like a quick and nimble car where raw speed isn't the main factor, so having cars that run in the 130 mph range but can corner as well as, or better than, anything else (non-winged) is a great feature.

All that being said, I wouldn't want SCCA to try to slow the cars down a lot, but a small slowdown or keeping it the same would be fine with me. I definitely don't see a need to change things so we go even faster.

the only wsy to slow the cars down is smaller restrictors to th 593 and the mc powered cars. If there are smaller restrictors then the importance of the clutching become much more importtant than it already is. The only real problem with the MC engines is that they pretty much always run RIGHT with no adjustments required other than changing the final drive ratio for track lenght/speed

I kind of like the idea of the 593 being the HP target and allowing the 494 and the 493 engines to use twin pipes and any production bits thar are available. The downside of this is clutch tuning which, i think, is much easier to do now.

[Rick Eskola]

How about this for a scenario.

No restrictors for the 593 or MC engines @ 900 lbs. Allow current FF wheel and tires (harder compound skinnys all the way around).

My reasons

(1) No restrictors eliminates many trips to the dyno trying to work around the restrictors or doing fuel tunes for constant restrictor changes.

(2) FF wheels and tires. Allows for bigger brakes (safety) and harder skinny compound tire would slow cars in corners.
Tires and wheels are available now.

(3) 900# could slow acceleration and maybe top speed. ( I think weight wise,this is far as we can go with current suspension.)
Our cars would be lighter than FF, tires could last longer.

As for the 494/493
You could allow twin pipes but it would be costly to develop for an engine that is on the way out, not to mention, peaky to clutch.
Not sure what to do with these engines.

I know this scenario is pretty vague, and would need tweaking, but could be very cost effective in the future.

This is just my thoughts

Thanks

Rick

[tfriest]

How about this for a scenario.

No restrictors for the 593 or MC engines @ 900 lbs. Allow current FF wheel and tires (harder compound skinnys all the way around).

My reasons

(1) No restrictors eliminates many trips to the dyno trying to work around the restrictors or doing fuel tunes for constant restrictor changes.

(2) FF wheels and tires. Allows for bigger brakes (safety) and harder skinny compound tire would slow cars in corners.
Tires and wheels are available now.

(3) 900# could slow acceleration and maybe top speed. ( I think weight wise,this is far as we can go with current suspension.)
Our cars would be lighter than FF, tires could last longer.

As for the 494/493
You could allow twin pipes but it would be costly to develop for an engine that is on the way out, not to mention, peaky to clutch.
Not sure what to do with these engines.

I know this scenario is pretty vague, and would need tweaking, but could be very cost effective in the future.

This is just my thoughts

Thanks

Rick

you can't raise the weight above 875 without rebuilding the frames of most cars or getting SCCA to increase the max weight for the tube size/thickness/material most cars use.

[Jnovak]

Most F500s have thinner walled roll hoops/cages/bracing because the rules allow for it (I think there is a specific exemption for cars up to 875 pounds allowing for thinner tubes.

actually not true that they are not safer.

In fact up to a year ago the rules, for roll bars, were exactly the same for all open wheel classes. Then 1 manufacturer made some cars with lighter wall tubing. Then to prevent these cars from having to cut their chassis apart, Jack Walbran commissioned a licensed PE ( Proffesional Engineer ) to do a stress analysis of the lighter roll bar and it passed the Structural Requirements required by the SCCA GCR. If you read the rules completely you will find that there is a section of the rules that allows for these alternative dimensions. Thus the recent adjustment to the rules.

[R. Pare]

Jay:

Curiosity - where in the rules is that exception? I cannot find it so far in the Feb. 2018 GCR.

[Jnovak]

Look in the gcr it is in the F500 rule. Or are you refering to the section that slloes PEs to check the stresses. That is also in the gcr.

[R. Pare]

You sure about this, Jay?

This is all that i can find in the GCR:

F500 section:

"8. Roll Cage
Cars shall have a full roll cage complying with section 9.4, made of steel, designed so that when viewed from
overhead, an opening, having a minimum width of fourteen (14) inches and a minimum length of seventeen
(17) inches is available for driver extraction under emergency conditions."

From 9.4.5:

"F. Exceptions for Formula Cars and Sports Racing cars

Any roll hoop design which does not comply with the specifications in 9.4.5, will only be considered
if it is accompanied by engineering specifications signed by a registered engineer stating that the
design meets the stress loading requirements below. No alternate roll hoop will be considered unless
it contains a main hoop having a minimum tubing size of 1.375” x .080” wall thickness. The roll bar
must be capable of withstanding the following stress loading applied simultaneously to the top of the
roll bar: 1.5 (X) laterally, 5.5 (X) longitudinally in both the fore and aft directions, and 7.5 (X) vertically,
where (X) = the minimum weight of the car.

No where that I can see states any exception for F500 main hoops. There IS, however, an exception for F500 cars weighing less than 875 pounds for thinner wall braces, but no exceptions that I can find for the main hoop.

Did something get dropped out of the 2108 GCR?

Another question: The F500 chassis rules above refer to 9.4, which is for Production and GT cars, neither of which the F500 is. I believe the rule should reference 9.4.5 instead. Overlooked misprint?

You might want to look into this to see if something was inadvertently dropped in the new GCR.

[Jnovak]

Richard, i believe that you are correct. The allowance is only for the forward facing braces and not for the roll bars.

Thanks very much for correcting this!

[Campbell Motorsport]

In the 80’s and early 90’s you could use 1.250 OD tube for roll hoops if the weight was under 825, without driver. There were several FV, F440, and DSR cars built to that rule. SCCA was not interested in “grandfathering” any of those bars under 1.375 OD- except the DB-1 front hoop. I replaced several 1.250 front and rear roll bars.

Larry Campbell

[Jnovak]

In the 80’s and early 90’s you could use 1.250 OD tube for roll hoops if the weight was under 825, without driver. There were several FV, F440, and DSR cars built to that rule. SCCA was not interested in “grandfathering” any of those bars under 1.375 OD- except the DB-1 front hoop. I replaced several 1.250 front and rear roll bars.

Larry Campbell

your correct Larry, those cars are no longer legaal to race.

[tfriest]

Okay, even if "most" cars can go heavier, I personally still prefer a lighter/nimbler race car that can stop/corner faster and I don't care as much about raw straight line speed. Having a lighter car also makes it easier to work on and transport (we have a homemade stacker in our trailer to be able to put 2 cars in).

F500s have a pretty good power/weight ratio now, so giving them more power and then more weight to counter the more power seems pointless.

One of the issues we have now is that the motorcycle engine cars are faster in a straight line but slower in the corners. This gives them similar lap times (depending on how straight or twisty the track is) but makes them hard to pass in the 2-cycle cars.

I'd like to see the class progress in other areas before upping the anti on horse power. Things like allowing a shock package to improve handling or fuel injection for the 2-stroke engines.

[Leon Mitchell]

The bigger picture here is getting people to race - car count. unfortunately due to people spending more time on here bitching, whining about EVERYTHING!!!!! , AND NOT PARTICIPATING, we may not have a class to bitch about. People are trying to make improvements and incentives to get participation up ( example - Jeremy Swank has made a attempt to encourage people in our class to race for a very large payout, regardless or which powertrain you use. Also its not just the payout, its a chance for this class to possibly take a step forward in everyone competing and enjoying the lost camaraderie this class once had.) There are hard feelings and certain people seem to want to be butt hurt over anything! There are a few people who are on here constantly attempting to make themselves look like they have ALL answers with - ALL THE OPINIONS, CREDENTIALS, DATA STATISTICS, AREO DYNAMIST FRIENDS, AND COLLEGES, AND NASA DATA!!!!!! These are the people who don't race, and always have excusses on why they don't race, blame others for why they don't race, and are constantly trying to finding flaws with the cars..., people, rules. This is the best bang for your buck class in SCCA, and for the most part some of the best people. This sight does offer good, positive things. Such as very useful info, and I have to say thank you to those who have spent allot of time and effort into sharing this info. No, not everyone will get along, or agree on everything, but we should be able to respectfully disagree and not make it personal. Certain people find it necessary to insult, and belittle people, that is the very negative part of all web sights. At the end of the day this is a lower budget class, not F!, yes some have more than others, but thats racing. Always has been, always will be. But I have also seen that the ones who HAVE MORE, also help others ALLOT!!! These few are always willing to share tires, parts, labor, or a cold beer, and or share a meal!! Thats the way is should be at the end of the day! For those of you who race hard, put in the effort, are as competitive as possible, and at the end of the day enjoy each others company, I commend you,I thank you, and hope to see you soon. Thanks Leon Mitchell

[GAC]

Question for the entire F500 community.


What engine package be the performance target for F500?


1. 494 - 493 Rotax 500 cc 2 stroke
2. 593 Rotax 600 cc 2 stroke


The opinion of many SCCA decision makers is that the F500 cars are getting too fast for the current chassis rules.


This is an honest question and is only intended to try to get a representative opinion from the F500 community.


Changing my vote to #2 because i like faster rather than slower

I vote for #1. Keep the costs down

[Jnovak]

I vote for #1. Keep the costs down

the 494 engine has been out of production for nearly 20 years and it is getting much harder to get parts.