SCCA: 600cc MC drivetrain in F500 car proposal

[Jim Murphy]

I am a new forum member and a SCCA F500 car owner/driver. I am posting here to let your forum know about what we are doing with 600cc motorcycle drivetrains. We have formed a committee headed by Jay Novak (some of you may know him as he has worked your national competition over the years)to evaluate the replacement of snowmobile two stroke/CVT clutches drivetrain with a stock 600cc MC drivetrain in F500 cars with no other modifications other than what is needed for drivetrain reliability. We are looking at this as an alternative (not a replacement) drivetrain for the following reasons:
1. EPA is tightening the emission requirements on 2 strokes and 2 strokes will disappear in the future from snowmobiles.
2. The cost of a 600cc MC drivetrain is now much lower than a 2 stroke snowmobile engine.
3. Many road racers are biased against 2 strokes and CVT clutches and a MC drivetrain is hoped to increase car entries.
We will be running several races around the country this coming season for evaluation purposes and input into the MC proposal with hopes of it being approved to begin in 2010.
You can see more about the proposal and all the discussions around it along with first photos from Jay's shop at www.eformulacarnews.com - go to forums and then scroll down to the F500 area.
For those of you not familiar with F500 - it is a BUDGET formula car road racing class where several components were replaced with much lower cost alternatives in order to bring the cost of a complete new car down to the low $20K.
I think that many of you who are interested in road racing after you graduate might hopefully be interested in the F500 class as an affordable way to road race.
We hope to meet and get to know many of you in the future.

8-11-09 Update: The SCCA Club Racing Board has received a majority positive inputs about this proposal. The next step is to gather track data and dyno data so that the correct size IIR can be determined. Once this has been accomplished the ruleset will be sent to the Board of Directors for a vote.

Jim Murphy
Been messing with these cars since 1982

[Jim Murphy]

Here is the finalized ruleset proposal that has been sent to the CRB; SCCA members, please send in your input to the CRB as soon as possible:

Hi everyone. After a ton of discussion within our MC engine proposal committee as well as much discussion with several engine builders, we have finalized our proposal that we will send to the CRB very soon.

We are posting our proposal here and on Apex Speed to get feedback from those who are interested in the subject. Please read the entire post. We welcome your comments and suggestions.

You will note that the committee has unanimously agreed on every aspect of this proposal. There are several VERY KEY elements within our proposal that we hope will convince everyone that our intentions are to make F500 a better class with more opportunity for growth in the future and that we are absolutely serious about parity between the 2 stroke and the 4 stroke engines.

The major change to our rules porposal is that current and future 600cc MC engines will be restricted by the use of an Individual Inlet Restrictor (IIR) between the inlet manifold and the cylinder head at each inlet port. This will assure that there will be parity between the various engines used in F500. This part of the rules is the result of extensive discussions between members of the committee, several engine builders and members of the CRB.

Another change to our rules proposal has been to allow the use of aftermarket ECU tuning modules. This is because they will be needed to properly tune the fuel map as a result of the use of the Individual Inlet Restrictors.

To: SCCA CRB members

Subject: A proposal to allow the use of 600cc motorcycle engines in Formula 500.

From: The F500 motorcycle engine committee.
Committee members
George Dean
Chris Huskamp
Clint McMahan
Dan McMahan
Leon Mitchell
Jim Murphy
Jay Novak
Jack Walbran

Statement of Purpose:
· To allow the use of stock production 600cc motorcycle engines for use as ALTERNATIVE ADDITIONAL engines for use in Formula 500.

· It is the intent of this rules proposal that the current F500 Rotax 493 and non RAVE 494 2 stroke engines remain the competitive benchmark for competition adjustments to F500 when 4 stroke motorcycle engines are allowed into use in F500. To that end all motorcycle engines allowed into F500 for use, as alternate engines in F500, shall be restricted by the placement of a defined restrictor between each cylinder throttle body and each inlet port. This restrictor will be used to initially restrict the horsepower of all motorcycle engines to a TBD HP level and to limit future growth of the maximum HP of these engines. The initial size and shape of the defined restrictor shall be determined by dynamometer and track testing of a representative engine or engines. The restrictor size will be adjusted by the CRB over a period of approximately three years in order to achieve and then maintain competitive parity between the 2 stroke Rotax engines and the 4 stroke motorcycle engines.

Background:
As many of you are aware several members of the Formula 500 community have formed a 600cc engine rules committee to try to define a working set of rules for the use of 600cc 4 stroke motorcycle engines for use within the F500 class. We have essentially used the engine rules for FB (F1000) with several additional requirements to control engine costs and performance.

F500, while a popular formula car class, has a relatively limited appeal to the greater formula racecar community due to many factors. These factors are concerns for many of the potential competitors in F500.
1. The 2 stroke engine and it's associated sound
2. Questions concerning the long term viability of the 2 stroke engine
3. No access to new 2 stroke engines
4. Limited access to used 2 stroke engines
5. The CVT transmission and its associated tuning challenges, which can be a significant barrier to entry, for new competitors.
6. No shifting due to the use of the CVT transmission

It is very interesting that the fastest F500 cars are now as fast as the fastest F-Fords at about 1/3 the cost of a new F-Ford. You would think that this would provide for one of the most popular formula classes in the SCCA. The reality is that F500 is presently the LEAST POPULAR formula class in the SCCA and has been close to the edge of National Status several times.

Class Rank, Class, National entries (2008)

3, FV, 581
4, FF, 430
7, FE, 353
8, FC, 337
10, FM, 316
11, FA, 295
13, F5, 276

Some competitors believe that access to snowmobile engines is a key element in the limited growth of F500. One of the reasons for this may be the relatively limited sale of snowmobiles across the US. For example:
1. In 2007 there were 1.12 million motorcycles sold in the US
2. In 2007 there were 79,815 snowmobiles sold in the US.
3. That is a Ratio of over 14 to 1 for total motorcycle to snowmobile sales
4. The estimate for the sales ratio of 600cc motorcycles to 500cc snowmobiles is at least 40 to 1 (from dealer estimates of sales)
5. Snowmobiles are sold ONLY in northern states and this dramatically limits their availability in other parts of the country.
6. There is NO QUESTION that there is concern about 2 strokes being legislated out of existence. Yes, there are companies that are continuing to build 2 stroke engines but the vast majority of manufacturers are now switching to much larger displacement 4 stroke engines, further restricting the future availability of 2 stroke engines.

New, younger, competitors that we want to race in our class are not coming to F500. Direct comments are that they want “racecars that shift”. and they “do not want to work on the clutches and maintain 2 stroke engines”.

The 600cc engine committee is confident that if 600cc motorcycle engines are approved for use as alternative engines to 2 strokes in F500, the growth of the class will be significant. When the first F500 car with a 600cc motorcycle engine was shown at the ARRC at Atlanta for show and tell, the car was BURIED BY INTEREST. At least 200 people were seriously interested in the project and the potential of the class. 2 former National Champions from other formula classes indicated that they would switch to this class if the bike engines were allowed. Numerous competitors offered deposits on the purchase of F500 cars with motorcycle engines. The interest level was amazing to say the least.

After posting pictures of this chassis with the 600cc motorcycle engine on ApexSpeed, there have been over 10,000 views on ApexSpeed on the subjects of these engines for use in F500. The best part of all in this interest is that the VAST MAJORITY are from people who are not now involved in F500 but could certainly become new competitors. Please see this link to the many posts on the subject.

http://www.apexspeed.com/forums/forumdisplay.php?f=91


Again, the committee is confident that we can make the 4 strokes and the 2 strokes competitive. They have about the same HP and about the same weight, so if the cars are competitively balanced, you can race a 2 stroke if you want or you can race a 4 stroke if that is your interest.

Also note that our efforts are intended to make CERTAIN that current F500 cars remain absolutely competitive and that the class philosophy of the absolute best value in low cost racing is maintained or even improved.

We have based our proposed engine rules on the current F1000 (FB) rules drawn directly from the 2008 GCR. If this proposal is approved the engine rules set would be integrated into the existing Formula 500 rules.

Proposed 600cc engine rules, this is a draft proposal and is open to changes as appropriate.

E.15. Alternative Motorcycle Engines
A. Mass produced (Honda, Kawasaki, Suzuki or Yamaha) water-cooled, 4 cylinder, 4-cycle motorcycle engines up to 600cc. The list of approved manufacturers may be modified by the CRB.

B. The current F500 Rotax 493 and non RAVE 494 2 stroke engines shall be the competitive benchmark for competition adjustments to F500 when 4 stroke motorcycle engines are allowed into use in F500. To that end all motorcycle engines allowed into F500 for use, as alternate engines shall be restricted by the placement of a defined restrictor between each cylinder throttle body and each inlet port. This restrictor will be used to restrict the horsepower of all motorcycle engines to a maximum TBD HP level. The initial size and shape of the defined restrictor shall be determined by dynamometer and track testing of a representative engine or engines. The restrictor size will be adjusted by the CRB over a period of approximately three years in order to achieve and then maintain competitive parity between the 2 stroke Rotax engines and the 4 stroke motorcycle engines. (see E.15.O for additional information)

C. All engine internals and compression ratio must remain stock. The competitor must present, on demand, an original factory manual for the engine to allow compliance verification. There shall be no modifications of any component of the engine unless specifically authorized in these rules.

D. The stock ECU shall be used. The ECU fuel map may be changed. Devices that modify inputs to the ECU (e.g., Power Commander) may be used. Stand-alone after market ECUs are not permitted.

E. Turbochargers and superchargers are prohibited.

F. Carburetion or fuel injection may be used. Fuel injection if used must be stock and unmodified for the model and year of the engine that is used.

G. The exhaust system and exhaust manifold are unrestricted, within SCCA safety regulations, except that stepped exhaust headers are not allowed.

H. The lubrication system is unrestricted except that dry sump systems are not permitted; any oil pan and/or baffling are permitted and the use of Accusump or similar oiling assist systems is allowed.

I. Oil coolers are unrestricted.

J. The cooling system is unrestricted. Radiators and associated ductwork shall comply with the existing F500 bodywork rules.

K. Replacement of the stock camshaft chain tensioner with any other chain tensioner is allowed. The replacement chain tensioner must attach directly to the engine in the original chain tensioner position. There shall be no modifications to the engine to enable the use of the replacement chain tensioner.

L. Replacement of the standard connecting rod fasteners with alternate fasteners is allowed as long as there are no modifications to the production connecting rods. Replacement of other nuts, bolts, fasteners, and washers with common hardware items performing only the same fastening/fitting functions also is permitted as long as there are no modifications to the production parts being assembled or the production assembly.

M. The engine head gasket must be the thickness of the OEM gasket for the year and model of the engine.

N. Camshafts and camshaft drive mechanisms cannot be modified or adjusted in any way unless specifically authorized in these rules.

O. The air inlet system shall have a restrictor placed between the intake manifold and the cylinder head for each cylinder intake port. This restrictor shall be made of .250” thick aluminum plate and shall have a maximum ID of XXX mm. The inlet side of the restrictors may be radiused to a maximum depth of .125”. The CRB may require adjustments to the maximum diameter of the restrictor at any time by publishing the requirements in FasTrack

P. Self-starter: Cars shall be equipped with an on-board self-starter and an on-board power supply controlled by the driver while in a normal driving position.

E.6. Transmission and Final Drive for motorcycle engines
A. Rear wheel drive only is permitted.

B. The final drive ratio is unrestricted. Internal transmission gears shall remain stock.

C. Engines must use the sequentially shifted motorcycle transmission as supplied with the engine. Reverse gear is not required.

D. All gear changes must be initiated and made by the driver. Only mechanical gear shifting mechanisms are allowed. This may include cables, rods, or other mechanical linkage systems. Any other assisted shifting mechanisms are specifically not allowed. This prohibition shall include electric solenoid shifters, air-shifters etc. Other similar devices are NOT permitted. Devices that allow pre-selected gear changes are also prohibited.

E. The clutch assembly is unrestricted except that the clutch engagement system shall be operated solely by driver input and may be mechanical or hydraulic in nature. The driver’s hands or feet must manually operate the clutch and there shall be no operation of the clutch by any assisted method. There shall be no modifications to the engine/transmission to enable the use of replacement clutch components or assemblies.

F. The use of jackshafts to transmit power from the output shaft to the rear axle is allowed.

G. Final drive chain tensioners are allowed.

From the F500 rules:
E.2. Weight and Dimensions
Minimum weight as qualified and raced, with driver, shall be 700 pounds (800 lbs. for AMW and Rotax 494 engines, 825 lbs. for Rotax 493, 850 lbs for 4 stroke 600cc motorcycle engines.
Wheelbase: Maximum 80”
Overall Length: Minimum 110”
Maximum 150”
Overall Width: Minimum 50”
Maximum 55”
_________________
Thanks ... Jay Novak
F500 since 1984

[Jim Murphy]

The first photos of the first F600 (in the rough) in the paddock of Road Atlanta are here -
http://www.eformulacarnews.com/viewtopic.php?t=2600

Enjoy.

Jim

[jdstuff]

Thanks for sharing Jim. Care to post up any specifics/problems you encountered during the build?

I don't know much about F500, other than seeing them run a handful of times. Is your rear ARB solution common, or something that you guys came up with?

[Jim Murphy]

Jason,
I will post a link to the first test day issues encountered and two very quick videos taken on the front straight of Road Atlanta shortly.
I am not familiar with the term "ARB", please define and I will answer.

Jim

[Jim Murphy]

Here is the link to the F600 test day issues thread and about 1/2 way thru them are the links to the short videos (be sure to enarge the screen and turn up the volume - the 1st one is better) -
http://www.eformulacarnews.com/viewtopic.php?t=2589

Jim