Proposed rules for use of 600cc MC egines in the F500 class

[carnut169]

Have a single spec engine available for purchase or rebuild from pre-approved suppliers, who then seal the motor. LOTS of 06-08 600cc motors available- F600 would not even scratch the surface. It would be fair, inexpensive, and easy to police.

That's the way FE does it, right? I know it works for Rotax TAG karts.

This would be a logical step-up from kart racing with a slightly larger, more powerful, and safer car. The current pull-start CVT F500's just are not sexy.

[Marshall Mauney]

Have a single spec engine available for purchase or rebuild from pre-approved suppliers, who then seal the motor. LOTS of 06-08 600cc motors available- F600 would not even scratch the surface. It would be fair, inexpensive, and easy to police.

That's the way FE does it, right? I know it works for Rotax TAG karts.

Before you assume that this makes things absolutely equal, I'd suggest you go look at the dyno results for the sealed SRF engines at the 2007 Runoffs. The results are posted on the Enterprises website, and they're not pretty. I seem to recall differences of more than 10 HP, and these are supposed to be tuned for identical output. Keep in mind that this was the Runoffs, so assumably we're not talking about cars that weren't maintained or prepped. (You can probably throw out the bottom handful as being old, tired engines, poorly tuned, or having other driveline issues that impact the net power at the wheels.)

Having run RotaxMax for a year, I'd ask if you've seen the power differences between different carbs? Yes, the engines themselves are tuned pretty tightly and sealed, but the carbs aren't, and they aren't restricted....

FE seems to be pretty close so far, but I think that there's still enough difference in the prep and tuning (fuel pressure) to hide the engine-to-engine differences. As we get more cars, we'll know more. So far, I haven't had anyone pull away from me on a straight the way I've seen when I was down on power in other cars, but I don't have enough seat time in the FE yet to know for sure (I need to be closer to the front of the pack to really get a feel for the differences between car/driver).

My point is this: Yes, you can put together a sealed-engine program, but you have to have very tight controls on the actual power output and configuration, and you have to have someone to police the system. With multiple vendors able to seal an engine, I don't see how you can get things really equal - there's just too much variance between dynos. Then, you have to look at the items that are outside of the seals to see if there's anything there that can change the net output at the wheels (like the RotaxMax carbs). All of this costs money, so you've moved away from a "junkyard engine" program like the current Rotax 494/493.....

[teamfour]

Having talked with Dean Gaerte on this issue, he has been kicking around a sealed motor concept for the mini-sprints for years.

To take it one step farther and on the border of ridiculous, why not hand out ECUs at the start of a race weekend ala restrictor plates in NASCAR. If the motors are sealed and all the same year/make, this should cause no problems. It takes a couple of minutes to plug in an ECU. To go one step even farther, hand out a sealed motor each weekend since all of the mounts would be identical.

[Gaerte]

I feel that Jays plan is your best start given you do not yet know “how they will perform, how many will make the switch, you do not have years of experience with the 600 engines to be aware of what little tricks can be done, tech is only as good as your tech guy, you don’t want to create any battles out side of getting the engine approved, and many more reasons” (should have been a period in there some were lol).

I say try the proposed rules for a year. Stock engine; allow rebuilds to stock specification, any air box, stock ECU, any none “closed loop i.e.: Motty, MOTEK” fuel management “i.e.; PC, Bazzaz”, any oil-pan mods (to allow engines to set lower in the car), any wiring harness mods, and any exhaust (Jay as for the $1600 stepped headers, we will build any shape header you want for more than half of that muffler included).

As for the aftermarket clutch’s I would not allow them they cost too much money and the stock clutch is more than sufficient. Besides the fact that in testing we have found the stock GSXR600 clutch to be superior to all aftermarket products. The GSXR clutch is also adjustable in respect to deceleration slippage.

I would leave the chassis alone this year. Spend a year with just the engine, curving your weight rule as you go to keep them competitive with F500. You may find by next year you will have enough interest to make it a standalone class then the F500 guys have no worries. ??

No ones calculator is going to tell you the right answer you need to run a season to see what issues come up.

Best Regards, Dean Gaerte

[JonKerfoot]

Please understand, this is from a non-F500-participant viewpoint (oh, and if you're inclined to rail at someone not in the "fraternity" offering an opinion, don't bother), but I'm wondering if there are other alternatives to motorcycle motors for the class.

My impression is that the two-stroke snowmobile-derived engines, CVT and the lack of shifting were the differentiating features of F500. That sort of makes adding manually-shifted four-stroke motorcycle engines inimical to the character of the class, IMO.

Do any of the snowmobile manufacturers still sell sleds with 440cc motors? I know Polaris and Arctic Cat had nice liquid-cooled 440 twins up until a few years ago (I was looking on eBay for a motor for an A Mod or a Formuia Mini Indy car). Perhaps, if these motors are still in production, they might be a better fit with the "class philosophy" than 600cc motorcycle motors?

Just random thoughts on a Saturday.

[CDS]

Since the class currently has (I think) 2 allowable 2 stroke engines that the racers are allowed to tune to a certain extent, why not do the same thing when adding the 4S 600? Have 1 or maybe 2 allowable engines and allow limited tuning in the same vein as what is allowed with the 2 stroke. Seems like this is the philosophy of the draft rules proposal and to me it is consistent with the current class philosophy. The 2 strokes aren't sealed, so why think that you must seal the 4s?

I think that the amount of attention these threads are receiving from non-f500 people can only mean good things for growth of the class should the 600 be brought in.

[Jnovak]

Actually F500 has 6 legal 2 stroke engines. However the reality is that only 2 are used in national road racing and an additional 3 are also used in solo racing.

The legal engines are as follows:

Road racing dominant engines
Rotax model 494 non RAVE valve engine
Rotax model 493

Solo engines
Rotax 494 RAVE valve with limitations (this is recent & is not in the Road racing GCR
Rotax 494 Non RAVE valve engine
Kawasaki 440 engine
AMW 500 engine

Engines legal but not used
Fuji industries Chaparral 440 engine

Now it is obvious that NUMEROUS ENGINES have been added to the legal list over the years. I think it is now time for something that fits what is being produced in large quantities in todays market place & that is 600cc motorcycle engines.

As an example; There were 1.12 million motorcycles sold in the US in 2007. In 2007 there were 79,815 snowmobiles sold in the US. That is a ratio of over 14 to 1. I would bet that the ratio of 600cc motorcycles to 500cc snowmobiles is at least 50 to 1. Additionally snowmobiles are sold ONLY in northern states.


From the GCR:
"Engines shall be two-cylinder, two-cycle, water-cooled in stock configuration as listed below: Fuji "Chaparral" Model G44bw. "Kawasaki TC440A"/C-200, B-201, C-201, C-202, F-202, and G-203. The F-202 and the G-203 are electric start engines. Cylinder head P/N 440/2A is permitted for the engines listed. Only the "A" series engine is legal; the use of any parts from other Kawasaki series engines is prohibited. Rotax Model 494 and Model 493, single expansion chamber and electric and/or pull starter. Rotax 494 RAVE engine not allowed.

Thanks ...Jay Novak

[Tom Valet]

Jay, just as a point of curiosity for someone like me who is following this just because it's interesting but who has no dog in the fight other than that our car (FF) is usually grouped with F5, how much power does a Rotax make and is it comparable to the 600 engines? And how much if an advantage if any will the 6 speed transmission offer over the CVT? I realize all will be answered shortly when the new car is tested but what are your gut-feelings about how close the two cars will be to each other?

Thanks

Tom

[Gaerte]

Tom the peak hp is very close with the cycle engine having much more low and mid range torque. This will be a crap shoot. I would almost bet the CVT drive will be the advantage as it will keep the 500 at or closed to peak hp were the 600 will have to over come the drop in hp at each shift. Just a guess only time will tell.

Regards. Dean

[Jnovak]

Tom, the best 2 stroke engines make about 106 hp @ 8250 rpm and 69 ft-lbs of torque at 7850 rpm. This is what our winning engine made on the dyno.

The Susuki GSX-R600 engine makes about 109 hp at 13,500 rpm and 45 ft-lbs of torque at 11,750 rpm.

Now HP can be directly compared but torque cannot due to engine RPM differences. However if you correct for RPM then the Suzuki makes 67 ft-lbs of torque when corrected by gear reduction.

The efficiency of a CVT is all over the map from a low of about 75% to a high of about 88% depending on the vehicle speed, the ratio of the CVT etc. This is not nearly as good as the transmission in a bike engine, however if the clutchs are setup right an F500 will out accelerate a FFord up to about 115 mph because the CVT makes the engine run at peak HP all the time, while continually adjusting the ratio of the system. This is a very big advantage in that there is no loss due to shifting at all, particularly on the tight tracks.

My opinion is based on a lot of analysis & I think that our F500 chassis with a Suzuki GSX-R600 at an 835 lb as raced weight will be a bit slower than our Runoffs winning car was at 802 lbs (what we weighed at impound at the Runoffs in qualifying)

That's my best estimate for now. Testing will tell us for sure as we are doing the absolute best we can with the new 600cc car.

Thanks ... Jay Novak

[tedsimmons2]

Quoting: Jay

Tom, the best 2 stroke engines make about 106 hp @ 8250 rpm and 69 ft-lbs of torque at 7850 rpm. This is what our winning engine made on the dyno.
The Suzuki GSX-R600 engine makes about 109 hp at 13,500 rpm and 45 ft-lbs of torque at 11,750 rpm.
Now HP can be directly compared but torque cannot due to engine RPM differences. However if you correct for RPM then the Suzuki makes 67 ft-lbs of torque when corrected by gear reduction.

I’ve not had either a 500cc or a 600cc motor on a dyno so I have to rely on others for information. I’m assuming your 500cc made 106 hp and 67 ft-lbs of torque at the crankshaft? Was the 109 hp at the crankshaft or rear wheels for the Suzuki? The 2009 Kawasaki Ninja ZX-6R makes a claimed 124 hp crankshaft horsepower at 13,500 rpm, and 130 hp with full ram-air effect. It will make 105 hp at the rear wheel. (See my post above). With the 106 hp (crankshaft) verses 130 hp (crankshaft) and the quoted efficiencies of the CVT how is it you expect your F600 to be slower than a F500? I don’t intend this question to be confrontational but seriously looking for information. Thanks.

Ted Simmons

[Brands]

When I was racing back in the UK in Formula Honda we used the 600cc CBR motor. There was a year cap and the motors could be blue printed, but otherwise stock. The cars weighed in at 825lbs with driver. We had to drill lock wire holes at various points on the motor so if there was a protest the engine could be sealed in post race tech and inspected at a later date. I worked very well, the motors lasted at least a season without being touched and the cars where very quick. When the class lost Honda backing we switched to 1000cc motors (of any make) with the same rules. Again it worked very well with the year cap reviewed every other year. In my experience running these motors was cheaper than FF and much quicker. I don't see any reason why F500 should not have a year cap on motors.

[Jnovak]

Ted, I cannot attest to the new 2009 Kawasaki engine but I have talked to several engine builders who have done Suzuki 600 engines & that is what I have, I have spoken at length to George Dean who is a very highly respected engine builder for both DSR & F1000. His dyno is a modified chassis dyno that does not use a tire but is direct drive by chain to the bike transmission. The numbers he is getting are extremly close to the numbers I have been quoteing for the GSXR 600 engine.

Those are the numbers I have used for my analysis. I have created an acceleration analysis program for our F500 CVT cars. This analysis is spot on with our actual test data for the straightaway acceleration at several tracks including Mid-Ohio, Grattan & Topeka. Just to let you know, the "efficiency" of the CVT used in the analysis is from actual measured data in our car. I have modified the analysis to use standard transmission & chain drive efficiencies from racing transmissions using straight cut gears. This info is widely available to anyone who cares to look for it.

Now, what does the comparison of the analysis show? It shows that the 600cc engine (GSXR600) has slightly higher peak torque at the REAR WHEELS than the Rotax 494 engine has at the REAR WHEEL but ONLY NEAR PEAK HP. The 500cc Rotax with CVT has a HIGHER TORQUE to the rear wheels for a much longer time than the 600cc engine due to the fact that the CVT keeps the engine ALWAYS AT PEAK POWER RPM.

The net effect is that the CVT Rotax powered F500 @ 805 lbs weight is about .3 seconds faster down the straight at Mid-Ohio than the 600cc powered car at 835 lbs weight.

Now I could be full of BS but I do not think so. However when we test in a couple of months we will all know the reality. So hang in there & watch for the testing results with videos & data.

Thanks ... Jay Novak

[kmt63]

jay,

will you be testing the f600 with a f500 on the same day?or will you be overlaying data from other tests with the f500?would be nice to have a same day comparison of the two cars running.

kevin

[Jnovak]

Yes it is our plan to test with a couple of front running F500 cars. It all depends on who is available & the logistics of the whole thing.

Thanks ... Jay

[kmt63]

thats great jay.i hope some folks can make it to help with the testing.should be interesting.

thanks
kevin