Transmission internals

[JohnPaul]

What are the rules on the internals of the transmission? I'm a little confused to whether the engine and transmission are considered as one and follow the same stock internals rules. In the FB rules they speak about them in separate sections. The reason I ask is because I was with an engine builder that swears that ceramic bearings in the tranny give him an 5+ extra MHP at the end of the straight at Daytona. He is a very respected guy that has been around for a long time and I'd have to take his word that he is correct with his calculations. When I read the rules, it looked like it doesn't say anything about not being able to change out any stock internals other than gears:

[FONT=Univers-Bold][FONT=Univers-Bold][FONT=Univers-Bold]H.8. Transmission/Final Drive[/FONT][/FONT][/FONT]

[FONT=Univers][FONT=Univers][FONT=Univers]B. The final drive ratio is unrestricted. Internal transmission gears shall [/FONT][/FONT][/FONT][FONT=Univers][FONT=Univers][FONT=Univers]remain stock[/FONT][/FONT][/FONT]

[FONT=Univers][FONT=Univers][FONT=Univers]I'm wondering if it would be legal and if people are already doing this?[/FONT][/FONT]

[/FONT]

[Northwind]

Since I don't have the rules in front of me, I can't really pick the rules apart. However I would only consider the areas that are clearly brought up as unrestricted like the oil system for example, if it is not clearly spelled out to be free or unrestricted, I would leave it at must remain stock. FB is considered a restricted class unless specifically noted. You do pose a good question though.

[F1000champ]

John Paul,

I can't speak for SCCA club racing, but in the F1K Series, all internals of the transmission must remain stock (OEM) and have been clarified in our rules.

Even though only gears are clarified in the FB club rules, I would assume (although that's a dangerous thing to do) that it would also pertain to all internal parts of the transmission.

[Wren]

[FONT=Univers][FONT=Univers][FONT=Univers]I'm wondering if it would be legal and if people are already doing this?[/FONT][/FONT]

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legal? Probably not based on the restricted nature of the class.

Is someone doing it? Probably, especially if he has already built motors for other FB cars.

If you are thinking about having this guy build a motor for you then I would suggest that you have a long talk with him about what he plans to do to the motor. I do not believe that these bike motor builders understand the FB rules. "Stock" bike classes allow much more latitude in what is done to the motor beyond what the FB rules allow.

[F1000champ]

I think the difficulty is that with the current FB club rules, there are many gray areas that can be interpreted by individuals in many different ways. What may be interpreted as legal in the current FB rules could very well be legal until there is a ruling stating otherwise. This is one reason why we are trying to bring more clarification as to what is and what is not legal in the F1K series rules. Believe me, it's a constant work in progress.

Understand, there are no perfect set of rules. There are loopholes that can be found in just about any set of rules, no matter at what level you participate. Just look at last year's McLaren F-duct and this year's blown exhaust gas diffuser system in F1. That's a perfect example, and at the highest level of our sport. You will find this in IndyCar, ALMS, and every series out there.

But, the basic rule of thumb is: If you're not sure if it's legal or not, get a written ruling by the Series Technical Director first. If you don't and if you try it, and if you get caught, and if the ruling by the Technical Director is that it is not legal, you run the risk of being penalized. As you can see, there are a lot of "ifs" here. Ask first, get it in writing and be legal. But get it from the organization's technical director, not another competitor, supplier, etc., and make sure the organizing body issues a Technical Bulletin clarifying any such ruling, so that all competitors are on the same page.

[RobLav]

It's my opinion that our intent in writing the rules was that all internals remain stock - as manufactured - including the transmission. All internals!!!

Ben, Sean, and Mike are probably on the same page.

[Brands]

Yup, all stock as far as I'm concerned.

[Rick Ross]

The reason I ask is because I was with an engine builder that swears that ceramic bearings in the tranny give him an 5+ extra MHP at the end of the straight at Daytona.[FONT=Univers][/FONT]

Was the extra 5 mph obtained with a motorcycle or with an FB car?

[JohnPaul]

Was the extra 5 mph obtained with a motorcycle or with an FB car?

good question, Motorcycles. I'm sure you would'nt get that much in a car application (i think).

[R. Pare]

The engine builder is blowing smoke about how much those bearings are worth.

Some quickie, top of my pointed head math (with no claims of accuracy - for demonstration purposes only!)

The HP it takes to push the car goes up as a cubed function of the speed, so that extra 5 mph - going from say 150 to 155 - could easily take 5 HP more, depending on what the drag numbers are (I'm not going to spend the time right now running aero numbers typical of open wheel cars - someone else can if they want more accuracy)

Transmissions in motorcycles are most likely generally in the 96-97% efficiency area (the best IRL transmissions are in the 97.5 - 97.8 % area, and I'm guessing that F1 transmission are maybe 98 - 98.5% at best with all of their special treatments, including ceramic bearings).

If your engine is putting out 180 HP, and the transmission efficiency is 97%, that means that you are losing about 5.4 HP through the transmission, with the majority of that being the moving of oil out from between the gear teeth and bearing rollers and balls - maybe 60-75% of the losses, leaving 25-40% in bearing and seal frictions, or 1.35 - 2.16 HP.

Typical single row ball bearing power consumption rotating in oil will be in the .05 HP or less area, depending on diameter, rpm, and load (roller bearings will consume more because of the width of the roller compared to the ball). A seal can consume .05 or so HP fairly easily. I did some dynoing of the ubiquitous Dasher dual row angular contact wheel bearing arrangement years ago. Fully assembled and properly preloaded it consumed about 3/8 hp at 1600 rpm - about 110 or so road speed in these cars. Without the seals (4 pieces) it consumed a bit over 1/8th hp, and with the grease replaced by oil (a film, not the typical flood that would be seen in a transmission, which would consume even more power) it dropped to a bit less than .075 HP.

Had that bearing been a full ceramic design, the final HP consumption would have been maybe another .01 - .015 hp less.

You can run more precise calculations using the equations found in bearing catalogues from companies like SKF.

Basically, there isn't enough power savings in the transmission to get you that 5-10 or so hp it would take to push the car 5 mph faster.

[iamuwere]

Richard, that is a far more thoughtful and intelligent reply than the response I was going to give, which was "That is BS."

[R. Pare]

None of that is to say that reducing friction everywhere you can isn't going to show gains on the track - it may only show as gaining 3 feet of ground on the car in front of you on a long straight, but that 3 feet can make a big difference over 20 laps.

But just a simple bearing change in the gearbox isn't going to give you another 5 mph on the top end!