Bike-engined Formula Atlantics in SCCA Club Racing

[RussMcB]

I haven't looked at a current GCR for this, but IIRC, there are no bike engines currently allowed in FA, right?

Any chance that might change?

Reason for asking: Sometimes I wonder if I might be able to afford more races if my Swift DB-4 had bike power rather than a Toyota/Staffs drive train. I don't know if that's really true, but it might be.

I realize, of course, that if the bike engine put out similar HP then it would be very expensive. I was thinking more along the lines of sacrificing some performance in exchange for less expensive running costs.

[Charles Warner]

Russ,

That idea was floated by the F/SRAC and got no support. You want to use a bike motor then FS or F1000 will be the place to play.

IMO that would be a bastardization of the class.

[Peter Olivola]

Well, in the spirit of the bleeding obvious, why not change your Toyota rebuild specs to something more durable.

[RussMcB]

Well, in the spirit of the bleeding obvious, why not change your Toyota rebuild specs to something more durable.

Well, if I understand what you're suggesting, buying new (less radical) camshafts and new lower compression pistons isn't exactly going to reduce my expenses, at least not for a long time. I imagine those items aren't cheap.

I know it's an idea with plenty of flaws, but if I did something like Sean O. did with his F1000 project, I could sell my healthy Toyota and Taylor breathed-on Staffs for a chunk of dough, maybe buy a Hayabusa or two and still cover the costs of building a new rear sub frame to bolt to the back of the tub. I'd have a car with less HP, but less weight and (hopefully) more miles between rebuilds.

I doubt I'll do it, but it is interesting to me so I thought I'd throw it out here to hear comments.

[RussMcB]

IMO that would be a bastardization of the class.

You mean, kinda like when they added FSCCA? :-)

[Charles Warner]

Russ,

That still is automotive power based as the class has always been. I feel you would be doing a disservice to your car to chop it up that way. Atlantics are not the cheapest things to run, but they can be run on a budget. If you want to do that get an FC with a tube frame and have at it.

[Dave Gomberg]

Sorry, withdrawn because of brain burp!

Dave

[RobLav]

I suggested that too - allowing m/c in FA. Got nowhere.

[RussMcB]

That still is automotive power based as the class has always been.

Yeah, my comment was kinda tongue in cheek.

I feel you would be doing a disservice to your car to chop it up that way. Atlantics are not the cheapest things to run, but they can be run on a budget. If you want to do that get an FC with a tube frame and have at it.

I've thought of that, but I like my car.

I do disagree with you somewhat about the "chop it up" part. It would be more of a un-bolt current stuff, fabricate new stuff and bolt it in. It could easily be reversed since there wouldn't be any "chopping" involved..

I do think my car has more value on the market if it is in original configuration. But if it is simply for my driving pleasure, there's no harm in thinking about changing things if they suit my situation better.

[Rick Kirchner]

Russ -

Sell the Toyo, buy a 2L BDP, take 500-1000 rpm off the top, and run FS. Or use a YAC that's been breathed on just a little. One of the guys out here runs a RT-4 with a YAC as a "F2" car.

[John Mosteller]

Put the bike engine in it and run FS or get a body from Loyning and run CSR.

[RussMcB]

<snip> ... or get a body from Loyning and run CSR.

Hmm. I'm not sure how a $10,000 body is going to save me money and give me a less temperamental drive train.

[Charles Warner]

Hmm. I'm not sure how a $10,000 body is going to save me money and give me a less temperamental drive train.

It won't, but it will mean you have less money to spend on the drive train.

[Stan Clayton]

Russ, shift at a lower RPM to dramatically extend the life of your drive train. Arne Loyning and I had this same conversation several years ago, and he opined that shifting at 9500 RPMs instead of 9800 would double the rebuild interval. Shift at 9200 (and gear the car for that RPM at top speed in top gear), and he thinks one can run a Toyota "forever". I offer up this option since you said that you'd accept some loss of competitiveness if it would cut your costs.

Stan

[RussMcB]

That sounds good to me. I've heard something along those lines before, and it makes sense. I talked with Bertils (builder of my engine), and he said newer camshaft designs have been developed since my last rebuild and they are much better at producing torque at lower RPMs.

Great. Now my dilema is solved. I can continue to look down my nose at silly bike engined cars (as I get passed by a screaming DSR! :-).

[formulasuper]

That sounds good to me. I've heard something along those lines before, and it makes sense. I talked with Bertils (builder of my engine), and he said newer camshaft designs have been developed since my last rebuild and they are much better at producing torque at lower RPMs.

Great. Now my dilema is solved. I can continue to look down my nose at silly bike engined cars (as I get passed by a screaming DSR! :-).

Yes, & I figure if I had $10,000 to put into my stock Busa powered Formula S RT5 you would be hearing another bike engine powered car screaming by!

[Tom Sprecher]

I know we're friends, Russ, but I have to agree with Mr. Warner in that you would be doing a great disservice to that car by chopping it up. In addition you are on the verge of heresy and may have to be reported.

I mean when you were talking about it in close company Saturday night I thought it might be the lack of beer, the pain or a combination of the two making you think that way but now I don't know. Jeez, man, guys have been known to disappear just for making comments like that. Now that you've gone public with it who knows when they'll come and get you.

BTW, while you're gone can I drive your car?

Thanks,

[Charles Warner]

Russ,

To back up Stan's comments - I ran the Cossie in the RT-4 and the 4AG in the Reynards. I shifted at 9200 even though Jennings and Arnie said I could go to 10000 (10500 with the 4AG.) Then Steve said that every second over about 9200 would take off several minutes of engine life. Plain and simple. Cosworth suggests shifting at 8800 in 1st and 2nd and 9000 - 9200 for the rest. As Stan says, gear it properly and give up the extra hp. I was able to get two years easy out of the motors.

I shift the DFV at 9800 even though the engine builder says I can go to 11000. The same engine builder says the engine cycle should be 15 hours. I have over 30 hours on my DFV and it still gives perfect leakdown and compression. You take care of it and it will take care of you. Get a rev limiter, set it at 9500, use shift lights set at 9200 and have fun.

Also, when time to rebuild there's only one word - Loyning. No one else should touch the Toyota. No one else but Steve Jennings should touch a Cossie.

[Stan Clayton]

Actually, you aren't giving up any hp by shifting at 9200, since that's peak hp (at least on my engine). Peak tq is 7600 IIRC. The secret is in the gearing. By shifting at 9800-10,200 you are past peak hp, but are gaining torque multiplication and going faster even though the engine is making less power.

I was interested in using a 4age in the 25 Hours of Thunderhill, and was talking with Arne about how to get it to last that long. Arne advised just what Charlie said...set the rev limiter at 9500, and shift at 9200. The engine still makes 245 peak, so I don't give up anything except ultimate acceleration.

Now that you mention cams, I do recall Arne saying something about them. He recommended the EFI cams for better torque, IIRC.

BTW, Arne also said that the piston pin bosses are the weak spot in these engines, and begin to fatigue above 9200 RPMs. So like Charlie says, every minute you spend above that you are cutting into the life of the motor. Keep it under that and your engine will last until a leakdown shows significant power loss.

Stan

[RussMcB]

<snip> ... you would be doing a great disservice to that car by chopping it up.

[SIZE=2]
Well, I'm glad that I at least got some very good, constructive comments out of this thread. Otherwise I'd almost have to say I was sorry I started it. I didn't think it was possible, but I may have lowered your opinions of me even lower than they were before! :-).

I didn't really want this thread to be, "What would you think of me if I did this?".

I still don't understand the "chop it up" comments. I'll need to invite you over and have you show me what part of the car would have to be "chopped". Were you thinking it was a tube frame car with bars that would need to be cut out of the way?

This pep talk about long lasting Toyota motors has certainly improved my outlook regarding racing my car over the next few seasons. Thanks, guys.
[/SIZE]

[Charles Warner]

[SIZE=2]
I still don't understand the "chop it up" comments. I'll need to invite you over and have you show me what part of the car would have to be "chopped". Were you thinking it was a tube frame car with bars that would need to be cut out of the way?

Russ,

Chopped might be symbolic of what you will do to the concept of the car. Like using a Mercedes to carry pig slop. Also, will there not be some bodywork changes? I realize you can put the thing back to original (although 99% of the time that never gets done as you wind up selling the engine/gearbox/subframe, etc.) but that isn't really the point. The car is an atlantic, it should stay that way. Also, weight changes and distributions would be different and I'd bet it would be an evil handling bugger. Sticking a MC engine in an atlantic chassis would be IMO a travesty.

[/SIZE]

[Jonathan Speed]

BTW, Arne also said that the piston pin bosses are the weak spot in these engines, and begin to fatigue above 9200 RPMs. So like Charlie says, every minute you spend above that you are cutting into the life of the motor. Keep it under that and your engine will last until a leakdown shows significant power loss.

As Stan states the above underlined, isn't the real reason that the pin bosses are weak due to the fact that the pins are tappered?

[superbikestore]

The problem you will run into after any conversion is done is you only have about 75 ft lb of torque (assuming 1000cc) and there is pretty much nothing you do to the motor that will increase this (except a turbo). The 200 HP tuned motors only make a tiny bit more torque.
1300cc may gain you another 10 ft lb.

FA and FC cars are really too heavy to run with this little torque so you will end up significantly slower than before. You really need a light car (600 - 700lbs wet) for the bike motor to be a big advantage, then they really do fly.
All the bikes are in the 400 - 500lb range at 1000 - 1300 cc.

David