Forgive my ignorance... why do all of these conversions have the exhaust headers on the front side of the engine, where it is difficult to route? Why not turn the engine around so that the exhaust exits the back of the engine?
Because the rotation direction of the motor and gear box needed to propel the car forward works the best this way. Keeping the engine weight toward the center of the car is optimal.
It just seems like turning it around would bring some benefits. The sprocket would be much closer to the axis of rotation of the trailing links, the exhaust would be much easier to route, and the engine/gearbox could be tucked up closer behind the seat. However, I don't know how easy it would be to design a gearbox to reverse the direction of rotation, but I am certain it could be very small/light when done right.
Just turn the cylinder head around, not the block/trans.
However, that presents another problem, you would need to engineer a way to drive the cams.
Thinking. Thinking. Thinking. EDIT: I wonder if you could simply turn the exhaust ports into intake ports and vice-versa. That would be all about cam & ignition timing (reversing the 4 Stroke cycle),
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Last edited by Revs2-12k; August 19th, 2012 at 6:53 AM.
Reason: Thinking. Thinking. Thinking.
Seems like I remember that someone turned a F500 2 stroker around some years ago & it was ruled illegal. Jay probably knows more about it.
It was the gearbox required to change the rotation that was shot down. It was a simple two gear one to one box.
Before someone says it, you can't just reverse rotation on the 2stroke as you would have to change the position of the ignition pickup. You would then be breaking the "as delivered from the factory" rule.
Building headers just isn't that hard to go through all that hassle. I don't know what dimensions are used on these smaller motors but on one liter motors the entire engine bay would be filled with u-bends to get the right lengths. Its a neat idea but just not worth it IMO.
Seems like I remember that someone turned a F500 2 stroker around some years ago & it was ruled illegal. Jay probably knows more about it.
Scott, for your information, we were protested at the 2005 Runoffs for having the engine turned around in our car (RaKaVon). We were found legal at the Runoffs and Brian was leading by 4 seconds when he had a flat tire.
Over the winter the CRB "clarified" the rules on engine placement and we were then forced to redo the entire back of the car.
Brian won the Runoffs in 2007 with the car after we turned the engine around again.
My point is that we were ABSOLUTELY LEGAL when we built and raced the car the first year.
Scott, for your information, we were protested at the 2005 Runoffs for having the engine turned around in our car (RaKaVon). We were found legal at the Runoffs and Brian was leading by 4 seconds when he had a flat tire.
Over the winter the CRB "clarified" the rules on engine placement and we were then forced to redo the entire back of the car.
Brian won the Runoffs in 2007 with the car after we turned the engine around again.
My point is that we were ABSOLUTELY LEGAL when we built and raced the car the first year.
Thanks ... Jay Novak
Thanks Jay, I thought I remembered it was your car & a great idea. Didn't remember about the 05' Runoffs, shame about the flat. What was the reasoning given in the clarification?
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Thanks Jay, I thought I remembered it was your car & a great idea. Didn't remember about the 05' Runoffs, shame about the flat. What was the reasoning given in the clarification?
The CRB was convinced that if our reversed engine position was allowed, it would change the competitive picture of the class making all other cars uncompetitive. I am not sure that I agree but I totally understood the issue.
The change to the rule forced us to rethink some of our solutions and the car was actually better in the long run. I do think that another year of development with the original engine position (reversed) would have produced an even better car.
Brian won the Runoffs in 2007 at Topeka. He also won the Triple Crown and led every single lap of every race in 2007.
Just turn the cylinder head around, not the block/trans.
However, that presents another problem, you would need to engineer a way to drive the cams.
Thinking. Thinking. Thinking. EDIT: I wonder if you could simply turn the exhaust ports into intake ports and vice-versa. That would be all about cam & ignition timing (reversing the 4 Stroke cycle),
Well... Interestingly, we did this with the Ninja 600R engine when I was at Rolla on our FSAE team. Here are some pics. The 600R's used a center chain to drive the cams and it was drilling a single dowel, and oil hole and it worked great.. problem was the engines were behind flow in the CBRs which became the bullet of choice. This was the spawn of late nights and beers trying to figure out how to package a 58in^3 B&M supercharger we were given as sponsorship. Kyle Tucker, Alan Orban, Kieth Sigg, Tim Lewis, Dan Richie and I were the key conspirators. Everyone wondered if we had our own engine cast.
Chris Huskamp
Last edited by chris huskamp; January 1st, 2013 at 10:48 PM.
Reason: Left off a contributor..
As a great lesson in engineering built specifically around what to make and what to buy.. we chose to build our own fuel injection system as we were really limited to only Haltech at that time and we wanted more flexibility.. It worked great through all the dyno, road testing, and all the dynamic events.. until endurance. we lost a lot a parts in the box from fatigue of solder joints. DNF.
And that is why the FSAE programs are a valuable part of the training that young engineers get in school!
I also recall a school in either 1998 or 2000 that showed up with their engine turned around. That one ran a CVT off the clutch countershaft and the box was empty so the direction was correct. However, I don't recall the school name.
Weren't there some schools that toyed with the idea of spinning the engine backwards as well?
Pardon the necro-bump, have been lurking a bit and finally registered.
Quote:
Originally Posted by TestDriver
I also recall a school in either 1998 or 2000 that showed up with their engine turned around. That one ran a CVT off the clutch countershaft and the box was empty so the direction was correct. However, I don't recall the school name.
That sounds like Bradley University where I'm currently going. According to the guy who runs the program, around 2000 the team members didn't know how to shift and blew up engines so a student proposed using a CVT, which usually backfires because the engine teams don't know how to tune a CVT properly and usually end up blowing up the engines, there's a growing graveyard of Gixxer and CBRs sitting in the garage from over the years.
Why not turn the engine around?
you, Russ. 
