Yes Sir, I got the shirts, Thank You Very Much!! But just to make you aware, I will have two bikes and I suppose one can be part of No Mercy Racing and the other can be.........[img]i/expressions/face-icon-small-shocked.gif[/img]guess what, [img]i/expressions/face-icon-small-tongue.gif[/img]

PS: Yes, theory is what we need, lets hear it DSNUT, [img]i/expressions/face-icon-small-wink.gif[/img]

 

LOL, OH you tell me AFTER i send you the shirts that your a switch hitter.. you play both sides of fence in shiat... [img]i/expressions/face-icon-small-smile.gif[/img] . . I hope some of the loyal Crew doesnt see you as a flight risk.

 

Nah, Im with ya til the end, [img]i/expressions/face-icon-small-wink.gif[/img]

 

Acceleration is an interesting thing. It can be done with low torque and high horsepower builds with lower gears to compensate for the torque deficit. An example of this would be a 73 hp (8750 rpm) stockbore at 14:1 with HP5's and dual carbs and a full race port head.

You could also go the big bore route where I have seen 76 hp but it is at about 7750 rpm with HP4s 13:1 and single lectron carb.

If you take these two motors and put them in equal chassis' you will have quite different setup. The 730 will make about 12 more hp at 4500 rpm as I recall. The torque numbers are higher at every rpm until maybe about 8500 rpm when the dual carbs on the stock bore help it rev out.

Thanks to the extra 2000 to 5000 rpm hp of the 730 and quicker acceleration in that range you can afford taller gears. These taller gears will exponentially pick up more speed for every rpm your engine increases. An example would be if you were to gain 5 mph for every 1000 rpm with a 16 tooth CS, lets say you would gain 7 mph for every 1000 rpm with a 17 tooth CS. Those are fictional numbers but I think you get the point.

Now you are using your torque curve to your advantage. It won't help you much on the flat track. I think I would rather have the stock bore with the listed mods for a 300' drag.

On the hill I would rather have the 730. The only instance in which the stock bore could win, that I can think of is if the hill steepness and length fell into the perfect equation of the stock bore being able to utilize its over rev at the top of the highest gear it could run and was able to carry more speed than the 730 could pull at a lower rpm in the next gear.

On these long hills the acceleration in the first 25% will have less to do with reaching the top first. The ability to gear so that you are in the sweet spot of your power to carry the most speed on the face of the hill will have more to do with winning. Torque helps greatly in this area. The more torque you have, the more torque you can afford to sacrifice by gearing tall and still be able to spin your motor up. Obviously the taller your drive gears are, the more speed you can carry in a given gear. I would rather pull 3rd with tall gears with the motor rapped out rather than trying to run lower gears and being forced to pull 4th or 5th on the same hill to have equal mph.....but that's just me.

We don't have close ratio gears in our DS's. The rpm's drop much further with each gear change than a YFZ450 does. That means the more weight becomes a factor, the broader we need to make our torque curves to stay in the meat of our powerband.

I will grant you that a 300 lb bike vs a 400 lb bike will be more of a desparity on the hill than it will be on the flat and in both cases it will effect getting out of the hole greatly. However, if I can bring enough torque to the table I won't need very many MPH advantage once we each reach our own respective terminal velocities on the face of the hill to make up a ton of ground in the last 75% of the hill. Your power to weight ratio will not save you if I have a MPH advantage and enough hill left once I establish that advantage. That being said, if I can't create that advantage with my extra torque, I will be screwed for the reasons you mentioned.[img]i/expressions/face-icon-small-wink.gif[/img]

The comment I made earlier about acceleration vs speed was in regard to this very point. I can be accelerating quicker than you while you are still pulling away because you are still traveling at a higher mph. Lets say you pull me out of the hole by 3 lengths (I think that is a realistic amount since my bike launches very hard). At the point at which you are 3 lengths ahead, I may be gaining speed much quicker than you once I get hooked up but I am still only going 20 mph while you are going 30. I am accelerating quicker but you will still be pulling away like crazy because 30 is 33% faster than 20............and that is a lot![img]i/expressions/face-icon-small-smile.gif[/img]

Hopefully this is a clear description of how I look at acceleration and speed. In any case, this is all speculation and i am comfortable waiting until Labor Day weekend to see what really works. I will have several gearing and tire combinations to find the best eta from bottom to top of the big hill. I think it will be more toward higher terminal velocity than it will be toward hook up...........I just can't sacrifice hook-up too much because I need to pull a high MPH number but I also need to get there as early on the hill as possible.

I'm going to bed! Good night.

 

And if I pull you by atleast 10 bikes with a 56-58hp motor in a 300lb chassis just how much horsepower and torque do you think its gonna take to overcome that disadvantage with your 400+lb bike?

 

Scott,

Based on your hill racing experience, how many of your idea's are based on theory and how many are based on what you have learned from experience?

My theories are based on the experience I have gained pulling the race hills in Oregon and racing on Thundermountain and Chokecherry at St. A's. All though I have never been to Sandmountain, Utah I think the information still has some relevance.[img]i/expressions/face-icon-small-wink.gif[/img]

I was happy to admit that you have the drop on me on flat drags. I know very little about what will make me successful in that arena.

Ron

 

I don't know. I have a feeling we will find out. Are you going to run your bolt on bike in its current chassis?


It will really be more of a product of curves and how much speed we can each carry once we are done accelerating. 10 lengths is only about 60 feet which leaves over a thousand feet of hill climb for me to reach your speed than start reeling you in. I would think if i can start gaining on you by the 200' mark, I would only need a few mph to pass you before the top............but that is just a theory. You are going to need setup on your side because you won't pull me by 10 lengths out of the hole on any chassis that has sufficient suspension to handle the whoops on Sandmountain. Your weight advantage might give you three lengths. If you had a ridged, you might get 10 lengths but I would be on my way back down the hill before you negotiated through the whoops[img]i/expressions/face-icon-small-wink.gif[/img][img]i/expressions/face-icon-small-smile.gif[/img]

 

In all honesty, I have no idea how my bike will perform on the hill. But thats why Im asking an expert in this field. I do know its gonna take a nasty bike to gate me out the hole though, [img]i/expressions/face-icon-small-wink.gif[/img] Oh and by the time we make it to DS Days, it will no longer be a bolt-on bike, [img]i/expressions/face-icon-small-shocked.gif[/img]....and yes, it will be in this chassis, [img]i/expressions/face-icon-small-wink.gif[/img]

 

I can argue some of your rev speed theorys... But I cant give my explanation because someone might use it. John force dont go tell his biggest opponent what works for him best on a certain track right. Ive been running big hills for a while and im sure you guys have too. When you go up in elevation like I have said before, watch out your in for a suprise. You can bench race and hill race. Dont get me wrong, I agree with a FEW things you said... But not all... For ONE thing when you gear taller you slow rev speed down right back down? Gear around your torq curve and hope your on a dyno that is a regular reader.jmo

 

I can accept this[img]i/expressions/face-icon-small-wink.gif[/img]...........accept for one thing. Who is your biggest opponent? Choose and i are both part of No Mercy racing........of course I will be representing Pat Both racing at DS days as an exhibition..........[img]i/expressions/face-icon-small-happy.gif[/img]