gears on 1/4 mile asphalt? what are u using?

[421alkybanshee]

im using a 17 front and 40 rear and can not get any better than 12 sec. at 105 mph

this is from a 16 front and 41 rear. I was at 13 sec and 104/103 mph

I didnt get much gain but I was running short 40 yard before the finish line where now I am not, it doesnt seem to be running out of gear like before but I figured I would get more than 1 or 2 mph with the sprocket change. Any help is greatly appreciated.

 

421 cub on alcolhol, 20x10x10 rear wheels with 107 hp

[SlowerThanYou]

im using a 17 front and 40 rear and can not get any better than 12 sec. at 105 mph

this is from a 16 front and 41 rear. I was at 13 sec and 104/103 mph

I didnt get much gain but I was running short 40 yard before the finish line where now I am not, it doesnt seem to be running out of gear like before but I figured I would get more than 1 or 2 mph with the sprocket change. Any help is greatly appreciated.

 

421 cub on alcolhol, 20x10x10 rear wheels with 107 hp

 

You are a little off, we run anywhere from a 2.05-2.17 ratio depending on different factors. Part of the problem is your tire size. You can run High 9s to low 10s on 20X8X10s. There are many other factors key to fast 1/4 mile times like: timing curves and dome configuration to name a few.

[SlowerThanYou]

Here's an old slip accomplished with 230 lb. rider, stock frame (335 lbs), 443cc cub on race gas and no power adder.

[421alkybanshee]

what about gears? I will double check on my tire size for sure. It seems to run really good the length of the track, not like i should be concerned about power,(timing curves,dome cuts)????

[SlowerThanYou]

what about gears? I will double check on my tire size for sure. It seems to run really good the length of the track, not like i should be concerned about power,(timing curves,dome cuts)????

 

I gave the ratio we have ran. Your 17/40 is a 2.35 ratio; you divide the larger sprocket by the smaller one. As for you not being concerned about power, our quad dyno'd 10 hp less than yours.

 

As for the timing curves and dome cuts, that's for you to figure out.

 

Now, for the gear gear ratios I told you we have run. It will take a lot of clutch tuning to make them ratios work.

 

I've given sound advice for the gear ratios and tire size. The rest is up to you to figure out how to make 10 more hp go faster

[J-Madd]

What ignition timing are you running?

[SlowerThanYou]

What ignition timing are you running?

 

Who are you asking?

[jsn210]

How well will the 2.05- 2.17 ratio work for 1/8 mile?

[SlowerThanYou]

How well will the 2.05- 2.17 ratio work for 1/8 mile?

 

We use the same ratio for both 1/4 & 1/8 mile. Things have to be done differently, but our best 1/8 mile times have come with the 1/4 mile gearing!

[J-Madd]

We use the same ratio for both 1/4 & 1/8 mile. Things have to be done differently, but our best 1/8 mile times have come with the 1/4 mile gearing!

 

 

I noticed that on your time slip, and thought that was odd. That's a good 1/8th mile time, yet its geared to run 120 mph. What gear are you in at the 8th mile mark?? I was asking the OP what timing, but if you want to give yours that would be great. I don't run asphalt, but would think that it would need to be a few degrees lower than what we run on dirt in 300 ft.

[SlowerThanYou]

I noticed that on your time slip, and thought that was odd. That's a good 1/8th mile time, yet its geared to run 120 mph. What gear are you in at the 8th mile mark?? I was asking the OP what timing, but if you want to give yours that would be great. I don't run asphalt, but would think that it would need to be a few degrees lower than what we run on dirt in 300 ft.

 

We have been faster than that in both 1/8 & 1/4, using the same gearing. On that run we were in 6th gear 100'-150' before the 1/8 mile.