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Wow! Looks like fun!
I wanna get me a dyno and have fun too!
How much does one of them go for?
I wanna get me a dyno and have fun too!
How much does one of them go for?
4gasem
Well-Known Member
The whole dyno? 30 or so grand...:confused2:
He paid 40 bucks for his run without A/F which he already knew.
Roy, get your ass to Topeka this weekend. lol The club is paying for it and you'll get multiple runs with a sniffer.
4gasem
Well-Known Member
I tried that Mark! I think his bike has a lot of potential... It just needs tweaked a bit... Oh and more than 400 miles (or whatever it is) on the fresh motor! :biglaugh:
QuarterHorse
Well-Known Member
Why are they dyno-ing that bike in 4th gear?
That's what Topeka does too. 5th sucks for pulling.
QuarterHorse
Well-Known Member
What's the 4th and 5th gear ratios? My bike's numbers were from 5th gear. I assume 5th isn't O/D and damn close to 1:1, which is what gives accurate dyno numbers.
Rusty McNeil
Well-Known Member
5th is very slightly overdrive.
I don't know about bike dynos but on cars they usually use whatever gear gives the closest to 1:1 from crank to driveshaft.
With all the primary reduction, and middle gear thrown in I don't know on bikes....
I don't know about bike dynos but on cars they usually use whatever gear gives the closest to 1:1 from crank to driveshaft.
With all the primary reduction, and middle gear thrown in I don't know on bikes....
4th is the only way they are going to be pulling any of my overdrive equipped engines. 5th will peg the dyno readings and drop the information. It's pretty wild to see the tire grow huge at 200mph+.
It's not enough to make any real difference from 4th or 5th gear on a normal trans bike.
Sean
It's not enough to make any real difference from 4th or 5th gear on a normal trans bike.
Sean
QuarterHorse
Well-Known Member
In all the cars I've had/seen when they do under driven dyno pulls it's higher numbers than the 1:1 gear, thus the reason I asked. I'm sure Sean knows though, and if the gears are close, I'm sure he's right on it not making a difference.
lankeeyankee
Well-Known Member
Every dyno pull I have made has always been 1 gear lower than your top.
6 speed tranny= dyno it in 5th
5 speed tranny= dyno it in 4th
4 speed harley= dont waste your time or take time away from the VMAX riders wanting to tune there bikes.:rofl_200:
6 speed tranny= dyno it in 5th
5 speed tranny= dyno it in 4th
4 speed harley= dont waste your time or take time away from the VMAX riders wanting to tune there bikes.:rofl_200:
QuarterHorse
Well-Known Member
Top gear USUALLY being O/D though. That's why I asked about the Max's gear ratios in the trans.
In a TH350/400/Powerglide or C4/C6 or TF 727/904 all being 3 speed autos, you don't do dyno pulls in 2nd gear, it's always the 1:1 gear ratio, in those cases top gear or 3rd (unless it's the powerglide then obviously high gear is 2nd).
I know bikes are a bit different from cars, but the ratio would be the same wouldn't it? Aren't we wanting 1:1?
You are correct that it's best to do a pull in the gear that is closest to 1:1
but think about this - you have changed the trans ratio but what are you going to do about the rear differential? If you change the rear diff from a 3.08 to a 4.56 do you think it will make a huge difference in the dyno readings?
but think about this - you have changed the trans ratio but what are you going to do about the rear differential? If you change the rear diff from a 3.08 to a 4.56 do you think it will make a huge difference in the dyno readings?
QuarterHorse
Well-Known Member
What change in gearing was made to see that much difference? Was it on the same day? If not it's not 100% valid. Last years dyno session was down 4-5 hp for everyone including bikes that had no changes from the previous year.
Sean
Sean
QuarterHorse
Well-Known Member
No it wasn't the same day, but similar air and the same dyno.
Went from a 3.90 to a 4.56 or a 5.13 I don't quite remember.
I know different day different power, but 7% is a jump when we're talking 500+rwhp.
That's siginficantly more of a change then simply dynoing from 4th to fifth gear.
Sean
Sean
