Author Topic: Horsepower required for a 10sec Dyna?  (Read 1303 times)

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Offline FXDBI

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Horsepower required for a 10sec Dyna?
« on: October 09, 2015, 11:38:58 AM »
Wondering what kind of horsepower would be needed to get a Dyna into the 10 sec bracket on the 1/4 mile.
I am sure there is a long list of " Other mods" required. This would be with a 150lb rider. Thoughts and input on the matter would be greatly appreciated. Figured this might be a good place to ask. Thks.  Bob

Offline strokerjlk

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Re: Horsepower required for a 10sec Dyna?
« Reply #1 on: October 09, 2015, 12:21:20 PM »

With a 620 lb bike and 150 lb rider about 115 hp will do it .
Like you said . Several other factors come into play .
But the calculator is very good at getting you close .

http://www.wallaceracing.com/et-hp-mph.php
A scientific theory summarizes a hypothesis
repeated testing establishes theory

Offline pwmorris

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Re: Horsepower required for a 10sec Dyna?
« Reply #2 on: October 09, 2015, 12:59:22 PM »
As said, a lot of factors at play here.
I weight 180 but my old FXR before all the mods was about 600 lbs.

Just a reference...

112 hp, ran 11.78 at 112 mph with a 1.7 60'
135 hp, ran 10.88 at 122 mph with a 1.6 60'

This was in my early days learning to ride at the track. No extended swingarm, no air or electric shifter, street style rear tire, no 2 step, 11 sec pass was with forward controls (sucked), basic clutch with no LU, heavier stock weight bike, and a stock, higher chassis platform and stance so it might be a good guide.

Now, get out there and get you some seat time!!!

Offline jam65

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Re: Horsepower required for a 10sec Dyna?
« Reply #3 on: October 09, 2015, 05:27:53 PM »
Mid 150hp with my Dyna and my best was 10.80 @123.80
1.65 60'
6.89 1/8th mile@ 102mph
 Trying out new gearing next weekend.

Offline Racepres

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Re: Horsepower required for a 10sec Dyna?
« Reply #4 on: October 09, 2015, 07:25:06 PM »
I typed a very long time...in order to delete it all and just say....Passes...and more Passes...worry about the ET at a Later date.
Seriously...I tell folks now...bring me at least 4 or 5 successive time slips at the same Number...and I'll know you are ready for "more"...

Offline jam65

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Re: Horsepower required for a 10sec Dyna?
« Reply #5 on: October 09, 2015, 07:50:17 PM »
My best pass came at the end of the day which tells me that their is room for improvement. I am far from being consistent but I still enjoy chasing that carrot in front of me.

Offline Racepres

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Re: Horsepower required for a 10sec Dyna?
« Reply #6 on: October 09, 2015, 08:03:35 PM »
My best pass came at the end of the day which tells me that their is room for improvement. I am far from being consistent but I still enjoy chasing that carrot in front of me.
So...If I had "tuned" yer bike midday...I would be yer hero...as it got better??

Again...IMO...Passes...
Or...Buy a Bike that the owner has been 10's...Now...you do it!

See!!!

Passes!!!!!

Offline jam65

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Re: Horsepower required for a 10sec Dyna?
« Reply #7 on: October 10, 2015, 04:11:58 AM »
My best pass came at the end of the day which tells me that their is room for improvement. I am far from being consistent but I still enjoy chasing that carrot in front of me.
So...If I had "tuned" yer bike midday...I would be yer hero...as it got better??

Again...IMO...Passes...
Or...Buy a Bike that the owner has been 10's...Now...you do it!


See!!!

Passes!!!!!
Some of us don't get many chances to get to the track. With that being said, I will take what I can get.
« Last Edit: October 10, 2015, 04:14:04 AM by jam65 »

Offline BB

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Re: Horsepower required for a 10sec Dyna?
« Reply #8 on: October 10, 2015, 05:22:01 AM »
I have a Mod bike with a 88" engine . It dyno'ed 140 hp . I have not had a chance to weigh the bike but the previous owner told me the bike weighed a little over 400 lb . He weighed 135 .He showed me time slip where the bike ran low 9's . The guy riding the bike for me now weighs 145 . The best we have ran is a 10.0 . We will get there some day.Right now our 60' sucks . I'm still learning the clutch.
« Last Edit: October 10, 2015, 05:28:50 AM by BB »
Ride Fast & Take Chances

Offline vafatboy1

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Re: Horsepower required for a 10sec Dyna?
« Reply #9 on: October 10, 2015, 05:25:46 AM »

I typed a very long time...in order to delete it all and just say....Passes...and more Passes...worry about the ET at a Later date.
Seriously...I tell folks now...bring me at least 4 or 5 successive time slips at the same Number...and I'll know you are ready for "more"...

Was fortunate enough to get an all day seminar and hands on trading from pro at MIR. Drilled into our heads were practice one thing at a time until you build the muscle memory.

Reaction time first, clutch and throttle next onto 60-foot time etc etc

Offline Racepres

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Re: Horsepower required for a 10sec Dyna?
« Reply #10 on: October 10, 2015, 05:36:22 AM »

I typed a very long time...in order to delete it all and just say....Passes...and more Passes...worry about the ET at a Later date.
Seriously...I tell folks now...bring me at least 4 or 5 successive time slips at the same Number...and I'll know you are ready for "more"...

Was fortunate enough to get an all day seminar and hands on trading from pro at MIR. Drilled into our heads were practice one thing at a time until you build the muscle memory.

Reaction time first, clutch and throttle next onto 60-foot time etc etc

Betcha he was a Metric Guy!
Try it...
Our folks are much more flexible than that!!

Offline westcomb

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Re: Horsepower required for a 10sec Dyna?
« Reply #11 on: October 10, 2015, 05:49:16 AM »
I would shoot for a solid 130HP and than like Marty said  .............. Pass's! ...... work on getting it down the track good! ...... and a tire that hooks! ...... :wink:

Horsepower to weight is a big part of it! ..... make more power than needed and its less work to run the number tho ....

Offline JamLazyAss

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Re: Horsepower required for a 10sec Dyna?
« Reply #12 on: October 13, 2015, 11:23:05 AM »
I don't hang around tracks often, therefore this question.

What is the significance of a 60ft time?
I've never heard the term before.
I'm not a proctologist, but I know an asshole when I see one...

Offline vafatboy1

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Re: Horsepower required for a 10sec Dyna?
« Reply #13 on: October 13, 2015, 11:50:36 AM »

I don't hang around tracks often, therefore this question.

What is the significance of a 60ft time?
I've never heard the term before.

The first 60 feet can be where significant time can be lost or made. 

Offline harleytuner

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Re: Horsepower required for a 10sec Dyna?
« Reply #14 on: October 13, 2015, 12:10:15 PM »
It's more than just HP, you have to put it to the pavement.  Too much power and you blow the tire off can be slower than less power that hooks up.  I saw a post on another forum, basically a post like this, then the OP posted a time slip, his R/T with .60
Enjoying the hell out of my "hotted" up twincam

Offline Racepres

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Re: Horsepower required for a 10sec Dyna?
« Reply #15 on: October 13, 2015, 12:15:59 PM »
It's more than just HP, you have to put it to the pavement.  Too much power and you blow the tire off can be slower than less power that hooks up.  I saw a post on another forum, basically a post like this, then the OP posted a time slip, his R/T with .60

But...R/T has Zero to do with ET...
I have some horrendous R/T slips...back when ya couldn't get a Single Pass [too many Participants] and I needed one.
Just let the other guy go...then make yer pass...I have qualified #1 more than once using that strategy!!!

Hell Red Lights mean Nothing during Qualifying!!!!
Time to Push yerself...Not during Eliminations!!!!


I'm gonna go back to Bring me a Timeslip....You get to 115 to 125 MPH you should get a 10...prolly high to mid depending on weight, and Equipment [60 ft]

The Track is your Dyno..Get into high gear and lets check yer HorsePower!!!!
« Last Edit: October 13, 2015, 12:21:52 PM by Racepres »

Offline vafatboy1

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Horsepower required for a 10sec Dyna?
« Reply #16 on: October 13, 2015, 12:22:32 PM »

I typed a very long time...in order to delete it all and just say....Passes...and more Passes...worry about the ET at a Later date.
Seriously...I tell folks now...bring me at least 4 or 5 successive time slips at the same Number...and I'll know you are ready for "more"...

Was fortunate enough to get an all day seminar and hands on trading from pro at MIR. Drilled into our heads were practice one thing at a time until you build the muscle memory.

Reaction time first, clutch and throttle next onto 60-foot time etc etc

Betcha he was a Metric Guy!
Try it...
Our folks are much more flexible than that!!

All I know is I took home the trophy the next day for my class.

Offline Racepres

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Re: Horsepower required for a 10sec Dyna?
« Reply #17 on: October 13, 2015, 12:28:10 PM »

I typed a very long time...in order to delete it all and just say....Passes...and more Passes...worry about the ET at a Later date.
Seriously...I tell folks now...bring me at least 4 or 5 successive time slips at the same Number...and I'll know you are ready for "more"...

Was fortunate enough to get an all day seminar and hands on trading from pro at MIR. Drilled into our heads were practice one thing at a time until you build the muscle memory.

Reaction time first, clutch and throttle next onto 60-foot time etc etc

Betcha he was a Metric Guy!
Try it...
Our folks are much more flexible than that!!

All I know is I took home the trophy the next day for my class.

Cool...Musta worked for Ya...See ya at the All Harley Drags!!!

Offline strokerjlk

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Re: Horsepower required for a 10sec Dyna?
« Reply #18 on: October 13, 2015, 12:36:33 PM »
I don't hang around tracks often, therefore this question.

What is the significance of a 60ft time?
I've never heard the term before.

It is a guide of how well you get off the line.
It shows how well your hooked up .
Once your dialed in and consistent .every 10th off the 60 ft ET equals 2-3  10 ths on the big end .
A scientific theory summarizes a hypothesis
repeated testing establishes theory

Offline FXDBI

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Re: Horsepower required for a 10sec Dyna?
« Reply #19 on: October 13, 2015, 05:21:40 PM »
It's more than just HP, you have to put it to the pavement.  Too much power and you blow the tire off can be slower than less power that hooks up.  I saw a post on another forum, basically a post like this, then the OP posted a time slip, his R/T with .60

 Yes I realize its more than HP  thing is if you don't have enough in the first place you will never get your target. Engine is coming out of the bike when the snow hits needed a idea how much a guy needs so to set a goal for the engine build. Turned 60 on Saturday and have made a goal to build and run a 10sec Harley. So open to all info I can get..  Bob
Added;  I am 5ft 11in and weigh in @150 and work physically every day so I am in not bad shape.
« Last Edit: October 13, 2015, 06:03:09 PM by FXDBI »

Offline Racepres

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Re: Horsepower required for a 10sec Dyna?
« Reply #20 on: October 13, 2015, 06:11:41 PM »
In a Light enough bike set up "all out" I been 10 Flat [bump the 9's time to time] with 100HP

My Guess is...in street trim...you may need all of that 100HP to get High 10 from a Streetable Bike.
Then...Tough pill to swallow, But, Someone with Experience is gonna do at least a 1/2 second..[if not more] better than a Casual experimenter.

Come to the Harley Drags, and look at the 11.50 Bikes...most will come close to an 11 flat...then look at 10.90 bikes...little more radical, and lots of 'em can do a 10 fifty. Nothing like Inspiration....

Offline FXDBI

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Re: Horsepower required for a 10sec Dyna?
« Reply #21 on: October 13, 2015, 06:51:56 PM »
In a Light enough bike set up "all out" I been 10 Flat [bump the 9's time to time] with 100HP

My Guess is...in street trim...you may need all of that 100HP to get High 10 from a Streetable Bike.
Then...Tough pill to swallow, But, Someone with Experience is gonna do at least a 1/2 second..[if not more] better than a Casual experimenter.

Come to the Harley Drags, and look at the 11.50 Bikes...most will come close to an 11 flat...then look at 10.90 bikes...little more radical, and lots of 'em can do a 10 fifty. Nothing like Inspiration....


http://www.castrolraceway.com/  That's the track here.   Bob

Offline Racepres

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Re: Horsepower required for a 10sec Dyna?
« Reply #22 on: October 13, 2015, 07:49:30 PM »
Don't know that track...But, i do know some Canucks that come to our Races...
Some will be in Rockingham in a couple of Days!!!

Offline strokerjlk

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Re: Horsepower required for a 10sec Dyna?
« Reply #23 on: October 13, 2015, 08:21:26 PM »
It's more than just HP, you have to put it to the pavement.  Too much power and you blow the tire off can be slower than less power that hooks up.  I saw a post on another forum, basically a post like this, then the OP posted a time slip, his R/T with .60

 Yes I realize its more than HP  thing is if you don't have enough in the first place you will never get your target. Engine is coming out of the bike when the snow hits needed a idea how much a guy needs so to set a goal for the engine build. Turned 60 on Saturday and have made a goal to build and run a 10sec Harley. So open to all info I can get..  Bob
Added;  I am 5ft 11in and weigh in @150 and work physically every day so I am in not bad shape.
over shoot the hp . you need 115 for your weight . try and make 125-130 hp. or more if you can.
BECAUSE
the little things add up.
60 ft is critical..the better you hook and launch the better your ET. So tire,clutch and gearing come into play.
if you foot shift with no kill ,use the clutch and back out of the throttle you are losing .40-.60 off the ET.
if you can foot shift quick without pulling the clutch lever you will get back .10-.20 of that ET. in other words a air shifter will pick up .40-.50 sec on ET.
Whatever transmission you have you need to gear so you can get in high gear and run it out the big end.
finding the groove is critical. if you go to the same track all the time ,you will pick that up quick.
all the little things can add up to the diff of 1-2 sec .
so if you have more power available.you can make up some of the little things on a street bike ,to help reach your goal.
added... a friend just put a ultima 131 in a 1999 dyna superglide 135/145 with the stock 5800 limiter he is running 10.80's
« Last Edit: October 13, 2015, 08:28:59 PM by strokerjlk »
A scientific theory summarizes a hypothesis
repeated testing establishes theory

Offline jam65

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Re: Horsepower required for a 10sec Dyna?
« Reply #24 on: October 14, 2015, 04:00:43 AM »
Jim, what kind of rear tire pressure  should I run or a least use as a starting point?