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[grc]

You can do dyno runs in any gear you choose, but obviously you can't run your motor up to 6200 rpms in 1st gear and hope it doesn't do some damage. So the common answer to that question would be YES, the dyno sheets you will be given would most likely be a 5th gear run. There's exceptions to every rule - - like what ? Well I doubt seriously a big motor bike would hit peak RPM's in 5th gear in an 8th mile drag race so that motor could well be tuned to peak in 3rd or 4th.

Yes, you are 100% spot on in my opinion. It is impossible to compare dyno sheets and come to ABSOLUTE conclusions which is why I get sort of wound up or amused depending on my mood at folks who live and die for their fricken dyno sheets. You can tell a lot about engine performance from a dyno and you can make adjustments to performance based on the information a dynomomter provides you. You can tune an engine to whatever your specific needs are and also test cams and other parts via the information provided but you don't know who's gonna win the race til the rubber hits the road. To say otherwise is foolish.

B B

    Well said Brian.

As for the choice of gear for the dyno runs, it seems the most common approach with the older 5 speed bikes was to do the runs in 4th gear, and now with the 6 speed bikes most places use 5th gear.  What you will probably find is that the choice of gear has more to do with safety than anything else.  If you run any relatively recent Harley up to redline in top gear, the rear tire will be traveling at more than 140 mph.  For an example, at 6200 rpm my 2005 SEEG would be running 150 mph in 5th gear.  The Cruise Drive bikes would be doing even more than that at 6200 in 6th gear. The tires aren't rated for those kinds of speeds, and your average dyno operator isn't probably very keen on having a tire come apart on him at those speeds (could make for a lot of excitement).


Jerry

[Half_Crazy]

You can do dyno runs in any gear you choose, but obviously you can't run your motor up to 6200 rpms in 1st gear and hope it doesn't do some damage.

If winding out 1st gear damages your motor, you didn't start with much.

So the common answer to that question would be YES, the dyno sheets you will be given would most likely be a 5th gear run.

Don't you want to dyno the bike in the gear that's nearest 1:1 ratio?

I doubt seriously a big motor bike would hit peak RPM's in 5th gear in an 8th mile drag race so that motor could well be tuned to peak in 3rd or 4th.

Are we talking about tuning or gearing? You lost me.

you don't know who's gonna win the race til the rubber hits the road. To say otherwise is foolish.

You can make a pretty damned good guess though.

[Half_Crazy]

Are all runs made in fifth gear?
Explain the CF:SAE lettering please.

There was a link provided in reply #3 by Old Lefty. You need to click on this link and read the information there. It will answer your questions.

http://www.bishopsperformance.com/dynoinfo.htm
^^^^^CLICK THE LINE ABOVE THIS TEXT^^^^^

Then, there is this really cool thing called "Google".
http://www.google.com/search?q=reading+dyno+charts&sourceid=ie7&rls=com.microsoft:en-us:IE-SearchBox&ie=&oe=&rlz=1I7ADFA_en
http://www.google.com/search?q=reading+dyno+graphs&sourceid=ie7&rls=com.microsoft:en-us:IE-SearchBox&ie=&oe=&rlz=1I7ADFA_en
http://www.google.com/search?q=understanding+dyno+results&sourceid=ie7&rls=com.microsoft:en-us:IE-SearchBox&ie=&oe=&rlz=1I7ADFA_en

[HILLSIDECYCLE.COM]

   Well said Brian.

As for the choice of gear for the dyno runs, it seems the most common approach with the older 5 speed bikes was to do the runs in 4th gear, and now with the 6 speed bikes most places use 5th gear.  What you will probably find is that the choice of gear has more to do with safety than anything else.  If you run any relatively recent Harley up to redline in top gear, the rear tire will be traveling at more than 140 mph.  For an example, at 6200 rpm my 2005 SEEG would be running 150 mph in 5th gear.  The Cruise Drive bikes would be doing even more than that at 6200 in 6th gear. The tires aren't rated for those kinds of speeds, and your average dyno operator isn't probably very keen on having a tire come apart on him at those speeds (could make for a lot of excitement).


Jerry

The gearbox is placed in the gear, that does not apply mechanical leverage either way.
1:1 ratio is the standard, which is about a 43-45 spark count.
Scott

[bigjohn]

You can tune an engine to whatever your specific needs are and also test cams and other parts via the information provided but you don't know who's gonna win the race til the rubber hits the road. To say otherwise is foolish.
B B

Guess I am foolish to think all the prepartion you do to ensure a win is done for chance. I was always taught you win before you race. As for guessing....I am usually right.
Why not dyno the gears ...that way you see your weak spots and strong spots.  I use a SERPT and have it piggy backed with a PC V. That way I have two different maps for each gear.
Gearing and tuning are two seperate issues.
I have the best of both worlds...I start with a strong engine.....then if I need too I have a 20 shot of nitros for those that seem to hang on...
Street racing and bracket racing are two different animals.
I knew this thread would go south................

[slacker2]

 Spiderman, you may not own a shop,however sounds like you really have a educated take on the subject !!!
I think that I found a decent engine builder/machinist/dyno guy in my state.
 I am expecting my new FLHXSE2 any day now.Thanks to you folks on this site I realized early to go outside of the Dealership for my engine build. Yeh I know it's a new big, one I always wanted and decided to Stage III right out of the box.
 To keep it brief, I met with the Engine builder and we are going to punch the jugs ten over, 10:5 pistons, polish the heads, change stock AC to a bigger K&N filter, TTS Master Tuner with a V&H 2-1 High Output pipe.
He has a good tuner rep. Has two dynos on site.

 SORRY: for going on, MY Question is to you and anybody that wants to put in,CAMS, what cam would work best in the 110 to produce those low end high numbers that you spoke of with my build ? it's either ask now or live with a bad decision for awhile. ~THANKS TO ALL THAT HAVE BEEN A GREAT HELP~

[Half_Crazy]

Guess I am foolish to think all the prepartion you do to ensure a win is done for chance. I was always taught you win before you race. As for guessing....I am usually right.

Amen. I'm sure if we looked at two bike's dyno charts... same dyno, same day... we could pretty much predict how things will go out on the road.

Researched enough to have read "War and Peace" before I spent a dime on performance. Wanted make sure that I got the results I was after. Have a pretty good idea what the results will be, not much guessing to it.

Some jackwagon on another Victory said to me once, "Nice bike, but mine's nicer".
I thought for a second..... Gee, if I had known there was a contest, I'd be winning it.


 

[Fired00d]

Spiderman, you may not own a shop,however sounds like you really have a educated take on the subject !!!
I think that I found a decent engine builder/machinist/dyno guy in my state.
 I am expecting my new FLHXSE2 any day now.Thanks to you folks on this site I realized early to go outside of the Dealership for my engine build. Yeh I know it's a new big, one I always wanted and decided to Stage III right out of the box.
 To keep it brief, I met with the Engine builder and we are going to punch the jugs ten over, 10:5 pistons, polish the heads, change stock AC to a bigger K&N filter, TTS Master Tuner with a V&H 2-1 High Output pipe.
He has a good tuner rep. Has two dynos on site.

 SORRY: for going on, MY Question is to you and anybody that wants to put in,CAMS, what cam would work best in the 110 to produce those low end high numbers that you spoke of with my build ? it's either ask now or live with a bad decision for awhile. ~THANKS TO ALL THAT HAVE BEEN A GREAT HELP~

You mention you have found a "decent" builder and if you are confident in his abilities he's the one you need to ask this question. He knows all the other components/modifications being done to the engine and should be able to match a cam up to produce what you are looking for. Many here will tell you if you don't know "how to" leave all the "components/modifications/build" to one person you trust.... starting to mismatch parts from different builds/suggestions/etc might not get you the desired results. Good luck w/your modifications and let us know how it works out.

 
Ride Safe,
Fired00d
 

[slacker2]

Oh, I'm going to go with what he comes up with. A smart man knows his limitations.
Thought a little homework never hurt anyone. Thanks.

[bigjohn]

Amen. I'm sure if we looked at two bike's dyno charts... same dyno, same day... we could pretty much predict how things will go out on the road.

 You have to watch gearing. Generally lower gearing will display lower numbers. Still the same output and power but does it a lot more quicker. Thats where the ET runs come into play.
 
Dynos are good tools ...they arent meant for who has the highest number or those dyno drags they have set up (they are usually a good 1 second slower in real track times).
As long as you use it for a tool and not bragging rights, they are very useful.

[Half_Crazy]

You have to watch gearing. Generally lower gearing will display lower numbers. Still the same output and power but does it a lot more quicker. Thats where the ET runs come into play.

Agreed.

I'm a life-long torque junkie. I will gladly give up peak horsepower for higher average torque across the tach. On the old set-up I had my choice between 2 exhaust systems. One made 125/125 and one made 120/130, I chose the latter. More "area under the curve". Horsepower wins drag races, but to me, torque rules the road.

[Spiderman]

Guess I am foolish to think all the prepartion you do to ensure a win is done for chance. I was always taught you win before you race. As for guessing....I am usually right.
Why not dyno the gears ...that way you see your weak spots and strong spots.  I use a SERPT and have it piggy backed with a PC V. That way I have two different maps for each gear.
Gearing and tuning are two seperate issues.
I have the best of both worlds...I start with a strong engine.....then if I need too I have a 20 shot of nitros for those that seem to hang on...
Street racing and bracket racing are two different animals.
I knew this thread would go south................

Why do people seem to see disrespect in words that are not intended as such. I stated in a couple of my posts that I knew there are site members with far more knowledge than myself. I was posting to the general membership as a whole which is basically folks who love to ride, like to twist the throttle a bit but are not racers, wrenches or expert tuners. I would say from your post that you are a bit of all three. Good for you. Folks like you help to flesh out a thread like this for those who really want to get into the weeds on a subject. Given what your post seems to imply, it would be nice to read what combination of parts you consider to be a solid dependable quick street engine. Also if you like, what you are using in your race bikes. I'm not sure what you mean in your last sentence. How has the thread gone south when we are discussing the variables which produce differing dyno numbers and what the charts themselves mean ? Lastly, I really don't care if Keith Ruxton built an engine, some people would be capable of putting what he'd built to use and some would not. And that's my point. The best dyno chart in the world doesn't mean you're going to win the race. You've gotta be able to ride the damn bike too.

B B

[bigjohn]

"You can tune an engine to whatever your specific needs are and also test cams and other parts via the information provided but you don't know who's gonna win the race til the rubber hits the road. To say otherwise is foolish."


Spyderman, when I stated about the thread going south, I guess I mis-understood what you were saying about being foolish. I thought that this was going to end up a pissing match. Thats the one thing that is bad about the computer age. You can only read the words and cannot decipher the meaning behind them. All in all this was a good post. I enjoying reading what other people have done and how their experiences worked out for them. I know a few times you guys have gave me good information and helped in fixing somethings. So with that in mind....please accept my sincere apology if I mistook your meaning. I guess we all should be thicker skined. I did agree with everything else that was being posted. There is always a lot of good information to be heard.
john

[strokerjlk]

Great thread going here.
my two cents.
timed dyno runs.
same everything.....same conditions,same bike ,same gear,same start/stop rpms,same throttle,same same same.
the only way to have a quicker time is ...more HP.

racing..tq vs hp
imagine shifting @ peak tq say 4000 rpms. then shifting @ peak hp say 5500 rpms.
now imagine if the peak hp @ 5500 rpms  flattens out and runs on out to 6500 rpms. so now you shift @ 6500 rpms and fall right back to 5500 rpms.

or forget it all and imagine a nitro harley shifting and making 500 hp @ 5000 rpms. better have bigger "ONES" than "A" Big dyno sheet.
of course this is always true in any race. big ONES win out.

[Steve Cole]

The biggest thing to remember is torque is what gets the load moving, so unless your going to drag race, the engine that produces more Torque in the RPM range that you ride it in is going to feel better than the one producing more high RPM HP! Think about it just for a minute without looking at a dynosheet at all. Where do you run the engine when you ride? Then take the dynosheet and tape over all the areas that are outside that range, then compare them. The one with the most torque in the range YOU run YOUR engine is going to feel the best and pull the hardest. I see way too many people getting sold on HP that doesn't happen until 4500 and up, while it's great for bragging rights at the bar and on the internet it doesn't do squat when your riding the bike for most people. Now if your plan is to build a race engine then higher RPM HP is what's going to win the race but I just do not see that happening for most riders on this site.