This article was written by Kyle Racing and is a good primer on dyno tuning. It goes along well with my thoughts on the subject discovered through trial and error, especilly the part about the final tune being no better than the tuner. Also explains why identical engines can test as much as 10 hp apart on the same dyno.

http://www.rc51.org/dynotuning.htm

Kruz

* Last updated by: Kruz on 5/18/2009 @ 2:18 PM *

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http://www.rc51.org/dynotuning.htm

^^^^easier access^^^^

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I would add that rather than tuning for the specific A/F ratio, you tune for best TTD. There ususlly will not be a big difference in A/F between the two, but it can sometimes mean 1/4 to 1/2 sec differences in TTD (quarter miles), just from a fews tenths of extra. or less, fuel.

* Last updated by: JDC on 5/18/2009 @ 3:23 PM *

Great Read

Good read, interesting info.

* Last updated by: farmer on 5/18/2009 @ 6:34 PM *

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Where is he getting these temp ranges when you look at a carb and that temp is rising too on that bike. So in proportion is the map just slightly adjusting for temp or is there map after map for temps and the carb could care less what temp is happening in bumfukegypt or in the mile high city of Denver, show me that temp range being adjusted with the carb jet.

As if to say the carb never ran well. As to say the carb draws what it needs in it's perfect environment is the vacuum suck out the jet hole is that proportion. Is the injector going to adjust for temp or vacuum pull? I mean, narrow it down. You know the temp is a cold engine start to normal running. How is it that jet was not changed for cold but here is the key is the "vacuum" not the temp is you have to build that theory up and now I see a flaw is ignore the, vacuum suck vs. temp.

So, is that temp change in rpms something in theory or fact? I bring vacuum. He brings temp. Who is rich or lean at a temp in the carb if the injector mimics the carb.

My question is if the vacuum runs the rich set or the temp overrides the vacuum since the jets are fixed. Get it?

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The Dynojet program is superb, but it is not perfect. The load control Dynojet 250 with the gas analyzer & interface that custom tunes the Powercommander units to any preset Air/Fuel ratio you choose at each individual rpm & throttle setting is a great tool for getting a base mapping done though it still cannot truly emulate real world loads on the motor & to get a truly optimal mapping you still need to fine tune your mapping by riding it on real roads. I prefer to use a Lamda sensor to get the A/F & tune from there, but still usually end up changing values beyond the scope of what the A/F ratio should be to cure drivability conditions, but again there is no better place than to start with a "professional dyno load base mapping well worth $200 or even $300 as long as the dyno operator knows what he is doing...

This is exactly what I have always said, a "custom" dyno tune is only the starting point for the final tune, we don't ride a dyno, we ride a motorcycle...... on the road and they are different. I've also noticed the temperature thing on my 14. If the temperature is 60 degrees or below throttle response seems to suffer, she just doesn't seem to pull as hard off the bottom. It's too bad we can't operate in a closed loop, the engine should pull harder when air temps are low and air density is high. The FI systems we have on our bikes are not as sophisticated as they would have you believe.

Kruz

* Last updated by: Kruz on 5/19/2009 @ 7:07 AM *

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Kruz

... If the temperature is 60 degrees or below throttle response seems to suffer, she just doesn't seem to pull as hard off the bottom

I agree with you. I use three maps, one for cold of winter, one for fall-n-spring, and another for summer. Seems to work out.

I agree with you. I use three maps, one for cold of winter, one for fall-n-spring, and another for summer. Seems to work out.

I need to try that, with my current mapping, spring and summer seem fine it's just when it get's cold it feels flat.

Kruz

* Last updated by: Kruz on 5/20/2009 @ 8:00 AM *

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Hey kruz are there any good or should I say is there a good shop in Dallas that u would recomend?

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http://www.southwestsuperbikes.com/

Give Southwest Superbikes in Dallas a try, I haven't had 'em do any dyno work yet but I've heard from others they're competent. Also Johnny Cheese Performance in Pfluggerville outside of Austin is supposed to be very good. I heard Johnny was going through a divorce a while back and was having financial problems though. I think I'd go with the Cheese first, he had the fastest Hayabusa in Texas for awhile and has a good reputation.

http://austin.citysearch.com/profile/map/36892449/pflugerville_tx/johnny_cheese_performance.html

Kruz

* Last updated by: Kruz on 5/20/2009 @ 12:30 PM *

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Thanks for the info cruz!!

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No problem bro, good luck with your dyno tune.

Kruz

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Thanks kruz but it will be awhile...I am in Iraq right now.

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TEXAS14, thank you for your service.

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not a problem toecutter

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Tex... You lucky dog. Wanna trade places? I'd have my own little war over there is bring you all home is never heard of the place. Thanks and hurry home...

Any spare Blu82's you don't need? Keep the 15k ears. Cup Pull of 23K's and bombs away! That should clear your path home.

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Lol..do u think u can take the 110 degree heat,and constant sand storms, and people trying to bring harm to u everyday..if so let me know..we are always hiring..lol

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Sounds like the Cali desert. No, I will bring the harm... Point the direction.

While those idiots try to work their world out, [doubt it] I came back from my friend's shop. They were putting a bike on the dyno, when I finally had to go. Anyway, I said to my guy, what A/Fratio he runs. Simple answer = Whatever makes the most HP.

So for you to chase 13 or 12:1 ratios, one day the HP will change. So back to basics is to find that peak HP for that run. Whatever that fuel trim turned out to be, that ratio made the HP. So, map wise, it is OK for a download, but to gain the best HP for the day, that dyno will pull that number out.

That means, the variables are the room temp; how fast/slow the bike is being cooled, the outside temp and the humidity all factor in. Obviously, there could be a better day with better numbers. It's still a crap shoot.

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