View Full Version : dyno tuning stationary, with ram air?

04-02-2010, 04:36 PM
something to think about
how does someone dyno tune a 1125r?
a dyno is stationary, how about the ram air effect?

04-02-2010, 06:45 PM
you asked a perfect question. I posted somewhere on here as well as another forum about this very thing.

unless you have the resistance wind calculations as progression and rider weight with mass area to add more progressive resistance you will never have a true reading on the dyno.

I can take a single map on the bike set the dyno one way it will read good in one place but bad in another. same dyno reset the values in the dyno and it will change the afr line and never touch the bikes settings.

set it to hard and to much and you get a rich mixture. set it to weak you get a lean mixture reading. All in all a properly set dyno to all aspects is very hard to nail. all a dyno does is get you close if set correctly. even then it still not 100%.

Dyno's can work against you terribly if you dont set them correctly. thats why every map I use to do was tuned to the rider on the bike. each bike will be different to different riders. Unless the riders are the same weight and size.

The other factor people seem to forget is a dyno is terrible when adjusting air temp,altitude, overall pressure and water in the air. these also effect a map. another test is a rainy cool day the bike 1 will make a map A when a hot dry day the map will be totally different.

what we have is sensors to skew the adjustments live as we ride. the mass air, air temp and O2. together these help adjust for altitude afr and density. take one out and you loos more than you gain in the long run. Unless you map it daily like the big race teams do on cars,bikes,trucks, ect. as weather changes they change the maps to suit for maximum power.EFI is different than carbs. efi does not relate to pressure sensitive sections on out side pressure where carbs do in the diaphragms and ect depending on brand. EFI is fixed and relies on feed back from sensors to adjust itself.

yet!... some guys think you can disable the sensors and have a one map fit all. you absolutely cant do that and stay correct at all times In the EFI systems. guess these guys know more than Bosch and ect on system adjustments and stabilization.

ram air does three things. cools,pressurizes, and turbulence in the intake. A dyno alone cannot help with these.

Real world, dynos can falsely read and many do due to undereducated readings and improper setup. If the operator cant tell how you set it up to be accurate with values. dont use them!!!

I set a progressive scale rated from rpm to weight divided by mass and resistance. advanced scales in dynojet. but even then every map every bike buell,harley,ducati,or suzuki has to pass the road logging stand alone. with out a road test logged you may and most of the time be off more than you think. adjust to the road(track) as a finale result. even though the dyno says perfect. it was perfect to the dyno not the real world usage.

Just beware of the dyno. It will lie, fool you and ect. Its a tool to get you close, not spot on or perfect unless you have one setup to only figure in the above mentioned data. Even then it not 100%.


04-02-2010, 07:04 PM
wow great writeup!

04-02-2010, 07:17 PM
I had a friend that use to own a dyno shop in GA mostly did american muscle alot of times to help with cooling and ram air they built a huge tube comming off a fan to help force air into the intakes they could control the fan speed and ramp the air up as the engine picked up speed

Mike Van V
04-05-2010, 03:15 AM
There's another thing the "dyno tuned" crowd doesn't seem to understand...there's a LOT more tuning to do thAn just "full throttle" tuning.
Cranking the throttle on full...completely bypasses all of the "steady state" (throttle) or cruise areas of the maps.

I've been tuning my CR by the seat of my pants, feel, milage and sound.
While this has taken me some time to get it so the engine's happy....the "hard on the throttle" areas of the maps....have been good for some time....!
The cruising down the freeway areas have been somewhat of a pain in the proverbial butt.

Beside....for my own part...I don't care if my CR does or doesn't make 140 wheel hp.....Just how long/often is anyone really at full throttle...?

I've now got my CR running as smooth as an I4, the power comes on great as I crank it to go around someone, or get out of the way of some numbnut behind the wheel.

Though Mike is correct about disconnecting the O2 sensors....if the AFV's are good at you normal altitude, and a 70-80 degree day. Things will still be better than the way the bikes came off the show room floor.

One more thing many don't mess with...the ignition timing.
If you don't...you're leaving power in your laptop...!


04-07-2010, 01:37 PM
I asked the question that started this because in the past I have paid for dyno tuning, what a mistake!
all they did was richen it up to the point that black soot covered the back of the bike, fuel mileage dropped from 36mpg to 26mpg. So I started doing my own tuning.
first bike with a seperate o2 sensor to a led display form jegs while riding. mpg was 36, dynoed down to 28 thenI tuned up to 44mpg
second bike hade o2 sensors and a recording while riding ability which as the ecm changes the VE it records the changes then averges out all changes in that box and tells you what to put in that box. 2mpg more no more flat spots
third bike haven't started yet.
I understand making the dyno load the bike harder thru math formulas to act as wind but dont unnderstand how to ram the air into the front of the bike to set VE levels.
so mike Im there with you on dialing it in by riding