Ram Air and the dyno

[BusaSnoop]

How is ram air compensated for when dyno tuning. I had my bike dynoed took fuel and timing away made good power went to the track and it ran terrable. End result put fuel and timing back at it gained 2 tenths back in an hour of testing. Has anyone ran in to this and is their a standard amount that needs to be added back after dynoing.

[KSpecII]

ram air is not compensated on the dyno if the tuner follows the std a/f... so i guess you may be running lean when the ram air effect kicks in...

[entropy]

Does the Busa have an air pressure sensor monitoring the airbox/TB's?????

If so, wouldn't the ECU compensate for any ram air increases???

[KSpecII]

there's an IAP sensor.. but the ram air effect is normally not in full force due to the poor sealing of the air box to the ram air tubes...

the issue would then be when the ecu compensates for the air pressure, will it be sufficient given the different "breathing" patterns of the modded bike..

[Pete]

Does the Busa have an air pressure sensor monitoring the airbox/TB's?????

If so, wouldn't the ECU compensate for any ram air increases???

Yes but it only compensates for vacuum, not positive-pressure.

[whtrthanu]

when I tune on my dyno, and im sure that other shops that are experienced do, you do not have the best or peak hp numbers after you tune for track simulation....
i used a data logger on a test bike and went from the dyno to the track, and you be suprised how off the tune up is at high speed from the dyno...

[glenn71]

I,ve read each gear has differnt enrichments to allow for ram air..2 for 3rd,.3 for 4th,.4 for 5th,.5 for 6th.As my busa seems to make the most power (ON THE DYNO) around 13.6-7 and the bike is tuned in 4th gear on a dj250i my tuner maps it to 13.2 in that gear.Now if suzuki equated .3 for that gear enrichment the assumption is it,ll end up around 13.5 on the road.Interestingly those that have the gps mod and yosh tune their bikes may discover the .4 enrichment now applies to all gears making 1st and 2nd a bit rich and one guy i know struggled to lean it out on idle because of this.

[entropy]

Does the Busa have an air pressure sensor monitoring the airbox/TB's?????

If so, wouldn't the ECU compensate for any ram air increases???

Yes but it only compensates for vacuum, not positive-pressure.

please explain, i don't understand.

Also, where in the intake track is the Busa sensor? 

In the ZX12 the MAP sensor takes its feed from the TB, and the pressure is always less than ambient on the dyno.

However, at 190mph the ram air gets it up to ambient, just.

[enginetuna]

I generally find that on my superbike customers we will find on average it runs about 0.2 AF leaner on track than how i setup on dyno.  So 13.2 becomes 13.4 on track.  Fan air speed on my dyno is around 60-70mph.  But then these guys rarely go over about 150mph and that is only for a very short time.
One thing you will also find on some of the suzuki ecu's is the fuelling changes depending on how fast the engine accelerates.  I was testing a k6 1000 last week and found that 4th and 5th gear roll-on fuelled differently, as did sweep testing for the same gear and then step testing again was very different.  They do weird things with the timing and upper butterflies depending on load and rpm rate.  And upper/lower injector duty also changed.

[Pete]

Does the Busa have an air pressure sensor monitoring the airbox/TB's?????

If so, wouldn't the ECU compensate for any ram air increases???

Yes but it only compensates for vacuum, not positive-pressure.

please explain, i don't understand.

Also, where in the intake track is the Busa sensor? 

In the ZX12 the MAP sensor takes its feed from the TB, and the pressure is always less than ambient on the dyno.

However, at 190mph the ram air gets it up to ambient, just.

The anual says the sensor only compensates for vacuum, it's branched off all 4 tb's.

[gazza414]

Read also PetriK's thread 

also without a wideband its in open loop and the percentages are SFA

you can do the calcs or data log the airbox pressure..ya gotta be going fast for any "BOOST" influence

[PetriK]

Yep - as far as I have tested the IAP sensor does not adjust for anything at WOT (wide open throttle, well turns the fuel off if enginge stalls etc. but under normal running conditions).

There is an acceleration enrichment there, but that is related to the TPS change e.g. when doing a normal cluched gear change or trying to shoot for the best 60ft time. I am particularly intrested to tweak the accel enrichment (together with ignition) for first 60ft...

The key point is that there may be 3% difference between gear 1 low load and gear6 full load settings. With guys running TRE you can only have either rich streetbike or lean speedbike. This is one of the reasons why I am so keen on tuning the ECU directly to remove the 6th gear rpm limiters. If you dyno in static air (blowers do not really generate any ram air effect) you should dyno for a tad bit rich. Who cares if the mapping is done to +-1% if in real word its gonna be off for 3% at LSR events.

Below you can see the ram air compensation maps for 1st gear, 6th gear low load and 6th gear full load situations. Below that you can see the changes in terms of injector pulsewidth between gear 1 and gear 6 at 10.000rpm @ full throttle. This something to bear in mind when comparing air pressure when running 200mph vs. fans at dyno. It comes to around 3% which ever way you calculate it.






Anyhow its possible that Suzuki is fooling us and running the engines a bit rich at those speeds just to protect the engine so we dont know if those numbers are truly real. Only the guys who have been running WBO at LSR can give an exact answer to that. I would not trust the intake pressure sensor for that information as that affects not only the pressure but also propably the pulse tuning of intake and through that to the VE of the engine for any given speed. So only WBO can give an exact answer.

[entropy]

Petrik,
GREAT investigation!

If i understand you the Intake Air Pressure has no impact when in 6th gear.

Is the Intake air Pressure the same as the Manifold Air Pressure mentioned above?

 Does the Busa also have an atmospheric air pressure sensor.

On the ZX12, I was under the impression that the ECU took the differential between the MAP sensor (TB's), and the atmospheric pressure sensor (in the tail) and somehow computed changes to fuel.  Is this not true?

I am a bit confused
(not an unusual state)

[PetriK]

You are absolutely correct about ecu using the diffence between IAP (intake air pressure, ie. manifold pressure) and ambient pressure.

Anyhow for fuel calculations the IAP is not taken into account after appr 10% throttle opening (appr 28% voltage). Instead the ambient pressure affects also the TPS maps so by modifying the ambient sensor (with an additional resistor) you can fool your ecu to run higher rpms before getting FI light (in theory) and only after remapping all the fuelmaps (or getting the DaveO extended ecu mod).

[gazza414]

The fuel maps will need to be remapped as you prob know Karl as Dave O's and others  mod is simply to change the clock speed.

[BusaSnoop]

So to put all this in to terms most peaple can understand. If your tuning for peak H.P. on the dyno you will need to add 2-4% full throttle fuel at the strip\street to get the tune up right.  Thanks for the info to all.

[entropy]

The fuel maps will need to be remapped as you prob know Karl as Dave O's and others  mod is simply to change the clock speed.

gazza,
yep, i have a DaveO modded ECU, it works great, and as you poing out it needed just a titsch more fuel to accommodate the increased clock speed.

Also, i send it back back to DaveO each Spring and Fall to have the clock adjusted for Daylight Saving Time...

[gazza414]

The fuel maps will need to be remapped as you prob know Karl as Dave O's and others  mod is simply to change the clock speed.

gazza,
yep, i have a DaveO modded ECU, it works great, and as you poing out it needed just a titsch more fuel to accommodate the increased clock speed.

Also, i send it back back to DaveO each Spring and Fall to have the clock adjusted for Daylight Saving Time...

and here I'm thinking you guys dont have a sense of humour!!!!

Dave struggled with my clock speed ...14 hrs ahead here mate...my ECU runs in a cryo bath

all the best anyway Karl with that Kawa and hope ya break some records..head down , ass up seems to work at speed

[enginetuna]

So to put all this in to terms most peaple can understand. If your tuning for peak H.P. on the dyno you will need to add 2-4% full throttle fuel at the strip\street to get the tune up right.  Thanks for the info to all.

I would say at most 2% unless you are running way past 160mph

[Rollin99]

when I tune on my dyno, and im sure that other shops that are experienced do, you do not have the best or peak hp numbers after you tune for track simulation....
i used a data logger on a test bike and went from the dyno to the track, and you be suprised how off the tune up is at high speed from the dyno...

a good tuner will do this everytime if a customer is a track guy...you gotta know usage of the bike to give the customer the best tune...

[glenn71]

when you say 2% more fuel how does that equate to air fuel.is that like .2-.3 air fuel.I doubt it  as i saw that much change with directed fans on a dyno.I would have thought up to 1.0 change at approx 150mph?A wideband can log a map signal and i wish to do this at the drags this year with differnt air box ideas.people say theres barely any boost until 150mph.Have they compared airbox negative pressure on a dyno to pressure at speed.Less negative pressure is still better albeit not yet positive.

[PetriK]

That 2-3% number came directly from comparing injector pulsewidth with top speed on 6th gear (over 300km/h) and cruising speed from ECU factory settings. The point here is that usually when dynoed with TRE you only use one gearmap and compensate for static ramairpressure which does not reflect the real world conditions. The ramair pressure changes by speed that is within ecu calculated based on RPM. The powercommander map is based on RPM. So when dynoed and tuned against static airpressure you actually kind of reprogram you bike to remove the ramair compensation. The net result you can see from the powercommander maps - often with mildly modified bikes at dyno you take fuel off from high rpm to have optimum power under static ramair pressure...

For dyno you really should program the ecu for a flat 5th gear RAM air compensation map which equals the airpressure from cooling fans in to the ECU and then dyno the bike. Then after dyno you should reprogram the 5th gear compensation map back to original. With this method your fuelmap is not compensated against the 5th gear ram air compensation map and in real world driving conditions your afr ratios will be closer to the optimum. (This assuming that you dyno on the 5th gear). Alternatively of course a datalogger and real world situations will be the way to do it, especially as you one finetune the gearspecific ram air compensation maps by programming the ecu for optimum afr. Which ever way, having the TRE connected will mess the afr when speed increases. Well - in truth we are talking here only a couple of ponies, TRE is messing up the way how Suzuki designed fuel maps: to be as perfect as possible.

There is no need anymore to have TRE on the bike that in practise removes the ram air compensation. The top 6th gear speed limiter can be removed by reprogramming the ecu which allows the ram air compensation to work correctly. .... well the above really applies only to NA engines ... with nitrous and turbos the fuel requirement is dependent on other things. But also with turbo and nitrous reprogramming the ecu to remove the top speed limiter and raising the rpm limiters has its benefits. For nitrous I really like the ecu feature to reprogram the intake flap solenoid control to act as a nitrous window control switch.

But this is of course personal view from only... and I am not a bike tuner with LSR records.

ps. The dyno fan  may not be directed directly to the nose causing maximum pressure in the intake, usually they are directed towards the radiator for maximum cooling.

[enginetuna]

when you say 2% more fuel how does that equate to air fuel.is that like .2-.3 air fuel.I doubt it  as i saw that much change with directed fans on a dyno.I would have thought up to 1.0 change at approx 150mph?A wideband can log a map signal and i wish to do this at the drags this year with differnt air box ideas.people say theres barely any boost until 150mph.Have they compared airbox negative pressure on a dyno to pressure at speed.Less negative pressure is still better albeit not yet positive.

Here is dyno AFR (lower graph) and Motec lambda logging (upper graph) from the following day.  The logging is in 6th gear on a gsxr and the dyno run in 5th.  Looking at the 2 graphs, dyno lambda is 12.68 and track lambda for same rpm at 145mph is 12.797
My dyno fan is pushing around a 65mph air at the front of the bike so the ramair system is seeing a bit of this.

[glenn71]

great stuff.

[PetriK]

Here is dyno AFR (lower graph) and Motec lambda logging (upper graph) from the following day.  The logging is in 6th gear on a gsxr and the dyno run in 5th.  Looking at the 2 graphs, dyno lambda is 12.68 and track lambda for same rpm at 145mph is 12.797

Excellent - do you have the intake air temperature, ambient pressure and TPS sensor readings for these two different measurements ? Fuel injector pulse is highly dependent on ambient pressure as it is calculating the pulsewidth by based on difference between ambient and intake air pressure.

[enginetuna]

I will have to look into this over the weekend.  The motec will have logging for everything in it providing i told it to log.  Will have a look when i have time and get back to you

[gazza414]

Here is dyno AFR (lower graph) and Motec lambda logging (upper graph) from the following day.  The logging is in 6th gear on a gsxr and the dyno run in 5th.  Looking at the 2 graphs, dyno lambda is 12.68 and track lambda for same rpm at 145mph is 12.797
My dyno fan is pushing around a 65mph air at the front of the bike so the ramair system is seeing a bit of this.

ET, I hope your not suggesting the 2 A/F values are due to ram air?

[enginetuna]

ET, I hope your not suggesting the 2 A/F values are due to ram air?

I'm not sure what you are asking me here?
One chart is from the dyno the other from track.

[gazza414]

ET, I thought you were suggesting that at the track and at  the dyno you could compare A/F's ? even down to 3 decimal places ?

[enginetuna]

Excellent - do you have the intake air temperature, ambient pressure and TPS sensor readings for these two different measurements ? Fuel injector pulse is highly dependent on ambient pressure as it is calculating the pulsewidth by based on difference between ambient and intake air pressure.

I have just checked the map along with the tempertures and pressures.  They were close enough to not be corrected loads.  Both runs were at 100% throttle.  MAP was within 2kPa but that could be from the change of location.  Further detail from track below, hope its of use.

[enginetuna]

ET, I thought you were suggesting that at the track and at  the dyno you could compare A/F's ? even down to 3 decimal places ?

Not at all.  There is a discussion between the difference between dyno and track AFR.  I'm merely showing what i had on dyno one day then track the next.  Maybe my correction tables are more accurate that suzuki?  I doubt it.  Don't know.  All i'm showing here is logging at pretty close to 13k rpm from both places.  But the bike was mapped on the dyno at a set AFR with a 65mph (approx) wind then the next day its on track doing 145mph and the AFR is pretty close, like less than 0.2 difference.  Now if there was a huge amount of extra air being rammed in there it would be showing lean but its not.  I see far more of an AFR difference between a hot and cold day on the dyno.

[GenII Busa]

How is ram air compensated for when dyno tuning. I had my bike dynoed took fuel and timing away made good power went to the track and it ran terrable. End result put fuel and timing back at it gained 2 tenths back in an hour of testing. Has anyone ran in to this and is their a standard amount that needs to be added back after dynoing.

When tuning on the dyno, make the A/F 0.3 ~ 0.5 points richer to compensate for the ram-air effect on the road.

There have been numerous discussions if the Busa actively compensates for ram-air ... the resulting answer is no.  It's most likely compensated buy the ECU knowing what gear it's in, and what the engine RPMs are ... thus, giving it a calculated bike velocity and an A/F compensation based on the bike's speed since the ram-air pressure vs. speed curve is known by Suzuki.

This also brings up another interesting issue.  If a Busa is running a TRE that simulates something besides 6th gear then the ram-air compensation is thrown off slightly because the ECU thinks the bike is going slower than it really is.

[BusaSnoop]

If this will help enyone from my peak h.p. on dyno to peak performance at the strip I had to do a lot of tuning. I ended up with 4% more fuel and advanced the timing 4 degrees. I did it in small amounts and checked my ET splits I got 2.5 tenths back that I lost after dyno

[BusaSnoop]

One more thing I forgot. The TRE I had made my bike 1 tenth slower

[PetriK]

Not at all.  There is a discussion between the difference between dyno and track AFR.  I'm merely showing what i had on dyno one day then track the next.  Maybe my correction tables are more accurate that suzuki?  I doubt it.  Don't know.  All i'm showing here is logging at pretty close to 13k rpm from both places.  But the bike was mapped on the dyno at a set AFR with a 65mph (approx) wind then the next day its on track doing 145mph and the AFR is pretty close, like less than 0.2 difference.  Now if there was a huge amount of extra air being rammed in there it would be showing lean but its not.  I see far more of an AFR difference between a hot and cold day on the dyno.

Thanks - a quick look to the pictures makes me to notice the following:
- There is 4C degree difference in intake temp
- There is 2.6kpa difference between manifold pressure (could be because of ambient pressure difference ?)
- No information about ambient pressure which is the single biggest contributing factor to AFR
- About 5 degree difference in engine temp, in busa that would not make difference in AFR - dont know about Motec
- According to the rpm behaviour it looks like the bike has been accelerating rapidly introducing accel enrichment factor in Busa, dont know how Motec owrks
- No information if Motec uses manifold pressure at the given engine conditions to adjust AFR, busa certainly does not for constant full throttle positions.
- No information about gear compensation maps of the given ecu
- Unknown battery voltage which also affects compensation
- Slow speed to see the ram air effect compared to busa top speeds. The air pressure is not linear to speed, its rather exponential.

Would not use that information provided in those pictures much for making decisions to tune my Busa for ram air. If you can find the ambient air pressure for both then could estimate the differences.

I am not trying to argue here - all written earlier in this thread is just facts based on what anyone can learn by reading the ECU and learn from that how Suzuki has designed the engine to work.

One thing though - 65mph airspeed from dyno fans, that is about 104km/h. Normally when driving that speed I usually prefer to have my visor closed as the wind resistance is high when sitting up on the bike. If that airspeed is hitting the ram air tubes and driver behind, I would need to wear goggles when dynoing the bike...

[enginetuna]

Petrik, i'm not sure you are reading the graphs properly.  The first i posted is an 8-second window of a 10-minute qualifying session.  The second is a 20-second window of an 11-minute race.  The dyno chart i posted under the first motec log is an rpm trace similar to the on track trace above just to show what AFR was in both situations.
I do not understand where you are getting a 2.6kPa manifold pressure difference from?  If you look at the 2nd picture i posted the cyan coloured line which is manifold pressure and during the 20 second window of logging i am showing the manifold pressure varies from 34.7 to 101.9kPa.  The figures you see on the right of the screen are just the figures at the point of time where the vertical blue line on the graphs is at this specific point.  The manifold pressure jumps around a lot even under constant tps conditions.
Ambient pressure is not logged here, i've just checked the logging setup.
Depending on the bike, i do have to wear goggles.  Mostly the air blows just enough under but some fairing shapes i have to pretect eyes.  The incoming air (0.5M diameter fan at very high speed) is pointed at the radiator but a portion hit the ramair intakes.
Nobody i know maps aftermarket racebike ecu's based on manifold pressure or the conditions i am showing here.  With 4 single throttle bodies there is too much pulsing going on for this to be of use.  If there was a large plenum and the pressure sensor was located in this then maybe you could go that way but that is not applicable for any bike i know of.
The acceleration on dyno is faster than on track.  I have some acceleration enrichment enabled but not for the rpm logged at the point on the graph where the black line is.
The acceleration shown is going through the gears on a straight with a quickshifter, similar to what you would see in a drag race so maybe somebody reading this may find it of some small use.
Petrik.  If you like, i can email you the motec map for this bike and the logging so that you can view all the various compensations and analyse the logging yourself.  All the data is contained in there.  You seem to be the few who understands what is happening.

[PetriK]

Havent seen any dynos so far where the fans are effective enough causing the operator to wear goggles, so that is cool  And yep - I dont really know how to read motec logs. Have only used Innovate LM1 so far... when have time could be interesting to read motec logs if the sw is avail easily.

Also I got a feeling that we are talking slightly different topics here. I am not suggesting to use manifold pressure for tuning the WOT or high power areas, this is nor the way how Suzuki has designed the ecu. Manifold pressure is only used for very small TPS positions to adjust the fuel. Well - saying that regardless of the load the manifold pressure is used to determine if PAIR should be on or off (in EU models) at full TPS range from 0-100%.

The reason why I am interested in about ambient pressure with logs that were presented: The ambient pressure is the single most important contributing external factor to the injector pulsewidht even at WOT. Without knowing how ambient pressure sensor is calibrated or mapped etc. the AFR can be anything.

For example: Busa atmospheric pressure sensor effect to the pulsewidth @ around 8000rpm, 3rd gear
3.15V = 10.2ms
3.27V= 10.8ms
3.5V = 11.5ms
The spec says that 0-600m means 3.1-3.6V sensor readings which may vary also according to the temperature. That is almost 10% of pulsewidth difference. Unfortunately I dont have a datasheet to have exact pressure readings but if that sensor is calibrated incorrectly or if there is big difference in readings it will cause big AFR differences.

In Busa the intake air difference of 4C degrees has almost no effect to the pulsewidth. Within operating range of 20-50C I can measure only < 0.01ms differences into pulsewidth @ WOT (or any other TPS position, of course I may have a problem with the test setup.).

This on the other hand puzzles me as the 4C temperature change to air density should be same as difference between 990mbar (low pressure) and 1010mbar (sunny nice day) air pressure (depending on dew point and if I got my math right, almost feels like my testing bench is not working properly) - but maybe the Suzuki engineers noticed that intake air temperature is too dependent on the engine warming the sensor up that they could only rely on external air pressure sensor ? Also the injector pulsewidht is also more dependent on coolant temperature sensor operating range values than intake air temperature sensor. (I know this because I have tested this on the desktop workbench - but like said above, I also may have something incorrect with the workbench setup. On the level I do things errors are very possible.)

And then getting back to the original discussion. The Suzuki ecu calculates the ram air pressure compensation factor based on RPM and gear. The intake air pressure sensor has nothing to do in that game. Anyhow the ram air pressure compensation factor is then multiplied by ambient air pressure factor amongst many other things. Therefore when estimating the ram air compensation correctiviness from AFR values we need always to know the ambient pressure sensor readings.

So because of the above I would not use the information provided on those images to decide on how ram air compensation works or not work.

Saying this I do not have a clue how motec works and it may be completely different ballgame with motec...

[enginetuna]

Yes my fan is pretty strong.  I can do heavy load testing on most bikes and they do not get too hot, especially this time of year.  I can have the headers glowing bright orange on a 30-second sweep test and water and oil temp are within reason.
You can download the motec ecu manager and log analysis software for free.  Motec is awesome kit.  Cost to map a superbike is about 15 times the price of a powercommander custom map but once its done you have something really special.
I will try and put an airbox pressure log on a bike this year.  Won't be a busa, maybe a gsxr600/1000 or an r6.
I don't need to bother with accurate compensation tables, as the maps get trimmed manually each session at the track if needed.
Good luck with the ecu hacking and creating new tables.  Takes me forever to get it all right and i've got a familiar and user-friendly interface.

[gazza414]

ET, if you are going to log air box pressure ..and you have a few xtra sensors can you place them in different locations ? and see if indeed there are local variations ? I had 1 in the rear of my land speed bike and I saw some wild fluctuations.

[PetriK]

Maybe this is getting a bit too techy - but there is now something I dont anymore understand. There is interest to measure the airbox internal pressure - where as I am mainly interested in about the airmass velocity through the system ? I.e. if the engine breathes better with higher gas velocity there should not necessarily be increased airbox pressure - on the other hand, there should always be higher gas velocity present ? To me Ramair is not about pressure, its about increased velocity - unless the TPS is 0%.

So far measuring the airbox pressure (for me) has not yielded useable results due to the intake pulses existing within the box causing resonanse, i.e. pressure waves going through the box. Pressure pattern inside the box (or intake manifold) has anyhow given useful information about e.g. misaligned intake cam. Also small things like just leaving out the ramair tubes during dynoing made the bike to loose 5-7hp top end outlining the importance of keeping the velocity for full ramair tube lenght.

Is there something I am missing to understand because of lack of experience and lack of repetiive logger data ?

[enginetuna]

I wouldn't look at the ramair system and tubes as a means of ramming air in but more as a way of reducing restriction and providing a clean air supply.  The size and volume of this system is very critical on the delivery.  I have done a fair bit of dyno testing with airboxes and on this one big airbox with a specific high pressure air feed sealed into it, the fiberglass airbox lid would bow outwards and then suck in a couple of times climbing through the rpm range.  I was shocked.  Opened my eyes to what goes on. 
You might also want to think of the airbox and tubes as a damper.

[entropy]

leaving out the ramair tubes during dynoing made the bike to loose 5-7hp top end outlining the importance of keeping the velocity for full ramair tube lenght.

We saw exactly this same loss with my built ZX12 on JohnnyCheese dyno a couple years ago.

pretty weird.

[GenII Busa]

You guys are making this way more complicated by trying to blow air into the ram-air ducts on the dyno to simulate ram-air pressure and trying to measure the airbox pressure.  Without ram-air, the airbox pressure will always be below ATM pressure when on the dyno.  I believe at around 60 or 70 mph on the road is when the airbox starts building pressure up over ATM pressure.  Also, the closer the pressure sensor is to the throttle body intake tubes, the more turbulent and the more pulsations there will be in that local area.

If you just add 0.5 A/F points richer at the top end without trying to simulate any road airflow, then it's going to be pretty damn close when on the road.

[Busa Quick]

You guys are making this way more complicated by trying to blow air into the ram-air ducts on the dyno to simulate ram-air pressure and trying to measure the airbox pressure.  Without ram-air, the airbox pressure will always be below ATM pressure when on the dyno.  I believe at around 60 or 70 mph on the road is when the airbox starts building pressure up over ATM pressure.  Also, the closer the pressure sensor is to the throttle body intake tubes, the more turbulent and the more pulsations there will be in that local area.

If you just add 0.5 A/F points richer at the top end without trying to simulate any road airflow, then it's going to be pretty damn close when on the road.

 It would be nice to see the charts or info that makes your decision of .5 A/F the right one. I am not arguing with you but, the conversation is how to get exact numbers using recorded data.

Mark

[quizesilver]

so for dyno run
we juz need to tune it to abt 0.2 to 0.3 richer then std?
for all gear ?

[GenII Busa]

You guys are making this way more complicated by trying to blow air into the ram-air ducts on the dyno to simulate ram-air pressure and trying to measure the airbox pressure.  Without ram-air, the airbox pressure will always be below ATM pressure when on the dyno.  I believe at around 60 or 70 mph on the road is when the airbox starts building pressure up over ATM pressure.  Also, the closer the pressure sensor is to the throttle body intake tubes, the more turbulent and the more pulsations there will be in that local area.

If you just add 0.5 A/F points richer at the top end without trying to simulate any road airflow, then it's going to be pretty damn close when on the road.

 It would be nice to see the charts or info that makes your decision of .5 A/F the right one. I am not arguing with you but, the conversation is how to get exact numbers using recorded data.

Mark

The best way to get exact number with recorded data is to put an on-board wide band O2 sensor and data logger on the bike and go tune it on the road.  Of course, that's too expensive and complicated for most.  The 0.5 A/F richer on the dyno was verified by Motorhead many moons ago.  If someone with an on-board O2 data logger tuned the bike on the road to be perfect and then ran it on the dyno with zero ram-air, then it's going to be slightly richer on the top end when on the dyno.

Besides, IMO 0.5 A/F off at near redline in 6th gear probably isn't going to be noticeable except for guys strictly running for top end speed contests.

[GenII Busa]

so for dyno run
we juz need to tune it to abt 0.2 to 0.3 richer then std?
for all gear ?

I believe that is for 6th gear -- but it's more like 0.3 to 0.5 richer A/F.  If you use lower gears then it won't be quite that much.  In 6th gear is when the ECU is compensating for the ram-air the most since at X RPM in 6th gear makes the bike go faster than say X RPM in 4th gear.  The faster the bike is going, the higher the ram-air pressure and the more fuel compensating there is.