dyno results w/ air kit

[DanB]

DOH!

I got the Evo air kit in the hopes of minimizing the big torque dip I've got at 5k. I was super anal about ensuring only filtered air gets into the engine, ran a 2" wide strip of adhesive-backed foam rubber around the underside of the tank, lining up with the gasket. She's (air)tight I did leave the stock insulation in place, it seals to the evo gasket in a couple of places as well. Also figured the insulation might "soften" any resonance-induced torque variations. I also removed the resonance tube thingie in the ram-air collector below the main airbox at this time.

Previous dyno results:
Original baseline configuration: 2003 Tuono, Aprilia Ti EVO can (and chip?)
peak 68.7 lb-ft @ 7000, 110.3 hp @ 9400 (avg. A/F ~12.4:1)
dip 51.2 lb-ft @ 5150 (locally rich, A/F = 11.95:1)

removed short "restrictor" tube at inlet of main airbox:
peak 68.6 lb-ft @ 7150, 109.8 hp @9400 (avg. A/F ~12.4:1)
dip 52.9lb-ft @ 5200 (locally rich, A/F = 12.25:1)

Dyno results after air kit (and removal of resonance tube thingie):
peak 69.5 lb-ft @ 7050, 111.3 hp @9400 (avg. A/F ~12.0:1)
dip 51.2 lb-ft @ 5100 (locally rich, A/F = 11.65:1)

In all, not much change, slightly more peak power but the dip is back to it's original low. Interestingly, the A/F mixture is a smidge *richer* with the air kit, by about 0.4. I would've figured it to make the mixture leaner if anything.

We did another run with the cooling fans aimed at the intake scoops, and found some mo' torque and power:
peak 70.1 lb-ft @ 7150, 112.1 hp @ 9500 (avg. A/F ~12.2:1)
dip 52.0 lb-ft @ 5100 (locally rich, A/F = 12:1)

I'll post results as soon as I figger out how, picture's worth a thousand words, eh?

So, the quest for torque at 5000rpm continues


Looks like full duals are in my future. Wonder if there's any way to graft those neat-o lookin' brushed blue cans from the '04 Mille onto my bike...

[clarkie49]

12.2:1

that thing is drowning in fuel, get a powercommander and get them to run a custom map, the dip could be from being overly rich...or lean

[DanB]

Can it be that the "air kit" has actually reduced the amount of air the motuh's gettin? WTF happened?

I agree it's a bit rich, but I wonder how much ram-air has to do with it. With cooling fans pointed in the intake scoops (figger maybe equivalent to 40mph?), the A/F went leaner, from 12.0 avg to 12.2. Wonder what it is at actual speed on the road in 4th gear? Also, looking at some previous 3rd gear runs, they're considerably leaner, particularly at low-mid revs, apparently the map takes road speed into account.

Mixture goes from ~12.7:1, to 12:1 at the dip, back up to 12.7, then gets progressively richer toward the top end all the way to 11.8:1.

But, judging from the leaning of the mixture I observed at the dyno today just from pointing cooling fans at the intake ducts, I wonder how much leaner the top end would be at-speed. Is anybody tuning to take this into account? I know at the factory they have these powerful fans that vary w/ dyno speed to simulate the actual draft at speed.

There's a big obvious rich spot right at the torque dip. I still think it's an artifact of volumetric efficiency at that rpm. i.e., I *think* that even if I get the mixture right at that point, the underlying problem of sucky aspiration due to cam/intake/exhaust will still give a big torque dip there.

DAMNATION!

[clarkie49]

you want to 'shoot' for 13:1 ranging from 12.8:1 to 13.2:1 a/f

the bike will compensate for the air pressure to some degree, otherwise it would be super lean at speed

[bluestreak]

Not to agrue, just my view on the above comments.

Clarkie is right in refference to AF ratio of about 13.1, That's a good theorectical target, but you have to play with it to determine what AF it needs for best power for your altitude and average temperature and humidity. In Houston where the air is thick, bikes like it on the rich side of 13.1. (My Honda VTX likes it at 12.8) I like to dyno the bike increasing the fuel until power falls off, then do the opposite towards a lean AF ratio until power falls off. Then you can better determine what the bike needs for peak power as it moves thru the rev range. Also, don't put too much into one dyno pass. Make several and take the average of all of the runs for a specific change you have performed. There are too many variables that can alter results on a pass, so get an average test result that you can believe and have confidence in. I do a lot of testing in my day job and statistical averages are they only way to be sure of a result.

Our bikes can not compensate for MPH speed variation (to take advantage of ram air effect, IF or when it actually occurs) unless the ECU compensates for actual MPH speed increase or the bike has a barametric pressure sensor which I don't believe it does. If it has one please let know. The ECU does compensate for outside temprature thru the brass sensor located on the front fairing left side.

In regards to the ram air effect, it is practically non-existant on the Tuono because the air scoops are not sealed to the air box. It is really just operating at atmospheric pressure, so no benifit there. There is a post that explains how to seal the scoops in oder to make them work, but I don't believe there is enough frontal scoop area to really make a difference. But I don't see how it could hurt either.

Make sure your fuel pressure is correct. It will affect the AF ratio thru out the RPM curve.

I would suggest removing the foam pad on the underside of the tank as per the instructions. It is now exposed to the air entering the engine and is above the throttle bodies. When the foam begins to break down ( and it will eventually with the process sped up due to exposure to gasoline vapors ) it will pass into the engine. Not a good thing.
I am annal about making sure only clean air gets to the engine and I too was worried about the intergity of the seal on the race air box, but after running it now for about thousnd miles and periodicly checking it, I'm convinced the furnished seal is adequate.

[dbl_aitch]

Originally posted by clarkie49
12.2:1

that thing is drowning in fuel, get a powercommander and get them to run a custom map, the dip could be from being overly rich...or lean

It seems rich in general throughout. If a person had a fuel pressure regulator mounted, couldn't he just lower the pressure a bit? Or would that negatively impact fuel vaporization?

Seems like a cheap, easy fix...

[DanB]

Getting the mixture closer to 13:1 is certainly part of the plan, but my concern now is more gross behavior. i.e., big torque dip, big corresponding rich spot. At this point it's not worth doing more than three runs at a go, because the gross behavior is obvious.

Originally posted by bluestreak
Our bikes can not compensate for MPH speed variation (to take advantage of ram air effect, IF or when it actually occurs) unless the ECU compensates for actual MPH speed increase or the bike has a barametric pressure sensor which I don't believe it does. If it has one please let know.

I wouldn't think it has a pressure sensor, but it surely would be no problem for the ECU to adjust fuel delivery based on mph.

In regards to the ram air effect, it is practically non-existant on the Tuono because the air scoops are not sealed to the air box. It is really just operating at atmospheric pressure, so no benifit there. There is a post that explains how to seal the scoops in oder to make them work, but I don't believe there is enough frontal scoop area to really make a difference. But I don't see how it could hurt either.

Your Tuono must be different from mine. My scoops are sealed to the outside of the frame, and the ram-air collector rubber ducts on the inside are molded to fit snugly inside the frame openings, with a flange around the perimeter. Granted they're not gonna hold a seal at 5psi, but even assuming you get 100% of stagnation pressure, that's less than 0.4psi at 150mph.

Pointing the dyno fans at the scoops did affect the A/F readings and power/torque output.

Make sure your fuel pressure is correct. It will affect the AF ratio thru out the RPM curve.

First wanna get a handle on the gross behavior. The mixture is all over the place, starts ~12.8:1, goes rich, to 12:1, back up to 12.7:1, then gradually gets richer, all the way to 11.8:1 at redline. Again, I think that part might be to compensate for ram-air at high speeds (4th @ 10k =~125mph)

I would suggest removing the foam pad on the underside of the tank as per the instructions. It is now exposed to the air entering the engine and is above the throttle bodies. When the foam begins to break down ( and it will eventually with the process sped up due to exposure to gasoline vapors ) it will pass into the engine. Not a good thing..

I'll keep an eye on it.

I am annal about making sure only clean air gets to the engine and I too was worried about the intergity of the seal on the race air box, but after running it now for about thousnd miles and periodicly checking it, I'm convinced the furnished seal is adequate.

On my installation, the back edge of the gasket wasn't making contact with the fuel tank, over a length of ~2". Also, at the front where the gasket doubles over there were gaps on either side. So I went nuts with the foam tape.

[clarkie49]

bluestreak - yeah, 13:1 is a generalisation, but it will be kinda close.

check the fuel pressure, i am sure it will be in the 50-52psi range, and then you can buy the evo pressure reg kit and reduce the pressure to 49psi where it should be for the Tuono

[steeba]

Ok, now that we've gotten thru fuel pressure and air scoops...just had my '03 Tuono air boxed and (dealer said that this was a normal occurrence with the addition of the Evo) upon deceleration from high rpm's, I'm getting a pop or backfiring situation...normal or maybe too rich ? Aaargh !

[clarkie49]

check that the small vacuum lines on the left side of the throttle bodies arent cracked or split.

'sometimes' when they are split the bike wont idle as well as it should and it will 'hunt' around, it can also cause backfiring on decel

[steeba]

that's a roger, clarkie...but...regardless of whether the lines are cracked or split, should the addition of the airbox, under normal conditions, cause the backfiring (per the dealer's, "it's ok", comments) ?

-s

[clarkie49]

it hasnt on any of the ones i have installed, but that doesnt mean it doesnt happen.

check with Ken @ Evoluzione

[bluestreak]

The addition of the air box will lean the engine slightly but not enough to hurt anything. Your bike is probably on the lean side to begin with, so the addition of the air box has leaned it out enough to pop on deceleration. FP chip or PCIII will fix it.

To acheive the potinial of the air box you'll need to open the exhaust and re-map the fuel as stated above.

[DanB]

See above, the air kit ENRICHED my mixture. Puzzlin, eh? Bike runs fine after the airkit installation, no poppin/backfiring or anything like that. In fact, my backside can't tell a difference at all, and the dyno can't tell much!

This experience has been the exact opposite of the cheap-o "snorkelectomy" on the SV. One free mod to the airbox and $5 worth of jets and shims netted me 9% more midrange and 4.7% more peak power with the SV. With the Tuono I'm out $200, gained 1.5% up top (woohoo!) and LOST 3% at the midrange dip.

I guess it's safe to say the Tuono's stock airbox is a helluva lot closer to being optimized for performance AS-IS than the SV's.