Secondary Butterflies removal review

[fallenarch]

I think the Gen II was designed to get more top end power out of the engine than the Gen I was. I think they added the secondaries because they compromised too much low end grunt to get the top end HP numbers they were looking for. It's really a little crazy to think they went to the expense of secondaries just to take a little edge off a bike like the Busa simply for safety when the bike goes 186 mph and pulls your arms out of the sockets!

The secondaries do make the bike more drivable but if you want to improve throttle response my vote goes for a good full exhaust and a good filter.

 

[Draco1340]

I have tried to keep out of this thread, but to no avail ???

When the Gen II first came out, we tried launching it at the dragstrip without secondaries, and the result was disastrous. Unless you come out at 8k, the motor would bog bad, and then hit hard resulting in spin or lift. Best 60' I could muster was a 1.45 and that was slipping the clutch hard. Put the plates back in, and the 60' came right back down to high 1.3s. The great thing about this motor is that you can get the cluch out QUICK at a lock rpm of 7500 or so, and then let the motor torque you through first nice and smooth. Take the plates out and its like riding a 2 stroke.

 

[mungybear]

Gen 1 Busa: 46mm throttle bodies, no secondary throttle plates;

Gen 2: Bigger motor, more compression, better flowing head, SMALLER (44mm) throttle bodies, secondary throttle plates.

ZX14: 44mm throttle bodies, secondary plates.

The ZX14 keeps its STPs closed up to 6,000 rpm at 100% throttle, which is why removing them shows clear gains on wide open dyno pulls;

The Gen 2 only keeps them closed in 2nd and 3rd gear, which is why it does not show up on wide open throttle pulls on the dyno.

To say that the Gen 2 cannot handle its "big" throttle bodies, and the STPs are there to increase velocity and help the motor transition is ridiculous, since the Gen 1 has bigger throttle bodies and has no problem, even with a smaller motor, lower compression, and its early cylinder head. Again, removing the STPs requires remapping on both the Gen 2 and ZX14 in order to realize the gains. I haven't tried this on either bike with stock pipes, and am not sure I would recommend it.

We would need 3rd gear runs with a Gen 2 on a dyno to see the differences.

Do the math . . .

Again, what about just remapping....leaving the stp's in position and using the values set out in petricks ecu editor from gear 4. Then SURLEY you will have the best of both worlds???? Has anyone done this yet? or am i gonna have to do it myself???

If you guys want me to do it, i will, but you may have to wait til she's run in and had the first service, and then i need the bits n bobs to do it.

 

[Dozerdriver]

I have tried to keep out of this thread, but to no avail ???

When the Gen II first came out, we tried launching it at the dragstrip without secondaries, and the result was disastrous. Unless you come out at 8k, the motor would bog bad, and then hit hard resulting in spin or lift. Best 60' I could muster was a 1.45 and that was slipping the clutch hard. Put the plates back in, and the 60' came right back down to high 1.3s. The great thing about this motor is that you can get the cluch out QUICK at a lock rpm of 7500 or so, and then let the motor torque you through first nice and smooth. Take the plates out and its like riding a 2 stroke.

This is why I put mine back in... exactly what would happen with mine. Mine was tuned with the plates in so I am not sure if it could be adjusted not to do that but for me it wasn't what I wanted.

 

[smithabusa]

I have tried to keep out of this thread, but to no avail ???

When the Gen II first came out, we tried launching it at the dragstrip without secondaries, and the result was disastrous. Unless you come out at 8k, the motor would bog bad, and then hit hard resulting in spin or lift. Best 60' I could muster was a 1.45 and that was slipping the clutch hard. Put the plates back in, and the 60' came right back down to high 1.3s. The great thing about this motor is that you can get the cluch out QUICK at a lock rpm of 7500 or so, and then let the motor torque you through first nice and smooth. Take the plates out and its like riding a 2 stroke.

as always you bring real world data to the plate

 

[xchief1320]

Using ECU Editor I set my STP table to all 94's in 1st-6th just to see if it made a difference.
I didn't like it, it lost a lot of off idle torque. It did seem to help mid range a little, but no difference after 6k or so since after that the plates are wide open then anyway.
I bought the Busa for the tq they make. With the plates wide open all the time the bike felt like a 600 until 4500 or so, Then it took off. Was not smooth at all..

I guess it depends on your riding style if you'll like it or not.

 

[mungybear]

Using ECU Editor I set my STP table to all 94's in 1st-6th just to see if it made a difference.
I didn't like it, it lost a lot of off idle torque. It did seem to help mid range a little, but no difference after 6k or so since after that the plates are wide open then anyway.
I bought the Busa for the tq they make. With the plates wide open all the time the bike felt like a 600 until 4500 or so, Then it took off. Was not smooth at all..

I guess it depends on your riding style if you'll like it or not.

So that makes it identical to removing the butterflies it seems.

Did you also try matching the 2nd and 3rd gear to 4th?
Posted via Mobile Device

 

[jeepinocala]

I am glad to see alot of expeirenced people showing why the secodaries are a good thing it is frustrating to see people who think just removing parts will make it go faster now sure emmision control parts may help but I think suzuki pretty much knew what they were doing when they built this bike.

 

[POWERHOUSE]

I am glad to see alot of expeirenced people showing why the secodaries are a good thing it is frustrating to see people who think just removing parts will make it go faster now sure emmision control parts may help but I think suzuki pretty much knew what they were doing when they built this bike.

What everybody seems to be missing is that the stock bike has fuel mapping that accounts for the secondaries being partially closed. You can't just remove them, or alter the STP mapping without augmenting the fuel in some way. Just removing the secondaries will make the bike slower - you have to add fuel to account for the change - just like every other change. Only then will you see benefits . . .

 

[bradbusa]

What everybody seems to be missing is that the stock bike has fuel mapping that accounts for the secondaries being partially closed. You can't just remove them, or alter the STP mapping without augmenting the fuel in some way. Just removing the secondaries will make the bike slower - you have to add fuel to account for the change - just like every other change. Only then will you see benefits . . .

that's exactly the point i was trying to make originally, in my response to the original post - which claimed benefits on removal only.

i didnt realize at first that the 1st gen busa had larger throttle bodies? you are right about that though. i agree with you, however, im sure suzuki tuned the engine to run properly without them(timing, fuel..etc)
and i assume that with the same care and attention the 2nd gen can be tuned similarly.

 

[Draco1340]

What everybody seems to be missing is that the stock bike has fuel mapping that accounts for the secondaries being partially closed. You can't just remove them, or alter the STP mapping without augmenting the fuel in some way. Just removing the secondaries will make the bike slower - you have to add fuel to account for the change - just like every other change. Only then will you see benefits . . .

I'm a racer and a tuner.
I did tune it.
proper A/F won't fix low flow velocities.
It doesn't work on the track... For me.

 

[POWERHOUSE]

I'm a racer and a tuner.
I did tune it.
proper A/F won't fix low flow velocities.
It doesn't work on the track... For me.

Yes, I understand that - but all of my experiences with this mod and tuning have been positive. The low flow velocity thing - the Gen 2 having smaller throttle bodies, and the Gen 1 having larger throttle bodies - doesn't seem to make any sense, since the Gen 1s have no problem with larger throttle bodies.
Most Gen 1s will wheelie freely when the throttle is wacked open down low.

Draco, it makes me wonder if something else Suzuki did is affecting all of this. Timing maps, different cams, etc? The next 08-09 I get my hands on I think I will try unifying fuel and ignition maps- and in conjunction with some STP map tweaking (without removing them), I will make back to back 3rd gear pulls to see if we can get to the bottom of this. At this point, I think the gremlin some are experiencing is lurking somewhere in that ECU, 1-3rd gear . . .

 

[2Wheels2Live]

I agree Frank, I think suzuki used several ways to soften the low end throttle response for safety reasons, part stp's, part ecu tricks etc. Whatever it takes to keep us from looping our bikes I guess At least the first gen busa was just some timing retard....this seems much more complex ??? My 14's secondary removals were a cinch, and gave spectacular results with just a mapped power commander, and that was on a bone stock bike. It just got better with mods. I think suzuki took their safety procedures much more seriously though I assumed just pulling the stp's and a power commander would be the ticket on the 2nd gen busa, but maybe its not that easy? From what I'm hearing now, I might be inclined to just leave them in

 

[smithabusa]

even gen 1 timing retard is a very mis-understood deal as well, timing is only retarded at very low rpm, very low throttle, has nothing to do with maximum performance at wide open throttle.

 

[Amode]

I made a comment about the vacum area on the o8's. I would also like to send Petrix a E mail on implementing Pulse with fuctions for larger injector's. i will call frank on friday and talk to him about these settings. I have tryed a number of settings and some what understand this thing slowly. i like this thread a lot of good info will come out of this.

 

[BiggDaddyBusa08]

Draco, it makes me wonder if something else Suzuki did is affecting all of this. Timing maps, different cams, etc? The next 08-09 I get my hands on I think I will try unifying fuel and ignition maps- and in conjunction with some STP map tweaking (without removing them), I will make back to back 3rd gear pulls to see if we can get to the bottom of this. At this point, I think the gremlin some are experiencing is lurking somewhere in that ECU, 1-3rd gear . . .

Hey Frank I could offer you my 08 for dyno testing on this subject. I would be able to do it at the end of the month.

 

[mungybear]

i originally thought the restrictions in all gears were removed in ecu editor, but having done it whilst on a dyno, it proved that only 6th top speed restriction was removed. And yes we ticked the right boxes. I may have the graphs if you are interested.
Posted via Mobile Device

 

[Draco1340]

Yes, I understand that - but all of my experiences with this mod and tuning have been positive. The low flow velocity thing - the Gen 2 having smaller throttle bodies, and the Gen 1 having larger throttle bodies - doesn't seem to make any sense, since the Gen 1s have no problem with larger throttle bodies.
Most Gen 1s will wheelie freely when the throttle is wacked open down low.

Draco, it makes me wonder if something else Suzuki did is affecting all of this. Timing maps, different cams, etc? The next 08-09 I get my hands on I think I will try unifying fuel and ignition maps- and in conjunction with some STP map tweaking (without removing them), I will make back to back 3rd gear pulls to see if we can get to the bottom of this. At this point, I think the gremlin some are experiencing is lurking somewhere in that ECU, 1-3rd gear . . .

Drag racing is all about 1st gear. Many think its about top end power, but most of your ET is spent getting out of 1st gear. A smooth predictable torque curve is what gets you to the 330'. Lets put some numbers to this hypothesis.

My stock motor makes approximately 210 ft lbs of torque max without spray in first gear. My overall gear ratio is (primary x 1st gear x final drive ratio). For me that's (1.596 x 2.615 x 2.687) = 11.21 gear ratio. That means that coming out of the hole in first gear, my tire sees 210 x 11.2 = 2350 ft lbs of torque. Our tires have a radius slightly over a foot, so basically the bike sees 2300 pounds of thrust. If the motor torque surges even by 5%, the torque at the rear tire changes by more than 220 ft-lbs! The thrust changes by the same amount - 220 lbs. Something has to give when the chassis sees a shock of over a third of a G force, so the front end comes up, or the tire blows away. You can design a chassis to handle acceleration, but you can't handle shock. Smooth acceleration is fast. Shock may FEEL fast (I remember my first H2 2-stroke), but it isn't.

 

[crawler]

Drag racing is all about 1st gear. Many think its about top end power, but most of your ET is spent getting out of 1st gear. A smooth predictable torque curve is what gets you to the 330'. Lets put some numbers to this hypothesis.

My stock motor makes approximately 210 ft lbs of torque max without spray in first gear. My overall gear ratio is (primary x 1st gear x final drive ratio). For me that's (1.596 x 2.615 x 2.687) = 11.21 gear ratio. That means that coming out of the hole in first gear, my tire sees 210 x 11.2 = 2350 ft lbs of torque. Our tires have a radius slightly over a foot, so basically the bike sees 2300 pounds of thrust. If the motor torque surges even by 5%, the torque at the rear tire changes by more than 220 ft-lbs! The thrust changes by the same amount - 220 lbs. Something has to give when the chassis sees a shock of over a third of a G force, so the front end comes up, or the tire blows away. You can design a chassis to handle acceleration, but you can't handle shock. Smooth acceleration is fast. Shock may FEEL fast (I remember my first H2 2-stroke), but it isn't.

Exactly why sliders are so deadly at the track. Smooth is fast.

 

[Amode]

Exactly why sliders are so deadly at the track. Smooth is fast.

I talked to Frank today, After our conversation i think after he gets a Gen 2 and on the Dyno he will solve the issue about leaving the STP's in or taking them out.

Chuck