shiphteey
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posted January 30, 2009 03:41 PM
 Edited By: shiphteey on 30 Jan 2009 23:50
Diagnosing and possibly upgrading the fuel system for nitrous.
Well, I've had my 2000 model for 3 1/2 years now (time flies) and its served me well. Ran around the country going a little over 200 and had some fun. Before I even think about going with a big shot of nitrous I wanted to see where I am at now and plan smart, since much of my planning is bound by the thinness of my wallet I'm trying to make the smart moves at the right time.
Presently I run a small dry shot, normally 35-40 hp depending on psi, etc. I've had no problems with it and 93 octane pump gas, a rich map and colder plugs have ensured my motor was ready to run time and again. Somewhere down the line I picked up a used Muzzys Fuel Pump from Matt Sterbator on the board. It seemed to work fine because I do remember having to remap when I went from stock to Muzzys.
I have experimented with slightly larger shots on the dyno to see where duty cycle is on my 00 injectors after receiving them from RC Eng for cleaning. What I have seen is that duty cycle is still considerably high, getting the 90s at maybe a 50 shot. That has me coy about going any further so I decided to check the fuel pump:
I disconnected the fuel lines, spilling a few ounces of fuel as I always seem to in the process.
Undid the 8mm fuel pump bolts from the bottom fo the tank and removed fuel pump after carefully wiggling it around, almost losing my patience in the process.
Note there is no sending unit in my set-up anymore as my cut down tank doesn't give enough clearance for it. No worries, just keep an eye on fuel level before and after runs. Inspected the OEM base of the fuel pump....ahhh...good old Bonneville corrosion!
Careful inspection of the pump reveals the silver pump is a Walbro unit with numbers that verify its the one in the Muzzys. Stock 2000 is gold which I still have.
I am wondering why the duty cycle is still quite high. Stock pump puts out more PSI than the Muzzys but the muzzys is rated for up to 700 HP usage so something else must be causing the high duty cycle. It could be I need to bump up the psi with a fuel pressure regulator (no provisions for that with my current set-up, it will require some modification). Before I go into that I will check/remove the bronze/brass colored housing which holds a fuel filter and install an 8mm rubber hose in its place to see how duty cycle is affected. I will check fuel pressure and check duty cycle with my Innovate LM1 and the dynojet unit on our Dyno to see if there are any variances between the two.
Below is an article Doug Meyer wrote years ago with regards to fuel pumps, specifically addressing the 2000 model's need for a bigger pump if you are significantly increasing HP. In reading the article I came away expecting the pump to "cure" the high duty cycle I see at the 200-210 RWHP figures I've put down on the dyno on nitrous. I think I may need inspecting the built-in fuel filter in the brass housing may permanently damage it (based in its design) but my main focus is getting more fuel to the motor to keep things safe and not run on the ragged edge. Bigger injectors are out of my budget, as is a wet kit so this is the route I'm presently taking.
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Pumps - How they Really Work!!
by Doug Meyer
..First a little about pumps. A pump moves a fluid. It creates a flow with pressure. You can have a lot of flow at a low pressure or a little flow at a high pressure or high flow at a high pressure or low flow at low pressure. Different types of pump designs are best for each of these requirements. Examples- a centrifugal pump like the water pump on your bike creates a lot of flow at a low pressure. A gear pump like the oil pump can create a generous flow at a high pressure. Flow and pressure are generally related in that if you retard the flow, the pressure builds. Allow the flow to increase and the pressure falls. Pumps are spec’ed with a certain flow at a certain pressure. An easy example would be a bucket and a hose. Household water pressure is about 35 psi. Run a hose onto a bucket and you get a fair amount of water in there pretty quickly. Put your thumb over the end and the pressure goes up dramatically, and the flow (amount of water getting into the bucket over a given time) goes down. The “spray” is better, though (remember that). Each type of pump has it’s limitations. Pinch off the flow in a centrifugal pump and it just spins freely with no problem (and no pressure). Restrict the flow in a good gear pump and the non compressibility of the fluid can build pressure until something breaks or blows up. That’s why there are pressure relief valves in oil systems. Pumps have a flow vs. pressure efficiency curve. Turn a pump too slow and flow is very small or zero, ask it to flow too much and pressure begins to drop- it can’t “keep up”, it cavitates or can’t move the fluid fast enough to satisfy the requirement and the pressure drops.
The fuel pump in a ZX-12 is a kind of hybrid between a centrifugal vane pump and gear pump, called a friction pump. The electric motor (which is cooled by and submerged in the fuel) spins a thin plastic disc rimmed with small “teeth” like a very fine gear. This disc spins in a small plastic housing. The fuel goes to the periphery of the spinning wheel, is “grabbed” by the small teeth, spun around and forced out of the housing. It’s not exactly a positive displacement pump like a gear pump, but it’s not exactly a centrifugal pump either. It’s a little of both. Problem is, it has a pretty small sweet spot of good flow and pressure. But, that shouldn’t be a problem because a stock ZX-12 has a very predicable fuel requirement, and as you point out, the pump always spins the same speed. The pump NEEDS only to provide enough fuel to create no more than about 180 hp at no less than 47 psi. The pump does that just fine, but it does that at the very high end of it’s efficiency curve. Ask it to provide enough fuel to create 200 hp and it can barely keep up. It can do it, but let it get worn or let the fuel get hot lowering the vapor pressure, or let the injectors get “sloppy” or let any number of other factors degrade it’s performance and the flow (and pressure) drops. Less fuel means a leaner mix and soon, detonation and broken parts. How much fuel are we talking about here? The answer lies in something called Brake Specific Fuel Consumption (BSFC), which is expressed in pounds of fuel burned per horsepower per hour. Gasoline contains a pretty much fixed amount of heat energy that when “liberated” through burning is mechanically converted to horsepower. In a modern four stroke that amount is fairly constant at between .42 and .5 pounds of fuel per horsepower per hour. As an example let’s pick .5 ‘cause the math is easy. 180 hp would require .5 pounds of gas for each of 180 the hp or 90 pounds per hour (PPH). A gallon of gas weighs about 6.2 pounds so that’s 14.5 gal per hour or .24 gal. per minute at wide open. I’m told by Kawasaki engineers that the stock ZX-12 pump is a .65 liter per minute pump at 45 psi continuous. That converts to .21 gal per minute, 12.7 gallons per hour or 79 PPH. Ask it for more and you might not get it. Interestingly enough, that fuel delivery is enough for about 160 hp at .5 or at a more realistic .47, 164 hp. Guess what the average stock ZX-12 (2000/01) makes for HP? So, why not put in a different pump, one that is sized to deliver much more fuel at 50 psi. That way you are unlikely to be able to approach the point where it can’t “keep up”, where the pressure might drop a bit. The Muzzy pump flows over 350 PPH at 50 psi., enough for 700 hp. More than you need? Sure. But on a modified ZX-12 the stocker may very well be less than you need. There really isn’t anything in between that fits the physical mounting requirements.
A few words about injectors and pressure may be in order here. An electronic fuel injector is a nothing more than an electromagnetically operated solenoid valve. There are two basic varieties, “high impedance” and “low impedance”. In a high impedance injector, a current is sent to the magnetic coil in the injector which lifts a plunger and holds it open for a set period of time (in thousandths of a second or milliseconds) then cuts off and lets it close. Low impedance injectors are a little more sophisticated. They use a high current to quickly open the injector then a lower current to hold it there until closing. Better, but the “driver” circuitry and injectors are more expensive. The “open time” is expressed as a percentage of 100% (always open) and is called the duty cycle. A duty cycle of about 80% is preferred. Most OEM systems (including the 12) use the low impedance injector design. When you more flow from the pump, the only way to increase the fuel to the engine is to lengthen the injector duty cycle. A drawback to this is that the longer you hold a low impedance injector open, the longer the (high opening) current is flowing through the coils in the injector, creating electrical resistance and heat. This is a bad thing for the injector’s health. Also, the longer you have the injector open the more you put the pump into the high flow, high pressure corner of the pump’s output curve. What might help this? How about more fuel pressure? That would flow more fuel through the injector in a shorter time. That additional pressure will also make a better “spray” (see bucket example above). The pressure flow relationship is not linear. It takes four times the pressure to get two times the flow through a constant orifice. Remember, flow through an orifice is volume over time and the duty cycle controls the time. To increase the fuel flow needed on the ZX-12 when raising the power from 165 to 200, would require an 8% increase in flow through the nozzles. If it were to be done with pressure alone, without changing the duty cycle, that would take an increase in pressure of 36%. On a stock system that would necessitate an increase of fuel pressure up to 61 psi., something the stock pump is clearly not up to. Again, the “bigger” pump will allow for more fuel to be pumped at a given pressure. Increase the duty cycle (orifice size) and the pump can “keep up”.
All this talk about fuel flow and quantities makes me think about how easy it is to determine these numbers now that we have electronic fuel injection. Back in the day, to measure fuel flow mechanically we used “turbine” flow meters that put a signal to a digital indicator. WAY back in the day we actually ran a carefully measured (by weight) amount of fuel over time on the dyno and measured the consumption to figure out the BSFC. Now days it’s real easy. An injector is rated for a certain amount (in cc’s) of fuel flow at a certain pulse width (in milliseconds) do the math and you get an accurate measurement of the fuel per “squirt”. You get one squirt per injector every other revolution (1/2 the rpm). Do a little more math and you know exactly how much fuel you are using at a given rpm. Do this on a dyno, and you know how much fuel per hp and you have the BSFC.
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A.
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shiphteey
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posted January 30, 2009 07:46 PM
Something else occured to me while thinking it over and talking with a pretty knowledgable friend. The duty cycle figures I'm going by are what is displayed on my laptop while the bike is being dynoed on nitrous. The laptop is plugged into the serial port of the PC3R...and this recording of duty cycle could be flawed and significantly off. What I plan on doing now is reassembling everything back the way it was and comparing the duty cycle I see on my logger to that on my laptop while the bike is run WOT on spray up top.
I should be able to post the results early next week. Fingers crossed! I'm hoping the pc3 is "reading" a higher duty cycle then the logger is "actually" reading.
A.
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KZScott
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posted January 30, 2009 08:54 PM
Ali, cheap and easy way to bump fuel psi on the A bikes. crush the regulator. it works similarly to shimming the oil pump. you can test to see what pressure it opens at by using compressed air. crush a tiny bit, check, crush a tiny bit recheck ect ect till its as high as you want. crushing it basically is compressing the spring a bit, like shimming it. im thinking 60 psi would be a good place to set it.
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01 ZX-12R 8.84 @ 156.3 no bars, DOT tires. Pump Gas, NA.... turbo 8.47 @ 164.
00 ZX-12R 8.62 @ 165.2 no bars, slicks, Pump Gas, 55 shot.... turbo 8.32 @173
00 ZX-12R Fastest NA Kawasaki in the world 1: 222.046 1.5: 226.390 Loring AFB
00 ZX-12R street turbo 1: 227.9 1.5: 234.1 Loring AFB
00 ZX-12R LSR turbo 1: 263.1 1.5: 266.5 Loring AFB Worlds fastest ZX-12R
CMG Racing RCC Turbos
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rgeorge
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posted January 30, 2009 08:56 PM
Ali, the PC3 controls the fuel by adjusting the duty cycle. It knows what is happening.
Your numbers are similar to what I saw and it convinced me to switch to a wet kit.
Keep in mind that the ecu will increase the duty cycle even more with ram air effects.
Have you installed a gauge to verify fuel pressure? The muzzy pump is supposed to be 50psi right?
Did RC blueprint the injectors? what were the flow numbers?
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KZScott
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posted January 30, 2009 09:02 PM
even though the muzzy pump is 50 psi (9 psi higher than stock) the regulator is still opening at 41 psi. the fuel pressure wouldnt be higher than what the regulator opens at.
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01 ZX-12R 8.84 @ 156.3 no bars, DOT tires. Pump Gas, NA.... turbo 8.47 @ 164.
00 ZX-12R 8.62 @ 165.2 no bars, slicks, Pump Gas, 55 shot.... turbo 8.32 @173
00 ZX-12R Fastest NA Kawasaki in the world 1: 222.046 1.5: 226.390 Loring AFB
00 ZX-12R street turbo 1: 227.9 1.5: 234.1 Loring AFB
00 ZX-12R LSR turbo 1: 263.1 1.5: 266.5 Loring AFB Worlds fastest ZX-12R
CMG Racing RCC Turbos
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shiphteey
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Posts: 2529
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posted January 31, 2009 05:19 AM
quote:
Ali, the PC3 controls the fuel by adjusting the duty cycle. It knows what is happening.
Your numbers are similar to what I saw and it convinced me to switch to a wet kit.
Keep in mind that the ecu will increase the duty cycle even more with ram air effects.
Have you installed a gauge to verify fuel pressure? The muzzy pump is supposed to be 50psi right?
Did RC blueprint the injectors? what were the flow numbers?
I hear you but I'm not sure how much I can trust the numbers the PC3 actually shows on my laptop. I'd like to see what the LM1 sees simulataneously for comparision. I'll probably try nat aspirated first for comparision and then spray and see what happens.
I'll be installing a fuel gauge inline and recording fuel pressure as well during the run. RC blueprinted the injectors, 3 were good going in, one was a little low. They call came back near peak, I'd have to dig up the paperwork but they were within one or so of each other and I was happy with that.
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Gemini Motorcycles
Topping out everything from Ninja 250s to nitrous ZX-14s.
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shiphteey
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posted January 31, 2009 05:22 AM
KZScott, others have been also keen on mentioning the regulator as the likely culprit. However I want to make one change at a time after I log and see what is going on. I'm not opposed to crushing the regulator like others say but I won't be able to undo that so I'd rather see what the bike is "actually" doing by comparing the LM1 to the PC3R at WOT up top on and off spray. From reading DM's Fuel Pump thread I guess I figured that the Muzzys Pump alone would essentially "cure" the wimpy fuel delivery issue of the stock 00. Should it not, I'd like to have some numbers to post so others can know too. If it helps one person from going too lean and blowing up it will have been worth it.
A.
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Gemini Motorcycles
Topping out everything from Ninja 250s to nitrous ZX-14s.
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Y2KZX12R
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posted January 31, 2009 05:43 AM
Ship, if the rail pressure never drops below 41psi then the regulator and pump are not an issue.
To cut the duty cycle you need bigger injectors. I have a set of purple Bosch injectors from Marren Fuel Injection that are 24% larger in volume. If your duty cycle is over 90% when on the spray I highly recomend them. They are custom made for the zx12r and fit without any shims etc.
injector.com
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2000redrocket
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posted January 31, 2009 11:23 AM
if you upp the pressure the resulting remapping with smaller # will drop the duty cycle. i would get one that is adjustable.
i do not know if this is the best way but others do it and it seems to work. you will have to lean out the map though. that may be a accross the board % for the whole map. if so that would be easy. but larger injectors would be the ticket though you loose controle on the low rpms delivery i am told. i am sure that is why bikes now have two injectors. the bigger ones do not work out as well for small amounts.
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KZScott
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posted January 31, 2009 01:37 PM
i just remembered this. you can use pressurised air to bump fuel pressure when you activate the nitrous. no remapping required, no nitrous map required. run the na map, and when the nitrous is activated a switching valve opens (like on an air shifter) and pressurizes the spring on the regulator (think turbo with more than one stage) use an air regulator to adjust the air pressure from your air shifter bottle. use that to get the correct AFR. more pressure more fuel, no increase in duty cycle, no map switching. if you dont believe me talk to Kevin Cadby 
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01 ZX-12R 8.84 @ 156.3 no bars, DOT tires. Pump Gas, NA.... turbo 8.47 @ 164.
00 ZX-12R 8.62 @ 165.2 no bars, slicks, Pump Gas, 55 shot.... turbo 8.32 @173
00 ZX-12R Fastest NA Kawasaki in the world 1: 222.046 1.5: 226.390 Loring AFB
00 ZX-12R street turbo 1: 227.9 1.5: 234.1 Loring AFB
00 ZX-12R LSR turbo 1: 263.1 1.5: 266.5 Loring AFB Worlds fastest ZX-12R
CMG Racing RCC Turbos
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2000redrocket
Pro
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posted January 31, 2009 02:00 PM
though i can not visualize the hardware you are talking about it sounds like a nice way to cut down on duty cycle with higher fuel pressure but only while on the button.
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KZScott
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posted January 31, 2009 03:07 PM
look at a turbo setup that has more than one stage of boost. you use air pressure to add pressure to the waste gate spring to increase boost. same thing here only its increasing the fuel pressure
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01 ZX-12R 8.84 @ 156.3 no bars, DOT tires. Pump Gas, NA.... turbo 8.47 @ 164.
00 ZX-12R 8.62 @ 165.2 no bars, slicks, Pump Gas, 55 shot.... turbo 8.32 @173
00 ZX-12R Fastest NA Kawasaki in the world 1: 222.046 1.5: 226.390 Loring AFB
00 ZX-12R street turbo 1: 227.9 1.5: 234.1 Loring AFB
00 ZX-12R LSR turbo 1: 263.1 1.5: 266.5 Loring AFB Worlds fastest ZX-12R
CMG Racing RCC Turbos
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ZX12-5807
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posted February 24, 2009 06:00 PM
Y2KZX12R
What cc size are those bosch injectors you have? And do you have a part number on them? I talked with Marren Inection today and he said the only ones he has that would work are 330cc or 430cc.
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2001 ZX12 1287cc
2001 ZX12 1317cc Lee's head
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shiphteey
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posted March 04, 2009 06:33 PM
Edited By: shiphteey on 5 Mar 2009 02:37
Just an update (sorry...been busy at the shop and trying to get caught up with bills....ok and street racing on a 9R and 1000 ;-) )
Anyways, so I picked up some fresh 93 pump gas yesterday and had one of the techs in the shop help me install a fuel pressure gauge inline. To see what is going on with the PSI. Before you know where you're going you need to know where you're at.
Thus far I have cleaned up stock A1 injectors, Muzzys fuel pump and the old PC3R as fuel related mods/upgrades. Playing with nitrous jets bigger than my tried and true high 30s/low 40s dry shot as stated I saw duty cycles quite high.
With the Fuel Presure gauge inline I noted what was going on with the gauge while my buddy cranked up the 12. Letting the pump prime, the gauge showed 30-40 psi roughly (I wasn't as intent on knowing the exact amount at that point). We started the bike and whether it was loping at idle (good ol' Muzzys cammy sound wap wap WAAP wap wap...) or giving it a little bit of throttle...say to 5 or 6,000 rpms the psi was at 60 psi.
A/F Ratio according to the LM1 at idle was about 14.7 or so give or take, as I opened up the throttle it got richer. Let the bike fully warm up, same thing, 60 psi.
Next step tomorrow is to check what the duty cycle (via the PC3) is naturally aspirated with this map. I'd like to hook duty cycle into the LM1...actually technically its the LMA3...I think its the 4th port and the 18th port on the ECU for 1st injector and negative.
In theory, since I'm spraying dry, duty cycle should still be ridiculously high even off nitrous, but A/F should be PIG RICH. If duty cycle is still quite high (which I believe it will be) as well as fuel pressure remain at 60 psi I will then start messing with the regulator. Sometimes the ZX12 pisses me off, and this fuel pressure regulator issue is no exception...can't find a picture of it online on the microfiche but I remembered I had pics of a spare set I sold not long ago and believe its the gold/brown colored housing that is in between the 3rd and 4th injector on the lower right hand side of this picture, just above the black plug:
In this picture, it would be between the 1st and 2nd throttle body openings going from left to right:
Anyone have any tips on crushing the regulator down? Can this be done while the throttle bodies are intact and actually SEE the fuel pressure go up? Or is it a PITA procedure where you have to disassemble, crimp down, hook everything back up, measure, rinse, repeat?
Thanks in advance.
A.
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entropy
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posted March 04, 2009 10:54 PM
Edited By: entropy on 5 Mar 2009 07:06
ship.
you are getting 60psi on the fuel line which runs from the pump to the rail????
hmmmmm.... on my heap i get 41-ish.
Are you seeing yr pressure gauge needle flutter when revs get high or is it steady?
I get flutter and don't know if it should be doing that.
I log duty cycle and the DL-32 shows pretty much exactly what the PC3r display shows.
Are you taking the signal for logging duty cycle "downstream" of the PC3??
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shiphteey
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posted March 05, 2009 07:09 AM
Edited By: shiphteey on 5 Mar 2009 15:10
Could possibly the the gauge. The gauge is routed in line right after it comes out of the pump (before it gets to the fuel rail), not on the return line. Karl, I get very minor flutter when I rev but for the most part it is almost dead set at 60. Grabbed some vice grips and briefly crimped the return hose and it showed 80 something...maybe about 85? Was under 90 for sure.
I'll be looking at obtaining another gauge...it could be the gauge is reading too high....
Test and Tune.....grrrrrrrrrrrrrrrrrrrrrrr
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Topping out everything from Ninja 250s to nitrous ZX-14s.
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KZScott
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posted March 05, 2009 11:54 AM
if you find out how to log duty cycle with the lm1 and lma3 (what i have too) let me know plz!!!
check out this thread on the old psycho board. i think the author is a "buddy" of yours lol
click
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01 ZX-12R 8.84 @ 156.3 no bars, DOT tires. Pump Gas, NA.... turbo 8.47 @ 164.
00 ZX-12R 8.62 @ 165.2 no bars, slicks, Pump Gas, 55 shot.... turbo 8.32 @173
00 ZX-12R Fastest NA Kawasaki in the world 1: 222.046 1.5: 226.390 Loring AFB
00 ZX-12R street turbo 1: 227.9 1.5: 234.1 Loring AFB
00 ZX-12R LSR turbo 1: 263.1 1.5: 266.5 Loring AFB Worlds fastest ZX-12R
CMG Racing RCC Turbos
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shiphteey
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Posts: 2529
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posted March 05, 2009 04:16 PM
Just picked up a new gauge, will test this weekend and see where fuel psi is.
KZ, terminal #4 on your 00/01 ECU is Injector #1 output signal. Terminal #18 is Injector Power Source Circuit Ground to Battery, that should be what you need...I'll give it a shot in the next couple of days and let you know.
A.
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Gemini Motorcycles
Topping out everything from Ninja 250s to nitrous ZX-14s.
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KZScott
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posted March 05, 2009 08:27 PM
cool, i appreciate it, i was told we couldnt log DC with the lm1/lma3 combo
____________
01 ZX-12R 8.84 @ 156.3 no bars, DOT tires. Pump Gas, NA.... turbo 8.47 @ 164.
00 ZX-12R 8.62 @ 165.2 no bars, slicks, Pump Gas, 55 shot.... turbo 8.32 @173
00 ZX-12R Fastest NA Kawasaki in the world 1: 222.046 1.5: 226.390 Loring AFB
00 ZX-12R street turbo 1: 227.9 1.5: 234.1 Loring AFB
00 ZX-12R LSR turbo 1: 263.1 1.5: 266.5 Loring AFB Worlds fastest ZX-12R
CMG Racing RCC Turbos
|
entropy
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posted March 06, 2009 12:07 AM
quote:
Just picked up a new gauge, will test this weekend and see where fuel psi is.
KZ, terminal #4 on your 00/01 ECU is Injector #1 output signal. Terminal #18 is Injector Power Source Circuit Ground to Battery, that should be what you need...I'll give it a shot in the next couple of days and let you know.
A.
Ali, are you using those two points to get duty cycle?
If so you are seeing the duty cycle generated by the ECU which is modified by the PC3 when you change the fuel map.
to get the dc signal seen by the injectors, you need to tap into an inj wire between the PC3 and the injector.
at least that was my experience 
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keith
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posted March 06, 2009 08:59 AM
Y2KZX12R - can you give me any more info on the Bosch purple injectors to see if I can source some here in the UK? I have a Y2K bike and have upped the fuel pressure to 60 psi but 60-70 shot is about the limit on the stock mikuni injectors which i beleive are 330cc per minute at 41 psi. Also with the Bosch ones is there any wiring alterations needed. Thanks, Keith
PS - at 60 psi the stock items pass in the region of 15% more than at 43 psi according to the test rig.
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mrsantafe
Zone Head
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posted March 15, 2009 09:54 AM
part number on those injectors please.........
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9.78@155.13 mph 1.71 60 ft @ a near mile high dragstrip
2006 ZX14 gone
2006 ZX10r (Wifes street bike)
2004 zx10r (her race bike)
2002 ZX12 (still kicking a--)
2007 gsxr 1k (race bike)
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shiphteey
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posted March 15, 2009 06:13 PM
Karl, I will hopefully have duty cycle logged on the LMA3 and RPM along with A/F. Going on the dyno tomorrow, will see what duty cycle is according to the PC3R and Innovate.
New gauge also shows 58ish psi idling and revving up in netural, minimal flutter as you mentioned earlier. Crimping the return line had the psi jump to about high 70s or low/mid 80s idling and revving fwiw.
Wish I had more damn money so I could just go wet or buy an aftermarket pressure regulator.
A.
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dougmeyer
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posted March 15, 2009 06:21 PM
Ali,
The duty cycle is what you tell it to be via the PC. What the higher volume pump gives you is the abi
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It's not that I think you're dumb, it's just that so much of what you know isn't true....
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shiphteey
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posted March 15, 2009 06:25 PM
Right, I guess I should be more clear. I meant that at a specific target a/f ratio spraying dry I'm not able to get the duty cycle of the injectors in the 80ish range...they are now in the 90s to 100% range, not good. This is with cleaned stock injectors and the muzzys fuel pump.
My goal is to be in the 80s for duty cycle based on my target a/f ratio....I think what will end up happening tomorrow on the dyno if all goes well will pretty much confirm that I am tapped out and will have to crunch the stock regulator down to bump up the psi enough to lower duty cycle given a specific target a/f I'm going for.
A.
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Gemini Motorcycles
Topping out everything from Ninja 250s to nitrous ZX-14s.
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