Belly Tank Build Diary

[Mike Brown]

G'day Mike,  have successfully ran 30* naturally aspirated (EFI) in my Kawasaki ZX12R (1200cc) @11500rpm, and set 4 FIM and one DLRA record in the process,, I profess to know little, and as you say, information regarding small doses is almost non existent,,

First suggestion, do not ask advice of any top fuel persons because all thay know (and want to talk about) is 95+*,,

The temperature of the mix is critical, as you would be aware temperature changes percentage,, (ambient, blower, 5mile)

You are attempting to burn/ignite two different fuels,, Below 30* Nitro dilutes the Methanol, above 30* the BTU's in Nitro take control over the Methanol, the heat energy released becomes much more pronounced with each percentage added,,

I ran your calculations against mine (long hand, not computer generated) and came up pretty close to yours,, I note that yours are based on 4.81a/f, .744 lambda, may I suggest go richer,,

Volume, you can never have enough volume, also that methanol/Nitro mix is heavy so slow down the injectors duty cycle to 40-60*(larger injectors), did I mention volume  ,,

Dose small percentages make a difference ?, you betcha it dose 

First off thank you for chiming in on this post.  I can send you the spreadsheet that I used if you would like, landracing.com does not allow spreadsheets to be attached.  I will plug in the 4.81 A/F ratio and see where that takes me.  I plan to go with as large of injectors as I can and still have a reasonable idle.  My pressure regulator is referenced to the intake manifold pressure so the pressure does come down at idle and goes up with boost.  My plan was to go with injectors at their 45 psi ratings understanding that by increasing the pressure I can affectively make them flow more.  If I switch to an aftermarket ECU I can add injectors up stream of the supercharger that would come on when needed.  I would like to see if low dose nitromethane is practical however with just a fuel pump and injector upgrade. 

[SPDRACR]

Mike, Have You thought about Nitrous ?, It works great with electronic fuel injection.
just another idea 
Eric

[Mike Brown]

Mike, Have You thought about Nitrous ?, It works great with electronic fuel injection.
just another idea 
Eric

I have considered nitrous.  WeaponX here in Cincinnati (I use their dyno) has a great system that installs between the top cover and the intake manifold with individual fuel and nitrous nozzles for each cylinder.  The advantage to me is that I struggle to hook up all the horsepower I have in the lower gears so I could chose to only spray in high gear at wide open throttle.  Definitely an advantage.  There are however disadvantages.  The first is that I am using a stock GM ECU and worry about being able to reduce timing only while spraying.  The other is that this is a belly tank style lakester.  There is so little room for a nitrous bottle and all the additional equipment needed to make this happen.  Regardless of which direction I head I will still need to upgrade to larger injectors and fuel pump.  If I can get the same horsepower with injectors and fuel pump upgrade by just switching fuel it seems like a good path and it is nitromethane!

[Mike Brown]

This is a potential injector that was recommended for my application.  Spud Miller of FuelInjectionEnt.com recommends 4% toluene by volume in low dose nitromethane applications to help stabilize the fuel and reduce the potential of detonation.  Does anyone have any experience with toluene as an additive? 

[Mike Brown]

I wanted to include manifold temperature (the air temperature after the supercharger's intercooler) but this condition is not included in the OBDII signals that are sent out of the factory ECM.  I was planning to disassemble the blower cover to drill and tap for a second sensor put the material is very thin and would most likely require welding a bung in place.  At the PRI show I was able to discuss this dilemma with the people from AEM that supplied the logger that I use.  I found out that the analog inputs have pull up resistors that can be turned on and off in the software.  By turning the pull up resistor off I can "piggyback" on the sensor that connects to the factory ECM without any ill affects.  After wiring this sensor to the logger the only complication was then to create a graph in the logger that represented the temperature in relation to the voltage that the logger is seeing.  On the internet I found the manufactures specifications of what resistance equaled the temperature in degrees C.  I then put this information into a spreadsheet that calculated the voltage based upon the voltage present at the sensor and the value of the pullup resistor.  The temperature was then converted to degrees F.  The AEM logger allows up to 30 points for calculations.  After some trial and error to get the best value for the pullup resistor the calibrations appear to be working correctly. 

[Mike Brown]

We went to the spring ECTA event.  On the first run at about 3/4 of a mile the power went down smoothly like gently lifting off of the throttle.  Looking over the data from the logger the engine went lean and the ECM shut the engine down.  I was expecting this to happen, just not this soon.  I have been running VP MS109 which contains MTBE as an oxygenator.  Every component in my fuel system except the injectors was compatible with this fuel.  With the injectors running at 90% duty cycle I knew they needed upgraded but I was putting it off until I decided on the next steps.  Inspection of the plugs revealed no damage, the ECM shut the engine down before anything bad happened.  I am thankful for that.  I have decided to add a wet nitrous system because once I go down the nitromethane route the fuel system would not accommodate any other fuel which limits what I can do with the car.  More to come on the nitrous as we hit the dyno with new Injector Dynamic 1,050cc injectors which are compatible with all fuel including nitromethane and MTBE. 

[Mike Brown]

I had an open analog channel on my data logger and decided to add exhaust gas temperature.  I had previously added a fourth O2 sensor bung for the tuners wide band sensor when running on the dyno.  I machined a fitting.  The male threads are M18x1.5 threads to fit into the O2 bung.  I then machined a brass ferrule for the thermocouple.  A bolt with 3/8-24 threads was machined to hold the thermocouple into the fitting somewhat like an inverted flare fitting for a brake line.  The thermocouple came from Amazon for less than $10 with a 2,000 degree F range and a 3 meter stainless steel lead. 

[Mike Brown]

Thermocouples cannot be coupled directly to the logger, the signals need to be amplified.  AEM sells an 8 channel thermocouple amplifier for $400+ and I only needed one channel at this point.  I was able to get from Ebay a single channel amplifier for $30.  This amplifier uses an AD8495 chip from Analog devices that I am familiar with and provides a linear 4mV/degree C output.  This amplifier has a 32-2282 F output range.  This amplifier also uses 8-32Vdc power so it works properly on the 12V system in the car.  It took some trial and error with testing to get this connected to my logger and verify its accuracy.  The logger is very compact and comes with a partial enclosure that has slots for mounting. 

[Mike Brown]

With very little room in a belly tank there was only one spot that I could mount a 5 pound nitrous bottle.  I fabricated mounts from 1" x 1/4" steel bar. 

[Mike Brown]

The bottle is mounted with only plumbing and wiring left to complete. 

[fissionspeed]

I'm eager to see where your Nitro + EFI journey takes you. I have been doing considerable reading on the topic (Bob Sbazo has some great books) but the documentation covers almost exclusively mechanical fuel injection and analog ignition. Supposedly a modern coil pack and spark plug will light off methanol just fine. I'm interested to see how the O2 sensors feel about it.

[bearingburner]

Do you plan to go to Loring ME this summer?

[Mike Brown]

Do you plan to go to Loring ME this summer?

Unfortunately Loring is not in our plans for this year. 

[Mike Brown]

I decided to put the nitrous activation switch on the butterfly style steering wheel.  The steering wheel never seemed to be any sturdier than it needed to be so I was reluctant to start drilling holes in it or welding brackets on.  I decided to machine a " clamp on" style mount.  I started with two pieces of aluminum that were pinned and held together with 8-32 socket cap screws.  I then machined and open slot that would fit on the spoke of the steering wheel.  Since the switch was offset in the mount I used a four jaw chuck in the lathe to hold the mount to drill, bore and thread the hole for the switch.  I felt that the threads were unusual at 5/8-24.  I would have expected 5/8-32 which is a more standard electrical equipment thread.  Single pointing threads on a CNC lathe makes this job easy as the thread pitch is just one of the numbers that you input. 

[Mike Brown]

A photo of the assembled mount.