Alky V6 Fuel Supply System Upgrade

[Alky V6]

The engine is demanding more fuel and boost. It's time to give it.
I'll be installing a 4 or 5 bar map sensor and will be upgrading the fuel system.
Presently, I'm running a single 2345-A Weldon pump with a voltage booster that is capable of increasing the voltage that drives the pump up to 50%. The engine has reached the limit of what this pump can supply being driven at over 16 volts.

I had no idea when I first put this engine configuration together that I would eventually be planning to push the output to over 1,200 Bhp. Originally, I thought I'd be very happy if the engine got me into the low tens, dreaming, maybe the high nines. Many people fought me on the idea that this configuration would be anywhere near successful. Well,... I have to call it, now. It's been an amazing success, and man, what an amazing ride it's been.
Now, it's time to push it beyond amazing success with the same out of the box thinking that got it this far.

Initial plans are to run the e-injectors off of the electric fuel pump and the mechanical nozzles off of a mechanical pump. The mechanical nozzles will be phased in as they always have been. The electronic and mechanical systems will be separate and will be free to use their own unique fuel supply pressure curves.
A second electric fuel pump will feed a surge fuel tank in the engine bay or in front of the radiator support. The size will be either 1 gallon or 1.5 gallons. The surge tank will feed the mechanical pump. The mech pump will be mounted where the evac pump is presently mounted and will be cog belt driven. The evac pump will be driven by cable. I haven't decided which accessory will drive the evac pump via cable.
Or, I may be switching to an electric evac pump, which would be the easiest solution for that. After all, I'm only using the evac pump to supply crankcase ventilation.

 

[Alky V6]

The fuel map has been reworked for the new 4 bar map sensor. To make this work, I'm going to have the cut back the e injectors twice in the high map region. It looks like the range to do this is there with the ecm if I can figure out the right fuel delivery strategy for the mechanical injection system.

 

[Alky V6]

The new MAP sensor is in.
0v = 29in/HG
4.8v = 43.5 psi Wooo Hooo!

 

[Raymond Bunch]

Donnie, you going to the track on Saturday for some TT?:wink:

 

[Alky V6]

Donnie, you going to the track on Saturday for some TT?:wink:

Yes. I'll be dialing in the new map sensor.
I may be late to the track. The track asked if I could paricipate with the car in a morning news spot to help promote the track. Don't know what pit spot I'll end up with.
If you plan to get there early, save our spot!

 

[Raymond Bunch]

Sounds like a plan and I'll try to get there early. Hey also, by chance do you have a 3 bar MAP sensor for sell, or that I can try out tomorrow. I have been running the stock one,dunno how I'm running as fast as I am with it. See you in the AM.

Ray

 

[Alky V6]

Sounds like a plan and I'll try to get there early. Hey also, by chance do you have a 3 bar MAP sensor for sell, or that I can try out tomorrow. I have been running the stock one,dunno how I'm running as fast as I am with it. See you in the AM.

Ray

I'll bring the old 3 bar with me so you can try it.

 

[Raymond Bunch]

Thanks a bunch.

 

[Alky V6]

Well. The car is insisting on teaching me more about itself. Dialing in the new map sensor has proved to be a little more difficult than I first thought. Making interesting progress, though.
One point that eluded me all day that finally hit me on the head like a brick was that the new map sensor may require me to set up a new map reading trigger point for the timing strategy of the aux fueling activation point.
I'll need to do this by simultaneously pressurizing the MAP sensor and aux fueling pressure sensor switch to find the actual map reading where the pressure sensor is activating, then a little offset thrown in for any physical fueling delay. Very likely this reading will be different with the different map sensor that is working on a different voltage ramp up scale, and also dealing with normal built in tolerances.
I really should have realized this right off the bat instead of torturing the poor car. Good things is, she survived the ordeal. She just coughed back at me as if to say, "Need some fuel here, dummy."

 

[Alky V6]

I found the issue with the aux fueling. When I entered the new MAP sensor into the software, it skewed the MAP values in all the parameters in the calibration bin file that asked for a MAP value. I had to go through all the tables and correct all of the parameters that had a MAP value entered, including the GPOs. I now have one of the GPOs controlling the aux fueling activation point. I started using that on top of the MAP pressure switch to get better timing with the activation point. The value should have been 232 kPa and had been skewed by the MAP sensor change in the software to over 300 kPa. That meant that the electronic injectors were cutting back at 238 kPa with the hope of the aux fueling coming in, but no fuel because it was set to come on at over 300 kPa. This gave a massive leaning to the mixture. So lean that it couldn't possibly hurt anything in the motor. It basically lean pops once, and then shuts down as if a rev limiter came on and cut fuel. This is a nice feature with the aux fueling. If for whatever reason the aux fueling fails to energize, the engine can't be damaged.

 

[Alky V6]

Surge tank strategy

Time to start thinking about how to setup the new aux fueling supply system.
The electronic injection system is fine as it is. There is the option to go with larger electronic injectors, if that is found to be needed. Right now, I don't think that will be necessary.
A soon to be added mechanical pump will supply the aux system only. The electronic injectors will stay on the present electric pump system.
I don't think I'll really need two electric pumps as I was originally planning. I think the present electric pump can supply the electronic injectors and keep a front mounted 1 to 1.5 gallon surge tank topped off through an orificed feed line. A return line for the surge tank will return excess fuel back to the main fuel cell.
The mechanical pump will be fed by the surge tank and will recirculate all the fuel back to the tank until the aux fueling system is activated. When the aux fueling system is activated, the mechanical pump will begin to draw down the fuel level in the surge tank and the electric pump will attempt to refill it through the orificed feed line. Since the amount of time that the car will be on the aux fueling system is short, the reserve capacity of the surge tank should be plenty to prevent running it dry before the end of a run. After the run, the electric pump will fill the surge tank until it is again topped off and the excess will again recirculate back through the e injection system return line back to the main fuel cell in the back of the car.
This setup will simplify the fuel system from the firewall to the back of the car. Basically, it will just be the same system as it is now, except for teeing off to feed the surge tank and the teeing back into the return line.
Piece of cake, so far.

 

[Alky V6]

Constant flow mechanical injection nozzles

The present plan is to stick with the present size mechanical injection nozzles. The added volume of fuel I will need to take the boost level higher will come from stepping up the pressure in the aux fueling feed system to the mechanical nozzles.
Volume and pressure of the aux fueling system will be tied to the engine rpm. The mechanical pump will be belt driven. Speed ratio to crankshaft speed still to be worked out once a mechanical pump size has been picked out.
The mechanical injection system may need its own referenced regulator, similar to the one being used on the e injection system. Still thinking on this point.
The stepping of the aux fueling system feed pressure will be handled by a jetted electric bypass valve. When the aux system is first activated, the bypass valve will bypass a certain volume of fuel back to the surge tank. This will lower the feed pressure to the mechanical nozzles. When 300 kPa is reached, the bypass valve will be shut to raise supply pressure and volume to the mechanical nozzles.
I see a problem with running the referenced regulator with the bypass valve strategy. I need to do more thinking on that. It's time to do more studying of mechanical fuel injection systems.

All the above is subject to change. After I have a basic strategy worked out, I'll be enlisting the help of Kinsler Fuel Injection to help out with picking out pump size, drive ratio, and jet sizing.

 

[Alky V6]

In the upper boost ranges where the aux fueling is energized, the electronic injectors will still be used as they always have been to trim the fuel supply to a fine level so that the engine gets a perfect a/f ratio.

 

[Otto J]

is the plan for another electic pump or are you going belt driven?

 

[Alky V6]

is the plan for another electic pump or are you going belt driven?

The electric pump I'm presently using will feed the nitrous system and the electronic injection system.
A new belt driven mechanical pump will feed the mechanical injection nozzles.
Two separate systems.

 

[Alky V6]

I have a one gallon fuel cell already mounted in front of the radiator that I was using for intercooler coolant. The intercooler sprung a leak and I've drained the IC system. I'm presently running the car with a dry liquid intercooler.
I can adapt the fuel cell to be used for the aux fuel, and if I find I need to repair the intercooler and run water again, I can plumb the IC coolant to a new tank located somewhere in the rear of the car.
But then, thinking about it more, maybe I need to fabricate something that doesn't have a fill cap. The fill cap on the present fuel cell could present a fuel leak problem with the way I plan to use the cell.

 

[Alky V6]

I've decided the first step will be fabricating and mounting the surge tank. I'll then plumb it into the existing fuel system. Then will come the belt driven pump.

The material for the fuel cell will be stainless steel. With the alcohol fuel, the SS material will prevent any chance of corrosion.
The cell should be simple. There will be one fitting at the bottom of the cell to feed the mechanical pump. One line to feed fuel to the cell and one line at the top of the cell to return excess fuel to the main fuel cell in the rear of the car. There will be no need for a fill cap or vent.
The fill line will be -6 and the return line will be -4. The line feeding the mechanical pump will be determined by the fitting size on the pump inlet.

 

[Alky V6]

The mechanical pump return line will either need to go back to the tank, which will require another fitting for the surge tank, or T'ed into the pump feed line.

 

[Alky V6]

To begin picking a mechanical fuel pump, I need to calculate what size is needed. Mechanical pumps are rated by a lbs/hr delivery rate, so I need to calculate how much fuel in lbs/hr the mechanical pump will need to deliver besides what the electronic injectors are already delivering.

Mechanical fuel pumps are typically driven at half crankshaft speed.

Let's calculate the total fuel requirement of the engine, and then figure out how much of that is being provided by the electronic injectors.

Projected HP Level X Brake Specific Fuel Consumption = lbs/hr requirement.

I'm going to pick a HP level that I have to think would be the max for my present configuration. 1,300 BHP, and a BSFC that is on the rich side for a methanol fueled engine, 1.30.

1,300 x 1.3 = 1,690 lbs/hr.
1,690 / 6 cylinders = 282 lbs/hr per cyl.

The present 160 lbs/hr electronic injectors are providing;
160 x .85 Duty Cycle = 136 lbs/hr per cyl.

282 - 136 = 146 lbs/hr per cyl.
146 x 6 cylinders = 876 lbs/hr needed to be provided by the constant flow mechanical fuel injection system.

In the Kinsler catalog, a KW-300 pump provides 845 lbs/hr at 3500 rpm pump speed. A '-0' pump provides 1070 lbs/hr at 3500 rpm pump speed.
It looks like a '-0' size pump would more than cover my application.
Kinsler now offers a new 'Tough Pump' design. Not sure which size in that product line I would need. Time to call Kinsler.

 

[Alky V6]

876 lbs/hr / 6.7 lbs (weight of one gallon of methanol) = 130 gallons/hr
130 gals/hr / 60 minutes = 2.179 gallons per minute.