Webber 750 engine

[Friendly]

In reference to the above post, If anyone is considering the Weber as a possible power source, what length wiring harness from the ECU to the engine would you like to see available? If we get a harness tailored to our needs, we should get the length close to what we think is appropriate.

 

[Trackwelder]

I would like to see someone with a tractor set up with 100 to 200 hours either in an aircraft or on a test stand after the bugs are worked out, my rotax is supposed to have 175hrs but has been sitting so I will have to put in new seals at a minimum, I have an oversize belly radiator so I should be okay there, I would love to see the turbo done up as my plane can handle a 912 and the next one I build they are using lycoming O235s in, I would rather have more power than I need and throttle back than have to little power but since the original of my next design flew on 50hp before they decided to upgrade to a C-85 I could almost stay N/A. I just want to see real world applications in the air, and I believe Neils three gear redrive would give me the best setup, Although I have not seen his price, or the price on a belt drive either.

 

[NavyDoc]

Finally at GTMO

Finally at GTMO

In reference to the above post, If anyone is considering the Weber as a possible power source, what length wiring harness from the ECU to the engine would you like to see available? If we get a harness tailored to our needs, we should get the length close to what we think is appropriate.

Hi Every one. I'm finally ready to start working in my engine. It just arrived today to Guantanmo Bay. I visited the car hobby shop here and it seens very limited to the tools they have available. I see you have make gret progress with wirering. I previously had purchase a microsquirt, but I see that for my turbo engine it may not be what I need.

 

[WHY]

Hi Dennis

Go to the Microsquirt Web site and read up on the capabilities of the unit, it is supposed to cover anything from a single cylinder to a V-8 fuely. I think they built in a couple of features into the Microsquirt that were not in the Megasquirt unless you added some options, could be wrong but read up on it. Have not tried to program mine yet but I am normal aspirated, otherwise the same. Weather and time have kept me slower than usual.

Tony

 

[Friendly]

Hi Every one. I'm finally ready to start working in my engine. It just arrived today to Guantanmo Bay. I visited the car hobby shop here and it seens very limited to the tools they have available. I see you have make gret progress with wirering. I previously had purchase a microsquirt, but I see that for my turbo engine it may not be what I need.

Dennis,
I think you can use the Microsquirt on the Turbo, It will have to run in Wasted spark, with a single trigger, I think, I have not read enough on it. The software is very flexible as far as engines go. In fact the Microsquirt, not the Megasquit is what DIY recommeded to me for my Turbo. I just want to keep the engine running in the same configuration as the Bosch ECU had it. Part of fun in building it was to see if I could get it to wire up same as the Bosch.

I am glad to see you made it there ok and really look forward to hearing about your Weber progress.

 

[WHY]

Hi Mark

My Microsquirt uses the crank for timing and the cam for cylinder selection, what is needed for the turbo, I don't know, it may need a second MAP sensor for boost ??

Tony

 

[Friendly]

Tony,
I don't know where the Mico picks up the second trigger (the cam) maybe it is already wired for dual ignition inputs.
I changed out the standard Map sensor that was on my board to the "Map Daddy 4" which is two Map sensors, on one, chip board.
The single map sensor reads pressure before the engine starts and uses that pressure to calculate the air density for mixture. The dual takes a second reading and compares the two to make corrections. So it would be beneficial for altitude changes even if you don't run a turbo. That is the beauty of electronic injection over carburetors. (my 2 cents).

But if you or I fly a gyro in Florida one week, and CO. the next, the computer should adj the mixtures automatically even with the single map, because it samples the pressure before it starts.
Tubo will need 2nd Map sensor, Intake Air Temp sensor, and input/out put circuit to operate the tubor wastegate

I am very close to making my first part on the new Mill, I should be back on the Weber soon.
I am excited to see Navy Doc , posting again.

 

[WHY]

Hi Mark

I think that Navy Doc will want to use that "Map Daddy 4" as well. My normally aspirated has a Walbro system that has the Map and AIT combined into one unit that mounts on to the dual throttle body system so it would take a unit like you used for the Bosch system. Yes, the cam is the second sensor used in the ignition system on the 2 cyllinder engine, it just alternates firing back and forth, works only on 2 cylinder this way.

Tony

 

[WHY]

Hi Mark

Bolts on the way, with explanation.

Tony

 

[WHY]

CORRECTION to above post

"Hi Jeff"

Bolts on the way, with explanation.

Tony

 

[JEFF TIPTON]

Much appreciated.

 

[Trackwelder]

Tony, I am just guessing here but couldn't you take the MAP reading down stream from the turbo, that way it would always be reading tha actual pressure on the intake side?

 

[WHY]

HI Eric

I am pretty dense when it comes to this EFI stuff but am learning a little. I think one map is used for altitude sensing the other is for the intake pressure.

Tony

 

[Trackwelder]

Not trying to start an argument, but if you have the intake pressure, why would you need to know the altitude, a turbo would spin up to x amouint of boost no matter if it was below sea level or up to any altitude you could fly at.

 

[WHY]

As I said Eric, I'm pretty dense about this EFI Stuff, so someone else will have to explain the need for the two Maps, I only use one on my N/A engine.

Tony

 

[Trackwelder]

I am looking for an explanation myself, since it seems that there is no easy way around using the snowmobile computer.

 

[JEFF TIPTON]

It's finally here and I've got plenty of them ready to ship-- The 'MapDaddy' 4-bar Manifold Absolute Pressure (MAP) Sensor upgrade for the MegaSquirt, with one primary 4-bar MAP sensor for standard MAP Sensor duties, and a second for realtime barometric correction so that your fueling calculations will stay accurate in the event of an elevation change (mountain runs anyone?). The design was well thought through and is completely compatible with the MegaSquirt-1/2/3 with either the B&G standard or the Extra code variants, also fully supports all major PCB versions, PCB2.2, PCB3.0, and PCB3.57 units. Pretty much any hardware platform is good to go...

http://www.diyautotune.com/catalog/mapdaddy-bar-map-sensor-with-barometric-correction-p-117.html

 

[Friendly]

Tony,
You are not dense, by any means. You have dealt with Carburetors and point ignitions and the EFI is just new terminology.
I can't explain as well as Chuck or Doug, some give me so latitude . Eric, I do not take your post to be argumentative. You are just trying to get a better understanding, same as the rest of us.

A carb, uses the float level and atmospheric pressure to flow certain amounts of fuel through the holes (jets) into the venturi area where it is mix with the incoming air.

We make those adjustments on the ground where the Temps and pressures are relatively stable. If we fly that engine higher and higher then the ratio of the air to fuel changes although we did not change anything on the engine.
So we know that the density of the the air became less as we gain altitude, but the jets do not know this and they still flow the fuel in large amounts resulting in a rich condition.

The Manifold Absolute Pressure (MAP) takes a reading on the ground. This is now the "standard" for the computer to make adjustments in the ratio of fuel delivered to the incoming air. It is varied by the engine temp, Throttle Position, and intake air temp. We have to have a starting point that will allow the ECU to go rich or lean, to start and warm up the engine, then run.

As long as we remain on the ground this is good reference numbers, same as a carb. But when we go up in altitude, we know that the air density has changed. The dual MAP will allow the ECU to measure the air density on the outside and compare it to the air density in the manifold. AS the turbo begins to add more air (oxygen) back into the manifold, the ECU can make air density calculations instantly. Also when you kick back to idle at altitude the ECU can read the two barometric sensors and make comparisons. It is able to adjust the pulse width of the injectors to increase or decrease fuel. More importantly is ignition timing can be advanced for power and then retarded some as the boost kicks in.

I hope this makes some sense.

 

[WHY]

Hey Mark

Thanks for kicking in that explanation on the MAP's. How goes it on your project, just got my oil tank (a brand new Briggs & Stratton lawnmower gast tank) and more oil line conncetions and fitting, got to go to the hangar in about a hour to play with the new parts (toys).

Tony

 

[Friendly]

Tony,
To be honest, I have not done anything on the Weber since I finished the Megasquirt. I purchased a CNC machine and I had to put in a bigger Electric Panel in the shop to handle it.
I read the manual through (twice). Writing a program was a bit more challenging than I thought it would be. I am trying it out on some small parts before I tackle the bell housing for the Weber.

It is nice to have it cut 4 parts that all look alike. These are the frames for a Butterfly Rotor Brake, one has the pockets cut for the starter bosses, the other three do not. I just add to the program until I get it where I want it. So I will try to finish these up for the people who ask me to build them.

This weekend is the Texas flyin at the Gatorfest. But the weather has really been great for working outdoors.