3.0l 16V Turbo Project
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Originally posted by Tomas L
You could connect a constant resistor to the DME NTC input, then the DME would not do any volume to mass conversion and you could use the mass flow signal. The downside of this is that the DME probably also uses the air temp for cold start enrichment.
You could connect a constant resistor to the DME NTC input, then the DME would not do any volume to mass conversion and you could use the mass flow signal. The downside of this is that the DME probably also uses the air temp for cold start enrichment.
The problem with reverse flow could perhaps be reduced by carfull design of the BOV outlet into the MAF pipe?
It seems not to be a flow problem. It is caused by different pressures.
To compensate for the faster response of the HFM5 I have thought of a rpm adjusted low pass filter.
#17
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Tom,
So your CPU handles the mass air to volume conversion that is typically accomplished by piggyback controllers more commonly used on the 951?
What kind of hp/tq will 1000 kg/hr support?
With the reliefs you've machined into the piston dish area, are you retaining the stock rod length? If so, what compression ratio do you think you're running?
Vic
So your CPU handles the mass air to volume conversion that is typically accomplished by piggyback controllers more commonly used on the 951?
What kind of hp/tq will 1000 kg/hr support?
With the reliefs you've machined into the piston dish area, are you retaining the stock rod length? If so, what compression ratio do you think you're running?
Vic
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Originally posted by Pauerman
So your CPU handles the mass air to volume conversion that is typically accomplished by piggyback controllers more commonly used on the 951?
So your CPU handles the mass air to volume conversion that is typically accomplished by piggyback controllers more commonly used on the 951?
The other point is that we want to be able to control the whole software - not only the mapping.
What kind of hp/tq will 1000 kg/hr support?
With the reliefs you've machined into the piston dish area, are you retaining the stock rod length? If so, what compression ratio do you think you're running?
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Originally posted by Duke
Detailes about what's done to the pistons, rods and head would be much appreciated
Detailes about what's done to the pistons, rods and head would be much appreciated
For detailed questions on the modifications you may contact Turbo-Uli directly. But he's currently "a little busy" since he has to support several cars in the racing season:
And there are a few other 3l turbos waiting for completion.
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Originally posted by Jfrahm
Why not use an atmospheric BOV to avoid the backflow?
Why not use an atmospheric BOV to avoid the backflow?
#23
Why not use an atmospheric BOV to avoid the backflow?
If the BOV is confusing the MAF you should get a similar effect, is that the problem you have?
What kind of hp/tq will 1000 kg/hr support?
The point is the "overshooting" of the flap.
If I remember correctly the flap is designed to open "to much", to give an accelerator pump effect, during full throttle, mostly in low to mid rpm.
Tomas
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Originally posted by Tomas L
An open BOV should only be used in a MAP system. With AFM or MAF an open BOV will let out air thats been measured by the flowmeter. The DME will think that the airflow in to the engine is larger than it really is and will deliver to much fuel. The cool side of this Tis that you should get large flames out of the exhaust at each shift...:-)
If the BOV is confusing the MAF you should get a similar effect, is that the problem you have?
An open BOV should only be used in a MAP system. With AFM or MAF an open BOV will let out air thats been measured by the flowmeter. The DME will think that the airflow in to the engine is larger than it really is and will deliver to much fuel. The cool side of this Tis that you should get large flames out of the exhaust at each shift...:-)
If the BOV is confusing the MAF you should get a similar effect, is that the problem you have?
The BOV confuses the MAF in a similar way because the measured air also leaves the system. We could solve that problem with a sensor with backflow measurement capabilities.
If I remember correctly the flap is designed to open "to much", to give an accelerator pump effect, during full throttle, mostly in low to mid rpm.
#25
I've been thinking about using a MAP signal just to get an accelerator pump effect. The MAP sensor is faster than a MAF and it senses pressure in the intake which gives it even greater speed advantage. The MAP sensor though has other problems making it unsuitable for a turbo car. If one just uses the MAP sensor to sense changes in manifold pressure and uses these changes as a correction to the MAF signal, you should get the best of both worlds.
Tomas
Tomas
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Originally posted by Tomas L
Which microcontroller are you using?
One with both A/D and D/A built in from what I can see in the picture.
Which microcontroller are you using?
One with both A/D and D/A built in from what I can see in the picture.
The actual version is based an a AVR chip with 10-Bit input channels and a 150 kHz, 8-bit high-speed PWM output. That 8 pin chip fits into the MAF adapter cable....
And yes - MAP has some advantages for racecars or if you are using a modern engine management. With the old Bosch DME/KLR you'll need a lot of helper-stuff to get it work correctly.
If I would like to keep the old Motronic, I would go the MAF way. With a modern standalone system I would take the MAP option. Our approach is not a additional piggyback system but a AFM compatible MAF device.
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is anyone going to have a full how to write up on this conversion?
What other benifits are there besides more power when going to a MAF?
Are there any cars out there that use the HFMs and what might be the right size for a 2.5L 951?
Where do I get the moterola processer and do I need to do any programming? I sounds like it is a universal processor.
Sean
What other benifits are there besides more power when going to a MAF?
Are there any cars out there that use the HFMs and what might be the right size for a 2.5L 951?
Where do I get the moterola processer and do I need to do any programming? I sounds like it is a universal processor.
Sean
#29
Your motor looks fantastic. Great job!
What really caught my eye was the MAF conversion. When I was looking for MAFs for my car I was not convinced that some of the vendors out therehad the best products so I went about building my own.
Originally I envisioned a Ford MAF sensor with my electronics that converted its signal to what the 951 Motronic expected. I built this circuit using a PIC18 (www.microchip.com) processor. However I did not want to use the built-in A/D as I wanted a much higher resolution (because I sometimes lean on the side of accuracy overkill), so I used an MCP 3201 and built an opamp filter circuit in front of it for filtering noise from the A/D converter. The A/D converter then went into a PIC18 that outputted the signal value to a serial port using a MAX232 driver. I tested it with
the regular AFM and it worked beautifully. At half open it was showing 2.5V and at full open 4.5V.
I was then planning to go to a friend's local tuner shop that had one of http://www.superflow.com/flowbench/sf1020/index.htm. I was going to measure for the same airflow the corresponding voltages on the AFM and MAF and then change the aforementioned PIC18's program to a simple lookup that sent the AFM's voltage for the MAF's based on my test above.
The only catch here was to choose a MAF with a diameter that did not exceed the AFM's airflow by a large value. I was thinking about a 70mm MAF but before I got to choose it I was swamped at work and never got back to my MAF project. If you want more details let me know.
The best part of all this was that this project would have cost me MAF + $100 max. Also I found a manufacturer at www.ussensor.com that could make a NTC resistor with the same characteristics as the
one in the AFM. They even sent me two samples. They said that if I bought a hundred of those it would cost me less than $100.
What really caught my eye was the MAF conversion. When I was looking for MAFs for my car I was not convinced that some of the vendors out therehad the best products so I went about building my own.
Originally I envisioned a Ford MAF sensor with my electronics that converted its signal to what the 951 Motronic expected. I built this circuit using a PIC18 (www.microchip.com) processor. However I did not want to use the built-in A/D as I wanted a much higher resolution (because I sometimes lean on the side of accuracy overkill), so I used an MCP 3201 and built an opamp filter circuit in front of it for filtering noise from the A/D converter. The A/D converter then went into a PIC18 that outputted the signal value to a serial port using a MAX232 driver. I tested it with
the regular AFM and it worked beautifully. At half open it was showing 2.5V and at full open 4.5V.
I was then planning to go to a friend's local tuner shop that had one of http://www.superflow.com/flowbench/sf1020/index.htm. I was going to measure for the same airflow the corresponding voltages on the AFM and MAF and then change the aforementioned PIC18's program to a simple lookup that sent the AFM's voltage for the MAF's based on my test above.
The only catch here was to choose a MAF with a diameter that did not exceed the AFM's airflow by a large value. I was thinking about a 70mm MAF but before I got to choose it I was swamped at work and never got back to my MAF project. If you want more details let me know.
The best part of all this was that this project would have cost me MAF + $100 max. Also I found a manufacturer at www.ussensor.com that could make a NTC resistor with the same characteristics as the
one in the AFM. They even sent me two samples. They said that if I bought a hundred of those it would cost me less than $100.
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@cgmonster:
You took the same way for your approach. I don't concern to much about absolute accuracy - the AFM isn't very precise and the 25 year old DME computer isn't too. The standard A/D port works fine.
The HFM5 includes a compatible NTC.
The creation of a lookup-table is simple:
You took the same way for your approach. I don't concern to much about absolute accuracy - the AFM isn't very precise and the 25 year old DME computer isn't too. The standard A/D port works fine.
The HFM5 includes a compatible NTC.
The creation of a lookup-table is simple: