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Data Logging on MAF vs AFM data


Tony240ZT

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Just wanted to give you guys something to let you know that the project that I was talking about where I was going to get a MAF working on a stock 280ZX Turbo ECU/Harness is still in motion.

 

I did a little bit of data logging while driving my orange 240zt around with the blue line being output from the AFM and brown data from the Z31 MAF. The figures have been manipulated a little bit so that they are compareable. Here is a snippit from my drive around the block:

 

cargraph.gif

 

Notice that the MAF (brown) seems to have more steps, is not quite as jerky, and it has a greater range of sensitivity. These are just a couple great reasons why those old AFMs should be swapped out. The major reason for me to do this is because my AFM has to be pretty tight to get it to idle with the larger injectors, making it really restrictive on the high side.

 

My car with the AFM has been running on the rich side, so I expected the blue (AFM) to be higher. The output after offsetting, inverting, and multiplying come out to be very compareable, so I think that I could make a system that is fully anolog and not programable for cheap, like say under $30, still allowing for slight adjustment, maybe just enough to run larger injectors without a problem.

 

The digital system will have many more features, and I'll be working to get it done first, as I think my car will really liven up with a custom fuel map since I have that little L24 that makes hardly any power until that mad t3/t4 turbo spools. I'm having to run good sized injectors to have that top end and I'd like to have a good idle.

 

I do expect to have an anolog system for the 280Z, and 280ZX NA, if I can get my hands on a 280Z test car. For Z31 guys I will do what I can to help you out, and I think you guys will require a digital system.

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The car was running on the AFM while collecting numbers. I need to find a good relationship between the two to get a starting point for my fuel map. I had the MAF strapped on right infront of the AFM, wired up, but not talking with the Nissan ECU.

 

I'm waiting for a new head temperature sensor to come in from Courtesy, I think mine is off a bit. Then I'll run and collect data again, find the relationship, and program it as my base fuel map, then start tweaking as needed from there.

 

I've had the car idling with the MAF and it does idle noticeably smoother. I had to manually enter all of the possible load points for an idle to get it to work, and that's not much fun. So, I'm now working on a windows application that will simplify setting it up and tweaking.

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Will those fuel maps you're working on be any good to those on an L28, since you have an L24?

 

If you make this thing work... :D ...well, I'm getting in line right now to buy one.

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Yes, my engine is going to be different. The whole idea of the system is flexability, and customizing the map to your car. I will probably need some help from people with commen setups to get a good solid base fuel map for those engines. I have my 280ZX NA to get an anolog system working for those cars, my 280zx is stock. I could use someone to help me with an anolog system for a 280Z. And I could use someone with a pretty much stock L28ET (stock block, injectors, and t3 turbo), it would be great if that person could run their car with my system intercooled and non intercooled to have a comparison. A laptop is needed for data logging.

 

Cusp, what is your engine setup, and what kind of features would you be looking for? Do you think you would be mostly interested in the cheaper anolog system or the full featured digital system?

 

Here is a web page I've wipped up for it, please feel free to correct any errors. The 3D modeling was done by myself, so please ask before using any of my images.

 

AFM to MAF Conversion Page

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I would probably be more interested in the analog version, as I don't own a laptop. Unfortunately, I might not be much use as a tester, my engine setup is pretty similar to Scotty's.

 

L28 stock internals, slight overbore

P90 slightly ported

T3/4 (not sure if it's an E or B comp)

Stock downpipe

NPR IC

420cc injectors

 

My car is currently decommisioned, awaiting cash flow to finish swap. If there is anything I can do though, let me know. With a project like this, you'll have no shortage of willing test subjects.

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