I want to try and learn a bit, build my own boost display

[paulr33]

Ok Now I get the full picture. So If I was looking at logging the other ones you mentioned I would need to hook into the diag port and descramble the data from there. That sounds challenging

[DAMQIK GTS-T]

Thats why I mentioned to try something like the nissan ecu rom editor or link software.

[paulr33]

The diag port is used for "consult" the nissan diag computer and can do full diag engine checks and all other wierd stuff. it wont report values, only reports failures or mismatches based off templates to allow the dealer to retune it. ill look up the nissan ecu rom editor / link software to see what I can find

[DAMQIK GTS-T]

Hey Check this out

http://www.ooparts-international.com/id8.htm

[DAMQIK GTS-T]

and this http://300zx-twinturbo.com/conzult/

[paulr33]

That is so nuts!!!! I am so going to buy that

[DAMQIK GTS-T]

I have been trying to find a free verson of the software but as yet had no luck.

As I recon I could make the lead myself.

[paulr33]

Wicked as. Im gonna speak to them to make sure it works for an rb25det and ask them if I can get a demo of the unit in my car. Their in Buleen so thats a piece of piss.

Wicked as!@!!

Thanks heaps for your help qikgts

[paulr33]

Well I've emailed them in regards to it working on the RB25DET instead of the VG30DE/TT and AT for the 300ZX. I will keep you posted on their response. I'll see if I can find the software too

[b2barker]

Let us know how you go with the serial port buisiness.

DAMQIK GTS-T, do you know where MAP connects to the ECU? Is it shown on here this schematic? (ignore the cuts

Just to clarify, the data acquisition link I posted is just a cheap analog to digital convertor (the cheapest 12bit I have seen). Data loggers for cars aren't new but they are generally expensive and stand alone (ie they record data, and you down to PC later) or else a feature of an after market ECU. This one is is cheap, but has some limitations (like 0-4V instead of 0-5V) and the need to have your laptop connected. I am getting one to give it run, and from the RB25 schematic, it won't hard to pick up TPS, AFM, Eng temp and O2 from existing sensors. As pointed these are usless without RPM and or Tacho. RPM and Tacho probably need frequency to voltage converter electronics which are quite cheap. I was going to buy a MAP but DAMQIK GTS-T might be onto something. You could also add sensors like charge air temp or whatever.

[DAMQIK GTS-T]

Originally posted by b2barker

DAMQIK GTS-T, do you know where MAP connects to the ECU? Is it shown on here this schematic? (ignore the cuts

Yeah I know where it connects to the ecu, "IT DOSEN'T"

It is only connected to the boost gauge in the dash, thats it.

It is not shown on that ecu diag you posted i will find the circuit wiring for it and post it up.

Originally posted by b2barker

Just to clarify, the data acquisition link I posted is just a cheap analog to digital convertor (the cheapest 12bit I have seen). Data loggers for cars aren't new but they are generally expensive and stand alone (ie they record data, and you down to PC later) or else a feature of an after market ECU. This one is is cheap, but has some limitations (like 0-4V instead of 0-5V) and the need to have your laptop connected. I am getting one to give it run, and from the RB25 schematic, it won't hard to pick up TPS, AFM, Eng temp and O2 from existing sensors. As pointed these are usless without RPM and or Tacho. RPM and Tacho probably need frequency to voltage converter electronics which are quite cheap.  

To me this seem to be a waste of money because as you stated most of the nissan sensors work between 0-5volts or 0-12volts to aquire the data in 0-4volt range you would be missing the most important part (when everything is at full load) just my 2 cents,

I will oneday however buy one of these devices but not for use in my car.

With the tacho frequency why wouldnt you just feed this straight into your laptop? I mean seem's a little silly to convert to voltage and then analog to digital. the accuracy goes out the window.

Btw there is a tacho voltage output somewhere behind the dash.

[DAMQIK GTS-T]

I have also found this site to be usefull

the rb25 wiring diag is also here 1.25mb download

http://homepages.ihug.co.nz/~logic/carpage...odoreindex.html

[b2barker]

Yep but stepping down to 0-4V is simply done with two resistors. The same place have another similar product (Labjack ) for just over $200, with similar IO, but 0-10V, USB connected and terminals fitted. The sample rate is slower though

As far as the Hz/V convertor, I have used many of these in industry (mining) for speeds of conveyors and the like. I am not so much after accuracy as repeatability.

Thanks for that link, all info is good info. *goes looking for tacho

voltage*

[R33NT]

PaulR33,

If you are going to use that device from oceancontrols you would still need some additional analog electronics to scale the voltage down from 5 to 4volts (depending on the output of your map sensor). The other thing to check about the oceancontrols device is the input impedance, if it isnt in the Meg Ohms you may have problems with them loading the outputs of the sensors on your car.

If i where doing this i would simply build a small 5V buck converter (LM2673 from nat semi or similar). Include an ADUC812 (from analog devices) microcontroller, it has multiple analog inputs (12bit i think, ADUC824 is 24bit) and serial ISP coms. Then on the inputs to the ADuC812 i would be using something like an LMC6464AIM (rail to rail single rail opamp) in a voltage follower configuration to give me a high input impedance. Depending on the frequency at which you log the parameters you may want to use external SPI interfaced FRAM or external parallel interfaced SRAM. I would get hold of a demo copy of the Keil compiler (limited to 4k).

The above is a massively over simplified explanation of the basic components that could be used, it doesnt address noise, filtering, decoupling, etc . It doesnt even go into the PCB (printed circuit board) you would need to design and build as micro alone is a 44pin PQFP which cant be wired onto a piece of veroboard. Also without programming and microcontroller experience you dont have much of a chance.

For the people that said you simply take a 20x2 character LCD (with hitachi driver chip) and download a program you must be on drugs. It isnt at all that easy because you get different LCDs with variants on polled or delayed parallel (4 bit and 8bit data bus) coms which all require variants on the main program.

Unless you have a mate that is an Electronic Engineer with micro controller experience i would be giving up. If you had a friend who was in their last year of uni doing their major project you may want to suggest they do a device that logs all the above information and electronically controls boost or something similar (i was working on this type of device using fuzzy logic to control the boost until work and girlfriend got in the way).

Interfacing to the point where the "Nissan Consult" connects (which you can see in action at you nissan dealer) would be a neat project but without an outline of the data being transmitted / protocol being used it would be like looking for a needle in a haystack.

I dont mean to sound rude in the above ramblings but i see it so often where people who DONT know, trivialise the hardest form of engineering (that'll get the mechanical engineers that frequent this forum fired up).

B2Barker stepping down a voltage with a resistive divider is simple and not done because your divider has to be able to supply a certain amount of current to the analog input. To get a high enough output current you have to use a resistive divider with low input impedance which will load down the output of you sensors and give your ecu incorrect values!!!!!!!!!!!! Again over trivialising a problem by someone that doesnt know what they are talking about.

The nissan conzult looks good though, the PDA is a neat and cheap way of getting an other wise expensive ($1K alone) touch screen LCD with colour interface.

[paulr33]

Hi R33NT,

Thanks for your valuable input, at this stage im gonna wait to hearback from 300tx.com.au to see if it will work on the rb25det MT and see how that goes, I dont think I will be buying though. Would be cool to have. I've learn a huge amount in the post so thats for all the feedback and advice guys. Im no electronics engineer and certainly not keen on changing my idle timing and fuel ratios to speed my car, I wouldnt have a clue when it came to that, But what I would like to do is understand fuel curves and boost vs RPM but not change it, just understand how it affects power at the wheels etc and use real life data to learn from it and maybe even improve my driving habbits vs fuel economy etc.

Once again thanks, will update once I get a response from 300zx.com.au or whatever the site is

Cheers

[DAMQIK GTS-T]

Originally posted by R33NT

PaulR33,

             

Interfacing to the point where the "Nissan Consult" connects (which you can see in action at you nissan dealer) would be a neat project but without an outline of the data being transmitted / protocol being used it would be like looking for a needle in a haystack.

There is a starting point for everything

http://www.techedge.com.au/vehicle/aldl8192/8192hw.htm

as this site shows for the common cars among us.

I dont think it would be to hard to make your own consult for pc as the technology is now over 12 years old. and its serial.

[paulr33]

I got a reply from Simon at 300ZXTT and they said they are happy to test the conzult it in my car. Dont know if thats a good thing or not