Yeah, i've seen quite a few dyno plots that suggest that the straight 272s don't actually give up any low end power to 264s -- despite what back of the envelope calculations would suggest. davidbushur will talk about this at length if you ask him. Work also sells 269s which are sort of between.

d

 

Sorry about the misunderstanding of the cams but ....



I run 264/272 -2/-2, used to run -4/-1 but after the tubular mani plus FMIC that setting proved to be laggy. On 272 running -4/-1 will not be as laggy.

 

Sorry to bump an old thread.....

Did anyone every successfully log boost through AN02 ?

 

Umm yeah i think so.. i'm pretty sure MAX711 set it up. See his post above, he has a datalog of MAP. i dont see it in this thread now, but i thought i remember him saying he hooked it up.. look around for it.

 

Yeah I saw his post and was encouraged. Unfortunately he never posted any of his logs

I was hoping that you, freedom or donour had figured it out and could give me some easy directions

 

Buy a GM 3 Bar map sensor, hook up +5v to the ECU +5v wire, hookup ground, then hookup the output signal wire to AN2 Input on the xede.

 

Sounds simple enough and logical...
Has anyone actually done it yet?

Not that I am concerned whether it will work or not but curious as to whether it was worth while.

BTW -- thanks for the help

freedom also mentioned that the voltages from the Defi sender might be compatible. This would be great for me as I could use existing hardware rather than buying new.
I wonder if he got it working?

 

Yeah, MAX711 did get it working. This is pretty much all he said about it:

And this website has the only voltage-to-boost table i can find. there is a downloadable Excel doc on there. http://hhscott.com/93tmv/3-bar_map.htm


As for the Defi, i guess you can test the sender with a multimeter to see what its range is. Heck, if you hook it up to a bicycle pump or something, you could theoretically see the boost readout on the gauge, check the voltage, and make your own conversion calculation too.

 

Sorry to bring this back, but anyone know if the voltage-to-boost conversion in the above link is accurate?

If not, does anyone have the voltage-to-boost conversion for a GM 3 bar sensor?

 

I didn't use a conversion table. Just read the value going into your Xede when the engine is shut off (i.e. atmospheric conditions) and then mess with the value until you get 14.7. The rest will follow, no need for a conversion table.

If I remember right, my GM sensor was putting out about 1 volt at atmospheric which the Xede will read as 51 (255/5, Xede reads 0-5 volts as 0-255), so multiply that by 0.288 and you get 14.7. Thats your absolute boost pressure, if you want gauge pressure just subtract 14.7. This assumes that the pressure outside is 14.7 on the day you set it up, but it doesn't change that much anyway.

It's really important to have an accurate 5 volt supply for the sensor, not 4.8 volts or 5.2 volts, but 5.

Hope that helps.

 

Here is the mapping plotted as pressure as a function of output voltage, as well as the Xede's y-axis vs. pressure.

In other words I did consider using a GM 3-bar map sensor as an input to my converter module, thus permitting fully closed loop boost control with the Xede.