hurry up with the work stuff Slash. I'm over itching for some updates

 

LOL, I can't wait to get back to it either!

 

I am curious about your impressions on changing out the ssv to open earlier or open all the time.

 

I did some reaserch, and have the parts for a variable voltage divider on order. Right now I am looking for a MAF extension cable so I don't have to cut my stock harness.

If anyone knows where to buy one let me know.

My minimum order was 10 pieces so If it works I have enough parts for 9 others.

 

Please let me know if you find the MAF extension cable or connector. Only place I could come up with one is OEM harness at a salvage yard.

 

Slash, how far away are you trying to mount your Maf? The Maf wiring is quite long, all you have to do is unravel it from the wiring loom and you will see that it goes all the way down to the main fuse box.
When I repositioned my Maf, I ended up with miles of spare wire, that I ended up folding in half and hiding under the main fuse box.

Rotaman

 

Sweet man . I would imagine it would be best to keep the resolution as fine as possible so I would suggest a max of 20% voltage reduction.

 

Denso MAF extension.

Underdog Racing Development

 

I might be missing something here, but it does not seem logical that there will be a major voltage drop by extending leads?

Ref http://en.wikipedia.org/wiki/Mass_flow_sensor I would presume a well designed harness have close to zero voltage drop, you want the heated wire inside sensor to dictate as much as possible of current/voltage changes, not temperature in engine bay etc., as would be the case with undersized conductors.

 

Yes you are - two different conversations .
One on a maf extender for reducing voltage and the other maf extender for lengthening the wires .

Easy to see how you got that confused

 

And if you want voltage over sensor to be really accurate, it's quite easy to compensate for conductor loss in regulator by adding a extra wire for feedback.

EDIT: Did not see your reply before posting this. Making a voltage regulator is usually quite easy DIY, but that might not be an option here. Do you want to change voltage to avoid ECU to saturate at this feedback? Do you have a schematic for this circuit? Then, for once, I might be able to contribute.

 

I think 20% would be plenty. 5 volts/0.8=6.25 Volts. So that's an aditional 1.25 Volts. Looking at the slope on the MAF calibration it would be a huge increase in flow.

4.69volts stock max-1.25 Volts=3.44 or about 135g/sec compared to 365g/sec at 4.69 volts. That's 230g/sec differance. I bet with the aditional slope we are looking at 700+ g/sec on stock MAF with 6.25 Volts.

Looking at the idle side of the map I idle around 1.33*.8 drops to 1.064 Which is a aweful close to those first two cells on the MAF scale. So Maybe a 15% decrease. 1.33*.85=1.13 puts it about 6 cells from the left. 5/.85=5.88 Volts Which I would say is 600+ g/sec.

Now When I get done changing the 16 Spark plugs on my wifes truck I'll check to see if the MAF is actually putting out more then 5 volts but the cobb/car is not registering it.

 

Looks like 15% max will be heaps .
But yeah , need to know if we can actually get more than 5v first.

 

Thanks 9K I saw that one, but wasen't sure if it was right or not.

 

Yeah, the parts I ordered totaled 1.85 USD so it's no big deal for some experimenting and learning

 

I don't need to extend, I was after the connectors so I could make a "Y" adapter and put a second MAF post turbo for IAT.

 

Awesome, thx!

 

5.63 Volts

I am going to swap it out at Auto zone to see if I get the same out of another sensor.

Any guesses on how much g/sec you get from 5.63 Volts?

 

(420/5 ) 5.63 = 472

Enough for 400whp +


Do we know that the ECU wont read more than 5V yet ?

 

That would be for a linear slope. Depending on the actual curve it could be capable of measuring much more at that voltage. Also, the curve is kinda wonky. It looks like a smooth curve in ATR but plotting the top end in finer resolution (or by looking at the values if you are good with numbers) reveals that the rate of rise drops off. At any rate, without flow testing against a known control value then I think (420/5 ) 5.63 = 472 works close enough and then we adjust with VE. If the MAF, in fact, reads higher than 5V

 

Agreed. I was thinking

.63volts


4.69volts=365 g/sec
4.69-.6volts3=4.06volts or 233g/sec
365g/sec-233g/sec=132differance
5.63-4.69=0.94volts/.63volts=1.49*132=196g/sec
196+365=561 and I think that's a little low.

 

Can i ask how you arrived at that ?

Also , do we know for sure that the ECU wont read that ?

 

When looking at the plug contacts on the wiring harness. there are 5 pins. Lets label them from left to right a,b,c,d,e

With the Key in the run position but the engine off.

A=11.66 Volts
B=Ground
C=MAF Signal
D=ground
E=5 Volts


D and E might be swaped I don't remember.



With the sensor pluged in I pushed volt meter probes into the back of the plug.

A to b=11.66 Volts
A to c=nothing
A to D=11.66 Volts
I did not put A to E becuse they are both positive.

B-c 0.7-0.8 Volts.(the same the cobb showed for MAF voltage)
b-d nothing
b-e 5 Volts

c-a= I did not do because they were both positive
c-b=0.7-0.8 Volts.(the same the cobb showed for MAF voltage)
c-d=0.7-0.8 Volts.(the same the cobb showed for MAF voltage)
c-e I did not do this since they are both positive.

D-E= 2.12 volts(IAT when I blew compressed air the voltage went up. When I blew my breth it went down.


I Plugged the probes into c and b then blew compressed air directly into the MAF. The Volt meter showed 5.63 volts. The cobb showed 5 Volts.

 

Good work - thanks .
When you blew air down it were you able to adjust the flow to get various voltages showing ?

 

Yes, up until I hit 5 volts the volt meter read right inline with the Cobb.

I don't remember the numbers.

With my breath it was about 2 volts.
Then I used the Air through a cheap blower fitting
20PSI and was in the 3 volt range
40PSI was 4.8 or so
60 PSI was 5.63
150PSI 5.63

When I did this I was holding the MAF sensor in one hand and the air hose in the other.