ALFAGTV6.COM

ar4me · Post by **ar4me** » Wed May 14, 2008 7:37 pm

Race-Technology users,

Any of you guys come up with equations for mapping stock Alfa senders to Race-Technology readings (e.g. Dash2)? I would like to save my $$$ and re-use the existing Alfa senders wherever possible.

So, anyone came up with equations for:
1. Oil pressure
2. Water temp
These two Alfa senders are single wire, while (I think) the Race-Technology are all at least two pin, some three.

I also need to figure out the mapping from my Autometer senders for
1. Engine oil temp
2. Transmission + diff oil temp
3. FuelSafe fuel level
I doubt anyone has equations for those, but if you do, please post.

Jes

ar4me · Post by **ar4me** » Thu May 15, 2008 8:03 am

Let me ask another way:

1. Does anyone know the impedance (ohm) of the Alfa oil pressure sender (for the gauge) at various pressures? I.e. a table of corresponding pressure and impedance values.

2. Does anyone know the impedance (ohm) of the Alfa water temp sender (for the gauge, not the EMS) at various temps? This one I can generate myself, I suppose, by pulling it an measuring the impedance at various water temps.

Thanks for any help,
Jes

Micke · Post by **Micke** » Thu May 15, 2008 12:35 pm

I don't know. Sorry about that.
Just wanted to say that if you find out let us know.
I just paid my Dash2 and should get it next week.

Mats · Post by **Mats** » Thu May 15, 2008 10:12 pm

Micke wrote:I don't know. Sorry about that.
Just wanted to say that if you find out let us know.
I just paid my Dash2 and should get it next week.

+1

(Minus the Dash2)

ar4me · Post by **ar4me** » Thu May 15, 2008 10:19 pm

Tonight I measured some Alfa temp sensors I had laying around. I tried:
1. The stock sender for the temp gauge
2. The sender for the LJet EMS
Oddly, I couldn't get good impedance readings with 1 - they were all over the place. I will dig out another one tomorrow and try again - perhaps the one I first found is broken. With 2 I got good readings, and if configured with 5 V and a 1 kOhm pull-up resistor you get a nice linear relationship between temp and voltage - see pic for details.

During setup of DL1/DASH2 you simply enter the (temp, voltage) measurement points and it figures out the curve-fitting.

I used my tire pyrometer for temp measurements, so it should be accurate. However, the temp sensors take a little time for the impedance to settle.

It would be nice to use 1 since it is already there (serving the old dash gauge) and available. The sensor 2 would have to be fitted in the port currently occupied by 1 (since the existing 2 is used by the EMS) - unfortunately 1 and 2 are not the same thread size or pitch.

Not sure how to (conveniently) measure the oil pressure gauge...

Jes

ar4me · Post by **ar4me** » Fri May 16, 2008 9:12 pm

I suspect the Milano/75 gauge sender (1 above) was defect. I dug out a 164 gauge sender, which looks identical to the Milano/75 gauge sender, and it seems to work fine. It fits in the Milano/75 temp gauge sender port, and hence is easy to use. Find below the measurements.

Jes

Mats · Post by **Mats** » Sat May 17, 2008 12:22 am

Good Job!

For pressure readings I have a "buffer volume" tank with a hose connector (or whatever you want M10x1 for instance or 1/8 NPT) and 1 car tire valve. you just use a tire inflator thingie (calibrated) and give it some pressure, then you can bleed off very controlled. With a buffer volume the pressure change is less drastic, mine is a 30cm piece of exhaust with the ends welded up.

Mezevenf · Post by **Mezevenf** » Sat May 17, 2008 4:11 am

Micke wrote:I don't know. Sorry about that.
Just wanted to say that if you find out let us know.
I just paid my Dash2 and should get it next week.

+1 for me too!

ar4me · Post by **ar4me** » Sat May 17, 2008 5:45 am

Good idea, Mats

I can even just use my brake/clutch pressure bleeder which has the tank, a pump, and a gauge - same idea

Though, the pressure bleeder only goes to 30 psi

Guess, I need a tank like yours.

My only concern with the stock Alfa pressure sender is that it is known to have short life span. I wonder if it would make sense to put in a high quality oil pressure sender (a pain to change on the V6 - limited access, particularly with my 164-like setup). The flaky Alfa oil pressure sender (for the gauge) is "ok" in the Alfa setup since it has a separate (reliable) oil pressure sender for the minimum oil pressure warning light (7 psi, I think). With the DASH2 you set a threshold on the reading from the gauge sender, and hence rely solely on that, and hence, want it to be accurate and reliable

Hmm...

Jes

kevin · Post by **kevin** » Sat May 17, 2008 10:07 pm

Jes, i have been through three ' flaky ' pressure units (Alfa type) and dont trust them at all. I have connected up a mechanical one i bought from Bosch which goes into the side of the head (left bank) which gives perfect readings BUT the bastard thing leaks which occured at yesterdays race. Took two races to leak though. Water temp guage is a load of crap on GTV's as its pendulam based so on the lond left hand bends it soares to 110 and evens back out hence I got another one in the car which is connected to the outlet of thermostat so I can see temp in and out.

kevin · Post by **kevin** » Sat May 17, 2008 10:10 pm

Jes, i have been through three ' flaky ' pressure units (Alfa type) and dont trust them at all. I have connected up a mechanical one i bought from Bosch which goes into the side of the head (left bank) which gives perfect readings BUT the bastard thing leaks (at head)which occured at yesterdays race. Took two races to leak though. Water temp guage is a load of crap on GTV's as its pendulam based so on the lond left hand bends it soares to 110 and evens back out hence I got another one in the car which is connected to the outlet of thermostat so I can see temp in and out. Lost faith in Alfa electronic oil guages.

Post by **Zamani** » Sun May 18, 2008 12:34 am

What is good? I'm about to get some autometer gauges for:

Voltage
Oil pressure
Oil temperature
Water temperature

ar4me · Post by **ar4me** » Sun May 18, 2008 5:35 am

Zamani,

Unless you are ditching the Alfa instruments I would just use the factory water temp and oil pressure. I don't see why you want to replace the factory water temp, and as mentioned above the factory oil pressure setup is backed up by the min oil pressure sender. I would just stick with that. For voltage and oil temp I think the autometer senders and gauges are fine. I have used autometer electrical gauges and senders for engine oil temp and transmission oil temp without issues on the race car.

As an example of quality differences (assuming that there is something to "you get what you pay for"), the stock Alfa oil pressure sender (for the gauge) is probably around $50, while the one from Race-Technology is $230. They list the complete spec sheet for the sender: http://www.race-technology.com/oil__fue ... 8_976.html I would like to see <0.1% stability in 1 year from the Alfa sender. Though, the AN3 port fitting is odd (for US standards), but you can put together fittings to make it work. I will use the Race-Technology pressure sender for fuel pressure. BTW, I was trying to cross reference the Alfa oil pressure sender to something where I can look up the spec, but I haven't been successful.

Jes

Post by **Zamani** » Sun May 18, 2008 8:49 am

Problem with the factory senders.

Water temp sometimes read 50% of real value and sometime real value, and oil pressure is sometimes up sometimes down. Cannot trust any of them.

ar4me · Post by **ar4me** » Sun May 18, 2008 12:05 pm

I agree that the Milano/75 Alfa oil pressure sender (for the gauge) is inaccurate/short-lived, but personally I have never experienced a problem with a Milano/75 Alfa water temp sender (that includes 15+ years, 6, 7 or so different Milano/75s I have owned over the years, and obviously tons of miles). I don't think a typical aftermarket sender is any better - certainly not a cheapish autometer. I would suggest to just replace that sender.
Jes

Stock Alfa senders and Race Technology