I'm planning on making some gauges(yes, digital, from scratch), but want to know what the appropriate ranges should be for fuel press (I have an idea) oil press(again, an idea), oil temp, water temp for a boosted or stock d16z6?

What are nominal temperatures (idling, cruising, etc.)?

 

Fuel press: 0-60 (unless you're running FMU, then maybe 110).
Oil pressure 0-100
oil temp...not sure on this one, maybe 100-300
water temp 100-255

How're you planning on making guages? I'm curious about your method.

Ryan P.

 

im curious as well, i have a engineer monkey in my basement that i could convince into making me as well

 

i want an engineer monkey!

 

Sorry, I've been MIA with work and sicknes...blah...

Anyway, as of right now I am going to make them with a 10 LED bargraph and an additional BRIGHT LED as a warning light, if the gauge seems to warrant it.

I'll have to give it some more thought before I settle on something definite, but I'll get back to ya then.

Thanks for the numbers, but does anyone have values for idle/cruising? Just to make that middle of the scale?

 

I would like to know how u are gonna do that w/out spending a good grand, cuz thermistors and LED outputs are expensive as ****, and thats the bottom line for temp... pressure is prolly a bigger bitch

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by stierhund &raquo;</TD></TR><TR><TD CLASS="quote">I would like to know how u are gonna do that w/out spending a good grand, cuz thermistors and LED outputs are expensive as ****, and thats the bottom line for temp... pressure is prolly a bigger bitch</TD></TR></TABLE>

Umm, no...you just buy senders from whatever company you like(autometer, VDO...). Without much looking, I can get two temp and two pressure in the appropriate range for $100. Chips are FREE (Up to 5 free samples from http://www.national.com and 2 from http://www.analogdevices.com) and LED bargraphs are $2.99 at Radioshack.
Thank you very much. And what the hell would I do with a thermistor? Do you mean a thermocouple? Only K-type (for EGT) are really expensive, and those are only about $50 if you don't let Greddy ream you in the *** for one.

The main reasons I am going to do this are:
Sometimes I will want to look at this ****, but not all the time (people with 10 autometer gauges are kidding themselves, since you can't pay attention to more than 2-3 and DRIVE at the same time).
I want warning lights/buzzers which only come on very expensive gauges (I believe) and I am poor.
I don't want to take up my whole freaking car with gauges.

My plan is to have about 8-10square inches taken up by these four gauges that will have warning lights (some if not all) and possible "audible alarms" for less than $150. I don't think you can beat that with a stick and even if you could, it wouldn't be as fun as soldering all this **** together.

 

Im planning on doing the same thing u are but w/one display... and are u sure that those senders are gonna be compatible w/the 2.99 led display u are talkin about even if u use data converters?
Thermistors.. thermocouples, are the same thing just diff words, and im not talkin about the EGT ones.
Im not bashin u, its just that I did my research for what I want too, and its a pain in the *** to get accurate readings.
We have the same goals, and I didnt mean to come off as mean as I did when I reread my post. Can u point out exactly what u plan to use for 1 temp, and 1 pressure?

 

do these senders come with datasheets? because if not, how will you calibrate it?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by keebler65 &raquo;</TD></TR><TR><TD CLASS="quote">do these senders come with datasheets? because if not, how will you calibrate it?</TD></TR></TABLE>

Well, boiling water is 212F, so that's the temp...I guess I could also go stand outside a bank and see what the signe reads

For the pressure, I'm not really sure...I may just hook them up to a air compressor and go from that reading, possibly adjust it for what it SHOULD be for my car, which isn't the best plan, but just assume it's running well now.

I think the point of this is NOT to say "wow, my coolant is exactly 272degrees F." But rather, "wow, my coolant is hotter than usual." So, the actual values don't REALLY matter, just the general range of things.

Stierhund, it's cool man, though it did seem like you were talkin smack
I'm under the impression that a thermistor changes resistance with temperature, while a thermocouple actually generates a (very small) voltage on it's own, because of the different expansion rates of disimilar metals in the probe. Correct me if I'm wrong.

In any case, I BELIEVE that the senders from VDO (inexpensive, but hopefully not CHEAP) generate a voltage and then I will have to scale that down (as it's probably +5v or +12v max) to 1v (kinda sketchy that the range is so small) and feed it into the LM3914 (believe that's the one) chip that divides 1v into 0.1v increments at different pins.

 

All that was over my head, but props for putting it all togeathor. Be sure to post pics when you get it done.

Blaze

 

I see what u are saying about the readings now, just getting a general idea of how it rises and falls. However w/enough information on the senders that you get you can get it right down to perfect accuracty I think... either way its gonna take a large amount of advil and time

Oh and I think u are right about the thermistors now that I think about it, cuz boilers use thermocouples and they go bad after a few years. But its kinda the same principle cuz boiler thermocouples are charged when the pilot is ignited.

 

Thermistors change their resistance based on temp. You can have either positive or negative temp coeffecients (sp?), which effect the 'direction' of resistance change with temp. Thermocouples do generate a small voltage at the junction of the two disimilar metals.

Using the LM3914, you do NOT have to limit their input voltage to 1v, quite the contrary, you make the top end of the scale whatever you want (within limits). You can also make the chip respond to a range other than 0-?v, as in you can specify that the lower limit be 1v and upper limit be 2v...you do not always have to use ground as the lower limit.

EDIT: Forgot to add that you can daisy chain these chips together to gain more resolution...I think the upper limit is about 10.

 

Ah, thanks EE_Chris, that makes sense. I remember seeing a display for a wideband that used I think 5 of those chips (and 5-10 LED bars) to have a high resolution display, which makes sense, seeing as it's a 0-5v range.

I guess I assumed it was 1v because I made an o2 display out of that and didn't recall properly.

I am starting to have second thoughts about this, mostly for aestethic reasons, but will probably do something or another. This is what happens when you have alot of time and little money on your hands

 

let me know how this works... I can solder and have a good electrical knowledge, but I just dont have the patience to figure out the actual numbers... I do want gauges (I'm a gauge *****) but at the same time, I want to have LED's for warning lights for things such as oil pressure, fuel pressure, water temp, ETC... If we can get this going, then I can help with some of the calibrations and things like that. I have access to Snap On Scanners, Digital Fuel & Oil Pressure testing points, and anything else that you could possibly want to test/read on a car...

Just let me know what I can do to help...