EGT Gauge 'Exactness'

[88_pacifica]

I've checked around and nobody has a definitive recommendation. After reading all the previous threads and posts and what not, nobody has really asked this question. Are digital EGT gauge packages considerably more reliable/exact than a 'sweeping' needle traditional guage? Or are the digital ones just a generic approximation of the temps rounded to certain degree increments(i.e every 10*, 25*, etc)? I am forced to get one obviously even with my minor upgrades, but I am really considering the pro sport guage link that 1fastcsx289 posted up since it appears to be a total package...

www.prosportgauges.com

It is fairly cheap, looks efficieint and since I'm not building a race car it should be good, right? However, the digitals are twice as much but I don't think they're really necessary unless it is way more reliable and a night-and-day difference with it's exactness and so on. I know that I plan on just keeping it "simple" for now, but experience tells me that 'later' I may want to keep "hopping" it up. Please let me know as I plan to buy this in the next day or two. Thanks guys.

[TurboGLH]

Gauge reaction time seems to be more a function of the thermocouple than the gauge. I talked with auto-meter at one point after seeing a fast reacting egt setup, and according to them the only difference between the regular and fast setup was the amount of shielding on the thermocouple. The problem appears to be that with the TC having less material, it's also more prone to breaking off and going for a ride down your exhaust, right into your turbine.

[MiniMopar]

Yeah, I did some experiments on my VDO EGT gauge. I took it apart and reverse-engineered the circuit. It's definitely the thermocouple that limits the reaction of the gauge. The chip that drives the indicator can really move if it wants to. They are also pretty accurate in converting the 2-6V input to a specific deflection angle of the needle.

The inaccuracies come from the correction and amplification of the thermocouple output. They have to compensate for the 2nd thermocouple at the back of the gauge. In this case, it doesn't matter if the gauge is digital or analog. If the signal conditioning is crap, the reading will be crappy. The VDO circuit was simple and took some shortcuts, but it seemed to be reasonably accurate compared to the digital gauge that I was using to measure the same flame. When you think about other factors, like positioning of the thermocouple, these errors don't mean as much.

[88_pacifica]

hmm.... well with all that being said I guess I need to see what will need to be my deciding factor. Pro Sport reliable? Maybe I should see if there are some threads out there on it.... Thanks guys.

[Aries_Turbo]

i have a westach egt package. like 80$ total when i bought it... maybe less. its been on the car for 20k+ miles. no issues. reacts fast enough for me.

[88_pacifica]

Aries.. where did you get it from and did it include everything? I got the exh mani that's on my car that was already tapped(prev owner) that came with the rebuilt long block and I don't know what size the threads, pitch, etc are. I assume they are all that same as an industry standard. It was tapped into the #4 bank, but I guess I should check to make sure that it has the right size. I REALLY don't want to dick with it any more than I have too since I threw the motor in the car before I put one in, whic I'm sure I'll regrett when i have to install the damm thing. Either way, I need it because I may be on the edge with fuel pressure/quantity until I check it against some actual guages. Thanks all...!

[1FastCSX289]

I had a problem with the first probe I got with the prosport EGT, but I think it was my location. The end of the probe, where the wires connected into it, was rubbing on my power steering pump. For some reason, the previous owner tapped the EGT into the no.1 primary on the header. I have since re-tapped a port on the #4 and its out of the way and havent had an issue since. Prosport did send me another probe, no questions asked. I dont even think I sent them my old one back. Guage seems plenty fast too.

[Aries_Turbo]

i got mine from relentless racing years ago. i know aircraft spruce has them.

Brian

[contraption22]

I had the cheapie autometer in my car at one time, and it always frightened me that the guage was still rising as the car went thru the traps. How much faster were the EGT's rising than the needle?(shrugs)

[Tony Hanna]

I'm running a Westach gauge as well.
http://www.airstuff.com/eshop/10Expand.asp?ProductCode=WS2C2
They used to have a really good deal on EGT/Thermocouple packages, but it looks like they only sell them seperately now.

[Aries_Turbo]

yeah thats about the price i paid for mine. its worked flawlessly. the probe is a little over 1/8" and it responds pretty quick I would say.

Brian

[Tony Hanna]

Mine has worked flawlessly as well, but I can't really give a valid opinion on response time because I have the thermocouple downstream of the turbine. If the headgasket would ever pop and give me a good reason to pull the head off, I'd move it to the manifold.:)

[Mysterio]

My gauge moves up and down relatively fast. It's an autometer cobalt. It was like $130 I think. I have it on the downpipe right after the swingvalve though.

[moparzrule]

I've found that all the EGT gauges that use a 12v power source are slower than the gauges that strictly run off the probe. I've used the Isspro and autometer sport comp, both were slow. I've love my westach and it requires way less to install. And yeah the probe is 3/16''.

[overlordsshadow]

I sure hope my maniold holds up with this 37/64's hole in the side of the #4 runner. The digi gauge I have reacts fairly fast and its accurate 1 degree C or 2 degree F accross its 1800 F range.