I've already got a A/F mixture gauge, and a CHT gauge to install. Would it be worth putting in an EGT gauge (I can get a good deal on one) too, or is that just overkill? Oh yeah, running a carbed 2.0L (or at least will be), 44 IDF's, WebCam, etc...

My initial thought is that it would be helpful in tuning, and maybe keeping my valve seats where they belong.

an ECT coupled with a CHT is almost as good as a dyno for engine tuning. run one, actually a pair!

What exactly can you tell from EGT gauge readings? Is there a temp range that is best for our cars? Oh, and where is a good place to get CHT and EGT gauges. I'm thinking they might be useful.

Westach and Aircraft Spruce both sell dual gauges with CHT and EGT in one 2" package.

Wicks Aircraft

Aircraft Spruce is good too - i just happened on the Wicks site while looking for rectangular steel tube ...

EGT is a very accurate way to see engine efficiency... It is efficient in telling you if you are rich lean or have the proper spark advance.

Its more of a tool for me than anything else. I live by mine on the dyno.

Cool. Sounds like I should pick one up. What temp range should a stock 2.0L be running in? And, where and how does the sensor mount? Does it just go in the end of the exhaust, or do you need to install a bung like an O2 sensor?

Whats the concencus here for EGT target temps?

We tune turbo 911's at about 1550 and a/f at about 13.5

NA engines about 1350

any thoughts?

The sensor is a tapered pin. You drill a small hole in the exhaust near(ish) the exhaust port, insert the probe, and it's held down with a supplied clamp. The taper provides the seal.

That has got to be begging for an exhaust leak eventually on a street car.

what if you ever want to remove it... the sender has to stay to keep the pipes plugged!

that's exactly how at least 90% of EGT-equipped piston aircraft work,,,
a very few may have permanent bungs fitted - but i doubt it.
aircraft do have annual inspections to check such things; i suspect any EGT-equipped car is checked at least that often.

why do you want one on a street car?

race cars use them because they're at a different track every event, the air density changes all over the map with the weather, and they must stay at the peak of performance (or they'll lose). most don't have active mixture controls -- or cockpit-adjustable mixture controls like aircraft do.

and yes - they're designed for permanent installation. if you want something temporary, you could use something like the header stub-pipe setup.

assuming you -do- decide you need one, why would you just as suddenly decide you 'don't- want one ?

drill the hole one size smaller than the probe and ream it for a tight fit. then install the clamp and no leaks.

2 of my stub pipes have a bung for some kind of sensor, looks too small for O2 so are they tapped for EGT?

Is there and EGT probe that has a pipe thread?

thanks,

You've convinced me...I must install one.

So Jake, since you seem to have the most experience with these EGT gauges, what's a safe/good temp to be running at? Will the temp be consistant throughout the RPM range?

1150

Exhaust temp is important enough to me that I bought a high quality digital aircraft EGT/CHT with 8 channels; I use 4 for egt and 2 for cht. I found the commonly available Westach dual egt to be of marginal quality for racing use.
At WOT I like to see 1250-1300F. The engine makes a little more power if the temp is up to 1350, but I don't like to run it any higher. Temps below 1200F usually are accompanied by significant power loss/bogging.

1150 is good for a street car operating at less than WOT...

Race engines need 12-1300.

OK so Im in the ballpark.....

I wonder where I can get some hard info about this... We tune750 hp turbo engines we tune them at higher EGT's 1550-1650.. but with a richer mixture...

We got most of this info from when we used to rent dyno time for tuning.. the "tuner" would just tell us temps and have nothing to back it up with.. I realize different engine will have different "optimum " combustion temps... one temp for most efficient least emissions, another for more power.

So an EGT wouldn't be real useful for a street car? What would be the most useful? CHT and oil temp? What about an air/fuel gauge? I'm getting a little paranoid about running hot/lean. Don't want to be dropping no valve seats!

I can tell you that 90% of the afm gauges you see out there are crap and won't tell you much except if you are grossly rich or lean... They won't even tell you by how much in most cases.

Ok, I'm thinking an oil temp gauge, and a CHT gauge with a sensor on each cylinder and a 4 position switch. I imagine that would be enough info on what the engine is doing? Anybody have any thoughts?

Sometimes just knowing which side you're on can be very helpful. A dyno and gas analyzer is best, a wideband O2 sensor is good, and a narrow band O2 sensor is better than nothing.

-Ben M.

westach has QUAD CHT gauges... very cool

I asked Ross at SDS why they only sold the narrow band O2 sensor (as does haltec), he said that they found too much info, in the wrong hands, was dangerous.
They've found that in most cases, with their system, the narrow band is good enough. He said if you must have it better then go to a good rolling dyno shop.

That's great for a water cooled engine that wants to run 14.8. For an aircooled engine that will run hot and drop seats unless you run it at 13.5, that's probably an issue... It's a roll of the dice with the NB sensor.

I've had my haltec NB since '96 and have built and tuned around a hundred T1 hipo (carbed) engines. Never once have I dropped a valve or lost an engine due to fuel ratio.
The very few that have gone south were all the cam/lifter problems.

I'm running a SDS FI on my teen now and it's working fine, but I don't have much time on it. We'll see if I have problems with it this spring/summer.
This engine is expendable so I don't care if it does go boom.

Those are the best kind.

Ok, so I have absolutely no experience with NB sensors, so I am talking out of my ass.

But I have read a lot of the literature and I am working on a WBO2 setup for my Megasquirt system. And the reason I chose WB was because when I looked at the voltage vs. mixture curve for the NB sensors I immediately understood what everyone was talking about - they have zero resolution outside of 14.8 AFM. But if you know that and use them as a guide only I guess you can work around it unless you need to set the mixture very accurately.

It's really interesting to me that you have gotten it to work reliably. Very cool. Do you always richen them up a little beyond what the NB sensor says is stoich?

I found my new EGT gauge!

where you going to mount that one eh?