EGT Gauge vs. Wideband

[oskinosmee]

Whats the difference? Which one shold i be buying if i want to up my boost?
How much boost can i up it to? Sorry for the newbie questions this is my first turbo car and Thank You

 

[Haltech]

I use both.. Widebands are great for tuning. Problem is, using that wideband sensor for everyday driving can cost you down the road when it gets toasted. Thats where the EGT comes into play. when you start seeing temps rise, you know youre leaning out.

 

[redspeed]

EGT tell you the exhaust temp. You need to know whats the normal exhaust temp in your car so you can use that as a base temp. So basically install it when your still stock. Higher temperature, lean, lower temperature, rich. Wideband o2 sensor will tell you the A/F(air/fuel) ratio more accurate than a regular o2 sensor. I read somewhere that the ms3 has a wideband from factory, somebody correct me if I'm wrong.

 

[Craighjr]

Haltech did you ever get that scantool software up and running? My modis can't tell me if the o2 sensor is a 0-1v narrow or 10-16v wideband. I still haven't installed a wideband because I'm waiting with my hand on my ass for some sort of engine management that doesn't require cutting up my pcm harness?

 

[bazooka joe]

where is the egt sensor usually installed (in the exhaust) i would imagine the location is critical?

 

[Jays07MS3]

where is the egt sensor usually installed (in the exhaust) i would imagine the location is critical?

Typically you would install it on one of the runners on the exhaust manifold, whichever one is the hottest. I'm not sure about our cars but usually the #1 cylinder runs the hottest .

And yes our car comes stock with a WB O2 sensor.

 

[oskinosmee]

Typically you would install it on one of the runners on the exhaust manifold, whichever one is the hottest. I'm not sure about our cars but usually the #1 cylinder runs the hottest .

And yes our car comes stock with a WB O2 sensor.

with a dashhawk how do you read it and where sould it be.

 

[Jays07MS3]

with a dashhawk how do you read it and where sould it be.

You can read the WB O2 voltage directly or its equivalency ratio. >1 = lean condition, <1 = rich condition. You can multiply it by 14.7 to get actual A/F ratios. For WOT, high load conditions, you usually want your A/F < 12 or so. Ours are usually around 10 and under because they run so rich.

MSD is supposed to add a direct A/F ratio reading in the near future. They been releasing firmware update a few times a month and the AFR thing in on their TO-DO list.

 

[madeye moody]

Typically you would install it on one of the runners on the exhaust manifold, whichever one is the hottest. I'm not sure about our cars but usually the #1 cylinder runs the hottest .

And yes our car comes stock with a WB O2 sensor.

I'd think you'll be going through k-probes faster if you mount it in one of the runners as well as it wouldn't be representative of the whole engine.
Yes that is going to give you "a reading" of temp in that runner and yes it will read hotter there than if you mount it immediately after the turbine in the downpipe, but unless you are reading heat of combustion right in the cylinder then all of your measurment locations will be secondary anyway.
If that is the case then you may as well measure it in an area that is easier to install, has less exhaust pressure, i.e. less likely to leak, and has lower temps so it less likely to burn out the probes. The rate of cooling in exhaust taken in terms of distance from the cylinder should be pretty much uniform so reading at the Turbine Outlet is going to be just as predictable and more informative. What if you clogged an injector or something on cylinder #2? You'd read normal on #1 but #2 would quickly burn lean and pop that cylinder. Unless you run a thermocouple in each runner with a way to monitor and compare each runner then placing the probe where the exhaust combines will provide the best data. Even one cylinder going lean will raise the temps of the entire exhaust stream so you'll pick it up.
Now that isn't to say mount it TOO FAR away from the head because the further back the less sensitive it will be to temp changes.
As long as you do like someone else advised and install it while the car is at stock settings, then you can measure what the expected temps are in that location and when the temps vary you'll know something is up.

 

[Jays07MS3]

I'd think you'll be going through k-probes faster if you mount it in one of the runners as well as it wouldn't be representative of the whole engine.

Well K-type probes are good for over 1300 degrees Celsius (~2400F) which is around double the temps you'll see at max on an aluminum engine since thats around the melting point. I would demand that the manufacturer of the probe supply the replacements if they were failing at such low temps

Yes that is going to give you "a reading" of temp in that runner and yes it will read hotter there than if you mount it immediately after the turbine in the downpipe, but unless you are reading heat of combustion right in the cylinder then all of your measurment locations will be secondary anyway.
If that is the case then you may as well measure it in an area that is easier to install, has less exhaust pressure, i.e. less likely to leak, and has lower temps so it less likely to burn out the probes. The rate of cooling in exhaust taken in terms of distance from the cylinder should be pretty much uniform so reading at the Turbine Outlet is going to be just as predictable and more informative.

I agree that convenience comes into play when deciding where to install but I would never consider installing a probe post turbine as opposed to pre turbine. I want to know, as close as possible, what the actual combustion temps are, not 200-300 degrees cooler due to turbine energy losses.

What if you clogged an injector or something on cylinder #2? You'd read normal on #1 but #2 would quickly burn lean and pop that cylinder. Unless you run a thermocouple in each runner with a way to monitor and compare each runner then placing the probe where the exhaust combines will provide the best data. Even one cylinder going lean will raise the temps of the entire exhaust stream so you'll pick it up.

Well that would be ideal wouldn't it? To monitor all cylinders the way they do on aircraft engines. But yes, you can also monitor at the exhaust collector but you're reading average temps. For racing applications, you want to tune on the aggressive side so you'll need to know how hot the hottest cylinder really is so you don't do any damage.

Now that isn't to say mount it TOO FAR away from the head because the further back the less sensitive it will be to temp changes.
As long as you do like someone else advised and install it while the car is at stock settings, then you can measure what the expected temps are in that location and when the temps vary you'll know something is up.

I think the most valuable info is the absolute temp anyways, not relative temps. EGTs are mainly to tell you if you're in the "safe" operating zone for your engine. That doesn't change as long as your block/internals are the same.

But regardless of where you put the probe, it is still useful info as long as you're aware of the limitations of where it is located and what the numbers are telling you and what they're NOT telling you.

 

[madeye moody]

Well K-type probes are good for over 1300 degrees Celsius (~2400F) which is around double the temps you'll see at max on an aluminum engine since thats around the melting point. I would demand that the manufacturer of the probe supply the replacements if they were failing at such low temps



I agree that convenience comes into play when deciding where to install but I would never consider installing a probe post turbine as opposed to pre turbine. I want to know, as close as possible, what the actual combustion temps are, not 200-300 degrees cooler due to turbine energy losses.




Well that would be ideal wouldn't it? To monitor all cylinders the way they do on aircraft engines. But yes, you can also monitor at the exhaust collector but you're reading average temps. For racing applications, you want to tune on the aggressive side so you'll need to know how hot the hottest cylinder really is so you don't do any damage.



I think the most valuable info is the absolute temp anyways, not relative temps. EGTs are mainly to tell you if you're in the "safe" operating zone for your engine. That doesn't change as long as your block/internals are the same.

But regardless of where you put the probe, it is still useful info as long as you're aware of the limitations of where it is located and what the numbers are telling you and what they're NOT telling you.

Believe it or not, the probes DO go out more rapidly the higher the consistent temps and pressures are. They'll last just long enough to get you out of warranty anyway.
I just see nothing wrong with measuring Turbine Outlet Temp since the only time the temp will be substantially different anyway is when it is warming up. I also would think that any place you put that probe when it is not in the combustion chamber is going to be relative anyway.
However with that said, there is something to be said for knowing exactly what egt is going into that turbine; especially if the rate of cooling vs. distance from the head is not linear.
Well I do appreciate your point of view as well, thanks.

 

[madeye moody]

Oh, forgot to mention that my last turbo car the temps between the cylinder head and the turbine measured 900C on full throttle runs as the rpm approached 7000rpm. That was with good 12.2:1 air fuel ratio and the engine ran exceptionally well for the 3 years I owned it with a turbo on it before I sold it. That's hot. And yes, the guys with the autometer egt's went through a probe or two. I used a GReddy EGT which was very good quality. I originally had it positioned 3" from exhaust port. I moved it after a while to about 12" from the exhaust port and got better results. On this V6 turbo the 12" from the port gave better readings. I got about 2 years on the probe before it began to read funny and I had to replace it.

 

[Haltech]

Oh, forgot to mention that my last turbo car the temps between the cylinder head and the turbine measured 900C on full throttle runs as the rpm approached 7000rpm. That was with good 12.2:1 air fuel ratio and the engine ran exceptionally well for the 3 years I owned it with a turbo on it before I sold it. That's hot. And yes, the guys with the autometer egt's went through a probe or two. I used a GReddy EGT which was very good quality. I originally had it positioned 3" from exhaust port. I moved it after a while to about 12" from the exhaust port and got better results. On this V6 turbo the 12" from the port gave better readings. I got about 2 years on the probe before it began to read funny and I had to replace it.

Im still trying to locate a place to mount my probe. Any suggestions? I was thinking of just going to the collector since im running a wideband. Since i have this damn EGT gauge which was ordered as a mistake, im going to just use it and fill a hole in the gauge pod.