Where to install EGT probe?

[djsven]

Hi,

I just bought the autometer lunar EGT gauge. I am wondering where do I need to install the probe. Autometer says "For turbo engines to install it 1-2 inches from the turbo exhaust outlet."
But I have been reading about people putting it in runner #1.
So, where does it actually go now?
Thanks for the help.

Sven

 

[Defiant]

Most DSMs put it in #1:

http://www.myzero.com/gauges/egt.html

But some point out it's "better" after the turbine.

 

[DSMJim]

Originally posted by Defiant
Most DSMs put it in #1:

http://www.myzero.com/gauges/egt.html

But some point out it's "better" after the turbine.

I'm an after the turbine guy. Here is why.

I does not matter what the gauge reads as long as when your tuning it doesn't go higher then what your "normal" reading is. Your normal reading in the manifold is likely going to be 1600 deg which is 1400 behind the turbo. Keep in mind that 1600 degrees is the top of the gauge and when gauges get to their maximum or minimum for that matter they are not very accurate at all.

So your tuning at WOT and your gauge is pegged at 1600 where it should be how are you going to know if your having a problem when your already at the maximum your gauge reads? Your not because you put it in the manifold.

Same situation but your probe in the downpipe and it reads 1400 and you have a problem and all the sudden see it creep to 1500, well lookie there you can SEE your problem because you have some room left on the gauge to see it.

The point is the gauge is not accurate at all no matter where you put it so forget what the number says just put it where ever and watch it so that you don't see if change what where ever it is normally. If you wanna put your probe in your exhaust tip then go for it. As longas it reads 500 deg at WOT all the time then your good to go.

Honestly I don't tune with EGT I only look at it when I'm beating my car up on the highway because that is when it likes to really get hot. If I see it go over 1450 deg then I back off. I know to back off because I still have 150 deg of room left on the gauge to see it going on.

Now do you understand why autometer says after the turbine?

 

[DSMJim]

Another thing is people insist on running it in the #1 cylinder saying it's the leanest because it's the farthest away from the feed for the fuel.

As if the fuel in the rail is down to a trickle at the end where that last injector is and it's gulping for fuel and not getting it I have watched cars on the dyno with 4 egt probes on a semi-standard fuel system (stock rail, regular injectors 255 pump like we run) and the EGT were all different but #1 was not always hotter or different than any other runner.

We have whats called a return fuel system which means the excess fuel goes back to the tank. Excess fuel is going back to the tank even at WOT which means there is too much fuel in the rail or the pressure would start to go up. This is even more apparent with a car that has a large fuel pump. As long as your fuel pump can keep up with your motor (and I think we all have that figured out by now) then your #1 cylinder will not be hotter than any other cylinder. The only time this condition might acctually happen is somebody who is running a lot of boost on a small fuel pump. Anybody who is stupid enough to run 20psi of boost on a stock fuel pump is going to probablly see #1 get lean because they are WAYYY past the efficiency of their fuel pump. Assuming that we all know we need a 190 or 255 when running more boost this situation will NEVER happen.

I have seen and checked this on two different cars with 4 EGT probes in front of the cylinders. If anybody has a different experience I would love to hear about it because I'm sure the possibility exists that it could be hotter, just that I have never seen it.

The reason for this post is because I read through the link above about putting the EGT into cylinder #1. Rant off...

 

[cornbread]

I have mine taped into my o2 housing. I put it there for the same reason DSMJim just listed. I don’t use it to tune just to keep and eye on stuff will ripping on the car.

 

[91TalonTSiCT]

While negating the accuracy of the EGT gauge you also revealed an important part of information...Dont tune with gauges meant to monitor!!! Theres computers out there for that reason. Gauges are just the cheaper route to see how your engine vitals are. Simple mods may not need computers, but heavier tuning definitely would require precision and accuracy because youre coming closer to the threshold and something simple can cost you an engine.

 

[billdo_83]

I have mine in my number 2 runner.
Basically because when I bought the Exh Mani it was already tapped for it.

 

[Slappster]

Autometer probably isn't the best egt gauges for the exact reason they only read to 1600. Some more expensive ones read higher I believe. It may help but still as long as you know what your egts should be constant at and if it goes over that then you know let off.

 

[1fast97gsx]

mine is in runner 1 about 2 inches away. Only use it to MONITOR, NOT tune.

 

[TOF]

Mine is dead center where the runners merge. Its where the manifold was tapped by the guy I bought it from. I was surprised to pull out the gauge and see that it only went to 1600! But I guess its better than nothing. I agree it is no tuning tool...just a warning device.

 

[Race94]

ok so where do i install mine??
I have an autometer phantom, like people said before i want it to monitor the car. In wich place is easier to put in?? better reading?

How/where in the o2 should i tap it if so?

 

[jd1828af]

the greddy egt goes up to 1200 C, or somewhere around there. which is over 2000 F. at lest the egt i have does

 

[NewB2dsm]

DSMJIM

i have a a question for you or anyone else.

first one is i understand why your an after turbine guy. But here are my questions. How do you know there is a 200 degree difference from before the turbo and after? You say 1400 is the same as 1600 in the manifold, but how do you know this? That’s the question here is my take on the egt gauge BS.

First off this is all my opinion from what i have noticed with my egt's.

Ok egts are useless; they do not tell you shit. It is an absolute waste of money, almost like a a/f gauge. My reasons behind this are as follows. First one is that there are FAR to many inaccuracies for an egt probe / gauge. Ill explain, First off temperatures will vary by where the probe is located on the manifold. So you can really say oh 1650 is the limit, because of differences in where the probe is tapped can vary temperatures so if yours says say 1500 if you tap it closer to the head or collector it could be reading 1600. And you can’t compare your egts vs another b/c of these reasons.

Use it for monitoring? No, pointless as well. By the time you see the gauge get that hot its too late its already that hot, but things don’t melt as soon as it gets to that temp so i guess its a nice warning. But even with that, you should just skip this step and buy a logger and tune the car with that, and if you think that you can monitor with a logger then well your right, BUT if you tune it right the first time you shouldn’t have to worry unless you get bad gas or something. I could explain my reasons better talking but ill tell you why i think these things...

On a dyno with a wideband + logger + egt. Now making my pulls 18psi rich as hell, egts 1550 wide band says 10:1 that’s rich as shit. Ok go up to 20psi lean it out some. EGTS 1650+, logger 6k 22 degrees timing, wideband 11.2:1 that’s a good tune and timing is good so why egts 1650+ basically maxing my gauge out. Hmmm interesting... Car has been running for over a month like this no problems. My conclusion is that there are just too many factors in determining egts for example, probe type, gauge, the wire used, probe location, probe depth in manifold. Just too many things that "could" be screwing readings up.

Now my use for a egt gauge. Tune it on the dyno with a logger and wideband. Dont look at the egt gauge till its tuned perfect with logger and wideband. When its tuned make a pull and look at your egt gauge, remember that number if its 1200 or 120000 degrees. Now you know that say 11.2:1 on the wideband is 1600 degrees on your egt gauge. So you know when your driving that when you go over 1600 something is wrong and you can pull out the logger and find out. That’s just my position though sorry for the long post. And yes I have a egt gauge and probe.

 

[spoolinawddsm]

Originally posted by NewB2dsm
DSMJIM

i have a a question for you or anyone else.

first one is i understand why your an after turbine guy. But here are my questions. How do you know there is a 200 degree difference from before the turbo and after? You say 1400 is the same as 1600 in the manifold, but how do you know this? That’s the question here is my take on the egt gauge BS.

First off this is all my opinion from what i have noticed with my egt's.

Ok egts are useless; they do not tell you shit. It is an absolute waste of money, almost like a a/f gauge. My reasons behind this are as follows. First one is that there are FAR to many inaccuracies for an egt probe / gauge. Ill explain, First off temperatures will vary by where the probe is located on the manifold. So you can really say oh 1650 is the limit, because of differences in where the probe is tapped can vary temperatures so if yours says say 1500 if you tap it closer to the head or collector it could be reading 1600. And you can’t compare your egts vs another b/c of these reasons.

Use it for monitoring? No, pointless as well. By the time you see the gauge get that hot its too late its already that hot, but things don’t melt as soon as it gets to that temp so i guess its a nice warning. But even with that, you should just skip this step and buy a logger and tune the car with that, and if you think that you can monitor with a logger then well your right, BUT if you tune it right the first time you shouldn’t have to worry unless you get bad gas or something. I could explain my reasons better talking but ill tell you why i think these things...

On a dyno with a wideband + logger + egt. Now making my pulls 18psi rich as hell, egts 1550 wide band says 10:1 that’s rich as shit. Ok go up to 20psi lean it out some. EGTS 1650+, logger 6k 22 degrees timing, wideband 11.2:1 that’s a good tune and timing is good so why egts 1650+ basically maxing my gauge out. Hmmm interesting... Car has been running for over a month like this no problems. My conclusion is that there are just too many factors in determining egts for example, probe type, gauge, the wire used, probe location, probe depth in manifold. Just too many things that "could" be screwing readings up.

Now my use for a egt gauge. Tune it on the dyno with a logger and wideband. Dont look at the egt gauge till its tuned perfect with logger and wideband. When its tuned make a pull and look at your egt gauge, remember that number if its 1200 or 120000 degrees. Now you know that say 11.2:1 on the wideband is 1600 degrees on your egt gauge. So you know when your driving that when you go over 1600 something is wrong and you can pull out the logger and find out. That’s just my position though sorry for the long post. And yes I have a egt gauge and probe.

hmm interesting.

 

[DSMJim]

Originally posted by NewB2dsm
DSMJIM

i have a a question for you or anyone else.

first one is i understand why your an after turbine guy. But here are my questions. How do you know there is a 200 degree difference from before the turbo and after? You say 1400 is the same as 1600 in the manifold, but how do you know this? That’s the question here is my take on the egt gauge BS.

My good friend with a 460whp miata runs an FJO management system. He has two EGT's that plug right into the computer and are logged during driving. He records an almost perfect 200deg change between the collector and 2" after the turbine wheel. Just like you said it will change with distance etc etc.. but i would say 200deg is a descent starting point.

I agree on the EGT being useless for sure. I use it mostly for watching whats happening when i'm hittin it on the highway. On cold nights the car likes to run a little faster and hotter so it's a good warning device for that, but I really could live without it.

 

[Race94]

anyone have pics of where the probe is on the downpipe?
Does it affect perfomance in any way?

 

[greyforestgst]

thats why i got a greddy egt. goes up to 1200*c (close to 2000*f). i stuck it in cylinder 1's runner a couple inches from the head.

 

[Talon4ever]

I think it would make sense to place the probe after the turbo. I would put it somewhere in the o2 housing. Hey, if that is where the manufacturers put the o2 sensor then why not put the EGT probe there. Either way DSMJIM is right. No matter where you place it drive the car normal and then when you drive the car hard just check the gauge and make sure it does not go above the "normal" temp where it usually is.

Today on Trucks though, the guy was installing an EGT probe on a Ford 250 and he recomended putting it after the turbo. He brought out a good point that if something were to happen to the probe, like break off or something, it would destroy the turbo. Makes sense to me but that is just my opinion.

 

[Talon4ever]

Sorry for the mistake, I misunderstood the guy. He actually put it before the turbo. He just mentioned that when you tap and drill for the probe to blow out all the excess metal shavings or they can kill the turbo. I would still put it after.

 

[flinguist]

Here's a recent post from a guy who put his EGT probe before the turbo:http://www.dsmtuners.com/forums/showthread.php?t=116658&highlight=egt+probe

I think I'd put mine after the turbo.

 

[madracer247@aol]

Do you guys think i can get a pic on the egt taped on a dp cause i have my dp off my car right now maybe i can do it well ist off