Boy, I would never have guessed...


Boy, that's a load of crock also...
I've run both GReddy, HKS, and Autometer EGT's.&nbsp I've never had a problem with reaction, unless there was something wrong with the EGT before it was installed or damaged upon installation.&nbsp Sure, the O2 sensor is going to read a fraction quicker than an EGT, and all EGT probes have a latency time, but to call them outright "slow" is a bit extreme.


I'd rather shoot for a target EGT than to shoot for a target AFR.&nbsp A max EGT would give you an idea if you're in trouble, period.&nbsp If you're worried about the EGT latency, then compensate a little lower for reaction time - big deal.&nbsp It's a matter of the tuner being able to use the tools efficiently.&nbsp I can tune cars just with an EGT, AFR gauge (narrow band), and a good ear.&nbsp Sure, a wide-band makes it a lot simpler, but a lot of these wide-band "kits" are very expensive.&nbsp I don't find any of the cheaper "wide-band" kits any more reliable than a narrow band EGO with a 10-LED digital display - "wide-band" in my book means a ~$1,000 sensor.



-Ted

 

...quite a raging debate.

Either way, I agree with Ted.

I don't necessarily use the narrow band O2 sensor for tuning. I normally use the EGT and an open ear to knocking. The wideband seems to be a VERY price item when compared to simple ear tuning and a Good EGT gauge.

It has worked out quite well so far since I have yet to blow an engine(while knocking on wood). I have seem MANY cars street tuned with just the EGT and no blown engine's...or fewer blown engine's. Simple math....Good tuner + Good EGT = Fairly well tuned engine

 

When giving advice to novice tunners on a board.. And to tell them that their ear is good enough, is just moronic. I mean come on..

It would be much better to say. Take it somewhere with a wideband and get a good EGT gauge. Make sure the EGT Sensor is about 7 inches behind the turbine and tune for ~900* C and 11:1 AFR..


Just becuase you are confident in your tunning ability. Does not mean it is safe. And my comment abot EGT Gauges was mostly on the fact that one can read ~800* C and another can read ~900*C. Problem is the one running 800* probably isn't reading correctly and is around 900* already.


I mean look at Autometer's quality! their boost gauges can be off buy 5Psi sometimes.


-Zach

 

Maybe in your eyes... but I still stick with what I've said. You need both to tune an engine. A good EGT gauge and an Autometer POS are 2 completely different animals.

I never said that I hated your guts. You've helped me out many times, and hopefully you will in the future. Our personalities do clash... I give a **** if people hate me or not, and it looks like you don't... but it doesn't mean that we can't civilly exchange opinions and information.

Now I'll quote the whole statement "EGTs suck for tuning. Get a wideband... then your EGT will mean something other than "Oh, now I'm running 1400 degrees. Wonder what that means?" Seems to make a little bit more sense now, doesn't it? Please read the entire statement instead of pulling things out of context... maybe, and I say MAYBE, I should have said "EGTs suck for tuning, unless....

Quote:

I never said it was bad to do so. You used some names that have very heavy reputations. You know what...I bet all of them would back me up on the EGT. Which means you were throwing comments out and ASSUMING those people who back your statements up. This is why I jumped all over you when you brought that point up.

An EGT is a precautionary gauge for iginition timing. I bet all of those names would back me up on that statement as well... hopefully someone will jump in here. I have a good relationship with Rotary777, and have spoken with him for HOURS on end. Don knows what he is doing, and he is the one that went out and bought a wideband because the EGT on its own doesn't cut it.. especially with a narrowband o2 sensor... I'm sure that you know that a narrowband o2 sensor is only semi accurate at around 14.7:1 AFR, and anything that strays from that is a stab in the dark... how could you reliably tune an engine on such a crude reading. I'd personally like to see a dyno run, with wideband readings, on a car that you tuned with an EGT and a 1v o2 sensor. I'm not saying that it can't be done, but that engine has more potential in it... hidden potential from the cruddy o2 sensor (opinion... not fact, don't jump my **** for stating an opinion).

Quote:

Sorry to disappoint you Kurgan, this was nothing personal - it was all about warning people that a wide-band is not the absolute authority when tuning engines and AFR

Well, it shouldn't have been something personal, but by outright calling me ignorant, and saying that I don't know what I'm doing, it was made personal. Like I said, I have thick skin. A wideband is not the absolute authority, but it is a required tool in tuning a high performance rotary to its highest potential, and that's a fact.

 

Good point... Besides... in a rotary with open exhaust, at WOT and 20 PSI flowing over 1000 CFM, how are you suppose to hear knock, let alone hear yourself think?

Quote:

It would be much better to say. Take it somewhere with a wideband and get a good EGT gauge. Make sure the EGT Sensor is about 7 inches behind the turbine and tune for ~900* C and 11:1 AFR..

It is ALWAYS better to have numbers to shoot for... and when a novice asks for advice, it certainly helps to know ALL of the things in this thread... and what Zach has just said should have been mentioned long ago, but was over looked by a couple of "dummies" (yes, me too) bickering over wording. And I use the term "dummies" here just because of how the situation was addressed, not knocking on either of our experiences or knowledge.

 

So is 7" past the turbo the best place??? Anthony said when he moved his behind the turbo it was no where near as accurate.

Isnt there a forumla for temp drop per every inch past the exhaust opening? I wonder how the turbo affects that forumla?

So let me make sure I've got this right, its way more accurate when placed as close to the exhaust opening as possible but may cause turbo damage. When placed behind the turbo is isnt accurate but isnt going to kill the turbo either.

Does anyone know how much temp change there is from the exhaust opening to say a handfull of inchs past the turbo???

Thanks,
STEPHEN

 

SPO I think you got it correct.. Best place is as close as you can get it to your exhaust port.. But you chance loosing the tip of the probe. This isn't very common thou gh. Just with cheap sensors I think.


Maybe Reted can chime in on the correct temp you should look for after the turbine. I am fairly new to this and would not want to give out innaccurate info. I believe it is 900*C or 1600*F


-Zach

 

I street-tune all the engine I tune.&nbsp This means they don't run to the ragged edge in terms of tuning.&nbsp You wanna drop names...Hitman has also backed this up whenever it pops up on the Haltech Support list.&nbsp Sure, you'll will not gain the last 10% or so power potential, but I'll take that safety margin on the street.&nbsp You want to find the last bit of power, sure, use a wide-band and tune it close to the ragged edge - I didn't say it wasn't possible.

I use the EGT to tune AFR's on the safe side.&nbsp It's good for what it does, and it doesn't require a $1000+ piece of equipment, which I currently don't have burning a hole in my pocket.&nbsp The AFR gauge is to tell me if it's RICH or LEAN.&nbsp I don't use it for accuracy.&nbsp There's a point where OVERLY rich sound and feels like overly lean with detonation - the car shakes and bucks, and fuel exploding in the exhaust systems sounds notoriously like detonation.&nbsp The EGT starts to shoot up, cause of all the fuel burning in the exhaust - no way you can tell unless you have SOME way of figuring out the AFR.&nbsp The (narrow-band) AFR does this nicely for $30.




-Ted

 

Too much variables, as this has a lot to do with turbo (turbine) design and exhaust system design.&nbsp We can offer numbers as a target, but it's a general temp to shoot for, which you should be adjusting for your application...



-Ted

 

After turbine, I see 760&#176C.&nbsp Mind you, this is a very conservative number, as I don't want people coming back to me saying they blew up their motors cause it was too lean...



-Ted

 

Good deal man. I think we were walking on opposite sides of the same street there for a while The whole time, I was talking about OPTIMUM tuning (which I prolly should have stated...) and you were talking about conservative street tuning... in that case, I agree with just about everything you said

I still think that MY egt gauge reacts too slow. I would really like to see some of the high dollar EGT gauges in action so i could compare... but I only have experience with my Autometer one.... which I will give to anyone who wants to come get it, just kiddin'

ReTed, do you always put your probe behind the turbine? I know that in the manifold is the best place, but for a street car, the downpipe sounds like the best location to me... especially after it has been tuned.

One more thing, would you say that after the car has been semi conservatively street tuned, that the EGT acts as a precautionary tool on a day to day basis?

 

can someone suggest a good EGT gauge? This will be going in the downpipe... 6" behind the turbo outlet. I originally went with Autometer simply because they were in English... Since then (3 years ago), I could care less what scale my exhaust temps are measured in, just as long as they are quick, and most importantly of good accuracy (or as accurate as can be for being 6" down in the downpipe).

 

I've used both the GREDDY and the Defi EGT gauges. They both read the same result on the same car with the same mods. They also read at the same speed(from what I've seen).

I've heard of the A'pexi EGT gauges breaking off in two different cars(FD Okinawa and Dragon).

 

Damn, should've figured that out from the begining!&nbsp It would've save both of us a lot of grief!



Which Autometer probe did you get?&nbsp I bet you got the cheapest one! I just looked in the current Jegs catalog, and I noticed there are several probes available for the Autometer EGT gauges.&nbsp There's an expensive "pro" unit prices almost $200.&nbsp I've used an Autometer EGT once, and that thing reacted damn fast (H22A powered CRX)...dare I say, a little quicker than the GReddy unit?&nbsp I believe this was the "pro" unit, as it had the 90&#176 bend in it.


I tend to put them in the exhaust manifold, unless circumstances dictate I shove it in the downpipe. (i.e. Kouki FC turbo with two exhaust runners, unless you wanna run two EGT gauges!)


Sure, I ain't going to deny that.&nbsp I've had my EGT save my *** numerous times cause the numbers were just not right...
1) Crane HI-6 died so leadings weren't firing - 40&#176C higher than normal
2) Trailing spark plugs wires crossed - REALLY high EGT's under boost
3) Field SFC-HyperR was off - I run 4x720's so it's a bit more fuel than stock 4x550 - EGT was way too cold

EGT's will also change with regards to fuel octane.&nbsp I know a number of people who have ran into "bad gas" which the EGT gauge immediately pin-pointed after leaving the gas station after a refill.



-Ted

 

You're right on the mark Ted. I have the Autometer Ultra-light EGT with the "Pro" probe and it reacts faster than my friend's Apexi. When I bought my first Autometer I bought the bottom line model. The bottom line model is Unbelievably terrible. I would run down the qaurter mile only to see it really start rising after I passed through the traps. With the "Pro" probe I can be idling and when I press the gas I can watch the EGT's shoot up and down very quickly. By the way, I have recently found out from another install I recently did that the "Competition probe is identical in appearance and seems to work just as well as my "Pro" probe, but for less money.
Hope this helps,
Ben


1991 RX7 Turbo
11.8@117mph

 

It was a joke

 

Amen!!

Yep, when I bought this piece of junk years ago, I had no clue that there were different levels of probes, I bought the cheap one... it sucks. So, you're saying that if I cough up the cash for the decent probe, it would be nearly as good, if not better than the Greddy unit? That would save me some dough, not having to buy a new probe AND a new gauge (plus all of my gauges match, and if I change one of 'em, I'll have to change them all because I'm dumb like that )

so, Ben, you're saying that the Comp and Pro probes act nearly identically? I want the best for this setup, so if there is even a slightly better chance of the Pro reading quicker, then I will go with that. But, if the two are practically the same, why not save a few bucks, eh?

Thanks for everyones input!

 

Is that 760C after the turbo or before the turbo(I assume its after)? Someone mentioned placement 7" past the turbo, why would it be mounted to far past the turbo? Why dont just a couple inches past the turbo? At least it would be a little close to the exhaust port.

How far is yours mounted from the turbo?

Thanks,
STEPHEN

 

I use GReddy units cause I have not had any problems with them.&nbsp The one time we split the EGT probe was when we were tuning too lean (over 1000&#176C), and I think the probe doesn't like the high EGT temps!&nbsp Doh!

The Autometer "pro" EGT probe moved super fast - the only problem I have with the Autometer EGT gauges is that 1600&#176F is a bit too low for a rotary.&nbsp I've seen the high side of 900&#176C, which is easily over 1600&#176F!



-Ted

 

This is actually before - in between the engine exhaust ports and turbo, in the turbo exhaust manifold.


I used to have it mounted after the turbo.&nbsp Keep in mind, this is for an FC3S, and I assume you're is an FD3S?&nbsp I've seen 720&#176C running down the 1/4-mile at the top end.&nbsp The Racing Beat 3" downpipe has an EGT bung that's literally 1" away from the turbo turbine exit.


-Ted

 

This has been very helpful in deciding which gauge and probe to get, but I still cant make up my mind where to mount the probe.
In the exhaust manifold seems to be the best place as far as get a good reading, but Im just worried about that thing cracking and a piece of it going through the turbo(which might just be stupidity on my part).
As far as mounting it in the downpipe. What effects if any would having an open wastegate have on the readings at WOT?
Also Im curious if anybody is using some kind of dual setup, to read the front and rear rotor EGTs?

Thanks for the info

 

I found this post to be very informative as well, and to see a couple rounds between Ted and Kurgan

I am not sure I quite absorbed everything I need to about EGT location...
Further away from the exhaust ports is yield slower temp changes and less accurate temps...(assuming the hardware is working correctly)
before the turbo has the risk of sending pieces though the turbine if anything where to ever happen to the prob...
Right after the turbo is acceptable, yet lower temps because of passing though the turbine...??
Due to a Rotary's high temps, a gauge needs to be picked out that will measure the range needed...(1000C or ~1850F)

Do EGT probes go bad/wear out?

Thanks
-D

 

i have a t78 and am running mid 10's AFR under boost approx 14psi and see about 800deg C. my egt is about 3inchs from the turbo in the downpipe.
my 2cents
justin

 

I use the AUTOMETER Z Series that goes up to 1600deg. F , I think it is the "Pro Street " one with the bent sender , it reads super fast and I have the probe about 2" away from the turbine outlet.
I think having a means to monitor changes in the temp. is important thereby raising a "RED FLAG" , knowing the exact temp isn't , well not to me at least ( I could ber wrong ) , if temps are running say 40 deg higher (or lower) any particular day I would notice and realize there might be a problem and check it out.
Can anyone suggest what temp might be good at , say 20-25psi with water injection , and "GOOD " tuning ?.

 

Is the ultimate goal to run the lowest egts?