Hello everyone:
I've noticed since installing the EGT gauge (about 1"-2" from the head in cyl # 4) the higher temp at which my DOHC '98RS-t works. At just crussing @ 65mph no boost EGT @ 1350 - 1400 deg F.
I've spoken to Elliot and his '02 SOHC RS-t at the same speed and his EGT (in the uppipe about 3" from the OEM header) are around 1200 deg F.
Anybody else have their EGT and please state year and model (SOHC vs DOHC).
Thanks,

Efrain

01 RS, EGT in NA mode, I never got above 1250 degrees. With Turbo, I never got over 1450 degrees. I still broke though. Getting fixed now.

Paul...

After much tuning it seems the optimal value for a Turbo'ed RS is around 1350 while cruising on the highway at 80 mph. That way you will get a good kick when you want it and stil not be to lean.

At 65 mph I am around 1250 with the air to fuel ratio being pretty decent. As for gas milage I have lost some milage around town but that is because of boosting way to much from light to light. He he...

Under full boost I never go above 1500. Anymore and you are starting to run on the edge of problems. Short bursts above 1500 aren't anything to worry about though, well nto tmy knowledge.

99RS SOHC, T3 Turbo and Link Engine Management

When I'm going 100mph + with the pedal peged on a N/A 2.5 engine I get higher than 1500F and the only thing I have is an intake. :confused:

Efrain, I belive we have almost the same setup for the probe (1" to 2" from the head of a cyl.) I'm getting readings anywhere from 1100 to 1400 without boost. Full boost (5 to 7 psi's) it climbs to 1500 up to 1550 @ WOT. I was wondering what is the "redline" and/or critical point for our EGT's; I was told that OVER 1500 is not good and over 1600 your're basically fried.:confused:

'99RS-T SOHC

Mariano
:alien:

pd.- Efra, tenemos que juntarnos 'pa ver como tienes "seteado" tu carro y 'pa que me ayudes con unas cuantas cositas....by the way, FELICIDADES por tu actuacion en el pasado Solo; no pude ir ya que le estaban montando el "Clutch" :devil: a mi carro pero escuche que tu carro corrio k-bron..... Dame una llamadita (787)530-6629

1500+ is normal for closed-loop steady cruising with the stock ECU, as it leans out the mixture for maximum gas mileage.

Under boost, 1500+ is bad news. I see about 1350 max while in boost.

Originally posted by Avenger
When I'm going 100mph + with the pedal peged on a N/A 2.5 engine I get higher than 1500F and the only thing I have is an intake. :confused:

Avenger:
Where is you EGT sensor placed in inches from the head? And...What year is your car?
Thanks,

Efrain

Originally posted by Jon Bogert
1500+ is normal for closed-loop steady cruising with the stock ECU, as it leans out the mixture for maximum gas mileage.

Under boost, 1500+ is bad news. I see about 1350 max while in boost.

There have been some lengthy discussions about this in the past. Most people came to the conclusion that going over 1600F is a big no-no. 1550F is considered ok.

Why is it bad to go 1550F under boost and it's ok to go 1550F N/A when they both produce the same cylinder temps? :confused: :confused:

And hello Jon! :D

Well, hello Kevin! :)

I always assumed it was about stress and margin of safety. If you have high cylinder pressures keeping cool is that much more important. The only reason it can run that lean in low stress, cruising conditions is because the ECU feedback has plenty of time to adjust parameters while playing close to the edge for maximum efficiency. With an NA ECU running boost, BIG safety margins seem to be a sensible tradeoff vs. ultimate power.

I am running 1450 @ 70 MPH highway cruise without boost. If I boost up to 90 or a 100 in peaks at about 1500, however as soon as soon as I go OFF boost, the readout gets colder to about 1350 and than goes back to 1400, once again at 70mph. When I cruise up to 80 or so, the EGT reads out 1450 or so. Are these somewhat acceptable numbers or am I asking for trouble?

Stock 00 RS with EGT probe 4-5" from #3 at 2500-3000 cruise 1500-1575 deg F.

Turbo 00 RS with same EGT probe at 2500-3000 RPM cruise 1300-1400 deg F. Cruise at up to 75mph it does not go higher than 1400.

Just got my turbo done, and while testing it was under boost and EGT was around 1300F (600C) at about 80mph. I noticed during crusing sometimes it gets up around that temp too (like 3rd gear at 35-40mph)...but as soon as I shifted to 4th and RPM dropped, EGT raised a bit more.
So far it hasn't gotten over 1400F (755C) for me, and the tab for EGT sensor was 2-3" on 4th cyclinder header. I was told to adjust and lower the EGT temp with S-AFC if it gets over 1400F.
Okay...heading out to fix my ongoing problems now.

-Benson (Another MY98 Owner)

Originally posted by nativo


Avenger:
Where is you EGT sensor placed in inches from the head? And...What year is your car?
Thanks,

Efrain

MY EGT is right after the two cylinder joins on the mainfold on the passenger side. My car is a 00RS.

Okay here's a dumb one??? i would like to know what the heck is a EGT....i mean im N/A and all u guys talk about is 1500F...i mean is that bad...where do u guys get the readings... looks like something serious...and i sure don't want my N/A motor to go out in flames...cause i'm looking a turboeing my RS!!!!

EGT = EXHAUST GAS TEMPERATURE (Gauge which reads from 0F-1600F, in most cases) via a sensor tapped into header/downpipe, I believe.

I think the guys that are running below 1400 or around it while @ full boost have placed the EGT in the wrong location. I think that it has to be as close as it can to the hottest cylinder, which in our case is #3. 1400 Seems to be a very "cool" reading for full boost on the hottest cylinder - perhaps what you don't know is that your #3 cyl is running 1500F+ while your 4th cyl tap is reading cool 1400... I am not busting balls, just trying to sort this out, because like everyone else I would like to know what the "average" reading is and what the "average" tap location is.

bigbird, you raise an interesting point. Remember that the EGT gauge is giving an everage reading over many revolutions. Having a probe located in the #3 primary may not give the highest readings. In that location, the probe only gets "blasted" once per two revolutions. With the probe close to the #3/#4 junction, the probe will get heated up twice as often, but heated up slightly less each time. Which location results in a higher EGT reading? I don't know, but given the speed with which the needle moves even with a quick reading probe, at best you're getting the average of the last 50-100 combustions.

So, in having said that... -> Seems that the EGT read out is very different on every Impreza, due to the location and slight overall variance. So, as a result of that, I think what you are looking for on the EGT is not an exact mark, but wether you are close to peaking - noting the incorrect fuel/air mixture.

Right--if you're doing a long pull in boost, and the EGTs keep rising as the boost and RPMs increase until you get off the throttle--you've got a problem.

But to recap what I (and others) have said, it just doesn't matter what the EGTs are when the ECU is running the show at part throttle or cruise. But when you get into boost, the EGTs should drop slightly and/or stabilize at a level which is lower than the "max lean" that your ECU allows when out of boost.

(this assumes that your turbo system still allows the ECU to do stuff like that--none of this applies to you TEC-II and Link folks)

Jon-

I have my Link set up so that it acts very similar to the stock ECU. When I'm cruising, the ECU leans the A/F out so the EGT's will be about 1450-1500 while cruising at 80mph. As soon as boost comes on, the EGT's will drop to about 1400-1425 and hold there.

And, when I'm cruising around town, and EGT's are around 1100-1300, and I hit boost, the EGT's will rise, and hold at 1400-1425. I think that the Link does a very good job of adjusting the A/F to my target setting.

Jim

Originally posted by Impreza Rider
Jon-

I have my Link set up so that it acts very similar to the stock ECU. When I'm cruising, the ECU leans the A/F out so the EGT's will be about 1450-1500 while cruising at 80mph. As soon as boost comes on, the EGT's will drop to about 1400-1425 and hold there.

And, when I'm cruising around town, and EGT's are around 1100-1300, and I hit boost, the EGT's will rise, and hold at 1400-1425. I think that the Link does a very good job of adjusting the A/F to my target setting.

Jim

This sounds about exactly what my read outs are.

Just for some perspective, I've seen 1700+ in the Celica at the end of a long uphill straight, with the 550cc injectors working their butts off and the stock A/W intercooler completely saturated. Amen to an iron block and forged pistons!

When does aluminum melt anyway? Around 1900? :eek:

Ah! I see, so that's why the EGT doesn't rise as fast or keep steady when I am under boost, versus when I am just cruising it rises much quicker.

I was testing my car today, cruising at 50-60mph either in 4th or 5th gear. EGT was much higher versus if I am under boost going 50-60mph but in 3rd and higher RPM.

Guess the tuning of AFC (within reasonable numbers in A/F ratio) did apply some effects too.

Ok, CEL is on...gotta check that out tomorrow; that's just TOO common for RS-Ts.

-Benson (Another MY98 Owner)

Originally posted by bensonwrx

Ok, CEL is on...gotta check that out tomorrow; that's just TOO common for RS-Ts.




Fix it with this :D http://forums.i-club.com/forums/showthread.php?s=&threadid=226806

Originally posted by Impreza Rider

Fix it with this :D http://forums.i-club.com/forums/showthread.php?s=&threadid=226806


That's a great way to advertise :lol:
My project costs me waaaaaaaay too much $ already and it's not even done yet; otherwise that's mine :)
Besides, the project of my gf's Honda has started.

-Benson (Another MY98 Owner)

Originally posted by bensonwrx


That's a great way to advertise :lol:
My project costs me waaaaaaaay too much $ already and it's not even done yet; otherwise that's mine :)
Besides, the project of my gf's Honda has started.

-Benson (Another MY98 Owner)

Bah...it was worth a try ;)

I am definetly going to switch to Link management next summer. Yet, I must say that so far, the Stock ECU is working out just fine.

<takes out a large piece of wood>
knock knock knock