sperry's EGTs

[MikeK]

Originally Posted by sperry

Is it wrong that my car cruises under light throttle at 1500 deg F egt?

Where is the sensor exactly? What temp do you see at WOT?

I see about 650 - 700 C while cruising around (around 1200 - 1300 F). Mike W. set the alarm on my gauge at 850 C ( about 1590 F), and I have never seen temps that high, even at auto-x.

[sperry]

Originally Posted by MikeK

Where is the sensor exactly? What temp do you see at WOT?

I see about 650 - 700 C while cruising around (around 1200 - 1300 F). Mike W. set the alarm on my gauge at 850 C ( about 1590 F), and I have never seen temps that high, even at auto-x.

Probe is in the cyl #1 header pipe about 4 inches from the outlet. I don't think my temps ever got much above 1500, but they were certainly parked there at partial throttle, 5th gear, on the freeway (at about 55 to 60 mph). I'll check the peak readout next time I'm in the car.

[Dean]

That sounds high for a low torque cruising. In the head of summer, mine runs low 14s. Same location I beleive (Your old headers) I wouldn't think the 2.5l should be hotter than the 2.0l

Should be closed loop, so maybe you are a bit lean?

[sperry]

Originally Posted by Dean

That sounds high for a low torque cruising. In the head of summer, mine runs low 14s. Same location I beleive (Your old headers) I wouldn't think the 2.5l should be hotter than the 2.0l

Should be closed loop, so maybe you are a bit lean?

Your car's sensor is in cyl #3 (the one that tends to run lean). Since I've got fuel rails, I don't believe I have a particular cylinder that's prone to running lean. Also, I'm running jet-coated headers, so they might be holding a bit more heat... but I'm not really sure about how much difference that makes.

You're right about being in close-loop. Car could be running lean, but that's probably not a big problem since it's low load... though that might explain the odd hesitation I've noticed around 4k rpm under partial throttle... I wonder if I've got a little knock correction going on? (I still owe MikeW a data log of the hesitation, but I didn't want to try to do it in the freezing rain on Sunday.) At WOT, my egt's actually decrease, IIRC.

[sperry]

<thread split into its own tech post>

[Dean]

Originally Posted by sperry

Your car's sensor is in cyl #3 (the one that tends to run lean). Since I've got fuel rails, I don't believe I have a particular cylinder that's prone to running lean. Also, I'm running jet-coated headers, so they might be holding a bit more heat... but I'm not really sure about how much difference that makes.

You're right about being in close-loop. Car could be running lean, but that's probably not a big problem since it's low load... though that might explain the odd hesitation I've noticed around 4k rpm under partial throttle... I wonder if I've got a little knock correction going on? (I still owe MikeW a data log of the hesitation, but I didn't want to try to do it in the freezing rain on Sunday.) At WOT, my egt's actually decrease, IIRC.

Well, the lower tems a WOT are good. And yes, closed should be a little leaner, but not so much that temps are high, and you might be getting some detonation.

I would agree it is time to get some logs for closed loop.

[cody]

1500* doesn't sound very excessive. The 2.5L can handle slightly higher EGT's according to Ed. I also see 1500 every once in a while on the freeway (slightly uphill in 4th or 5th) but 1300-1400 is more common for me. I put my probe in the casting button on the manifold.

[sperry]

Originally Posted by cody

1500* doesn't sound very excessive. The 2.5L can handle slightly higher EGT's according to Ed. I also see 1500 every once in a while on the freeway (slightly uphill in 4th or 5th) but 1300-1400 is more common for me. I put my sensor in the casting button on the manifold.

It's not an issue wether or not the motor can "handle" the temp. It's a question about how lean my car is running in closed loop.

[Double Phister]

Originally Posted by sperry

It's not an issue wether or not the motor can "handle" the temp. It's a question about how lean my car is running in closed loop.

got access to a wideband?

What does your timing look like under those conditions?

[cody]

Originally Posted by sperry

It's not an issue wether or not the motor can "handle" the temp. It's a question about how lean my car is running in closed loop.

Sorry, I thought EGT's were a direct product of AFR's.

[doubleurx]

Scott while I posted your car is HOT, that does seem high. Mine runs at low throttle betwen 500-650 and on the hot side between 700- 800 max. At RFR on that day my car was running hot it still only peaked at around 875.

[Dean]

Originally Posted by doubleurx

Scott while I posted your car is HOT, that does seem high. Mine runs at low throttle betwen 500-650 and on the hot side between 700- 800 max. At RFR on that day my car was running hot it still only peaked at around 875.

Where the heck is your EGT? That sounds like all the way back at the up-pipe or further back... Oh, unless your guage is in celcius! 800°C = 1472°F

[Kevin M]

Originally Posted by cody

Sorry, I thought EGT's were a direct product of AFR's.

Mostly, but timing, boost pressure, and ambient temp all affect it.

[doubleurx]

Originally Posted by Dean

Where the heck is your EGT? That sounds like all the way back at the up-pipe or further back... Oh, unless your guage is in celcius! 800°C = 1472°F

Yes Dean C instead of F.

[GST Mike]

To be honest guys 1400-1500f while crusing at low load on a hybrid is nothing out of the norm, STI's will cruise at 1400F all day with WRX's being a little cooler.

Scott, would love to get a log of the hesitation mate. Dont make me have to drive up there to get it

Mike

[sp00ln]

I though(t) things started to melt at 900*c??

[GST Mike]

Originally Posted by sp00ln

I though things started to melt at 900*c??

Sustained I would imagine they do, I think we're talking nearer to 800 though.

My 2.3l Hybrid cruised around 1400-1500f and to be honest I made 900c look like nothing when racing it (1800f) although this was a little bit of an extreme setup and would not have applied to a street car.

Mike

[sp00ln]

Oh, something was telling me that 1400*f = 900*c

[AtomicLabMonkey]

It varies depending on carbon & other alloying material content, but steel generally melts around 1300*-1400*C (2370*-2550*F). Mechanical (strength & ductility) properties change at much lower temperatures.

[Double Phister]

Aren't the sodium filled valves supposed to help or at least increase the resistence to heat? I know that doesn't help with everything else that is exposed to those temps.

With a standard stage 2 StreetTUNER map I was hitting 900C on some 4th and 5th gear runs. After reducing the boost into a more turbo friendly level I might see 825ish. VF39 = flame thrower.