Maximum exhaust gas temperature before trouble??
 

Just spent 30 minutes searching for an answer, and nothing found. So, going directly to the forum.

Background. S4 TII with S5 Turbo, RB turbo back exhaust. Otherwise stock including

I just finished installing a digital boost guage and EGT guage. The EGT is set up to give a slashing warning light if the exhaust temperature hits a pre-defined maximum.


Question for your tuners experts. What is the maximum exhaust temperature I should set the alarm for so I know when to start worrying?:confused:

Tune your engine on the dyno, and then set your warning to about 50F above peak. Depending on your setup, peak will probably be about 1500-1650F.

Thanks.

By the way. I forgot to mention that my temperature probe is located across from the O2 Sensor. I know, better if before the turbo's. But, limited resources lead to that conclusion.

I did a Google search and found the following from a 3rd Gen discussion who also has his sensor across from the O2 sensor.

1) Idle (warmed up & O2 .80 -
- 450C
2) City driving (< 60
-550 - 650C
3) Highway driving (65-80 mph @ 0-10 inches/hg vacuum) - 700 - 760C
4) Banzai Runs (Max boost through 3rd & 4th / O2=.82-.84) - 780 - 820C

The exhaust system requirements of a rotary engine are notably different from those of a four-stroke reciprocating engine. With rotary engines the exhaust gas temperature is very high - approximately 1,700° -2,000°F at full throttle and high RPM for a 1971-95 peripheral exhaust port engine or about 1600°F for a Renesis (RX-8) From Google search

mild setups/hybrid turbos limit is about 1650F(900C), higher end builds/T04Z-35R-TD06-s366-etc pushing over 450whp will reach 1800-1850F(980-1010C) on pump gas. should not really be going over those figures unless ambient temps are scorching. beyond that the game changes as most go with alcohol fuels which step back down in EGT and ramp up again.

sooo you felt the need to revive a 5 year old thread with a google search?
awesome

Who cares. I thought it was helpful

I agree. He took the time to see if there was already a thread on this subject, then contributed his information there rather than create thread clutter.

I applaud that effort, and it has nothing to do with the fact I happen to be the one that started this thread.

we've actually since learned a couple of things.

the EGT in the downpipe, is a little less useful than in front of the turbo, but here are some figures.

a CAT wants to see less than 650C at peak, since this is fairly cold, it will leave you plenty rich.

a stock ECU car will do about 720C peak.

Yes because I have few friends the have problems with E temp. Also i put google search because I got the info from a Mazda Japanese page and one of my friends translate for me, so I think is a good source. Everything the we can do to keep the few last Mazda I think is worth it.

i was measuring about 950C during cruise, pre-turbo, at 14.7 AFR. get into 10-15 psi boost and it would drop down to 700's at 11.0 AFR. factory manifold with a p-trim hybrid, 3" straight exhaust

im no expert, still learning on EGT tuning, but if it is tuned correctly, the AFRs should be lowest at high engine loads, no? too lean or too rich = higher EGTs

The EGT drops at high engine loads because the mixture gets richer at the same time.

you should do some reading, but generally EGT is highest just lean of peak power, and then it gets colder on either side of that.

on the rotary we like to be rich of peak EGT because things melt at the peak.

I've been running around 1390 to 1450 at a highway cruise 5th gear before turbo. Haven't got into boost yet as I'm still breaking her in.
It's an all brand new S5 TII housings and plates with S4 TII Rotors, S5 Turbo, racing beat Rev II full exhaust, stock intake. Usually in the 900f at ide.
I thought highway cruising was a little high. But maybe not being before the turbo.

my cruise the same so i think its no problem only i have a hybrid one housing s4 another s5 . intake RB carb with a 750 holley