egt's on the ride in

[tburg]

i have 09 m8, speedwerx y and pipe, mbrp can, reeds 2.5 timing key and intake. runs awesome everywhere but trail riding, my egts are between 1000 to 1120, is that too high to me i think it is. thats 5000 to 6800 rpm i have a bd box doesnt seem anything i change seems to bring the temps down. i am going to silent pass tomorrow i'd rather not squeek it on the long trail in. oh ya second ride since i bought and it came with all the mods. thanks

 

[sirkdev]

You know to not keep a steady throttle correct? Vary throttle position frequently. Should be fine. If your temps that you are posting are around FT Sask you will be fine when you get to elevation in the mountains. Really going to have to watch it around home though.

 

[tburg]

those temps were from paradise mine on monday, i was told to vary the throttle position, just a pain in the ass.

 

[bj_lucky]

my m7 will hit 1180 if you keep the throttle at a constant at 6000 rpm. blimp the throttle and they drop to 1000. but i still see 900-1050 even while blimping it the whole way on the trail. i gotta be full on and full off the whole trail to keep it safe.

 

[JoHNI_T]

ya x2 make sure ya blip that throttle,, give it a few WOT stabs and dump some fuel in her keep it a bit more kool,,,,

 

[bj_lucky]

i was told to vary the throttle position, just a pain in the ass.

its better than melting it down

 

[tburg]

ok cool thats what ill do, just needed to see if i was over thinking those numbers thanks

 

[moyiesledhead]

Anything under 1200 "should" normally be safe, but you should still be checking plug color and piston wash to get a baseline.

 

[tburg]

i ll be checking tomorrow for sure.

 

[POWDERCHOWDER]

I used to run between 1100 1200 on the trail and was fine, as stated just burp the throttle.

 

[bj_lucky]

If you had a boondocker box you could make two settings. But I just choose to leave it set up the one way.

 

[tburg]

i tried adding fuel with the boondocker but it didnt matter how muhk i added it didnt change, all that did was when i got to the top it was hard to start because it was flooded. put the numbers back and i ll just burp the throttle.

 

[neilsleder]

It depends on how close your probes are to the pistons to. If your only that high on the trail you shouldn't have anything to worry about. I would only start worry if it's over 1200.

 

[tburg]

the probes are in the y pipe. ya its just on the trail on long climbs it stays in the high 11's

 

[retiredpop]

Anything under 1200 "should" normally be safe, but you should still be checking plug color and piston wash to get a baseline.

That's absolutely correct. Run it for a 1/4 mile at that rpm where you are concerned. Hit the kill switch and lock the track so the engine quits rotating. Now check the plug color. If you have a light check the piston wash as well but piston wash takes a while longer to develop so it is not as accurate. EGT temps are a useful reference but you still need to do the other checks to know where you are at. I used to run up to 1275 on my old sled and never had a burn down. Plugs and piston wash were very good. Pure aluminum melts at 1220 degrees but pistons are an alloy so take more heat. Another cause of your higher EGT at that rpm could actually be a rich condition as opposed to being lean. Some excess fuel may be burning in the pipe thus giving higher readings than what you normally see.

I found something else that is very interesting regarding combustion temperatures. "But combustion is never complete. There remains an unburned boundary layer of air-fuel mixture insulating the metal components of the combustion chamber from the propagating flame front. This boundary layer is in thermal contact with the cool metal whose surface temperature is well below the ignition temperature of the fuel/air mixture and does not burn when the flame front passes over it. This boundary layer is roughly the same temperature as the metal below and acts as an insulating layer preventing direct contact of the metal to the flame. If the flame front touches the aluminum it melts. Your EGT temperature out the exhaust is up to 1600 degrees F. while the pouring temperature of aluminum is approximately 1380 deg. F".

 

[overkill131313]

That's absolutely correct. Run it for a 1/4 mile at that rpm where you are concerned. Hit the kill switch and lock the track so the engine quits rotating. Now check the plug color. If you have a light check the piston wash as well but piston wash takes a while longer to develop so it is not as accurate. EGT temps are a useful reference but you still need to do the other checks to know where you are at. I used to run up to 1275 on my old sled and never had a burn down. Plugs and piston wash were very good. Pure aluminum melts at 1220 degrees but pistons are an alloy so take more heat. Another cause of your higher EGT at that rpm could actually be a rich condition as opposed to being lean. Some excess fuel may be burning in the pipe thus giving higher readings than what you normally see.

I found something else that is very interesting regarding combustion temperatures. "But combustion is never complete. There remains an unburned boundary layer of air-fuel mixture insulating the metal components of the combustion chamber from the propagating flame front. This boundary layer is in thermal contact with the cool metal whose surface temperature is well below the ignition temperature of the fuel/air mixture and does not burn when the flame front passes over it. This boundary layer is roughly the same temperature as the metal below and acts as an insulating layer preventing direct contact of the metal to the flame. If the flame front touches the aluminum it melts. Your EGT temperature out the exhaust is up to 1600 degrees F. while the pouring temperature of aluminum is approximately 1380 deg. F".

ya what he said........lol......it made sence untill the second part......but I'm blonde with a grade 5 education.......just look at my signiture below!

You can come tune my sled! LOL

 

[Modman]

Those EGT readings are likely fine, check your plugs but they are probably perfect. You can tell a lot about the motor from the plug colour and how far up the center electrode the burn postion is. Vary the throttle a little as stated, I don't know too many trails around that you can hold the throttle at one position for minutes at a time, usually a corner or something. I run about 1180 at 6500-6800 rpm. Probes need to be 6-8" from the face of the exhaust piston. I run 1320 at wide open, 1280 at 7500 rpm. I know a guy that runs his 1085 on av gas at 1350.......Most aluminum alloys start melting around 1340 degrees and most say that 1300 is starting to get into danger territory. Some people like Hooper Racing, will not even talk to you about EGTs because they simply don't believe in them. Jet according to plugs and take some fuel out as you go up in the hill or as the temps warm up, use your EGTs to gauge your engine's performance compared to the baseline you set once you correlate the readings to plug colour. Heres how to read your plugs, don't just go off the ground electrode.