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Max EGT temps

RMK-King

Super-Moderator
Hey, I have a 08 polaris 600HO with a Digitron EGT on it "probes in Y pipe". What is the max temp you can run up to? I have heard anything over 1250 is going to start melting aluminum. I am running about 1170F Max right now and just want to know what is safe to run.
 
Wash

You nead to look at your piston wash and then reference to your temp. The probes will have different readings depending on where they are on the burn flame comming out of your motor. Look at your plugs also.
 
if you have your egt probes right in the y-pipe 3-6" from the cylinders than the max temps you want to see are probably around 1250-1300max. i run mine around 1240-1260. have one buddy that runs his right about 1300 but that seems a little hot to me.
 
What 6-go said. Temp readings depend on where the probes are located in the flame front.
 
Spend an hour getting your wash dialed in, then see where your temps are at. Helps keeping in tune later once you know where your sled is happy.
For my sled temps between 1225-1275 things are happy with a little more wash than optimal but runs good and does't burn down. I know of a cat that likes 1350.
 
Best way to get your egt number for your is not to ask your buddy. Put a piece of duct tape over your egt gauge and dial in your sled the old fashioned way, with plugs and wash. Once it is running the way you are happy with it, remove the duct tape and look at the numbers you are getting!! Seriously, There are too many variables in the probes and probe placement to use a set number. Kinda like taking slp's jetting chart as gospel. We all know how that one works out! Good luck. :beer;
 
MY SEMI MONTHLY Digatron Post

www.f-bombracing.com digatron tech
{WHAT YOU SEE ON YOUR GAUGE IS INDEPENDANT TO YOUR APPLICATION AND EVEN INDEPENDANT TO EACH CYLINDER ON THE SAME MOTOR}

PRIOR TO SLED TUNING:

TEST PROCEDURE TO ESTABLISH YOUR EGT TEMP RESPONSES AND ONLY IN RELATIONSHIP TO YOUR APPLICATION

When you are dealing with instrumentation you have to have a complete association of responses across the board from YOUR INSTRUMENT with YOUR APPLICATION. {IE} You have to become educated from testing so that you can associate the number figures that are read back on YOUR gauge from each of YOUR cylinders determine the state of tune on each cylinder. Once you have an association of readout numbers and a reference for what that stands for in your application, then you are good to go on with SLED TUNING. Who ever posted that you don't tune a turbo with EGT's reads is absolutely wrong. You can live by the responses of your instrument once you have diligently tested your system and know what state of tune each cylinder is in based on the heat responses shown on your instrument. {also know that in some conditions of tune you will actually see some very high responses while the cylinders are actually spewing unburned fuel...the speculation here is that raw fuel is exploding in the pipe causing this....I have no scientific testing on this statement but we have experienced this over rich condition discovered with plug reading and responses to the instruments during field tests and thus was our conclusion}

TEST PROCEDURE TO ESTABLISH AN IDENTIFIED ASSOCIATION OF # RESPONSES ON YOUR INSTRUMENT FOR YOUR ENGINE: (exactly like we would discover the relationships of READOUTS/STATE OF TUNE on a conventional normally aspirated engine)

SET UP: new plugs, known viable transmission setup, an engine setup with a known safe or recommended baseline and the test facility should be at or near your common riding altitude plus average air conditions that you would encounter (not mandatory but definitely helps) a test track that offers smooth, straight, and long enough run out to maintain a long distance full throttle pull (minimum 30 seconds) plus a notepad is mandatory

(1) Complete warm up to minimum 100* h2o....Sled lifted so that the track is not touching...at a steady idle for minimum 15 seconds (NOTE EACH CYLINDER'S READING..WRITE IT DOWN) kill sled pull plugs and read (most likely no burn pattern here as it isn't hot enough we are looking for moisture conditions on the plug) Reinstall and idle then engage (NOTE ENGAGEMENT RPM) noting whether you have a crisp response or any hesitation. If all is well on too step two. If there is a hesitation retuning of the first carburetion cycle is necessary (fuel air pilots slides) OK we have established our first safe known reading at idle for each cylinder on your instrument.

(2) Sled on snow...hold the throttle to an RPM position 100 below engagement for a minimum of 10 seconds (NOTE RPM AND EACH CYLINDERS READING...WRITE IT DOWN) without changing the throttle position or RPM kill the sled do not change throttle position until the engine is completely off..pull the plugs and read their burn condition (once again low heat range may not have a burn pattern yet but should be wet or dry to tell general state of fuel burn) Retest while then accelerating from 100RPM below engagement through engagement to test for crisp response. ..if all is well move on to the next step. If it hesitates once again look to fuel idle pilot slide and the beginning of needle position....totally depends on the engagement package of your transmission and where that is based on your carburetion package....remembering that we are not necessarily tuning the sled yet we are still associating read numbers to your application. If all is well we have established our second safe known reading at idle for each cylinder on your instrument.

(3) Sled on snow...engage and accelerate to 5000 RPM holding steady for a minimum of 10 seconds CAUTION (observe your instrument carefully and be ready to blurp the throttle in the event that you see readouts over twice what you've seen in testing to this step) if so richen your needle settings and retest...10 seconds at steady RPM (NOTING RPM AND EACH CYLINDER READING..WRITE IT DOWN) kill the sled coast to a stop without changing the throttle position...remove plugs and read their complete burn condition also attempting to see if there is a piston wash pattern (most likely not)....if all is well we have established our third safe known reading at idle for each cylinder on your instrument...move on too step 4

(4) Sled on snow...run at 6,500 RPM holding steady for a minimum of 10 seconds CAUTION (observe your instrument carefully as now you are starting to get an association of what each readout means in comparison to the state of tune for each of your cylinders so if you see readouts significantly over what you've seen in testing to this step kill and coast then double check plug and wash for safety) adjust carburetion settings accordingly and retest...10 seconds at steady RPM (NOTING RPM AND EACH CYLINDER READING..WRITE IT DOWN) kill the sled coast to a stop without changing the throttle position...remove plugs and read their complete burn condition also attempting to see if there is a piston wash pattern....if all is well we have established our forth safe known reading at idle for each cylinder on your instrument...move on too step (5)

(5) Sled on snow..run at full throttle starting for 5 seconds EXTREME CAUTION (observe your instrument carefully as now you are starting to get an association of what each readout means in comparison to the state of tune for each of your cylinders so if you see readouts significantly over what you've seen in testing to this step kill and coast then double check plug and wash for safety) adjust carburetion settings accordingly and retest... 5 second tests until you can keep a steady safe condition then on to 10 seconds at steady RPM (NOTING RPM AND EACH CYLINDER READING..WRITE IT DOWN) kill the sled coast to a stop without changing the throttle position...remove plugs and read their complete burn condition also attempting to see if there is a piston wash pattern....if all is well we have established our fifth safe known reading at idle for each cylinder on your instrument...move on too step (6)

(6) Sled on snow...run at full throttle for a minimum of 30 seconds EXTREME CAUTION (observe your instrument carefully as now you ABSOLUTELY KNOW the association of what each readout means in comparison to the state of tune for each of your cylinders so if you see readouts over what you've seen in testing to this step kill and coast then double check plug and wash for safety) adjust carburetion settings accordingly and retest increasing in 10 second intervals until you can keep a steady safe condition then on to the complete fully heat soaked run at a steady RPM (NOTING RPM AND EACH CYLINDER READING..WRITE IT DOWN) kill the sled coast to a stop without changing the throttle position...remove plugs and read their complete burn condition also attempting to see if there is a piston wash pattern....if all is well you've now associated an exact numerical reading for a given state of tune on each of your cylinders at varying conditions of timing heat and fuel. You can now dial in your two stroke application to a finer state of tune knowing the upper and lower boundaries of heat responses in your EGTs.

Please note that this procedure only encompasses the basics with six steps...there are wide variances in states of tune within each circuit (so many that it is nearly impossible with this type of fuel delivery to identify and correct each one) of the fuel delivery system and many of which will be dangerously lean. When actually tuning the motor it's a very good idea to test in a wider range of RPM positions so that you can discover these dangerous lean conditions in testing rather than by a experienced mechanical breakdown in the field. Often times we will know of that condition, and while the sled performs too expectation, you may simply have to avoid that throttle position in certain conditions. Avoiding consistent throttle position RPM under the full circuit is a good idea even on what is thought to be known safe setups for the conditions of the day.

(FINAL STEP) now you are educated and informed to move on to dialing in your application armed with the knowledge of what each of your cylinders are telling you at any given RPM. Move on to fine tuning your system.

READING PLUGS and MISC INFORMATION ON TWO STROKE TUNING

www.tsrsoftware.com
(excellent plug reading schematic.... copy reduce laminate and carry with you in the field along with small loop or magnifying glass)
www.ericgorr.com
(more excellent reading and information )

Per our discussion if you'll get some plastic wiring loom and individually wrap each sensor wire including the tach/power and tape the wires to the connection parts to keep them from pulling away you'll have a better install and it keeps electrical cross over interference down. I also tape and silicon seal all of mine to keep them more moisture resistant.

Remember power to tach lead to power per instructions….black ground to the engine block or an engine block ground lead. No coiling wires (in the belly pan we run the egt probe lines along the pan or bulkhead then cover with heat tape and it keeps them safe and makes a clean looking install.

Follow the test Sled/Digatron relationship sequence (Establishing known EGT Relationships) enclosed with the unit and you'll be all set to get the most from your Digatron Data Logger.
 
wow have to do two posts because of so many characters.........

anyway...you are already most of the way there so now tie all this in with what you already know and you are ready to rock.

example: you know it won't blow up at where ever you are at right now....so follow this test procedure and really know your temps and what they mean all throughout your power band. Use your ears nose eyes and seat of the pants dyno combined with what you know or expect from your current setup (your reported heat responses at all of the various RPM levels) against expectation IE my sled set up this way should pull consistant and hard to 8150 with me on it during this test...look down see the reports and note it. Bam your done with max RPM vs heat. Do that through the rest and get the most from your buggy. Be able to see clutching issues. Be able to make quick adjustments safely and with positive results instead of guessing. Cheaper faster and better!
What's it say at idle? (is it crisp? note and adjust if not)
What's it say at engagement? (is it crisp? note and adjust if not)
so on and so on until you have a complete known set of reports
carry on...
 
Very intersting, I'll have to go step by step and figure it out. I'm using a koso dig gauge on my 02' rmk 800 and the gauge blinks @ 1000 degress freaked me out at 1st. Now it's time to learn how to use it. B-rad
 
Very intersting, I'll have to go step by step and figure it out. I'm using a koso dig gauge on my 02' rmk 800 and the gauge blinks @ 1000 degress freaked me out at 1st. Now it's time to learn how to use it. B-rad

Your KOSO has an adjustable alarm (flashing), the manual will tell you how to adjust it.
 
Different perspective

I am sure I will get blasted for this but… IMO there is some basic guidelines for EGT temps. It you are using a standard dimension from Piston Skirt to Probe you can run a certain temp range.

I don’t disagree with all the other posts about how to do it right. But all these steps and procedures are needed to get your sled “Perfect” and also to eliminate any liability from the gauge manufacture and the tuner. By continually stressing the “Right” way to do it they dump all responsibility on the owner/tuner.

Very good idea. But back to my point.

Assume you run your probe 4” from the piston skirt single pipe duel probes in Y pipe. If you see 1250+ you are pushing it. General rule of thumb. Now if you don’t want to go through all the steps you better stay in the 1200 range and call it good.

And F-Bomb thanks for your information. I just printed that and put in my file. :)

Thunder
 
If I die at 32* celcius...What if I was looking at a fahrenheit registaring thermometer and didn't know the conversion? SEE MY POINT? I have to know what those numbers mean before I know if I'm in trouble or not.

Another example:
If your gas needle is pointing to a notch but it's not designated as the full or empty notch what am I going to do? Guess! NO
...answer... look in the fricking tank and see what's in there. SAME THING WITH AN EGT exactly! It's a PIA to open the cap and peak down in there so we have a "gauge" to tell us. Your plugs are your hard to see but absolute actual gauge...your instrument is just relaying that info to you in easy to see easy to understand numbers.

ONCE AGAIN GANG, THE NUMBERS THAT YOU SEE DON'T NECESSARILY MEAN ANYTHING UNTIL YOU'VE DONE YOUR HOMEWORK AND ASSOCIATED A STATE OF TUNE FOR EACH OF THOSE NUMBERS AT A GIVEN FUEL/HEAT/RPM LEVEL.
 
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