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My name is Mark Kowalski, I operate www.digatrondirect.com.
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Have any questions pertaining to EGT? I would be pleased to answer them for you. I know there is a vast knowledge, among all you SF readers, from which we can draw from. I additionally have direct contact with the technical staff at Digatron also. So let's talk.

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Discussion Starter · #3 ·
The DT52SL seems to be one of the biggest sellers. It has a lot of bang for the buck.
 

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Isn't it a ETG(Exaust temperature guage not Egt??? I just install a single westach etg on my sled(one cylinder) What is the range that the engine should run in under full throttle, idle and 1/2 throttle.

Thanks for the help guys, looks like a cool new section of the site.
 

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Originally posted by Brendan
[br]Isn't it a ETG(Exaust temperature guage not Egt??? I just install a single westach etg on my sled(one cylinder) What is the range that the engine should run in under full throttle, idle and 1/2 throttle.

Thanks for the help guys, looks like a cool new section of the site.
Rob **** (aka F-bomb who also sells digatron equipment) on snowest has a good writeup on how to use your EGT properly. I'll see if I can find it and cut and paste it here.

Found it:
ESTABLISHING KNOWN READOUTS ON EGTS

{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.

Your welcome Rob **** Digatron Factory Race Support
 

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Basically what it boils down to is you still have to know how to tune your sled without an EGT. But once you know this, you get an inside view on how things are changing from the norm. Say the outside temp goes down, your EGT's go up and you know you might need to rejet. Or say your main jet gets a little clogged and your right cylinder leans out - your EGT temp will change.

Basically you CAN'T just buy an EGT, and then shoot for a specific temp number. You have to corelate your own temp range that is safe from your experience with how your plugs/wash/engine sounds are reporting.
 
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