What exactly does a EG guage do?

[800polaris]

I know that it reads exhaust gases in your pipes, but what is the point of having one?
I just put twin pipes on my 01 800 RMK, and the guy i bought it from also sold me the guage and said "if you have twin pipes, you have to have the EGT guage. Is there a certain temp, i should be looking for ? high or low? Do i need this if i have the stock temp. guage? Or does it just read the engine temp and not the exhaust gas?

 

[cobbycat]

the stock temp gauge is water temp. egt's do measure exhaust gas temp and you can tell if your jetting is good or not by the temp you are running in each cylinder. I'm not sure on the temp your sled should run but it is probably around 1200 degrees max. leaning your engine out should raise the temp, richening it should bring the temp down. just need to pull the magic number ( or real close) on a long pull and your jetting will be good. you can also tell if there is something wrong (after you get it dialed and know what temps you usually run) if the temps vary too much. these will save your motor once you know your max temp and if you watch them.

 

[Rob1334]

Numbers dont mean anything without a good baseline tune, 1200 is nothing depending on where the sensor is located. What they really do is gives you readouts to a proper tune, for example, you get your jetting spot on by the color of your plugs and wash, record that number and that is your tune. f-bomb racing has an awesome guide as far as that goes, google for his website.

Mine runs at 1450 or so all day and couldn't be happier with the tun of my sled.

 

[Modman]

Numbers dont mean anything without a good baseline tune, 1200 is nothing depending on where the sensor is located. What they really do is gives you readouts to a proper tune, for example, you get your jetting spot on by the color of your plugs and wash, record that number and that is your tune. f-bomb racing has an awesome guide as far as that goes, google for his website.

Mine runs at 1450 or so all day and couldn't be happier with the tun of my sled.

What he said^^^ search EGT readings on here, I've linked the Tech stuff on F-bombs site before. Honestly, air/fuel ratio gauge is also needed to accurately determine tune. The EGT will help you determine EGT's at the temp, the A/F ratio will help determine if you are lean or rich and both together will allow you to dial things right in. A/F gauges are nice because you can tune at different throttle settings, EGT's are only a # and baseline data is only as good as the time you spend setting things up. Also, EGT's only tell you when the motor is getting too hot, A/F gauges will help determine jetting and identify when things are too lean before you get into trouble.

The A/F gauge is useful when things change in relation to temp and atmospheric pressure, elevation etc. EGT readings can be mis-leading if you set up on a warmer day at a certain elevation, then next day start out at the parking lot at lower elevation and colder temps. Seen lots of guys squeak pistons by riding in different conditions than when/where they calibrated their EGT readings. If the A/F readings and the EGT's correlate pretty well, things are usually pretty well spot on. A/F gauges are pricey though.

If you are too rich you can spike the #'s by burning fuel in the pipe, which gives you higher readings, can look like you are really lean. I'd be scared of 1450, aluminum's melting point is 1340 F, some of the alloys are slightly higher meaning that 1400's are possible. Where's your probe located?

 

[my mod]

What he said^^^ search EGT readings on here, I've linked the Tech stuff on F-bombs site before. Honestly, air/fuel ratio gauge is also needed to accurately determine tune. The EGT will help you determine EGT's at the temp, the A/F ratio will help determine if you are lean or rich and both together will allow you to dial things right in. A/F gauges are nice because you can tune at different throttle settings, EGT's are only a # and baseline data is only as good as the time you spend setting things up. Also, EGT's only tell you when the motor is getting too hot, A/F gauges will help determine jetting and identify when things are too lean before you get into trouble.

The A/F gauge is useful when things change in relation to temp and atmospheric pressure, elevation etc. EGT readings can be mis-leading if you set up on a warmer day at a certain elevation, then next day start out at the parking lot at lower elevation and colder temps. Seen lots of guys squeak pistons by riding in different conditions than when/where they calibrated their EGT readings. If the A/F readings and the EGT's correlate pretty well, things are usually pretty well spot on. A/F gauges are pricey though.

If you are too rich you can spike the #'s by burning fuel in the pipe, which gives you higher readings, can look like you are really lean. I'd be scared of 1450, aluminum's melting point is 1340 F, some of the alloys are slightly higher meaning that 1400's are possible. Where's your probe located?

Yes, My 670 ran sweet at 1200 to 1250. I would usually run it a little fat at 1150 or so. When doing a good pull you never have time to watch the eg and I knew when I hit 1300 I would be hitting the shop to replace a piston. Temperatures can be missleading at first until you get to understand your engine. You need to check the plugs and wash and compare it to the eg because probes are not consistant due to many things including location and depth into the pipe.

 

[H2SNOW]

nothing to add her

 

[gforce]

im guessin it tells you when yer egs are done

 

[800polaris]

What he said^^^ search EGT readings on here, I've linked the Tech stuff on F-bombs site before. Honestly, air/fuel ratio gauge is also needed to accurately determine tune. The EGT will help you determine EGT's at the temp, the A/F ratio will help determine if you are lean or rich and both together will allow you to dial things right in. A/F gauges are nice because you can tune at different throttle settings, EGT's are only a # and baseline data is only as good as the time you spend setting things up. Also, EGT's only tell you when the motor is getting too hot, A/F gauges will help determine jetting and identify when things are too lean before you get into trouble.

The A/F gauge is useful when things change in relation to temp and atmospheric pressure, elevation etc. EGT readings can be mis-leading if you set up on a warmer day at a certain elevation, then next day start out at the parking lot at lower elevation and colder temps. Seen lots of guys squeak pistons by riding in different conditions than when/where they calibrated their EGT readings. If the A/F readings and the EGT's correlate pretty well, things are usually pretty well spot on. A/F gauges are pricey though.

If you are too rich you can spike the #'s by burning fuel in the pipe, which gives you higher readings, can look like you are really lean. I'd be scared of 1450, aluminum's melting point is 1340 F, some of the alloys are slightly higher meaning that 1400's are possible. Where's your probe located?

The probes are just after the flanges, at the start of the pipe. So i have the boost bottle, pipes, and egt guage. What else do i need ? the guy who i bought these from only had a boost bottle and a egt guage and his rmk ran perfect. he claims 20hp gain. Should i worry about jetting( set @ 3-6000', thats were i do all my riding), and what about clutching?

 

[rwjk0]

Speaking of probes, how far should they be mounted from the cylinder?

 

[Adrenaline Vince]

100mm from piston. If posible if not then where ever they fit and read you plugs then see what your temp is on you egts and make sure thats what it is when you ride various locations.

 

[Modman]

Straight off AAEN website - bottom of the page, right hand side Aaen Performance : Gauges and Tachs for Snowmobiles

1 pipe per cylinder (1 Probe per cylinder) - Mount probe 10" - 12" from piston. This would be for your twin pipes.

2 into 1 (2 Probes) - Install the probes in the "Y" as close to the junction as possible.

2 into 1 (1 Probe) - Install the probe in the pipe 2" beyond the coupler.