Egt?

[shredjim]

I just got a 09 M8 Sno Pro with a speedwerx pipe. Speedwerx gave me the optimal fuel settings for a bondocker box. Boondocker said that without a EGT guage, it is real hard to analyze mixture accuracy. Are most people who use a boondocker box to adjust their fuel mixture also using an EGT? The upgrade for the boondocker box that I need, plus the cost of the EGT make the use of this pipe expensive! Thanks

 

[minet]

you could run one without sure, it just tells you if something might be wrong.
m8 with a single there isnt a ton of fuel change going to happen anyhow ,, some fuel + 6k on

im using an attitude box and used what he recomended at atttude.. pretty no frills map ,, that might just be the box itself , and a bd box might get more fancy /shrug
i know my flatland 700 based BB that uses a bd box has a crazy map. the 800 is -1 accross the entire band then + a little at high throttle then + more at wot

 

[Qreiff]

I use a KOSO A/F guage with my air intake, y & pipe set-up. And yes, you make a good point..............performance costs $$$.

 

[Mjunkie]

Piston wash and plug color is the best way to tell how your fuel/air mixture is. They will never lead you astray. EGT's should be used only as a reference. The easiest (I believe) way is to check mixture at WOT first. Find a good hill and run up it several times at WOT and quickly shut the motor down. Then look with a bore scope and this should be a pretty accurate reading of your piston wash at WOT. Adujst it richer or leaner (whichever you need) at the hi setting in the highest rpm setting on your box. Then do it all over again until it is looking good, then start paying attention to your egt readings (if you decide to buy and use them) to let you know where it should be at. It is a pain in the butt, but is the safest and surest way to get it dialed in to where it should be. As far as adjusting the other rpms, unless you're going to do the exact same thing at all the different rpm settings at lo, mid, and hi throttle positions I'd just adjust them where it seems to run the best at those rpms, making sure your egt's never get above what you found is the best at WOT. I personally know I don't have my other rpm settings spot on to where they should be, but WOT to me is where it matters the most, and I've got the other rpm settings close enough. Just my $.02.

 

[JHG]

There's a lot that goes into your pipe running like it's supposed to. You can't just make it run well at WOT and everything be fine. With a BD box, if you get to much fuel in say the 5000 or the 6700 hi, then when you get to 7800 or 8100 hi the performance won't be there until you get rid of the excess fuel. The M8 has a natural lean spot in the mid range and with my experience you may have to lean it out further to keep the sled from bogging and also so it will run through the different rpm ranges at WOT without any hesitation. You can also run into issues if you have(just an example) 5000 mid to fat, trying to compensate for the lean spot. When you open it up after cruising the trail or across a field you will have to much fuel and at the very least lose throttle response. You can check the plugs but who wants to stop at every rpm range and and pull plugs to look at them. Pulling plugs won't tell you when you have a sudden problem either. If something happens and you see one egt soar and the other stays normal you know you have an issue and to shut it down. There is no way you can tune perfectly with out egts or a/f gauges. $300 for a gauge is cheaper then 1 burndown and your sled will run much better if you aren't taking a stab in the dark at where to add or pull fuel. Speedwerx can give you numbers and they might be close but every motor and setup is different so you will have to make your own adjustments. Save some money and look for a used gauge but cutting corners on gauges is a recipe for a burndown and down time fixing your sled when it's snowing.

 

[triple7]

There is no way you can tune perfectly with out egts or a/f gauges.(Big Hoe) Haha ok, this isnt true. I suppose you will say that all the old outdoor mx 125 and 250 two strokes were dialed in with an egt and a/f gauge?? Ya right. EGT gauge is a good tuning tule and as Big says it can help tip you off if you are having something go south. IMO, I would not buy an EGT gauge to run just a pipe. You just are not changing that much. I would tune the thing by feel and plug readings just the same as everyone did with carburators. Add and subtract fuel to achieve good response and good plug color on a hard pull. An excellent way to check your midrange is come down a fairly steep hill under no throttle for a couple hundred feet. Then snap the throttle and see how it responds. If it bogs try adding fuel first. If that doesnt help or makes it worse, subtract fuel. Fuel injection isnt rocket science. Tune it the same way you tune a carb sled. If you use some common sense and watch your plugs you will get the motor dialed easier that dealing with all of those gauges. Both EGT and A/F gauges can be fooled to read lean when rich and rich when lean. They are not the be all end all. GIVE THE MOTOR WHAT IT WANTS TO RUN GOOD. Make small changes and pay attention to plug color. Dial the thing in and ride it. 1 or 2 rides should get it done. JMO

 

[backcountryislife]

Not to cut on you triple 7, but your statement above is biased toward the guys that have more experience & actually know how to tune!!

If you want to assume that Jim is a badass tuner already (probably wouldn't be asking the question if he was) then sure, he's probably safe just gong by "feel" and sound, but in my first year with a mod I burnt down 3 times because guys assumed I could go by feel, well... I felt it when it siezed, does that count??

For some reason you get two extremes, but little middle ground on here. The EGT is not an absolute neccessity, but it's damn close when you're starting out. It's an insurance policy that makes sure you don't mistake a lean bog for blubbering, or a fat spot on top for lean. It took me 3 burndowns to understand the difference (wasn't a gear guy before sleds much at all, my sled was my first 2 stroke), now I can tell where I'm at by sound no problem but I would gladly buy the EGT's when I started out if I could go back in time.

 

[Mjunkie]

Just to clarify a little because it sounds like I was a little confusing on my statement. I start out tuning WOT, but I DO tune the rest also. Tuning with a BD box is easy because all you do is push a button, but you have so much adjustability it isn't easy. Unless you have advanced the timing and done some other things, you shouldn't run harder and hotter than a long pull at WOT, that is why that's where I start at. Once I have the mixture that gives me a good wash reading at WOT, then I look at the egt's to tell me where my optimal running temp is. With my BB, I had a lot of help from Cutler, because he already knew where my temps should be at, but I guess my main point about the egt's is that they are REFERENCE only!! EGT's don't always accurately tell you what is going on in the combustion chamber. I've had too many egt's that for no apparent reason obviously give me false readings. Why? I couldn't tell you, I'm just saying that nothing can tell you more accurately where your mixture is better than looking at piston wash and plug color. That was my biggest point I was trying to make.

 

[Arctic Thunder]

Other than bone stock with factory warrenty I wouldn't ride it without guages. IMO

I know the "Super" Tuners can hear things, smell things and feel things that the normal guy can't. But I know for a fact if something goes hen $hit mid day you run the chance of a burn down. Not worth it to save $300 on a set of EGT guages. If you plan to tune the sled for the mods it just takes out some of the guessing and backs up your changes. You can see the change rather than feeling it I guess.

IMO

Thunder

 

[moyiesledhead]

After burning down a couple of engines due to failed crank seals I wouldn't ride without an EGT...and my sled is stock. More information is always better than less. Cheap insurance IMO.

 

[Unknown]

Too mod or not too mod!

Tuning oh what joy!! Egt or A/F gauge? Both is the answer. Egt as a reference only. Nobody deserves a burn down!!

 

[Ultra]

I second the "won't run a sled without egt's" crowd. Smoked a few before egt's. Zero burn down's after EGT's, going on 10 years. It's a no brainer.

 

[JHG]

I second the "won't run a sled without egt's" crowd. Smoked a few before egt's. Zero burn down's after EGT's, going on 10 years. It's a no brainer.

It was probably joining snowest and not the EGT's that prevented the burn downs. Didn't you know in snowest world that everyone can tune by ear and by the feeling the vibration in the handle bars?

 

[Ultra]

It was probably joining snowest and not the EGT's that prevented the burn downs. Didn't you know in snowest world that everyone can tune by ear and by the feeling the vibration in the handle bars?

I and my friends consider myself a pretty good tuner but I certainly wouldn't claim to be that good. haha