I guess I don't understand why they wouldn't work, a WOT run wouldn't be a problem, you would have to do one to get the right reading on a plug.

That sensor costs less.

 

I also read the tech info data on the jet4power setup. They admit that it only measures a very narrow range of fuel mixtures.

This gauge and sensor looks to be for when you really can't tell anymore by sound or feel if it's lean or rich....then trial and error at all throttle settings to close in on optimum fuel mixture.

That's what they say anyway....I'm no expert....will this last bit of adjustment to optimum make much difference in performance?

 

Doc,
What settings on the gauge would work the best with that equipment on our quads? Are the settings for best effeciency the same for all engine sizes whether it is a V8 or a V-twin? Is there anyway a Noc sensor can be added to this system?

 

My understanding is that it will work with most fuels and engine types, but not some gas additives,

every car made in the US has these sensors on them, all they really are is a sort of milti meter, the sensor creates it's own voltage. .01 - .03 being lean and .08 - .09 being rich. and the middle is normal. the gauge measures the voltage and gives the reading.

Remember in a car, it's taking an average of all 6 or 8 cyclinders, on ours it would be the average of two, so it should be more accurate.

leaded gas is a no - no for any length of time, like doc said, if you use leaded Race gas, do your jetting then remove the sensor.

I understand it takes a temp of 600 degrees for the sensor to start createing it's own voltage, so a 3-4 wire heated sensor might be the way to go.

 

Just over here browsing, trying to learn about other quads, and I saw the post on jetting. I was surprised to see O2 sensor and A/F gauge talk!!!

In the past 3 or 4 years I have been tinkering with a turbo 3.8L buick motor, basicaly a Grand National drive line for those folks that know what they are. The round gauge in the first post, or one darn close, has been used in Buicks for years. I don't have one myself, they seem (from my asking folks over time) to be a little, well, odd. Given that they just have a few LED's they can not zero in as well on what is going on, they just do not have the segmentation in the display. They are kind of old school, there are things out there now for about the same $$ that are more accurate and have more graduation. They are good, however, if you want a quick spot check and have a place for and extra guage. Plus, for those into it for a little bling bling, the lights look cool

Other than that, if you want to get a little more serious, I would look at the A/F or Pyro guages offered by AutoMeter. I think you would end up with great guage that performes well and at a reasoable price. If I were to do it I think I would lean toward a pyro to measure exhaust temp.

Brent

 

tta583,
If you were to use a pyro where would you install the egt's and what temperatures would be correct for jetting?

 

To answer your question alltoys. Stoichiometric is 14.7 and one would think that this is what you want it set at. Oddly enough, it's not. Smoky Yunick says it's around 12 to 12.5 to 1. I know about 1% of what he knows, and he is dead now, so no one can ask him his thoughts anymore. He gave many reasons why this is so, but I can't remember why. I think one of them was an intercooler effect of the intake track. The others? I just don't know? Maybe someone smarter than me can answer this?

This figure is why they make broad band O2 sensors so you can jack in some more fuel and make a little more power. If they didn't make these, the puter would yank the fuel/air back to 14.7.

I personally like the light guage better than a dig, gauge. Why? I can read it very easy when I'm busy driving the car. Kind of like having a dig tach, the damn numbers are always updating and bouncing around. I guess I'm just old school, or just plain old!!!

As far as the pyro. I ran post and pre turbo. I set the redline at 1,500 pre degrees. Now this is a drag race deal so it does not stay there long, if even get there. Your right on the edge at 1,500 with a good forged piston, and I gave it more fuel when I was just screwing around. Post turbo, I lost around 100 degrees so I set it at 1,400.

I would put the probe as close to the head and you can(within 4 or 5" is fine). The further you get away from the head the more heat you loose and you will have to adjust your max EGT.

One other thought. I read somewere that if running a turbo you should put the probe post turbo. I did not agree with this so I asked why he did this? The answer is a good one. If you run pre turbo and the probe fails where does it go? You got it, right through the turbin wheel!!!!!!!! I think I will change it back to post turbo!!!! Something to think about?

Hope your all well after your accident?

 

Doc,
Thanks I am doing well especially with a new/used toy, lol.

I have my egt's about 2 inchs away from the head, you say 4 - 5 does it make a difference. I went by the instructions sent with the egt's. So far I try to run around 1450 at wot this seems to work well. I did have an oxygen sensor with my EFI it was a requirement with the system to work the program. I am slowly building another one but parts are expensive and there isn't a system that is programable at least one that can be adapted to the quad. My charger is crushed and is a paper wait untill I get tired of looking at it.

Would an antomotive speed shop have this system you talk of the oxygen sensor and meter?

 

Alltoys:

As we dicussed earlier, much earlier! We sledders ALWAYS set up our EGT Probes at the flame mouth on the exhaust side on a 2 stroke. The real point though is to set the probes at a 2 to 6 inch distance down the pipe. Then turn the EGT unit OFF. mess with the jettiing until it is just right via remove the plugs and do a visual. Once you have the plugs at a perfect color ( electrode, ceramic and ground strap) THEN turn on the EGT and that is the reading you will always want to maintain no matter what air temp, elevation or mods you do. In other words, establish your jetting then monitor with the readouts as every setup is a little different and no 2 motors run the exact same temp at the exact same distance from the cylinder.

OK now tell me why I am wrong! [img]i/expressions/face-icon-small-happy.gif[/img]

 

I don't think your wrong, but here is my thoughts.

I wouldn't put mine anywhere in the pipe, I realize that in a car they are right off the heads, and I have had EFI snow sleds and they were close.

I wouldn't want anything in my pipe that would restrict the flow of exhaust. Just like jets in a nitrous system that are inside the intake, they restrict air flow and performance. (when not on Nos).

I think I would mount mine in the muffler where they could still read the oxygen in the exhaust and wouldn't restrict as much flow. just my .02