CHT and EGT Monitoring for CV CARB Tuning

[posplayr]

Katman started this thread which prompted me to also order an

INNOVATE MOTORSPROTS LM-2

http://www.innovatemotorsports.com/products/lm2.php

here is the thread:

http://www.thegsresources.com/_forum...=161304&page=3

Here is what I have on order but am wondering if I should augment this with a set of thermocouples for all four cylinders (either CHT or EGT or just header pipe temp).
I don't want to cut into my headers near the head, but would consider thermocouples strapped to the header or perhaps to the spark plug. Apparently measuring the exhaust gas is distinctly different to measuring the CHT and measuring the pipe heat is something else. From what I read there is in fact nothing significant about the header temps and 100 deg F difference is not unusual for a NA motor.

Thermocouple inputs are usually either : a) under the copper gasket of a spark plug for cylinder head temperature (CHT) or, b) a bung welded into the header to expose an thermo couple to the gas flow,exhaust gas temperature (EGT). or C.) clamped to a primary header tube for HEADER TUBE TEMP.

How much good does any of these do for temp monitoring do for carb tuning? I have been reading about CHT (Cylinder head Temp) measurements v.s. EGT (Exhaust Gas temp) readings. They are distinctly different and a header measurement is probably closer to some combination. I'm concerned that worse than over monitoring, I draw the wrong conclusions from the measurements.

I already have a dual channel FLUKE 50D so I can look at any two channel at a time. I'm kinda concerned about monitoring inside (2-3) cylinder temps v.s. 1-4 temps.

http://us.fluke.com/fluke/usen/Disco....htm?PID=56087

Also there is a TC-4 from INNOVATE

http://www.amazon.com/Innovate-Motorsports-3784-Thermocouple-Datalogger/dp/B001S7PEQE

http://www.innovatemotorsports.com/support/manual/TC4_manual.pdf

Anybody have any experience with GS tuning for CV and can offer an opinion on how useful temperature monitor would be for dialing in CV carbs for the street. I'm planning on checking my GS1150 36mm CV's and have 3 sets of Slingshot 36mm CV flatslides as well.

For example, if I use thermocouples at the header tubes, should I tune for equal temperatures using jetting, timing or both? Will also have O-2 but that is more than likely going to be a combined average measurement.

[FlyingSteve]

Personally, if I was going to do something for tuning, I would buy 1 wideband O2 sensor and weld bungs in to each exhaust pipe a few inches down from the head. A wideband o2 sensor will set you back about 230 dollars, but will give you very accurate readings of your A/F mixture. I used one when I built my turbo toyota celica and it worked well and kept me from blowing my motor from too much boost and not enough fuel.

Just ride around with it installed in one of the pipes until you get that carb tuned and then move the sensor to the next pipe and tune that carb.

[bonanzadave]

Maybe you can glean some info here here.

J.P.I. is one of the leaders in engine analyzers. These airplane engines are typically 4 & 6 cylinders, air cooled, opposed (2 or 3 on a side) and mostly injected but some are carbed. These engines have a fuel servo connected to a mixture control cable to adjust air/ fuel mixture. Thats why the analyzer is so important. Most guys would like to see their CHTs within 25 degrees of each other.

[posplayr]

Maybe you can glean some info here here.

J.P.I. is one of the leaders in engine analyzers. These airplane engines are typically 4 & 6 cylinders, air cooled, opposed (2 or 3 on a side) and mostly injected but some are carbed. These engines have a fuel servo connected to a mixture control cable to adjust air/ fuel mixture. Thats why the analyzer is so important. Most guys would like to see their CHTs within 25 degrees of each other.

Yea I have been finding alot of A/C are doing retty sophisticated engine monitoring. Here is a pretty good explaination if it is true. I was hoping for something Motor or GS specific. Looks like measuring header tube temp and getting an O2 sensor up the right tube would be best.

http://www.jpinstruments.com/edm_930.html

[tejasmud]

Now your speaking my language.

Good choice on the LM2, but did you purchase an LMA3 as well?

Just having a LM2 will work wonders being able to see the actual AFR measurement, but in conjunction with the LMA3 it makes a really nice dynamic tuning package.

If you wanted to measure temperature at all 4 down tubes I think the LMA3 would just need to be programed. It has been a year or so since I read the manual on the LMA3, but pretty sure you should be able to set up 4 of the 5 channels to read individual EGT sensors if desired.

In opinion, for street tuning I would just use the O2 measurement instead of looking into EGT or CHT.

With the LM1 and LMA3 combination I seem to get better information running AFR sensed by the LM1, and with the LMA3 measuring RPM (induction clamp), MPH (hall sensor), TPS (string pot), acceleration (built in), and MAP (built in). Although the MAP is not much use really on normally aspirated engines. I suppose it could be used to digitally sync the carbs if inclined to do so.

I'm currently setting this combination up on the GS700.

E

[bonanzadave]

Ot.....

Yea I have been finding alot of A/C are doing retty sophisticated engine monitoring.

Heres one were working on....Each Cyl gets two probes. 1 CHT & 1 EGT X 6 cyls

Before


In Process

[Steve]

Uh, ... Dave, ... you been working on that one for a while?

The "before" picture is dated THREE YEARS AGO.

.

[TheCafeKid]

Uh, ... Dave, ... you been working on that one for a while?

The "before" picture is dated THREE YEARS AGO.

.

Heh if left up to me to do it, three years would be Me just figuring out what all that rats nest goes to. I hate wiring, and the before pic looks like my own personal HELL.

[posplayr]

Now your speaking my language.

Good choice on the LM2, but did you purchase an LMA3 as well?

Just having a LM2 will work wonders being able to see the actual AFR measurement, but in conjunction with the LMA3 it makes a really nice dynamic tuning package.

If you wanted to measure temperature at all 4 down tubes I think the LMA3 would just need to be programed. It has been a year or so since I read the manual on the LMA3, but pretty sure you should be able to set up 4 of the 5 channels to read individual EGT sensors if desired.

In opinion, for street tuning I would just use the O2 measurement instead of looking into EGT or CHT.

With the LM1 and LMA3 combination I seem to get better information running AFR sensed by the LM1, and with the LMA3 measuring RPM (induction clamp), MPH (hall sensor), TPS (string pot), acceleration (built in), and MAP (built in). Although the MAP is not much use really on normally aspirated engines. I suppose it could be used to digitally sync the carbs if inclined to do so.

I'm currently setting this combination up on the GS700.

E

This is what I have at the moment (should be here this week). As far as thermo couple inputs the LMA-3 only has one. The chips to do the conversion are about $20 buck and you can buy the TC-4 with 4 channels for $100. So the question is how much good does temp monitoring of individual pipes do while riding around. I can setup thermocouples and just use the 50D for two at a time compare. I could even ride aroud on it but it doesnt data log very well .




My plan is to at least monitor:

1. RPM
2. O2
3. MAP (to get an indication of throttle position to coorelate with test plan (1/8, 1/4, 1/2, 3/4 and Full throttle)
4. Accel for power
5. If I can find a cheap speed pickup that would be nice as well.
6. With the TC-4 I would get all 4 Header temps.

[posplayr]

Heres one were working on....Each Cyl gets two probes. 1 CHT & 1 EGT X 6 cyls

Before

The Power Supply guy I ususally consult with is also a pilot and he strongly recommended monitoring exhaust gas temperatures for uniformity between cyclinders with the O2 to get absolute AFR values. I'll probably pick up the TC-4 and some thermocouple wire.

[don]

If you're getting that nitty-gritty with your tune, IMO, the actual combustion chaimber is where you want to gather info from.

I have personally seen grey/brown plugs, black valve stems, white exhaust tubes (only at the first bend, and black the rest of the tube) all at the same time. this was all because the engine was ritch and there was air getting into the exgaust. The ritch mixture was igniting in the exhaust at the first bend where it's the hottest, then "sooting out" furthur down the pipe.

In this case, if I had a CO, Thermocouple, or a headder strap, I would put more fuel to it and be wrong. I believe the spark plug TC is your best choice for getting all 4 ballanced. You have to give it time to change temps after an adjustment, but I think it's a way better indicator of what the "fire" is doing. There is no opportunity for outside influences.

I have seen guys fasion a thermocouple hole into the head to get the actual combustion temp. That info is instant.

[posplayr]

If you're getting that nitty-gritty with your tune, IMO, the actual combustion chaimber is where you want to gather info from.

I have personally seen grey/brown plugs, black valve stems, white exhaust tubes (only at the first bend, and black the rest of the tube) all at the same time. this was all because the engine was ritch and there was air getting into the exgaust. The ritch mixture was igniting in the exhaust at the first bend where it's the hottest, then "sooting out" furthur down the pipe.

In this case, if I had a CO, Thermocouple, or a headder strap, I would put more fuel to it and be wrong. I believe the spark plug TC is your best choice for getting all 4 ballanced. You have to give it time to change temps after an adjustment, but I think it's a way better indicator of what the "fire" is doing. There is no opportunity for outside influences.

I have seen guys fasion a thermocouple hole into the head to get the actual combustion temp. That info is instant.

Thanks Don,
great info.

[FlyingSteve]

So after you are doing spending all this money/time on a 30 year old bike, you could have bought a new fuel injected bike that puts down nearly double the HP at roughly the same displacement lol

Mmmm, the problem with using TC's on an air-cooled motorcycle engine (unlike an aircraft engine, which constantly has air flow over it) is that a motorcycle engine is designed to get HOT. So the temps you see sitting at a red light, won't be the same as what you see driving down the road at 35mph... And maybe not what you see going 70mph. I'm not sure that using TC's on an air-cooled street engine is the best way. The engine bay of an aircraft that uses a reciprocating engine is designed to keep a steady and constant air flow over the jugs (cylinder heads).

I still think the best and most logical way is to use a wideband O2 sensor, mounted a few inches from the exhaust valve.

Also, the main reason that we use CHT's on aircraft is to keep from melting the engines. The engine is surprising important when you aren't on the ground... EGT's are used for mixture setting. But if you are going to go through the trouble of mounting EGT's in your exhaust pipes, then just use a fricken' wideband o2 sensor and you can get a perfect tune with that alone. Nevermind what your temps are, if your AFR is right, your temps will be right.

[tejasmud]

This is what I have at the moment (should be here this week). As far as thermo couple inputs the LMA-3 only has one. The chips to do the conversion are about $20 buck and you can buy the TC-4 with 4 channels for $100. So the question is how much good does temp monitoring of individual pipes do while riding around. I can setup thermocouples and just use the 50D for two at a time compare. I could even ride aroud on it but it doesnt data log very well .





My plan is to at least monitor:

1. RPM
2. O2
3. MAP (to get an indication of throttle position to coorelate with test plan (1/8, 1/4, 1/2, 3/4 and Full throttle)
4. Accel for power
5. If I can find a cheap speed pickup that would be nice as well.
6. With the TC-4 I would get all 4 Header temps.

That's right. The channels could be set-up to run other 5v signal sensors, but there is only one thermo channel.

If you were to want exhaust temps EGT probes would be the most accurate. From my experience with watching CHT it is hard to establish any good metric. It is basically how 'FlyingSteve' interprets what the temps will do. The thermocouples clamped to the down tubes would have a similar affect. One thing you will notice if measuring CHT is the temps will go up or down in regards to jetting changes. Rich AFR it will be lower, Lean will be higher naturally. Never tried 4 CHT thermocouples at the same time, but my guess would be 1 and 4 would be close but different than 2 and 3, which would be similar.


On the Speed pick-up there is some split collar set-ups for around $80 in the 3rd Party Products off the Innovate site. I have one. It is just a hall sensor J-B welded to a plastic screw, a resistor, and the collar has 2 magnets 180° apart. I actually pulled the sensor off the end of the screw and J-B welded it to a fabricated aluminum bracket to place it where I needed on another bike. Had to shim the collar to fit the wheel. If you find another set-up that will work please share.

I'll see if the hall sensor has a number on it, and check the resistor. If they are common parts that could be had from a electric supply it might be simple enough to make.


E

[tejasmud]

Okay here we goes.

Here is the info on the MPH Speed Sensor purchased from Innovate.

It would be simple enough to make your own, being you will need to fabricate a way to mount it anyway.

Picture of the set-up I have on my other bike. It would not bee too hard. Split collars can be found at McMaster at a decent price. Drill 2 holes 180° apart and glue in some magnets. The split collar would need to be aluminum or non ferrous. The bracketing to fix the sensor so the air gap is also best made from aluminum or non ferrous material as well. If it is ferrous it will disturb the sensor.




Picture of the Hall Sensor

55100
3H02A
0717860




This one would work. With it being flanged it might make it easier to mount instead of J-B welding it to a bracket. Probably might find some sensors at lower cost as well.
http://octopart.com/55100-3h-02-a-hamlin-910142


Then here is the resistor.

Looks to be a 4700 Ω +/- 5%

http://www.elexp.com/t_resist.htm



It is spliced from the blue wire over to the red wire.

I’m going to order a few parts for some set-ups. These parts are cheap enough; the hard part is the mounting hardware, which is not that hard. Might look at Digi-Key also.




E