Might EFI my 1976 RD400 this winter

[rd400canuck]

youre going to get mixed results with just an 02 as well. more data is ALWAYS better.

More inaccurate data possibly  lol.... I'll just have to be intuitive with the data I am given and make some assumptions based on what the engine is doing. Fingers crossed there are no meltdowns.

[rd400canuck]

I think the wise thing to do is get the VAPE on and running perfectly... then get the O2 sensor on and take readings with the carbs and also the EGT's and put them into spreadsheets. I think without them Id be asking for headaches and trouble.

[RDFL]

I think the wise thing to do is get the VAPE on and running perfectly... then get the O2 sensor on and take readings with the carbs and also the EGT's and put them into spreadsheets. I think without them Id be asking for headaches and trouble.

Very good advice.

[sav0r]

EGT is really dependent on a lot of variables. It's super useful in a really controlled environment. It's basically worthless riding around town. I record EGT on a Micron XG Log (both cylinders rd350). It's an outdated but rather high end data logger. EGT data is garbage when you aren't full throttle. Even at full throttle there's nothing to learn unless you look at a various other factors.

Lambda is way more reliable.

AIM Data has some info on O2 sensors for 2ts. I think they recommend a Bosch sensor.

[m in sc]

you're saying data at full throttle isn't valuable? (j/k). a good set of egts work well at steady throttle openings, ie: wot..(or steady cruise) I mean, small airplanes rely on them ....  Ive had mixed results with egts,but usually boils down to install, and quality of probe and gauge. and maintenance of the probe. this being said, its worthwhile. eventually, if done right, you'll have enough data logged to run a static program thats relying only on rpm and throttle postilion.   

Id def set up the motor, carbed w the vape and all sensors installed, and record the data, then use that as a rough starting baseline for the efi.  .02

[teazer]

A few thoughts:
Piston engined aircraft do indeed rely on EGT readings but they are basically operating at fixed throttle for hours at a time and only make small changes to any control in flight. Motorcycles are the opposite end of that spectrum especially in traffic.

Where an EGT does make sense is on a race bike or on the dyno.  The same with a wideband O2 meter.  On the street the guage would be up and down like a kid on a trampoline and almost impossible to read and even harder to interpret.

I ran wideband O2/Lambda/Air:fuel (call them what you will) on a drag bike via a data logger where the throttle was wide open for the whole run and even at that, the variations were interesting.  On an LSR bike, that data would be useful and potentially so in real time. On a road racer, EGT gauges are useful to glance at down a main straightaway which is one of the few times the bike is wide open and for long enough to read.

EGT might be more useful to anyone with long straight sections of road and few LEOs where they could see what is going on, but the best power can only really be mapped on a dyno and then log EGT and/or mixture at peak power as a reference to compare to when jetting for changing weather at the track.

[m in sc]

I agree.  But like said, good for steady throttle openings, like cruising around.  comparing that to wideband at same time will be valuable. Im not saying rely on it-only- not by a long shot.  But it does have valuable data to offer. 

[85RZwade]

This is great stuff guys! School is in session and there WILL be a test.

[scully]

Piston engine aircraft need the egt because the mixture is adjustable from the cockpit and is more of a reference to what you set the mixture at. Turbine engine's are much more dependent on egt.

[m in sc]

yup, I knew that hence the steady throttle opening thing.

[teazer]

Flew in a small plane years ago in the evening climbing over the mountains with a full load and they did a great job of keeping the motor from melting as it struggled with a full load.  Unfortunately the gauges were all visible and EGTs were waaay up there and the headers could be seen glowing brightly.

The pilot would nudge the mixture or what I assume were timing levers ever so slightly to balance the need for altitude against the need to keep the thing from melting. Imagine if that motor had seized at 8,000.  We would have been stuck up there for ever. 

What we are looking for is usable information.  Masses of data is not the same thing.  And it has to be information that we know how to interpret and do something with.

As Mark mentioned, steady cruise where there's enough time to read a gauge and enough knowledge to know how to interpret the information, then it could be useful. I plan on adding EGT probes on my next drag race bike to see what temps get up to but there's no way I could read them at over 100 PMH, let alone do anything about it.

[747drvr]

Piston engine aircraft need the egt because the mixture is adjustable from the cockpit and is more of a reference to what you set the mixture at. Turbine engine's are much more dependent on egt.

actually turbine engines are dependent on ITT and fuel flow thus temperature inside the combustion chamber. EGT is important, but not as much as ITT. but then again im only a newbie 747 captain with 30,000 hours

[m in sc]

i was referring to the hobbyist planes more than anything, piston props. But still. trends on the data will show up vs the o2, and if a head temp is used as well. whos looking at the gauge in this MC application to write a map? (efi) this would all have to be data logged.   

[scully]

i was referring to the hobbyist planes more than anything, piston props. But still. trends on the data will show up vs the o2, and if a head temp is used as well. whos looking at the gauge in this MC application to write a map? (efi) this would all have to be data logged.

The ITT is egt just taken between low speed and high speed turbines.

[teazer]

i was referring to the hobbyist planes more than anything, piston props. But still. trends on the data will show up vs the o2, and if a head temp is used as well. whos looking at the gauge in this MC application to write a map? (efi) this would all have to be data logged.

Exactly.