Syvecs Forums

Here we induce some knock to shut down one cylinder, max retard limit of 8 degrees initiates a cylinder shut down, you can clearly see through the EGT rate of change that it mirrors the time frame response of the lambda sensor. These are just as fast and therefore totally suitable for individual cylinder control applications

Further to above I high lighted the rate of change (which is what you want to look at) and you can see its the same as the O2 sensor, also it takes 3 engine cycles to show up ~80ms, there is a small filter on this so its actually faster but wanted to not 'dress it up' rather show an A typical example of actual application and what they can do

Further displays why knock control is the first point of combustion control.

One other interesting note is to take a close look at the TIT on action of ignition cutting on gear change, you can clearly see a matching spike in temperature as the mixture ignites at the turbo charger and also this increase in energy gives a boost spike

Slightly off topic, have you measured ODs of various thermal couple sheaths and if so what is the typical tolerance?

I.e is an advertised 1mm sheath 1mm +/-0.025mm or 1mm +0, -0.05mm etc. Looking to machine a custom thermowell plug and i can't find this kind of info so i can specify exact bore ID specs.

rac wrote: ↑Sat Apr 04, 2020 5:47 am Slightly off topic, have you measured ODs of various thermal couple sheaths and if so what is the typical tolerance?

I.e is an advertised 1mm sheath 1mm +/-0.025mm or 1mm +0, -0.05mm etc. Looking to machine a custom thermowell plug and i can't find this kind of info so i can specify exact bore ID specs.

Not sure about others but here is one of my 6mm probes.

cheers, one of the manufacturers got back to me. their tolerances were +/- around the nominal advertised OD.

rac wrote: ↑Thu Apr 16, 2020 2:03 am cheers, one of the manufacturers got back to me. their tolerances were +/- around the nominal advertised OD.

sweet

FYI we use a solid stainless olive and these neck down to my probes, nice thing is unlike others you can remove them and re position with a little technique which is a first.

Here is another example of where to use my donmega probes, as a very accurate CHT sensor (in this case RHT is more apt!).
Some careful machining and you can place them very close to the combustion process, have them totally sealed against tapered seat and yield much more beneficial information than you can through an exhaust gas sample

Why can't we have a probe actually in the chamber ?

Seems it could be very useful. But never really heard or seen it being done.

stevieturbo wrote: ↑Thu Apr 16, 2020 10:16 am Why can't we have a probe actually in the chamber ?

Seems it could be very useful. But never really heard or seen it being done.

Used to race allot of 2 strokes and used CHT and EGT, issue of putting in into the cylinder is if there is enough casting around especially highly turbocharged to keep the strength in the combustion chamber. I can extrude the tips down to 1.5mm diameter, issue is finding a good enough machinist to do the work thus I do all my own That aside sticking these about ~2mm from the surface is pretty good though, tons of papers from the mid 1940's on wards showing this, I know cause I have collected most of them especially around water injection

RICE RACING wrote: ↑Thu Apr 16, 2020 8:18 am

rac wrote: ↑Thu Apr 16, 2020 2:03 am cheers, one of the manufacturers got back to me. their tolerances were +/- around the nominal advertised OD.

sweet

FYI we use a solid stainless olive and these neck down to my probes, nice thing is unlike others you can remove them and re position with a little technique which is a first.

Here are some more details of fitting as a CHT, keep in mind this is from the 1940's so its been done for a very long time, and some of what its used for. Pretty handy