EGT Probe

[Z()LTAN]

If i were to put my Pre EGT probe in a blanking flange between Pot 5&6 am i gong to get accurate readings?

All pot EGTs should be the same assuming the injectors are good right?

heres a quik pic of the flange

[joel HJ60]

What happens if the Cyl #1 or 2 go bad? Would that make a difference?

Shouldn't be too hard to drill and tap into the middle?

[+dj_hansen+]

Technically, perhaps.. bets place is the in the middle, there is a few pics floating around that you should be able to find.

[Z()LTAN]

the problem is that my turbo manifold is split 3/3 with a web, so at best i can only monitor 3 pots...

[ozy1]

so that rib, divides the manifold so it is basically in half,

why not just run it post turbo, alot of people do without a worry,

[Z()LTAN]

yeah ill put a bung in the dump pipe too

its just pre gives a more accurate EGT reading

In some cases post can be 10deg cooler than pre and post dosnt show spikes as well.

[balzackracing]

yeah ill put a bung in the dump pipe too

its just pre gives a more accurate EGT reading

In some cases post can be 10deg cooler than pre and post dosnt show spikes as well.

Stick it in the dump pipe. While most major engine manafactures (Cummins, Cat, Detroit) mount all their Pyro sensors pre turbo, the difference would be minimal if mounted post turbo. The main purpose of the pyro is to tune the engine, and any EGT's will show mimimal problems with Injectors on the indirect injection fuel system on a 1HZ, this is due the type of fuel delivery system. If you look at the say the electonic control common rail fuel system used in Caterpillars C series engines or the Eletric Unit Injector system used on the 3500 series engines where a failed injector or sealing o-ring can overfuel the engine, then exhaust temps will definitly show a problem. On a 1HZ you are more likely to notice puffs of smoke, rough idle or a miss during running to diagnose a faulty injector or closed up valve than you would be to spot hotter or colder EGT's.
9 times out of 10 hotter than normal EGT's are a result of low boost pressures or excessive intake restriction most likley due to Air filters.

Did you make the manifold to turbo adaptor or did you purches it??
Cheers,
Busty.

[Z()LTAN]

Cheers for the info mate!

I bought the adapter from MTQ here in perth its a no name part but its very very well made.

[+dj_hansen+]

These are pics hdj105 posted on lcool...




From memory that is a safari manifold but dont quote me.

Post can also be up to 200°C cooler, not 10, however there is no definitive number.

[Z()LTAN]

wow thats one straight hole...

that may be a little out of the reach of my floor and hand drill...

Interesting

Cheers for the pic

[Gearhead]

Hey zoltan, just wondering what size bung to put in the dump pipe as my 80 series is off to united fuel injection next week to have the pump rebuilt and wind the boost up and they want me to put a bung in the dump pipe but i just wasn't to sure as to what size.

[Z()LTAN]

depends on the probe

They are usually 1/4 NPT

[balzackracing]

These are pics hdj105 posted on lcool...




From memory that is a safari manifold but dont quote me.

Post can also be up to 200°C cooler, not 10, however there is no definitive number.

Where on earth did you come up with 200deg cooler???? If the pyro was mounted a meter from the turbo then I would belive that, however every pyro I have ever seen post turbo fitted has been with in 2-8 inches from the turbine housing. There are only two places for the heat to be disipated once out of the cylinder, firstly via radiant dispertion throught the exhaust manifold, turbine housing, turbine, and exhaust system. Secondly via radiant dispertion through other gases as it leaves the exhaust tail pipe and is mixed with our air. I have never seen 20 inches of cast steel radiantly disperse enough heat to drop exhaust gas temps from 600 deg to 400 deg, if so I may have to use your exhaust manifold and turbo as part of a new cooling system for one of our 2500hp industrial engines.

[hdj105]

These are pics hdj105 posted on lcool...

From memory that is a safari manifold but dont quote me.

Post can also be up to 200°C cooler, not 10, however there is no definitive number.

Actually, that's a stock 1HD-FT manifold Dan ;-)

The temperature difference quoted is based on my experience running both gauges side by side, identical VDO gauges and probes.

The figure also takes into account the varying response time of the gauges, which is probably the single biggest reason for mounting pre-turbo, as I want to see what the EGT's are now, not when the post turbo probe has stabilised after heating the turbine housing.

Also don't forget the effect of back pressure and any heat lost as the exhaust gas expands and cools when released from the turbine.

[balzackracing]

These are pics hdj105 posted on lcool...

From memory that is a safari manifold but dont quote me.

Post can also be up to 200°C cooler, not 10, however there is no definitive number.

Actually, that's a stock 1HD-FT manifold Dan ;-)

The temperature difference quoted is based on my experience running both gauges side by side, identical VDO gauges and probes.

The figure also takes into account the varying response time of the gauges, which is probably the single biggest reason for mounting pre-turbo, as I want to see what the EGT's are now, not when the post turbo probe has stabilised after heating the turbine housing.

Also don't forget the effect of back pressure and any heat lost as the exhaust gas expands and cools when released from the turbine.

So you have personally measured a 200 deg difference between a pre and post exhaust temp probe whilst you engine was at correct operating temp and under load? Could you post some photo's of your set up and video of the gauges whilst at the above conditions, I would be very interested to take a look.

Have you measured the back pressure of you exhaust system? What type of exhaust system is it and how many inches of mercury did you have as back pressure? The velocity of exhaust gases leaving the turbine housing whilst the engine is at operating temp and under load would cancel out the theory of cooling effect of expanding gas affecting the temp probe as the main expansion of the exhaust gas happens further down the exhaust.

I also still fail to see how the effort of fitting a probe pre turbo is of benefit on a other that a common rail fuel or unit type injection diesel fuel system when a damaged injector is not going to give you enough of a EGT difference to spot a problem. As previously stated, the benefit of a pyro on anything other than common rail fuel or unit type injection diesel fuel system is only for fuel tuning, or intake problems like low boost or blocked air filters.

Please don't be offended, I'm not trying to shut you down, I am very open to discuss this subject and am happy to be proven wrong as it is all a learning experience. I'm a maintenance supervisor for Hastings Deering Caterpillar in one of the largest mining operations in QLD, I have spent much time in product and technical related role, this stuff is my job and I have had a bit of experience.

Cheers,
Busty

[hdj105]

So you have personally measured a 200 deg difference between a pre and post exhaust temp probe whilst you engine was at correct operating temp and under load?

Could you post some photo's of your set up and video of the gauges whilst at the above conditions, I would be very interested to take a look.

Yes, I have witnessed a peak difference of 200c, more commonly 100-150c, however not under a constant load. As I stated, the difference is caused somewhat by the difference in response time and probe location. I'd imagine given a long hill where load and rpm were kept constant for at least 2 minutes (however road testing would never do this), the difference would probably equalise to ~100c or a little under.

We did video the gauges a few years back, but clarity and file size were the issues. Exhaust is 3", and I haven't measured the back pressure for a long time, or since many tuning changes have taken place.

I'm not offended at all, I can only speak of my experience.

[dogbreath_48]

I drilled from the side and through the internal webbing - can anyone see a real problem with this?