Relationship between ambient temp and EGTs

[troopymad]

For those of u that have a pyro and watch it all the time
What u noticed happens to the temp when the ambient temps change?
I have a turboed 1hz and been getting 300
Degrees C at 100 km/h on the flat , ambient temp at around 24 degrees C.
Does that mean at 40 degrees C ambient I will get 320 ?
Is it a direct relationship?

 

[Dougal]

Generally yes. But I've not noticed much change at all with temp, or rather the 20C or so variation I get is within the normal range that it varies anyway.

 

[mainlander]

I have not noticed much difference between Summer (24-30*C) and Winter ({-}2-5/6*C) here, I think if I had a digital EGT gauge maybe I would notice 15-20* difference, but analog I don't see much changes between the seasons when the air is colder (less dense +/-)

 

[troopymad]

Ok so it should only go up or down the same as the ambient temp

Thanks

 

[DanS HJ-45]

Ok so it should only go up or down the same as the ambient temp

Thanks

Not exactly. You are compressing air (assuming a turbo) and also compressing the heat latent in that parcel of air.

Not exactly the same, but fairly close. If it's 20 degrees warmer outside, my EGT is probably 25 degrees hotter. Barely perceptible, but definitely real.

Dan

 

[VTCDN]

My question would also be , Intercooler Air to Air ? also would have a factor.

VT

 

[troopymad]

Vt
Now ur taking some calculations

 

[crushers]

although in theory it should make a difference i have yet to see a difference at all due to ambient temps ...

<now, i have noticed a difference between a wet day and a dry day>

 

[VTCDN]

No troopymad.

You asked a general question , If someone answered "yes Big difference" , but never said that they had a Intercooler / Aftercooler (Air -2- Air ) style . Your question would be answered with a flaw.

Then again , Do you have a cooler installed ?

As what Dan Posted "You are compressing air (assuming a turbo) and also compressing the heat latent in that parcel of air." and what Crusher posted (dew Point) "<now, i have noticed a difference between a wet day and a dry day>" .

All above Makes a difference to the EGT. The amount of boost / compression of air charge is the major temp rise , dew point (amount of water) adds the second, plus there's the altitude factor. Standard day sea level baro's is whats normally the test readings are referring to. (aircraft turbine engines )

Has anyone ever used temp senders and readings of the 4 places I would use ? just for temps , sized my intercooler this way..

Outside air temp , air box / filter inside temp feeding turbo , air temp of charged / boost air , This one if you do have an Intercooler is air after cooler , and now the EGT ..

No calculations, just a few temp probes . My datum is just off sea level (+300' ,100M) ..

I was surprised at some of my fooling around .

VT

 

[Tapage]

few basic ( non cientific ) observations ..

we have really hot days down here last week I jump in my 80 ( that was under sun from 8 AM to 2PM ) and my analog temp gauge said 150°F

Back to the thread in a non turbo diesel engine .. change in performance and EGT are dramatic from fresh morning to noon .. same from fresh dryu day in summer to hot humid day in our rainy season.

Rolling around traffic wont help anything at all talking about EGT's ..

 

[Dougal]

The other thing with EGT's is cars run easier in the warm so the engine load is a fraction lower than the same speed in the cold.

Air is less dense and a little easier to push through, all oils are a little thinner etc. All these lower the engine load and mitigate the rise you would see in EGT from warmer intake air.

 

[troopymad]

Now it's clearer in my head
If just the ambient temp changed then I could see close to 1 for 1 increase
But there's a lot factors changing as a result of the ambient temp change
Humidity
Air presure
Temp
Different seasons bring about different conditions
Also it's a 78 series 1hz turbo . I love watching the pyro

 

[Z()LTAN]

if you were to add 20deg and 20 deg you would only have 20deg...

same as if you were to add 15 psi and 20 psi, you will only still have 20 psi.

 

[troopymad]

Now u lost me tom

 

[eleblanc]

although in theory it should make a difference i have yet to see a difference at all due to ambient temps ...

<now, i have noticed a difference between a wet day and a dry day>

Probably In theory it should do a small difference but i've never notice a impact on my EGT due to outside temp.

as the air temperature increase its volume does also. But cold or hot it is the same volume that is pumped through the engine. So how does that impact in the explosion i'm not too sure.

BUT; I have notice a good difference in EGT when my water temp goes high.....like over 210 deg F, then the EGT starts to climbs. If you are getting higher then usuall EGT in hot weather, install a mecanical water gauge showing water deg

 

[Tapage]

IMOP hot weather = hot day = less O per volume = less Oxigen to be burn/used by the engine = more unburn diesel = higher EGT's