POWER / heat generation and cooling

[Jammasta]

 funkytown said:

at 290 odd wkw you can expect the exhaust gas to be pretty freaking hot when your hooning round the track.

Is the exhaust gas hotter at 290 than 200

[gotasuby]

 TURTLE said:

Is the exhaust gas hotter at 290 than 200

Make more power. Get more heat. Physics.

[Jammasta]

Part joke part genuine question.

Couldn't quote then thin out the wall of text for the specific part.

[Jammasta]

 funkytown said:

at 290 odd wkw you can expect the exhaust gas to be pretty freaking hot when your hooning round the track.

For those that missed the point

[grego0o]

 TURTLE']

[quote name='funkytown said:

at 290 odd wkw you can expect the exhaust gas to be pretty freaking hot when your hooning round the track. /quote]

For those that missed the point

I think the point was more that Funky is pushing the limits of his set up at 290KW and running 25psi or whatever and yes the temps will be higher than a shitty VF23 pushing 18 pounds making 200kw...

All factory Flexis in the up pipe have sleeved insides so a Flexi in the up pipe can be okay but only if it is sleeved...

In saying all of the above I had my non sleeved Flexi removed from my up pipe yeserday due to Funkys Turbo going bye bye and mine was in mint condition most likely due to not running higher boost and having lower exhaust temps... I made 310Kw @ 18 PSI on my set up and yes I did just ewank myself

[Jammasta]

I hope you cleaned te keyboard when you were done.

Can someone accurately quantify the heat difference.

Carry on e-wanking people.

[gotasuby]

With a engine putting out say 200kw at 30% efficency you have roughly say 30% also heat. So 200kw of heat. It goes into radiator, out exhaust etc. More power= more heat. It's simple physics

[Jammasta]

 funkytown said:

all i think this proves is that you're an e-wanker. please refrain from dribbling in my build and take your pointless s*** elsewhere.

And no i do not understand how the temp can be so signigicantly hotter. I would have thought that an efficiently running engine would have similar exhaust temps despite power levels, be that @ 200 with smaller turbo, or 290 (your rough power level) with a much larger more efficient turbo, as it isn't working so hard.

[MercuryFree]

 TURTLE']

[quote name='funkytown said:

all i think this proves is that you're an e-wanker. please refrain from dribbling in my build and take your pointless s*** elsewhere.

/quote]

And no i do not understand how the temp can be so signigicantly hotter. I would have thought that an efficiently running engine would have similar exhaust temps despite power levels, be that @ 200 with smaller turbo, or 290 (your rough power level) with a much larger more efficient turbo, as it isn't working so hard.

Are you saying that you think that 200kW worth of output from fuel exploding produces the same heat as 290kW worth of fuel exploding, with the same fuel?

Internal combustion engines aren't efficiently running full stop.

[funkytown]

on a serious note:

You have to look at compressor maps and efficiency islands to understand whats going on turbo side. That to some regard dictates your IAT or intake temps. A garrett like any other turbo can get out of efficiency quickly, the gt30 is around 25+ psi on my build. on a vf thats about 18-19psi for their given flow in lbs/min - which drives the net power expected. Some of this can be offset by a more or less efficient intercooler obviously.

Like gotasuby said at the basic level more power = more heat. You can also adjust you're AFR's to control heat, basically more fuel to a point = lower exhaust temps and lower power, but also reduced tendency to det i believe and you could increase engine timing. The opposite is true for running lean (simply) hotter exhaust temps but more power (generally) and higher chance of det.

perhaps not wholy true but something like a linear increase in power would result in a greater than linear increase in heat, which is critically important to control. I hope this goes to start explaining that i think my statement was justified and not self inflationary.

* I'm no tuner and this is perhaps very over simplified and not 100% accurate but you get the picture.

on a less serious note:

the other smack talk is from guys i hang out with and know personally. I get their humour and its funny. Personally i barely know you and i find your comments (humour) generally tally poppy and not funny, maybe because i dont know you. But then again i dont troll / rark / take the piss when you've got stuff to contribute is because i dont know you and we dont have that report.

[wrx_lou]

The first time they dyno'd a veyron engine it nearly set the building on fire due to the huge amount of heat generated. By your standards are you saying it was inefficient?

[funkytown]

 wrx_lou said:

The first time they dyno'd a veyron engine it nearly set the building on fire due to the huge amount of heat generated. By your standards are you saying it was inefficient?

who you asking, and clarify the question (if at me), and il try to explain better.

[Jammasta]

 funkytown said:

on a serious note:

You have to look at compressor maps and efficiency islands to understand whats going on turbo side. That to some regard dictates your IAT or intake temps. A garrett like any other turbo can get out of efficiency quickly, the gt30 is around 25+ psi on my build. on a vf thats about 18-19psi for their given flow in lbs/min - which drives the net power expected. Some of this can be offset by a more or less efficient intercooler obviously.

Like gotasuby said at the basic level more power = more heat. You can also adjust you're AFR's to control heat, basically more fuel to a point = lower exhaust temps and lower power, but also reduced tendency to det i believe and you could increase engine timing. The opposite is true for running lean (simply) hotter exhaust temps but more power (generally) and higher chance of det.

* im no tuner and this is perhaps very over simplified and not 100% accurate but you get the picture.

thats kind of the epxplantion i was hoping for. Though it still doesnt quite fit with teh idea i have in my head.

[funkytown]

Which bits dont fit? Happy to explain more/different if i know what youre confused about

[Swindog]

Power power = more fuel = more heat being generated

?

I dont think funky e-wanked himself in front of the whole class...cos if i had 290killerwasps I would stand up and e-wank some matrix dribble all over your face Turtle

[grego0o]

 Swindog said:

Power power = more fuel = more heat being generated

?

I dont think funky e-wanked himself in front of the whole class...cos if i had 290killerwasps I would stand up and e-wank some matrix dribble all over your face Turtle

lololol like

[funkytown]

 wrx_lou said:

The first time they dyno'd a veyron engine it nearly set the building on fire due to the huge amount of heat generated. By your standards are you saying it was inefficient?

il have a stab at this regardless.

Every type of energy production has a given heat potential - i think thats some physics rule somewhere. Generally more energy production = a greater amount of heat potential. My language might not quite be right but the heat potential can be in a range higher or lower depending on the energy inputs (internal factors) and the heat control on the energy production (external factors).

As the energy output of a veyron is much much higher than say a 200kw wrx, its heat output is simply much higher regardless of those internal of external factors.

I think in terms of cars, what efficiency does is effects what heat (and energy) might be produced within its normal expected range, depending on the inputs to generate that energy - fuel mixture / amount of fuel, amount of air / pressure, air temperature etc. The external heat control factors are things like intercoolers, block size, water capacity, radiators etc.

It would be wrong to correlate heat to efficiency directly. and i believe turbo efficiency is a different topic to engine efficiency.

Wheres Koom when you need him.???

[Jammasta]

 funkytown']

Which bits dont fit? Happy to explain more/different if i know what youre confused about

[quote name='Swindog said:

Power power = more fuel = more heat being generated

That i can understand, all things remaining equal. eg VF28 @ 170kw would create less heat than @ 200kw.

I was under the impression that changing turbos would change the range of efficiency and therefore heat characteristics. Big efficient Turbo @ 18psi, vs small less efficient turbo (for the car) @ 18psi, which would be creating the most heat.

I would also make the assumption that it is not a direct proportion of heat/power. Eg the exhaust gas @ 290 would not be 30% higher than @ 200. Or would it? or would it only be marginally Higher. Thats what i'd like to know.

Nothing wrong with a little E-Wank.

[funkytown]

 TURTLE said:

That i can understand, all things remaining equal. eg VF28 @ 170kw would create less heat than @ 200kw.

most likely yes. it should create less heat, but there are other input variables like fuel AFR which you can significantly alter exhaust gas temps with.

 

I was under the impression that changing turbos would change the range of efficiency and therefore heat characteristics. Big efficient Turbo @ 18psi, vs small less efficient turbo (for the car) @ 18psi, which would be creating the most heat.

constant variables like AFR, yes your IAT (intake temps) would be lower on the larger turbo, which 'should' contribute to lower exhaust gas temps.

 

I would also make the assumption that it is not a direct proportion of heat/power. Eg the exhaust gas @ 290 would not be 30% higher than @ 200. Or would it? or would it only be marginally Higher. Thats what i'd like to know.

this i dont know but i dont think its a linear thing, what i think you're looking at is not a % based thing but a point at which the metals would melt.

if we made up some numbers:

200kw = 600deg

230kw = 700deg

260kw = 800deg

290kw = 900deg

regardless of the %increase, if the melting point of the flexi was 750 degrees (made up) then i would have detroyed it hypothetically at 230 or 260kw sooner or later. The 290 in that scernaio would just have accelerated its demise, so my original quote saying i destroyed it at xxxkw was a reference point, not a e-wank.

[funkytown]

i do want an exhaust temp sensor (have for some time) - i think the numbers would be frighteningly high.

im not willing to continue testing the melting point of up pipes at reference engine powers. Turns out its a very expensive experiment

[Swindog]

You may even find, the faster you go the cooler it becomes as there will be a balance point in which the flow of cool air (remembering wind chill and dependant on your intake system) will stop heat increase or drop slightly.

Obviously...because if it kept building, your car would splode.

Piping effieciency, flow factors, fuel temp, intake temp (inc air temp outside the car) etc things koom will no doubt correct me on but all in all no matter what the inital heat soak temp will be, there will always be a temp in which it stops, or lessens slightly; compared to your speed and/or power.

[funkytown]

id place speed / air temps in the external heat management variables.

While i agree with parts of what you describe i feel that quickly gets blown out the window when you consider the amount of power (which generates heat) goes up exponentially to achieve higher top speeds, and certainly isn't linear getting to that top speed.

that is, an exponential increase in hp gives a declining rate of increase in speed, which I'm loosely aligning to air speed / cooling.

hehe and to retort my own argument ... thinking out loud, what happens to the experience of the air temp as speed increases. It drops right? so maybe you're thoughts are more correct. (consider a 25deg c day, hop on the back of the ute, and hoon across the paddock - it feels much colder)

[funkytown]

Topic split. hopefully this stays interesting and on topic. partly cleansed thread.

mods feel free to clean more if you wish.

[caspros]

 funkytown said:

on a less serious note:

the other smack talk is from guys i hang out with and know personally. I get their humour and its funny. Personally i barely know you and i find your comments (humour) generally tally poppy and not funny, maybe because i dont know you. But then again i dont troll / rark / take the piss when you've got stuff to contribute is because i dont know you and we dont have that report.

*rapport

[ODB]

Beat me to it Caspros!