We measure temperature INSIDE the combustion chamber (on different fuels) 

I believe the highest temperature actually occurs in the combustion chamber, but that temperature is only there for part of the cycle, probably mostly in the power stroke. At other times during the cycle, the temps in the cylinder can be quite low. Unfortunately, the probe for the pyrometer has far too much thermal mass to indicate instantaneous temperature, so what you are reading is the average combustion chamber temperature. I would expect that engineers probably have some way to measure the actual instantaneous temperature and plot it out on a graph, but I doubt such instrumentation is easily available, and I'm quite sure it would be very far from cheap. Regardless, it was a very interesting experiment, which is not a surprising thing at all from the garage 54 crew. These guys are always trying something interesting.

this is unironically one of the best engineering automotive channels out there

Fresh fuel and fresh air are obviously cooler, and also most engines are water cooled and those combustion chambers have coolant running through them. Exhaust manifolds are only cooled by ambient air so they will reach much higher temperatures.

It might be because LPG is already a gas, whereas gasoline is still a liquid vapor which takes some energy to turn into a gas which lowers the temp.

One thing I liked about propane setups was how clean the oil stayed. You'd always have new looking oil.

If you can, do this test again but use gauges with less range so it's more responsive to small temperature increases. Enjoy your channel.

for anyone wondering, i have once tuned e39 m54b28, on 1.3bar of boost it had like 760°C in exhaust, but on LPG on 1.5bar EGT was like 580-600° (AFR much richer) but it had more power and egt was lower :D many say lpg cracks valves and destroy engines, but if you tune it properly (with wideband O2 and also have close loop in programable ECU) its much better than regular gasoline... also LPG pressure reducer for 500hp only costs around 200€, we used stock lpg ecu and lpg injectors, so once it was tuned on programable ecu (Plug and play ecu) on gasoline, we switched to LPG and all i had to do was pull out fuel so we stay around 0.68-0.75 lambda.. due to more (mass or molecular weight) of fuel (lpg) injected, it made more boost by those 0.15-0.2bar and pulled much better due to higher boost (but low end/spool was better on gasoline, i think due to ignition timing, as lpg has higher octane it burns slower and would need few more degrees to make same torque/power in spool up)

The sensor being screwed into a water cooled hunk of aluminum probably has something to do with it

In the 90's you could get a see through spark plug that was made with glass where normal plugs have the white ceramic . With this glass spark plug you could tune a engine perfectly as you had a colour chart to for correct burning and you could check if all cylinders got the same air and fuel mixture . This colour chart also state what the combustion chamber temperature could be . A blue colour was the near ideal combustion flame

The cooler liquid should cool down the combustion chamber. The same goes for nitromethane cars. In fact nitro is so cold that you don't even need to run radiators on the drag strip

Your channel is awesome! I am so glad I accidentally found it.

Chamber tempeture is actually much higher, but just for few miliseconds if even maybe that... In short because there is too fast exchange of cool mixture and the hot fumes that go out of the exhaust, so the probe does not have time to read it, thats why under load you have seen the higher tempeture because at more amount of fuel the burn took much longer to push the piston back down so there was much longer higher tempeture time, thats why if you reved it the tempeture fell bacause the probe was cooled of by the cold mixture coming in. The number that you see is an AVERAGE OF THE TEMPTURES THAT HAPPEN IN THE CYCLES , compresion and the burn is somewhere in ballpark of 600°C and the air/fuel mixture intake that can be max 50°C I would say.

I used to work on Propane converted vehicles, there is no lubricating or cooling properties to Propane, and its hot burning so if you didn't replace the exhaust valve seats the valves would wind up sinking 6-8 mm into the heads.

Could you try this with ethanol or some gas/ethanol mixture? Ethanol is used for its evaporative cooling effect being 3 times as strong as gasoline. And it runs richer ,stoicometic is 9:1 compared to 14.7:1 for gas so even more cooling. So remember that when adjusting the carb.

🎉 Proof of thermal dynamic efficiencies 😂

I think the exhaust temp is 2x hotter than internal temperature because in the engine, there's oil and coolant, cooling the engine. When it comes out of the exhaust, there's little to no air cooling it off, so it's hotter than the internal temperature

I have a Fiat 125. Year 1968. soo i love your Lada

Adjust the ignition timing so that you get a large amount of pre-ignition knock then check the temperatures again

Exhaust only has hot gases flowing through it, while the combustion chamber is pulling in cool fresh air regularly- it makes sense that the chamber is cooler than the exhaust.

Now do diesel please

Try balancing a car while driving with only two wheels - front right and rear left or front left and rear right. Try making brake shoes which make contact with the tread on the tires, and test stopping distance against disc braking. This is how some minibikes have their braking set up.

Excellent video! Is your version of 100 octane oxygenated? If so, a simple carburetor engine with no λ feedback will tend to run a little lean. LPG as far as I know works different than gasoline. The richer the mixture, the higher the temps. Maybe your rigged LPG feed was running lean, because burnt exhaust valves (and seats) from LPG are a fact. Factory LPG systems have different valves, seats etc. For a video idea, take a stock Lada engine, maybe a 1.7 injected from a NIVA, and freshen it up so that it is in good working condition. Add a turbo and extra fuel so that the mixture is close to correct and take it to a dyno. Add boost and fuel till it goes pop and measure the results! Cheers from Greece

The combustion chamber is way way hotter but only during some parts of the thermodynamic cycle as fresh air and fuel cool it up. The reason to the meter not going up is it's mass, as it doesn't have time to get to temp between the different steps of the cycle, and that's why actual combustion temps are almost only studied in laboratories and modern cars don't have sensors there. Even with a smaller sensor it would still be nearly impossible to capture such quick changes

Messing with the ignition advance would probably show more temperature increases than just different fuel. I had 3 times valves burning up on my 1.4S carburated car due to the mechanical advance not working correctly. Only the vacuum controlled advance was working. Exhaust valve overheated and melted away on one spot. Did it on regular gas or LPG. Cooling system was ok. Changed the ignition assembly and it never burned valves again.

Look up the term 'propane enrichment'. Chrysler needed that to do a tune up properly on some models.

Answering questions that I never even knew I had. Great channel

Internal combustion engines are actually powered by pressure not heat. If you measure pressure in the cylinder, on the compression stroke you might get about 120 psi, on the power stroke the pressure in the cylinder can increase anywhere from 2 to 20 times and this increase in pressure is directly proportional to power ( more pressure, more power )

i don't know if you have done this already, but you should try running a engine upside down.

Lpg needs to be boiled in order to be expanded. Hence why lpg cars have a vaporiser or expander which is connected to the cars cooling system, the temperature from the coolant causes the gases to expand. Usually the gas would be directed into the intake via a servo actuator. I could tell you a lot more, but I'll leave this here, also lpg burns much hotter, hence why we need to use flashlube to prevent head cracks and valve damage.

Solid! Top KEK! Peace be with you.

Quality content as usual, doing all the things that other channels do not want or do not think of doing. Keep up the good work! Would love to see how higher compression / fuel injection / turbo / ethanol affect the temperatures. I can obviously guess already but how much do they affect? Maybe an idea for a future episode?

This is maybe a new video series idea. Often i think about running different motors with different working areas with some "other sort" of fuel. Not only the temperature is interesting, also the power output would be.

ALso remember, when the cylinder goes down to draw fuel, a vacuum is created. Vacuum creates cold, and cold, along with the cold fuel mixture - makes the CHT give it's cold reading.

Gotta put that onna E.F.I. Lada!!!

This was a very interesting test. I've always wondered about the temperatures. Would love to see you guys try this test on a diesel engine.

Alcohol(stoich ratio 9.8 for E85. 9.0 for E100) would reduce temperature inside the combustion chamber more significantly.

That's a dang gud cooling system for the combustion chamber to remain below 250°c

I'm glad they have English translation for Americans to watch the fun experiments

Ooooooooohhhhhh this is exciting!

Think about it... you have cool air and gas (which is atomizing and cooling the charge more) so the cumbustion chamber is getting cooled every intake stroke (and exhaust stroke) power and compression it will go up. also the head is water cooled... so it is not going to change much you'll need something faster than that EGT sensor

The gas cilinder on the passenger side. What can possible go wrong? Crazy Russians 😂😂😂

The egt sensor in the combustion chamber is loosing heat to the cylinder head and water jacket, that's why it reads lower. The gas temperature inside the combustion chamber is higher than inside the exhaust manifold The AFR for LPG was uncontrolled. The higher the revs, the leaner it became. And lean combustion = higher temperatures

And now test the different timing degrees and see how it affect the temperature in the combustion chamber❤

LPG is about 110 octane and maybe also because its burning that much slower, it let's out more heat overall during the slow combustion.

should have run the ignition timing forward and back to see how at affects both temperatures. Also should have like towed another dead lada or taken it to the testing area so they could have put an actual load on the engine

I'd like to see the same test but measuring the temperature in the catalytic convertor.

Would love to know if a sprayed in liquid form LPG injector for port injection would work better in expending heat energy during expansion into a vapor to drop intake temps even lower. Or direct injection. With tuning for timing to drop it further. The colder the combustion chamber is the better it is for power. Generally though, you can think of it this way, half the time is used intaking, the other half exhausting. Because fuel is used, that absorbs extra heat. So it should, typically, be less than half the temp of the exhaust. Kinda. Fuel timing and types can massively change temps, same for how fuel is delivered and the temp of the air coming in. If it's cooled just before or well before. Both change that as heat soak can happen.

higher octane rating = better resistance of the fuel to ignition. Logically, this means that if you dont touch the ignition advance (by the distributor cap in this case) the result will be: more fuel left to burn in the exhaust (after the exhaust valve), when used 95 octane compared to the 92 octane. This is proved when you saw that with 95 octane there was higher exhaust manifold temperature. So the test can not be qualified as accurate. The ignition advance had to be adjusted (advanced by the >correct!< degrees, not just 'some' degrees' by guess)

That thing is making a lada smoke

That was amazing

I think this needed to be tested somewhere with a long hill so the car was wide open throttle for a while, im pretty sure this would have increased the cylinder temperature quite dramatically.

hook the egt sensors readings into a computer so the temps can be charted and graphed and printed out. good video

Likely, the vaporization of the LPG is done in the tank. Therefore, they are not any change of phase occurring in the cylinder.

Interesting experiment

Gaseous fuels do no "refresh" the combustion chamber (that's why engines that burn LPG or Methan must have stronger valves and use special oil)

An interesting experiment

Did they plumb the propane directly into the bowl? 😂😂😂💀

Excellent as usual. But I am wondering if the combustion chamber egt reads low because it was surrounded by coolant.

The liquid fuel has a cooling property, when you compress fuel and turn it into a vapor it releases heat, if you compressed it enough it would explode, like diesel.... The lpg is already a vapor, so think of it like getting spritzed by a spray bottle VS getting a cup of water poured on you.

the combination will result in ReckGass

Put a snail on dat

Test again with NGK LPG Laserline spark plugs. These have reduced gaps (0.6mm). NGK claims that temps will be lowered if this spark plug used.

I love these more scientific videos!

I’d like to see these same tests on a turbocharged and naturally aspirated car

Content idea. Trailer tires vs passenger car tires. Accelerate, breaking and cornering.

AWESOME

I'd be curious on the temperature increases with an increase in compression, both in the combustion chamber and the EGT. I feel it would be a decent difference especially with higher octane fuels.

Engine block is cooled, but exhaust pipe is not. That is the difference

You should do a burnout and watch the temperature rise

You guys should look at exhaust temps running on oxy acetylene. LOL

You should test those coolant additives that claim to reduce combustion temps. Like cool down and water wetter

I wonder what the temps would be if you ran the engine on Vodka 😎

the combustion chamber is kept cooler by coolant

Your ignition timing was a bit late perhaps. Time it earlier and the combusion chamber temps will rise. Great way to fine-tune ignition timing actually.

95 octane "mid grade" wild to hear from west coast USA, lol

Consider making the Lata operate on Hydrogen (H2), in other words, run solely on water without any gasoline, make video of it. Thanks

I think the short-term future, until we get enough electricity and liquid hydrogen, Is going to be Direct cylinder injection of liquid propane The setup in the video probably evaporates the propane In the regulator. Note that propane has an extremely high ignition temperature So extremely high compression ratios can be used Mitigating the lower Energy density.

The difference in temp is a lot different because you have put senzor underneath intake valve, fresh mixture constantly cooling sensor

Cold air & gasoline lower combustion chamber temperature…btu are absorbed in the air and fuel vapor

Also the head is refrigerated and heat has more surface to dissipate

LPG has more energy per gram, that means more energy that equals more power and more heat

Please do an experiment putting propane gas under the air filter to boost power

12 seconds in, did you carpet a Lada? xD

It would be nice to check in a car with A/C (if you haven't already) whether propane (LPG) can easily replace ANY other refrigerant gas in a car air conditioner.

my egt reads 550C upon start up then stabilises at 475C at idle and 750C WOT for a pushrod v8 mild cam

You should measure the temperature inside the combustion chambers when you make pistons out of tungsten!

Would the engine tempura be lower because of the raider cooling the engine block?

Liquid fuel evaporates into a gas taking heat away from the surface it lands on, so makes things a bit cooler, LPG is already a gas by the time it reaches the cylinder, so no evaporation and therefore makes things run a bit hotter, there's also the calorific values as well to factor in, but, that's science that makes my brain hurt... :P

Is rolf engine oil any good ?

How if you add some ethanol to the gasoline?

we little devils ,have a secret habit , to move around in cauldrons on fire, on paved tar with nest made of feathers in our heads

Your chamber temp gauge isn't fast enough to show the peaks and valleys, so you're seeing an average. The exhaust manifold doesn't have the same peaks and valleys because there's no combustion to create the peaks and no cooling fuel/air stream to create the valleys. Since there's no cooling phase in the exhaust manifold your average is higher.

Unfortunately the merch store is not available from Germany :(

If the meter would be ‘faster’ and could measure the actual temperature of the gasoline burning could I guess the temperature would be higher don’t you think? It would go up and down all the time then I think.

Why not add more timing on 100 and see the effects on combustion chamber temp vs egt. You should see a significant change even with 3-4 degrees of ignition timing.

I have idea make upside down suspension in lada

It would be interesting to see what happens when you lean out the cylinder. It will obviously get hotter but how hot?

I’d love to see youse fellas make a single cylinder engine from a lada engine. Then gear it down so it can drive

Is it also because you passed the thermocouple through a coolant port?

Is Rolf any good? 🤔🤔🤔 Who has reviewed it?