Supercharger with no Intercooler or Charge cooler
Discussion
Just a qucik question.
I know Exige S are vulnerable to a bit of heat soak on a hot day.
I imagine without an intercooler the charge temps would be even higher ?
Or is it the case the case that without an intercooler the colder air from outside the engine bay goes straight into the Supercahrger and doesn't have a chance to heat up ?
Can someone clarify ?
Thanks
Ex77
I know Exige S are vulnerable to a bit of heat soak on a hot day.
I imagine without an intercooler the charge temps would be even higher ?
Or is it the case the case that without an intercooler the colder air from outside the engine bay goes straight into the Supercahrger and doesn't have a chance to heat up ?
Can someone clarify ?
Thanks
Ex77
any form of compression will create heat. Think of the bicycle pump getting hot when you pump the tyre up. The reason for an intercooler is not just to remove heat from heatsoak. Methanol injection cools the air too , without the need of an intercooler. See the JSD converted rotrex cars.
your not understanding this are you?
No inter-cooler will always end up with hotter charge temps and one with an inter-cooler.
this makes NO DIFFERENCE to the air INTO the charger, the inter-cooler is /after/ the supercharger.
heat soak is actually the wrong term to use here, the problem is that the std inter-cooler is just crap, as in it can't shed the heat as fast as the supercharger can add it, that said, /anything/ is better than nothing.
No inter-cooler will always end up with hotter charge temps and one with an inter-cooler.
this makes NO DIFFERENCE to the air INTO the charger, the inter-cooler is /after/ the supercharger.
heat soak is actually the wrong term to use here, the problem is that the std inter-cooler is just crap, as in it can't shed the heat as fast as the supercharger can add it, that said, /anything/ is better than nothing.
A 'Charge Cooler' and 'Inter Cooler' are two different things and two different methods of cooling a hot compressed gas, in this case, air that is being forced (forced induction) into an engine via or through its induction system (inlet manifod).
To give a good example of this, take a look at the 2 Stage, 2 Speed Rolls Royce Merlin 66 (or Packard 266) engines used in the Spitfire during WWII. This engine, infact uses both !
This engine has 2 separate air compressors (superchargers) that work in unison to force the incoming air into the engine ...the 2 Speed side of things I shall leave alone for the moment as this may confuse matters and is only applicable when an aircraft is at higher altitudes.
This is how it basically works... air leaves the carburettor and is drawn into the 1st Stage compressor where it naturally heats up (approx. 150 deg C), the hot air then goes into the 2nd Stage compressor. However, INBETWEEN the 1st & 2nd Stages the air is cooled by water circulating in a water jacket... this is called the 'INTER Cooler'. This air then leaves the 2nd Stage compressor and as it no longer needs to be compressed any further, it is called the air 'Charge'. However, this air is now so hot (approx. 350deg C) that it cannot enter the engine without causing severe problems (detonation etc.). Therefore, this air needs to be finally cooled to acceptable levels (approx. 200deg C), so it is passed through a heat exchanger (radiator)... this is called the 'CHARGE Cooler'. The air then passes into the engine for combustion without any prblems.
For the 2 speed side of things, basically, the higher the altitute an aircraft flies the less air (oxygen) is available for combustion. In this case, more air needs to be compressed. To do this the 1st & 2nd Stage compressors need to rotate faster. This is accheived by using a series of clutches and a gearbox attached to the compressor... ineffect the compressors change gear, at a preset altitude.
Hope the above explains...
To give a good example of this, take a look at the 2 Stage, 2 Speed Rolls Royce Merlin 66 (or Packard 266) engines used in the Spitfire during WWII. This engine, infact uses both !
This engine has 2 separate air compressors (superchargers) that work in unison to force the incoming air into the engine ...the 2 Speed side of things I shall leave alone for the moment as this may confuse matters and is only applicable when an aircraft is at higher altitudes.
This is how it basically works... air leaves the carburettor and is drawn into the 1st Stage compressor where it naturally heats up (approx. 150 deg C), the hot air then goes into the 2nd Stage compressor. However, INBETWEEN the 1st & 2nd Stages the air is cooled by water circulating in a water jacket... this is called the 'INTER Cooler'. This air then leaves the 2nd Stage compressor and as it no longer needs to be compressed any further, it is called the air 'Charge'. However, this air is now so hot (approx. 350deg C) that it cannot enter the engine without causing severe problems (detonation etc.). Therefore, this air needs to be finally cooled to acceptable levels (approx. 200deg C), so it is passed through a heat exchanger (radiator)... this is called the 'CHARGE Cooler'. The air then passes into the engine for combustion without any prblems.
For the 2 speed side of things, basically, the higher the altitute an aircraft flies the less air (oxygen) is available for combustion. In this case, more air needs to be compressed. To do this the 1st & 2nd Stage compressors need to rotate faster. This is accheived by using a series of clutches and a gearbox attached to the compressor... ineffect the compressors change gear, at a preset altitude.
Hope the above explains...
context or not, he is essentially correct.
back to Loti, the charge cooled esprit was where it had carbs and the air/fuel 'charge' when though the cooler, hence the term 'charge cooled'
Inter-cooler by definition is where the cooling is between stages, makes no odds if it's air/air, water/air, etc.
back to Loti, the charge cooled esprit was where it had carbs and the air/fuel 'charge' when though the cooler, hence the term 'charge cooled'
Inter-cooler by definition is where the cooling is between stages, makes no odds if it's air/air, water/air, etc.
Scuffers said:
your not understanding this are you?
No inter-cooler will always end up with hotter charge temps and one with an inter-cooler.
this makes NO DIFFERENCE to the air INTO the charger, the inter-cooler is /after/ the supercharger.
heat soak is actually the wrong term to use here, the problem is that the std inter-cooler is just crap, as in it can't shed the heat as fast as the supercharger can add it, that said, /anything/ is better than nothing.
This is quite interestingNo inter-cooler will always end up with hotter charge temps and one with an inter-cooler.
this makes NO DIFFERENCE to the air INTO the charger, the inter-cooler is /after/ the supercharger.
heat soak is actually the wrong term to use here, the problem is that the std inter-cooler is just crap, as in it can't shed the heat as fast as the supercharger can add it, that said, /anything/ is better than nothing.
The Elise S/C has no intercooler so i assume suffers no heatsoak?
The basic Exige has the same hp output (more or less) and a intercooler, yet i've read on these and other forums that on hot days the car loose's power, due to heatsoak
Yet i've not seen any mention of S/C loosing power on hot days?
So i guess my question is, does the S/C suffer the same issue's as the Intercooled 218hp Exige? or worse, as there is no intercooler at all?
peter450 said:
Scuffers said:
your not understanding this are you?
No inter-cooler will always end up with hotter charge temps and one with an inter-cooler.
this makes NO DIFFERENCE to the air INTO the charger, the inter-cooler is /after/ the supercharger.
heat soak is actually the wrong term to use here, the problem is that the std inter-cooler is just crap, as in it can't shed the heat as fast as the supercharger can add it, that said, /anything/ is better than nothing.
This is quite interestingNo inter-cooler will always end up with hotter charge temps and one with an inter-cooler.
this makes NO DIFFERENCE to the air INTO the charger, the inter-cooler is /after/ the supercharger.
heat soak is actually the wrong term to use here, the problem is that the std inter-cooler is just crap, as in it can't shed the heat as fast as the supercharger can add it, that said, /anything/ is better than nothing.
The Elise S/C has no intercooler so i assume suffers no heatsoak?
The basic Exige has the same hp output (more or less) and a intercooler, yet i've read on these and other forums that on hot days the car loose's power, due to heatsoak
Yet i've not seen any mention of S/C loosing power on hot days?
So i guess my question is, does the S/C suffer the same issue's as the Intercooled 218hp Exige? or worse, as there is no intercooler at all?
with no cooler, the AIT's are going to be whatever the charger put's air out at, and to a large extent, this is (relatively) predictable, the only real variable is how hot the charger itself get's (when it's cold it absorbs some of the heat from the air being pumped, once it;s hot, its no longer is doing this - to a point, this is heat soak)
now, assuming the setup is such that it can run OK at the AIT's the charger is outputting, then no problem, and although the charger etc will heat up the AIT's will not be wildly different.
now, if you add an intercooler to this setup and don;t change anything else, then the cooler will lower the AIT's, but unless the ECU then advances the spark to take advantage of this, the only extra power you will make is in lower parasitic looses to the charger (as cooling the air increases the air density, thus lowering it's pressure, thus needing less 'pushing' from the charger)
now, Lotus have decided that at 220Bhp they don't need cooling, but at 240 they do, however, if the cooler is not very effective, then as soon as it's ability to cool the air is reduced to the point where the engine can;t deal with it, the ECU will have to back off the spark etc to avoid detonation, thus loosing power.
this is why adding a decent cooler to an Exige makes such a difference in power, it's not that you get More per say (although you will in lower parasitics), it;s that you can run at this power without the ECU having to pull it back with heat.
Scuffers said:
back to Loti, the charge cooled esprit was where it had carbs and the air/fuel 'charge' when though the cooler, hence the term 'charge cooled'
I'm going to wave my pedantic flag around for this one, Simon. The chargecooled Esprit first appeared in 1989 and was running a sophisticated (for the era) fuel injection system. The compressed air passed from the turbo and through the chargecooler in effort to remove some of the resultant heat and then onto the plenum chamber, where it was distributed to each cylinder. Once this compressed air was inside the combustion chamber, the injectors added the fuel. I'm ignoring the extra pair of plenum mounted WOT injectors for now, simply to make the point that only air passes throught the chargecooler and not a fuel/air mix.
No carb fed Esprits were fitted with chargecoolers from the factory.
I did warn you I was being pedantic.
GKP said:
Scuffers said:
back to Loti, the charge cooled esprit was where it had carbs and the air/fuel 'charge' when though the cooler, hence the term 'charge cooled'
I'm going to wave my pedantic flag around for this one, Simon. The chargecooled Esprit first appeared in 1989 and was running a sophisticated (for the era) fuel injection system. The compressed air passed from the turbo and through the chargecooler in effort to remove some of the resultant heat and then onto the plenum chamber, where it was distributed to each cylinder. Once this compressed air was inside the combustion chamber, the injectors added the fuel. I'm ignoring the extra pair of plenum mounted WOT injectors for now, simply to make the point that only air passes throught the chargecooler and not a fuel/air mix.
No carb fed Esprits were fitted with chargecoolers from the factory.
I did warn you I was being pedantic.
not really up on Esprit's, but I have seen one with carbs and intercooler, so I guess it was non-std for or something??
This is wikipedia's definition:
An intercooler (original UK term, sometimes aftercooler in US practice), or charge air cooler, is an air-to-air or air-to-liquid heat exchange device used on turbocharged and supercharged (forced induction) internal combustion engines to improve their volumetric efficiency by increasing intake air charge density through nearly isobaric (constant pressure) cooling. A decrease in air intake temperature provides a more dense intake charge to the engine and allows more air and fuel to be combusted per engine cycle, increasing the output of the engine. Intercoolers increase the efficiency of the induction system by reducing induction air heat created by the turbocharger and promoting more thorough combustion
The inter prefix in the device name originates from historic compressor designs. In the past, aircraft engines were built with charge air coolers that were installed between multiple stages of supercharging, thus the designation of inter. Modern automobile designs are technically designated aftercoolers because of their placement at the end of supercharging chain. This term is now considered archaic in modern automobile terminology since most forced induction vehicles have single-stage superchargers or turbochargers. In a vehicle fitted with two-stage turbocharging, it is possible to have both an intercooler (between the two turbocharger units) and an aftercooler (between the second-stage turbo and the engine). The JCB Dieselmax land speed record-holding car is an example of such a system. In general, an intercooler or aftercooler is said to be a charge air cooler.
Intercoolers can vary dramatically in size, shape and design, depending on the performance and space requirements of the entire supercharger system. Common spatial designs are front mounted intercoolers (FMIC), top mounted intercoolers (TMIC) and hybrid mount intercoolers (HMIC). Each type can be cooled with an air-to-air system, air-to-liquid system, or a combination of both.
Cheers Greg.
An intercooler (original UK term, sometimes aftercooler in US practice), or charge air cooler, is an air-to-air or air-to-liquid heat exchange device used on turbocharged and supercharged (forced induction) internal combustion engines to improve their volumetric efficiency by increasing intake air charge density through nearly isobaric (constant pressure) cooling. A decrease in air intake temperature provides a more dense intake charge to the engine and allows more air and fuel to be combusted per engine cycle, increasing the output of the engine. Intercoolers increase the efficiency of the induction system by reducing induction air heat created by the turbocharger and promoting more thorough combustion
The inter prefix in the device name originates from historic compressor designs. In the past, aircraft engines were built with charge air coolers that were installed between multiple stages of supercharging, thus the designation of inter. Modern automobile designs are technically designated aftercoolers because of their placement at the end of supercharging chain. This term is now considered archaic in modern automobile terminology since most forced induction vehicles have single-stage superchargers or turbochargers. In a vehicle fitted with two-stage turbocharging, it is possible to have both an intercooler (between the two turbocharger units) and an aftercooler (between the second-stage turbo and the engine). The JCB Dieselmax land speed record-holding car is an example of such a system. In general, an intercooler or aftercooler is said to be a charge air cooler.
Intercoolers can vary dramatically in size, shape and design, depending on the performance and space requirements of the entire supercharger system. Common spatial designs are front mounted intercoolers (FMIC), top mounted intercoolers (TMIC) and hybrid mount intercoolers (HMIC). Each type can be cooled with an air-to-air system, air-to-liquid system, or a combination of both.
Cheers Greg.
I agree, it does seem like people are swapping terms here and using prefixs of inter- and charge- for air-air, air-liquid.
What are the options for replacing the lotus ones found in the exiges (like the one from Pro-Alloy?)and are these replacements air-air, air-liquid.
I seem to remember the cup car I had, had a bigger intercooler than the 220 car.
What are the options for replacing the lotus ones found in the exiges (like the one from Pro-Alloy?)and are these replacements air-air, air-liquid.
I seem to remember the cup car I had, had a bigger intercooler than the 220 car.
Mr Fix It said:
I agree, it does seem like people are swapping terms here and using prefixs of inter- and charge- for air-air, air-liquid.
What are the options for replacing the lotus ones found in the exiges (like the one from Pro-Alloy?)and are these replacements air-air, air-liquid.
I seem to remember the cup car I had, had a bigger intercooler than the 220 car.
Lotus do/did two sizes of air to air coolers, I guess the bigger one too more time to be defeated by heat...What are the options for replacing the lotus ones found in the exiges (like the one from Pro-Alloy?)and are these replacements air-air, air-liquid.
I seem to remember the cup car I had, had a bigger intercooler than the 220 car.
the Pro-Alloy kit is Air/Water/Air, and if installed right, is about as good as your going to get thermally.
hmmmmm 
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