2007 Exige S Intercooler Air Flow Study

[EricH]

Smoky & apk919

[charliex]

I found the ic does heat up quickly at idle, but then it cools down fast once you're driving and on load is when it actually makes a difference.

can you plot rpm/load along with the data too?

For the life of me i can't find my datalog from LA to LV, i'll have to make another one!

[apk919]

Originally Posted by charliex

I found the ic does heat up quickly at idle, but then it cools down fast once you're driving and on load is when it actually makes a difference.

can you plot rpm/load along with the data too?

For the life of me i can't find my datalog from LA to LV, i'll have to make another one!

I have Mag's latest data too... I haven't gone through it yet, but that's a graph I'd like to see (and will post if it's feasible).

Charlie, what are the best options for data logging? The Innovate system that Mag is using looks pretty nice; what are you using?

[ocelot27]

I'm going ahead with my plan to ditch the duct on the forward side of the the IC and install the biggest fans that will fit in its place - whatever minimal air does go through the duct will still get to the IC if the fans are on. Massive airflow is the solution and sucking air through the duct with fans is not going to give massive air flow. The duct is the bottle neck - I would bet that disconnecting the duct system entirely and just using big fans will level things out nicely; I also think this will work better than an air/water IC - same soak issue with this solution only it just takes longer to saturate the systems water volume with heat - better just to blow the heat right the hell out of the engine bay with big fans.

-john.

[Illumiloti]

Originally Posted by ocelot27

I also think this will work better than an air/water IC - same soak issue with this solution only it just takes longer to saturate the systems water volume with heat - better just to blow the heat right the hell out of the engine bay with big fans.

-john.

Assuming the water to air has a sufficient heat exchanger and pump, why would this happen? The engine water temps are kept at a constant level with a properly functioning system, why wouldn't the same apply to a water/ air intercooler utilizing the same principles?

[charliex]

i'm reading the tmap and tmaf directly through the ecu so i can see the temps.

[apk919]

Originally Posted by charliex

i'm reading the tmap and tmaf directly through the ecu so i can see the temps.

Aha! So the tmap's temperature is being read by the ecu, just not used in the factory tune? Is there any way to get to the tmap's values through the bus?

[charliex]

they're hooked up but it splits the function between the two, so temp on one, airflow on the other.

unfortunately lotus disabled the can bus diagnostics on the later firmwares, so you're out of luck, i'm not sure if its exposed on the obd ii oem mode or not.

[robains]

Maybe we need to ask Casey at FF how he got 85F for intake air on their 380 turbo car?

I still think the location of the IC is horrible and the primary cause of it's lack of efficiency. Has anyone thought about moving it forward and up a little and then isolating the engine area using the side ducts to flow are into the engine bay?

I would think trimming the plastic duct a little and removing some of that angle while raising the IC higher -- could probably gain 3-4" up and back. Isolate the engine bay with 3 pieces of aluminum (CF if it actually works) that can be easily removed/installed with rubber gromets around the necessary IC tubing. It might require some new IC tubing that is slightly longer (not much) -- but keeping the tube length short is a BIG plus.

Think I might take some measurements and pics.

[apk919]

Originally Posted by charliex

they're hooked up but it splits the function between the two, so temp on one, airflow on the other.

unfortunately lotus disabled the can bus diagnostics on the later firmwares, so you're out of luck, i'm not sure if its exposed on the obd ii oem mode or not.

It seems as though the only temps exposed in OBD-II OEM mode are IAT (which I think is taken from the TMAF, not the TMAP), and engine coolant temperature. At this point I'm not up to hacking into the ecu...

[charliex]

OEM mode is the secret manufacturer specific one, not the standard IAT PID.

i'll take a look when i get 5 minutes.

[apk919]

Originally Posted by charliex

OEM mode is the secret manufacturer specific one, not the standard IAT PID.

Oops, I meant Global OBD mode... (at least that's what it's called on my reader). The reader has specific code for most OEM's, but of course not Lotus.

Originally Posted by charliex

i'll take a look when i get 5 minutes.

Cool, thanks.

[ocelot27]

Originally Posted by Pestodude

Assuming the water to air has a sufficient heat exchanger and pump, why would this happen? The engine water temps are kept at a constant level with a properly functioning system, why wouldn't the same apply to a water/ air intercooler utilizing the same principles?

Every time you transfer heat from one medium to another you loose efficiency. Going from air to aluminum to water to aluminum to air is much less efficient than going from air to aluminum to air... if the air your using for cooling is about the same temp. So, ultimately, it is the mass air flow over the heat exchanger and the temperature difference that determines how much heat can be removed - regardless of which method you use.

You're right, if you have a big enough heat exchanger and... big fans... and lots of water flow you could get great cooling with the added benefit of much greater thermal capacity in the large volume of water. Thermodynamically in our scenario its better to cut out the middle man and just do two transfers - especially considering that the air used to cool the IC is roughly the same temp as the air used to cool the water in a water cooled IC. The only reason the water systems work better is that they remove the heat from the whole system by using a large well-cooled heat exchanger - we already have a good heat exchanger - it's just not well-cooled.

-john.

[Mag]

Originally Posted by Smoky

Obviously the charge cooler is "the" solution to lower temps.

Unfortunately the current chargecooler offering is way too expensive and way to difficult for the average enthusiast to install. And since not everyone lives down the road from a top-notch Lotus aftermarket specialist, it is just plain out of reach for the majority. I've even read a few complaints that the chargecooler isn't doing that great a job either, as well as complaints that the chargecooler radiator prevents the primary radiator from receiving the cooling air it needs to do the job of releasing heat from the coolant.

If someone would introduce a production (ie. not "one-off") chargecooler system that was completely contained and installed in the engine bay, THEN we'd really have something.

Until such a product arrives, just saying "use a chargecooler" is a cop-out. I'm much more interested in this research towards air-to-air cooling. We're not saying air-to-air will ever produce BETTER results than water cooling, but the search for the most OPTIMIZED air-to-air cooling is what we're after. It is obvious the OEM solution is not optimized. That's the goal, IMHO.

yes i think air to air is the way to go for a street car... but we need air. the gt3 race cars are water systems but who knows how they set up the 2 seperate water systems cooling upfront (or on sides even). Not something I think we can replicate. Even if it could be replicated, as smokey commented, the two systems would be completely different animals in terms of cost, vehicle configuration ... etc etc. Change one thing, it'll affect another and the horsesies on the merry go round and round....

If one were to spend the money on a truelly viable water charge cooler, why not just invest in a new clam/hatch/roof set up instead. That would be simpler. Take Orange's set up for example, where he modified the roof scoop. do the same with the clam structure and we might have something. (birds in the IC for one as commented by mr. orange )

I was also concerned about blocking the radiator. Which again addresses the issue, what is the correlation contribution of ECT versus IAT to performance.

If everything was in the engine bay, we'd be back at the same problems we are facing now, accept charges might be "better" off in low speed situations.

[Mag]

Originally Posted by Pestodude

Assuming the water to air has a sufficient heat exchanger and pump, why would this happen? The engine water temps are kept at a constant level with a properly functioning system, why wouldn't the same apply to a water/ air intercooler utilizing the same principles?

"the water to air has a sufficient heat exchanger and pump"

Water transfers heat better:
Here, water has a sizeable advantage—its specific heat capacity of 4.184 J/gK is more than four times higher than air's 1.005 J/gK. Water looks even better when we consider thermal conductivity, which describes a material's ability to conduct heat. Thermal conductivity is measured in watts per meter Kelvin, and again, higher values are better. Water's 0.6062 W/mK thermal conductivity dwarfs that of air, whose thermal conductivity is only 0.0262 W/mK.


THat said:
I think ultimately using water2air exhanges the volume of air that passes the an air2air system with a fixed volume of water. On a normal air to air with access to flow, the ambient temp air is limitless. In a water system, it's recycled and it would take a lot of water to replicate the same consistent ambient temp'd water. How to get rid of that transfered heat?

On an engine coolant system, the ambients are far lower than target water temps so this might be one reason this kind of system works well.

[qball]

I ran some tests with thermocouples inserted underneath the rubber coupler directly into the airflow before and after the IC.

I never saw temperatures where the exit temps were more than the inlet temps

I'll try and redo some data tables

[ocelot27]

Originally Posted by Mag

"the water to air has a sufficient heat exchanger and pump"

Water transfers heat better:
Here, water has a sizeable advantage—its specific heat capacity of 4.184 J/gK is more than four times higher than air's 1.005 J/gK. Water looks even better when we consider thermal conductivity, which describes a material's ability to conduct heat. Thermal conductivity is measured in watts per meter Kelvin, and again, higher values are better. Water's 0.6062 W/mK thermal conductivity dwarfs that of air, whose thermal conductivity is only 0.0262 W/mK.


THat said:
I think ultimately using water2air exhanges the volume of air that passes the an air2air system with a fixed volume of water. On a normal air to air with access to flow, the ambient temp air is limitless. In a water system, it's recycled and it would take a lot of water to replicate the same consistent ambient temp'd water. How to get rid of that transfered heat?

On an engine coolant system, the ambients are far lower than target water temps so this might be one reason this kind of system works well.

Exactly - you still have to get rid if the heat using air so why not just use air to start with and eliminate the inefficiencies of multiple heat transfers; you may need lots of air, however (we need to know how much).

If we had the specific heat transfer specs of the IC's in use we could calculate everything and do some "real" engineering... or, ultimately, through trial and error the best and easiest improvement will be determined.

I think by either modifying the existing duct system (expensive, more complicated to fab and less effective in a nonmoving car) or by adding some big-ass fans (cheap, less complicated to implement and works regardless of speed) will definitely show improvement in IATs - how much and how significant in terms of gained HP is another issue. It would be cool to use the temps from the right location (the TMAP) and have Charlie, if possible, write the ECU using this sensor and maybe get a whole different dynamic out of the tune?

This is all very exciting and I'm eager to se what different people come up with.

-john.

[Mag]

guys... think i jumped the gun on this. This lotus is kind of like my own personal home study project. My other cars are under the care of a tuner. Asked him about the readings showed him the graph. To which he replied: the way my therocouples are set up now, it's taking the temperature of the pipe itself. this is for both pre/post IC. So it makes sense post is hotter as it's closer to the SC in terms of materials between.

I need to make a gasket out of Bakelite for the sensors between the pipe and the copper fixture for the thermocouple probe.

[Mag]

Originally Posted by charliex

OEM mode is the secret manufacturer specific one, not the standard IAT PID.

i'll take a look when i get 5 minutes.

charlie... May I ask: does that mean the OEM mode is reading for the intake charge pre-intake manifold via TMAP temp sensor? If not is there another sensor we dont know about... or is the ECU using an offseting formula to get the IC outlet charge temp? - thanks

[apk919]

Originally Posted by Mag

guys... think i jumped the gun on this. This lotus is kind of like my own personal home study project. My other cars are under the care of a tuner. Asked him about the readings showed him the graph. To which he replied: the way my therocouples are set up now, it's taking the temperature of the pipe itself. this is for both pre/post IC. So it makes sense post is hotter as it's closer to the SC in terms of materials between.

I need to make a gasket out of Bakelite for the sensors between the pipe and the copper fixture for the thermocouple probe.

OK, that makes sense to me... I was a bit suspicious of that...