The truth about upgrades...

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Lankan
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andybond wrote: Fri Jul 17, 2020 1:52 pm From my research there are a couple of reasons for heat soak.

1 ) Location of the actual air to air intercooler. Its directly above the block which has limited airflow so naturally the heat rises and dissipates some of its energy into the A/A intercooler
2 ) The supercharger is running towards the upper limits of the design for the MP62 anyway so generates a lot of heat for the A/A intercooler to dissipate, but
3) The actual mohawk or even the smaller air ducts on the top of the roof are not very efficient due to size and location. The radiator exhausts are releasing warm air into the intake tract for the intercooler hence not cooling as well as it could.

There are some solutions
1 ) A better core with some cooling ducts as seen with the pro alloy kit
2 ) Chargecooling.

You will note the shortcomings when pressing on and then stopping in traffic and sustained WOT on tracks. For general road use I would wager that you will find it hard to notice any degredation. This is more due to the fact that its a gradual change rather than a somewhat digital change..
Thank you Andy. That was very helpful.

I did suspect that the longer roof scoop may suck up the hot air 'better' than the shorter scoop.

Oh, well....more things to investigate, but now I really need #138 in my possession, and to drive it, before thinking any further.

This is probably the only time in my car-owning history that I know more about a car than how it actually drives! :o
2010 Exige S RGB #138
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Fonzey
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Some echoing going on in here :lol:
Lankan
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Oh well, couldn't just twiddle my thumbs without digging into this a bit further....so, kept looking....and...

...then I came across this post on Lotus Talk titled '2007 Exige S Intercooler Air Flow Study'.
https://www.lotustalk.com/threads/2007- ... udy.59117/

It appears that the different length roof scoops are not the limiting factor, but...
"It seems that the inlet is not the limiting factor. Most of us have suspected the bottleneck where the end of the roof and the beginning of the clam meet is the limiting factor...".

Image

If the intercooler is fed air from that narrow slot (as shown above) then I am not surprised that the volume of air may not be enough to enable the intercooler to do its job efficiently, and that is made worse if the air that is fed in through that slot comes off the front radiators and is at a much higher temperature.

Does anybody disagree with this?

Page 2 of the above thread is quite interesting - apparently one needs to Dremel away the 'limiting factor' shown above. 8-)

Next, question; has anybody done this surgery, and found this solution to produce a satisfactory result?
2010 Exige S RGB #138
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andybond
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I don’t disagree with it , but I feel your fighting a losing battle

Best call Jon now and ask for the chargecooler to be fitted before collecting..
Lankan
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andybond wrote: Fri Jul 17, 2020 9:53 pm I don’t disagree with it , but I feel your fighting a losing battle

Best call Jon now and ask for the chargecooler to be fitted before collecting..
Great. This is all good info for now.

Understanding the shortcomings is the first step....I will get on to fixing them depending on how I far they affect, or get in the way, of enjoying #138.
2010 Exige S RGB #138
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andybond
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If you aren’t tracking , I don’t think you will notice TBH.
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Fonzey
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I did the "letterbox" mod on mine when I was chasing temps last year, it worked but it was probably the least significant single addition compared to the side ducts. It's all about incremental improvements though and it's a zero cost solution to help things.
winthattt
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The narrow slot may be a problem but it’s not obviously the case. As the air goes through the slot into the larger nozzle to the heat exchanger it will slow down. The slow flow of air MAY be just right to flow through the heat exchanger matrix without being turbulent which will improve the thermal efficiency of the exchanger. To be sure it would need an expert and cfd modeller. On the other hand, I expect Lotus just designed it to look ok with the car so the aerodynamics are whatever came out of the stylist’s pen and they are unlikely to be optimised.

.... and yes.... hot air from the radiators is not a great idea but it may not be that bad, heat transfer rate is influence by the temperature differences and a load of other factors.

On balance, I’d say it’s more than likely that opening the narrow slot will help matters.
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