Cold Weather Gains
Turbo Mini Forums

Relitively, what would gain more power in cold weather: An NA engine or a turbo.

My thinking is that a turbo will gain more, firstly because any intercooler will cool air more and because the larger volumes of air involved in charged engines means that any increase in density will have a greater effect.

And I don't want alexF spouting on that Cosworths lose power in cold air as they get too close to detonation (or something)

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

Hi,
Sounds about right to me, more moisture in the air helps too!
You can get the carb to ice quiet easily if you haven't got a heated manifold!
Cosworths don't have those kind of problems
Cheers,
Gavin :)

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I think that the power gain due to cold air will be directly proportional to the change in air density.

You can calculate it by working out the percentage decrease in absolute temperature of the air entering the cylinders.

So the increase in density from 30 down to 20 degrees C is as follows:

(273 + 30)/(273 + 20) = 1.034 i.e. 3.4% increase.

Obviously, for a turbo the temperatures are higher but the same rules apply.

This is why the intercooler makes such a big difference in power output, particular at high boost.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

Yes, you are correct.

The turbo heats it up the less and then the intercooler has less to do.

I've just ran some detailed calcs and came up with a zero increase on a turbo. I'll PM you a spreadsheet.

I think that the real gain comes from improved intercooler efficiency due to the lower ambient, but I don't know how to calculate that.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Well, I've checked my calcs.

My spreadsheet did not show any power gains because it calculates power purely from air volume flow. It does not take account of intake temperature - something to fix in the future.

However, it does show that the air temp after the intercooler has dropped from 50 deg C to 39 deg C.

This equates to a 3.4% increase in density and hence holds up the theory.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Excellent, another myth busted.

I think the general consensus was that a turbo made more gains (as I thought) but not so.

Thanks very much.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

like when you drive on foggy mornings..seems to drive a bit nicer,d ask vegard,doesnt he live in antartica?lol

Moz

I'll take BIR1 out when it's minus -20Centigrade... I might struggle with grip though..

I'm thinking about an aircon system to help the intercooler. Should have the same effect.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

axel a pal of mine with a jap import mini
was telling me about this idea also..h said it would work well,but hen there is power drain to make power,like on the pump...

Moz

something to add ,
if the mass flow through the engine rises due to the air being denser ,then the compressor map position changes ,
if the boost reference is on the inlet manifold where it should be ,so the new pos on the map may be a point of greater efficiency , so make more power ,
the turbine will need to do less work per psi and so the gate will bypass more and turbine back pressure will drop .

also moisture content in the air ,will increase cooling effect of the ic as it rises ,so colder MOISTER air will make more charge temp drop ..

also colder air is cooling the outside of the compressor housing and all the piping ducts etc more and reducing under bonnet radiant heat ,which all adds up .

also a lot of engines are dynoed with the bonnet up and so run a hotter underbonnet temp on the rd ,so the timing can be a little advanced for that situation ,the colder air brings the underbonnet temp closer to the rr temp and so the timing becomes closer to correct ...um .think thats it lol

oh no another thing ,all the positive points about water inj come into play to a certain degree with high humidity ,so smoother combustion ,effective octane increase etc etc .

oh axel there a company in the us selling an air con assisted ic ,iits on a mustang site i think .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

You notice the difference with old n/a diesels a hell of alot. upto 10mph in the transit.

regarding the intercooler efficiency, if the turbo outlet temp remains the same the inlet manifold temp will be less as the rate of cooling is increased because of the greater temperature difference across the core.
ie lower ambient = more power.
regards.
Dave

I would say if you have a turbo car with out an intercooler you would gain a more % age. other than that not sure mate as our cars as you no can't add more fuel for the cold weather, wheni drive mine this time of year it feels much slower!

Edited by Miniwilliams on 31st Oct, 2007.

Best 1/4 mile 13.2 seconds @116 mph
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There was a thread titled (heated manifold) The carb icing up was seen as a pretty bad thing. I was thinking of fitting a seperate Rad setup with a small pump and rad to the manifold to cool the air/fuel mixture as much as possible? Would this be a worth while thing. I already have all the bits lying around, cant hurt to try it out i suppose.

On 30th of Oct, 2007 at 11:00am Bat said:
Hi,
Sounds about right to me, more moisture in the air helps too!
You can get the carb to ice quiet easily if you haven't got a heated manifold!
Cosworths don't have those kind of problems
Cheers,
Gavin :)

1/4 Mile 14.3secs 96Mph Terminal 10psi of boost.


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Mike I would say in the winter months, you need some heat to be around, to stop it icing up and to help it run at a more normal temp.

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

http://www.mattwoodsphotography.com

I thought about the aircon idea, but then thought about the extra weight of pumps, Rads, coolent and the power lost through driving it all and didn't seem worth it! ;ohwell:

Iv'e been thinking of using some kind of "jacket" around the IC and pumping a liquid through it that will evaporate drawing the heat with it, and condense back into a kind of catch tank, to be pumped round again.

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1/4mile in 13.2sec @ 111 terminal on 15psi

Great idea for the summer matty, NOT for this time of year!

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

http://www.mattwoodsphotography.com

https://www.facebook.com/pages/Fusion-Fabri..._homepage_panel

www.fusionfabs.co.uk



1/4mile in 13.2sec @ 111 terminal on 15psi

Are yes there is that one to. I really should pull me finger out and take mine off the road.

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

http://www.mattwoodsphotography.com

I really should pull my finger out and get mine back on the road..pmsl

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1/4mile in 13.2sec @ 111 terminal on 15psi

lol

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

http://www.mattwoodsphotography.com