OK so if your IAT is 20-25 deg above ambient say at 75 deg, what would lowering the temp 10deg mean in power

what kind of temp drops do we see in the stock unit and how much benefit from temp drops... what kind of performance are you seeing from your IC and is a W/A that much better.... and anything else on the subject of ICs you can think of

 

This is a good question.

But I wonder can we consider lower IATs alone without considering pressure drop across the IC?

In other words, if you have a 1-2 lb. pressure drop, but IATs are slightly better, how does one offset the other?

 

If I remember right a 10º drop in IAT equates(roughly) to a 1% increase in gross HP.
Therre are a number of factors that influence this % but it's a good baseline.

 

This link provides some insight:

http://www.timskelton.com/lightning/...ntercooler.htm

About 1/2 way down, "The rule of thumb often used is 1-1.5% horsepower for every 10° reduction in intake temps."

And further down is a bonus...

 

pressure drop is important no doubt..... what are we all chasing and what are the practical benefits of this vs that?

 

I hope Dr. O chimes-in... What we are after is molecular density, where cooler is better, where more pressure is better... That said, increased pressure, all else being equal, makes more increased heat. There are trade-offs invariably such that a lower IAT can yield the same output of a higher IAT due to the increase pressure present...

 

Would lower IATs have a bigger effect on torque or on HP?

 

Now, where's my polishing cloth...?
Put this way, it doesn't look good, but I knew this all along. Lowering the approach (IAT-ambient) by 10F for any condition, let alone *all* conditions is extremely dificult if not impossible.
Now, I realize there's 2 different things here as SpiderX originally posted about the approach, but most responses have referred to the IATs.
1. There's a 10F reduction in IAT, and
2. There's a 10F reduction in approach.

If ambient is held constant, then this is the same thing, but as ambient changes throughout the daily, and yearly, cycle (not to mention global warming--- ) they mean different things.
The easiest way to reduce IATs is to wait for winter, or move north, etc. There is no easy way to reduce approach.
Also, I haven't seen anyone post numbers for a stock setup that could be combined in a meta analysis with the numbers posted for different ICs, and systems including the data I have posted. I tried to put together a meta thread, but it died...
And I aint' going backwards just to provide my own data!

 

here is where I am coming from...... I have the "Flux" from Unichip......it allows me on a PDA to monitor IAT... typically my best reading is 15 deg above the ambient temp as displayed in the Minis thermometer.... The Flux is dynamic and when I am stopped in traffic it rises as there is no air flow. With the 62 I have been thinking of the IC and different choices. The big question is how much better can I achieve and say I can get the IAT and ambient to match 1:1 what will that mean to my whp....

 

If you were to equal ambient temps or drop 15 or so degrees off of your IAT, that would seem to be worth about 3-4 hp...

 

Nice insights

Nice to know my memory is still good too

 

The ONLY time I have seen IAT and ambient match 1:1 is after the car has sat overnight and I start it in the morning before work.
With my recent shroud mod, I have seen consistent single digit differences between IAT and ambient, and as low as 4 degrees. For a street driven MINI, that's pretty good.

If you want to talk ICs, there is no aftermarket one that has less pressure drop and can recover as quickly as the stock unit. The stock IC is "light" and flows very well, and the only thing that would be better is a stock IC that flows ambient like the DFIC. I have been working on such an animal in between other projects, hopefully to get it done soon as I believe it will perform extremely well.

 

how do you feel about the GP IC

 

Honestly, I think they would have been fine with the stock unit. There isn't a whole lot of difference(if any) between the GP drivetrain and a factory JCW car(most of the GP performance is from weight reduction). They may have come up with the GP intercooler just to add to the exclusiveness and to make it look a little different under the hood. I imagine the extra rows would add some degree of cooling to the charge air, but for the price, the difficulty in obtaining one, the extra work involved just to check plugs and wires, and the fact that it is still a down draft style core, won't have me bugging my parts guy for one.

 

I think Sid (MSFITOY) has reported sub-ambient IATs due to his water-meth system, but this is the *only* situation I've heard of. Consequently an approach of 0 is --for all practical purposes-- unrealistic, and certainly not something you could achieve on a daily drive let alone a commute. (Of course, SpiderX didn't say *when* he wanted those extra 1-3 HP.)
Surely removing 50lbs of weight would be a better way to achieve performance gains. (Can anyone even feel +-3HP on a 200HP, 2600lb car?)

 

I believe, as calculations would have it, that too (50 lb loss) would equate to about 3 hp... not to mention other benefits as well... Every little bit helps!

 

I think that is my point.... we (I) stress over changes that at best get 3 whp

 

...and I'm there with you. But every now and then I feel an obligation to bring the perspective back in. My posts more often than not reflect my own conflicts and doubts--and I need the perspective maybe even more than anyone else.

But I'm over it now

 

What do you guys think about the use of a nitrous spray bar over the intercooler? I think it has been discussed before, but I couldn't seen to find it anywhere. This would bring IAT temps down dramatically.

Being that I live in AZ, anyway to cool IAT's down during the summer is money well spent for me!

 

I don't know that I would go through all that just to spray it on the outside of the engine. Rig that stuff to go on the inside, man!

Seriously, I would try a cool can in the fuel line before I sprayed the IC with nitrous.

 

Hmm, I've heard its relatively simple to set up. I'd rather not install a full blown nitrous system for the engine, just not something that I've ever really been into or think is a good idea.

Nitrous on the intercooler, using a spray bar, seems like a easy way to lower IAT's far below ambient to reclaim lost hp, and pick up a decent amount of ponies. Plus, its always removable if its causing problems or I want to sell the car. A nitrous system seems a little more permanent than that.

 

If I drag raced the car this would be an option but I am thinking more twisties and daily fun...... more of a set and forget permenant solution with no maintenance.... well maybe W/A

 

I love to read the thoughts of a thinking man...... a "Mini philosopher"....

I remember spending some pretty stupid money ($1000) in hopes of gaining 5 whp...... I won't do that again.

I have a DFIC and this is not a promotion for M7 but I think it does a good job...... I have plenty of pressure so pressure drop is not a huge concern but I would like to have as little as possible...while maintaining good cooling of course. There are guys out there making 230+ with a M45 and a DFIC. In the last few weeks as I move on to Jan's head I was evaluating some parts including DFIC and my conclusion is that so far the differences are not worth the cost....

There was a very nice looking W/A at the Dragon using technology from Sweden that looked very interesting but I can not find the vendor (help if you know who he is).... but again I say that unless the performance gain starts to climb above say 7-8whp and similar tq.... I am not too motivated.

The purpose of me starting this thread is to try to get some knowledge and participate in my favorite hobby which is "stamping out my own ignorance"

So some empirical data or maybe just theory backed up by hear say and wild *** guesses are all welcome..... let's kick this thing around some.

 

What about a GRS charge cooler?

http://www.grsmotorsport.co.uk/minichargecooler.html

 

OK, some more kicking around, in the form of a taxonomy of options:

1. Low budget stock +
Here I'm thinking what can be done with a stock or close to stock setup with modest money? My experience suggests a CAI, with insulated airbox, an Alta diverter mated to a nice big scoop either symetrical or offset. I bet this gets most of the drop in approach that's possible.
2. Bigger budget not stock
(This is me, I guess) A new IC, experiment with intakes (what ever happened to Dr O's HAI mod?) and start hacking up your engine bay. I'd say this gives most of the drop in approach possible short of the next step.
3. Highly modified
Here we're talking water-meth injection to cool the charge. There's no doubt it works but how often are you at +12psi? Spraying water or nitrous on the outside of the IC has very little affect, especially if not done on a continuous basis.

btw, I need to share one recent observation (done before the IMD mod). I removed the Alta box top and went back to sealing the box against the bonnet liner which I still run. Airbox temps are consistently 2-3F lower even though that's not enough to reject the null hypothesis that I'm dreaming all this. My hypothesis is that once the airbox top get hot since it's metal, it stays hot and warms up the airbox.