Thanks - I just started working on my Master's degree in Applied Physics, so I'm "knocking the rust off" of a lot of the things I learned in my undergraduate math, physics, and engineering courses.

I'd love to find a way to do my Master's thesis on something MINI-related, but that might be a tough sell for my advisor.

On the other hand, the school I'm going to (Naval Postgraduate School) has this wicked electromagnetic railgun that I'm itching to get my hands on, so I think I might end up doing my thesis on some aspect of that project. I don't think it would be applicable to the MINI, though, because the power supplies weigh more than my car does!

 

Thanks - I understood your compliment and took it as you intended it. I was just a little apologetic because I've always felt that the better you understand something, the more simply you can explain it. Since there were parts of my post that I thought were still a little dense/awkward/wordy/technical, that's a sign to me that my understanding isn't perfect.

Still, I'm glad it was helpful.

 

Scott-Great post and explanation. You are right, when you understand something you can explain it better, hence make it easier for others to know what your talking about.

Although, I have a question. You mentioned in your theory that,, n,, was mass of gass but later when describing the interactions of P, V and T you noted "n" in parenthesis to be mass of air instead of gass!! like so,, n (mass of air) ? Just something I noticed. Is that correct or was it something I missed?

 

Sorry, I used "gas" interchangeably with "air". I was using the scientific meaning of "gas" (as in "solid", "liquid" and "gas"), rather than as an abbreviation for "gasoline".

Anywhere in my post that you see "gas", I was talking about the air traveling through the engine. Whenever I was referring to gasoline, I used "fuel".

 

I just realized I never answered the second part of your question (loss of efficiency at extremely-low boost levels).

Yes, there is a point of diminishing returns on the low end as well. If you were to fit a way-oversized supercharger pulley in order to slow down the supercharger and hold boost down to 1 psig, for example, and just rely on cooling the air to get your horsepower gains, than the parasitic drag and flow resistance from the supercharger would probably offset any power gains you'd get from the 1 psig of boost. At that point, you'd be better off just removing the supercharger altogether and fitting some kind of ram-air setup.

At this point, you could remove the intercooler as well, because without the supercharger heating up the air, there's nothing for the intercooler to do. The air flowing *into* the intercooler wouldn't be any warmer than the air flowing *around* the intercooler, so there wouldn't be any heat exhange taking place, and the intercooler wouldn't cool off the air going into the engine.

 

Thank you Scott, all of this seems clear after I read it three times. My car does feel faster for both the driver and passenger but I'm still sad :-( to see my boost gauge only hit 14 to 15psi when yesterday with the same core intercooler it was hitting 17psi. I guess it is human nature and being a guy to want to have the needle peg to the "RED" I wonder if I should put my stock intercooler back on just to see if I get 17psi again. I will also call Mini Madness to check on the "loss of boost". They have sold many of these kits and should have some sort of answer.
Thank you again for the education.
Mario

 

LOL - that's *completely* understandable. For a lot of people, "boost" equals "power", and it can be a little disconcerting when drastically improving the efficiency in another part of the system can increase power, but leave you with lower boost readings.

There are plenty of musclecar guys that have upgraded from a 6-71 blower to an 8-71 (or God help them, a 10-71 or 14-71), and been disappointed that they're getting lower boost readings, even though they've picked up 300 more horsepower and can't keep the tires stuck to the pavement!

Part of what seems to be bothering you is the fact that the MM intercooler is the "same" as the stock intercooler, so you're expecting similar boost numbers. It's not really the same, though, because whereas the stock intercooler relies on thin, hot, engine-bay air to pull heat out of the intake air, the MM setup uses dense, cooler water to serve the same function. Cool water can absorb a lot, LOT, *LOT* more heat than warm air, so you've increased the efficiency of the intercooler core by an unbelievable amount. It's the same reason that packing ice around a stock intercooler, or spraying it with water or alcohol, will improve performance, even though the intercooler itself hasn't changed.

 

I can just read Mario's mind now, thinking, how can I get that lost 3 psi back? lol

 

We need some annual NAM awards - Scott's second one would get my vote for post of the year. Outstanding. Really.

By the way - gentlemen, I think we have our candidate for building our MINI flux capacitors. Keep up the studies, Scott, and play around with that railgun. I'm countin' on you for my flux capacitor - and maybe a Mr. Fusion to go with it...

 

mario.... if it helps... when I mounted my FMIC... I lost 4 lbs of boost... but I gained over 50 WHP!

 

Thanks for that - it's gratifying to hear nice things about my posts. Like I told another poster in a PM, I've actually got a lot of neat explanations about other phenomena in automotive engineering, but no one ever asks the questions!

I'm glad to hear some empirical evidence that goes along with my theoretical explanations. I'm limited in my practical experience by the restrictions of the autocross class I'm in (no air-water intercoolers for me..), so it's good to balance my physics-based discussions with the experience of people like you that have actually *done* the kinds of mods I'm theorizing about.

 

mario i'm glad you got the install finished!
and i'm glad you are seeing what i have been saying all along about this intercooler.
- john

 

You are so right! I want to put my 3psi on the back of a Milk carton, saying "Missing Boost"
I wonder if other Mini Madness or Ginanti customers are going through this?

BTW when are you going to drive down to my hood?
M

 

One place you don't want to loose boost is the IC.

Colder air is heaver air. Heaver is harder to move & the longer the distance the more energy it takes.

There is a careful balence of how you want to control the IAT with any IC. With your front mount the volume of cold air makes up for the boost ( there is a very long & involved method, there is no real formula, for figureing, -1# boost lost = X volume of colder air, not simple ). Great TE with a 8% loss of boost by volume could be very bad. On the other hand, high boost with very bat TE could be the big nail for your motor. It's about balence.....

There are many end tank designs that are designed to increase the air flow through the core & many core designs that reduce drag or, in short, reduse loss of boost. All really big $$$ & need to be designed for your application.

Efficent, heads, headers, exhaust systems would, for most, seem to reduce boost. The SC will still move the same amount of air it did before these mods. There is more useable system air - boost with these mods. You lost nothing in reality as long as you don't have a restricted air path area, in this case we are talking IC.

In Mario's case I'd bet that his new W2A, on a flow bench, has the same loss number as the OE piece. Scott's post explains it best. AND - this kind of boost loss looses nothing.

I'm looking at front mounts that can be easily installed, without cutting the bumper. The plumbing alone has a bunch of loss but worth it, if the core is big enough. Adding 50whp with FMIC, here in the NE, would be way more practical than W2A, we have snow, slush, ice, below 0 days. The water part of W2A is the only part that has some liability in the winter. The MM for $$$ spent is verrrrrrry tempting........

 

Not meaning to nit pick, but since there is already a high nerd factor in this thread it might interest some to know that unlike most fluids, the viscosity of gasses increases with temperature. So, colder air actually takes less energy to move than hot air.

On the earlier bits of this discussion, it is easiest just to think of maximizing P/T, rather than just P (or boost). P/T is proportional to density. Higher air density = more O2 into the engine = more power.

 

stock r56
seriously modded r53
i saw this first hand today, sorry for the proof
i could not believe until i wached it unfold

 

The physics universal gas law PV=nRT. Heat (T) is directly proportional to pressure (P). I am glad that your new toy is working well for you.

 

Hopefully the weekend of August 10th. Also, I am still waiting for Jan to get the new tune (Hydra or Giac) ready along with some projects he was working on. Aug. 7th is my Birth Day so the weekend before that on the 4th I will be with friends celebraing so I can't come on that weekend.

I will call you for sure when I'm making plans. Hopefully if everything works out right with Jan's timming and everything else the 10th should be the date.

I can't wait.

 

It only expands & becomes lighter. If you include the energy used to heat the air in the first place you would be right.

 

SR: "At this point, you could remove the intercooler as well, because without the supercharger heating up the air, there's nothing for the intercooler to do. The air flowing *into* the intercooler wouldn't be any warmer than the air flowing *around* the intercooler, so there wouldn't be any heat exhange taking place, and the intercooler wouldn't cool off the air going into the engine."

Should have thought of that before. You wouldn't need an I/C with air that couldn't be cooled in the first place....

 

who you callin a nerd sir?! I am a geek!

 

Hey, I happen to love the nerd factor in this thread thank you very much!

 

Thanks... this is why I started doing all the testing my self... as you know... sometimes the technical stuff is too much... and you just have to go do it... what's the saying.. "you gotta kill the engineer to build the car" or something like that..... I am someone who is very technical but not as much as those like yerself... and yes... at that point I just go to the testing... LOL... it all starts on paper though....

anywho... thank again for all your writing... You understand it far better than my self as I said before.... I have never been able to eplain it as well... LOL... I keep reading it thinking... yes! .. exactly! .. dang it why didn't I think of that!

ha ha no doubt!

 

Can you tell us more. Was it a dead stop race or a rolling? The R56 does get off the line quick but dies around 4500rpm. I want details!!! and so does MikeG4572

 

Yeh I want to know more myself. Not sure what he meant excattly about the:

"i saw this first hand today, sorry for the proof
i could not believe until i wached it unfold" ,,,,comment.

Is he saying that the r56 beat out the heavily modded r53?