Gotta cool off those TWO T66s

 

HELL YEAH
I dunno where people are pulling some of these replies from, but it's scary to think that if you had no clue it actually SOUNDS reasonable...

-Ted

 

whatever dude, we'll see..

 

Barwick, The IC in the picture is for sale for ~1400.00, Save yourself some time, I'll blow through it for you, and everything

 

It's simple, the longer the tube the greater the pressure loss, but with a slight increase in efficiency, the length of the tube only effects eff. a small amount (very little) heat is going to get transfered the most where the temp difference is the greatest,(ie. first few inches of the core) there is very little heat transfer at the other end of the where temp. difference is minor, that being said it would be very interesting to watch on a thermal camera of some kind how much the sweet spot shifts around from hotside to slightly centered on the core while in use.

-Sean

 

Sean, maybe I can get the WGN and Fox news guys to let my use the thermal imager from the helicopter. I think I am still in good graces with them.

 

ok, whats wrong here , im not UNcle jet ski and how am I signed in with that screenname. This is weird.
1R1

 

Who the @#$% is unclejetski?

 

And just so you guys know your all both right to some degree, with me I would lean torward more shorter straws than fewer longer ones, but thats me, here is what one of the largest manufactures has said. When asked is one better than the other.

"No, almost no difference. With three decades of testing intercooler’s, we have found no appreciable difference between any core style or manufacturer. Keep in mind, that the merit of a core is it’s efficiency versus its internal drag characteristics. When sized for a tolerable flow loss, virtually all cores will produce essentially the same efficiency results. Perhaps a core with slightly less flow area per linear inch, or one with longer tubes, will need perhaps 5% more tubes to equal the best of intercooler’s with regard to flow loss and efficiency. Not a very important difference."


-Sean

 

so who wants the ic...

 

Is it possible to devulge your source?
Spearco, at one point, was pushing for the shorter (i.e. vertical) IC core over the longer (i.e. horizontal) IC core when designing an IC for your vehicle.



-Ted

 

It wasn't spearco, and even Mr."maximum boost" recommends the more shorter over less longer theory, I believe one of the reasons being more hot air getting spread over a broader cool surface, I don't quite remember who that was from, but I think it was behr or something like that.

-Sean

 

I'm (personally) convinced that the air will move SLOWER when there's more short tubes, than it would when there's less long tubes.

AND, if that's the case, then take Bernoulli's theorem into account (http://www.ceeo.tufts.edu/ldaps/htdo...bernoulli.html for those who don't understand how a plane flies), and that means that going fast through the long tubes makes for lower pressure and therefore cooler air inside the intercooler, whereas the more quantity of shorter tubes makes for slower moving air at high(er) pressure meaning higher temperature, therefore there's more heat INSIDE the intercooler to go to the ambient air.

How much that affects things I don't know...

 

Air might move slower but I would think that is due to more internal drag/friction, also since it wouldn't be traveling as far it might not matter how fast it goes, meaning if it only has to move half as far down a tube even if it was half as fast it would be in the core the same amount of time. Wow now that I read that I feel like I'm talking in circles. Hope it makes sense to someone.

-Sean

 

Hey did anything ever come of this?

Barwick's theories are correct.... The longer the tube the greater the pressure loss in the system. Plus the rate of cooling isn't proportional to the length of tube, after about 5" there is relatively little more cooling to be had.

I'm in the process of getting the ideal V-Mount made, so its certainly interesting to read this thread!

Does anyone know, without me having to run another temp probe, the exit temp of the air prior to the intercooler for a GT35-40?

Cheers

Atomic

 

ZeroR's info matches that provide to me by Bell.

Tube length, after a certain point, doesn't do much. It's producing air drag w/out significant cooling.

Ideally, you want a tall core (more rows), and a thick (but not so thick that it's difficult to force incoming cooling air through) to minimize pressure loss, and provide alot of cooling surface area. You'd want something around 3.5" thick on a turbo rotary, and wouldn't go much shorter than 11" if possible, and not necessarily worry about making the core 28" long. 18" is plenty. Of course, you'll ballance all three dimentions relative to the space you have available. I've seen some GTP cars with what looked like 8" thick, and about 10"x12" intercoolers, that were undoubtably used for packaging and frontal area aero considerations.

What I'd like to know is, which way to ballance internal vs. external rows. If you've got a 13" tall core, would you be better off with 20 internal and 19 external rows, or 19 internal and 20 external rows, all other things being equal?

 

His, current thinking is that longer rows are better (at the expense of the number of rows) since drag can be overcome by slightly increasing compressor output. He told me this when I called to order a core. His said he is going to cover this subject in more detail in his next book.

 

Bell told me just the opposite... that more rows, particularly internal, were favorable over tube length, for the reason sean stated... there isn't much cooling happening at the end of the row, since the charge air has reached a temp that is close to the ambient air being flowed through the core fins.

 

This is my findings too, which is why im looking to run the tanks east/west instead of north/south as I have at the moment. My current core is only 11 sq inches internal flow area, and Im seeing inlet temps of almost 80 deg C....not good!

I do need to find what the outlet temp of the compressor is though so if anyone knows

 

Not sure what to tell you there. I was about to buy a $900 core from him and he suggested that I orient the rows the other way. I pointed out that it contradicted what he said in the book (I had read that section a day earlier). He said pretty bluntly that he revised his thinking on that and will be releasing a new book. Like any thing else there is a cost/benefit balance, so you may have gotten a different answer based on the area you have to work with. I am trying to fill a 24x4.5 x 15" box. For a vertical core, that leaves about 8.5" of core length. He said I would be better off running the fins the other way even though it would cut the cross section in half and it is going to be used with a 3 rotor that has a big turbo.

 

Right. Because 8.5" is too short a tube length and 24x4.5" is overkill for number of rows... whereas in the 24" dimension, you can get about a 18" tube length, and a nice tall core with lots of rows (15").

4.5"x15" provided PLENTY of flow area, and got you the longer tube length you needed from 8.5".... which was probably optimum at 16-18"... not 28 or something.

I did the same with a 13" high, 18" tube length, 3.5" thick core.

 

Not necessarily. When I first approached them a few years ago they suggested the shorter setup and though the length was ok. You're right a 24" wide core is more than enough cross section and some cooling efficiency is being needlessly traded. We got there initially because the flow capacity of the other setup is margin for my application. That was conversation one. When I went back to them a few years later they suggested I use the longer core and said their logic has changed. I'm not trying to bicker over details. I just to be clear that both recommendations came from BEI, each based on a different thought process, for the same application.

 

I run a 18L x 13.5H x 4.5D It is bellmouthed and baffled internally and that was a pain to do but worth it as far as flow goes. I can grab my compressor nut and spin the comp wheel by hand and feel the air coming out the IC oulet tube which is about 12" long. Not bad at all. I prefer staying shorter if possible. This is me. I say this because in my mind raising boost to overcome core length is adding heat to which you then need the added core length. You will notice a considerable amount of lag when going from a 18" length core to a 24" length core. Call it drag, call it whatever you like. Running both 18" and 24" bell cores and garrett cores. I'm sold on running 18" cores for anything on street levels of boost. ie 25lbs or less. The car just seems to have quicker response. When starting to bump 30psi and up that is when I consider the longer cores. The key thing to remember is the obvious, your trading one(flow) for the other(cooling) so if you need the longer core then you need it. But if you're not running huge amounts of boost with a smaller less efficient compressor, I lean torwards the option with the better flowing core. That is what I do, and it seems to work great for me. IC stuff seems very confusing at times because you can come up with more than one solution for the same application and still have the problem solved. Gerhard by the way, is a very very knowledgeable man, who has worked in formula one and too many numerous other places and really knows his stuff. Just thought I would throw that at there

-S-

 

I run 20psi daily on pump gas (we'll leave the octane out since that isn't the point right now.) Strange how things change in just a couple of years.

Based on personal experience (dimensions can be added later) my Apexi FMIC was showing about 12C temperature increase in a 40-140mph testing run when at or above 17psi. The Greddy 3-row shows 0-1C increase in IAT for the same ambient temperature (within 2 degrees) conditions, the same turbo output, the same tune, the same scenario. Even at higher boost no more than 0-1C of IAT increase.

Is that a measure of effectiveness? The change in FMIC negatively impacted spool-up by ~200rpm with the longer "pipe run." How much harder does the turbo have to work now? I don't know.

Edit: I think I am agreeing with a couple of points you are making Sean. There is a sweet spot for every targeted application between factors. I used the terms spool up and maintaining IAT level during "performance driving." The Greddy longer pipe runs did take away from spool-up and general "snappiness" but at a benefit of cooler IAT across the board.

Tony

 

Here's the other problem with it, that needs to be considered. At what pressure was your cores CFM rated at? I say this because some cores are rated at higher pressure than others, so.... here is one core rated at 650cfm at 10psi and another rated at 650cfm at 17psi. You can see that the problem this creates. The higher the pressure, the higher the acceptable pressure loss, so the higher your flow rate. Manufacturers are asses in that they have no "set" standard. Find out what your manufacturers test pressure is. It is in your best interest to pick the one with the lowest test pressure as it will give you a conservative sized core that allows room to grow.

-S-