People tend to wrongly associate larger ICs as utilizing the same air passage count and density when that's almost never the case.

Once again, the GN group's page:

http://www.gnttype.org/techarea/turbo/intercooler.html

 

Bleh I'll try to answer it fast I guess. Dcrosby you kind of answered your own question. Air does take the path of least resistance. As I explained above with pressure drop this follows closely, as one charge row fills with air its pressure rises, empty rows below it will be at a lower pressure and as you mentioned air wants to take the path of least resistance and will flow to them, essentially like a cascade down the entire core, as one row's pressure rises air will flow to the next row to equalize. This is of course a horrible over simplification as air won't just go in the top row, then the next below it etc. We'd need a supercomputer to model the actual flow inside of any endtank, but the pressure seeking to equalize itself still holds true which is the important part based on what I assume you're asking. In short whichever row gets airflow first will increase in pressure and air will then move to other charge rows until pressure is equal throughout.

Okay you made me do it. Here comes the hypothetical straws.

Put a straw in your mouth and blow through it. Use a moderate diameter straw that you can actually exceed its flow capacity so that your cheeks fill and bulge out. Now put another straw in your mouth wherever you like and again blow. Air won't just travel through one straw, pressure will equalize and essentially the same amount of air will travel through both assuming the same diameter, length blah blah.

Is that what you were asking?

Kevin T. Wyum

 

Good article Clayne although I like my straw examples better : P kidding. Most people won't want to read the whole thing sadly, for those that do it's a good read. I just did to make sure it agreed with me : P.

Kevin T. Wyum

 

Kevin:
How about the air temperatures for both medium and large?... Given the same senario. What are the differences in degrees?... How much cooler is the large?... Does an extra 5x13 inch core make a big difference in degrees?

 

So Kevin, I was trying your experiment...
.

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
And then something went horribly wrong...
.

 

And back on topic...

Having the in/out pipes at the top of the core is not the ideal spot for them from the perspective of having equal flow through the whole core. However, there are other concerns to consider (packaging, pipe bends, where the most fresh air hits the core, etc.), and I think the final design was a very reasonable choice that has proven itself in testing (pressure drop + intake temps). The air doesn't just flow through the top rows for the reasons Kevin laid out. And if it did, the pressure drop would be large. The pressure drop isn't large (in fact just the opposite), so it's clear that the air does indeed flow through the whole core and not just the top rows.

-Max

 

 

That's too funny Max : ). Back on topic, yes there are more ideal ways to do it but unfortunately there are restrictions to layout based on space, input output sources and where pipes need to end up at. All of those cases are a matter of picking the lesser evils as you hinted at and of course the biggest limitation of all is keeping price within reason. If money was no object I'm sure I'd change a number of things but we also get into the world of diminishing returns of performance for each dollar spent and I honestly feel the end product after these years of refinement is the best overall balance of those many many factors.

Fun discussion so far.

Kevin T. Wyum

 

Sorry lagged a bit and got a double : (

 

^ Kevin: ^
How a differences in temps?

 

Nothing handy right now RX7UP. Just from memory over the years, the pressure drop is essentially the same and the charge cooling for the large was on the order of about 3% to 6% better at higher speeds, 20mph through the core, and closer to 10% at lower speed, 5 or 10mph through the core. These are strictly from memory so don't grill me if I'm off a bit : ). The reason for the increased difference at low speeds is the medium core has a more densely packed array of fins on the amient side of the core and it's harder for air to pass through it, but that's also why it performs better per CID at higher speeds. That make sense?

Sorry I couldn't respond sooner.

Kevin T. Wyum

 

RX7Up,

I think that data is on scuderia's site....

 

7racer:
Can you post the link?

 

Start here:
http://www.scuderiaciriani.com/rx7/i...olers.html#ICP

 

Cool, thanks Art. I have to say I'm kind of impressed by my memory on the percentages I mentioned heh.

Is the 4" thick Greddy front mount the 3 row people talk about or the 2 row?

Kevin T. Wyum

 

Hrmm nobody knows?

Kevin T. Wyum

 

I'm pretty sure it is.
Here is a shot of the ASP next to the 3 Row.

 

Damian,

have you had a chance to install the ASP medium?

I am having some PITA fitment problems...

I definitely need the airpump friendly pipe as I cannot attach my strut bar.

Also, with my rx7fashion airbox, it pushes the intercooler to the drivers side. We had to scavange a old M2 pipe to get it to fit.

Also, I have a fluidyne and widefoot mounts...even with the fluidyne as low as it would go...the intercooler duct sits high on the fans and I can no longer close my hood prop as the duct prevents it from closing properly.

Just wondering if you (or anyone) had any pointers or tricks...

 

well, i dont have it all together yet, but my intake gives plenty of room, no fitment problems there, and i have the stock radiator so my duct fit in just fine. I also removed the airpump so I dont have an issue there either.

Icant say if the pipes all fit right yet or if I have any hood rubbibng issues yet since I have not had it all plumbed togheter yet, but I plan to have it all together later today.

 

dammit! With the airpump out and the intake that you have....it will fit fine...

I on the other hand am having "issues"

lol

here is a quick pic

 

yeah, I dont have an air box, just filter with a heat shield so I have a lot of room on that side, and no airpump means I have the no-airpump tube that clears everything fine so far, although I didnt put the tower brace back on yet, roads were wet but i did take it for a slow ride around the block and it all seemed fine, nothing bumpin my hood that i could tell. I'll get a pic up soon.


it looks like your duct is carbon fiber? or did it just picture that way? i am pretty sure mine is fiberglass

 

7Racer:

Does the asp come with that carbon fiber air duct?

 

No it is fiberglass....just wanted a different visual effect. It is custom work done by Mark Koch at carbonfiberparts.net

I talk about it in this thread...

https://www.rx7club.com/forum/showth...hreadid=274682

 

A lot of people have aftermarket radiators used with the kits so there is certainly a way to make it work. Maybe someone that has can jump in.

I'm not sure which pipes you're talking about though since the kit appears to be one made by M2, I've never made a pipe like that driver side one and the normal passenger side tubes I make aren't intended to fit with the airpump. I was pretty amazed people make them fit somehow, they weren't designed to. That of course all changes once the casting is done for the new pipe.

That airbox does look a bit big. I wish I could be of a little more assistance but other than the air pump pipe when it's done I can't do a lot to support what M2 sold. Sorry : (


Kevin T. Wyum

 

7racer-

I have a simular problem, am waiting on the new tube to clear the airpump.

I also have the RX-7 fashion intake, but what we discovered is that I was sent the pipe for the large IC instead of the medium. I think I am also going to have to shave the battery tie down off and just use a bungee cord because it rubs the IC pretty good.

Thats interesting you have had an issue with the fluidyne. I have one in my gagrge ready to go in. Don't know about the widefoot mounts though or what they are?

Anyway Jason and Kevin have been extremely helpful in getting my issues resolved.