Why were no SMICs that use OEM pipe routing ever offered in the US ?
 

The title is a little misleading, because in fact CX Racing offers a SMIC that works with their copy of an M2 CAI, but they have so many complaints about service and product quality and expecting you to pay return shipping when there are problems(even though it's already factored into their $170 kit shipping costs) and reports of them being unresponsive at times ...I think I'll just keep patiently looking for a Japan ARC or Cusco SMIC, that rarely leave Japan. There's an issue with used intercoolers being shipped overseas if traces of oil are found, due to flight safety regulations, I suspect ? Your Yahoo part purchase could end up staying in Japan if inspected and flagged as having traces of oil residue.
SMICs are, or were, such a large untapped market, Prices for new ones seem crazy compared to the cost of comparable quality Koyo aluminum radiators.
There are bends in most SM intercooler sleeves,such as Blitz or Trust/Greddy, You end up having to use their pipes or custom pipes, which inflates costs closer to those of front or V mount intercoolers in the end.None of it adds up for me..
Your thoughts on this .. or personal experiences ?

https://cimg0.ibsrv.net/gimg/www.rx7...77542dce84.jpg
CX racing above - the IC is upside down, ARC Abbey Road below
https://cimg6.ibsrv.net/gimg/www.rx7...54185c1b33.jpg

They sold stock mount intercoolers that fit with stock battery box and stock intake and used stock intercooler hoses and shroud.

From memory some available in US were-
Rotary Performance
SR Motorsports
Greddy
Blitz

I have a Pettit one I used to use back in 2012-13.

I did like how it had stock like response unlike the larger ASP intercooler I am using now.

The thicker than stock intercoolers don't fit that great with the stock (or aftermarket piping) since it pushes the lower 90 degree bend into the accessory belts.
The Pettit one has a square top and bottom, so it doesn't fit as well as it could with the stock intercooler duct to airbox crossover plastic tube.

Tight S bends like the stock shaped turbo outlet to intercooler inlet pipe are horrible for flow by the way which is why M2/ASP/Pettit Med, Lrg intercoolers eliminate this design with horizontal flow cores.

https://theansweris27.files.wordpres...ar-scene-1.png

there was also the PFS but it came with its own poorly designed airbox that most people eliminated.


https://cimg7.ibsrv.net/gimg/www.rx7...db81c3e43b.jpg

Thanks for the info guys.
I never test fitted a thicker intercooler, but I can imagine it being a problem, as even stock clearances are pretty tight.
I have Apexi cast IC pipes I can use, if they will clear pulley belts. I suppose I could make custom mount IC brackets and trim the air shroud if need be.
I would rather live with air flow restriction at 90* duct bends than switch placements to straight horizontal.and lose space on either side of IC.
I'm less interested in power gains, than eliminating all plastic plumbing + potential leak points.
I think I would rather spend $$ on a Series 7 or 8 y-pipe, decent clamps + silicone hose joins.

My blitz SMIC worked fine with stock piping. It fit nicely with stock intake and airbox

I have the RE Amemiya cast pipes and I was not able to use them with my thicker than stock small stock mount intercooler.
This is because with the thicker IC core the bottom coupling has to make more than a 90 degree bend. It could be done with a 15 degree bend coupler (couldn't find one in right size/color) to the S bend hard pipe.

To have enough room I had to ditch the bottom coupler and use a 90 degree silicone coupler to the stock plastic top part of the S bend.

One nice solution is the Knight Sports or Knight Sports style small stock mount intercooler.
It straightens out/simplifies the inlet/outlet and has the thickest core with its U bend layout.
https://www.rx7club.com/attachments/...r-p4270096.jpg
https://www.rx7club.com/attachments/...mic-intake.jpg

I also have that setup (PFS cold-air intake and SMIC) with air-cleaner box modifications (removable top) to allow easy air filter removal and a divider in the IC duct to let less hot air back-flow into the engine intake. Also did the AdamC cheap bastard modification along with a larger duct from the PFS intake duct to the air cleaner enclosure. Subjectively, it seems to work pretty well. Other mods in my signature.

How thick is that core? I'd think a really thick core would lower the IC's heat-transfer efficiency because the ambient air going through the fins warms up as it passes through. For any heat exchanger thinner is better if you can maintain enough fin area and air-flow velocity.

The Blitz SMIC fits with stock everything. Piping, airbox, battery and ever crossover duct. Here's an old pic...

https://www.mazdas247.com/members/Na...7/FD_Blitz.jpg

Yes, that would improve the efficiency since the rear section's delta-T would be optimized by passing the hot compressed air through it first.

OTOH, a thicker core reduces flow velocity and, thus, heat transfer.

This intake is sweet, does it work with a stock intercooler? What do you need to get it to work with a stock intercooler in the stock location? Do you need another duct?

Intercooler testing
 

I did some intercooler testing about one year ago. This is low velocity or low air flow testing to look at intercooler efficiency. You use a higher end salon style hair dryer, a dual temperature sensor, and two high speed 300 cfm Spal fans (which I actually use on the car to increase air flow through the intercooler and intercooler duct on my current rebuild) to simulate air flow through the intercooler duct when the car is moving. here are my results on the stock intercooler, a GReddy SMIC I used to use and my current dual pass U-type SMIC that is from Australia and copies the Knightsport design but is actually slight larger. Here is the formula for efficiency.
https://cimg2.ibsrv.net/gimg/www.rx7...c60bd12a18.jpg
Here are the results.
Stock- approx.58%
GReddy- approx. 81-82%
My current dual pass U-type- approx. 88-89%

What I don't know is the pressure drop of any of these. The dual pass is likely greater, but makes up for this shortcoming with higher efficiency. Here are some stats I found on this site and from Knightsport which may be of interest. The Knightsport surface area is from their older dual pass design, not the current dual pass design or Type II.

https://cimg5.ibsrv.net/gimg/www.rx7...d9c4a72309.png
https://cimg6.ibsrv.net/gimg/www.rx7...0a17c9475f.jpg
Here is my current setup on my car from my just finished rebuild. I am currently road tuning. Every intake pipe, the LIM, the UIM, all the manifolds, the SP KAI still sequential twin turbos, the intercooler, and the downpipe are ceramic coated either in barrier or dispersant, depending if you want heat blocked or heat transferred. The UIM and LIM are extrude honed for matching airflow and increased flow, the exhaust manifold is mildly ported at the engine side and is ported at the secondary turbo to match the primary side (this can be done with still about 2-3mm of overhang for the secondary door to shut fairly tight), and the throttle body is ported by RC Engineering. The Autoexe air intake and the intercooler duct are coated on the inside by spray insulation and the Auotexe intake has a 500 cfm fan in it that is PWM controlled of heat by a Fan controller and an AIT sensor in the side of the intake. My Abflug CV bumper has a metal divider that divides cold outside air from radiator air so that the Autoexe intake only sees outside fresh air.

https://cimg4.ibsrv.net/gimg/www.rx7...a748c18948.jpg
https://cimg5.ibsrv.net/gimg/www.rx7...990d377cf7.jpg
https://cimg8.ibsrv.net/gimg/www.rx7...37392236db.jpg

Those ducts are composite and don't heatsoak, so what's the point of insulating them?

Mike, great data and info there.

Pressure drop is usually measured by comparing 2 boost gauges before and after the IC. A lot of it is down to the design of the IC itself and how the core is constructed.

In general, the more mass an IC has, the better. It's a big heat sink, you want a lot of mass to absorb heat and radiate it away. You also need a good supply of fresh air to flow over the IC to pull the heat out. Good ducting can make a substantial difference.

Dale

Good question, Narfle. I debated this with some of my engineering friends from Boeing and did some research. I found that pure carbon will not heat soak but the typical carbon fiber used in automotive does due to the fibers and possibly other additives in the adhesion process. To help find out, I put my intercooler duct in my oven to about 180 degrees and it did heat up quite a bit. Not nearing as much as metal would, but still it did. So I decided to coat them both just to be as thermal efficient as I could. Rather easy to do and used a product called Lizard Skin, used in both sound and heat insulating of cars. I used the insulating version.
Mike

Adding one thing, I did retest my dual pass U-type current intercooler after ceramic coating. I had the fin area coated in dispersant to help in heat exchange and the bottom and top in barrier. The efficiency only increased to 91% from 88-89%, which was kind of disappointing. Some of the reason may be that the efficiency was already quite high and getting it higher is hard to do. Also, I don't know what the efficiencies are in real world when in the car at higher flows or velocities and higher heat from the turbos. My hair dryer testing air temp input was around 185 degrees, while the turbos from what I have read, will get up to 280-285 degrees at WOT pre intercooler with no pre turbo WMI. In my picture, you can see a temperature sensor in the crossover pipe. I added it to do more real world testing on the road once I am tuned and ready. I will be able to compare air temps pre and post turbo and air intake temps at the air box.
Mike

Not that I want to dispute your experience, which is MUCH greater than mine, but here's one of my nerdy comments on stuff like this:

Having a large thermal mass is not necessarily a good thing for a heat exchanger. Theoretically, all a large thermal mass does is slow the change in temperature of the mass itself and lengthen the response time. What you really want is a high fin area and high internal air-contact area along with a very high thermal conductivity between the heated, compressed air and the ambient air so that the pressurized, heated intake air is cooled as efficiently as possible.

So although thermal mass often correlates with high fin and internal contact areas because they require a larger heat exchanger, it is not the mass that's making it better, but the other things I described above.

Almost all of that increase (likely at least 25 rwhp) is from the change in intake. You are likely seeing 2-3 psi increase in boost. The stock intake is so restrictive that it wont allow the rest of the system to flow like it should.