According the old SCC article, the newest design of the M2/ASP large intercooler has 22 cross tubes, vs. 18 for the earlier design.

http://www.sportcompactcarweb.com/pr...a_rx_7_part_9/

However, I'm looking at a local M2 large but the number of tubes it has is 15:



It definitely looks like the large in every other way. Perhaps this is a very early model?

 

FWIW, I just looked at a picture of my M2 Medium, and it has 22 tubes. I think the only difference between the two is the width. 15 seems significantlt smaller.

 

Yup - only the width should be different. This IC has been sitting in someone's garage since the late 1990s so may be an early prototype.

Probably not worth the risk - pity since it is effectively new and all the ducting and clamps have never been used.

Martin

 

They aren't the same core. (medium vs large) At one time kevin posted that the medium was a more efficient core than the large.


https://www.rx7club.com/showpost.php...91&postcount=8

 

By more efficient, do you mean the ratio between cooling capabilties to pressure drop?

 

More efficient per volume, he said.

And if you look at the SCC article I linked to, it clearly says that the early M2 large design had 18 cross tubes and the later has 22. The intercooler pictured has 15, which is why I am confused.

 

I figured that was a given. Why would he offer a larger intercooler with reduced cooling capacity? I was being presumptuous.

Your answer is right is in your comment. I don't put much faith in SCC, especially when it comes to RX-7s...who knows though. It could have been a typo, or they could have counted wrong, or kevin could have made some mid run changes. One thing's for certain, if you can verify that it is an M2/ASP IC and it's priced right, you can't go wrong.

 

Sorry if I may have sounded sarcastic. I put very little faith in SCC (though, that said, their RX-7 build-up is not bad, and stands up reasonably well after 5 years). I did some searching through old classifieds and the pictures I found have M2 large ICs with 18 rows or 22 rows. The seller has sent me other pictures and it definitely looks like the M2 unit, down to the duct extension that seems pretty rare now.