turbofan wrote:Ed Lijewski wrote:Another of several reasons why I like and run with the TCIC top-mount:
"2006 MAZDASPEED6 Exterior, Interior, Performance, Safety, Gallery ...
The intercooler is top-mounted, rather than front-mounted to reduce polar inertia. ... The overall result of MAZDASPEED’s effort is greater low-end torque, ...
[
www.mazdausa.com/MusaWeb/displayPage. action?pageParameter=modelsMain&vehicleCode=MS6 - 48k - Jan 9, 2006]
Note: although Google Search brought up the above on reducing polar inertia, I couldn't find the actual text in which it appears. But, I don't doubt that it's there, somewhere on that site. The physics involved re polar moment/inertia is unassailable.
YMMV

the performance advantage of a front mount is well worth the SLIGHT and virtually unnoticeable (on a 3000 lb car) change in polar inertia. top mount is just a lazy way to go, it's what you do when you can't front mount. the cowl induction is probably the best way to go where front mount isn't possible. top mount directly isn't bad... but it's not great either.
Lots of blather there....
Polar inertia is a factor to consider for autocrossing or racing or even spirited country lane cruising. It's unimportant for stoplight racing.
Top mount allows you to keep the a/c , uncompromised. You don't like a/c? Many of us do, a lot.
Top mount minimizes to the nth degree the necessary hose job (as well as typical regular re-adjustments required often on some installations).
Top mount is easily R&R-ed for plug/wire changes and other repairs to hoses/ turbo, HCV, etc.
Top mount provides sufficient lowering of air charge temp to prevent detonation (what intercooling is all about at essence).
Top mount with provision for additional air flow to/around it (easy to fabricate) or with fan-forced air to/around it reduces further air charge temp.
Top mount, hoses, additional plumbing for fresh air if desired and fan if desired can be had for ~$125. And for ~$75 or less get a PE or LA3 and feel the huge difference.
Did I include that installation is a, um, breeze?
Looking for the absolute best is a trap--there always are compromises with any system or technology. If one is building a real powerhouse, go for the best you can find and afford. On that kind of chassis/engine, top mount doesn't deliver the expected goods.
But, as the Mazdaspeed 6 shows, a top mount is all most of us really need. Certainly Mazada engineers think so.
Or, if you disagree, point to dyno figures showing the differences among ICs; most of that will be at the uppermost RPM range, territory that few among us inhabit or for more than brief moments.
Top mount is eminently streetable; just don't run for pinks with it.
YMMV
