Originally Posted by Northwest86 (Post 2666621)

The heat is a part of it. The other part is the fact that A stainless manifold for most applications is difficult to shape in anything but tubes. (cost effectively) The cast manifold only has to be designed and was refined once to get smoother lines in shapes that are not economical with tubular headers. The other one is Heat transfer. Now Stainless has low Conductivity which makes for hotspots and unequal temps. But since most (not all, I haven't seen a Ptuning manifold but most of the others I've seen including some Premium kits are made of cheesegrade thin stainless) Heat Transfered is a product of mass and thermal conductivity. Cast iron and Steel have somewhat similar values with some cast irons slightly less conductive. Stainless varies massively due to alloy but 316 for example would be about 1/2 as conductive as cast iron. But due to the mass the cast will hold heat better, and generally have less surface area. The thermal expansion is what makes cast so much stronger with cast expanding less than even steel. With stainless this stresses fastners, makes pipes and welds flex etc. Thats why with stainless manifolds you should always support the turbo.

This isn't my car but another guys with the same kit. He runs RON98 so 93 AKI? At the time of the dyno he hadn't gotten all of his exhaust parts and still had some stock parts. It's also on the wastegate so a EBC like mine runs would bring the boost on a couple hundred rpm earlier. The throttle response is what makes the difference though. The off throttle lag of Front mounts vs this setup is insane. The 2nd pic is mine with an EBC and 2.5" exhaust parts and a Q300. GTX30 modified turbo on mine. Tuned on 93 but conservative enough to run 91 with no issues. This is also a tracked car with no cooling upgrades apart from an oilcooler with no overheating issues in 34C days. Oh and I'm also running a Stainless Manifold as the Cast wasn't available when I got mine all done. Mines got a few prototype parts. I may end up getting a Cast option at some point or just getting mine Ceramic Coated.

http://i1082.photobucket.com/albums/...01685938_n.jpg

http://i1082.photobucket.com/albums/...led/THANE2.jpg

In terms of numbers, It's metric of course (Get with it USA) and he doesn't do internet dyno runs. My run was after been tuned and with just a small blower fan on a hot day with no cooldown period between runs. His dyno is also the lowest reading dyno I've ever seen and you should add a good 15-20% for most of the dynos you'll see in America. Stock is 105kw roughly on his dyno. To have a look at pics check out the Coyoda Technologies Facebook page and for contact Coyote Tuning's facebook page might be the easiest. He doesn't advertise to heavily as locally in Aus word gets around about his stuff and he's definately not short on customers.

BTW sorry If I'm butting in on your post. We all like turbos (Superchargers, eww) so hopefully it's alright. It's intersting to see how many different options people come up with when they keep developing these cars.