Quote:
Originally Posted by RPiM5
Akropovic makes +10hp and like +7tq I think. Yes it's very lightweight and strong due to the titanium, and it's build quality is literally second to none. That exhaust system is not built with power in mind, it's built with quality, aesthetics, and sound in mind, and it really does do all of those 3 thing very very well.
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Here is the link to the dyno graph (PDF file) listed on Akrapovic's site:
http://az79640.vo.msecnd.net/akrapov...2056fd4ec2.pdf
From the dyno sheet it looks like it only has minimal lag on the low end compared to the OEM exhaust but catches up and surpasses near the mid-to-top RPM end.
and the product website for the F10 M5:
http://www.akrapovic.com/en/Automoti...ProductFilter=
I wonder if the conservative performance and sound might have been influenced by the EC-Type Compliance that Akrapovic got certified for? Anyone from European countries know a thing or two about this? I'm assuming it's relating to noise and/or emissions? Not every customer is looking for a drastic increase in exhaust noise or only peak power.
Quote:
Originally Posted by RPiM5
RPi is instead planning in removing the down pipes from their own F10 M5 for product development. The RPi down pipes will completely remove the primary cats for great exhaust note decibel level and much greater airflow thereby creating much more power. The projected difficulties right now are that BMW uses cast iron for the stock down pipes, which is great because it is extremely heat resistant and strong. Trying to use another alloy that is lighter and just as strong as cast iron will be a challenge for development because of the extreme heat generated in that area. You can expect that RPi will release its GT down pipes next year. So stay tuned!  |
I would've thought that was the intended purpose of a shop's project car to use for shop development.
In all seriousness though, what about aircraft grade 321 stainless steel or even better yet inconel? Ceramic coating as an option to keep engine bay temps down as well? I'm wondering on the necessity of the higher grade stainless or inconel, though. Assuming the part is designed correctly, the rotary turbo guys, as well as GT-R, Evo, etc. still use 304 stainless (a common stainless steel that most aftermarket tuners will use) without worry of fatigue or cracking - and rotary turbo exhausts can get hellfire HOT!
I think it'd be great to post up the results of the dyno exhaust test shootout.
