Originally Posted by Mike Benvo
Just wanted to post an update after speaking with a few of my friends in the tuning community that have had experience with these stacks.
It turns out that it sounds like the company that makes them actually know what they are doing. When fitting them straight away without any tuning, the car lost significant power on the dyno. But after consistently redynoing the car without making any further changes to the software, they actually made power after the car was able to adapt.
Furthermore, there was a customer that wanted to order them. He explained to the company that his car had aftermarket camshafts. They told him that the product in their stock form would not work properly unless the camshafts were stock, as the length of the stack is calculated by them and timed to the valve opening events. They wound up making a specific stack for this customer with a change in length to account for the different camshafts that were fitted. This shows a clear understanding by them of the relationship between the length of the stacks and the cam profiles.
Now if only they had a way to incorporate airfilters on top of the stacks, I would probably consider them for my car.
Hope this helps clarify real world experiences with the use of these stacks.
Originally Posted by BMRLVR
Not a lot of headroom is required to achieve full flow characteristics of the stacks due to the nice smooth bell mouth opening that funnels and directs the airflow.
FMU are not dummies....... They have been in the VW/Audi scene for many years now and although I am not a fan of how they like to slam every car they turn out, their past projects speak for themselves. It takes considerable R&D to engineer and produce a piece like this.
Your talk of camshafts sounds like a person who had replied to this post in a few replies above
+1 FMU have been around for a bit and do build some nice things; surprised you've never heard of them esp. considering your part in the BMW community. They are def not amateurs