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Alan L Alan L is offline
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Join Date: Apr 2006
Location: New Zealand
Posts: 3,276
Great post Cole. I want one of those airplate things. I know there is a whole thread on this somewhere, I think 911st was posting on it, and maybe your good self.
On the Q of the airfilter, what would the advantage of the inclined stack be, over a straight K&N vertical filter, as I have directly over the airplate?
I definitely want some of those 'free' 420 horses.
Here is a copy off one of those;
The bottleneck gets moved around, But it can never be removed from the equation,

Achieving the necessary air flow capacity upstream of the turbo ( on modified engines) can be addresed by :

1- Re designing the ducting between the A/F meter and the turbo
2- Modifying the A/F meter (cone and Plate)

When these components where designed the target output in conjunction with other relevant factors gave us little room for increased capacity.

When Porsche began testing the 930/71 (934 motor) bosch engineers approached the restriction of the A/F meter by enlarging the diameter and changing from a metering disc to a cone, This BTW had the side effect of poor fuel mixture progression, The location of the unit was selected so that a short duct could be used into the turbo inlet.
These mods where deemed necessary for a 485bhp output

lowering control pressure should be used to allow the engine to accelerate not as a way to reduce the restriction of the A/F meter, 86-89 engines used this strategy by changing duty cycle of the fequency valve during acceleration

As we look at flow capacity in these components we also stand to gain compressor efficiency while reducing lag,

I personally would first focus on the ducting, soon hope to have a solution, then slowly realize that it is very easy to reach the point where EFI becomes the solution to most of these gremlins,


BTW, thanks , as I see this becoming a very interesting thread.
here is a link to the thread I think I had in mind
Advanced CIS Turbo Tuning Discussion Thread. Ultimate?
83 SC, 82 930 (track) - Stock except for RarlyL8 race headers, RarlyL8 Zork, K27-7006, 22/28 T bars, 007 Fuel head, short 3&4 gears, NGK AFR, Greddy EBC (on the slippery slope), Wevo engine mounts, ERP rear camber adjust and mono balls, Tarret front monoball camber adjust, Elgin cams, 38mm ported heads, 964 IC. 380rwhp @ 0.8bar Apart from above, bone stock:-)
Old 03-10-2012, 11:59 AM
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