| Well, got some really good data today at the flowbench and have compiled all the data for review. Recap:
Original prototype of turbo inlet pipes, Feb 28.
2.25" o.d., 2.12" i.d. mandrel bends used to get around manifold shields and engine mounts, expanded out to 2.5" o.d., 2.37" i.d. upstream. As large as the tubing can be to fit. 8% and 15% improvement over stock inlet pipes, 3% variation between sides. 
V2 inlet pipe prototypes built, March 7. Full 2.5" o.d., 2.37 i.d. mandrel bends used in conjunction with BDE engine mounts for clearance. 
Issue: Turbo compressor inlet geometry uses a 2.1" i.d. and poses a bottleneck for the inlet system. Machined adapter flange for the full 2.5" prototypes from 1/2" plate with taper transition from 2.37" i.d. to 2.1" i.d. to use for comparison vs. the original prototypes to see if the 2.1" restriction at the turbo compressor housing negates the benefits of using a full 2.5" inlet pipe. 
Performed flowtesting of a complete 2.5" induction system - replacing all OEM parts from the filters to the turbo comp inlets with mandrel bent 2.5" tubing and comparing total system flows using various turbo inlet pipe configurations. 
The results:
 The first two results are using the V2 full 2.5" turbo inlet pipes attached to the complete induction tract. These also have the transition plate attached which limits the cross section to 2.1" dia. The second two results are of the V2 full 2.5" turbo inlet pipes attached to the complete induction tract. These do NOT have the transition tapers and have a full cross section of 2.37" dia. #5 and #6 are the V1 inlet pipes attached to the complete induction tract. These tubes have a cross section of 2.12" at the compressor flange and open to 2.37"i.d. for the connection to the rest of the tube system. And finally, the last two are of the complete original induction tract for driver and passenger side. TOTAL Combined flow (both driver and passenger side)
V2 w/transition: 796CFM
V2 w/o transition: 917.3CFM
V1 : 752.4CFM
OEM: 584.5CFM 752.4CFM for the V1 pipes and 2.5" lead tubing - The V2 pipes w/transitions had an increase of only 5.8%. This directly represents the effect of the limiting 2.1" inlet at the compressor housing on the V2 inlets. There will be a gain of 5.8% in using the V2 inlets and turbos with 2.37" i.d. at their flange. It will require modified compressor housings and BDE mounts to fit them. For the vast majority of folks, the gain of 29% using the V1 pipes and complete 2.5" inlet system upstream compared to the stock plumbing is going to provide notable benefits in performance for less cost in both time and money. Referring back to the flow demands of the inlet system based on engine RPM and boost level we can see what improvements this new system will offer. The V1 pipes with full 2.5" lead will offer less than 1psi of pressure drop at 18psi of boost up to ~6500RPM - right about where torque production in our engines starts to fall on its face. This is an improvement by ~1000RPM compared to the stock inlet system. 
The relationship of pressure drop relative to flow volume is exponential. The linear plots shown above only illustrate the flow demand of the engine. If one were to plot the pressure drop relative to flow through a given intake system it would reveal an exponential relationship. I might consider taking these parts back to the flowbench and plot flow percentage relative to pressure. 0 to 28", 4" intervals on the manometer. The datapoints could be used to further extrapolate the required pressure drop to move an increasing volume of air beyond what the flowbench can produce. The results of this will further illustrate the benefits over the stock piping, primarily up in the racefuel boost levels. In addition, I also flowtested JUST the V2 inlet pipes without the transition plate and got some very nice results.
Driver's Side, V2 2.5" w/o transition : 529.8CFM
Pass Side, V2 2.5" w/o transition: 516.1CFM
TOTAL COMBINED: 1045.9CFM There is a total loss of 128.6CFM induced by the lead pipes from the filters to the turbo inlet pipe interface. Even if 3" replacements were used in these positions there will still be a reduction in flow, not as large as with the 2.5", but even it we presume it will only be half, the system will flow 981.6CFM. A 7% increase in flow, presumably. Routing 3" tubing underneath the headlamps isn't impossible, definately challenging though, and would not be a direct bolt-on affair. Modification to the unibody is guaranteed. Will continue with these efforts and see what will be required to pull this off. The goal I was shooting for of 750CFM total was achieved using the V1 inlet pipes and a full 2.5" system from the filters to the inlets. This improvement in flow should be easily seen in dyno testing, which will come soon. But for those who are going all out with their builds, we will make the V2's available and offer new turbo housing flanges to mate with them. More testing and fabbing will come to entertain using 3" lead pipes, but I think those kits will be reserved for a smaller group of owners. More to come.. Enjoy these video clips at the flowbench:
[ http://ashspecz.com/Web%20Documents/TurboInletDevelopment/P3080364.AVI ] :)
[ http://ashspecz.com/Web%20Documents/TurboInletDevelopment/P3080365.AVI ]
(maybe I enjoy my job too much)
Enthusiasts soon understand each other. --W. Irving.
Are you an enthusiast? If you are out to describe the truth, leave elegance to the
tailor.
Albert Einstein
|
AshSPEC Turbo Inlet System > Final Flow Results, Analysis> - 
