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Original 928MS Intake and air filter 3" intake elbow and large K & N type filter. Partial cold air intake.
New dual cold air intake. Two 3" cartridge 9833 Spectre in-line air filters converging through a 3.5" Y to a 3.5" intake elbow.
The asymmetry of the intake is due to the off-center SC intake due to its internal belt drive.
The first picture above shows the original 928MS SC intake design. With its inter-cooler, I think it was probably working just fine. It did bother me to go from an advanced, for 1977, cold air intake on the original 928, to the design in this first picture. Probably stupid of me.
I tried to solve the problem of navigating from the original intake funnels to the supercharger inlet, which is a pretty compact space. My system just makes it, and the two filters are rated at 450 CFM each, so I think they will not be very restrictive at any RPM that I will ever see.
Thanks for watching,
Dave
We have tested the cold air intake on that 16v supercharger kit on a chassis dyno. (This is the first of the three pics that Dave just posted for those not familiar) Anyway, we found no significant loss of HP by using the air intake as we shipped with the kit. I say "significant" only because it is expected to drop a very small amount of HP when drawing through an air filter, and that is all we saw. This amount we see on any dyno when we run with and without air-filter. Usually within the margin of error of the dyno, and pretty hard to quantify. It's there, but its slight. I have tested our cold air intakes many many times like that (with it on compared to with it off) over the years just to confirm they are not restrictive.
Hi Carl.
I have no doubt that your original intake works great, like I said. My project should be considered as an esthetic and conceptual exercise to keep the original 928 cold air intake funnels in a functional system. I am absolutely positive that they will afford no benefit and hopefully no harm, compared to your system, in any driving condition I am likely to encounter. Also your air filter is probably slightly bigger than my two filters, put together.
BTW, I hate all the silver band clamps, because my assembly looks like some kind or overcooked holiday roast. I am going to replace most of them with black, heavy duty zip ties so they disappear.
So at least one more picture will be coming.
Thanks for a great product for me to tinker with.
Dave
I did mine for a couple reasons, none of which were that the car didn't run well with the setup that came from 928MS.
Reason #1 was that I wanted to capture and then compress air that wasn't as warm as would be if picked up directly behind the radiator - I understand that some non radiator air does come through the scoop in the top block off plate, but with the cooling fans running, believe that bit of cool air probably gets overwhelmed by the warmer air coming off the radiator, and since the filter isn't shrouded in any way on that side, will pick-up whatever air is available. Also if the fans are running there is likely some turbulence to that air, so may not pick up and smooth out as quickly as possible. My intake draws from the fender and has a fairly direct and gently curved path into the rear of the supercharger. Everyone knows warm air is less dense so starting with cooler air might have a little advantage even though we're then compressing it, which is also a process that generates heat. I'm not sure the results of this would be visible on a dyno even with fans blowing on the car compared to the air coming through the front of the car when it's underway. I also don't know how much of that air makes it up to and through the opening in the block off plate - seems like the more direct route would be straight through the radiator.
Reason #2 is that I wanted to enclose the filter to keep it cleaner and prevent it from getting wet when driving in the rain
My car drives very strong now, partly because of the intake (may not have made any difference), partly because I found where pressurized air from the supercharger was escaping, limiting my boost, and partly from the upgrades recently done to the Powerdyne unit itself by Carl.
As promised, I shrink wrapped my band clamps so they wouldn't stand out so much. I know it's a dumb reason, but I don't want to cringe whenever I look at my engine. Anyway blacked out looks much meaner and maybe more OEM-like.
Here's the pictures.
Take care.
Dave
Just for fun, I had a scrap of 3" OD tubing, which is the same size as the 928MS intake elbow. We know it performs well as delivered. I put that scrap on my intake, as seen it looks like a white circle. When viewed to scale, it gives me the assurance that my new dual intake should not be a restrictive element. It is also the exact size of each intake funnel.
Thanks,
Dave
03-14-2019, 09:20 PM
