Louie928

Good observation Jim. This certainly looks nice. I do wonder about the effective filter area though. The stock 928 air filter has about 80 sq in and I can't see more than 35 sq in effective area on this. The radiator can be lowered for more space above it and maybe that's what's been done. The power of the pump is amazing though and with enough pressure differential across the filter I'm sure would flow enough air to support nice power. The dyno will tell. A set of runs both with, and without, the filter element would answer any questions about the size.

Carl Fausett

You'd be amazed how expensive that air filter cabinet has been to manufacture.
But, I was commited to it because I wanted a presentation piece with high curb appeal to top off our 928 supercharger kits.

Now that the prototyping is done, I am back at my sub-contractors to get them to sharpen their pencils in quantity. So, I do not know yet what the production cost will be for that part, but it'll be lower than what I paid!

Sure, I can offer it as an ala-carte item. Tass - I did figure that owners of my earlier kits would see it and go "I want that!" so I designed it in such a away that they could get it as an add-on to their SC kits. No problem, I can add it to your kit as soon as I know the $$ numbers.

As to PMotts question: I agree in the first 1000 miles, that filter medium too the far end really won't do much, you are right. But, after the filter directly in front of the air inlet gets dirty and more restrictive, the air flow is at least allowed to the side of that. The design is meant to increase service intervals for the air filter. Secondly - relative to curb-appeal, I also thought that if the filter was just in front of the inlet only, it would lack symmetry and not look as nice.

As to the following questions:
This is meant to be a Stage 1 kit. Easy install, very tame, very safe. Stock injectors, no fuel mapping needed, no EZK adjustments needed. We do retard the timing about 5 degrees for added safety. This kit is very low-tech and straight-forward, although the head unit itself is quite modern.

This is the first all-new centrifugal supercharger to be drawn-up from a blank sheet of paper engineered in over 20 years, the first centrifugal supercharger to adopt ceramic coated impeller from the Turbo industry, and the first supercharger to air-cool the bearings rather than hot oil cool them.

Carl Fausett

The size of an air filter has more to do with its service interval than its restriction. At the point that the air filter is at least the same size as the intake, it is no longer restrictive (other than the restriction caused by the filter media iteself, which I am not talking about in this post).

I could cover a 3" inlet with a 4" x 4" square of gauze and it would not be restrictive. But, it would need to be cleaned or replaced in a very short while.
The large air filter Porsche designed into the 928 was not based on what the engine needed. It was designed to meet the tune-up service interval they were wanted.

Other examples from automotive history: The Ferrari GT air filter, the Hemi Cuda air Filter, the Road Runner 440 ci air filter, the Olds 442 with dual 4Brl carbs, and a lot more. The air filters in these were less than 2" high (1.75" to be exact), and wrapped around the dual 4Brl carbs in a big oval. Restrictive? Not when they were clean. But they needed to BE cleaned often, because they were smallish, they got dirty fast.

Abby Normal

What psi is the boost of the standard kit?

You've got my attention! When will these kits be ready for purchase/delivery?

Louie928

Thanks for the explanation Carl. I see your point. I notice on my engine, which uses a stock 928 size filter that, compared to no filter, I lose 10 hp with a new Porsche paper filter, and 5 hp with a new K&N. For me, the ~80 sq in Porsche filter size is marginal disregarding the maint interval. I inferrred from that, that the size (area) of the filter, as well as the filter medium, made some difference in performance. I only have 1 bar pressure to work with and no pump to help out so maybe more of a factor.

j.kenzie@sbcglobal.net

Carl,
Looks great! How tough would it be to adapt to 16V L-jet?

Carl Fausett

Abby - we are taking orders for this kit as soon as : 1) I get documentable (dyno) results, and 2) I get the website corrected. Right now the kit for the 85/86 is too expensive and it shows a Powerdyne unit. We like this Raptor much better, and the Powerdyne kit for this year is being dropped.
If you want to see it, click here:
http://www.928motorsports.com/parts/32vstage1.php
What does this mean? I believe I will have those 2 things done and be taking orders for it in 3 weeks or less.

J-Kenzie - we have both a Stage 1 and a Stage 2 kit for the L-Jet 928 now. Many satisfied customers for it. If you want to see it, click here:

Stage 1 L-Jet kit: http://www.928motorsports.com/parts/stage1.php

Stage 2 L-Jet kit: http://www.928motorsports.com/parts/stage2.php

As always, thank you for your comments and your interest.

backnblack

Nice work Carl , Merry Christmas

Kevin Michael

Is this Tim's development or Carl's?

largecar379

Carl:

suggestions for this awesome looking air filter box:

adjust the right upper blower support to allow a twin (Y) intake hose.

in other words, from the blower intake, utilize a Y (it may need to have an upward turn on the blower end) and then plumb the two intake pipes to your air box, similar to the factory upper radiator support "intakes". You could still use the air filter pictured, assuming it has enough square inches area for sufficient flow to the blower's needs, except you would now have two inlets from the air box.

It very difficult for me to see (in your pictures) the clearances involved (upper blower support/upper radiator hose), but if there is enough room to do this I believe you would create less restriction to the blower and it would be more visually balanced.

??????

A great product from Carl.......again!

(Geeez, I want one of those for my hybrid.....)

--Russ

Tim Murphy

This kit is all Carl's. He developed it from the ground up and congrats to him for doing so. Putting together a complete aftermarket performance kit such as this is not an easy task and anyone who has ever attempted to do so knows exactly what I mean.

Good job Carl and Merry Christmas to all of you!

Carl Fausett

Thank you, Tim.

Russ - boy - did we ever try a dual-air intake for the 928 to our air filter assembly. Worked at it hard for a long time. There is just too much going on there to get it in... the upper radiator hose on the right side, the thermostat casting at the rear and left sides, the throttle cable assembly left side (85/86), and the supercharger outlet tubing itself.

The twin tube intake became so small to make it fit it was restrictive and I abandoned it for the large single tube - uncompromised, and a solid 3.0" all the may through. Form followed function on this air intake design.

MGW-Fla

Congrats Carl! That looks very nice. Can't wait to see your dyno #s too. You've had a busy and successful 928 year to say the least!

James-man

For the balanced look, you can put in a falsie. Except for, what I am guessing is a blow off valve near the driver side-back of the engine, you can easily run another line that does nothing but balance the look.

Imo000

Nope, it's to control fuel pressure on and off boost.