Tom Cloutier

GlenL,

I think I agree with the intent of your statements, but not some of the details. This is sort of splitting hairs, but anytime you force a fluid (air, water, etc) through any sort of pipe, box, or even through a surrounding fluid, there is restriction to flow. Anything one does to reduce this restriction has the potential of improving performance. Whether the engine can make use of the increased flow is another matter.

A bone stock engine will probably not benefit much from improved intake airflow because of downstream restrictions such as valve size and timing and the exhaust system. Improving exhaust flow will likely allow the engine to ingest more air and anything one can do to facillitate that will probably improve performance. Just have to remember that an engine is a system, not an isolated collection of devices working indpendently.

Flow restriction is not an incremental phenomonon, but rather a continuous one. The more air you try to force through a pipe, the greater the restriction. It's not that at 340hp or whatever, the system suddenly becomes restrictive. The airflow was impeded as soon as you directed it through a pipe, but as demand for air mass increases, the limitations of the plumbing becomes more apparent.

In the case of my prototype dual TB intake, I did hundreds of dyno tests to arrive at this design and it is definitely not optimal, but did produce some nice performance improvements. At first, I utilized the stock TB and MAF in their stock locations while I experimented with numerous combinations of smaller throttle bodies mounted in various ways to the side plenums. I tried progressive linkages, solenoid-operated TB's, some that opened only at WOT, with and without the flappy, with Helmholtz resonator and without, and I found that all of this made little difference until I eliminated the stock TB altogether.

This led me to conclude that a major restriction to flow in the S4 intake system is that torturous toilet bowl-like passageway through the TB, into the resonator bowl and into the plenums. The next major restriction is probably the intake runners themselves, some of which have very tight curves. Anytime a fluid is forced to flow through a curved pipe, the flow rate is further degraded; the more curves and the tighter, the greater the flow restriction.

So we come to a near-optimal desigh like Louie Ott's monster intake. If you slap that beauty onto a stock engine, about all you will have is a car that runs lousy, but looks really pretty! So it's time to port the heads and install larger valves and longer duration and higher lift cams. Car still runs rotten. Oh now it's time for headers and freer flowing exhaust plumbing. It's almost endless!

Anyway, I know you already know this, but maybe it will be useful to someone somewhere!

Regards,

Tom Cloutier

GlenL

Tom,

You are fully correct!

I wasn't describing the constraints on the problem domain properly which was leaving the stock MAF, AFM or CIS body the stock airbox, filter and tubes working outwards from there.

Glen

Shark Attack

dido,, did i miss something on anoher post?.

Bill Ball

Somewhere it should be stated that this is for other twinscrew/roots blower installations like Gio and I have. This is not for flow increase - we need a cold air intake.

Alan

Shark Attack - I think we are beyond the "what is it phase" just read the rest of the posts....

Its a snorkel over the radiator to get cool air before the radiator and to find space for the stock filter (for a blower car). Its a work in progress - but shows all the basic construction ideas...

Bill the filter on the Koenig was very narrow - not much more than 1/2 the standard filter - I think Bill W said it was custom cut down to fit... On a TS there may be enough room for stock sized in the same place.

Would be nice to be able to use the stock filters... or at least commonly available ones.

Alan

Bill Ball

Thanks for adding that information, Alan. I didn't even get to look at Bill W's engine compartment. I was just going off photos. It would be nice if it could fit there and simplify the housing over the radiator.