Eli K

Saw this going on e-bay for about 1/2 the price performanceparts charges for the K&N set up. Curious what you guys think, or if you had any experience with the part. To me this beats drilling holes in the airbox....and frees up some room under the hood...


Intake on Ebay

way too cheap to be good....

Bill Gregory

The difficulty with that type of setup is that it has more opportunity to pull in hotter air from the back of the compartment,which isn't helpful to developing power. With that shield in place, it almost guarantees pulling in hotter air. While there's some active discussion on whether K&N-style filters really do anything, if you're going to replace the stock setup, at least get one that uses the curved piping to place the filter closer to where, at speed, the air enters the engine compartment.

Julian Thompson

I'm afraid I'm with Bill on this one. Firstly the aluminium is a dreadful material for an intake as it holds heat so well compared to the stock plastic one. Secondly, you've got to remember that the air flow flapper door is a much bigger restriction than the filter itself anyway, and since a chain is only as strong as its weakest link you are not going to improve things this way.

You will, obviously, get some nice noise by opening up the intake like this but just don't expect more power!! (I would say the best bet would be to design a new airbox that takes cold air from the spoiler directly.....)

Eli K

Good call! Before I try to desing my own, are there any alternatives already in existance?

Julian Thompson

Yes, there is an absolutely GORGEOUS carbon fibre system made by GRUPPE M. It is a little pricey IIRC but looks just stunning! I have seen their work before and I have to say it is without equal.

Cupcar#12

I had a K&N filter installed w/o that huge water shield (you should not need it)
the performance gains were non-existant on a dyno. (and only 3-4 HP out of the B&B full system that was also installed) we did test with the stock air box cut as per the orignal Cup series modification. This was actually were the gains were (2HP). As pointned out above the Air flow sensor is the restriction point in the system and induces turbulance into the intake track.
The K&N intake sounds good however but i would not put any faith in the HP gains.
your miliage may differ and all of this testing was done on a 92' cup car (blueprinted motor, motorsports chip, etc. so it was pretty dialed before these mod's)

Tom W

Rob, what kind of hp do you get at the rear wheels with the cup car?

Oddjob

Rob,

The K&N setup had no hp gain over the cup airbox (cutout), or over a stock/street airbox? And the cup cutout box had 2hp over a stock/street box?

Thanks.

Cupcar#12

no gain over the cut air box - actually 1-2 HO less than the cut airbox. I did not test with the stock un-cut air box in place. I was about 248 at the wheels - with a 15% correction should be near 285 at the flywheel. the following items were on the car however
Cup Bypass, Cat delete, Andial PMNA 92 series chip, RS .00 DME (stock for the cup car), stock headers, fuel mix was normally 5 gallons of 100 No-lead - topped up with 92 octane & of course the blueprinted motor with sealed cams. This was my final configuration for the 03 one lap W/ the addition of the Ti final exhaust which was a straight through design, i also had to move to a different chip (Weltmister) to cope with the random gas on the highways. no testing was done with these in place however.
Honestly i believe all the gains were made in the motor over the stock 964 mill, the exhaust and intake gains were minimal. the tolerences were much tighter than the stock motor and as it aged (miles) it felt stronger. I will be doing a full series of dyno's when the car comes back together - in stock and then a yet to be decided upon modified engine spec.
please bear in mind that this is an apples to oranges comparison b/c of the blueprinting.

tonytaylor

Rob, do you think the differences in HP are due to the blueprinting and not the RS DME?

Cupcar#12

un-known really - the RS DME has much more advanced timing curves than stock since it was tuned to run only on Race gas basically. This is an american series unit so i do not know the maps exactly.
The best bang for the buck IMHO
one of Steve Weir (Rennsport Systems) custom chips to match your engine mods light weigh flywheel, cup bypass, cat delete, etc
- the Cup primary muffler bypass, cat delete and cut the air box (30mm from the mating flange all the way around)

tonytaylor

Agree re: the custom chip with mods as described.
My own (custom) chip runs more advanced timing curves ( witness recent engine running backwards) and hp at least matches RS equivilants.

I'm just a little sceptical about the superiority of the RS blueprinted motor.

Cupcar#12

porsche Dyno'd these motors at 271 +/- 1 HP at the factory that was at the flywheel. Cat Cup bypass, and G-Pipe(?) (the porsche version), cut air box, RS DME. they listed these as "engine modified and sealed"
I cannot explain why my engine posted the numbers it did other than it was well broken in, possibly the fuel mix is responsible. Or it could be Down on HP compaired to the others.
At this point i don't know and have no way to verify (the car is in intensive car right now and engine is about 3000 miles from the chassis). Generally when an engine is blue printed the tolerances are much tighter, all moving parts are weight matched, etc. porsche had the ability to pick the parts which goes into each and every cup car individually. like any engine they tend to get more powerful as they put on loosen up, to a point, then they need freshining.

In Mark Donahue's book "the unfair advantage" they regularly would break in a brand new race motor - take it apart and remeasure everything - making sure it is at the tolerences that Traco origanlly set, reassemble and run it. they found this normally increased the power of the motor.
Basically for a street car this is totally unnessecary and extemly expensive. for a race car you look for every last advaiable HP within the rules. if blueprinting will gain you 5-10-? it's worth the effort.

Dunasso

Don't know if it was mentioned but the stock air box has a velosity stack built into it which makes it more desirable over the K&N type cone filter setup. Also the stock box brings in cooler air. The only real atvantage to a cone filter would if you changed the MAF to a hotwire and could then find some ductwork to vent the cone breather somewhere cooler that the engine compartment. Otherwise those things add no sugnificnt advantage to your performance, but they do look cool.

914und993

I'm going to stir the pot here a little bit. I'll start by saying I am no fan at all of K&N intake assemblies on the 964/993 and don't believe any of these types of "upgrades" offer a genuine performance increase with a stock engine. However, I don't really believe the argument that they reduce performance by allowing more hot air into the intake charge. Actually they do, but I suspect it is an almost infinitesimal effect.

Think about the amount of air coming into the engine compartment when the engine is just starting to get wound up. At 3600 rpm (to make calculations easier) the engine is spinning 60 rotations per second. Each cylinder pulls in an intake charge every other revolution, so the air flow into the engine is 30 X 3.6 liters, or 108 liters per second. That is a lot of air. How much heat do you think the top of the engine, which isn't even that hot, can transfer to 108 liters of air in one second? That doesn't even take into consideration the additional fresh air being pulled into the area by the engine cooling fan, and directed into the area by a raised spoiler at speed - no doubt a far, far greater volume than 108 liters/second though I don't have any way to make that calculation.

Just something to think about.

Chip