Cupcar#12

lalala.... This has been discussed alot before of course.

I would be interested in seeing the Dyno graphs

i am going to do some dyno work soon, and plan to test this out

etom

So what is this stuff Fabspeed says about their open-style set up? It seems to be, more or less, just an opened back, and they claim +8HP gain? Here is their info:

964 CUP High Performance Air Intake System $175
All 964 C2/C4/RS America products 1989-1994
+8HP on 964/C2/C4/Carrera Cup/RS America
Fabspeed Motorsport Cup hi-performance air box works with your stock OEM air box. You simply remove your stock air box cover lid and reuse your stock air filter or K&N air filter and clip on the Fabspeed CUP replacement OPEN airbox coverlid.
Simple and easy installation in less than 10 minutes
Most cost effective and simplest air intake modification.
More power and sports car sound with improved throttle response.
Fabspeed added rain shields and other airflow refinements to maximize performance.

Red rooster

Wow , this is still happening . If you do a dyno test be very sure to have an accurate , fast temp gauge in the box behind the filter element . Thats to allow the operator to use a dedicated fan to hold the intake temp constant.
Without that ,the whole test is pointless !

Chassis dynos are notorious for generating 911 intake air temp variations so confusing results . Sad old business isnt it !

Good luck to both camps of opinion .

Geoff

Andy Roe

I fitted a drilled cover to my first 964. Didn't notice any difference in performance, just more noise (some bad resonance higher up the rev range too). On my second 964 I decided to try fitting a cover with the whole front of it cut away (like the Fabspeed box, but I instead invested in a used stock cover for about £30 from ebay and a hacksaw to save some cash!). Again, I couldn't feel any difference in performance, just more noise. No resonance though this time.

I have since put it back to stock as I prefer the exhaust note with just a CAT bypass & cup pipe fitted and the extra intake noise from the drilled/cut airbox cover IMHO, spoiled it somewhat!!

zicoramone

Try it and you will see...it's by far the best bang for the buck mod. period.

Jay H

Racing is a different animal, so my post only applies to street cars. Note where the "horn" on the air box terminates when the engine lid is closed. It's pulling cool air right from the engine lid grill. By drilling your air box on a 964 or 3.2 liter car, you're no longer taking advantage of pulling cool air from the engine grill/outside the car. As mentioned, hotter air reduces power and a drilled 'box can pull warmer air from the engine compartment in certain situations.

Porsche would never leave 8 horsepower on the table unless there were some severe disadvantages.

SimonExtreme

I have and can report no difference! There might be 1 or 2 bhp at the top end, but the difference is within the statistical "noise" of dyno tests so nothing provable at all.

In addition, I personally think the car sounds better without the holes.

N51

I've the cupbox, cup bypass, and cat bypass. Great noise, but I miss the whirl of the valvetrain.

Noah