drhendrix

I suppose my point that a lot of what you said isn't quite right. The main statement that you made that took me by surprise was that a adding a freer flowing exhaust system would not result in a net increase in engine hp, but only more torque to the rear wheels.

I guess my point is that you CAN increase the hp output of your 997 engine by simply bolting on an exhaust system that flows more freely.

993C4

I think we're somewhat deviating away from the topic.

I'm not so much interested in power gains, but rather, improving the induction sound of the 997S, which the PSE doesn't do. PSE enhances the exhaust note, and no complains here. What's lacking in the 997S is the classic 911 throaty burble from the air box intake. Those of you've driven or own the 964 and 993 will know what I'm talking about..... drill some holes in the intake box and you get this glorious orgasmic burble.....

Anyway, I checked with my dealer and since my car is so new, I'm not willing to take any risk with aftermarket parts for now, because if anything goes wrong (buggered MAF perhaps?), it will void my warranty. I guess this is good way of staying clear from that slippery slope..... so for now, I'll just have to enjoy my PSE sound.

Happy and safe driving rennlisters

OCBen

Orgasms??? ... Yeeahhhh, I'd say we've deviated wayyyyyy off topic here.

drhendrix

As long as we're way off topic on this thread, I've been mulling over for weeks ever since I bought my 997; how to cure my S envy? Any non-S 997 guys out there want to chime in? Would software, exhaust, and intake cure it? Bigger brakes? Headers and cats too? A supercharger?

Or the ultimate poser, just go out and buy an S badge and quad tips

Help me I'm desperate.

And I was hoping that buying a Porsche rid me of this insatiable need to mod every sports car that I own.

Rolf Stumberger

drhendrix
At the risk of belaboring the point, I will stand by what I said above.
I think you are confusing an engine producing more HP with having more of the engine HP available at the driven wheel.
Let me try a "general" simple example :
Lets suppose an engine produces 355 HP (at full throttle )
Lets also suppose that 20 of those 355 HP is needed to suck air thru the intake filter and to expel the combustion products out thru the exhaust system ( mufflers,cats etc. )
That leaves 335 HP available to drive the rear wheel . OK?

Now lets remove the air intake filter and the entire exhaust system .

Have you just increased the HP the engine produces ?
NO. But you have made 20 HP more available at the driven wheel .

If you want to increase engine HP , you can only do so by giving it more fuel/air to burn . And since the Porsche boys have decided for us what that maximum is, you can only override it by removing the factory chip ( which limits the fuel flow etc. )and replace it with an aftermarket so called "Powerchip"??
In which case you probably will void the factory warranty .

To summarize:
If you really want to increase the HP an engine produces you will need to give it more fuel to burn, which will require more combustion air ( via tubo or supercharger )and changing fuel injectors etc.

And then ,if you want maximum torque at the driven wheel, where it counts, remove all HP robbing obstructions, such as Mufflers etc.

PS: Does the dr in front of hendrix stand for Doctor by chance?
( I only have a PE behind my Mech. Eng. degree) Lol

Rolf Stumberger

993C4
You do not need to drill some holes in the intake box.
They are already there ( at the filterinlet side)
The reason , I suspect is not however to give you an " orgasmic burble" but to keep the box from blowing apart in case the engine backfires ??
(But I could be wrong) Lol
Some people also add a pressure relief flapper on the filter outlet side to further ensure the longevity of the expensive box .
( But the flapper is normally closed so as not to let any dirty air in and therefore will not add to your "sound " experience )

OCBen

Wrong! ... Sorry.

If an engine "produces" 355 hp, that is a net power output figure, after every subsystem drain and contribution has been taken into account. The only question is where the output is being measured - at the flywheel or at the drivewheels (dynamometer). If measured at the drivewheels, multiply that hp reading by the reciprocal of the mechanical efficiency of the drivetrain (assuming it can be ascertained accurately, ~ 80-90% at best) to arrive at the net hp output of the engine at the flywheel.

drhendrix

OK, I think I am understanding your confusion. Your point is that Porsche has programmed the software to provide a specific amount of fuel and that no matter what you do to the air flow, you will have no more fuel to burn.

The truth however is that all these modern cars measure the intake air flux and can adjust the fuel flow to match up to a point, so that without software modifications, you can get gains with bolt ons. To get even better gains, you must modify the software to match the new configuration.

Yes, the dr stands for Dr. PhD Astrophysics Glad to see a fellow scientist type on the board !

Rolf Stumberger

Nice to meet you Dr.Hendrix
I think we had fruit as the subject matter , with you talking about apples and I about pears Lol.

Anyway , if you're ever in the N.J. area , maybe we can get together . I never could fully grasp that quantum physics stuff.

kkswow12

what am I looking at here? is this a real 'thing' in the filter box or someones exercise in leg pulling? don't know how I came upon it but would like to know more...anyone?

jhbrennan

For sure on the 997.1, don't know about the 997.2. IIRC, the whole purpose of the Fabspeed "Orange Cap" was to get rid of the Helmholz resonator.

kkswow12

but with the X51 is there something else to look at or is this taken care of...just hard to envision what's going on here

wc11

I've got it installed and the sound is noticeable because it bypasses the resonator.
The gurgling is heard when you first start it up.