Intake plenum and 911 throttle body

[Ben006]

If you use a 15 degree 3" tube, you need a slightly less than 90 degree coupler for the TB.
A 90degree coupler cut slightly shorter works fine.
I'll post pictures tonight!

Gelbster, you mean an air filter where the snorkle is usually ?

[Gelbster]

Originally Posted by Ben006

Gelbster, you mean an air filter where the snorkle is usually ?

Yes Ben,
I cobbled together an experimental air filter from "UNI" foam and fitted it in the 'tunnel' where the snorkel usually is.It fits behind and is attached to the louvers.One screw and it all slides out.
The use of the tunnel as an air filter housing enables a very compact new arrangement in the engine bay where the old airbox was. Access to the Bank 2 - 4,5,6 inlet manifold area is now excellent from above.
The concept needs proving. And improving. I am (wildly)guessing that I have an acceptable compromise of filtration vs. obstruction.
I also fitted a finer mesh screen(like the997 has) .I also fitted an airflow straightener before the MAF. Who knows if .....
The project was not planed.I had to r&r # 4 injector and the fuel pressure regulator. Try that with the engine and airbox in place and you'll understand.
I am not advocating this as an effective project because I do not have test data.

[Ben006]

Originally Posted by Gelbster

Yes Ben,
I cobbled together an experimental air filter from "UNI" foam and fitted it in the 'tunnel' where the snorkel usually is.It fits behind and is attached to the louvers.One screw and it all slides out.
The use of the tunnel as an air filter housing enables a very compact new arrangement in the engine bay where the old airbox was. Access to the Bank 2 - 4,5,6 inlet manifold area is now excellent from above.
The concept needs proving. And improving. I am (wildly)guessing that I have an acceptable compromise of filtration vs. obstruction.
I also fitted a finer mesh screen(like the997 has) .I also fitted an airflow straightener before the MAF. Who knows if .....
The project was not planed.I had to r&r # 4 injector and the fuel pressure regulator. Try that with the engine and airbox in place and you'll understand.
I am not advocating this as an effective project because I do not have test data.

I'll take a look at the possibilities when I have the time



The first sold plenum is ready !




You'll notice the four ribs added. Just for security and further stiffening!
You'll also notice that my masking tape game is not the best one yet... ^^

I ordered a 996 plenum too.
I have a GT3 throttle body at home and a guinea pig who's willing to test it on his 996

Ben

[Ben006]

[Ben006]

Oh, what's that???


Looks like a GT3 TB

[CrisZenithBlue]

cant wait to get in on this action as soon as i finish with maintenance expenses! nothing like a more linear powerband with more usable low end grunt. coming from the honda S2000 i can say i miss the vtec kick at 5500RPM which was pretty damn cool but the reality is you dont get much of that daily driving.

when i met Ben a while back and drove his boxster i could REALLY feel the difference in the powerband and it felt so right, like it was supposed to be like that from factory. i personally like the max power output of the base boxster, it doesnt get you in guaranteed "jail time" speed right away, the only thing i would change is how that power is delivered.

good thing there's guys like Ben making this stuff happen!

[l3m]

I'm selling a 997 throttle body, 997 plenum and misc. hardware. It's listed in the Boxster Parts for Sale section.

[geetee]

how much is this plenum?

[particlewave]

Aluminum conducts heat very well and turns all your hard work into a hot air intake, probably negating any possible benefits from the plenum. You'd be much better off with a plastic tube with heat shielding.

[Gelbster]

This Plenum is plastic !
Agreed for conductive heat ,but the heat source in this case is radiated and convective,not much conducted because of the' rubber' boots. Which is why polished aluminum or 'chrome' coated ABS are usually used for commercial CAI systems. Spectre products has more info. Heat reflective tape may help ? The air charge in the CAI tube moves fast enough that it won't have time to absorb much excessive heat. Hot-Idling/Dyno would be a problem because of heat soak.
But some Track time would be more valuable than my theorizing.

[eddy]

The DEI gold reflective tape works great. I used it on the engine bay side of a custom airbox in my SCCA ITS Miata (the box was made from sheetmetal) along with some thin silver duct insulation on the filter side. temps were near ambient as a result.

[Gelbster]

Agreed but use ALuminum/chrome on a Porsche - gold is soooo Ricer !

[eddy]

It does have greater reflective properties than silver, plus with the race car it was on i wasn't headed to the local cars n coffee our two thread conversations are a welcome distraction from the spreadsheet i should be working on!

[Ben006]

I don't think you'll feel a difference with reflective tape on the boxster, but for the price... you might try!

I put some on the first version of the plenum.

I feel that the 986 is really sensitive to outside air temp, I can feel a difference between morning power and noon power, even though it's only 10/15°F difference.
I think it has more to do with the ECU settings that advance timing when it gets hot than the actual difference in air density...
I got a new phone so I'll be able to do datalogging easily now. I'll try to collect the right info, see what's really going on!

[Ben006]

Soooo this week end I had a ton of things to do... so I decided to do something else!

I received the 996 plenum, so I made my version for the GT3 Throttle body, fairly easy since it's a straight T!



Due to its symmetrical shape, I made radial stiffening ribs (like the OEM cross over pipe)... And I really liked it!

So I tried on the 986 plenum... due to the non-symmetrical shape... it took me all afternoon...
But how cool is that!





I really like it!
It's also probably a lot stiffer... but also more expensive and a ******************** to paint...


Ben

[Nine8Six]

This is some nice work Ben.

How is this comparable to the stock unit airflow-wise? Bigger means better in this case?

Still waiting for the 2.5 power kit, i.e. the car that needs it most imo lolll

[Ben006]

Thanks

Smoother bends than the original plenum, and bigger throttle body, and yes, bigger is better on this area! The only compromise is noise. A bigger throttle body is noisier (air noises). But really, you don't notice it.

The problem with the 2.5 is: where to find a bigger throttle body? A 993 TB? Or an aftermarket one?
The plenum has the same shape as the 996 plenum, straight T, so it'll be pretty easy to make.
Thought, it is bigger than an "e-gas car" plenum, so it would be more expensive!
If someone want's to be a guinea pig, I'll be happy to work with him!

[Meir]

Or get one of these

OBX Individual Throttle Body ITB Fits Watercooled Porsche 911 Boxster | eBay
:dance::dance::dance:

And just to be clear. I'm first in line for the 996 plenum.

[edc]

For a mechanical body 2.5 the upgrade path is the mechanical body 996 3.4.

[madmodz]

Well I was ready to go back to oem configuration because my car didn't run right. Couldn't clear a misfire to cylinder 6 code after changing everything. My screwup. I switched the fuel injector wire with one of vacumm plugins so they look the same. Best news I had all year! So tomorrow I will rebuild her.