mine is "magyvered"(sp?!) also ala 997 box with cut section on the drivers side. it used to accommodate a bmc oiled element but i ditched it in favor of the mahle paper. but i still "feel" faster for the increased air intake, along with the ipd plenum. at the very least, more air isn't "hurting, of that i am certain.

 

I always thought that dual set up could be good too, but if the stock box/filter design is quite efficient already then a twin setup like that would be more for looks then freeing up any restricted power.

 

Joseph,

Motor or transmission out makes it easier and that is how I did mine many years ago...however, we have had many people install it with the motor in the car - we even had someone do it in a garage without a lift (up on blocks), so anything is possible. I recommend doing it in conjunction with a motor out situation or clutch job.

Just like Powderhound, we made one additional cut on the passenger side to achieve a desired fit and that is very easily done. We ship our Hi-Flow Plenum/Hard Piping Kit with an "extra" silicon connector with two hose clamps in the event it is needed. It's not a big deal to make one more cut and join it.

The great thing is once our plenum is fit, you never have to do it again or worry about it failing. I have had more than one call from someone with soft piping that has failed and allowed debris to enter the intake track and damage the turbos and then they want the hard piping. Conversely, I have had occasion to remove my engine after roughly 100,000 miles of operation and upon inspection of the plastic tubing, it was found with no signs of wear damage anywhere...I don't ever worry about it. It is literally indestructible and as such, I feel it's the best product on the market for this application.

 

The Pork Hunt, here's a little data to back up the "airbox isn't the problem claim":





Courtesy of UMW. Blue is stock, red is 2.75" flex pipe. Hard piping will do better.



To each his own but I'd recommend against turning a fairly well engineered car into a one trick pony, at least on account of getting air to the turbos. Putting a pressure sink on the high pressure side of a duct system makes me cringe. BL, fenderwell intakes steal much needed airflow away from the intercoolers, and stealing is not cool Rough numbers on a 700 fwhp car (add power and it gets worse):

At WOT up to 50 mph: You have no airflow going over your intercoolers (!)
At WOT at 100 mph: Half of your would-be cooling air is not going to your intercoolers (a reduction in intercooler efficiency of approx 13%).
At WOT at 125 mph: Your intercoolers still are only seeing 66% of the air they'd normally see.
At WOT at 150 mph: You're up to 75%
At WOT at 185 mph: You're a touch over 80%.

Now you know why intercoolers that sit behind fenderwell intakes are typically the biggest heat sinks someone can shoehorn in there.

If you're skeptical over the math, here's some anecdotal evidence from Emre who beats the hell out of these cars, sometimes in very high ambient temps:

I've seen a few put the filters in the area between the intercooler ducts and the wheel well -maybe a good spot but still need to check the static pressure under WOT!

 

On the 996 box the cross section of the single rectangular cold air opening opening is greater than the cross section the the MAF inlet tube which is the limiting factor (restriction). Cutting an extra opening into the stock box does not remove the MAF restriction but only allows hot air to be ingested, unless you install another snorchel linking it with the deck lid. Having a GT2 style deck lid that provides a ram air effect to the air box would help but cutting another hole into the box or removing the whole back side certainly won't.

The 997 airbox had dual MAF outlets vs. a single one in the 996 box. As such it has dual snorchel air intakes vs one on the 996 box.

 

I wouldn't place the filter on top of the intercooler, there's room around the upper duct to fit piping and a filter. It's not high airflow but it's cool and up out of the way. I'm sorry I was unclear about that.

Chart is pretty and clearly shows replacing the stock tubing flows better, I agree rigid tubing would flow better than ribbed tubing. Guess what would happen with a straight filter or fender inlet? Likewise pressure drop would be lower although I'd expect some drop to remain even with straight filters - I'm told the space isn't large enough for a proper sized filter on the turbo. Where did the CFM figures come from and what level of power?

I'm curious as to why stock tubing shows greater heat - turbo ineffeciency or something else? Intake heat on my car hasn't been a problem so far, I've instrumented my intercoolers and see temps damn near ambient - stock air box and filter. We'll see how that goes with higher boost, warmer temps, and filters off the turbos.

Have no clue what Embre was trying to say with that formatting but I wasn't intending to place filters in the way of the intercoolers - that will remain sealed.

I find the numbers concerning airflow over the intercoolers pretty suspect though since air isn't forced over them but drawn from the bottom and even a filter on top of the intercooler can't stop this, where did they come from and how was this measured? I believe this isn't accurate as very little speed shows temp drop on my car and steady state cruise shows intercooler exit temps MATCHING ambient - I'm not running small intercoolers though so this might explain it? I look forward to datalogging IAT soon!

I'm considering adding scoops to the ducts to force air but have seen no instrumented testing yet. If I do it I may instrument the other intercooler so I can datalog it to prove airflow changes, current setup only shows intake, exit, and differential temps between the two on the intercooler. So far as I know no one else is doing these measurements but mine isn't currently datalogging so that's a bummer. I run hybrid k24 turbo too not k16.

 

Agreed. The aggravation in installing the Evoms piping is well worth it in the long run as it's the best solution on the market. The flex pipes have their drawbacks with durability and the aluminum piping will heat soak badly. I'm happy with mine even thought it sure would have been nicer if Evoms spent a little more time making better molds from the get go. It's pretty rare to get an OEM fit in the aftermarket so it's really no surprise.

 

I thought the same but i did some logging and there was no difference in temps with airbox on or off when the car is moving. Its the same as the intercoolers when the car is standing still they heat up but once moving they cool down.