Stock airbox intake flow (pics) - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Most_Wanted · 05-02-2019, 01:32 AM

During my research on a custom intake, i never did see a pic of the stock airbox opened. I heard how restrictive it was and wanted to see it for myself. It does look turbulent, as the air takes multiple turns before going through the maf.

Quadcammer · 05-02-2019, 03:09 AM

Stock airbox sucks and is barely adequate for 2.5l.

Jgkram · 05-02-2019, 03:55 PM

Thanks for posting this. A picture is worth 1000 words! Always wondered what one looked like on the inside.

Jgkram · 05-02-2019, 03:56 PM

Forgot to ask...so what’s your design for a custom intake look like?

KRAM36 · 05-02-2019, 04:16 PM

Put in a 987 air box.

987 v 986 Air box

maf and throttle body diameter

Jgkram · 05-02-2019, 04:43 PM

Gotta be something easier than doing that. Watched a few you tubes including Newart’s and man what a pain.

KRAM36 · 05-02-2019, 05:07 PM

Quote:

Originally Posted by Jgkram

Gotta be something easier than doing that. Watched a few you tubes including Newart’s and man what a pain.

Sure, if you don't want cold air induction.

Jgkram · 05-02-2019, 05:23 PM

Gotta agree with the King on this one. I’ve seen a couple of the fabspeed design mock up’s in our cars. Cleaner design, leaves A LOT more working room in the engine bay and it’s still a true cold air intake. Much easier than squeezing 10 lbs in a 5 lb bag.

KRAM36 · 05-02-2019, 05:55 PM

Quote:

Originally Posted by Jgkram

Gotta agree with the King on this one. I’ve seen a couple of the fabspeed design mock up’s in our cars. Cleaner design, leaves A LOT more working room in the engine bay and it’s still a true cold air intake. Much easier than squeezing 10 lbs in a 5 lb bag.

You will get more air with the kit FabSpeed offers, but it's not a cold air induction kit like the 987 air box is. For $400, not worth it to me.

https://www.fabspeed.com/porsche-986-boxster-evoms-v-flow-air-intake-system/

The 987 air box fits perfectly fine in the 986, you just have to move some stuff out of the way to get it in there. Is it easy to install, nope, but IMO, well worth the time and effort.

The Radium King · 05-02-2019, 05:05 PM

before it was figured out that the 987 airbox fit in the 986, i tried one of those carbon dynamic airboxes (cda) and just not enough room in there. about the only other valid solution i've seen is i think the fabspeed 987 solution that put an air filter in the gap between the rear quarter panel and the engine bay.

Jgkram · 05-03-2019, 03:26 AM

I have to agree that the 987 box is much better than the stock setup for sure. And you’d have to be an idiot or a billionaire to buy $400 - $800 worth of plastic/rubber tubing. However, I still see a lot of merit in the design. It’s simple, free flowing, utilizes a space that is protected from engine heat and readily available, lighter, etc. What I struggle with are the water entrainment issues. On most of my other cars the intakes are located in the front grill and direct the air (more or less) straight back to the throttle body in a very short distance. On the Boxster, while some water may enter the air duct, it would still have to get through a filter and travel you heck of a long way before reaching our throttle body. What am I missing?

The Radium King · 05-03-2019, 06:46 AM

well, $800 is stupid, but $400 not so much. you do a 987 airbox it will cost you $200 or so with txes and shipping, at which point you have to do a bunch of fabrication (time = $) and buy couplers, joiners, elbows, hose clamps, etc. i mean, the gas for the multiple trips to the post office/hardware store adds up, you know?

the water issue is a red herring. one guy on planet 9 installed one and drove it in a torrential rain and saturated the filter. became a big deal, impacted sales, so now vendors are trying to mitigate it. with my 987 air box, and the trimming i have done to the filter hanger, etc., there is a clear shot from my filter to the great outdoors (rain and all) and never had an issue.

otherwise, it is easy to fabricate and there is a how-to on this forum. a piece of lexan cut into a trapezoidal shape, a cone filter, and some silicone/couplers.

my review of it was this: resistance to airflow caused by the air filter is proportional to area; the larger the filter surface area the better (hence why the 987 air box is such an improvement over the 986 unit). measuring the inside of my fender well, there was no way i was going to fit a filter as big as the one in the 987 airbox.

Elmer · 05-03-2019, 06:47 AM

Just as a point of reference, I'm looking to revise the air intake for my 03 Boxster S. The Evo product looks pretty nice and would be easier to install. The 987 airbox makes sense, but is a bear to install. The price for either is about the same. For the 987 pieces, Ebay has them all, but it looks to be about $400 total, the airbox, tubes, throttle body and plenum. In my mind, the only reason to do either the Evo or 987 is to get the 74mm TB and greater airflow.

As to whether one or the other is a "true" cold air intake, the Evo looks to be sealed around its perimeter, and the 987 box is self contained. Both draw from the same source. Is one significantly warmer than the other? Dyno charts for both are about the same. Fabspeed published dyno runs for incrementally modified 986s. Eventually they ended up at the Evo airbox, full exhaust system and their ECU tune. I believe the final increase was 27-30 hp above base.

KRAM36 · 05-03-2019, 07:14 AM

Quote:

Originally Posted by Elmer

Just as a point of reference, I'm looking to revise the air intake for my 03 Boxster S. The Evo product looks pretty nice and would be easier to install. The 987 airbox makes sense, but is a bear to install. The price for either is about the same. For the 987 pieces, Ebay has them all, but it looks to be about $400 total, the airbox, tubes, throttle body and plenum. In my mind, the only reason to do either the Evo or 987 is to get the 74mm TB and greater airflow.

As to whether one or the other is a "true" cold air intake, the Evo looks to be sealed around its perimeter, and the 987 box is self contained. Both draw from the same source. Is one significantly warmer than the other? Dyno charts for both are about the same. Fabspeed published dyno runs for incrementally modified 986s. Eventually they ended up at the Evo airbox, full exhaust system and their ECU tune. I believe the final increase was 27-30 hp above base.

If you think that EVO air box is sealed, you're sadly mistaken. You are correct, if you're going to do the air box, you should do the full intake system, including the larger throttle body and intake pipping. I would say on a 986 3.2 engine, just doing that you're looking at around 18 HP gain. I don't have a tune on my car, but with my mods, I'm getting around a 30 HP increase.

Quote:

Originally Posted by The Radium King

the water issue is a red herring. one guy on planet 9 installed one and drove it in a torrential rain and saturated the filter. became a big deal, impacted sales, so now vendors are trying to mitigate it. with my 987 air box, and the trimming i have done to the filter hanger, etc., there is a clear shot from my filter to the great outdoors (rain and all) and never had an issue.

Your 987 air filter is much larger and would not be saturated by water as easily as the smaller air filter on that $400 kit, plus the 987 air box has the filter inside the air box and not sitting right in the smaller vent area of a 986 like the $400 kit. I waited 2 years to clean my K&N air filter and when I pulled it out, there was plenty off clean area on the filter as to not starve the engine for air. After cleaning it, I didn't even notice a difference. There are trade offs going either way, if you never drive in the rain, then that $400 kit would be a decent upgrade, but if you want the best all around air box for the 986, put in the 987 air box. Yes it's more labor intensive, but worth it IMO. I'm still scratching my head why anyone would put the $400 kit on a 987.

Most_Wanted · 05-03-2019, 08:29 PM

I would have went 987 airbox but the difficulty in fitting one in swayed me away.

I'm still working on my new setup but for now its an aluminum airbox with a cone filter inside, a snorkel attached on the outlet, fed to the side vent. I cut off the snorkel piece on the stock airbox and used it as a block off plate and used foam tape to seal any possible gaps.

So far I've been seeing 20F above ambient(60F average days) in city and 5-10F on hwy.

My mods now are 3 inch intake tubing(airbox inlet/outlet is 4inch) 997 throttle body and plenum. Headers and catback.

SpIcEz · 02-13-2020, 04:36 AM

Just thought Id throw a wrench into this old thread

https://www.youtube.com/watch?v=l1Volf_rp_I

https://www.fabspeed.com/porsche-986-boxster-competition-air-intake-system/

tommy583 · 02-13-2020, 06:58 AM

That basically looks like the EVO intake Fabspeed used to sell, only now more expensive. It still doesn't seal the engine bay from the filter section. That rubber on the top edge is below where the top cover will be, it will never seal like that. Why can't they just make it a sealed box with some kind of air tight door to service the filter? Why does it have to cost so much? I mean really $500 for a piece of metal, a foot of plastic tube and a cone filter.

SpIcEz · 02-13-2020, 09:57 AM

Quote:

Originally Posted by tommy583

That basically looks like the EVO intake Fabspeed used to sell, only now more expensive. It still doesn't seal the engine bay from the filter section. That rubber on the top edge is below where the top cover will be, it will never seal like that. Why can't they just make it a sealed box with some kind of air tight door to service the filter? Why does it have to cost so much? I mean really $500 for a piece of metal, a foot of plastic tube and a cone filter.

I agree the price is quite outrageous.

As for sealing, I dont think its a problem. If you find it doesnt seat well, you could add foam or something else under the rubber seal to make it tighter.

But, honestly, to me it just demonstrates all the naysayers saying you NEED a stock airbox to make power are saying nonsense.

There is nothing magical about their design. And the M96 works just like 100% of all engines out there. Less restriction = more power.

They show considerable gains on that dyno. Now, on the other hand, I'm sure you wont get that in all conditions. Especially on a hot day when things are heat soaked.

I can build one like that, only thing is to find a MAF flange for 986/996 MAF sensor to weld on a suitable aluminium pipe.

Tremonte986 · 02-13-2020, 02:16 PM

Quote:

Originally Posted by SpIcEz

I agree the price is quite outrageous.

I can build one like that, only thing is to find a MAF flange for 986/996 MAF sensor to weld on a suitable aluminium pipe.

EZ-PZ....

https://shop.advanceautoparts.com/p/spectre-mass-air-flow-sensor-adapter-87051/11430025-p?c3ch=PLA&c3nid=11430025-P&adtype=pla_with_promotion&product_channel=online&store_code=&gclid=CjwKCAiAhJTyBRAvEiwAln2qB3I459So1fmiJ8C87j9N 4NnnrZZOKqzM7L05jwpSLgje1VT4aKsCthoCx4MQAvD_BwE&gclsrc=aw.ds

You can get MAF housings cheap. Bolt on plastic configuration, or the aluminum like above.

Topless · 02-13-2020, 07:33 PM

It's easy to overthink this stuff and get sucked into the marketing hype vortex.

Back in 2005 there was a lot of independent dyno testing going on to compare different intake airbox designs. The airbox should do 2 things well: Let plenty of cold air in while keeping the hot air and bad stuff out. As I recall these were the basic results after a LOT of testing:

Stock 986 airbox worked fine on a 2.5L

987 airbox added 1-2hp primarily on 3.2L models

Cone style EVO filter inside the engine compartment lost 2-3hp due to higher intake temps, and rapid oiling of the MAF sensor caused the engine to run poorly. It was discontinued.

Boxster Spec Race cars all run stock 986 box and (I think) stock paper filters.