home made true cold air intake

[Boxtaboy]

I've seen someone jury rig a plexiglass cover on an EVO intake, which at least seals off the area, but that one above is a hot air intake!

[Gelbster]

Note what Mr.Particle said in #19. He is one of the smart guys on the Forum -for the noobs.
We need to do better.
It is bad enough that the stock airbox gets hacked out but to then spend time and money installing an inferior diy hack is just too Ricer for the 986 Forum - I hope.

The solution I suggested may be imperfect but at least it is cool .O.K. not cold but probably not much over ambient temperature.
The plan is -create an airbox and filter within the empty cavity between the inner and outer fender walls.
The stock system uses this route.It just does not use the empty space there effectively.
If anyone has a better alternative for CAI,please share. I have no pride attached to the 'fender void' suggestion.

[Gelbster]

Originally Posted by particlewave

That's a hot air intake.

You should try to go back to stock. Your car will be happier.

Agreed.
But reinstalling an airbox? I would love to see the diy on that !
I am working in that area at the moment and the amount of dismantling of difficult items is awful.Engine out - no problem .

[particlewave]

I was mostly referring to Xpit's K&N setup. Nothing but hot air there.
The OP's isn't bad, but a bit of a hack job and seems like a lot of work for something that may not even be marginally better than stock.

Even the best intake plenum systems out there are questionable in regards to benefits.

But, yeah...Xpit has a hot air intake.

[The Radium King]

Originally Posted by Gelbster

Note what Mr.Particle said in #19. He is one of the smart guys on the Forum -for the noobs.
We need to do better.
It is bad enough that the stock airbox gets hacked out but to then spend time and money installing an inferior diy hack is just too Ricer for the 986 Forum - I hope.

The solution I suggested may be imperfect but at least it is cool .O.K. not cold but probably not much over ambient temperature.
The plan is -create an airbox and filter withing the empty cavity between the inner and outer fender walls.
The stock system uses this route.It just does not use the empty space there effectively.
If anyone has a better alternative for CAI,please share. I have no pride attached to the 'fender void' suggestion.

already done - fabspeed make one for the cayman.

Fabspeed Comp Intake 987.2 Boxster/Cayman

[Gelbster]

Originally Posted by The Radium King

already done - fabspeed make one for the cayman.

Fabspeed Comp Intake 987.2 Boxster/Cayman

Thanks for the interesting link your Radium Highness. .
Fabspeed stole my idea ;-) .But did not finish the task.
Seriously, does it fit the 986?
It looks like it is too large in diameter for the stock(salvaged) MAF tube and the rest of the reused intake ducting..
I see where the Fabspeed design inspired the OP. Surprising he did not disclose the source of inspiration. Perhaps he was robbed also!
I note that Fabspeed do not excavate more space from the void between the inner/outer fender walls to give the filter a plenum to work in. The filter pictured would be jammed up against the walls of the stock cavity in the 986. Maybe there is already more space in the 987?
The Fabspeed system for the 987 is $800. We have the 986. I think 986 Forum can fill that gap with a diy that saves at least $600!
The Fabspeed parts list+Flebay prices for the 987 kit seems to be :
1. Cone Filter 3" $20
2. Five hose clamps 3" $20
3. One 45 deg adapter hose 3" $15
4. One flex hose 3" between the adapter plate and the MAF$? 20 but tacky.
Or, Upgrade to a 3" silicone 90 deg + straight coupler +45 deg for an incremental $40?
5. One adapter plate drilled to match the old airbox mounts (free diy).
6 a 3" 'MAF' housing flange adapter either side $20. This is to connect the flex hose and the filter to either side of the adapter plate.
The flex hose or couplers really need a heat shield -they are right above the header? Maybe $20
All this is available on EBay but please avoid the Fake china stuff with 2 month lead times. Ask me how ..... and do not rely on the Feedback rating of these fakers - they manipulate it. Ask me....
Let's get hacking !
Don't forget to buy a better stainless mesh Maf screen -the 987 has this upgrade and apparently it helps protect the Maf better (slightly smaller mesh size). And a 3/4 thick x 3" air flow straightener?

[The Radium King]

i looked at doing this. even bought the lexan to fabricate the plate.

first, i researched what they were finding with the fabspeed intake on planet 9. apparently it has issues in the rain as it tends to saturate with water quite quickly.

also, there is not as much space as you might think:

- distance between inner and outer fender walls - 4". further, not a lot of room unless you pull out the rubber boot, in which case you risk sucking in a lot of dirt from the rockers.
- the 'tunnel' from the engine bay to the inner fender well - 8" long, but perhaps 3"x7" in area. i spent a bunch of time trying to find a cone or oval filter that would fit in such a small place and couldn't find anything that would work, at least without becoming a restiction in airflow - realise, the current air box IS a cold air intake, so the purpose of reinvention would be to increase filter surface area, decrease heat soak, and perhaps increase in outflow diameter so as to not restrict any downstream mods you may have made. a cone filter stuffed into the tunnel limits the amount of filter that is exposed.

futher, the tunnel is, by design, in the cabin - it is only covered by a thin layer of insulation. apparently that proved a bit of a problem in the cayman - noise if i recall. anyways, that's why i settled on the 987 airbox - a lot more filter element, less filter contact with the airbox (reduced heat soak) and better outflow. and filter changes are easy and inexpensive(ish). the frustation of the install passes after a cold beer, and the skinned knuckles heal.

[Gelbster]

Interesting that despite $800 - the Fabspeed CAI for the 987 does not work well.Thanks for the info !
I am working in this area now. The aptly termed "tunnel" is a trapezoid approx 5-1/4"" wide at the top ,8" wide at the bottom and 4-1/4" high.It does expand a bit toward the outer fender. The total depth is 9-1/2" . My current hack-plan-experiment is to use the entire tunnel as a filter housing.Then fill it with custom cut progressively finer foam filter I am playing with layers of different ppi to avoid excessive obstruction yet get adequate filtration So far I have a flat,coarse/fairly open 1" thick foam air filter immediately behind the stock louvers, then an air gap, then a finer 1" thick foam filter before it enters the engine bay.Based on the sq.in area and ppi ,it should work well but....
This is the tricky area. The rest of the system can be plumbed like the OP suggested. The air filter is difficult/uncharted waters .Ideally we need to enlarge and insulate the tunnel.It needs a small drain(with filter- done that). The enlarged tunnel would need to be a cast-in-place fiberglass 'box'.
Meanwhile, I'll see if my hack comes anywhere close to working satisfactorily before I make irreversible mods. In case people are wondering -"why is the fool doing this ? I needed to R&R #4 fuel injector. Pray to the Porsche Deity you never need to do that with the engine in place. Pelican make it sound easy but that is a subject for a different thread.

[Gelbster]

I completed my hack CAI project as mentioned above. A complete description would be too lengthy and anyway it has not proved itself in service yet.
There are a couple of aspects that seem critical.
1. Use the 'tunnel' as a casing for the new CAI filter. I managed to get around 50+sq.in of surface area for the UNI filter.It fits tightly in the tunnel. The filter foam is supported by a ramp shaped cage of 1/2" wire mesh.
A trapezoid shaped filter is attached to the back of the external louvers. I attached the custom cut foam with after-market radiator fan ties.
2. I did not use Lexan for the plate at the end of the tunnel like others did. Imho it is too heat sensitive. I used steel sheet instead. The hole was sized for a cut down4 " MAF adapter. I bolted this to the plate.SAndwiched between the aluminum Maf adapter and the steel plate is fine wire s/s mesh. I used a mesh size slightly smaller than stock.
3. Attached to the MAF adapter is a cut down, 4" to 3" 90 degree silicone adapter that .Space is tight so even a 3" MAF would need cutting down. I used the big 4" size because of flow disturbance around the 90 degree bend.
4. Connecting this 90 degree adapter to the OEM MAF tube is a challenge. The short version is that I made a 15 degree "S" bend from aluminum tube and it fits perfectly.I used a straight 3" silicone coupler to connect withe the OEM Maf+tube. I 'buried' a 3/4" air straightener in the coupler.
This complication could have been avoided by using thin-wall, spiral-wound ,wire-reinforced,flexible silicone hose. This is available on EBay from China cheaply. I hate buying technical things from such a source so struggled with aluminum instead. The big failure was trying to use the claimed 10+ degree bend capacity of hump hose. That 4 ply hose is far too stiff to bend in this situation.The thin wall silicone hose would be vulnerable to puncture/abrasion damage so I was leery of using it. Maybe with a heat shield ?
Porsche could have easily designed something like this and had a huge airbox between the inner/outer fender wall.Or just sacrifice the trunk for mechanicals!
But if you examine this aspect of the Audi R8 ,you see how they still have issues
Standard R8 Airbox breathes HOT Air!!
http://gallery.audiworld.com/albums/album234/R8070057_medium.jpg
The other item that would greatly improve this CAI is a 90 degree aluminum fitting like the T6 adapter flange.It is too small.I could not find a bigger alternative.It needs to be around 4"x6" - Cummins ?
http://new2.cxracing.com/image/cache/catalog/product/Cast-Pipe/EB-T6-300V-CAST/01-650x650.jpg

[achillies]

I put one of these in my BMW E30. The filter is sealed and open at each end so you can route the tube to an area of cooler air

KA Motors CAI - R3VLimited Forums

[Gelbster]

How would you get sufficient filtration area in a can 3"(??) in diameter? The MAF tube is that size!Remeber you are replacing the airbox which is already considered a restriction.That is why the smart guys shoe horn in the 987 airbox.

[Xpit77]

Originally Posted by bwdz

I have to say that I agree. It looks like you located it inside the engine bay right above the hot exhaust manifold. How is that supposed to draw in cold air?

It was done by the PO .

[Gelbster]

I used the "tunnel"(see dimensions below) as the air box. It is working well.There is a lot of space there for filters.It is away from the exhaust heat and frees space for working on Bank 1 Cam Cover.
That will save you needing to drop the engine !
* "tunnel" is a trapezoid approx 5-1/4"" wide at the top ,8" wide at the bottom and 4-1/4" high.It does expand a bit toward the outer fender. The total depth is 9-1/2" .

[lkchris]

Pay attention to JFP ... someone with experience.

No measured, tested proof has been posted here that the OE air box is "restrictive." No, you can't tell by looking.

A decade or more ago a fairly engineering correct test was performed with a BMW K100 motorcycle, mostly to learn about K&N replacement air filters. The testing found ZERO aitflow difference between
Stock air filter
Stock air filter half blocked off
No air filter installed
K&N

The notions that a German vehicle is poorly engineered or that its performance is "restricted" are pretty dubious. There's real world competition out there on the autobahns, and the factories know it. You're not going to create "supercharging" without a supercharger, but it would sure be cheaper and easier if you could ... and that's the fantasy appeal behind the marketing hype.

[Gelbster]

Agreed ,air flow restriction relief is not the point of deleting the OEM airbox..
The point is:
1. Intake temperature reduction especially during hot idle/slow-go ,hot weather traffic. At higher rpm/higher road speed = not a huge benefit because of air speed through the intake duct .
2. Access to Bank 1 Cam cover. This can be huge. For some tasks it is the difference between dropping the engine or not .
For example , try removing #1 injector and you'll understand the attraction of deleting the OEM airbox and using the vacant real estate in the tunnel for a replacement airfilter housing. It is a simple, inexpensive,reversible project. No oily K&N filter required :-).
An easily removable OEM Airbox would make the issue moot.

[mikefocke]

Do hot brakes affect the temp of the air ingested if you take air from the fender well as opposed to outside the body?