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-   -   home made true cold air intake (http://986forum.com/forums/boxster-general-discussions/29774-home-made-true-cold-air-intake.html)

jhandy 07-22-2011 05:15 PM

home made true cold air intake
 
5 Attachment(s)
Ok, first off I know that the car came with a cold air intake. But it was restrictive.
I then changed that out for a EVO filter system. After getting super high air intake temps/low fuel ecomomy/poor power/ high water temp... I decieded to make my own SEALED cold air intake.

KN Apollo filter 86$
Spectere coupler 8$
Lexan 5$
Epoxy 2$
Spectere 3" wall mount.
Cut off MAF mounting tube from the OEM box free$
MAF Air flow Straightener-20$
http://www.treadstoneperformance.com/product.phtmlp=2096&prodname=HoneyComb+MAF+Mass+Ai r+Meter+Airflow+Straightener

So what I did......There is a plastic tube that connects the engine bay with the fender. The plastic tube has three holes in it, this is what the OEM box bolted on to.
So remove the box, cut a sheet of lexan to cover the opening. Place a 3" port into the center of the Lexan. The KN filter came with a air trumpet that I epoxyed to the fender side of the 3" port. The epoxed the Lexan onto the engine bay side of the plastic pipeing. Put the pipe back in and bolted it to the body, sealing the intake system.
Then cut off the MAF tube from the OEM box (by the way it is 3" and my EVO MAF replacement tube was 2.7") Epoxyed the honey comb air straightener before the MAF. Then bolted up the Apollo sealed Air intake canister.

The car pulls better, I can tell it is happier not sucking in super heated air.

The only thing I would do different is drill a drain hole for water into the plastic pipe. I will do that this weekend.
Here are some pictures.

jhandy 07-22-2011 05:16 PM

3 Attachment(s)
more pictures

j.fro 07-23-2011 06:11 AM

Very nice work. I may engage in a bit of intellectual piracy :D

The Radium King 07-24-2011 09:03 AM

me too. insite did something similar in his 3.4 build, but with a bmc carbon dynamic airbox (85mm instead of 70mm, so no restriction on the 3" oem maf housing).

sparker 07-24-2011 03:20 PM

Good job - glad it worked out as per your plans!

PM me your paypal address and what I owe you for the MAF honeycomb, keen to install that in my carbon intake.

Cheers,
Sam

jaykay 03-19-2012 05:56 PM

ahhh heat shield! Was thinking the same thing and of course it has been done on here already

Kroggers 03-23-2012 12:26 AM

Nice, I have been considering the same thing.

Can I ask, how do you get the plastic tube that connects the engine bay with the fender out - can it be done with the engine still in the car?

Mrmaddbrad 03-24-2012 08:32 AM

Why do people feel the necessity to modify their cars like this? That air box was engineered for performance. I don't see how a $200 "cold air intake" will make a performance difference over the engineers that were payed hundreds of thousands of dollars to design a great intake..

WhipE350 03-24-2012 12:08 PM

Quote:

Originally Posted by Mrmaddbrad (Post 283815)
Why do people feel the necessity to modify their cars like this? That air box was engineered for performance. I don't see how a $200 "cold air intake" will make a performance difference over the engineers that were payed hundreds of thousands of dollars to design a great intake..

Not to start an argument, I tend to avoid them on the forum, however I have to respectfully disagree with part of your statement. I know many engineers that aren't worth their hundreds of thousands and many that are, either way they are often on a clock and time lines to get projects done and out the door. Rockets blow up and planes crash. How is it that these same engineers don't get it right the first time and seem to find more hp each year from the same engine. Even the new Boxster has reduced engine size and boosted hp. I'm not implying his mods are any better but to answer your first question I assume because he is creative and it is fun. If I wanted a Boxster to not tinker with I would have bought a 2011 and not a 2000. Worst that can happen is it throws a cell and he puts the old system back in.

JFP in PA 03-24-2012 12:43 PM

Actually, the worst thing that can, and usually does happen, is that the "trick" aftermarket system makes less power on the dyno. I do not know how many aftermarket "improved cold air" systems (which is a misnomer as the factory system is a cold air set up to begin with) people have looked at and properly tested before and after on a dyno, only to find they added nothing, or even took power away............. I think a truely more interesting experiment would be to determine how much time and money have been wasted on this.

Topless 03-24-2012 01:08 PM

Quote:

Originally Posted by JFP in PA (Post 283835)
Actually, the worst thing that can, and usually does happen, is that the "trick" aftermarket system makes less power on the dyno. I do not know how many aftermarket "improved cold air" systems (which is a misnomer as the factory system is a cold air set up to begin with) people have looked at and properly tested before and after on a dyno, only to find they added nothing, or even took power away............. I think a truely more interesting experiment would be to determine how much time and money have been wasted on this.

Or better yet, the "tuner" drops a screw inside the new intake.... where did that little thing go... no matter. He fires up the motor with his new high tech intake mod, the motor ingests the screw, it gets jammed in cyl #2 intake valve, piston goes TDC, valves bend and pistons break. True story if you substitute "Honda" for "Porsche".

YMMV

jacabean 03-24-2012 02:46 PM

i think a larger throttle body and tee would be a better project to do.

JFP in PA 03-24-2012 02:56 PM

You need to be careful there as well, as you increase the TB size, you significantly impact not only fuel/air mass, you also change its velocity is such a manner that engine response off part throttle acceleration can become sloppy because of the sudden mixture velocity drop in the intake runners.

These systems need to be carefully matched on the flow bench to maximize response and power out put; otherwise the end result can be questionable to drive. Anyone that has ever installed too big a carburetor on an engine knows exactly what I am talking about, high RPM power gains, lousy drivability............ Bigger ain’t always better.

Topless 03-24-2012 04:44 PM

Quote:

Originally Posted by jacabean (Post 283848)
i think a larger throttle body and tee would be a better project to do.

As long as you are attaching that larger TB to a shiny 3.6L motor you got a winner. :)

jaykay 03-24-2012 10:32 PM

Actually I think jhandy and sparker's intake arrangements are quite good and show some nice design sense.


Gentlemen some points to consider:

-Some are into design development and testing (hard to do accurately without lots of cash) and some are not. Perhaps a hobby to some? To each his own.

-To some an extra 10hp is worth looking for (track; racing...); optimization etc. Don't worry about it if you are just cruising about

-There seems to be some evidence to suggest that the 3.2L has been detuned. This would likely include intake flow area/lose restrictions. Of course you have to correct them all (and no warm air) in unisom in order to have some hope of good results.

-Of course big air box intake systems are likely the most efficient and the way to go

..... but I wouldn't be too quick to discard jhandy and sparker's intake arrangements and lump them in with crappy hot "cold" air intakes. They are actually very good conceptually; have a closer look and understand. They are sealed cold air intakes that could outflow the stock air box. One would have to test to know. Their arrangements are not unlike (perhaps better as they offer better filter protection) the set up now used on some racing Caymans.

-Have a look inside the stock airbox you will find a small snorkle in there. What is its flow area?

-Is the stock TB @ 68mm dia (less than three inches) an intake choke point?

-Is the the intake runner velocity ultimately metered at a 3.5" dia. for the left and right plenums and is this flow dia arrangement better served by a larger TB?

-What are the experiences of IPD plenum users with larger TBs?

Ghostrider 310 03-25-2012 02:27 AM

I agree with Jaykay, there are also the factors in manufacturing such as cost containment and especially German TUV noise standards. I think TUV is the reason the intake sounds are so muffled. Some 986 information seems contradictory, for example, there are numerous people saying reducing the back pressure with headers would reduce the HP as well. Theory was based on a given needed amount of BP for the flat six to run correctly. In my experience the headers made a difference, I didn't measure it but I did hear and feel it. I've also noticed when reading about modded Porsche cars in excellence, exhaust is frequently changed in diameter or configuration for more power.

Gelbster 12-19-2016 06:33 PM

The best aspect of this diy mod is deleting the huge, obstructing stock airbox. With the old airbox removed (but useful parts salvaged & reused) ,access to 4,5,6 from above is hugely improved.
One small detail The MAF tube is 3" at the intake end and 3-1/4" where it connects to the corrugated hose. So think carefully about that oddball 3-1/4" size(82mm+/-) before you just buy a 3" Spectre 9405 MAF tube.
I did buy the 9405 but made a rubber sleeve/adapter for one end.
The other idea is to use the cavity between the inner and outer fender as a cool-air plenum and air filter box. There are lots of creative ways of using UNI air filter foam in that space. And it should be a cooler location than the stock airbox which sits right above the Bank 2 header.
I found it very useful to remove the hinged ,metal body panel .Not just the engine cover,not just service mode, remove the entire rear cover that abuts the truck lid. It is the huge arc shaped 'lid' that fits forward of the trunk lid.It is just some pins and E clips.That makes it sooomuch easier.
This link may help:
http://986forum.com/forums/diy-project-guides/9418-intake-install-step-step-pics-video.html
The obvious problem in the diy is the hot,dirty location of the new air filter and the lack of detail on how to extract the airbox(disection is fastest!).The location issue for the air filter is addressed by the suggestions at the beginning of this post.

Xpit77 12-20-2016 04:05 AM

When I bought mine it had a diy CAI. Basically the PO removed the box cut the tube and stuck a KN cone filter on it. I replaced the cone with a barrel type KN and installed an Injen sheild. It`s not pretty but it sounds good and doesn`t throw codes.http://986forum.com/forums/uploads02...1482239108.jpg

particlewave 12-20-2016 04:51 AM

That's a hot air intake. :(

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

bwdz 12-20-2016 05:58 AM

Quote:

Originally Posted by particlewave (Post 520134)
That's a hot air intake. :(

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

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?

Boxtaboy 12-20-2016 06:51 AM

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 12-20-2016 07:55 AM

Boxster CAI ,airbox,MAF tube,Spectre,UNI, plenum
 
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 12-20-2016 08:00 AM

Quote:

Originally Posted by particlewave (Post 520134)
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 12-20-2016 09:09 AM

I was mostly referring to Xpit's K&N setup. Nothing but hot air there. :eek:
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 12-20-2016 09:34 AM

Quote:

Originally Posted by Gelbster (Post 520152)
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 12-20-2016 12:33 PM

Quote:

Originally Posted by The Radium King (Post 520165)
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 12-20-2016 01:10 PM

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 12-20-2016 01:41 PM

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 01-12-2017 06:58 PM

CAI that is actually cold,inexpensive,makes a cool sound and may work
 
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 01-12-2017 07:37 PM

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 01-13-2017 07:44 AM

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 07-08-2017 07:32 AM

Quote:

Originally Posted by bwdz (Post 520141)
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 07-08-2017 08:02 AM

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 07-08-2017 08:52 AM

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 07-08-2017 09:05 AM

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 07-08-2017 01:40 PM

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


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