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YOUR RESEARCHHemholz chamber "cold air intake" airbox mod...
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Tighten aluminum plate
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Performed · outcome unconfirmed · Original poster
Its a wing nut tightened aluminum plate with an expandable rubber seal under it that bellows out as you ratchet it down.
Leading evidence: 'Tighten aluminum plate' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check though' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Suggestion
Don't think this will pass the CA smog visual check though.
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Suggestion
Oatey 33401 is available on Amazon, as are other options if you search for 2" test plug.
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Suggestion
I've actually been using the 3" and 4" versions for actual plumbing work and never had one back out.
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All just wanted to post how I did mine.
A popular company sells this mod for 200. Its called the cold air intake, i think they claim 10hp
Its REALLY easy to do for 25 bucks
Buy the smooth silicone intake pipe from ebay for the 996. It cost around 20 dollars or so. Maybe 25. Do a search and you will find them. They have them in red and blue. My car is guards red, so I chose red.
Take out the hemholz box per the million online instructions...really easy. You should now have a open hole in the airbox. Go buy the red thing in the picture from lowes for 5 dollars. Its a wing nut tightened aluminum plate with an expandable rubber seal under it that bellows out as you ratchet it down.
Its totally air tight and firm. Works perfect. If you want, add a lock nut over the wing nut so it doesn't back out. I didn't do that...its tight as heck so it works just fine...but I will probably do it at some point just to be safe....
Results
- Noise improvement
- Throttle is more responsive
- Could be the noise faking me, but I feel like the car has a tad more pull now
- Stock air filter
No codes, no issues yet. 100s of miles....
The Lowe's gripper plug seems to be the best budget hardware solution yet.
Gawd, I can't believe I just said that and participated in another airbox mod thread...
O-Tay! Nice flashback!
The warning statement definitely makes this cooler than the "orange cap" version of the same mod.
Oatey 33401 is available on Amazon, as are other options if you search for 2" test plug.
Great little mod....anybody know where I might get the plug in Europe? On the bay the plug cost $6 but delivery to France is $35!!!!! Any help appreciated
Incidentally, fabspeed does not market this as a cold air intake. They call it a "cold air upgrade," and the claimed HP is 4-5, not 10.
If you're wondering (like me) just how this could be called a cold-air anything, since it still connects to the factory airbox...the smooth pipe has less surface area than the corrugated OEM pipe. Less surface area = less opportunity to transfer heat from the intake pipe to the air charge.
I think the idea is that the smooth pipe causes less turbulence, hence less back-pressure, hence Fabspeed's claimed increase of 128 HP. So, they are no longer calling it a cold air intake? They used to.
Hey, anyone got a hemholz box they want to sell for cheap? I may be concerting mine back.
Since you have to disassemble the airbox to remove the resonator, why not just run a bead of black RTV around the rim of the plug, inside the airbox? Add a little loc-tite on the wing nut, and you won't ever have anything falling apart...
Please tell me 128 is your typo.
What one seller reported on their website is that the stock tube constricts when hot and the replacement doesn't ensuring constant air flow.
Ha! 'Twas my sarcasm. Fabspeed claims (or used to claim, anyway) a 14 HP increase using this red hose. Ummm... yeah.
Schnelly, I'll PM ya regarding the box.
Wow, once again we got a lot of worrysome bunch. How about the worried folks just leave their airbox stock and gain some sleep at night.
I've actually been using the 3" and 4" versions for actual plumbing work and never had one back out. But you can also just use some blue loctite if it makes you feel better as an alternative to a nylock nut.
it won't back out, its tight as hell, and super easy to check everytime you pop your engine hood....As you say a little loctite or locking nut and move on. For me I may never bother with either...
The plug I purchased was $5.39 @ Lowes Hardware, The Silicone elbow was $20.00 on Ebay and the little filter I had it from a prior project.... lol Im happy with the results.
No, I ran it open for awhile infact. That's why I never understand why people hoseclamp it to death since it's already sealed. But take note, if you remove the resonator, you will need to seal the hole.
Can this mod be easily reversed if not needed? PLUS would someone be kind enough to post a video of the new sound of the car with this mod in place. Thanks
Nice! For those of us who don't want to divert long from other P-projects, can you tell me the length and diameter of the silicone hose to get?
Or better yet, give an EBay link to an example?
Thanko mucho.
It's been a while since I did this, but I think that the resonator is inside the airbox and you can't access the resonator without removing the airbox from the car because of how the airbox is assembled.
1) Grab a 32oz bottle of Gatorade.
2) Drink Gatorade
3) Loosen small hose clamp on airbox
4) Pull up small hose lightly
5) Drop Gatorade lid upside down underneath airbox hose.
6) Place hose back in place
7) Tighten hose clamp
Still stock looking and Heinholtz is disabled.
This works for 996 & 997 airboxes
This is a source reference. Confirm exact model applicability in the original material.
