Can I completely remove the Hemholtz resonator on stock airbox/intake

[ninsei]

Hi. I have the stock airbox and stock intake hose on my 2000 C2 Tiptronic. I'm changing the air filter tomorrow and was wondering if I could mod it. I see some folks remove the Hemholtz box and block off that 1.5 inch hole. But I have the stock hose so I guess I would need some kind of nipple for it to attach to? Anybody do this?

[fpb111]

Many before you grasshopper:

http://forums.rennlist.com/rennforums/996-forum/397860-anyone-want-a-orange-cap.html

[ninsei]

Thanks. So I completely removed the Hemholtz box and replaced it with some PVC, orings and threaded cap to make a good seal on both sides. But it's not blocked off: the PVC I used is hollow so it lets un-Hemholtzed air through that little tube in the stock intake hose. Now I have rough idle (almost stalling at idle). But driving is great.

[ninsei]

So, I guess what I'm asking is: should I block off the small Hemholtz hose, or is it ok to leave it open (not open to unfiltered air, of course), without the Hemholtz box there?

[fpb111]

Pic? Sounds like you have created an air "leak" past the MAF sensor.

[ninsei]

Thanks for the reply. No, no air leak past the MAF. I just removed the entire Hemholtz box and nipple piece (it's all one piece), and replaced it with a hollow nipple, thru the airbox, that the small Hemoltz tube on the stock intake, connects to. So now, the small tube can actually suck (filtered) air into the intake, whereas, before, it was restricted by the Hemholtz box.

[wyovino]

Many people have done that mod and I believe you need to cap off the hose. That being said, i think i read that the maf actually depends on the turbulance created by the box, so i've opted not to do the mod.

Edit: I could have sworn I read an excerpt from some Porsche documentation that said the accuracy of the MAF relied on the turbulance created by the stock airbox. I've search everywhere and can't find any reference to that, so you can take my comment above with a grain of salt.

Edited August 28, 2012 by wyovino

[williampeyton]

Oh okay I guess the first thread on this was deleted and RE THREADED. I am very new, what is ORANGE CAP and how does it work, can someone send a pic or diagram on how to use. When It comes to the 996 stock airbox what is this Hemholtz box is that the air intake box. If yes how did you bypass it to get a better sound. I also have a 2000 C2 Tiptronic S, with after market headers and mufflers. The exhaust note sounds good and want to make it sound better. Please I need help, ohh that link only works if you have a log on with rennlist site. Can someone please post more helpful links and / or pics to show what to do and how to do, thank you

[ninsei]

Hi. So I capped off my PVC mod that replaces the whole Hemholtz box and now idle is smooth and the MAF errors are gone. Who would have thunk it: the MAF/DME coding is super sensitive to any change in airflow.

[fpb111]

Oh okay I guess the first thread on this was deleted and RE THREADED. I am very new, what is ORANGE CAP and how does it work, can someone send a pic or diagram on how to use. When It comes to the 996 stock airbox what is this Hemholtz box is that the air intake box. If yes how did you bypass it to get a better sound. I also have a 2000 C2 Tiptronic S, with after market headers and mufflers. The exhaust note sounds good and want to make it sound better. Please I need help, ohh that link only works if you have a log on with rennlist site. Can someone please post more helpful links and / or pics to show what to do and how to do, thank you

Go to the link in #2 above. and look at it. In that link (the one referenced in post #2 above) Post #1 has pic of the cap, post #11 has pic of where to put it.

[williampeyton]

Oh okay I guess the first thread on this was deleted and RE THREADED. I am very new, what is ORANGE CAP and how does it work, can someone send a pic or diagram on how to use. When It comes to the 996 stock airbox what is this Hemholtz box is that the air intake box. If yes how did you bypass it to get a better sound. I also have a 2000 C2 Tiptronic S, with after market headers and mufflers. The exhaust note sounds good and want to make it sound better. Please I need help, ohh that link only works if you have a log on with rennlist site. Can someone please post more helpful links and / or pics to show what to do and how to do, thank you

Go to the link in #2 above. and look at it. In that link (the one referenced in post #2 above) Post #1 has pic of the cap, post #11 has pic of where to put it.

Thank you, I was being lazy and did not want to register to RENNLIST kind of feel like a Porsche website hooker. Dont want to spread myself around, I did go there and register so that I can see what you and everyone else was talking about. I went online and orderd it so cant wait to get it and see if it works. So let me get this straight, this will work as good as the K&N Air intake system right, as far as sound goes.

[williampeyton]

Okay I recieved my RED CAP today and followed the instructions off of RENNLIST. I capped the secondary opening in the Holtzsresonator Box and made sure all the fitting were tight. I gunned the engine and heard no noticeable difference. I found an open deserted street and floored the gas pedal for about 100-200 meters and still heard no noticeable difference in sound from either exhaust or air intake. Like I mentioned before I have an after market headers and exhausts. My car does not sound like a stock 996. Did I do something wrong or this will only work for 996s that are all stock and not for 996s like mine which already have some modifications. If I have done everything correct, K&N Air Intake modification sounds really good now.

P.S. I have a second red cap, if someone wants it let me know it yours.

[williampeyton]

UPDATE: Today I rechecked everything made sure all hose clamps were secure and tight and made sure that my RED CAP was pluged in the hole snuggly. Everything was in place except my main hose to the throttle body was a little crooked. Before repositioning and clamping down the hose. I checked the throttle body and cleaned around the edges of the flap. There was a little but of extra grease around parts that move. I repositioned the hose correctly this time and reclamped everything. I took it out on the highway (I-5) when there was no cars around and switched it to manual. OH BOY it started singing especially between the 5 and 6 rpms. I have to admit I had a little chubby going. As far as performance the torque seems the same, however it got up to 90Mph alot quicker then I remembered. If this is the same performance and sound I will get using the other after market air intakes. Then yes this is way cheaper (FREE) and safer for my car, because im still using the OEM parts that will not damage my car. I Love my car even more and love this site for Porsche lovers like me, RENNTECH IS THE TRUTH.

[fpb111]

Another happy customer!!

[wyovino]

So, I guess what I'm asking is: should I block off the small Hemholtz hose, or is it ok to leave it open (not open to unfiltered air, of course), without the Hemholtz box there?

ninsei - you never reported back about the sound.

Does anyone know if there a big difference in sound between the full monty (what ninsei did) and just doing the orange cap mod?

[fpb111]

Pretty much the same. Blocking the small tube is what enhances the intake noise.

Edited August 29, 2012 by fpb111

[ninsei]

Ninsei here. I notice no difference in the sound. but all my MAF issues are gone, now that I plugged the Hemholtz hole.

[wyovino]

Can someone explain the science behind this?

[RFM]

I certainly do not.

[williampeyton]

Ninsei here. I notice no difference in the sound. but all my MAF issues are gone, now that I plugged the Hemholtz hole.

Okay from what I read and understand is this. The part you cap off has to do with sound resonation, meaning as the engine is sucking in more air and the engine noise becomes louder. This box helps by keeping the noise down and air intake noise down as well. In sport models this same box has a valve attached to it and when you put it in sport mode the valve closes off that port and makes the engine sound louder. You ask why would someone not have it on sport mode all the time. If you are being considerate to your neighbors and letting the car warm up, haveing the sport mode makes it louder some what. When the sport mode is off then it sound like regular exhause note for a stock vehicle. Basicly all your doing is making the engine and air intake noise louder or having it permanetly in sport mode. The peek of the noise is when you have the engine open at full throttle while your driving. In the driver seat you cant hear it as loud or clear, but the cars next to you or around you can. When I downshifted to 3rd gear and stepped on the gas. The people around me turned their head in my immediate area. So my engine noise and not speed is what got their attention. As far as performance gain none, however as far engine noise louder, a definite yes. Im thinking about using the RED TUBING for air intake, instead of stock tubing for air intake. it suppose to give a little performance gain because the tubing is smooth and gives very little restriction to air flow induction. To where as the stock hose intake is not smooth and has some type of air resistance or air dams to it. Like i said i have been researching the best air intake for months now and from what I concluded is any air filter that has oil on it, you have a 50/50 chance of messing up your MAF sensor. As you know these cars are tough but sensitive, one sensor can throw off another sensor and next thing you know you have ghost problems in your car all because one sensor is off. So to alleviate that I am going to keep the stock air box and filter and maybe change out the stock air intake tube to RED TUBE.