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tbrown
Paul Ricard


Joined: 05 May 2007
Posts: 3429
Location: Fra Mauro Highlands

2007 Porsche Cayman 987

PostPosted: Sat Jan 29, 2011 1:21 am    Post subject: Reply with quote

rajkumar911 wrote:
Just looking at the HHR and the positioning in the box and where the air passes into the tube housing the MAF - I really don't see that there would be an increased airflow into this tube by removing the HHR
The airbox will have a larger volume of air in it
if anything, the HHR removal means that air now occupying this space is likely to cause disturbance to the air that direct goes upwards and into the tube.
No it won't

re the orange cap mod. That mod blocked the HHR (keeping the spur) and resulted in a change of sound. Therefore it is possible that air passing through the spur and HHR does cause some harmonics that influence sound.
The resonator [clue is in the name] was put in to reduce the exhaust noise to comply with the US restrictitions AFAIK, so removing it from the system will obviously impact on sound.


I'm with GT4 all the way on this one
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Cayman S
Ex 996C4 Polar Silver 125k
Ex 996C2 Ocean Blue 143k
 
  
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GT4
Nordschleife
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Joined: 08 Nov 2008
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Location: Hertfordshire and Hampshire


PostPosted: Sat Jan 29, 2011 1:43 am    Post subject: Reply with quote

Just to clarify, this is without typos:

Quote:
Now I am not debating the attractiveness of the noise (which is personal) and I even added a question mark to the statement "improvement?" on page one as I realise everything from PSE to sports suspension to colour isN'T objective. But the HHR will change the noise charActeristics and the noise level (loudness).
 
  
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rajkumar911
Monza


Joined: 23 Nov 2009
Posts: 162



PostPosted: Sat Jan 29, 2011 9:44 am    Post subject: Reply with quote

tbrown wrote:
rajkumar911 wrote:
Just looking at the HHR and the positioning in the box and where the air passes into the tube housing the MAF - I really don't see that there would be an increased airflow into this tube by removing the HHR
The airbox will have a larger volume of air in it
if anything, the HHR removal means that air now occupying this space is likely to cause disturbance to the air that direct goes upwards and into the tube.
No it won't

re the orange cap mod. That mod blocked the HHR (keeping the spur) and resulted in a change of sound. Therefore it is possible that air passing through the spur and HHR does cause some harmonics that influence sound.
The resonator [clue is in the name] was put in to reduce the exhaust noise to comply with the US restrictitions AFAIK, so removing it from the system will obviously impact on sound.


I'm with GT4 all the way on this one


Agreed more air in box if HHR removed, but does that equate to more air (flux) going through the tube? And does that equate to extra BHP?

Any data out there?

Btw, my point about the orange cap mod was that maintaining but blocking the HHR from the spur also changes noise...according to rennlist discussions
 
  
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GT4
Nordschleife
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Joined: 08 Nov 2008
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PostPosted: Sat Jan 29, 2011 10:33 am    Post subject: Reply with quote

rajkumar911 wrote:
Agreed more air in box if HHR removed, but does that equate to more air (flux) going through the tube? And does that equate to extra BHP?

Any data out there?

Btw, my point about the orange cap mod was that maintaining but blocking the HHR from the spur also changes noise...according to rennlist discussions


Are we going round in circles here, or is there some reason page one doesn't show up on your browser?

There was no expectation of any BHP gain, and any would be incidental as this is primarily a noise (loudness) mod.

However, if as suggested:

1) tube smoothed
2) performance filter fitted
3) filter surface area increased (or derestricted)

Then logic dictates more and quicker air flow should result. (and thus if the ECU is happy to oblige, more fuel and more power, but that is another discussion entirely)

As this is one of the cheapest mods and, as already stated, meant for loudness outcome I don't believe anyone has spent hundreds or thousands of pounds on RR stats, but you are welcome to try.

In any case, as the performance filter is likely to be the most significant contributer, using the manufacturer's own (dubiously optimistic) figures would be a good proxy, but as said, largely irrelevant if this is done for the noise.

As regards the Orange Cap mod, this mod is derived from that and if you search for "Orange Cap" and specifically my posts, you will see how they compare, but my original post was to describe but one ultimate incarnation of this kind of HHR mod (on my car), rather than an entire treatise on induction mods and their physics (you'll note not one mention on EVOMS, K&N 5700 etc etc).

However, the general principle behind all those mods (including Orange Cap) is covered by the description of how the HHR is an anti-noise resonance device, therefore by extension, its removal or modification will obviously effect or negate its noise-cancelling abilities.

One thing I would caution on in the Orange Cap mod is the possibility of the cap coming loose and making its way up the y-spur and into the intake system/throttle body.

Do a search for my posts on Orange Cap mod for more details, but basically I didn't want to include it here for the reason it is not engineeringly ideal nor optimised since it still includes unknown (but turbulent) Venturi effects (it is an untuned HHR, so goodness knows what effect it has on the induction pulses).
 
  
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rajkumar911
Monza


Joined: 23 Nov 2009
Posts: 162



PostPosted: Sun Jan 30, 2011 8:11 pm    Post subject: Reply with quote

Thanks, GT4. Sorry for degenerating your first page thread into an episode of nerd-fest. Your input is always valuable worship

At least we agree that we're changing the noise characteristics and the jury is out on performance gains thumbsup

If I can skimp on next years servicing costs then I may invest in some RR stats to clarify what's going on Cop
 
  
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allan108
Trainee


Joined: 30 Apr 2010
Posts: 90
Location: Cambridge / Edinburgh

2002 Porsche 996 Carrera 2

PostPosted: Tue Mar 01, 2011 6:50 pm    Post subject: Reply with quote

I was looking forward to doing t his mod, however i see tiptronic cars are not eligible? is there away around this, as i would like to do it?
 
  
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allan108
Trainee


Joined: 30 Apr 2010
Posts: 90
Location: Cambridge / Edinburgh

2002 Porsche 996 Carrera 2

PostPosted: Tue Mar 01, 2011 6:51 pm    Post subject: Reply with quote

I was looking forward to doing t his mod, however i see tiptronic cars are not eligible? is there away around this, as i would like to do it?
 
  
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JKH112
Spa-Francorchamps


Joined: 28 Jan 2011
Posts: 358
Location: Bristol

2001 Porsche 996 Carrera 2

PostPosted: Tue Mar 01, 2011 8:17 pm    Post subject: Reply with quote

allan108 wrote:
I was looking forward to doing t his mod, however i see tiptronic cars are not eligible? is there away around this, as i would like to do it?

From page 1 I presume the reason tips cannot have this mod is that they have an extra take off from the intake tube, which the aftermarket replacements don't come with. If this is the case then can the HHR be removed from tips but the standard intake hose retained, maybe with a better filter element? The spur that normally goes to the HHR would be redundant, but if it was reattached to the airbox lid and not blanked off then it would just allow more air from the post filter side of the airbox through to the intake pipe, or am I missing something? (i realise that the benefits of a smooth tube will not be gained).
 
  
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allan108
Trainee


Joined: 30 Apr 2010
Posts: 90
Location: Cambridge / Edinburgh

2002 Porsche 996 Carrera 2

PostPosted: Tue Mar 01, 2011 8:33 pm    Post subject: Reply with quote

JKH112 wrote:
allan108 wrote:
I was looking forward to doing t his mod, however i see tiptronic cars are not eligible? is there away around this, as i would like to do it?

From page 1 I presume the reason tips cannot have this mod is that they have an extra take off from the intake tube, which the aftermarket replacements don't come with. If this is the case then can the HHR be removed from tips but the standard intake hose retained, maybe with a better filter element? The spur that normally goes to the HHR would be redundant, but if it was reattached to the airbox lid and not blanked off then it would just allow more air from the post filter side of the airbox through to the intake pipe, or am I missing something? (i realise that the benefits of a smooth tube will not be gained).


this is what i meant....... Embarassed

that makes sense to me, as the only change is the hhr box, so if we just leave the silicone hose out. im just after the better sound, not interested in the marginal performance gain!!!!
 
  
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tbrown
Paul Ricard


Joined: 05 May 2007
Posts: 3429
Location: Fra Mauro Highlands

2007 Porsche Cayman 987

PostPosted: Tue Mar 01, 2011 10:50 pm    Post subject: Reply with quote

allan108 wrote:
I was looking forward to doing t his mod, however i see tiptronic cars are not eligible? is there away around this, as i would like to do it?


That small pipe is only on US cars and the makers of the CAI tell you the silicon hose can't be
fiitted to a tip.
Open your engine bay and if you haven't got the little pipe, away you go.
Mine is a tip by the way and I have done the mod. Thumb
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Ex 996C2 Ocean Blue 143k
 
  
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GT4
Nordschleife
Nordschleife


Joined: 08 Nov 2008
Posts: 30174
Location: Hertfordshire and Hampshire


PostPosted: Wed Mar 02, 2011 12:08 am    Post subject: Reply with quote

ABSOLUTELY DO NOT RE-ATTACH THE Y-SPUR.

If you bypass the MAF (ie allow air into the throttle body via the Y-Spur) the engine will run too lean and overheat.

This unmetered air and resultant lean running may even result in piston seizures in extrema.

-------------------------

If you want to mod a Tip, and it has the transmission breather pipe (AFAIK later SAI models) use a mini-cone filter.

Quote:
For Tiptronic and Anniversary edition cars, there is a small extra hose running into the factory Intake hose which must be taken out and have a small intake breather placed on the end. This hose is required and cannot be plugged up, so you must get a small intake breather from a local speed shop or AutoZone which can be zip tied to the end of the hose so the car runs properly. K&N and a few other entities carry one and there is photo to the side of what it looks like.






Affix to breather pipe end and cable tie somewhere out of harm's way.
 
  
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JKH112
Spa-Francorchamps


Joined: 28 Jan 2011
Posts: 358
Location: Bristol

2001 Porsche 996 Carrera 2

PostPosted: Wed Mar 02, 2011 7:58 am    Post subject: Reply with quote

Thanks, I see that the HHR pipe joins after the mag, so it will have to be blanked off if the standard hose is retained.
 
  
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GT4
Nordschleife
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PostPosted: Wed Mar 02, 2011 8:30 am    Post subject: Reply with quote

That would work (in the sense of retaining MAF control).

You would have to reliably and securely block off using, say, a tapered bung that you could force in there and jubilee clip. It must be air tight.

However, the couple of inches of Y-spur remaining would still add some unknown (and unwanted) Venturi effects.
 
  
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allan108
Trainee


Joined: 30 Apr 2010
Posts: 90
Location: Cambridge / Edinburgh

2002 Porsche 996 Carrera 2

PostPosted: Wed Mar 02, 2011 10:05 am    Post subject: Reply with quote

so basically, if there is no transmission breather line, then this modification will be fine, including the silicon hoses supplied, and not effect the MAF.
sorry to rattle on, i am not that technical, so i sometimes struggle to follow the more technical threads... Embarassed
 
  
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GT4
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PostPosted: Wed Mar 02, 2011 1:18 pm    Post subject: Reply with quote

I not sure what mod you are referring to?
 
  
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allan108
Trainee


Joined: 30 Apr 2010
Posts: 90
Location: Cambridge / Edinburgh

2002 Porsche 996 Carrera 2

PostPosted: Wed Mar 02, 2011 4:13 pm    Post subject: Reply with quote

sorry, by transmission breather, i meant intake line, i have been researching transmissions for my x5 and its getting to my head.

sorry i think i am confusing everything now! basically wanted to know if i can add the intake mod thats on this thread to my tiptronic car in some way, and it appears i can as long as there is no y piece on the hose.
 
  
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GT4
Nordschleife
Nordschleife


Joined: 08 Nov 2008
Posts: 30174
Location: Hertfordshire and Hampshire


PostPosted: Wed Mar 02, 2011 4:31 pm    Post subject: Reply with quote

Surprised

Erm, you can do the original mod, as page one and IF you have a breather pipe, cap it with a mini filter (you may even be able to use an aquarium fitting).

The HHR is attached to Y-spur, breather (IF fitted) is attached to main trunk of Y-pipe (intake tube):



I do not consider this ideal, but if you decide to remove the HHR and retain Y-pipe you must securely stopper both the airbox aperture left by the HHR and the free end of the Y-spur.
 
  
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allan108
Trainee


Joined: 30 Apr 2010
Posts: 90
Location: Cambridge / Edinburgh

2002 Porsche 996 Carrera 2

PostPosted: Wed Mar 02, 2011 6:35 pm    Post subject: Reply with quote

ok, i get it now. thanks! sorry i have caused a lot of confusion.
 
  
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JKH112
Spa-Francorchamps


Joined: 28 Jan 2011
Posts: 358
Location: Bristol

2001 Porsche 996 Carrera 2

PostPosted: Wed Mar 02, 2011 7:04 pm    Post subject: Reply with quote

tbrown wrote:
allan108 wrote:
I was looking forward to doing t his mod, however i see tiptronic cars are not eligible? is there away around this, as i would like to do it?


That small pipe is only on US cars and the makers of the CAI tell you the silicon hose can't be
fiitted to a tip.
Open your engine bay and if you haven't got the little pipe, away you go.
Mine is a tip by the way and I have done the mod. Thumb


My 996.2 tip (uk car) has the small pipe. Is your car a 996.1? If it is then that would explain the difference.
 
  
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GT4
Nordschleife
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Posts: 30174
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PostPosted: Thu Mar 03, 2011 1:12 am    Post subject: Reply with quote

As mentioned earlier, the later SAI (Secondary Air Injection) equipped Tip cars have breather pipes.
 
  
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