Did an internet search and found the attached dyno graph. Shows a Cayenne Turbo with a Cargraphic exhaust before and after the plenum install. Not saying it's definitive, but it might be where IPD came up with their +30 HP claim. It's old; from 2006.

 

IPD responded and mentioned that its more for durability as someone here mentioned (crack connectors) and not HP

 

Wow. That's pretty damning. If I had bought one wanting HP I'd be demanding at least some of my money back for false advertising.

 

After installing mine months ago , all I can say its that I lost a little torque in the lower rpm and gained a little in the uper rpm

 

That dyno can't be right. There is more to that dyno than just an IPD plenum. Maybe the user had their plastic one crack or the first run was heat soaked? It's saying you gain 30 WHP (not crank) from just the IPD plenum. That's at least 40 crank HP with a modest 28% power train loss, and that's at 96 degrees F. So, that'll be at least 50 crank HP at cooler 60-70 degrees. If I could make 50 crank HP and get damn near close to Turbo S power (that has more boost and bigger IC's) - hell yeah I'd be all over that.

And, for me at least, the fact there are no dynos listed on his site, most people can't figure out if they're butt dyno is right, and apparently, the owner of IPD even claims it's just for reliability. You read their website and they have a section of buyers using the IPD plenum and doing a dyno, and he makes it seem like he's surprised by the results.

I think we can officially call this snake oil.

 

WOW!!!!!!! for years we have been hearing it is for failure of these pieces but like I and others have said with years of Porsche ownership under our belts... especially with the models these are most directly sold to.... I have never seen a failure. That being said IPD has always used the HP gain to market this product and to justify the price. If we truly get 20-30HP without any additional mods then this is the cheapest HP upgrade available for our cars.

After IPD's response.. I will never buy this product unless...
1. mine fails and fails consistently and purchasing this product will lower my overall TCO if I don't have to keep replacing stock unit.
2. they are able to prove HP gains (of 20-30 like they have stated on their site)

on to the next mod!

 

Yep, this proves the snake oil theory for sure.

 

IPD 'finna get in some trouble.

 

None of the photos shows the main difference which is the divider in the middle and how it directs airflow. The stock plastic piece allows the air from the two inlets to directly collide with each other before going into the throttle body. The IPD piece allows each path to turn and then merge in a much more parallel flow as it enters the throttle body. You can see straight through the inlets on the stocker, not with the IPD.
The only real gain I've seen with mine over the years is about 0.2 MPG and that's about it. Eventually I plan on running water or meth injection and this will be easier to mount a nozzle to over the stock piece for sure.
IMO, save your money unless you find a used one like I did. And even then make sure you get a smoking deal.

 

So after reading this, and having ordered my plenum, I am contemplating returning it. It hasn't been installed yet.

I guess I could always be the guinea pig for the group as this forum has given me so much good advice (long time reader/lurker, finally registered) and dyno a 'before' and 'after' forever dispelling or proving the myth?

 

Save your time and money and carry out an extra oil change instead.

 

Haters will hate. IPD owners know its true value.

 

True value of clever marketing.

 

Just a little bump and thank you to everyone who contributed to this thread. I'm looking at what if any mods I'd consider to my current TTS, 4th Cayenne. I was thinking plenum and diverter valves first. I feel $1k richer now that I'm going to do nothing for the time being. Thanks.