Stock boost

[kas996]

I just picked up an '05 CTT and love it. I'm trying to get up to speed on these things. I've only had it for two weeks, but so far I've changed the engine oil & filter, spark plugs & coils (all of my coils had cracks btw), air filters and particulate filters. I was surprised to see that my coils were all cracked as it ran very smooth ( and still does). My question is: The boost gauge indicates up to .8 bar, but I'm only seeing .5 bar at WOT. Seems like I might have some investigating to do to find a leak in the system, but I'd like some confirmation before I start trying to find the needle in the haystack.

Thanks

Keth

[mmmbeer]

Stock boost pressure for the 450HP Cayenne Turbo should be max 0,6 bar which reduces slightly to about 0,5 bar at higher rpm.

The 500 HP E81 Powerkit should have max 0,8 bar reducing to 0,65-0,7 at higher rpm. (Not verified, but a reasonable assumption based on different sources, feel free to correct this one).

The 521HP Turbo S should have max 0,9 bar reducing to 0,75-0,8 at higher rpm. (Not verified, but a reasonable assumption based on different sources, feel free to correct this one).

These are the standards; there are several other factors that may contribute to the actual boost pressure, such as atmospheric conditions, fuel quality and such detected by the engine management system.

The in-dash boostgauge is not known to be very precise so it might be a bit off.

[kas996]

Stock boost pressure for the 450HP Cayenne Turbo should be max 0,6 bar which reduces slightly to about 0,5 bar at higher rpm.

The 500 HP E81 Powerkit should have max 0,8 bar reducing to 0,65-0,7 at higher rpm. (Not verified, but a reasonable assumption based on different sources, feel free to correct this one).

The 521HP Turbo S should have max 0,9 bar reducing to 0,75-0,8 at higher rpm. (Not verified, but a reasonable assumption based on different sources, feel free to correct this one).

These are the standards; there are several other factors that may contribute to the actual boost pressure, such as atmospheric conditions, fuel quality and such detected by the engine management system.

The in-dash boostgauge is not known to be very precise so it might be a bit off.

MMMbeer,

Thanks for the feedback. I was reading thru some old Panorama's to get up to speed on the these machines and was reading an article about the differences between the turbo and the turbo S. They list the delta is boost pressure to be .3 bar, for a max of 1.9 bar, which thru me off a bit, I just wanted to make sure all is well.

Thanks

Keith

[acat2002]

Stock boost pressure for the 450HP Cayenne Turbo should be max 0,6 bar which reduces slightly to about 0,5 bar at higher rpm.

The 500 HP E81 Powerkit should have max 0,8 bar reducing to 0,65-0,7 at higher rpm. (Not verified, but a reasonable assumption based on different sources, feel free to correct this one).

The 521HP Turbo S should have max 0,9 bar reducing to 0,75-0,8 at higher rpm. (Not verified, but a reasonable assumption based on different sources, feel free to correct this one).

These are the standards; there are several other factors that may contribute to the actual boost pressure, such as atmospheric conditions, fuel quality and such detected by the engine management system.

The in-dash boostgauge is not known to be very precise so it might be a bit off.

MMMbeer,

Thanks for the feedback. I was reading thru some old Panorama's to get up to speed on the these machines and was reading an article about the differences between the turbo and the turbo S. They list the delta is boost pressure to be .3 bar, for a max of 1.9 bar, which thru me off a bit, I just wanted to make sure all is well.

Thanks

Keith

Since you bring it up....what exactly is contained/included in the "power kit"? how is the boost increased? is there an adjustment on the turbos themselves, or larger turbos(mechanical), or through software upgrades?

Does the kit also include larger intercoolers?

[mmmbeer]

The boost is increased by the engine management system only.

The intercoolers with plumbing are larger for the power kit. Most noticeable are the larger brakes front and rear, but the power kit also makes for a sportier ride because of modified suspension components. Also; cars with the power kit had to be ordered with 19" or 20" wheels as the standard 18" wheels do not fit around the front brakes.

[david_yorkshire]

interesting

mines a std Turbo

peak boost is 0.7 bar

drops marginally at high rpm

[acat2002]

interesting

mines a std Turbo

peak boost is 0.7 bar

drops marginally at high rpm

is yours a 2008 or later?

I have a standard 2008 Turbo and when in sport mode, accelerating from a rolling start WOT, that is about right (7 bar)

how much boost can the 4.8 DI handle before becoming a grenade motor?

I would imagine that the weak link would be drive shafts etc. if you start to push over 550hp.

Not really a consideration for me yet b/c I'm still well within CPO warranty dates/mileage, but when it expires I'd like to have a plan in place to take it from 500hp to well above Turbo S levels. Still, not looking to create a fussy little monster (I will hopefully still be using it as a daily driver)

[david_yorkshire]

nope gen 1 2004 model !

a modern 4.5Litre V8 should easily be capable of over 500BHP, with 2 x turbos strapped to it

I personally think that it's very lightly stressed

hell, my GT3 has only 3.6 litre, normally aspirated, but delivers over 400BHP !

Edited January 2, 2011 by david_yorkshire

[mmmbeer]

There are three main ways of "getting" horsepower out of such a motor; displacement, rpm and boost. The standard Cayenne Turbo is moderate with both rpm and boost which should make for a motor with a relative long life. 600-700HP would not be unthinkable if the 4.5L engine have been set up with high rpm and high boost. But Porsche did not want this.

If the Cayenne Turbo engine can handle increased rpm i do not know, but i do know that Porsche did offer official versions of the motor which had more "normal" boost levels. Cayenne Turbo with E81 power kit have a max boost of 0,8 bar and Turbo S have max boost 0,9 bar. Both of these have larger intercoolers with plumbing. How safe it is to go above these boostlevels I do not know.

And; a 0,1bar difference from the official numbers are well within the tolerances and/or accuracy of the in-dash gauge. So I would not worry about a stock gen 1 Turbo peaking at 0,7 instead of 0,6 bar.

Edited January 3, 2011 by mmmbeer