Where did you hear that stock turbos are Garrett 28? The stock turbos for the Cayenne 957/958 is the Mitsubishi TD04. I specifically have the 18T wheel.

 

For real ? Wow mitsubishi turbos on 150k car ? How cool is that ? Lol
Now by 18T turbine wheel you mean that you already have the turbo wheel upgrated like fvd does ? O.o

 

RenaissanceMan,

Interesting that it is only 0.065, I was roughly expecting at least .1 to.15 thickness. That said, based on this information:

2.75" piping has an internal area diameter of 2.62/2 = radius of 1.31"

1.31 * 1.31 * 3.14159 = 5.39" total square area * 2 pipes = 10.78" total square area


So you are indeed well beyond "overkill" for the 8.60" total square area demands of the Turbo S throttle body and manifold!

PorscheCayenne92,

Yes the 2008+ Cayenne Turbos are all Mitsubishi, the stock compressor wheel is a Mitsubishi 18T, the stock turbine wheel is a TD04HL. Each turbo is capable of a theoretical max of around 275-300whp. So far just over 275whp per turbo has already been dyno verified by RenaissanceMan!

Jeff

 

Forgot to also post the calculations for the 2.5" piping (2.37" internal area):

2.5" piping has an internal area diameter of 2.37/2 = radius of 1.185"

1.185 * 1.185 * 3.14159 = 4.41" total square area * 2 pipes = 8.82" total square area

In short the 8.82" total square internal area of the 2.5" piping would basically be enough to meet the 8.60" total square area demands of the Turbo S throttle body and manifold.

Jeff

 

Awesome Kent love it man...glad things worked for the best

 

You have to hit 600 whp with all of your tunning !! Just use 5 gallons of torco accelerator + methanol lol

 

Thanks for the information - always insightful!

Thanks! Special credit as technical consult

Hahaha... looks promising! I am crossing my fingers!!

 

Awesome work RM!

 

That's some amazing skills! Beautiful job

 

Any horsepower figures or times yet?

Was wondering if you would be interested in making another set? If so, PM me.

I am looking for a 08-09 Turbo now and plan on following your footsteps. Love reading your posts... keep up the good work!

 

I just scheduled my dyno session for April 4th, so I will have some final numbers soon. Unfortunately, I couldn't justify the price of the VBox Racebox for just one-off numbers. If anyone has a VBox they want to loan out to me, I would be happy to get some official numbers and possibly even get on the 6Speed Official 60-130mph list

Sorry, the hard part would be getting another set of the aluminum intercooler adapters made economically. Also, I know it does not look like it, but this was a full 5 days worth of fabrication and I did not build any jigs for repeat-ability. Mainly b/c I had no idea how to put it together, but I still do not see the work going that much faster the second time around. I was working in a impossibly tight engine bay.

Thanks! Welcome! I am sure you will love it as much as the rest of us. My mods are done since I am pretty much maxed out for now. So it should be easy to catch up since I am standing still

 

Just wanted to mention that your calculations for cross-sectional area of a pipe are wrong...

You should use radius in place of diameter!

Of course, your comparisons are still valid, but the actual value of the areas calculated in this thread are off by a factor of four.


Just some thoughts... feel free to comment:

The flow in a pipe like this is nowhere near being choked in this application, but it is in the turbulent flow regime regardless of whether you use a 2" pipe or a 3" pipe (yes, I calculated the Reynolds number). Losses by going from one diameter to another will be experienced primarily in the form of a pressure drop if all else remains constant. What does that mean for the engine?

Well, that requires some assumptions. Lets assume that the ECU is looking to achieve a specific boost level and ignoring mass flow rate. This would be how a speed density tune works. Also, assume that the MAP sensor is at the intake manifold and the tune is set for a target boost of 15 psi and that our intercooler pipes are small. Then one could reason that there is a power drop for the following reasons. The ECU will request 15psi from the closed loop boost control system. The turbos will be capable of achieving this and so will meet the 15psi boost demand. Since we have a very small and restrictive pipe, that 15psi will correspond with a comparatively low velocity. That means our mass/volume flow rate would be lower than if we had a larger pipe at the same pressure.

On the other hand, if the ECU looks for a target in mass flow rate (target load) and doesn't care too much about boost level, then larger intercooler pipes will not have much effect on power. This is again assuming the MAP sensor is at the intake manifold. Having a small pipe will again cause a pressure drop, but the ECU will sense the restriction in the form of a drop in mass flow rate. It will then set a higher target for boost to achieve the target mass flow rate. The only loss you will see in this scenario is due to thermal inefficiency of the turbocharger with increased pressure drop. Hotter IATs will make for less power at a given mass flow rate due to the knock limit. For that reason, the larger pipes probably are of some benefit. However, making them out of steel may negate any gains in thermal efficiency.

 

AWESOME Kent!! Reminds me of my beast and my intercooler/pipe setup! great work!!

 

Thanks man! Glad to still see you hanging around. We just have to get you back into another Cayenne

 

loxxrider, thanks for catching my mistake of accidently using diameter versus radius, it is appreciated. Sometimes even the best of us slip up now and then I guess!
New corrected flow numbers are:

Stock Turbo Intake Pipes
=======================
1.843"/2 = 0.92", 0.92" * 0.92" * 3.14159 = 2.66" total square area * 2 pipes = 5.32" total square area

Stock Turbo Throttle Body
=========================
78.27mm = 3.08", 3.08"/2 = 1.54", 1.54" * 1.54" * 3.14159 = 7.45" total square area

Upgraded Turbo S Throttle Body
=====================
84.16mm = 3.31", 3.31"/2 = 1.655", 1.655" * 1.655" * 3.14159 = 8.60" total square area

Estimated Custom Piping
=======================
2" piping = 1" * 1" * 3.14159 = 3.14159" total square area * 2 pipes = 6.28" total square area

2.25" piping = 1.125" * 1.125" * 3.14159 = 3.97" total square area * 2 pipes = 7.94" total square area

2.5" piping = 1.25" * 1.25" * 3.14159 = 4.91" total square area * 2 pipes = 9.82" total square area

2.75" piping = 1.375" * 1.375" * 3.14159 = 5.94" total square area * 2 pipes = 11.88" total square area

Actual Piping (based on a measured 0.065 piping thickness of 16 gauge)
================================================== ====================
2.5" piping has an internal area diameter of 2.37/2 = radius of 1.185"
1.185 * 1.185 * 3.14159 = 4.41" total square area * 2 pipes = 8.82" total square area

2.75" piping has an internal area diameter of 2.62/2 = radius of 1.31"
1.31 * 1.31 * 3.14159 = 5.39" total square area * 2 pipes = 10.78" total square area

The goal here was simply to evaluate the stock piping size and eliminate any potential bottlenecks.

As you have seen from the numbers the combined area of the stock intake pipes is definitely insufficient to meet the demands based on the size of even the stock Cayenne Turbo throttle body, let alone the upgraded Cayenne Turbo S throttle body. Based on the numbers to ensure that you meet/exceed the engine demand thru either the stock Cayenne Turbo or the Cayenne Turbo S throttle bodies you will need to have a minimum of a 2.5" piping.

In eliminating these restrictions, significant power and torque is gained throughout the powerband, and will be evident particularly at higher RPMs as engine demands increase as Renaissance.Man has already detailed.

Regarding the Reynolds number, I was really, really not trying to go that far into the weeds in this discussion. The fact that you even know what it is indicates to me that you have at least some background in engineering. PM me if you want to discuss further though lest we put everyone else on the forum to sleep!

Thanks,

Jeff