powdrhound

Nothing is alarming. As I said above, output is "capped" due to the simple fact that the airflow capacity of the MAF is maxed out. The engine and turbos could flow more air up top but the MAF can't measure anything above 1450Kg/hr if I recall correctly. As such, that becomes your ceiling.

TeCKis300

While the K16-24 likely makes a great street turbo, Porsche does know a thing or two in regards to the straight K24s.

Low rpm tractability is not the priority for race cars. The overall larger turbo is therefore optimized for better overall volumetric efficiency at high rpm/high power. It will be able to sustain that power for longer durations without excessive turbo shaft speed, heat in the turbo, IAT, and engine.

Kevin

TeCKis300, you do realize that the 3.8 liter 997.2TT has KO4 installed (smaller than K16).. This same turbocharger is fitted on the 997GT2RS (KO4's).. In fairness it battles high shaft speed, and heat... IAT are reduced due to a more efficient compressor stage vs K24's..

TeCKis300

You're right. Technology marches on with better materials, aero of the compressor and turbines wheels, and VNT.

Do those K04's use a ball bearing center section too?

Kevin

No, ball bearing.. Infact, it's a single stationary bushing vs the typical full floating dual bearing arrangement. Operational speed to 200K

996tnz

Kevin's advice will be spot on as usual and a K16/24 will be the better tool for the job. That said, having raced one of Kevin's 1 Bar stock K16 tunes on track to the point of blueing the exhausts, as well as having taken it on a summer rally tour with about 250 miles of tight twisty tarmac special stages I can say that your on-ramps and passing runs shouldn't worry it at all.

We were pushing hard on that trip on closed roads for 20 or 30 minutes at a stretch eight times a day for three days running. She was about the only one not on r-comps, running with a group of 991 GT3s, Gallardos, R8s, GTRs and a hotted up AMG C63 with all of us aiming to hit 100 mph between the stacked corners, but the 996 Turbo just took it all in its stride.

She's around the 500hp and just to be clear, knowing my intended usage of the car, I added a free flowing exhaust and enhanced intercooling to the UMW base package but they'd only be nice to haves for just general road use (though the exhaust does add power too). I was looking for a street optimised car that would still do well on track, rather than one more track specific and we also get into regulatory issues where I live if we swap out the turbos.

Whichever way you go, you can't go wrong with Kevin and you will fall even deeper in love with your car.

996tnz

By way of illustration, this would be the least twisty special stage we ran, and I can't see you hammering your car harder for longer than this on public roads that aren't closed for motorsport:

http://www.dailymotion.com/video/x2r27uh_911-turbo-rally-ss-16-wiltsdown-nz-targa-bambina-tour-2015_auto
You'll notice the pace drop a couple of times there though, as the leader was slowing off a bit now and then to cool his own (naturally aspirated) engine.

powdrhound

I have a set of Kevin's custom K16 zero clearance turbos and after two seasons of hard track use (those who know me know what I mean by hard track use) and they have been absolutely flawless. My exhaust is heavily blued so there is some serious heat going through the system...
The key to longevity on these or any turbos in my opinion is a nice cool down period after the car is run hard. I always allow my car to idle for at least 10 minutes before shutdown after each track session.

Ffndarmy

I am very interested in this!

Justin Henry

2004 996 TT. Looking at doing a Turbo upgrade still something you do. Please give me a call.
justin
720-217-7838


You do NOT need to purchase a set of K24 to build a set of K16/24's... I have all the conversion compressor wheels and machined compressor housing in stock.[/QUOTE]

"02996ttx50

16/24's are the shizznit.

2fcknfst

This is an interesting topic as I was considering going to a newer style k24 for my x50 - now, I am unsure of which way to go...

Rvca3112

911mhawk

I went from stock k24s on my X50 to Kevin's tune 2 weeks after I bought it and the car was fast enough for about 6 months.
Then I got his k16 Zero Clearance turbos, fueling, inlet tubes, ICs, and WOW, total transformation of power delivery.
As a customer, Kevin has been a great resource and lots of help.

Kevin

The K24 compressor wheel/compressor housing mod is a great "factory" upgrade. It's amazing how old this thread is and how time has flown by.. For street driving and aggressive canyon drives the K16 hybrids are hard to beat.
Porsche continues to rely on "small" turbine wheels/larger compressor wheels found in the 991.1TT/991.2TT and new 991S or GTS..