Question about GT2 Turbos...
 

I have been searching this forum and reading as much as I can regarding the GT2 Turbos... My understanding is that they are KKK K24/16's ? Is that correct? If so, what are the practical limits to these Turbos in their stock configuration in terms of the boost they can be used at (i.e 1.0 bar, 1.1 bar etc) and what RWHP levels can they support on crappy California 91 octane? At what point does it make sense to upgrade the compressor side to an 18 or 20 and then at what point do I just scrap them and go to a completely different Turbo setup?

Any and all ideas and opinions would be greatly appreciated, as I am looking at upgrading my 2003 GT2 to approximately 650 FWHP/ 575 RWHP and I'm looking for the best way to get there without dumping $15K into it.

I am thinking: exhaust with 100 cell cats, 5 bar FPR, injectors, Intake system, plugs, tune from either protomotive or EVOMS, blowoff valves and upgrading my existing GT2 turbos with a new compressor wheel from Markski...

They are K24s (not hybrid K16/24s). 1.1 or 1.2 bar with good gas is all you want to do with those. I wouldn't do blow-off.. keep to a recirc style DV.

To get to 650whp I think it will be tough to do so without spending $15K thats just my opinion. You drive a GT2 so I doubt you are going to want to put anything but the best available on your car. To get to 650whp will take a 20G conversion. You can contact Blouch Turbo or Protomotive for the cost of modifying your existing turbos. The rest is all dependent on which of the great vendors you choose to use. I've had great experiences with everyone I've used.

Thanks for the info.. I actually think 550 - 575 RWHP is what my goal is.. 650 RWHP might be too much for my purposes...

Just fyi... I just put 18G turbos in my car and added meth. Car dyno'd 553.9 whp. I'm assuming you don't want to mess with meth, if you sent your turbos in to blouch or proto, the cost for the upgrade to 18G and 20G would be the same, so you might as well go 20G and that should get you pretty close to where you want to be (with a new tune of course). I didn't upgrade my injectors, and i didn't even change my airbox, so you shouldn't have to do much more either. All in, probably around $1200 for 20G upgrade, $2k for new proto tune, plus labor/install... oh, and 5 bar.

This is a concept that very few of us are able to grasp anymore. I think the man for the job in your case is Alex @ Sharkwerks, who posted above. He has done a bazillion cars in the bay area all with great results and satisfied customers as far as I've ever seen. I'm sure he can come up with some sort of program that will fit your budget and your desires.

Good luck and hold on to your wallet. It is a slippery slope. I don't even carry a wallet any more because I don't have anything to keep inside of it! hilarious

The 20's would be chocked pretty significantly without some sort of airbox/intake modification as well as fueling. The GT2 intercoolers are bigger than stock but i'm confident they wouldn't be adequate for the 20g's. The 20G's would also certainly require a new clutch. The 18g's are the best budget setup and allow for incremental growth. The 20g require an extensive line up of modifications.

Skarky or Evoms both have a great solution to what you are looking for.

You beat me to it! i was just about to say, you will need a clutch... and come to think of it, everyone who has the 20G set up has gone push through set up and injectors... 18G is definitely the best deal for the budget spender.

I want to make sure that I have plenty of midrange.. I don't want the power to be all up top and have to wait for them to spool up...

Thanks... I have been down this road many times and want to keep a lid on things with this Car.. I had a 550 HP 944 Turbo, built by PowerHaus (Todd from EVOMS was working there at the time) The Car was in a 7 page feature in Excellence Magazine and ended up as 80% track 20% street but became too much for everyday use. I want to keep the GT2 as a 90% street, 10% track Car and with 550 - 575 RWHP, it should suffice...

I will visit Alex at Sharkwerks and sit down with him to discuss options... I already have a triple adjustable JRZ package going on the Car for suspension upgrade and need to address the engine now.... :) I will also go to the guys at S CAR-Go in San Rafael, as I understand they are affiliated with Protomotive and see what they recommend.

Stock k24s on your GT2 will not give you 650 fwhp...
the best thing to do is a 18g upgrade with a little extra secret done to it... you will be happy for a while...

For the power you're talking about I think the 18g is for you. I had one and it's just about a perfect setup for the street especially when you factor the cost into it. I couldn't tell much difference (maybe 300-500rpm) in the spool between my flashed K16s and my 18gs. The K24/18g is a very strong, reliable and proven setup.

Thanks for all the input guys, it's much appreciated.

The 20's spool very quickly. I've had both the 18's and the 20's and I'm almost willing to say the 20's spool even faster. A well put together 20g setup is going to cost in excess of 15 grand though in my experience. 18g's can be done for around 10 as the clutch isn't always necessary immediately. If you are doing injectors in addition to the 18's i'd do the clutch while the motor is dropped.