Guys I guess will go Gtx2867, they are like the latest A28 turbos using HTA68 wheel, I already have the headers and external WGs so guess will be cheaper to go GTX over A28s

My headers are T3 but I can "convert" them to V-Band if necessary.

My last question is what would be the A/R to choose for these turbos considering will run mainly at low boost 1.3bar or so for 90% of the time and would go high boost from time to time.. My setup can maximize easily any gt28 based setup, so maybe 1.9-2.0bar guess should be where they will be over

I saw .64 having a lot of benefits (much better torque and hp) till 5000rpms and over that the .86A/R doesnt gain too much, on the other hand TIAL recommends the .86 A/R... dont know what to do, any help?

 

I'd go with the bigger exhaust a/r myself (Doesn't Garrett make a .82 T3 side?). You'll be able to use more the compressors efficiency. But sounds like for your setup, you'd be happy with the smaller a/r as well. You already have the T3 flange so you could start with that and if you want to push them more, go with the TiAL housing and convert the flanges to v-bands. It will more initial work with the TiAL option I'd imagine...and more expensive.

 

Exactly this is the plan, to try the 0.63 T3 and later on if in need for more power will switch to either .82 T3 or .86 vband

Anyway my setup should help a lot the turbos as running 4.5" ICs, big intakes, 3" free flow exhaust, meth kit, etc... 800hp would be ok, car will be very low 3200lbs without gas and driver

Having 1bar of boost before 3500rpms is what I want now for the track, I have a Cayman Cup to beat first and then move on to 458 Speciale territory

 

If you are on a windy tight track just keep revs up.. you should not have too many problems with any of the cars you mentioned

 

The turbos I run now hit very hard, cant drive easily the car even @0.8bar, have to keep above 5500rpms or drive in a higher gear... driving is like the old 911turbo water cooled, still fast but can be faster.. a lot of fun (work) to keep her on the track, but can be done easier with smaller turbos

Those 458 speciale are very fast on the track, no way a lightly modded 996tt even to keep up with them, 605hp and less than 1300Kg dry... ninja transmission, advanced traction control, slicks, etc..

 

Fadi

I have a few cousins who were famous V8 drivers

Philosophy =

1. If slower put the faster cars into the wall
2. If quicker = see 1.

 

LOL best psilosophy I heard of

Ordered GTX 2867 A/R .64 T3 as my headers have T3 flange, considering even bigger A/R later for more top end if spool will be ok and still in need for more power, but I guess should be fine for my new goals

My time now at the local track is 1:42.4 with pass and full tank on these big turbo setup, looking to install the gt2 seats, remove (again) the back seats,etc... get some more practice along woth fresh R888s and hope the GTX28 will help me cut 7 seconds or more... 1:35:xx is my first goal

There is a Cayman Cup LeMans edition on slicks running 1:35 here and a 997gt3rs on slicks too did an amazing 1:33.5.. track is slow and these NA cars might be overall faster as our Turbos dont have time to get into their sweet spot
Best time is 458 challenge 1:28 (pro driver)

I am working on a greddy switch now to get high boost on the straight line to recover at least one second using this mod, wanted to do a gearbox switch - low boost till second gear and high boost starting 3rd gear, but this seems to work just for drag or roll racing.. in this case will be complicated and might just use a BIG red switch instead

Will let you know my thoughts after trying these turbos... this is already the 4th set

 

Sounds to me like a standalone would be a very wise investment, for solid boost control and safeties if nothing else.

 

Had a syvecs but sold it, regarding safety there isnt a big concern as will run mainly low/mid boost with decent low timing, nothing crazy

greddy has a remote boost switch, asking 100+ $ for it, but they arent selling it anymore anyway, building a switch will cost me a few $ only

 

Ended up with gtx2863 t3 header and .64 garrett housings, vband exhaust 2/5", looking forward to put them on, unfortunately the gtx2867 werent on stock for a long time and decided to go one step smaller, even they are a better fit for a 3.6L stock cam and 7250rpms redline than the 67s regarding track performance

As Hydra said, they are the perfect fit for my stock like engine (no heads work, stock piston with rods and studs), please see attached pic, there is also the old gt2871 small trim48 and 1.8L engine plots

After my calculation and considering just 0.9-0.93 efficiency the engine will flow 42-43lbs @7000rpms @29psi and about 44lbs @7500... So the turbos should be able to feed the engine till 6800-7000rpms or so, considering the turbine will be able to evacuate properly

Anyway I expect 24-25psi (1.7bar) to be the sweet spot for these turbos with some decent timing on 93pump+50meth, anyway the free flow exhaust, big ICs, big intake....should help.

Going back to 4WD as want to use MPS Cups 2 and they are available on stock sizes, also I got a great price on MPSC2s @996tt sizes compared to R888s @996gt2 sizes

By the end of next week I should be able to share some impressions follwed soon by new dyno runs, if reaching 600hp crank @1.3bar and 750+hp @1.7-1.8bar and keeping the boost up on top but with the best spool down, I would me more than happy

 

These turbos should be able to create positive boost @1600 rpms

 

use a RPM based boost controller and ramp in boost like Porsche does on Gt2 from factory instead of hitting it all of it at 3500 rpm. these turbos are gonna come on so hard you wont be able to keep it on the road in corners.

 

Hey Mark! running just an old but reliable profec specII now, will try first to see how it feels, if going to change the EBC was considering a Plex or newer version of HKS and have also boost by gear as both street or road racing it helps a lot.

Any EBC would you recommend ? Read a bit also about Apexi

Coming back from 4600-4800rpms full boost turbos didnt even considered will have a problem like this

 

i was using HKS on 997 to accomplish this and it worked flawlessy. PLEX is great too.

 

I would run 100% meth with these turbos at 1.7 bar on a stock motor. That's the only thing that kept my motor intack running same numbers. Highly recommend boost by gear, I was break Hoosier R6's 345's 1st through 3rd gear. Looking forward to your numbers.