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jebbach911 jebbach911 is offline
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Join Date: Dec 2007
Location: Paducah, KY.
Posts: 112
Turbo upgrades, need advice!

Fellow Pelicanites and Boost Junkies, please help me through these upgrades on my 1991 965 Turbo. I have purchased a Fabspeed header and exhaust system (see pic), a new GT35R Garrett Turbo, a Zeitronics AFR system w/ boost sensor, a cold air intake w/ K&N cone filter, and a 1 BAR spring for the stock wastegate.

I have the headers installed and have adjusted the cold and hot side of the GT35R so it fits where the K27/7200 turbo was. Now the questions:

Where can I get or who should I call about making an exhaust flange for the GT35R turbo? The bolt pattern is smaller even though the outlet port is larger than the K27/7200.

There is a tapped port (1/4 NPT) in the cold side air housing (See pic), what is it used for?

Where can I get a spec sheet/air output graph on this GT35R turbo?

Do I need to run a support bracket from the turbo to the engine like the K27/7200 turbo had, or will the header system support the weight of the turbo without it?

The person I bought the GT35R turbo from tells me I need to put a .040" orifice in the oil feed line to the turbo or the stock system will over feed the turbo and make lots of smoke out the exhaust. Sounds awful small to me, I don't want to starve the oil supply but don't want smoke/blown seals either.

Where is the best location for the oxygen sensor bung for the AFR device? My options are 4 inches from turbo before the muffler or 20 inches from turbo after the muffler. Does the OX sensor need to be in the direct exhaust stream or would it be better to have a longer bung so the sensor is not in direct stream?

Where is the best location for my boost sensor (1/8 NPT male) that goes to my AFR gage? I was going to put a "T" in the IC where my stock boost gage mounts. Is that the best location to read true boost?

The exhaust impeller bolt seems to have been modified/ground on for some reason (see pic). Was this done to keep Joe Public from disassembly or was this maybe done for balancing purposes?

Any advantage to using a TIAL wastegate over the stock one? The stock WG is in excellent condition but I would replace if there is a HP/boost advantage.

I have to cut/modify my oil catch tank to make it fit the GT35R turbo, should I weld in a vent fitting while I'm making mods? The stock one was vented to the airbox.

What is the typical entry point for the AFR gage sensor wires, firewall in front of motor or firewall in front by brake cylinder?

I will be sending my WUR to Brian Leaske for upgrade and RPM switch also, should I do this mod before firing up the new turbo?

Any suggestions for ease of fire-up and tuning would be greatly appreciated!!

1976 911s,2.7, Cobalt blue, G 40 cams, Weber 40 IDA, SSI / Dansk, MSD 6AL
1991 964 Turbo,3.3 ,Polar silver, Fabspeed headers and exhaust, stock W/G, Greddy EBC, Synapse BOV, BL WUR w/ RPM CSV switch, CIS Fuelhead mods, GT 35 Turbo, Snow W/Meth Inj., K&N Cone Air Filter, AAR delete, Decel valve delete, Zeitronics ZR-2 AFR
1994 968 White, bone stock! (son's first car)
Old 08-16-2011, 01:17 PM
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