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View Full Version : turbo switching...should I retune?

nicku
04-21-2008, 01:52 PM
I had a regular s15 t28 (the one doesnt have the divider on the exhaust side) I had it tune with the safc2. And I blew it up on saturday. If I switch to a GT28R the one with the divider, should I get it retune if I dont change anything on my setup
sunnys14
04-21-2008, 02:02 PM
NO

The end.
louisdaboois
04-21-2008, 02:02 PM
you should be fine, as long as the trim and a/r's are the same, it shouldnt flow any different whether it has a divider on the exhaust side or not. imo, you should ditch an safc rom tune is the way to go and fine tune with a safc if you want.
clark
04-21-2008, 02:20 PM
http://i32.photobucket.com/albums/d29/SubaruDude/discopotato.jpg

disco potato!
wvustud2003
04-21-2008, 02:30 PM
i just wish i had either turbo. t25 ftmfl ......
GSXRJJordan
04-21-2008, 02:32 PM
Basically the T28 w/o the divider is a single ball bearing (only on the compressor side), while the actual GT28R (disco potato) with the divider is a dual ball bearing. They flow the same, pretty much spool the same, but the GT28R should last longer. No retune needed.
eclipse_dsm
04-21-2008, 02:46 PM
May I ask how you manage to blew the S15 turbo. Just curious for it may just save your replacement turbo.
nicku
04-21-2008, 03:18 PM
i was driving on highway...i didnt beat it up at all...just regular driving 75 mph on 5th gear...when I got off highway, i wanted to step on it a little bit. There was no boost at all...and checked the turbo....it has bad shaft play. there is no smoke coming out from the exhaust, though. So I think the oil seal is stil good
Silverbullet
04-21-2008, 09:10 PM
Basically the T28 w/o the divider is a single ball bearing (only on the compressor side), while the actual GT28R (disco potato) with the divider is a dual ball bearing. They flow the same, pretty much spool the same, but the GT28R should last longer. No retune needed.

The Disco Potatos are GT28RS and flows about 20cfm more. GT28R is from the Spec R Silvia. Both are dual ball bearing, and both have waste gate dividers. The S14 version (older one, not sure if its also called a GT28R, but some distributer call it that also)is what you are referring to without the wastegate divider.

and ya, you dont NEED a retune unless your changing injectors or MAF or something.
GSXRJJordan
04-21-2008, 09:18 PM
The Disco Potatos are GT28RS and flows about 20cfm more. GT28R is from the Spec R Silvia. Both are dual ball bearing, and both have waste gate dividers. The S14 version (older one, not sure if its also called a GT28R, but some distributer call it that also)is what you are referring to without the wastegate divider.

and ya, you dont NEED a retune unless your changing injectors or MAF or something.

Yes, 'disco potato' = GT28RS not GT28R, but its mostly symantics. I believe they have the same size wheels and housings.

The S15 automatic/non-spec R BB turbo is the same as the S14 BB turbo - no divider, only one side is ball bearing. It is technically called a BB T28, not "GT28R" - that should be referring to a S15 Spec R, dual ball bearing turbo.
fliprayzin240sx
04-22-2008, 12:44 AM
Hell I just went from at T518Z Greddy turbo to a GT3071R .64 and so far i think im good with the same tune. No knocks, EGTs staying low, I got a wide band but I need to datalog it just to be sure. But not having knocks is safe enough for me. (atleast for now).