zenon8890

i just swapped my IHI subaru impreza GT turbo to nissan silvia BB turbo, turbo gives me full boost at 4k on a d15b vtec totally stock and no engine mangment, i'm running at 7 psi right now and the old turbo gave me headachs cuz of the too much tires spining trhough two first gears, is this turbo too laggy for my engine?! would it give me more power at the same psi than the IHI turbo?!

zenon8890

bump

93supercoupe

it will go alot better with any managment

redtop91

The Nissan Silvia had 2 different ball bearing turbos. Knowing what model SR20DET it came off of and/or the exact turbine specifications will allow us to shed more insight on your setup.


Modified by redtop91 at 4:02 PM 7/31/2007

zenon8890

its the first version, i wish that i took a pic of it, but i swapped it fast. whats the differance between them?

redtop91

Sorry about the late reply. I'm still limited to 5 posts per day. The T28 from the Silvia S14 while being slightly larger than the S15 T28 (they're both .64 A/R) is a lot less efficient. The compressor map for the S15 T28 shows that it loses efficiency at a much lower rate than that of the S14 T28 and has a higher flow rate. See?

I don't have the turbine or compressor map for the S14 T28 but it is much less efficient. Spool will be about the same between the two but the S15 T28 is good for about 30-40whp more. It should be noted that this info is provided for the JDM S15 SR20DET. The Australian version of the S14 T28 is the same as the JDM S15 T28. My GT28R (almost identical to the S15 T28) is currently set at 15 PSI and combined with my other mods is making just over 300whp with full boost achieved at the very lowest of the 3k rpm range. If it is an S15 T28 you have an excellent turbo for a mid level power production range.

White Smoke

Since he said "first version" I would assume he was talking about an S13 and it's not a T28 at all, it's a T25. That is a pretty small turbo and 7psi will probably be had around 2800rpm. Max power with the t25 is usually around 235HP on a 2ltr SR.

What year did was the motor that the turbo came off of? Red valve cover?

redtop91

No. It would be an S14/ S15 T28. The T25 off the S13 SR20DET's were not ball bearing. Rather cartridge bearing.