I know there are alot of people on here that know a bit about turbo selection. For those who need some info on the engine Here are some specs
2.5L 24 valve DOHC 6 cyl rated at 250hp stock
Stock turbo T3 ballbearing (It's really a T28 with a T3 flange)
The turbo has a ceramic turbine wheel and a plastic compressor wheel
Engine has a 9:1 CR
I am looking for somthing that will give me 400-450 BHP on pump gas and even more with race fuel. After talking to my friend who is a DSM guy he recomend a GT40. of course an SC61 uses a GT40 wheel so what do you guys think about this turbo on an RB25? Spool time? I would have to keep boost low at first (8-9 psi) till I get the fuel system upgraded. And one other thing I need to run the turbo with an internal wastegate. What kinda problems will I run into with that?

 

i would recommend a t04e big kahuna for that motor which is actually being setup on a rb25 right now. it has a broad power band and great top end. the spool times will be longer that stoc naturally but it allows for the car to get a bit of tracking when launched and build more time going down the track.

 

if you have some cheeze

gt3040 ball bearing should do the trick, but they cost around $3000

they come with .63 or .82 turbine housing
.70 a/r compressor housing
water cooler center
56 trim compressor wheel (t04s)

and rated 500-600hp

a gt35r is around the same price

ball ball bearing

1.06 turbine housing
.70 compressor housing
watercooler center

and its good to 700hp

sc61 will also do the job with out much damage to your pockets

 

Ok. I think the SC61 is the turbo I want to go with. What kinda lag time can I expect from this setup? Also, How will an internal wastegate effect this turbo?

 

My friend here in Vegas has a RB in his 240, I wanna say he has a T3/T4 on it , Run pretty good

 

external waste gates are better and worth the extra money, internal wastes usually leads to boost creep and spikes,

 

These last 3 replies are all the info you will ever need! So informative!

 

im 2slow4U's hommie.. i have a t3-60-1 on my Rb25 right now and its not too bad.. full boost at 4200.. 4200 is about the lastest you would want full boost to hit.. any higher and i think you will see lag in between shifts since the motor only revs to 6800... if you are planning on going anything bigger i would recomend cams and pnp head to help spool it up..

 

I have read on Skylines down under board that using an adjustable exhaust cam gear you can tune it to bring on the boost a little sooner.
What manifold are you runing cyris? I plan on keeping my AC and PS so I am alittle worried about fitting such a large compressor housing. The SC61 would spool alittle sooner then a T3/60-1 right?

 

yea an adjustible cam gear will help also..
im using the stock one right now with an adapter box to move the turbo a lil further away from the block.. and allowed the add on of a external waste gate... im looking into getting a t4 rear with a .70 ar.. so that i can make a top mount mainifold..

sc61 is a ball bearing turbo right?.. then im sure it will spool up a bit better even tho it is a lil bigger.

 

Hre are some pics of the install
http://community.webshots.com/user/92rb25det

 

The SC61 is not a ball bearing turbo. Ball Bearings are definately better but i dont see the 500+ doollar amount worth it!

 

GT40 is WAY TOO ******* BIG without being built, a GT30 should fit the bill nicely. And if anyone is paying 3 grand for a GT series turbo they are smoking pole. Maybe if you're buying the HKS branded one, yeah.
-PHiZ

 

Well My driveshaft should be here somtime today. I will let you all know how it feels to drive an RB25 powered S13!

 

what mount kit did you use and who made the drive shaft? I have a friend with a 95 240 interested in this swap but doesn't want the overpriced McKinney kit.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PHiZ &raquo;</TD></TR><TR><TD CLASS="quote">GT40 is WAY TOO ******* BIG without being built</TD></TR></TABLE>

I think somewhere I missed where this was going on an RB25det. I think I thought we were talking honda engines. I know NOTHING about nissan engines, discard this comment please. I suck.
-PHiZ

 

The mount kit I used was the OEM Skyline crossmember. I had to make some very simple smal brackets for the tranny mount. Drivetrain.com made my driveshaft. I will let you know how it turns out.