Gtr35r 0.63 Or .86

[scarface]

hey, just need some advice on wat size exhaust housing is more suitable for a gt35r, its for r33 rb25, engine has stock internals but has all support mods, i've heard that the 0.86 comes onto boost at about 4000 and i'm pretty happy with that, but just want to know when boost comes on with the 0.63 housing, thanks

[Adriano]

hey, just need some advice on wat size exhaust housing is more suitable for a gt35r, its for r33 rb25, engine has stock internals but has all support mods, i've heard that the 0.86 comes onto boost at about 4000 and i'm pretty happy with that, but just want to know when boost comes on with the 0.63 housing, thanks

Ive fitted a .63 to a stock rb26, it made 327rwkw at 18psi, and 309 at 16psi. comes on at about 3500

[scarface]

thanks for that mate, so on an rb25 boost would come on at about 3500 as well then, i've heard that it can come on real early at liek 2500 which is why i was leaning more toward the bigger housing, does the 0.63 choke the turbo up top as i want something that pulls hard to redline, i'm not too worried about lag if it's going to kill my topend

Edited September 26, 2007 by scarface

[Al]

The .63 would be my choice on an rb25.

[murrayis]

would definetly choose the .63, if it was a built motor and you wanted more top end and didnt mind a bit of lag then go the .86

[HypeR33]

I have the .86 and it isn't too bad peak power at 6850...full boost between 4k - 4.5k. 306rwkw @ 15psi

***edit*** make that full boost a bit before 4.5k rpm

[zebra]

HypeR33 - What does it ramp up like? Light switch or does it come on smoothly?

[HypeR33]

HypeR33 - What does it ramp up like? Light switch or does it come on smoothly?

its pretty smooth...there is a pretty big jump in acceleration and keeps on going past redline. I went for the bigger exhaust housing so that it was a bit more subtle and not a off/on boost transition. Still a lot of fun to drive

[zebra]

Thats not a bad curve, Id still want mine to come on at around 3500 as I've got stock rods and dont wanna rev past 7k rpm (my limiter is at 6900 atm) But then again im not chasing as much power as what you've got, and ive noticed that yours noses over at 7000. I want a 'more tractable' street engine i guess you could say

Edited September 26, 2007 by zebra

[fantasy]

Thats not a bad curve, Id still want mine to come on at around 3500 as I've got stock rods and dont wanna rev past 7k rpm (my limiter is at 6900 atm) But then again im not chasing as much power as what you've got, and ive noticed that yours noses over at 7000. I want a 'more tractable' street engine i guess you could say

It's all personal choice but would be using the .82 A/R rear housing.

[zebra]

Im gonna go .82 but on a smaller GT30 seriers turbo

[HypeR33]

Thats not a bad curve, Id still want mine to come on at around 3500 as I've got stock rods and dont wanna rev past 7k rpm (my limiter is at 6900 atm) But then again im not chasing as much power as what you've got, and ive noticed that yours noses over at 7000. I want a 'more tractable' street engine i guess you could say

Thats on a stock bottom end It now hasn't been tuned for 18 months, so I am thinking its about time for a tune

[scarface]

yeah i tihnk im going to go with the bigger exhaust housing, rb25's are tough and with a good tune should be able to handle 300rwkw, have a mate with a to4z on a stock rb25 and its been running fine for almost a year now, puts out 340rwkw i think.

is there any people who have experienced the 0.63 housing??

Edited September 27, 2007 by scarface

[3wilson3]

have a friend with a .63 on his GTR and all i can say is.. im glad its not 2wd. no chance of traction.

but maybe thats what you want

[RB30-POWER]

this thread isn't to bad if your interested in getting an idea on power outputs from gt35 turbos

http://www.calaisturbo.com.au/showthread.p...;highlight=gt35

[Al]

Thats not a bad curve, Id still want mine to come on at around 3500 as I've got stock rods and dont wanna rev past 7k rpm (my limiter is at 6900 atm) But then again im not chasing as much power as what you've got, and ive noticed that yours noses over at 7000. I want a 'more tractable' street engine i guess you could say

Then buy a HKS GTRS

PS: Tomei Poncams. Head porting, std bottom end.

With a std motor, the turbo may come on boost a fraction earlier but make a little less power in the mid and high range: Expect peak at 250rwkw, as an estimation.

PPS: Ignore the RED line, tested a different exhaust

[Al]

this thread isn't to bad if your interested in getting an idea on power outputs from gt35 turbos

http://www.calaisturbo.com.au/showthread.p...;highlight=gt35

Not real a good indication considering the VL's have a 3.0ltr engine

[RB30-POWER]

yeah true, but they have a lower static compression ratio and sohc/smaller ports, so kind of puts them lineball at the end of the day.

the point i was getting at, is if your not planning to make that sort of power, why not run a smaller turbo or housing to reduce lag where possible. no use having extra lag if you only want to push it 50%

[zebra]

Al - When I said a more tractable street engine i meant around 20-30kw short of what HypeR33 has. I dont wanna go to the effort (re:cost) of changing cams where's the turbo ive chosen will give me 250rwkw easily on lowish boost and would (should) have a nice progressive torque curve. I just want a lazy engine which on low boost will pull cleanly to red line without being like a light switch or having everything down low and run out up top.

HKS Gt-RS turbos are great but in my opinion they are just too physically small for the RB25 - especially when you look through the RB25 Turbo Upgrade thread and guys with High-Flows Are getting better results than those with the GT28 sized HKS/Garret Turbos.

But Anyhoo i think ive hi jacked this thread enough

[croat]

i have a 0/83 on my rb25. very good match in my oppinion. makes peak power around 6500 and full boost by 4-4.3k