BOOST QUESTION PLEASE! FOR BOOST GENIUSES TOO!! need advice

thegremlin

New Member
:)HOW YOU DOIN? i got a 2000 gsr that i want to boost completely stock.... well heres the thing she gets driven daily about 45 miles give or take.
i want to boost my car with stock internal with about 8-9psi enought that i can make 250ish or so.. but i want to keep it safe for daily driving ( i go to school and work) [I]eventually maybe by november or so then do some internal work, but for now stock![/I]

i currently got a good log manifold, 450 dsm injectors, a p28 ecu, intercooler, and jumper harness

heres the thing....currently my friend is selling me a garrett ball bearing GT3071R good for up to 440hp here are the specs...
The Dual Ball Bearing GT3071R Turbo comes assembled with T3 style turbine housing with T3 inlet flange. Turbine housing style is an optional GT housing with ATP turbo V-Band Flange. Compressor housing is T04E frame size with 2.00 outlet. Compressor inlet is 4.00 inlet.



Turbine

-Wheel: 60mm w/ 84 trim

-Housing: .63 ar

my question is
Compressor

-Wheel: 71mm w/ 56 trim

-Housing: .50 ar


:shock:
1. do you think this turbo is too big for me?
2. But can i use it for now?
3 will i have too much lag
4. what you think i will spool at?

:roll: i really hope i can buy buy the turbo becouse im getting a really good price:D
 

Aussie

Zoom-Zoom
Well I'm not a genius but.
1. not really
2. yes
3. not really
4. with a log manifold, depending on piping size for your intercooler, etc, 3500 probably.
 

dc2GS-R

Super Moderator
thegremlin said:

1. do you think this turbo is too big for me?
2. But can i use it for now?
3 will i have too much lag
4. what you think i will spool at?
Click to expand...
I'm not a genius either but...........

1.) Yes. If you are only shooting for 250whp then a turbo sized for 450+hp is a little overkill
2.) You could possibly use it now, but I would do some calculations and make sure that running that sized compressor at such a low rate won't put it on the surge line of the compressor map. You could also find a much more efficient turbo for your application as the GT3071 will probably not be on an optimal efficiency island of the compressor map at that flow rate.
3.) I don't think it will lag too much because all of the Garrett GT series have incredibly fast spool time
4.) I'm not doing the math to find out exactly what this point would be, but it should be a tolerable amount.

I do think you would be much better off if you got something in the GT28 range.
 
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thegremlin

New Member
dc2GS-R said:
I'm not a genius either but...........


2.) You could possibly use it now, but I would do some calculations and make sure that running that sized compressor at such a low rate won't put it on the surge line of the compressor map.
3.) I don't think it will lag too much because all of the Garrett GT series have incredibly fast spool time
4.) I'm not doing the math to find out exactly what this point would be, but it should be a tolerable amount.

for comment #2 im a little new to the turbo game:???:... i am sorry to ask a dumb question:oops: but what is surge line on the compressor map mean? and how would i make that calculation?

i would greatly appreciate ANY advice that you caN give me...:)
Click to expand...
 


dc2GS-R

Super Moderator
Surge occurs when the compressor is too large for the application. During surge, the turbo operates on an extremely low efficiency and causes airflow instabiliy that can cause erradic boost and also wear the turbo extremely fast.

These are some good reads that have a lot of useful information

Garrett Turbo Tech 101 - Basic turbo knowledge
Garrett Turbo Tech 102 - Intemediate
Garrett Turbo Tech 103 - This involves compressor maps and and formulas to use to properly size a turbo to your application and needs
 
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patrick4588

Integra God
people run t3/t4 57 trim and 60 trims all day long on stock gsr's. they are good to 500hp. i think you would be fine with that turbo.
 


dc2GS-R

Super Moderator
patrick4588 said:
people run t3/t4 57 trim and 60 trims all day long on stock gsr's. they are good to 500hp. i think you would be fine with that turbo.
Click to expand...
They do, but I also think they are dumb for doing it. I've never understood the reasoning behind why so many Honda owners run vastly oversized turbos. It doesn't make any sense. Running a properly sized turbo will be more efficient, make more power at the same pressure ratio and spool faster.

I'm not much for stereotyping because it's usually pointless but this seems to be a common thing with Honda people. Buy a turbo capable of 500hp to make 300hp while running dangerously close to the surge line and operating on one of the poorest efficiency islands of the compressor map

I just don't get it :what:
 

patrick4588

Integra God
the 57 trim isnt that inefficienton the lower boost levels. i remember when i was doing my first turbo build on the stock motor and it was in a pretty decent efficiency range.
 

Winki

Undercover mod
Well if there is a good tunner he will make more than 250 on 9psi but either way the turbo will be fine and work well. wether its the best is a whold nother topic.
 

thegremlin

New Member
wow guys you guys give great advice !! but im not going to lie im a little confused on what to do :eek:(
i dont know if i should yuse this turbo or not
 
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