Hey everyone,
I have had my single turbo 1jzgte running for about 1200 miles now
Its having an issue where the turbo isnt fully spooling until about 5000rpms, From reading everywhere nobody else is having this issue so i believe it has something to do with my setup
quick list of mods
Turbo has 3" ic piping
Turbo is a borgwarner s300sx3 .91a/r twinscroll
On the back of the turbo i have a reducer it goes from the borgwarner 4.21" to a 3" to fit my exhaust which is straight pipe.It tapers down to the 3" like a funnel
The turbo is also really quiet running even open header you cant hear it whine. Even in full boost you just hear the air sucking in nothing else. Is that normal for a bw turbo?
I have a greddy type rs bov you can barely hear this thing blow off even when i tighten it and loosen it It makes no difference.
The turbo i have has the anti surge housing I wonder if that is what is making it drop pressure to where the bov would be quiet.

I know the reducer can cause lag but would it really be causing this much?
First gear flooring it will only spool about 6-7 psi
second will spool 15 at 5000-5500 rpm
third will spool 15 at 4800
fourth will spool around the same and the same with fifth
I am considering lowering the ic piping to 2-2.5" on the hot side

So besides running a 50 shot, what else would really help with the spool

 

it sounds like you have a boost leak somewhere. what size is the turbo? s360, 363, or 366?

 

Spool / Lag can be a combination of a lot of stuff .

What is the size of the turbo wheels as LoveSCs asked ? is the engine built , what compression or is it all stock , what intake and throttle body , what exhaust manifold (size of runners) , inter-cooler , wastegate size / spring, BOV size ? what fuel .. pump 93 or E85 ? What ECU ? Just too many variables that need to known to determine cause and effect .

Without knowing a lot of the variables , I will tell you though that regardless of some who says the contrary , based on feedbacks of many actual users on SF , a 66mm BW can be laggy compared to the same size of Garrett or Precision though are very reliable. First ,knowing that you have a 1JZ which are 2.5L already has a disadvantage with those having same turbo but whose engines are 3.0L engines like the 2JZ

The performance of a car depends on all the different stuff put together assuming that every part is working properly. Thus every car will perform differently even if they have exactly same turbo.

 

Hey, I forgot to add that I apologize,
Running 93 oct pump gas
stock ecu jzz30 on apexi neo
Motor is stock
Intercooler is 31x3x11
44mm tial wastegate
Not sure what the size of the runners are


Turbo is a 366 Here are the specs

• Compressor Wheel Inducer Diameter (mm): 66mm
• Compressor Wheel Inducer Diameter (in): 2.6
• Compressor Wheel Outer Diameter (in): 3.6
• Turbine Wheel Outer Diameter (mm): 80mm
• Turbine Wheel Outer Diameter (in): 3.14
• Turbine Wheel Exducer (mm): 73mm
• Turbine Wheel Exducer (in): 2.89
• Turbine A/R: 0.91
• Turbine Inlet Style: T4
• Scroll Type: Twin
  
  

 

Sounds about right to be honest. Wouldn't expect much more with the 2.5 and on pumpgas. Are you on a tubalar manifold or cast?

 

Its a tubular manifold

 

for a BW S366 on a 2.5L ... as mentioned above looks normal to me . A lot of users with 3.0 engines are already mentioning the lag the turbo has and surely all the more for 2.5 engines. You probably need a smaller turbine A/R or a smaller turbo , well of course depending on use of car and power goal, so you can determine where you want that power band to be , on the left or on the right .

Just curious , what size of injectors do you have ? I ask since I see you have stock ecu with afc. And how are you controlling your boost ? Is your BOV rerouted in your intake ? What spring size do you have on your wastegate and BOV ? You see all these spring sizes can have an affect on your boost / spool . That is the reason , tough to even say something when you don't have all the necessary information on a setup. It becomes a guessing game which many times I refrain from jumping into a thread when information is missing since one can give the wrong advice which I have seen many times people doing just because they want to say something even with very limited info or facts about the problem.

 

Sounds about right for the turbo set up you have.. Turbo is to big for the 1j. One of my friends had a similiar set up on his 1j and it felt like forever for boost to kick in. I was going to go with the same exact turbo but decided it wouldnt fit in for my goals. Decided to go with the sxe257 turbo. Spools quick and pack a mean punch for that small turbo and its also on a 1j. But i also agree with Gerrb with his last statement.

 

You need a quickspool valve. Trust me.

 

what gerrb said^^^The s366 standard .96ar tends to be a bit lazy on a 2jzGTE due to lower compression. On an a na-t due to the 9:8:1 will keep it awake. A smaller a/r or s360 60mm would probably be of a better spooling rpm range difference. 2.5 displacement has the disadvantage. Also depends on setup all around.