Turbo question???????

[RandyJ 10+ year member]

Example being this, a little drastic, but still holds truth to what I said.

T3 45trim @ 9psi

Max flow is around 15lb/min

T76 @ 9PSI

Max flow is around ~70lb.min.

BIGGG ol' difference.

 

[kuijo 10+ year member]

Example being this, a little drastic, but still holds truth to what I said.
T3 45trim @ 9psi

Max flow is around 15lb/min

T76 @ 9PSI

Max flow is around ~70lb.min.

BIGGG ol' difference.

psi is psi. The guy was asking around how much he thought the engine took stock and we were replying with how much some stock vehicles were running so he could get an idea. And obviously we were close in are assumptions since a stock GN as stated above boosts at 15psi.

 

[marleyskater420 5,000+ posts]

9psi is not that much. SRT-4 come from the factory pushing 13psi...

I run 30psi on stock internals... Its the flow that matters, not the psi.

With that said, his boost should be anywhere from 12-22psi.

Then the turbo he put on probably is internally gated at 9psi. But there are certain things you need to look into. You may not want to up the boost. A PR of 1.61 may be the in peak efficiency island with the turbo selected, as well as providing power is the desired band. Upping the boost may cause problems with flow. Try to find out what turbo it is and we can get you some maps and flow numbers.
And you need to knwoo what you're flowing before you go and buy an aftermarket IC,it would **** to end up losing 4PSI because you chose the wrong IC when you didn't know your numbers, ya know.

If the owner has the gate at 9psi, then he should be slapped. I'd go check it myself and move the puck to make sure it wasn't a retarded owners fault. Then check the vaccum lines to the boost controller, and to the turbo, making sure the boost controller is properly setup. Then check the puck placement on the DP.

 

[IA2 10+ year member]

**** u MarleySkater, I was about to chime in with my opinion, but you beat me to it.....lol. It definitely sounds like the problem lies within the vaccum lines/boost controller/wastegate actuator. He could have a 9 lb actuator, and the boost controller may be allowing the actuator to see a full 9 lbs.....which would make the actuator open and the turbo wouldnt build anything more than 9 lbs. If you dont understand what I am saying, do some research on boost controllers to understand how they operate.

 

[yacob.naif 10+ year member]

Boost's just an easier way to read airflow. Someone said boost is boost, which is 1/2 right. 28psi is twice as much flow as 14 psi ON THE SAME ENGINE. 14 psi on a grand national might be 2x as much flow as 14psi on an srt-4. And 14 psi is out of a t4 is the same as 14 psi out of a gt28r but the 14psi out of the t4 might be cooler, but later in the power curve. Comparing different cars, or even the same car with different turbos is difficult. The only way to figure out what's going on with your car is to actually have it looked at.

Spearco intercoolers are great quality, and one with pre-welded endtanks can be had on ebay for under $300. Aren't there people who run their nationals hot, as well? Never understood oldschool tuning.

Anyways, i'd do a compression and leakdown test before anything, just to make sure the headgasket and rings are in good shape before you start adding boost. Shouldn't cost much at a shop, an hour of labor tops, or free if you can find someone with the equipment.

Good luck!

 

[RandyJ 10+ year member]

psi is psi. The guy was asking around how much he thought the engine took stock and we were replying with how much some stock vehicles were running so he could get an idea. And obviously we were close in are assumptions since a stock GN as stated above boosts at 15psi.

Sure, the outlet PSI being the same on each turbo means, the outlet PSI is the same, but you cannot rightfully say that 9psi at the outlet of a RHB25 and 9psi at the outlet of a turbonetics Thumper is going to yield the same result, can you?

If the owner has the gate at 9psi, then he should be slapped. I'd go check it myself and move the puck to make sure it wasn't a retarded owners fault. Then check the vaccum lines to the boost controller, and to the turbo, making sure the boost controller is properly setup. Then check the puck placement on the DP.

Are you saying that regardless of the turbo, he should not have it gated at 9psi? Or the stock turbo should not be at 9psi.

 

[spudracer326 10+ year member]

don't the wrx evo srt-4 all come with around 15psi stock? or closer to 1 bar

they are 19pounds till 6500rpm then taper to 16 to redline for the evo...i beleave the wrx sti is about the same....the standard 2006 wrx only runs around six with the new 2.5litre motor

 

[spudracer326 10+ year member]

with a larger turbo you dont neccesarly need to be running higher boost...but nine doe sound low??

 

[marleyskater420 5,000+ posts]

Boost's just an easier way to read airflow. Someone said boost is boost, which is 1/2 right. 28psi is twice as much flow as 14 psi ON THE SAME ENGINE. 14 psi on a grand national might be 2x as much flow as 14psi on an srt-4. And 14 psi is out of a t4 is the same as 14 psi out of a gt28r but the 14psi out of the t4 might be cooler, but later in the power curve. Comparing different cars, or even the same car with different turbos is difficult. The only way to figure out what's going on with your car is to actually have it looked at.
Spearco intercoolers are great quality, and one with pre-welded endtanks can be had on ebay for under $300. Aren't there people who run their nationals hot, as well? Never understood oldschool tuning.

Anyways, i'd do a compression and leakdown test before anything, just to make sure the headgasket and rings are in good shape before you start adding boost. Shouldn't cost much at a shop, an hour of labor tops, or free if you can find someone with the equipment.

Good luck!

Most GN's are cold air. Duttweiller started with us, and then moved to LS1's..most people don't realize that.

Anyway... most of the DIY LS1'ers and GN guys are starting to use OBX ebay IC's because they work halfway decent, and are cheap...and I think there should be a kit out now for piping as well.

It should take him one pull of the finger to know if the boost is set at 9lbs. Once he does that, then we can start eliminating everything else.

Nooblet- Yes. No GN turbo runs well that low. Most turbos work from 23-40psi, all because of our head restrictions.The stock turbo is set to 13.5psi, and the GNX is 15.

 

[dbhittin 5,000+ posts]

my car is 12psi stock and im runnin 16 now and 20 when i get my fuel pump next week.. and yea it depends on the turbo... 15psi on a T3 *example* will give me more airflow and power than my stock 14b at 15psi.. also depends on your comp ratio.. mine is 8.7:1