[SOLVED] Low boost and slow spool

Hey everyone!

Im having some issues about my mazdaspeed. Im have really slow spool with my current turbo: BNR S1 Only hitting ish 10 psi at 4000 RPM. Peak boost is 14,5 that about the spring pressure that is hitting. I did a smoke test on pressure so i thought it would be about the same as a boost leak? Everything was tight and i have not seen any smoke coming from anywhere. Never had any problems with my k04 setup hitting 18-19 psi. Now with a bnr s1 and 3 port and having the problems.

My mod setup: Bnr s1, Streetunit tmic, Damond occ, Muffler delete, Catless downpipe, Cobb bcs, Gfb bov, Japspeed tip, Corksport Sri, 2nd cat removed and Autotech hpfp. I have ran different setups of boost control, different setups without 3 port and not getting it work. Max boost is now 14,5 psi with 40% wastegate duty cycle.

 

Can you block off the wastegate vacuum line and see if it free boosts a little bit? As long as you don't go over what you're tuned for it should be alright. That's just to eliminate a fault with the wastegate itself or something turbo related.

Another test is to try and blow some compressed air into the wastegate and see if it moves smoothly.

 

Hey L337 I did some tests. For example we put a vacuum pump on the actuator line and sucked air so if im correct we compressed the wastegate so it has extra pressure so it wont open as easy as it was. Then it boosted quite quickly and hit 17 psi. When we blowed air into the line the wastegate opened at 1 bar = 14,5 psi thats also the spring pressure. I can see in my tunes that from 2,2 psi the duty cycle is 60% already and thats allllll the way untill i let go off my gas.

Im running the 3 port now so should i just top of the actuator line and see how much boost i reach? there is no target psi thats what the tuner told me.

 

Who are you tuning with? There should be a target boost pressure table. Otherwise how will the ECU know if it isn't achieving the requested pressure?

Also you can't really go off of just WGDC alone. If you're incorporating load target tables that will affect the boost pressure. If you're targeting X load and hitting it at 12 psi at that time then the ECU only lets it hit 12 psi. If you are below the target the ECU would allow more boost to hit the load target.

 

my tuner is Justin Heath from the United Kingdom

By the way as far as my knowledge goes... Its tuned by load. So ecu achieves the amount of work that needs to achieve the load. And to achieve the requested load the ecu regulates the amount of psi? or am i talking crap lol

When i look at my logs (load tuned) im hitting the max load at 5200 RPM. I will post a LOG file so maybe it gives some clearance. For my feeling i cant go above spring pressure atm. 1 time when we sucked air out of the actuator line and made a pressure room kinda i hitted 17,4 psi if im correct.

 

Are you tuning with Cobb or Versatune software? He can disable load target and go strictly off of boost pressure target which may get you different results.

Not sure of the time frame since you started having this issue or the weather in your area but cooler air is denser and may be causing you to hit a higher load target with lower boost pressure.

 

Im using versatuner. The turbo is installed not even 2 weeks and had the problem since the start. With my K04 i was hitting 18-19 psi without any problem. First i was hitting 10,2 psi only on 40% WGDC. Adjusted the actuator (was already set on 1 bar) and now im hitting 14,5 psi. so it have a improvement but i heared i should hit way more boost...

EDIT: When i recieved the car the 3 port wasnt set up properly so that should be the reason to bump the PSI

 

You went from a stock K04 to a BNR S1? That's gonna cause you to hit lower boost levels. The S1 is a better flowing turbo than the stock one so it makes the same power at a lower pressure.

For it to hit higher boost levels you need to have the tuner either turn off load targets and run strictly off of boost pressure target or raise the load targets and adjust boost levels to obtain those targets.

 

Yes i went from a K04 to a BNR S1. I do understand the PSI is different because the turbine wheel is different to a K04. 14 psi on a S1 is not the same as 14 PSI at a K04. so for example if he sets it at 18 PSI it should spool quicker and hit 18 psi if thats achievable? Im hearing there are problems with the bcs or actuator or something because it "should" boost way higher and quicker. I did run through the load targets and wdgc tables but dont have to much knowledge about it.

 

The computer doesn't know what turbo is on the car. It simply says I need to get X amount of load reached at Y amount of throttle application or manifold pressure (boost)

If the turbo spools too fast the ECU opens the wastegate faster (more DC) to slow the turbo down. If the ECU sees the turbo isn't spooling up fast enough it keeps the WGDC lower.

All of this is tune related and has nothing to do with the solenoid or the turbo itself. It's about the fact that your current tune is limited by the parameters set in it. As I said tell him to turn off load targets and you'd probably hit the higher boost levels you want. Or he can increase the load target to allow the turbo to hit a higher pressure.

You could put a BNR S4 on it and if your load target is the same it might only hit 7 psi cause it's reaching that load target at that pressure level. Your ECU is limiting the power to prevent an engine failure. It's a safeguard.

 

Im understanding it... thats why my WGDC is already at 60% once im in 4 psi of boost... because its spooling to fast. My buddy has a avarage load of 2,4 and is hitting 21-22 boost. My max load in that log is only 1,6...

 

Correct. There are also a couple of different ways to connect a 3 port boost solenoid. You can do interrupt, bleed off etc.

Here is a diagram of how yours should be connected for an IWG setup



Some setups the DC increases to decrease boost and the other it's lowered to decrease boost. It depends on how it's connected. On my Miata a higher WGDC is keeping the solenoid closed. I generally have it at close to 100 percent so it spools super fast and then immediately slopes down to open the WG.

 

That is how its connected. But i got the message as the tuner and mechanic says the turbo is cooked... thing ran for about 1000 kilometers lol.

This is irrelevant to the issue. Joris just told me he put a vac on the wastegate to hold it shut and the turbo responded in the same way so don't worry about doing the test I just mentioned as this is effectively the same thing. Looks like the turbo is no good from what he explained to me.

Also when i inplug the vacuum line to the wastegate i dont overboost as everyone tells me it should.

 

Have you tried just running the boost reference line straight to the wastegate and see if it makes spring pressure when driving?

The only way I could see a turbo damaged is either by shaft play, chipped blades, a broken shaft, or a crack around the WG flap. That's the only reason it wouldn't produce boost from a mechanical standpoint.

If you block off the WG and don't allow it to open it should free boost. It'll throw DTCs and probably a fuel cut but even for the split second or two if it does you know that it's tune related and not a mechanical condition.

Was the turbo you installed used?

 

Yes the turbo was used from a certified user from another platform like this. Also having contact with him.

Im getting messages from freektune that i should hook up my EBCS 1 Blocked of and the tip blocked off 2 unplugged so a open wastegate 3 boost source from ebcs to turbo

Other option is top nipple actuator > boost source turbo and the ebcs electrical connection unplugged.

As the seller is also following this thread. Here are the videos and photos I asked to see if it had shaft play or cracked wastegate.

 

Btw now I’m hitting 15,5 psi. So that’s 1 boost increase. Nothing insane in my eyes. The more wgdc I get the more boost I should build if I’m asking everyone. I’ll try giving a few rotations on my actuator and see if it changes. A American tuner is telling me the tune is bad and he could solve it.

 

Freektune or purpledrank? Probably Justin and will respectively are amazing, do not go anywhere near dramatune.

Did you re tune for the s1 or are you still on the k04 tune? Because if you're on the k04 tune these numbers do kinda make sense, little off yes so perhaps the tune could be bad and if freek or PD are saying it could be the case I'm inclined to listen to them even @L337TurboZ has said it's a tune limitation

 

Im now having contact with a co worker from Justin brasil if I’m correct. They are saying it’s in the tune. They will make me a tune and we will see if the problem disappears

 

Awesome yeah Justin Brasil is freektune you're in good hands, I've been nothing but happy with my tune from him, let us know if this fixes the issue

 

Tightened down the actuator rod as advice from David but not increasing boost and still slow boost yeah. Would get a basemap this week so really curious