Intermittent Performance

[Kinkstaah]

... 1) isn't the answer because Lith asked two different things..

What is controlling boost/map pressure/load when you are driving around on the street?
You can't really tune over what the ECU is seeing, unless you fudge the numbers and have the same timing/fuel at 24psi that you do at 21psi. This is really very bad for both possible boost settings, or it's perfect for one of them, and really bad for the other one.

There is an argument that when it's set to 24psi you are never at 21psi at 7000rpm, or at 21psi at 5000rpm, so you can use those cells on the map to tune for 24psi but.. yeah...

The best way to test this is actual testing, to confirm whether it's in your head or not. Phone app of some sort would be ideal to do a few back to back runs on a deserted (private) road. Especially if it "feels bad". Cars aren't ever truly intermittent.
 

[No Crust Racing]

Sorry if I misunderstood? 

Haltech is the only Map sensor in the car, it controls a mac valve connected to both waste gate actuators. 

Not sure if I'm missing something else here? 

[Lithium]

Those are kind of the answers I expected though to be fair it's hard to know what is definitely going on - I obviously have my suspicions.

I should have asked a 4th question, do you have a separate boost gauge to show you what boost you are actually running?

My experience with tuning on the dyno is that it is really easy to get a consistent boost curve as the conditions will be consistent and the engine will always "pull" through the rpm at exactly the same rate.   Because the car is always following pretty much the same boost curve, it will also seem like the tune is perfectly on point - so it'll seem like you have got away with mystery tuning and getting a solid tune, however that may not be the case in the real world.

The first thing I'll suggest is entirely possible to be going on is that you aren't running the same boost curve on the road as you were on the dyno.  Internal wastegates can be notoriously finicky and often need varying inputs from the ECU/boost control solenoid to be kept on track - this is why we have closed loop boost control and why tuning the base duty cycle tables can sometimes be a fine art, this is particularly the case when you are running a fair bit over gate pressure.  Targetting 24psi when running 1bar actuators would fit well into that category, imho.

The trick here is that the ECU can only see "21psi" so god knows what it thinks it's doing when it's trying to control boost, I have no idea what the tuner would have done with the tables but I can only assume that it's utilising a fixed duty cycle for anything over 21psi to try and maintain "24psi" and there will be no adjustment if it goes over or under 24psi.  This means you could potentially be overshooting or undershooting your 24psi on the road and the ECU will do nothing at all about it, so you have the very real possibility of running mystery boost!

That all by itself could cause a certain amount of what you are talking about, as you have said yourself - it feels like it's running less boost, but wait... there is more....

If the tune "looked fine" at 24psi on the dyno, that means that the timing and fuelling is mint for 24psi.   What this means is that if you end up hitting only 22/23psi then the timing and fuel is retarded and rich for the boost levels you are actually hitting.   But wait, there's still more!   What if you overshoot 24psi?    That could get much more exciting.

What I can guarantee is that the transient areas between 21-24psi will be different in real life than on the dyno, so who knows what has been done to cope with that.   I'm guessing it'll always feel slightly flat in that range before it hits your boost target IF it is actually successfully and consistently hitting the target boost.  I honestly don't want to wager how likely that is.

Just a thought, anyway.

Edited March 20, 2017 by Lithium

[No Crust Racing]

No extra boost guage, not forking out the many dollars to get the Nismo MFD upgrade and don't like additional gauges. 

Am sourcing a map sensor now and will go to closed loop when it goes back in for cams and springs. 

Appreciate the feedback

 

[No Crust Racing]

Is there anything special about the Haltech sensor that warrants 3x the price of any other universal sensor? 

[Dose Pipe Sutututu]

20 minutes ago, ActionDan said:

Is there anything special about the Haltech sensor that warrants 3x the price of any other universal sensor? 

no... and also they already have their scaling determined however it's not rocket science to determine the max and min vs max and min of pressure as the output is linear and not exponential like temperature sensors

[No Crust Racing]

Waiting on tuner to give me the price he can get the Haltech one, as he gets better prices. 

Otherwise, any issues with this? 

http://www.ebay.com.au/itm/151315040163?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Probs just grab the Haltech one n the end, but nothing wrong with having a backup plan. 

 

[turb33gtst]

Noticed one of your posts where you posted a picture on another subject , your still running stock Fuel regulator

an adjustable regulator might be a good idea if your going to run high boost setting.

[No Crust Racing]

Why? Stock regulator is fine at this power was my understanding? 

1000cc injectors and 460lph pump. 

 

 

 

[Hadouken]

Stock reg is fine.

No 1 diagnostic tool for turbo car is a boost gauge.

No 2 diagnostic tool is a AFR gauge.

[No Crust Racing]

Dont want an additional gauge cluttering the interior. 

Will get map sensor then just use ECU manager to do some diag runs and review boost. 

Already have wideband. 

[burn4005]

you didn't melt your cat away from the housing when you were doing anti-lag shenanigans and now its rattling around sometimes blocking the exhuast?

[No Crust Racing]

Haha, nah, it won't be that. 

[Hadouken]

Is possible

[No Crust Racing]

No, it wont be that  100% certain the cat is fine. 

[Piggaz]

[No Crust Racing]

I've seen videos, but I've never personally fisted a pussy..

[NickRB20]

Wouldn't be something silly like a blocked fuel filter?

[No Crust Racing]

New when I did the fuel system upgrades, but I have heard that when switching to e85 you should replace it after a few thousand k's as e85 tends to clean the fuel system out of shit. 

Can't hurt to grab one as a spare when it goes in. 

[turb33gtst]

Do you have way to view your knock sensor info

high count can suggest not enough fuel.