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Intermittent Performance

34R, -9s, e85, haltech etc etc. Approx 350rwkw at 24 or so psi. 

Have recently fixed 2 boost leaks (front turbo to TT pipe and IAT sensor on back of plazmaman cooler) but am finding that even after this the "punch" is intermittent, sometimes it's there/good, sometimes it's lacking that extra kick at WOT. 

Using onboard haltech map sensor so it stops telling me anything useful after 21psi. No faults being thrown, car has wideband and oil pressure kit also. 

I thought it might be intake air temps (pods with an enclosure), as it's been warmer here, but I've had the car feel great and not so great on 27 deg intake temps in the same driving session. 

Car is going in soon for cams and valve springs, but if there's anything else I can check, I'm all ears. I've boost leak tested the entire intake tract up to 40psi using a leak down tester. 

The difference feels like when I went from airbox and 21psi to pods, better cooler, and 24psi, which was about a 20kw/100Nm gain. 

What power are stock GTR bov's good for? Any point in me disconnecting the Mac solenoid for a test? 

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Sounds like it needs a single turbo, twin gates and twin scroll.

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Sounds like you need to go back to Barstow...

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BOV's are fine where you are unless they're faulty.

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Any easy way to test them? Boost leak test doesn't help as any leakage stays in the intake so total pressure remains the same.

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Wait, so you've only got a 21psi map sensor but run 24psi, how does that even work?

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What condition is your electrical system e.g. Alternator output as RB's can suffer voltage drop at mid to high rpm's

type of plugs can make a difference some are better than others if it is a voltage drop.

Check out ADVANCE alternators 150amp as a solution on www.rhdjapan.com they are about $950.00 to $980.00 plus freight.

where does your cold air induction feed from e.g. bonnet, front bar, behind headlight, or intake catch above radiator?

Heat shield between pod filters and engine can help create a cool zone for air pick up.

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Must be the curvature of the earth

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Get a 4 bar MAP sensor for a start.

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Was holding off as the upcoming cam install meant I'd likely need less boost for my goal (500rwhp or so).

Can bovs be intermittent​? Am i just clutching at straws there?

Disconnecting boost control solenoid not gonna tell me much is it, other than actuators are fine to standard pressure (1 bar I think)

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Why did you push more pressure then the MAP sensor can support? WTF is going on there? 

 

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When we did the pods/cooler it was happier to make more boost so was tuned a few pound beyond the onboard map limit.

Similar to what race pace used to do when tuning beyond max flow of the standard AFMs.

Done on the dyno of course.

Anyway can get a sensor, not a big deal if seeing max boost is the absolute first step.



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Could be, then again I was told the same thing - as well as I'm just used to the power - when I thought it wasn't right before and then found two boost leaks.

Need to get it in the dyno me thinks :)

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Similar to what race pace used to do when tuning beyond max flow of the standard AFMs.



So isn't this based on an extrapolation of the tune at the max flow of the AFMs assuming that components are the same and behave the same (linearly)?

If you have had boost leaks and turned on Antilag for a while then things aren't the same / behaving the same?

Is a higher PSI MAP sensor equivalent to using Nismo AFMs (in this regard)?

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Yep, It was tuned on the dyno at 24psi, on his gauge and using my onboard wideband as a cross reference.

 

The anti lag is just a couple of tick boxes and were not turned on when it was tuned, it's also off now so it's not a factor.

 

Wouldn't matter even if it was on as the launch control has nothing to do with what we're discussing here (wot performance) and the rally anti lag only fires between shifts after you lift off the throttle.

 

What I'm talking about is how much power it's making/how hard you get pushed back into your seat, during full throttle stints.

 

That doesn't feel consistent currently, but i cant figure out what the variables are.

 

I thought it might have been purely IAT, as i have pods (shielded yes with cold feed from headlight and inner guard, but still not as well shielded as stock airbox) but the other night out and about for a big Chrysler show locally it was hit and miss with similar air temps.

 

 

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Tried pulling the boost back to a level where the ECU knows WTF is going on? See if it's "inconsistent" then.

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Or heat soak.

Or maybe it's time to crack the barometer out.

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Posted (edited)

16 hours ago, ActionDan said:

Approx 350rwkw at 24 or so psi. 

Have recently fixed 2 boost leaks.

Using onboard haltech map sensor so it stops telling me anything useful after 21psi. 

11 hours ago, ActionDan said:

Disconnecting boost control solenoid not gonna tell me much is it, other than actuators are fine to standard pressure (1 bar I think)

OK.  I've taken a deep breath before saying anything :)

Questions:

1) Is the Haltech controlling boost, or do you have a separate electronic boost control driving the solenoid which CAN see past 21psi?

2) Did you tuner at all oppose this idea of tuning past the MAP sensor's visibility?

3) Did you get the tune looked at after fixing the boost leaks?

 

Edited by Lithium

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lol, deep breathes :D

 

1) Yes. 
2) He said it's best to have the 3 bar sensor but that we can tune past it and see how it goes, I guess this is part of the answer. 
3) No, but I'm certain the car would have only had the IAT sensor leak (small), if at all, as the response and power both on and off the dyno after the tune was solid. I only started checking for leaks as I felt the difference in the car. The big leak was the gasket between front turbo and TT pipe connection. 

 

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