N55 Turbo Side Intake Progress

[houtan]

Looking better. Your boost is tapering down though and your wgdc is at 100% basically.

If you were at 26psi with the jb4 at 100% wgdc, I would say your car was over achieving! That is a lot of boost out of a ps2. In the log above, I would expect something similar but it’s at 19.

Unfortunately, it’s hard to say what it is. To me it looks like a boost leak but you have checked that thoroughly. Your boost solenoid is new as well right?

I don’t know how the aic p differs from the aic-6, but I use the split second r4 software to log the aic. I ran the USB cable from the white box under the hood into my glove box which I don’t think a lot of people do. Either way, with your fuel set up, you should have zero fuel pressure issues. You can push much more fuel than me and my rail pressure is rock solid on E60 and more hp. In my opinion it would be worth being able to log the controller so your tuner can make adjustments if needed. But again I don’t know the version you’re running very well so maybe that isn’t required.

 

[Alturiak]

Yeah I've gone through absolutely everything with a fine tooth comb, and could not find a defined smoking gun for the boost leak back when I was hunting for it. It for sure has some type of leak either on the turbo or near the turbo, but I couldn't find what or where it was actually coming from. It wasn't the turbo outlet, which to my understanding only leaves the inlet, or possibly the DV connection, right? Or is there somewhere else that a worn turbo would leak from? I thought seals at first but was told that's only if oil or coolant leak is present, which it is not... But also, if there is a seal or gasketed connection it could leak from I'd love to know because it did sit for almost a year baking in the Socal summer sun while the motor was getting built so it's totally plausible sitting like that unprotected contributed to leaking further.

I found my old logs, here's the peak 27psi run I would get with the turbo. Looking at the WGDC I wouldn't be surprised if I was just beating the hell out of the turbo and wore it out within a couple years of owning it

		

			

				
				
				
				
				
				
				

				

				

				

				
				
				
					
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5/17//1
JB4 Android A259
E Series - N55
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17
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...0BE801938
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My understanding from Justin was that he is able to tune the AIC2 such that it can dynamically adjust injector flow based on E content and basically make a true "flex fuel" tune so that I wouldn't have to have separate tunes for different E content and stuff. That and the P version will automatically adjust for elevation changes. But I've never tried actually logging the AIC during a run. I'll a friend to come with to do that haha. But my understanding is that Justin adjusts the AIC by what he's seeing in the STFTs and more recently demand on the hpfp. For example on my pump gas tune with PI he wanted to see just a touch negative STFTs (around -5%, maybe less) so that PI was flowing to keep my valves clean
But to your point, he's been making tune adjustments as we go on the AIC as well. We are currently on the 11th revision on it

 

[wheela]

With that wgdc% issue, I recall you verified your wastegate is fully closing at the right vacuum level, and you even biased it to fully close a little early. But did you ever measure how much vacuum you have available from the car's vacuum pump when it's running?

Even if the wastegate fully closes at the right vacuum level, more vacuum than that is needed to hold it closed in use, as the exhaust back pressure upsteam of the turbine will try to push the wastegate flap open (auto-wastegating). At high loads, you need to have enough vacuum available to overcome both the actuator spring AND the higher exhaust pressure force that's trying to push open the wastegate. So if your available vacuum isn't deep enough, your wastegate flap will auto-wastegate sooner, limiting the amount of boost you can hit. Since you've done so much searching for a boost leak and come up with nothing, I suspect this is your issue.

 

[houtan]

Man you were working that thing! Hard to say if a worn out turbo is your current issue but she has definitely hit some high boost. I am no expert, but can’t the DV leak as well? I feel like I have read that somewhere.

So your AIC is more capable then mine and it sounds like Justin has the data he needs to adjust it.

@wheela , nice suggestion!

 

[Alturiak]

With that wgdc% issue, I recall you verified your wastegate is fully closing at the right vacuum level, and you even biased it to fully close a little early. But did you ever measure how much vacuum you have available from the car's vacuum pump when it's running?

Even if the wastegate fully closes at the right vacuum level, more vacuum than that is needed to hold it closed in use, as the exhaust back pressure upsteam of the turbine will try to push the wastegate flap open (auto-wastegating). At high loads, you need to have enough vacuum available to overcome both the actuator spring AND the higher exhaust pressure force that's trying to push open the wastegate. So if your available vacuum isn't deep enough, your wastegate flap will auto-wastegate sooner, limiting the amount of boost you can hit. Since you've done so much searching for a boost leak and come up with nothing, I suspect this is your issue.

That's a great suggestion, if at the very least to verify it's working properly. I've never touched my vacuum pump setup and while it's never been an issue it's entirely possible sitting for a year may have weakened it. How would I go about testing it? What tools and stuff would I need?

Man you were working that thing! Hard to say if a worn out turbo is your current issue but she has definitely hit some high boost. I am no expert, but can’t the DV leak as well? I feel like I have read that somewhere.

So your AIC is more capable then mine and it sounds like Justin has the data he needs to adjust it.

@wheela , nice suggestion!

She's definitely been pushed in the past! After that log I turned it down slightly so that peak was 26psi even though it was set to 25psi tapering to ~22psi at redline, but the WGDC was pretty pegged at max the whole time too lol. I'm sure the DV isn't impervious to leaks, but I did replace it with the TurboSmart BOV option when I did the upgraded wastegate actuator, to upgrade over the GFB DV+ that was on there previously.

And yeah if the AIC2 can truly be tuned so that flex fuel maps (~E15-E85) are a possibility I'll be incredibly happy with it! Are you running a PI manifold or the PI spacer with stock manifold?

 

[wheela]

That's a great suggestion, if at the very least to verify it's working properly. I've never touched my vacuum pump setup and while it's never been an issue it's entirely possible sitting for a year may have weakened it. How would I go about testing it? What tools and stuff would I need?

To measure how much vacuum you have while running, I'd try connecting a Mighty Vac to the line from your valve cover that goes to your boost solenoid, then turn your car on and see how much vacuum it reads. That should be how much vacuum the boost solenoid has available to work with. Not 100% on the requirement, but per the n55 technical document, it looks like there should be at least 0.8 bar of vacuum available.

You could also use the Mighty Vac to check for vacuum leaks. With the car off, connect to the line from your boost solenoid to the wastegate, and pump up the vacuum to make sure your wastegate and the line going to your wastegate will hold vacuum. Then do the same thing with the line from the valve cover that goes to your exhaust flap, as a leak in that line could also reduce the vacuum available when the car is running.

If all this checks out, and you know you have a good boost solenoid, then you can probably rule out vacuum as the problem.

 

[Alturiak]

To measure how much vacuum you have while running, I'd try connecting a Mighty Vac to the line from your valve cover that goes to your boost solenoid, then turn your car on and see how much vacuum it reads. That should be how much vacuum the boost solenoid has available to work with. Not 100% on the requirement, but per the n55 technical document, it looks like there should be at least 0.8 bar of vacuum available.

You could also use the Mighty Vac to check for vacuum leaks. With the car off, connect to the line from your boost solenoid to the wastegate, and pump up the vacuum to make sure your wastegate and the line going to your wastegate will hold vacuum. Then do the same thing with the line from the valve cover that goes to your exhaust flap, as a leak in that line could also reduce the vacuum available when the car is running.

If all this checks out, and you know you have a good boost solenoid, then you can probably rule out vacuum as the problem.

That is awesome and sounds super simple! I've always wondered if my exhaust flapper was leaky at all since it was disconnected when the Dinan exhaust went on. I have to travel for work for the next couple weeks but will be testing this when I am back. Thanks for the suggestion @wheela !

 

[wheela]

That is awesome and sounds super simple! I've always wondered if my exhaust flapper was leaky at all since it was disconnected when the Dinan exhaust went on. I have to travel for work for the next couple weeks but will be testing this when I am back. Thanks for the suggestion @wheela !

Don't thank me yet, haha! Hopefully this will turn something up. If they had to disconnect the flap for your exhaust, it seems very plausible they forgot to plug the line, or it became unplugged... Hopefully it's the smoking gun, as that should be a simple fix.

 

[dinocrest]

Looks sweet man!, Got any sound clips?

 

[wheela]

Any updates on this? Did you get A chance to look into leaks in your wastegate vacuum system?

 

[Alturiak]

Sorry I've left this thread unattended for while. I've been swamped between traveling for work weeks at a time, and having more pressing car issues pop up. About a month ago after I got back from a trip I hit a pot hole in Big Bear that was bad enough to destroy 2 of my wheels, and when I took them off to inspect I saw my back tires were in need of immediate replacement as well. It's been a very expensive month so far... but I got that taken care of and the car has been throwing 2BC0 code lean fuel mixture at partial throttle or idle. I don't know how hitting a pot hole can do that but here I am. My #1 suspect right now is another vacuum or boost leak. When I logged the other day it wasn't going above 18psi (should be about 23) at 95% WGDC. I have an appointment to get the car smoke tested on Monday so I'm praying an obvious and easy/cheap fix presents itself. In the meantime to address that code I've replaced the hpfp, spark plugs, and both O2 sensors and exhaust gaskets. While under the car I found my intercooler couplers had come loose and needed to be tightened back up but I forgot to check the connection at the TIC while I was under there. Fingers crossed it's not leaking from there bc I hate having to get under the car (apartment life lol)

But this weekend I'm able to test the Mighty Vac theory out and will update with results. I assume whatever results I get will be a bit skewed since there is a known leak somewhere, but it would be nice to rule out that the exhaust flap line isn't a contributing source to the leaks, and that the vacuum pump is also correctly doing it's job.

For sound clips, I unfortunately don't have any, but will work on getting a good one to share here

 

[Stokes]

@Alturiak - Any results from the smoke test?

As for the PS2, I've seen it boost up really nice below 5500 rpm and hit 26 psi with little effort. But if you want a increasing boost curve so that your torque peek is further out in RPM, you'll find that the turbo has a hard time keeping up and needs a lot of WGDC. Pure says to keep it below 80-85% and even sells an upgraded HD actuator to help.

Back to the leak test question... I'm asking as I've done a leak test myself and found nothing, even replaced the boost solenoid. Boost is taking more and more WGDC to keep up these last few months (no senior jokes). Gonna test the vacuum source as @wheela suggested.

Sample home grown PID tune. Super easy when you max the turbo out. The hard control is doing a 16 psi track tune.

E30 mix, E-N55-PWG, Stock LPFP, Stock HPFP, Stock Coils, PS2
https://www.spoolstreet.com/graphs/...?series=2,8,9,10,14,22&zoom=-1,103&isolated=9

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[Stokes]

Ends up a couple small turns of the clamps on the got side piping made a huge difference. Didn't show up under pressure testing since I didn't use smoke and it leaks out the valve cover. But I'm back to big boosties again!

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[wheela]

Wow, that's a nice looking log! Your stft looks really good, what did it look like before you fixed the leaks? Would it get pretty negative in a pull?

 

[Stokes]

Stft were good before the leak. But the leak was only when boost was past 22 psi. So not much of a leak, but enough for maxing out a PS2.

The ps2 is running way outside it's efficient range in that 2nd log. Fuel scalar has been adjusted decent enough to accommodate different fuel demands. My fuel pump is the early e-series pump (aka n54 style), so with some tuning it can go 99% duty cycle and keep up with e30. The setup runs best at around 22psi.

 

[Stokes]

@Alturiak any updates on your low boost issue? Also, how easy is it to put the factory intake back on and do a back to back dyno of the two? I'm super curious if you gain flow as well as it looking better.

One last question, did you have to have the MAF table revised for the new intake design? For some reason I recall reading that changing diameter or was it length, it was a good idea to recalibrate the table. I dunno, maybe I'm just thinking it and didn't read it.

 

[wheela]

@Alturiak any updates on your low boost issue? Also, how easy is it to put the factory intake back on and do a back to back dyno of the two? I'm super curious if you gain flow as well as it looking better.

One last question, did you have to have the MAF table revised for the new intake design? For some reason I recall reading that changing diameter or was it length, it was a good idea to recalibrate the table. I dunno, maybe I'm just thinking it and didn't read it.

I'd think changing the diameter, or cross sectional shape would definately throw things off, as the MAF is just skimming a sample from the edge of the air flowing through the pipe.

 

[houtan]

@Alturiak , quick question, did you leave the stock pcv heater connector unplugged or did you leave it plugged into the stock hose and hide it somewhere in the area?

 

[Alturiak]

@Stokes Got the smoke results mid week last week that revealed a huge leak coming from the silicone coupler on the intercooler outlet (cold side). After I pulled it I found a nice big cut in it. It looks like when it had popped off the intercooler it popped itself right into the drive belt/pulley and was cut that way. I don't why VRSF acts like their coupler is some big trade secret because they wouldn't tell me the intercooler outlet size and I couldn't for the life of me find someone that had documented it on any forums. They said it was custom so I measured everything and it's just a regular 3" 90 degree 3-ply coupler they're charging $40+ for... so of course I ordered the $16 one off Amazon that's 4-ply and arrived the next day. The one I received ended up being about 1/2" short on each leg but that was no issue. New Amazon coupler vs old VRSF "custom" coupler side by side:

I had also pre-emptively bought a new MAF sensor before the smoke test, so I threw that on as well with the new coupler and then proceeded to do the Mighty Vac testing. Attaching the gun to the exhaust T-line and pumping to about 10inHg, it held pretty solid and the decay rate was super slow, so I can cross that being a source of leakage off the list. The line from the turbo wastegate to the boost solenoid is also brand new silicone tubing so that's not leaking either. From there I attached the gun to the exhaust flap line coming from the valve cover as @wheela suggested and fired the car up. A pressure of 0.8bar translates to roughly 23.5inhg, and (assuming the gauge on the gun is accurate) the gauge read about 28inHg:

Seems like my vacuum pump is working nice and strong so I'm thinking "dope, let's check the lean code condition" so I turn the car off to remove the gun and reattach the exhaust flap line and turn the car back on. Long story short the lean condition code is still occurring I tried to log on my way to work this morning and was having issues. I'm thinking the new MAF sensor may behave differently from my old one so I may try re-installing that and see if I can log. It would be interesting (and a little annoying) if tuning for this hot side intake is also entirely dependent on the particular MAF sensor getting used. Anyways, I'll be back at the shop to smoke test the car again and will update with the results after that.

@wheela Thanks for the Mighty Vac testing suggestion! I feel relieved to some degree knowing the vacuum pump and exhaust flap line are not contributing issues to my WGDC issue.

@Stokes I'm glad your issue was a simple hose clamping resolution! Your log looks awesome and I bet your car rips!

 

[Alturiak]

@Alturiak , quick question, did you leave the stock pcv heater connector unplugged or did you leave it plugged into the stock hose and hide it somewhere in the area?

I believe that connector is still attached. I've just tucked it into the AC lines near the front passenger side of the engine bay. How come?