Pro tune no longer hitting peak boost

2005 Legacy GT.

 

Mod list:

Perrin EBCS

Perrin top mount

Unknown up pipe

Cobb catted downpipe

Perrin cat back

Act clutch

Vf52 Turbo

Rebuilt engine with acl bearings

Rebuilt 5 speed

Perrin Bpv

DW 265lph fuel pump

Copper ngk plugs

 

Issue prior to rebuild and after car stopped hitting boost targets. All resealed and new gaskets. Turbo is less than 1 year old and no shaft play.

 

I have disconnected wastegate vacuum line and boost seemed to drastically increase (did it to test actuator).

 

I have not smoke tested...however we are not talking a little bit. Tune is 21psi however currently reaching 15.9-16 on accesport boost gauge. It has caused longer spool times than when it was going wrong.

 

Next step is to smoke test to rule out leaks. However....any other possibilities? Go

 

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Since you have an accessport, can you record some data logs and post them here? The default logs fields would be a good start.

I will attempt to get the datalogs done asap.

 

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Also check AF Learning #1A, B, C, D (the fuel trims). If you have a leak it's likely to be reflected in the fuel trims. Don't necessarily need to datalog them, you can just check them via the live view on the AP.

Make sure your map sensor is plugged in, also make sure the vacuum lines for the map sensor are good no rips

So. I data logged a 3rd gear pull. I just have to get to my pc so i can upload it. I will check the map sensor vacuum lines tomorrow.

 

Odd thing that has occurred the past 2 new york state inspections. The pcv system would not become "ready". I had to force readiness with the test connectors. (May be completely unrelated). But i will check everything and upload datalog

 

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What am i looking for under the a/f learning values.

 

Map sensor and all vacuum lines are double checked.

 

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So here is a snippet of the Data log.

Is there a .CSV file that you can upload?

See what your fuel trims are (AF Learning #1A, B, C, D). Preferably they'd be +/- 5% or thereabouts. A pegged A trim (15% for most tunes I've seen) would definitely indicate a leak. If those check out OK-ish, maybe add WGDC and WGDC Max to your parameter list to see if your boost is being capped by WGDC.

csv file sorry.

datalog10.csv

See what your fuel trims are (AF Learning #1A, B, C, D). Preferably they'd be +/- 5% or thereabouts. A pegged A trim (15% for most tunes I've seen) would definitely indicate a leak. If those check out OK-ish, maybe add WGDC and WGDC Max to your parameter list to see if your boost is being capped by WGDC.

I did send the datalog to my tuner as well. But I'm positive it was not an issue with the original tune. It used to drive AMAZING. People still think its quick, but to me it feels lazy. lol

Is your tuner willing to help you? I don't want to interject if your tuner is willing to help because we might give you conflicting advice.

 

A few key things I'll mention though:

1) Hotter weather can do this, especially if there is no positive compensation dialed in for IAT WGDC compensation

2) Even with compensation, you can only do so much. Hotter air doesn't compress as easily, period.

3) If your Max WGDC or TD Int is limiting your WGDC, you may be capping out and it may need to get adjusted.

 

I would suggest in the future you log IAT too and remove Dynamic Adv() and MAF Volts.

 

It's a shame your logging interval is so crappy (300+ms!)

His 1st suggestion is to replace PVC. Car has had issues with "pcv readiness". I am going to order the whole unit+hoses and perform another datalog. I would understand warmer temps ect...but it is 60° or so...and in august i monitored boost at a track event and pulled 18psi on this tune. I have been reading some post on forums regarding bad pcv causing delayed boost ect....if pcv makes no difference i will make adjustments. But any advice is welcome, especially if i can discuss with the tuner. Thanks guys!

 

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Ironically I did a 3rd gear datalog 2.2k-5.7k on the way home from my daughter's dance class (she -does- egg me on actually). Starting IAT was 86F.

 

My WGDC are -much- higher than yours. My main upgrades are similar to yours: Perrin inlet, VF52, IPR TMIC (aka Perrin clone), GFB Respons BOV, GS EBCS, DW740's, DW65c pump, TGV deletes, Invidia catless UP, Cobb catted DP, Nameless resonated mid/Y w/ stock mufflers.

 

My WGDC was mid-70% b/n 2200-2400 rpm, mid-60% 2400-2600 rpm, low-mid-50% b/n 2600-3200 rpm, then 48-50% from 3200 to >5000 rpm. Peak boost during that pull was ~19.25 psi b/n 3300-4000 rpm, tapering to and holding ~18.2-18.7 psi b/n ~4200-5000 rpm.

 

I'd def add WGDC Max and as iNVAR implied, your TD parameters (integral, proportional) to see if your boost is being tune-limited.

 

IIRC my PCV assy become disconnected at the vertically oriented connector on top of the motor, visible by peering down b/n the intake manifold and TMIC on the passenger side. It stunk like raw fuel and I -think- my AF Learning 1A trim was pegged at the tune's max of 15% (might be wrong on that, as the boost/vac hose that connects to the underside of the intake manifold had blown off around the same time. Things cleared up nicely after I re-seated the PCV into that connector. If your PCV is the orig one that came w/ the car, it's probably a good idea to inspect/replace it anyway.

 

As for the AP logging interval, make sure your AP is on a recent firmware version. On both the V2 and V3 AP, newer firmware versions significantly improved the logging interval. I used to see 3 samples/sec, but now see 10-11 while logging 12-13 parameters on the newer firmware.

This is a 2nd gear pull with PCV valve replaced.

datalog5.csv

There was one of the af learning values as like -7-8

Not the boost controller, not the wastegate. I am going to smoke test...if i have to retune it may be time for injectors, tgv deletes and a header.

 

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Let us know the smoke test results. If that checks out, redo a datalog but remember to include IAT, both WGDC -and- WGDC Max and your Turbodynamics parameters. Your most recently posted 2nd gear datalog didn't include WGDC Max or turbodynamics, so we don't know if your boost might be capped by the tune.

 

Also, a 3rd gear pull will probably be better since the engine will be more loaded in that gear and boost should build more readily. For what you're looking to find out, you'd probably only need to do a 2k-5k pull max, although w/ your setup I would think you'd be hitting target boost somewhere around 3k in 3rd, maybe 3.9-4k if the pull is done in 2nd, so even a 2k-4k (or 4.5k) pull should be sufficient.