Not hitting Stage 2 boost targets (boost leak?)

[Bubba Ho-Tep]

Just upgraded my HPFP internals (autotech), Cobb DP, and went to Stage 2. After some logs I noticed I'm not hitting my 18.5psi boost target (stage 2 w/o tip). It may be a boost leak but I wanted to post some logs to see if anyone see's anything else that could be the cause.

If the logs check out ok and I go ahead and order a boost leak tester, where should it be attached. I've heard some people say right at the top of the TIP (right where the intake would connect)- other say right at the turbo compressor. If I do have to order (or make one) I want to make sure I have the right size as the turbo and opposite side of the tip are different sizes. Thanks in advance everyone!

PS All the logs were 4th gear pulls, at sea level, approximately 72 degrees out.

[speed14]

This is with a Stage 2 OTS map?

I suspect you're hitting your load limits, which is the reason you're not seeing 18psi. You can see your throttle plate closing to stay under the requested load.

You can learn how to raise the load limits in ATR to reach desired boost, or have one of the e-tune guys do it for you. I don't think you have a boost leak.

-good luck

[WillyH]

Increase your WGDC 500 rpms before the area where you see your boost not reaching the boost targets. For amount of increase, try calculating a % based on the boost your getting vs target boost.

For example, @ 3000 rpm, lets say you're getting 14 psi, and you're targeting 18 psi, (1- (14/18))*100 = 22%, so increase WGDC by 22% @ 2500 rpms.

To be more conservative, you might want to try 1/2 that so 11% to see if your car is adjusting how it should.

If anyone disagrees with my method, please correct me.

IMPORTANT: You should also be going WOT @ ~ 2500 RPMS till 6500 rpms. Don't adjust your map until you post a proper WOT log or 2. If you adjust your map based on your current logs, there could be issues.

[bigriver]

OP - was your DSC and AC turned off?

[Bubba Ho-Tep]

Originally Posted by speed14 This is with a Stage 2 OTS map? I suspect you're hitting your load limits, which is the reason you're not seeing 18psi. You can see your throttle plate closing to stay under the requested load. You can learn how to raise the load limits in ATR to reach desired boost, or have one of the e-tune guys do it for you. I don't think you have a boost leak. -good luck

Hey, thanks for taking a look and responding. I haven't gone the route of ATR software because I know so little about tuning, I don't want to tinker with something don't understand. That's what I get for being more of an A/V geek and not a gear-head.

I'm going to install a Cobb TIP soon and reflash with the Stage2 (w/ tip) as the Tip I had previously (from another company) wasn't molded properly. The fitment wasn't even close. I'll most definitely have to get an e-tune/protune. Btw, if I WERE to check for a boost leak should I be connecting the tester to the tip or the turbo itself? Also should I pressurize the system to around the same PSI the tune is asking for 18-19psi or more?

Originally Posted by WillyH Increase your WGDC 500 rpms before the area where you see your boost not reaching the boost targets. For amount of increase, try calculating a % based on the boost your getting vs target boost. For example, @ 3000 rpm, lets say you're getting 14 psi, and you're targeting 18 psi, (1- (14/18))*100 = 22%, so increase WGDC by 22% @ 2500 rpms. To be more conservative, you might want to try 1/2 that so 11% to see if your car is adjusting how it should. If anyone disagrees with my method, please correct me. IMPORTANT: You should also be going WOT @ ~ 2500 RPMS till 6500 rpms. Don't adjust your map until you post a proper WOT log or 2. If you adjust your map based on your current logs, there could be issues.

Thank you also, kindly, for taking the time to read the logs and respond. Unfortunately, yes, this was the Cobb OTS map for my car with appropriate mods, but I didn't request the ATR software yet. I have to check to make sure they have it for the Mac. Additionally I'll probably have to have a professional tune it because in all honestly most of what you said was greek to me. If I understand correctly you are talking about using the ATR software to increase the Wastegate Duty Cycle to allow the turbo to produce more boost?

My hats are off to you guys- this stuff is so perplexing to me. I absolutely love cars but apparently am quite a newb when it comes to anything more technical than basic hardware installs.

Originally Posted by bigriver OP - was your DSC and AC turned off?

Yes and yes sir! Thanks!

[WillyH]

This may help and save you some monies.

comprehensive tuning link list

"If I understand correctly you are talking about using the ATR software to increase the Wastegate Duty Cycle to allow the turbo to produce more boost?"

Yes, more boost to hit boost targets.

[bigriver]

I think the Cobb tuning notes say there is a boost target error factor of +/- 1.5 psi with the ots maps.

[SofaKingAwesome]

For starters, you should start logging @ 2800-3000 RPMs.
You're cheating yourself out of 1k RPMs for the turbo to spool.
Take some logs starting there and see where you're at. You may just have to make small tweaks to the WGDC tables or the TRL by gear tables.

[speed14]

Just putting this out there, but if you're already hitting your load targets, there's no amount of WGDC you can add that will increase your boost.

The only thing that will happen if you continue to raise WGDC on this map is when you go WOT, you will see a spike above the requested load on spool-up since the ECU uses the WGDC tables and ramp limits as a starting point, then LEC will kick in as you exceed your load targets and cut WGDC to bring you back to meet your requested load targets.

If you wan't some proof, i looked at the 4th gear load targets for a stage 2 map and your logs are dead on with the requested loads.

In summary, all this means is your car does not need to hit 18psi to meet the load targets of a stage 2 OTS map. Time to get tuning!

[Bubba Ho-Tep]

Originally Posted by WillyH This may help and save you some monies. comprehensive tuning link list

Lots and lots of reading to be done- thank you.

Originally Posted by bigriver I think the Cobb tuning notes say there is a boost target error factor of +/- 1.5 psi with the ots maps.

What does that mean exactly? That the boost targets simply may not be reached and require additional tuning (professional, or ATR) to correct it?

Btw, I requested my link for ATR and got an email only a few hours later. I went to install it but quickly realized it's ONLY for Windows. Their AP Manager software is PC or Mac compatible but not the ATR unfortunately.

Originally Posted by SofaKingAwesome For starters, you should start logging @ 2800-3000 RPMs. You're cheating yourself out of 1k RPMs for the turbo to spool. Take some logs starting there and see where you're at. You may just have to make small tweaks to the WGDC tables or the TRL by gear tables.

I'll give that a shot- I just try to stay away from gunning it at lower RPMS, though, I can see from my logs I was pulling from over 4k each time.

Originally Posted by speed14 Just putting this out there, but if you're already hitting your load targets, there's no amount of WGDC you can add that will increase your boost. The only thing that will happen if you continue to raise WGDC on this map is when you go WOT, you will see a spike above the requested load on spool-up since the ECU uses the WGDC tables and ramp limits as a starting point, then LEC will kick in as you exceed your load targets and cut WGDC to bring you back to meet your requested load targets. If you wan't some proof, i looked at the 4th gear load targets for a stage 2 map and your logs are dead on with the requested loads. In summary, all this means is your car does not need to hit 18psi to meet the load targets of a stage 2 OTS map. Time to get tuning!

So you are pretty sure it's not a leak- if it were I wouldn't be hitting my load targets? Thank you again!

[WillyH]

Originally Posted by speed14 Just putting this out there, but if you're already hitting your load targets, there's no amount of WGDC you can add that will increase your boost. The only thing that will happen if you continue to raise WGDC on this map is when you go WOT, you will see a spike above the requested load on spool-up since the ECU uses the WGDC tables and ramp limits as a starting point, then LEC will kick in as you exceed your load targets and cut WGDC to bring you back to meet your requested load targets. If you wan't some proof, i looked at the 4th gear load targets for a stage 2 map and your logs are dead on with the requested loads. In summary, all this means is your car does not need to hit 18psi to meet the load targets of a stage 2 OTS map. Time to get tuning!

He will most likely hit the boost targets if he starts his WOT run at 2500 rpms. His turbo didnt have enough time to spool up fully. With the new logs, if boost still isnt meetings targets, apply the method above by increasing WGDC.

For the record, on stage 1, I was able to go up to 21 psi. If he is boost tuning, and the load tables are zeroed out, i dont think load has anything to do with boost. Correct me if im wrong.

[dantes5823]

Well if he cant get ATR loaded then he cant do shit to his map. And wont be able to get e-tuned either. First course of business would be to get ATR on some kind of computer and then you can start adjusting. Pretty sure he isnt leaking, wouldnt his wgdc start freaking out and wouldnt his boost go up and down? It def looks like he's hitting his load limit. Which is pretty simple to work around. I would do that first before working wgdc's. He'll end up raising them then doing the load then over shoot his target.

[speed14]

Originally Posted by WillyH For the record, on stage 1, I was able to go up to 21 psi. If he is boost tuning, and the load tables are zeroed out, i dont think load has anything to do with boost. Correct me if im wrong.

Not saying you're wrong, just providing my tuning experience..

Even having my load dynamics tables zeroed out, my car was still limited by the TRLxgear tables, as i believe is the same thing happening to the OP. really think it depends on the ECU as some cars do not have this problem.

Only after i raised the TRLxgear values to unachievable levels (ie 2.5 or higher) i was able to reach my boost targets and make adjustments by simply raising/loweing WGDC.

[fortressofcomfort]

Make sure all the Throttle Requested Load - x gear tables (look in Throttle area of ATR)are set to something like 2.5 from 2500rpms and up

Also make sure your Load Error Comp table under Wastegate Dynamics is all zeros.

Like Dantes5823 said, if you don't have ATR then you are SOL now and down the road when you WILL want to get an etune. The OTS maps are merely starting points for REALLY getting your car running good (the difference, for me, from going from a stage 1 Cobb map to my own eTune with help from lots of great guys see sig was 12whp and 67lb/ft at the wheels; sounds funny but its easy to make torque increases on these cars and much harder to make peak hp increases because K04). Try running nearly 106mph in the 1/4 mile with an intake and OTS Stage 1 tune lol. Remember, Cobb has to take into account the worst running car possible when they release a map, otherwise lawsuit or at least dissatisfied customers and loss of sales.

I just realized in my sig that I've had help from SEVERAL different tuning teams. This is great. Not only do I benefit from the collective knowledge and argument between teams, but they can all learn something, maybe sometimes a little thing, because they are all tuning the same exact car. Win/Win.

[Bubba Ho-Tep]

I just wanted to take the time to thank you all for the input. I really appreciate it. I've decided to schedule a pro tune at at local Cobb certified pro-tune shop. I'm sure the legendary e-tuners are amazing but I'd rather do the pulls on a dyno. Doing the few hwy pulls I've done so far ranked really high on the pucker factor with the chance of an officer hiding around every corner.

I'll document my experience; fyi I'm using RT Tuning in Lansdale, PA. Probably purchase and have the new Cobb cat-back installed the same day.

[SofaKingAwesome]

Originally Posted by Bubba Ho-Tep I just wanted to take the time to thank you all for the input. I really appreciate it. I've decided to schedule a pro tune at at local Cobb certified pro-tune shop. I'm sure the legendary e-tuners are amazing but I'd rather do the pulls on a dyno. Doing the few hwy pulls I've done so far ranked really high on the pucker factor with the chance of an officer hiding around every corner. I'll document my experience; fyi I'm using RT Tuning in Lansdale, PA. Probably purchase and have the new Cobb cat-back installed the same day.

Damn that's right in my old hood.

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