Hi,

I am running Cobb Stage2 93 maps, can you please advice me how to tune out the gap in Load in 3-4k RPM? in 4000 - 4500 RPM the load jumps up and goes slowly down by redline. This is 4th gear pull.


Both selenoids are maxxed out already.

 

The load will always go down toward redline. (Not sure if that was part of your question)

Regarding the cells you have highlighted, are you going over your boost target load?

 

He's talking about the boost/load dip.

You need to adjust your WGDC and/or correction tables.

 

Are you running a test pipe or cat?

That dip is actually quite noticeable. That was the first thing I noticed when I flashed stage 2. It pulls hard till about ~3k and then it kind of plateaued until ~4k and then picked back up.

I am running Cobb AMS 93 Stage 2 and this exact thing was happening on mine. I adjusted WGDC Fine/Coarse and got my boost to stop dipping. Of course, like it was stated before, make sure you are not exceeding your boost load target, when you do that you will start getting some correction factored in. Boost load target for Cobb Stage 2 93 from ~3.5k up is 309 (189(boost WOT B)+120(offset)). As you can see you are in the low 200's.

 

I've been fighting with this for a while. Nothing seems to help. I think it has something to do with Mivec or the Airflow tables. Not sure which one. Last time I was tuning my car on the dyno, I was researching the Mivec area. I was pulled from the dyno due to actual customers coming in. So I never finished the research.

 

Peaky customers always impeding research.

I'm fighting this as well, and haven't found enough pavement to resolve yet...plus I'm starting to wonder how hard this must be on the car when it takes 30 pulls to try and smooth it out.

If you suspect Mivec, couldn't you correlate the rpm/load with the MIVEC table to prove it's mivec?

 

I totally changed my MIVEC, via HollywoodX's help, and mine still did it. We didn't just tweak MIVEC we totally refactored it.

 

Slow to close WGA?

 

Dunno, I got my boost evened out with WGDC. I would love to find out whether the load dip is just how it is or if there is something else behind it. Although, my timing load doesn't fluctuate as much as his is doing. My MIVEC changes may have caused mine to smooth out, Golden may be on to something.

I will have to look at my logs from before OTS and see if the MIVEC change caused mine to smooth out. I do recall there being some nasty variations in the 3.5k area on the stock MIVEC.

 

my observations:
a- you need to log timing advance (AFR wouldn't hurt, either)
b- your throttle position seems low at 86. mine is usually at 96 at WOT.
c- despite (b), your spool characteristics seem fine. however, you are at 100% WGDC beyond 2750, whereas I am at 71%. You are on stock boost solenoids? I am on a GM BCS. Logging Active WGDC Correction, as well as Boost Error Correction (if it works for you) would be helpful (as would a longer log).

Attached you will find an image and log(rename to .csv) of a 3rd gear pull I did this morning that illustrates the [b]load/[b] dip you speak of(note, no dip in boost). Because boost remains a well-formed curve, I am confident I will be able to smooth this out with a little bit more WGDC in that area and a degree or two more of timing.

(did I mention I love map tracer? wish the x/y axis were user-definable so you could tracer other tables besides timing/fuel)

 

The AP normally only reads to ~86.47 at WOT. So he is pretty much nailing it. Anything over 80 is considered WOT with the applicable tables.

 

Well I am not hitting my Target Load, so there should not be any correction kicking in.

I run on Milltech TB with HFC, stock boost control - both selenoids are at 100% in these conditions.

How could be Mivec tweaked to help with the dip?

 

I never hit target either. I am not sure on the MIVEC, I am no wizard, I just know what HollywoodX did for me worked great. All of the changes he made were in the intake side.

 

Is it possible you are hitting the ASC off condition and getting the requested torque reduction? I'm not sure what your boost units are.

 

nope, 185kPa = 27psi

to the OP: ditch that stock solenoid setup for a 3port. also, just because you are not hitting your load target in the solenoid map doesn't mean you're not hitting one of the other limits elsewhere. I have no idea what Cobb changes/can change, but in ecuflash we have a "hard" boost limit table that limits load at any given RPM... but its set at 269 from the factory at the RPM you are experiencing the issue so I doubt that is it unless Cobb load reads lower than real load like the TPS apparently does...