Tag Archives: Cobb

Subaru Knock Monitoring – Cobb Tuning

I read Cobb Tuning’s Facebook postings and saw the following the other day:  http://www.cobbtuning.com/subaru-knock-monitoring-and-dit-knock-logic-changes/

Most people that have turbocharged Subarus and either have a Cobb Accessport or want one always ask how does one monitor for knock.  I’ve elaborated on this in the past (here) but the information in the link comes straight from the source!

Excerpt:

Detonation events are inevitable and will occur from time to time on any modern vehicle running on pump gas.  Your car is built to recognize these events and take the appropriate action to defend against them causing any damage.  The Subaru knock detection system tends to err on the side of caution.  This makes it common to see “false knock.”  False knock occurs when the ECU corrects for a knock event but the noise registered is due to other noises that aren’t necessarily detonation or harmful to the engine.  This often happens accelerating from a stop while letting the clutch out, during gear shifts (more so if grunting while shifting), accelerating at low RPM in a high gear, under cruise on the freeway, and during abrupt throttle changes.

Read the rest at the above hyperlink.  Enjoy!

Firmware updates for ALL Subaru Accessports!

http://www.iwsti.com/forums/cobb-accesstuner/271467-firmware-updates-all-subaru-accessports.html

I like leveraging IWSTI forum posts (because I spend a good bit of time reading and posting there).

Cobb has updated the firmware for all Subaru APs.  The notes are below:

Fast Logging for ALL Subaru Accessports!!

We’ve improved datalogging rates for all Subaru Accessports. This includes V2, V2b, and V3 units and all Subaru Accessport part numbers.

V2 and V2b units will now see improvements in excess of 300% over previous datalogging rates. V3 Accessports will see nearly 250% higher resolution.


OTS Map Updates!!

2008-2014 STI v334 Map Updates

  • Revised Engine Load Compensation tables to address potentially high absolute values in the A/F Learning “C” range.
  • Activated new toggle to induce Per-Gear Timing Compensations for 6th gear.
  • Eliminated factory “Fuel Enrichment Ramping” behavior that caused temporarily lean conditions following shifts while driving aggressively.


2002-2007 WRX v310 Map Updates

  • Massive update for Stage1 and Stage2 mapping. Includes refinements to boost control and overall ignition timing strategy.
  • Added Stage1 and Stage2 support for COBB Electronic Boost Control Solenoid (EBCS).


2009-2014 WRX v331 Map Updates

  • Synchronized mapping across all model years.
  • Implemented Per-Gear Timing compensations.
  • Reshaped Boost Targets table for better control at higher RPM which reduces need for Severe Low Wastegate (SLWG mapping).
  • Removed SLWG maps from map offering
  • Revised odd factory Per-Cylinder Injector Pulsewidth tables
  • Updated Primary OL Fuel tables.
  • Revised ignition timing tables based on power and detonation concerns.
  • Many minor adjustments (changed per-cylinder timing compensations slightly, disabled trims based on rear O2 sensor, revised closed loop fuel target at idle, etc.).


For access to updated features, simply connect your Accessport to Accessport Manager and perform a firmware update!

For any other questions, feel free to email support@cobbtuning.com or submit a support ticket at cobbtuning.com/support

The coolest part?  The increase in datalogging rates — 300% for pre-v3 APs and 250% for v3s!!  What does that mean?  Better (quicker) logging!  That means better quality datalogs!

Cobb AccessPort – How do you use yours?

I’m a member of several large WRX/STI sites/forums and while I lurk on every one but IWSTI, I read a lot between them all (and sometimes subscribe to those that attract my attention).

I’ve noticed a trend with Cobb AP usage.  With version 3 out now, people are using the AP as a gauge (or a set of gauges).  That’s OK, but I don’t think the unit was designed to replace an actual boost gauge and I’m pretty sure the mechanical gauges will always be more accurate.  I guess it’s OK to use the AP in that capacity, but it can be dangerous if you’re depending on it in that capacity.  It’s one thing to use it while knowing that it may not be 100% accurate…it’s another to think or assume it’s the better tool, because it isn’t.

As well, I’m also noticing a trend where people will use the AP as gauges and monitor real-time in lieu of logging events via the datalog feature.  This thread in particular highlights this problem.  That is definitely dangerous and here’s why:  Monitoring gauges real-time isn’t really real-time if you’re not watching them (you’re not going to be able to watch them and drive at the same time…you might think you can, but you can’t).  Now, under each virtual gauge, there are areas that monitor the lowest and highest measurement of that particular gauge.  Let’s say you’re trying to watch the Fine Knock Learn (FKL) gauge while driving.  You eventually look at the AP and see that while you weren’t looking at the gauges, the AP logged an FKL event.  The counter under the gauge shows the value of, for example, 1.35.  The thing is, you don’t know if it counted that once, or many times while you weren’t looking at the gauge.  Also, this also tends to create a false sense of security because you’re thinking, “oh, there was only one event” when there could’ve been 20 while you weren’t looking.  One measurement showing within the peak value field does not mean there’s nothing to worry about.  That one measurement could be happening more than once.  Very rarely do I actually see an FKL event showing within the AP gauge as it occurs (that’s only happened twice).  Now, if you’re datalogging as well as live-monitoring, that’s a different story.  The analogy that I used in a post at IWSTI is that live-monitoring is akin to reading Cliff Notes, while reading datalogs is akin to reading the actual book and not a summarization of the book.  Based on what I’ve been reading in the forums, people are using the AP’s live monitoring as the only method of monitoring.  I saw at least one guy today state that he has 70psi in cylinder #4 but when someone asked him to post logs awhile back, he didn’t have any, yet he stated that he saw knock events…it is assumed that he saw those knock events on his AP.  He never did post the logs but then posted he had a bad cylinder/piston/ringland.

Subaru owners will need to be extra diligent in following their cars’ maintenance schedules, datalogging (especially after filling up the tank with new gas), not beating up on the car when the engine is cold, ensuring the oil has the proper level, ensuring the oil is clean, ensuring the engine isn’t being lugged in a high gear (no flooring the engine in high gear or on inclines)…following those instructions can lessen engine damage, but logging is key, in my opinion.

Lots of Knock!

A few days ago, it got warm enough to where I wanted to go to a car meet.  I took the car (of course) and ran logs on the way out.  I also ran logs today when driving to a doctor’s appointment.  Well…I saw lots of knock…WTF.  The only thing I can think of that’s causing it is bad gas (I filled up on Friday…those logs were partially clear).  Thinking on it now, it could also be the fact that the weather is warmer…warm enough to have heat-soak (which could contribute to knock on the OTS Stage 1 tune).

I got scared enough to where I unmarried the AP…it may stay unmarried until I’m ready for a protune.   While the DAM was still 1.0, the knock was very prevalent (finke knock learn, actually, which pulled timing quite a bit in some instances) .  I’ll see if I can post the logs.

EDIT – The logs are here.

UPDATE – I think this might have been a combination of bad gas and the fact that the engine was loaded and in top gear. No, I wasn’t lugging the engine, nor was I boosting significantly in 6th, but I was in 6th with light load and running the AC, which the 93-octane Stage 1 OTS tune doesn’t like. When I went to the Stage 1 91-octane OTS tune, it stopped. I’m still running the 91-octane Stage 1 tune.

Fix for STI Stumble

So, there’s a thing called the ‘stumble’, where there’s a fueling issue that causes an STI engine to falter or lean-out.  In some cases, it is noticeable, especially when getting tuned.  Some tuners can tune it out while other can’t/won’t.

There are several fixes:  1) using an aftermarket fuel pressure regulator; 2) using an aftermarket fuel rail; 3) extending a fuel line.  The below links describe how to perform #3.  As well, after doing fix #3, it is advised to use Cobb’s Accesstuner (if you don’t have it, you can request it from Cobb at this link) to modify your TGV tables (as they were modified by Cobb to compensate for the stumble)…the first URL below explains how to do it.

http://www.iwsti.com/forums/how-install/254372-fuel-line-extension-stumble-fix-mod.html

http://www.iwsti.com/forums/2-5-liter-litre-factory-motor/250449-parts-needed-installing-longer-fuel-line-stock-fpr-hard-line.html

I do plan to do this as soon as I can.  It shouldn’t take any more than 20 minutes and shouldn’t cost any more than $20 in material.   I plan to do this before I get protuned.

Note that this only affects later model STIs (2008-2014)…it does not affect the WRX or other models.

Mishimoto Cold Air Intake for 2008-2014 STI

subaru-wrx-sti-performance-air-intake-2008-2014-39

http://www.mishimoto.com/subaru-wrx-sti-performance-air-intake-08-14.html

This cold air intake (CAI) is a bit different than that’s currently on the market for the GR/GV STIs.  What’s different?  Your vehicle doesn’t need to be tuned for it to be used on your car, nor does it need to used with a Cobb AP OTS tune.  In most cases, CAIs for Subarus are not plug-n-play.  So when I saw the above URL posted within the IWSTI forums, I immediately had questions, such as ‘how did they do this?’.

Here is an engineering writeup of the product (by Mishimoto engineers).  It is actually pretty thorough.  Another cool fact is that it can still be protuned for further gains.  Mishimoto claims,

The maximum gain achieved was about 25 hp and 24 tq at around 5300 rpm, with a peak gain of 12.7 hp and 2 tq. These results are very good for such an easy part to swap out. Increases on average through the power band measured around 20 hp and 18 tq, which would certainly be noticeable to the driver.

Additional notes regarding the air/fuel ratio of a car with this particular CAI:

The Mishimoto CAI follows the stock AFR as the car builds its boost. Once the engine reaches 4000 rpm the car is under full boost, as seen when the Mishimoto CAI starts to differ from the stock unit. The maximum AFR reached was about 11.7:1, but on average the Mishimoto CAI runs about 11.3:1 when under full boost. The stock AFR maxed out at about 11:1 and averaged about 10.5:1 when under full boost. These numbers were consistent throughout multiple runs, which assured the engineers that this CAI can be used every day without harming the engine.

Looks-wise, I like the Nameless Performance CAI better, even though that particular unit still needs a Cobb AP to be used (it can be used with any map that supports the AEM CAI).  Pricing between the NP and Mishimoto CAIs are also very similar.  The NP CAI is $299 and has an arsenal of color choices of the closeout and MAF housing.  The Mishimoto CAI is $313 and only offers 3 colors of the intake piping.

I’m not sure which offers better gains on OTS tuning, but I don’t think you can go wrong with either solution.

Downpipe and Cobb AP have arrived!

So, my CNT catted downpipe  (from Cygnus Performance) arrived yesterday (Friday).  I did NOT know it was coming and was fortunately home when it arrived.

20140314_235055_HDR

Notice the placement of the cat.  I’m not sure I’m liking it’s position, because there have been complaints that the cat has melted the passenger-side CV boot, spilling CV grease everywhere (and at least a few instances of that grease catching fire from the cat’s heat).  The cat is big enough that it is less than an inch from the CV boot.  This isn’t the only brand that places the cat on the neck of the DP…Invidia does it, as well as a few other brands.  

So, I’ve three options to mitigate the heat of the cat from causing damage:

  1. Fabricate some type of heat shielding (doesn’t necessarily have to be a metal shroud-type of shield).
  2. Heat-wrap from the top of the neck to the bottom (wrapping the cat as well, since the cat is the main cause of the heat damage).
  3. Get a DP that has the cat near the tail.

Yes, heat-wrapping the cat can cause the cat to fail, but I’ve asked on IWSTI if anyone has ever had a cat fail because it was heat-wrapped…I got no answers.  I’d rather not heat-wrap the cat but I might not have a choice if I can’t find or fabricate a shield, because I’d rather melt the cat than melt a CV boot and damage the axle ($600 to replace) or even cause a grease fire.  I could also just sell the DP and use that money to get a better DP…I’d need $300 extra, though.  The CNT is priced at $369, which undercuts the higher-priced DPs with lower mounted cats by a good bit ($100-$250 more).  What I’m more than likely going to do is use the CNT (heat-wrapping the vertical part) and start putting money aside to get a Cobb catted DP when the CNT fails.

I’m also going to probably reinstall the stock mufflers.  Why?  Because, with the CNT DP, the current setup is going to be pretty loud (we’ll see).  My current setup consists of an axleback muffler delete system.  Without some type of muffler, the car will more than likely be loud since aftermarket DPs tend to be higher diameter and less restricting (the stock DP has two cats, I believe, which would probably help in masking sound).  I’ll run the stock mufflers until I can come up with an alternate solution (I very much want Nameless muffler replacements, but they’re around $400, much more than my Nameless axleback deletes).

 20140307_141141_HDR 20140307_141103_HDR 20140308_151930

My Cobb AP v3 also arrived.  I purchased from Amazon.com and found cheaper pricing than at online tuning shops.  They typically sell them at $650, but I got mine for $639 and used the different for faster shipping…note that SKOOT LLC is selling them for $624, which is even cheaper than when I bought mine 2 weeks ago.

The AP is very nice…it should be, for $600+.  It is built well and comes with a good bit of accessories:  a USB cable for connecting to laptops to get map and firmware updates; a OBDII cable, a blue faceplate, a quick start guide, a mount, and two Cobb stickers….oh, and a case.

The unit itself has a screen that’s about the same size as an iPod.  It offers virtual gauges and you can configure it to show between 1 and 6 of them.  It also datalogs, displays any trouble codes, has launch control options, has a configurable shift light, and has Cobb’s off-the-shelf tuned maps for specific mods and fuel configurations.  The unit can be used while driving but isn’t required.

Now the only differences in capability between the v2 and v3 models is that with the v3 you can have more than one gauge up and running.  If you’ve a budget, you can still buy the v2 models…they still log data and can do pretty much everything the v3 can do.  If I really wanted to cut the budget, I could’ve just searched for a used v2, which I’ve seen as low as $350.

I’m still awaiting other parts to arrive, but I’ll begin to work on the heat-wrapping of the CNT this week and post pictures when I’ve finished.

Cold Air Intakes by Nameless Performance

 Nameless Performance Cold Air Intakes for 2008+ WRX/STIs, coming January 2014.

 

 

 

 

After seeing this FB post, I’ve decided to purchase a Cobb AP and this intake (provided it is reasonably priced, ie $200 or so).  I’m actually still on the fence about the AP purchase, but looking at that FB post and the dyno chart posted by Nameless, the gains are really strong (9HP and 34TQ, peak measurements), you can’t really argue with that.  And Nameless even posted a chart awhile back that showed similar gains with just the damned axleback…crazy.  Add the Nameless axleback, the intake, and a safe but good protune, and I’d be close to 300TQ and maybe 260HP.  And I suppose if I get in over my head (I’ve done the modding game before…after awhile, it got tiresome, and that was before my kids arrived), I can always remove the bolt-ons and revert to an OTS (or run stage 1 without mods & with safe protone, which would still give me gains).