Phone: 520-882-2821

New Website and New Name coming in 2017!

We’re excited to announce that iA-Performance will have a new name and completely redesigned website in 2017! We can’t release the new name yet, but guarantee the same great service you’ve come to know will continue into the future. The owner, and master tuner, Stephen Clark, will also remain unchanged. We’re not selling, nor moving, or the like. Just a new name to carry us into the future.

As for the new site, it will be a ground-up-overhaul site. Some of the many new features to expect are:

  • Visitors can search by Make/Model/Year
  • User friendly shopping cart & checkout process
  • and so much more!

Stay tuned for announcements and updates over the next few weeks.

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Subaru Knock – Explained

COBB Tuning has released an excellent article regarding engine knock detection. This should be a mandatory read for all turbo charged Subaru customers, stock or modified. Feel free to send us any questions you may have as well.

BY KYLE ON 04/30/2015


Subaru Knock Monitoring

Knock! Knock!  Who’s there?  It could be nothing at all, but, it may be cause for concern.  Knowing the difference can give you peace of mind, or, could be an early indicator of a mechanical issue ticking away on your Subaru.  Datalogging and monitoring with the Accessport can provide useful data on these knock events.  Couple that with some basic knowledge and you’re on your way to quickly and easily diagnosing any knock events at any given time.

First, let’s talk about what exactly “knock” is and how it’s detected by your car’s ECU.  Sometimes knock is also called detonation.  Detonation is characterized by the air/fuel mixture spontaneously igniting during the compression stroke.  The force of this early, unintended explosion is counter to the direction of the piston and results in a sharp increase in cylinder pressure.  The increased pressure can exceed the design limits and potentially cause damage.  These events typically result in an audible noise that can sound like a “ping” or “knock.”  The ECU picks up on this noise with a microphone hard mounted to the engine block and listens for specific frequencies that indicate a knock event.  Any number of conditions or factors can induce detonation.  The sources are varied but are generally due to increased cylinder pressure, high temperatures, or reductions in effective octane level.

Worried?  Don’t be!  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.

Relevant Monitors

There are times when these knock events are bad news.  Knowing which parameters to monitor with the Accessport can help determine if that’s the case.  Generally, Dynamic Advance Multiplier (DAM), Feedback Knock Correction, and Fine Knock Learning are relevant when monitoring knock.

  • DAM represents a global adjustment to ignition timing.  If this value is anything less than ideal, it’s a quick indicator something isn’t right (unless immediately following an ECU reset/reflash).  On an 02-05 WRX the values will range from 1 to 16, 16 being ideal.  On all other Subarus, the value is expressed as a decimal from 0 to 1, the ideal value being 1.
  • Feedback Knock Correction is a real-time timing correction the ECU makes based on a perceived noise.  The ECU immediately pulls timing (the amount of the Feedback Knock Correction value) and adds timing back (value rises to 0) assuming no further noise is detected.
  • Fine Knock Learning represents minor learned corrections based on historical Feedback Knock.  If the ECU routinely registers knock in a certain RPM and load range, it will apply timing adjustments which can be seen with this parameter.

In general, we consider Feedback Knock Correction ~-2.5 degrees or less to be “normal” and not of major concern.  If DAM is below the ideal value and there are corrections beyond -2.5, this is good reason for further inspection.  If these corrections occur during full boost and wide open throttle it is especially concerning.

Poor quality fuel is a common cause for knock.  If this is the case, and you’re running an OTS (off the shelf) map, try switching down to a map designed for lower octane fuel.  Switching to an “LWG” version OTS map may also help resist knock by lowering boost pressure.  Use fuel from top tier retailers in your area to ensure your effective octane is as high as its rating.

Common mechanical causes of knock worthy of inspection are worn MAF or front O2 sensors, boost/intake tract leaks, and excessive blow-by.  Definitely be sure to also read the map notes for your vehicle to confirm you have the proper hardware modifications for the map you are running.  These can be found on the website by configuring your vehicle and clicking the maps section.  Then, select your map and click the “notes available” link.  Also, see that you are within the boost range outlined in the map notes.  If overboosting is occurring,  knock may be more prevalent.

DIT DAM Strategy Changes

The newer DIT car’s (direct injection turbo – 2015+ WRX and 2014+ FXT) strategy is a bit more reactive.  This is intentional and is expected since “premium” fuel is not required on the DIT vehicles.  The strategy has changed and is comparable to what may have been seen as Fine Knock Learning in the earlier non-DIT cars may now result in a drop in DAM in the DIT cars. It shouldn’t be surprising to see a drop in DAM on the DIT vehicles (as it is on early cars where DAM being less than ideal is an indicator there is an issue) especially running lower octane fuels.  How long the DAM takes to return to 1 is not indicative of how serious the knock event was and does not mean the car is still knocking.  In order to advance the DAM on DIT vehicles, you have to drive in specific load/RPM ranges without knock.  Determining whether there is a a potential issue on a DIT vehicle require considering how low the DAM has dropped and what other knock responses ( Knock Feedback Correction and Fine Knock Learning) look like overall.

Hopefully this post can help ease some concerns when you see those values under the knock parameters.  If you think your vehicle might be having some negative issue mentioned above, feel free to contact us and we can review datalogs, help troubleshoot, and answer any questions you might have.  Also check out our knowledge base for additional technical information on all things COBB.  If you’re interested in learning more about Subaru Knock Monitoring, check out this FAQ.

Subaru knock detection is like using a large net to catch fish. You’ll definitely catch what you want to catch (actual knock) but you will also catch what you don’t want (false knock). If you used a small net, you would get less false knock but might actually miss actual knock. It’s a compromise.  Be sure to look at the entire picture when trying to determine whether there is an issue.

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Different faces of iA-Performance

During our current face lift, I found it fun to look over the website templates of the past and wanted to share them. The biggest difference for us was the jump from the Blue Template to the Red since it was 400 pixels wider. This allowed for better product spacing as well as a better overall layout. Sadly, I could not find an image of our first ever website back in 2004 :( Thank you to all of those that have supported us over the years!!!

2006-2010                                2010-2012                               2012- ?

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Subaru Forester Limo

This has to be one of the rarest Subarus on the streets today! We ran across this Forester XT Limo on Ebay a little while ago and could not believe our eyes! Hard to believe, but the photos speak for themselves. Sadly, all we have are the photos to share, no power and handling (LOL) stats at this time. Hope you enjoy these crazy photos as much as we have.

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Resurrection of the Mighty s2000!

Here lies a story with a twist. Or should I say, twisted metal… Roughly 1 year ago the smashed Garage Queen entered the iA-Performance stables (shop car).  Over the course of this year it went through an extensive repair process, to say the least. The end result is a car that delivers an unforgettable driving experience plus it turns quite a few heads in the process.

Below are a few photos from the beginning up through the rebirth. Looking back over the photos I nearly forgot how many hours went into repairing this beauty. The body work was performed at Vanderpools Auto Refinishing, Tucson, AZ. As always, their work was flawless and this project was no exception. Although the damage looked quite intense it turned out to not be too bad. The first 10″ of the right side frame rail was bent upwards which was corrected after a short visit on the frame machine. In addition, a 2005/6 s2000 front clip was purchased for replacement fame rail segments (first 10-12″) plus sheet metal, fenders, and headlights.  The project really started to take shape once the new clip items were installed. From there the body work was hung and checked for gaps, they are perfect I must ad. After a complete wax job the car was finally ready to hit the streets for the first time.

First impressions… Despite the car’s size, I quickly realized what fellow s2000 owners relish, true roadster performance.  Not only did it have decent acceleration, but the steering response was also very predictable at both high and low speed corning situations.  Overall, I’m very happy with how the project turned out, plus the wife likes it too :)

Note: As shocking as it may sound, the s2000 was restored back to stock without the implementation of any performance parts, although they were a tough temptation at times.

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Wicked Wide WRX

widebody rear quarter

iA-Performance was fortunate enough to take this 2004 WRX to a whole new level. Not just a new level for our shop, or Tucson, or Arizona, but for most of the Subaru community nation wide!  Come on, when is the last time you saw a wide body WRX with a customized drivetrain/motor? Probably not very often…

The Back Story: we were lucky enough to have the owner walk through our door in late 2005.  At that time the car had a stock drive train / motor, yet it sported this killer wide stance.   Sadly, he had been give the ‘run around’ by a shop in Phoenix, since out of business, for  a JDM ver7 STi motor. Money had exchanged hands, yet 6 months later there was no motor to be seen. Luckily a full refund was tendered by the ’shady shop’ (cough…kingpin) and in that very same week we just received a large JDM container with (5) Sti motors. We wanted to step things above the customer’s previous experiences and in doing so had the new motor installed before that week was up! He was ecstatic with a grin ear to ear. Finally the car had power behind its looks. We thought this was the last power level for the car, or so we thought…

Flash forward to May of 2006 when the car rolled through our shop for yet another motor change. This time the owner had plans for bigger power. This included: CP pistons, GT3076 turbo, 800cc injectors, rotated intake manifold, front mount intercooler, and on and on. This time the turn around was not quite 1-2 days, but the end result was definitely head turning. Here is a brief run down of what all was done:

Widebody Polished Engine Bay

Rotating assembly / Fueling

Turbo / inter cooler / manifold

  • Customer supplied Garrett gt3076 rotated turbo kit consisting of: up-pipe, down pipe, turbo.
  • Perrin Front Mount inter cooler
  • Custom iA-Performance TIG welded aluminum tubing to connect the 2
  • Mirror Polished and reversed intake manifold

Drivetrain / Braking

  • StopTech 355mm brakes up front
  • JDM Brembo Rear brakes
  • JDM STi axles / hubs
  • Stoptech SS lines
  • JDM ver7 nonDCCD SURETRAC transmission
  • JDM sti r180 rear differential
  • motul brake fluid


  • Polished A/C, Alternator, P/S housings
  • Coolant reservoir relocation (customer supplied kit)
  • Cusco Motor / Transmission mounts
  • Heat wrap A/C lines and line firewall around turbo
  • Hydra Nemesis ECU

widebody transmission swap

As time progressed the drive train and engine bay started to flow with the wide body appearance. In the end this was one unique machine! Contenders at Hot Import Nights stood no chance as this beast took top honors for Subaru.  Further steps were planned for the WRX including:

  • Cobb tuning accessPORT w/ a blow thru MAF housing (the Hydra was found to be a faulty unit)
  • Suspension and handling enhancements
  • More engine bay work

Sadly, it met a sudden demise on a cold icy morning. The occupants were safe, but the wide body project finally came to an end.  Or so we thought! The bare rolling chassis was sold to a gentleman in Canada who rebuilt the WRX from the ground up using what type of donor you ask??? If you guessed JDM then you were right! This car went full circle and ended up with a JDM ver8 STi complete drive train / motor and a fresh face lift with a 06/07 front end (the wide body fenders were removed). We still can’t believe the journey this magnificent car has experienced.

Unfortunately, I do not know too much about the body kit, but the car’s owner also owns the mold cavities for anyone looking to replicate this look.  Feel free to drop us a line via phone (520.882.2821) or email if you wish to reach him.

Widebody WRX Engine Bay

Widebody Hood with Insert

Widebody Side View

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2011 BMW Goes Low with KW

100% Stock

After months of anxiously waiting, our customer finally received their 2011 BMW 328ix. The first item on the agenda was suspension. This is where KW Suspension came into play with their Varient 1 series coilovers. Their coilover system allows for a smooth & comfortable ride in addition to height adjustments.

Once the dust settled iA-Performance had installed and  lowered the vehicle by roughly 2″ in the front and 1″ in the rear. The overall change is quite noticeable, especially once the wheels were installed. They are Advan RS 19×8.5 et32s Front and 19×9.5 et35s rear. The tires are Conti Extreme Contact DW 235/35/19 and 275/30/19s.  With less than a 1,000 original miles this car has definitely gone through a transformation.

Front and Rear Coilovers Installed

KW Suspension components fit perfectly at each mounting point.  There are no points where it binds, nor were any modifications needed to fit these.

Once the test drive was completed it was time to fine tune the ride height.

With coilovers and Advans installed

Front wheel photo

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Grand Opening of Dyno Shop 2006

With the growing success of Tucson’s Modification scene we decided it was time to Go Big or Go Home. Everyone in Tucson talks about buying a AWD dyno, but apparently we were the only ones that took the plunge (great learning lesson, more to follow on that in later posts).

That brings me to the next question: What better way to make a splash with a new shop location (INA SHOP) & Dyno? With a Grand Opening of course. The following photos will show the events as they transpired that day.  It is interesting to see what shows up when you have an open mind to Import, European, and Domestic cars. We had a handful or rods, buckets, slammed Euro’s, plus a parking lot full of Japanese imports! Our local neighbors came out to help celebrate which included Ride Now Sports, gracious donors of several raffle items, as well as Hooters Restaurant, wonderful food kept showing up. Thanks again to everyone that helped make that day so memorable for all of us at iA Performance!

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mustang blows up

This video marks that CRAZIEST and LARGEST engine failure that our Dyno ever experienced, or most ever will.  The Oil and Coolant clean up took 2 employees roughly 4 hours of time. We even found oil spots 16 ft tall ceiling!

Q: So what caused all of this joy?

A: It seems that one of the pistons melted down which allowed for excessive crank case pressure that ultimately shot through the aluminum oil galley, yes shot right through.

Please note, we simply rented the dyno space. We were not responsible for driving the car nor deciding to stay on the gas. With that said, please enjoy.

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