Stock Engine Cover/Intake

Well I’m a fickle person.  Over the course of the past week and a half, I’ve been tinkering with my intake and diverter valve setups.  I think I’ve finally settled on one; stock.  I know it is quite an about face, but I’ve come to the realization that the stock setup is actually quite good and does not detract from power.  It has excellent filtration, a good source of cold air, and is excellent at avoiding water intake.

 

The stock engine cover, not exactly your worst enemy

MAF Design

The stock engine cover uses an oval maf sensor housing, one that isn’t easily duplicated in aftermarket housings.  In fact, I don’t think there are any aftermarket intakes that accurately mimic the stock housing.  Round intakes can come close but not 100%.  The necessity of 100% accuracy is debatable but the closer you are, the better.  Fujita ignored this and was rewarded with the worst performing intake for the MKV.  Wholly inaccurate maf measurements and worse performance.  Even certain versions of the BSH diverter valve kit threw the maf sensor readings off, not to the degree of the Fujita, but enough to reduce performance.  The stock housing also contains a flow straightening screen which helps the maf read air flow as accurately as possible.  In short, you do not want inaccurate maf readings.

 

Oval tube and flow straightener

Inaccurate maf readings can lead to a multitude of problems such as reduced performance, poor gas mileage and poor throttle response.  Most of these result from messing with the short term (STFT) and long term (LTFT) fuel trims.  Here is a good article from Ross-Tech explaining how fuel trims work: Fuel trim info.  Basically you want to keep your trims around as close to zero as possible.  STFT has a +-5% range while LTFT is +-10% I believe.  I’m not so sure on the LTFT.  If you exceed these ranges, your performance will begin to suffer.

With the stock intake, my STFT is less than +- 1% and the LTFT is less than +-2.5%.  The aftermarket intake showed trims of -2.5% and around 5% respectively.

 

Maf position in stock intake

Stock vs. Aftermarket

The stock intake feels much better down low.  Chalk it up to the MAF area design or location but I cannot deny that it feels much more responsive down low.  The metal of the aftermarket intake pipe may be absorbing heat when the car isn’t moving.  In the upper rpm range, the aftermarket intake feels like it pulls harder/better.  It’s possible that an advantage in air speed may show up once the engine starts requesting more air.  Another possibility is that the airflow in the tube becomes less turbulent as speed increases, allowing the MAF to read the mass correctly.

Filtration is one area where the OEM intake will always win.  As good as the AEM filter may be, it is not going to beat the OEM cellulose filter.  The stock filter also has a huge amount of surface area, with more material and pleats than the aftermarket filters.

The noise difference is not drastic between the BSH and stock intake.  The BSH is already one of the quietest intakes and stock is well, stock.  BSH’s intake does have a deeper growl.

Why would you want stock?

I’m not going to say that aftermarket intakes have no place.  I’m just reorganizing the priorities for my car.  If the stock intake can provide me with 98% of the performance of an aftermarket intake, why not?  I ran an aftermarket intake for around 40,000 miles.  It has certainly served me well.  I just like to tinker with things.  Nothing purely scientific, I know, so take my experiences for what it is. But you can be sure that the MAF area has certainly caught my eye and a lot of engineering did go into the design of the cover.  I’m just deciding that they did a pretty good job.

Spark Plug DIY

Here’s a spark plug diy I wrote for the MKV 2.0T.  Hope it comes in handy for you do it yourself types.  If there are corrections that need to be made, drop me a comment.

Spark Plug DIY

BKR7EIX Tip

New OEM Spark Plugs – 06H 905 601 A / NGK PFR7S8EG

 

New OEM Plugs

There is a new part number for the OEM spark plugs – 06H 905 601 A.  They are made by NGK now instead of Bosch.  The corresponding NGK part number is NGK PFR7S8EG.  This new plug is a double platinum laser plug that is also one step colder.  I guess all those people advocating one step cooler plugs were correct.  Anyway, I installed these last night and the engine is purring as always.  The BKR7EIX’s I had in there had begun to show erosion at the ground electrode and the gap had opened up considerably.  I did not notice any real change in performance, slightly smoother idle is pretty much it.  I’ll report back if it affects mileage considerably.

This plug supercedes part number 101 905 631 H which superceded 101 905 631 B.  The previous part was a Bosch FR6KPP332S.

Anyway, here are some pictures showing the new plugs.

A DIY is located here if you need it.  >DIY Spark Plug Change

*Update*

Some more information regarding the newer OEM NGK sparkplugs from a forum member on Golfmkv.com:

When comparing to a bosch stock plug many goof on the difference in how their ranges work. Because of that some cross references out there show the 6 heat range NGKs being stock. If you go to NGK themselves and check THEIR application guides it shows a heat range 7 as being stock.

06H 905 601 A / NGK PFR7S8EG

06H 905 601 A / NGK PFR7S8EG

06H 905 601 A / NGK PFR7S8EG

New OEM Plugs

06H 905 601 A / NGK PFR7S8EG

06H 905 601 A / NGK PFR7S8EG

06H 905 601 A / NGK PFR7S8EG

Revision D Diverter Valve – Stock Location

Well it’s official, I’ve gone nuts.  I went back to the stock diverter valve location after all the time I spent thinking about diverter valve relocations.  The mechanical valve was nice but I wanted ECU control.  The ecu controlled relocate was nice but required some rigging to get it to work with the stock intake.  So I’ve gone full circle and landed back at a nearly stock intake system setup.  My stock intake is back in, and the diverter valve is back in its original location.

 

New piston design

Initial impressions are that the D valve feels better in the stock location than in the relocated position.  Maybe something was leaking?  No logs yet, they will come eventually.  Boost response felt a little “off” with the valve in the relocated position.  It bogged sometimes and the car felt labored in the very low rpms.  The boost ramp up was a little strange, it felt like it would spec too much boost at a low rpm.   I should have run some logs but didn’t think of it at the time.  With the valve in the stock location, boost response feels better and is more linear.

There are a handful of reports stating that the valve does not seal correctly on the FSI, leading to decreased throttle response and delayed boost peak.  The cause was never determined but in most cases the problems were resolved by switching back to a diaphragm version.  It could have resulted from a faulty valve or improper installation.  My valve seals and functions just fine.  The summer heat should really put the valve to the test, we’ll just have to wait and see if it holds up.

I think Volkswagen and Pierburg (manufacturer of the actual valve) have finally come up with a bullet proof solution to an annoying problem (torn diverter valves).  The valve is maintenance free and if it proves reliable, is perfectly fine for a mildly tuned 2.0t.

Oil Change With Pennzoil Platinum Euro 5w-40

I finally filled up the GTI with this.  Car feels nice and smooth again, although that darn placebo effect is always lurking.  The old fill was feeling a little tired (Lubromoly Synthoil Premium 5w40) and I was only a little off from the interval so I decided to throw it in.  The Lubromoly Synthoil Premium is different from the older Lubro 5w40.  It is no longer fully synthetic, I supposed due to cost cutting, and the car did not seem to like it as much.

The car feels smooth on the new Pennzoil Ultra fill, too bad it is so pricey.  Even so I might switch to this as my new regular fill, unless I find a stock of the old Lubromoly.  I will try to swing an oil sample on this interval to see whether the car truly likes it.

Pennzoil Ultra Euro 5w40

 

AEM Dryflow Filter

If you are interested in replacing the filter on your aftermarket intake system, give AEM’s Dryflow filter design a try.  The filtration media is designed to work dry and requires no oiling.  It’s easier to clean than the K&N oiled filters and is supposed to filter better. Since it uses no oil, it avoids the risk of over oiling the filter and contaminating the MAF.  This is admittedly a rare occurrence if you take care in re-oiling a K&N.   The oiled filter design flows better but I’d sacrifice some flow for filtering any day.  The filter muffles intake noise a bit more than the standard oiled filter so keep that in mind.

This particular filter was fitted to the BSH Trueseal intake.  Take note that the BSH filter is a very narrow design.  The AEM fit there is not much clearance.  It ends up contacting the liner on the hood, not too badly, but it is something to keep track of.  The correct size is a 2.75″ inlet and 5″ length.  I think the part number is 21-202DK.

It is interesting to note that AEM’s Dryflow filters now also have the K&N logos on the box.  The filter division was bought out a little while ago, but nothing seems to have changed, save for the color (now red instead of gray) and the addition of a metal mesh(originally plastic reinforced).  AEM has another line (Bruteforce Dryflow) that maintains the design of the original Dryflow with gray filter media and internal plastic reinforcement.

Pennzoil Ultra Euro 5w40

Pennzoil Ultra Euro 5w40

This is a bottle of the so-rare-it’s-magical Pennzoil Ultra Euro in 5W-40 grade.  You are all but guaranteed not to find this stuff in any brick and mortar stores.  I had to order this direct from the Pennzoil site.  It is quite pricey at $50 for six quarts but is reported to be a robust oil.  It has a long list of approvals, including VW’s 502/505 and Audi’s 503.01 spec.  I haven’t poured this in yet, I’ll be trying it out for the next oil change.

OEM Approvals

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Aftermarket Filter Options – K&N HP 7010

K&N HP 7010

Practically all of the aftermarket filters for the 2.0T FSI engine are made by the same two manufacturers:  Hengst or Mann.  Here is K&N’s version of the Mann filter.  The part number is HP-7010 and has the made in Germany stamp you need to look for.  The filter comes with a new gasket as well.  Ten dollars shipped from Amazon.com.

Made in Germany

If you need a local source, a Fram replacement is also available.  Fram CH9911 Note the identical design of the Fram.

Fram CH9911

BSH Diverter Valve Kit – Review

 

Forge Diverter Valve

The BSH kit is well spec’d and doesn’t scream aftermarket even with the large Forge valve dominating the view.  Granted it does ruin the illusion with the requirement of an aftermarket intake but it’s forgivable.  BSH had a few performance goals with the installation of the kit:  better part throttle engine response and reliability.  It hit both of these targets.  Lets go into more detail as to how it reaches its goals.

BSH uses the noise pipe as a recirculation pipe, routing to big Forge valve in the front of the engine bay

Better Part Throttle Response

This one seems to baffle people the most.  How can installing a replacement valve result in better response?  To answer that we need to delve into the details of the stock system.  The stock 2.0t diverter valve resides on the compressor housing itself.  This is not a bad design.  It is very efficient in terms of packaging and cost.  No need for extra hoses, pipe and other support hardware.  However, it does require the airflow to go through the intercooler when not under boost.  The BSH kit reroutes the air flow through the stock noise pipe, bypassing the intercooler and routing air straight to the throttle pipe when the engine is not requesting boost.  The mechanical operation of the Forge valve keeps it open under vacuum.  Shorter path for airflow – slightly better part throttle response.  Under boost pressure, the valve is closed and air follows its normal path through the intercooler.

Practically Unbreakable Forge Valve

The Forge valve used in the kit is massive.  It carries 1.5″ ports to match up to the stock noise and throttle pipe inlet/outlet.  The valve controls airflow with piston design instead of the diaphragm stock valves.  (Note that newer D revision valves now use a piston as well)  Constructed out of aluminum, this will last the life of your car and then some.  You can rebuild the valve several times over.  The only downside is that you’ll have to grease the valve occasionally.  Regreasing is a quick procedure that any owner can do at home.  Mechanical valves are also slower to react than electrical, but it seems to be a none issue in this kit.  The vacuum source is provided with a boost tap on the manifold.  Because of the short length of the vacuum hose (less than 5 inches) reaction time is quite quick.

Overall Design

As with most of BSH’s designs, this one isn’t pretty or gussied up.  It’s very functional and to the point.  There are no fancy pieces to decorate the engine bay.  Even the boost tap is anodized black.  You get a few specific silicone hoses and then the shiny Forge valve.  Very clean look overall as it utilizes a few stock components such as the noisepipe and and one of the hoses.  Not fancy, but it gets the job done cleanly.

Installation

The installation is not too difficult.  Follow the instructions on BSH’s site and you should be good.  It requires a few tools so make sure to have those before hand.  Here are a few suggestions though:

-The wipers do not have to be removed to move out the noisemaker/speakerbox.  In fact my wipers were frozen onto the posts.  Just a little careful lifting around the rain tray will help you.  I actually just left it in there and just disconnected the hoses I needed.  You can do that too and it will help when you have to reinstall things back to stock.

-The diverter valve blockoff will require removing the diverter valve bolts which are a 5mm hex.  Use a 1/4″ ratchet with a short extension maybe.  It’ll help immensely.

Other than these few tips, just take your time and don’t rush.  The proper tools help a lot.

Grade?

I really like this kit.  It does it’s job and does it well.  The sound the valve puts out is nice and not too loud.  It’s rather addicting actually.  It has everything you need to put it all together.  It solves your diverter valve issues and provides a nice performance uptick.  The only knock on the kit I can find is that it requires an aftermarket intake.  And if you don’t have the BSH intake with it’s built in bung, you will need to hack off a portion of the rear to fit BSH’s own rear section.  It’s not difficult but other competitors have figured out ways of using your aftermarket intake without cutting.

AWE Diverter Valve Relocation – Review

I recently switched my diverter valve setup from the BSH relocate kit to the AWE stock diverter valve relocate kit.  What’s the difference?  AWE’s kit uses the stock electronic diverter valve instead of a mechanical (Forge) valve as in the BSH kit.  Doing so allows the ECU to control when the valve should be closed and when it should be opened.  Not that I was unhappy with the BSH kit.  Not at all.  It’s a great setup, but I wanted to use the revision D valve in a relocate.

Overview

Enter the AWE kit.  This is a very well done kit.  Very simple and rather ingenious.  I’m impressed with the execution.  This, in my opinion of course, has to be the easiest relocate setup to install.  The parts are all of very high quality and fit precisely.  I did break the larger hose clamp.  I probably over tightened it but it may be something to keep an eye on.  This kit does not include a diverter valve.  You either reuse your stock one or purchase a revision D valve to go with it.  I did the latter.  The stock intake will not work with this kit unless you have the TSI motor.  You will need to have an intake with a diameter of 2.75 inches.  No worries as this is a very common intake size.  Just be sure to check.  The valve adapter is an anodized piece and works with any oem valve.  The firewall gasket is what you will not find on most other relocation setups.  It’s an oem part but the fact that AWE included it for convenience is very cool.  Silicone hoses are pretty much standard, if not a little thicker than the silicone BSH uses.  This kit is for all intents invisible to the untrained eye.  Just about the only visible aspect will be your aftermarket intake and the one piece of silicone that leads to the noise pipe.

Stock photo from AWE’s website. I labeled the parts.

Installation

The most difficult step when relocating the diverter valve is removing the connection to the noise maker piece underneath the rain tray.  I absolutely hate spring clamps.  Fortunately for me, I did this step when I installed the BSH kit.  AWE’s website has a PDF of all the complete steps.

Other than that, installation is very straightforward.  A 1/4 inch rachet and socket set will help make everything go smoothly when removing the stock diverter valve.  The diverter valve bolts are a 5mm hex.  A needle nose vice grip will also help with the spring clamps.  Nothing too tricky on the tool side.  Just be sure to have all your tools lined up beforehand.

Revision D Valve and Adapter

Driving Impressions

So far I have not noticed much of a difference from the BSH kit, as you would expect.  This kit is definitely quieter and I do somewhat miss the noise of the gigantic Forge valve.  I feel like the boost comes on differently but I can’t validate it without doing logs.  It feels like it comes on a little less progressively.  This could be due to the way the ECU operates the diverter valve.  Under most conditions the stock valve is closed, unlike the mechanical valve which is open under vacuum.  This doesn’t allow the engine to draw air through the noise pipe as often as the BSH kit does.  I would give a very slight edge to the purely mechanical setup in terms of throttle response.  Other than that, little difference from the BSH kit.

Why should you get this?

It all depends on what you want.  If you want the ECU to maintain full control, get AWE’s kit.  I suggest picking up a revision D valve to run with it.  If you want a mechanical setup, and especially if you have the BSH intake, go with the BSH.  I would recommend the BSH kit only with their own intake.  The ports are all matched up and you don’t have to cut anything.  BSH might be phasing out the standalone version of their kit, I haven’t seen it on their website lately.  I’m sure they still have it but you have to place a phone call.

AWE can also equip the kit to work with a mechanical valve but I can’t comment on how that performs.  I assume it will work similarly to the BSH kit in terms of mechanical valve throttle response.

Grade

I really like this kit.  Clean installation, great design, and relatively cheap compared to the other relocates.  It is practically indestructible with the D valve.  It also maintains ECU control.

This kit is highly recommended.

Noisepipe to turbo inlet coupler connection