Revised OEM PCV and Crankcase Breather Tube

06F129101P Front Detail

In my current quest to return some parts back to OEM spec, I’ve recently purchased the latest revision PCV components.  The latest revision PCV valve is “P” with the part number 06F129101P.  There is also another revision of the rear breather tube, part number 06F103215B.  The valves in the latest revisions seem much stronger compared to my old “G” revision.  The check valves are now spring loaded instead of free moving.  I don’t know when they switched to the spring loaded valves because I completely skipped over the 2 or 3 other revisions.

06F129101P Valve Detail

If you’re wondering why I went back to stock, I wanted to remove the catchcan I’ve been running.  An intake manifold teardown by a forum member  revealed that catch cans do little to aid in preventing the intake valve deposits inherent to direct injection engines.  I have also been thinking about the lack of intake vacuum working on the crankcase.  In the catch can setups, vacuum is sourced from intake air moving over the rear breather tube exit.  I think it is a max of 3″ of mercury according to BSH and this occurs in the higher rpms under boost.  At lower rpms, actual vacuum may be much lower.  Too little flow or stagnant flow through the valve cover may allow the blow-by gasses to start forming deposits.  I’ve noticed a little grime building up around the oil cap area, despite the regular oil changes.  The accumulation of these blow by gasses can contaminate oil and deteriorate it much faster as well.  Another side effect of routing all gasses through the rear breather tube seems to be, ironically, more oil in the charge pipes.  If a recirculation type catch can does not catch all the vapors, the rest end up condensing in charge pipes and intercooler.  The stock system sends them directly to the intake manifold to be burned off.  The way the stock system works, it only reroutes vapors through the charge piping and intercooler under boost.  When I installed my throttle pipe, a good amount of oil came pouring out of the pipes.

06F103215B Check Valve Detail

Now oil vapor in the in the intake charge is detrimental to performance.  This is where a catch can does help.  Oil vapor can effectively reduce the octane level of the intake charge and lead to more knock, which would then decrease performance.  I haven’t noticed a performance difference since I switched back to the stock system but then again, my car isn’t exactly a horsepower monster.  It is a compromise situation but after many miles of thought, I’d rather have the stock system deal with the evacuation of the crankcase gasses.  The stock pcv system flows a lot and I don’t think some of the catch cans flow enough.

06F129101P Rear Detail

The stock pcv valves have not been models of reliability, which is one of the reasons catch catch cans have sold so well. Modified and stock cars alike can blow through them.  These newer parts are now several revisions deep and they seem to be much more robust pieces.  The rear check valve in the breather tube looks much better.  The front pcv check valves have a more positive engagement compared to the “G” revision I compared it to.  I guess only time will tell!


BSH Throttle Pipe – Review

BSH Throttle Pipe


The BSH throttle pipe replaces the stock piping from the intercooler to the throttle body.  It has a provision for two water-meth nozzles and a noise pipe connection.  Block-off plugs are provided if you do not need the water-meth bungs or the noise pipe connection.  This is a high quality piece and it really shows how far BSH’s manufacturing methods have come.  The powdercoat is a nice wrinkle black finish, the welds, although still external, are much more uniform and the whole piece feels like quality.  Nice job BSH.


Installation was not too hard. You’ll find all sorts of stories online about how difficult it was to install the throttle body pipe but I didn’t really find it too hard.  It took me about 1 1/2 hours working at a moderate pace.  I followed the instructions for the Neuspeed throttle pipe since BSH includes ZERO instructions in the package.  I did not find any instructions on BSH’s website either.  While not a show stopper, it’s just an annoyance that really shouldn’t be there.  The best way to remove the stock throttle pipe is to undo all the necessary bolts and then remove the piece from the bottom.  I don’t even know if you can remove the pipe from the top.  You will have very little clearance to do so but it is completely possible to remove it without forcing anything.

Fitting in the BSH piece is just the opposite of removing the stock piece.  It’s easier to attach the silicone tubing to the throttle body first and then to install the BSH pipe from the bottom.  It helps to lube up the silicone with a little bit of motor oil.  It’ll become clearer as you go through the install process.  Clearance is very tight, as you can see.  There is only one mounting point on the BSH pipe.  I don’t have a picture of it but it attaches to the bolt that holds a coolant line.  Once I get down there for an oil change, I’ll take a picture.

Once everything is fitted up, double check you clearances and make sure you won’t hit the fans.  The engine does rock when you accelerate.  Check to see if you reconnected the MAP sensor and all the clamps are adequately tightened.

Driving impressions

BSH does not claim hp gains with this pipe.  They advertise it as an easy way to add water-meth spray nozzles and block off the noise pipe.  They also claim increased airflow and better engine response by virtue of the larger diameter piping.  I think I can fully agree with the engine response claim.  The biggest improvement I felt was in the midrange.  The engine just feels livelier, punchier for lack of a better word and feels much less restrained when applying the throttle.  Definitely a lot more fun to kick around town.


I really like what this pipe  has added to the character of the engine.  To me it makes driving the car even more fun.  It’s not a massive fundamental change but I noticed the change in response immediately.  It is a nice option if you want to have a reliable method of installing a water-meth spray system, but I can’t really comment on it because I don’t run water-meth.  The price hovers around 170 dollars and is available from the usual vendors.  A search on Google shopper will find the lowest price.  I really like this part and it would probably complement other intake mods very well.  I am running the stock intake and still found gains.  It is currently the best throttle pipe on the market as it offers a variety of configurations at the same price point as the others.  Recommended.

Product Reviews

I’ve been slowly reworking over some of the older product posts and turning them into more informative reviews.  They’re being compiled on one page.  Click this link or the link at the top of the header to check them out!

BSH Throttle Pipe – A Few More Pictures

Barely any clearance

 Space is a little tight…

You can see how close everything is

While it looks close, nothing actually touches

BSH Throttle Body Pipe – Quick Overview

BSH 2.0T FSI Throttle Pipe

This lovely piece is the BSH throttle body inlet pipe.  The BSH pipe has two built in bungs to make installing water-meth easier.  The pipe supports running the stock noise pipe, a diverter valve relocation or blocking it off completely.  The threaded block-off is sealed with an o-ring.  The theory is that larger diameter piping replaces the stock pipe and reduces restrictions before the throttle body.  BSH does not claim power gains with this part.  They suggests that gains come in the form of drivability with better throttle response and nicer top end.  I’m inclined to believe them.  I’ve had the pipe installed for a few days and engine response has improved.  The biggest improvement I’ve felt is in the midrange.  The engine feels “meatier” for lack of a better word.  It’s nice enough of an improvement that I don’t quite trust myself.  It could be all in my head, but it certainly feels good.  I got mine from DBCPerformance.  This is it on the BSH website.  Look around as the prices vary between vendors.

I’ll have a full review in a little bit, as for now, check out the pictures:

Water-meth bung

Threaded Noise Pipe Block-Off

I think this is the lower water-meth bung, or maybe the map sensor

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.

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.


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.


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.

BSH True Seal Intake

Original article circa summer ’09 – I’ve split the article into its two components: the intake and the diverter valve kit.

This kit is for the 2.0 T FSI engine.

I received this intake kit awhile ago.  The design is top notch and well made.  It includes single piece piping, a heat shield, a proprietary filter, a Forge diverter valve and all necessary clamps and hoses.  Installation is relatively simple if you have the proper tools.  One highly recommended tool is a hose clamp remover.  I think the newer kits are being shipped with them.

After a few months with this kit, I feel that this is the best intake for the GTI out there right now.  It solves the issue of failed diverter valves and relocates the valve itself to the front of the car.  No dyno runs on the intake yet but midrange and the top end feel better.  The torque curve seems to have shifted slightly to the right, but nothing crazy.  This intake is not very loud, if you are looking for noise, look elsewhere.  Otherwise, it’s a nicely designed piece and a great company to deal with.

If you are chipped, you don’t have to worry about any more torn diverter valves.

Review Redux: updated (1/27/2011)

The BSH Trueseal intake for the FSI engine is just one of many intake systems available for the GTI.  There isn’t much deviation as far as filters on a stick go but this one offers a few unique features of its own.  It offers a built in relocation bung as well as a heat shield which isolates the filter from the engine bay.


Sorry for the horrible picture, a much nicer one will be up soon, I promise

The intake itself is very simple with 2.75 inch piping in powder coat black.  The heat shield is relatively thick sheetmetal, also powder coated black.  The edges of the heat shield are covered with a rubber seal that presses up against the hood liner, thus creating a box around the filter.  The silicone and associated clamps are all high quality pieces.  The filter is a proprietary specification that is narrower than most other filters in order to fit into the heat box.  Despite that, a similarly sized filter from another vendor will most likely fit.  It is oiled but I have not had any problems with the oil contaminating the maf sensor.  It has since been changed out for an AEM Dryflow filter which filters better and requires no oil.

I can’t really comment of how much power this intake makes as I have not put my car on the dyno with it.  You’ll probably gain a few horses, nothing to write home about.  Those gains will increase as you pile the mods on though, especially with chipping.  Just don’t believe the +15 hp ads that you see regarding intakes.  It does wake up the engine a little on the high end and provides a very nice sound.  It’s not loud by any means, so if noise is what you want, look elsewhere.  BSH’s intake provides a very mature sound, no doubt due to the heat shield surrounding the filter.

Here’s something important, and since it’s important, it’s going to get its own break.  MAF sensor placement is very sensitive on these cars.  Some intakes will drive the sensor nuts and in turn your car, causing all sorts of chaos.  Fuel trims are adversely affected by incorrect maf calibration.  STFT and LTFT (short term and long term fuel trim) will be incorrect if the maf placement on the intake is off.  There was an early run of BSH intakes that had incorrect maf holders.  The fuel trims are not too bad on these early intakes but in reality you want it to be as close to zero as possible.  If you buy used, be sure to know which version you are getting.  The older maf holder sticks out about an inch or more from the intake.  The newer ones are much closer to the piping.  Reference the following picture of the older MAF holder:

The newer one is much smaller than that.

Older BSH MAF Holder

Finish is not BSH’s strong suit.  The intake is well made and will hold up but doesn’t look the part.  I know it’s nitpicking but it’s all part of the show.  The welds on the intake are very visible and lend a homebrew look to the whole thing.  The relocate bung is sealed with an ugly vinyl cap if you’re not using it.  The rubber seal on the heat box looks like it came straight from your local hardware store.  The intake also doesn’t secure too well in the box.  I eventually added additional rubber to secure it.  There is certainly none of the flash you get from other manufacturers such as AWE, Eurojet, Forge and APR.  If you’re looking for flashy, this isn’t the intake you’re looking for.  For those that are looking for functional bits, this is it.  It has a great heat shield, a built in relocation port and all the growl a normal adult needs.  Despite the visual flaws, the BSH intake still gets a recommendation from me.  It is priced far below the other premium intake options such as the Forge Twintake, and AWE carbon intake and works just as well.

~ 270 from and other dealers

Here’s a link to an AEM Dryflow filter that fits in the BSH heat shield.  The fit is a little tight though.  AEM Dryflow

Revision D Diverter Valve

Part Number 06H 145 710 D


A little while ago, VW released a revised version of the infamous diverter valve.  Now known as the revision D valve, it replaces the diaphragm seal with a much stronger piston type.  Previous revisions (B, C, and G) had diaphragms that were known for ripping and subsequently failing to hold boost.  Some of these failures were under stock boost levels.  The G version is the stoutest of the diaphragm valves with fewer failures reported across the forums.

Of course luck plays a huge role in this.  Some people have reached 30,000 miles on the stock C valve.  I reached at least 45,000 miles on my C valve.  Then again, I tend not to use my right foot aggressively.  If you feel that your car is losing power or making funky noises, pull the valve to check.  Look for tears in the diaphragm.  If you have a boost gauge, it’s even easier for you.  The car will not hold peak boost easily or at all.

The new valve simply bolts right up to where the old one sits.  It seems to have a good track record at the forums.  There has been a report or two of it failing but the causes were unknown.  Maybe a factory defect?  MJM Autohaus currently (1/19/2011) has the best price at $65 shipped.

There are several kits that solve the diaphragm problem by using a piston type mechanical valve, or a vacuum actuated diaphragm valve.  BSH, Eurojet and AWE all sell mechanical kits.  Forge sells one that has ecu control but still relies on vacuum.  I have the BSH valve relocation myself, a great piece of kit but I wanted to hand control back over to the ECU.

Why try this over a mechanical valve?

  • It allows the ecu to control when and how the valve opens
  • Quicker to open when the throttle is released (mechanical valves rely on vacuum and pressure differential to open up)
  • Cheaper (65-90 dollars and no additional parts required)
  • Less hassle at the dealership (oem part)
  • Maintenance free

New piston design

There are certainly arguments for using a mechanical valve such as the ones included in the BSH diverter valve relocation.  A mechanical valve is simpler and pretty much bulletproof.  There are no electronics to worry about, they just work.  In the case of the 2.0t FSI engine (and TSI as well) the mechanical valve is also open at part throttle (under vacuum).  This allows air to bypass the intercooler and turbo and go straight from the intake to the throttle.  This supposedly leads to smoother throttle transitions.  This only works for mechanical valves used in a relocation kit.  I can’t comment on that, I’ve completely forgotten how the car first felt without the BSH kit.  With the kit on, the car ran perfectly well.  Now the exact amount of benefit this provides is debatable but the logic is sound, path of least resistance.

If you’ve tried the new revision, let me know what you think of it in the comments!

Nothing to see here folks

Nothing newsworthy over the past month or so, the GTI is just chugging along at 90,000 miles on the odometer.  I’m still waiting on a special order piece from OEMPLUS.  If all goes well, you’ll be hearing about it soon.  If not, well, that would suck.  It involves the stock air filter/engine cover and a BSH recirculation kit.  The piece should be here any day now…  I did find that DBC Performance offers a good price for 6 quarts of Lubromoly oil, an oil filter and a new drain plug/washer combo.  60 bucks with free shipping!  FREEEEEE!  I gotta be excited for something besides Christmas.

As always, if there are any questions about anything, fire away at the comments!

Wow, this has really been a slow month…