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2Addicts | BMW 2-Series forum Technical Topics N20 (228i) / B46 (230i) Engine, Transmission, Exhaust, Tuning GFB T9357 DV+ Diverter Valve Kit

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      07-21-2015, 01:31 PM   #1
wmandra
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GFB T9357 DV+ Diverter Valve Kit



Disclaimer: I am not responsible for any damage to you or your car. This is not a simple bolt on installation - DO NOT ATTEMPT without the correct tools!

Background:

With a more aggressive custom flash tune for the track on my N20 from GSR Autosport I started running into occasional limp mode issues. When performing diagnostics on the codes thrown when the limp modes occurred, it was becoming clear that there was a boost leak somewhere in the system. This wasn’t at all surprising given I blew apart the OEM charge pipe between the turbo and intercooler. Charge pipe replaced, we began pressure and smoke testing the entire system but couldn’t find the culprit. By chance, I happened to be cruising on the highway in 6th gear at about 50 MPH and noticed something strange when I went to WOT… I could actually hear the factory diverter valve opening and dumping pressure when boost got really high. The reason I didn’t notice this earlier is that the exhaust (basically straight pipes) is very loud and at higher rpm the exhaust noise was masking the intake sounds.

In this post I’ll provide a walk through of how to install the GFB DV+ kit on the BMW N20 along with my thoughts and review on how it performs vs the OEM setup.

Link to the GFB T9357 DV+ Diverter Valve Kit: http://www.gfb.com.au/products/blow-...cations-by-gfb

OEM Diverter Valve:

The factory diverter valve is an electronic solenoid mounted directly to the turbo housing on the inlet side. Because this unit is controlled electronically by the DME, attempting to disable it and replace with a mechanical style BoV will result in errors and the electronics going into reduced power mode disabling the turbo system. The basic theory from tuners in the VW community was that the OEM diverter valves are built with a spring and plastic shroud which are only designed to hold factory levels of boost. Once tuned, the increase in boost pressure may force the OEM valve to open, bleeding boost at full throttle.

GFB T9357 DV+ Diverter Valve Kit:

Thanks to a good friend of mine, HYDE16 in the VW community, I knew that they had a solution to the same issue where the factory diverter would not be able to hold much more than factory pressures before opening. The first part of this solution is an upgrade to the factory diverter valve from Go Fast Bits called the DV+. After a quick email introduction to the guys at GFB I learned that they did indeed have a DV+ kit for the N20, but that nobody had been able to actually get it installed (more on that later). Luckily I have access to the ISTA/d BMW software and enough experience working on the N20 engine that I felt comfortable attempting to get the DV+ installed.

GFB Explains the Benefits of the DV+ Kit:

GFB expands the DV+ range with a direct-fit solution for the weak factory diverter valve used on many European vehicles. The solenoid coil itself from the factory-fitted valve is great (the ECU opens it faster than any pneumatic valve so why replace it?), but the weak point however is the valve mechanism itself. So GFB’s DV+ solves this problem by replacing just the valve parts with an anodized billet aluminum housing fitted with a brass piston machined to exacting tolerances. The end result is sharper throttle response, lightning-fast valve actuation, and it will hold as much boost as you can throw at it. Read all about the DV+ story on the next page. Other manufacturers’ products involve replacing the entire system with a traditional pneumatic valve, requiring long vacuum hose runs, additional parts for tapping into the intake manifold vacuum, plus either a different solenoid valve to actuate the pneumatic valve or a ballast resistor to plug into the OE wiring loom. All these additional items result in a product that is slower, less responsive, more expensive and takes much longer to install. GFB’s DV+ solution on the other hand is more responsive, less expensive, easier to install, and doesn’t cause compressor surge/turbo flutter. Oh, and it doesn’t require different springs or frequent re-builds.

-Retains the factory solenoid coil for seamless integration
-Replaces plastic valve parts with metal for reliability and strength on chipped engines
-Direct-fit replacement with GFB’s TMS benefits
-Exclusive “pilot-actuated” valve mechanism for rapid response at high boost


What’s in the GFB T9357 DV+ Diverter Valve Kit:

Upon opening the box containing the kit there is no doubt that this is a high quality product with quality machining and a flawless finish.



Installation Overview:

This is not the simplest of installations to perform, so give yourself plenty of time to do the work. Installation should take between 4-6 hours to complete.

There are essentially 2 ways to perform the installation. The first method, which I won’t cover in this post is to completely remove the exhaust manifold and turbo from the vehicle. The second method is described below and enables you to complete the install with the manifold and turbo remaining in the car.

Before even thinking about attempting this, read the instructions below completely. Especially the section on loosening the exhaust manifold. If you get this wrong you can cause serious damage to either the turbo, block or cylinder head! You’ve been warned.


Basic Tools Required for Installation:

1/4 inch drive - 6mm, 8mm & 10mm sockets
3/8 inch drive - long round tip 4mm and 5mm hex bits (probably the most important tool to have - see picture below)
Flat head screwdriver
telescoping magnet
Needle nose pliers

The key to doing this installation without removing the turbo:


Additional Tools Possibly Required:

(Only needed if exhaust manifold needs to be loosened for additional clearance, see below)
3/8 drive 11mm deep socket and universal joint
Metric E-Torx sockets
Oxygen sensor socket
Long pry bar
High quality torque wrench

Preparing for Installation:

Note: If you have a habit of dropping tools into the engine bay, it can be helpful to put the car up on jack stands and remove the under tray first.


Start off by using the 6mm socket to loosen the 2 worm clamps on the clean air intake pipe between the air filter and turbo. Once both clamps are loose, remove the pipe from the engine bay.

Remove the electrical connector going to the heater in the PCV vent host. Remove the PCV vent hose by pressing in on both clips connecting the hose to the valve cover, then release the 2 clips holding the heater into the clean air pipe.

Unlock the crankcase ventilation line from the clean air pipe by pressing in on both sides of the connector at the same time and pull straight up.

Next, remove the 2 10mm bolts holding the coolant reservoir in place. Lift the reservoir straight up to release the pin underneath, then disconnect the sensor on the underside of the reservoir. You should now be able to rotate the reservoir to the area between the front of the engine and radiator giving you a little more room to work.

Use a flat head screwdriver to unclip the charge pipe from the turbo outlet. You don’t need to remove the clip completely. Push the charge pipe forward towards the intercooler so that the pipe clears the turbo then slide towards the passenger side so its out of the way. You don’t need to remove the pipe completely.

With a 10mm socket, release the nut holding the remaining portion of the clean air pipe onto the turbo intake. This can take a bit of patience, be careful not to drop the nut into the under tray. With the nut removed, rotate the coolant reservoir back to its normal position and remove the clean air pipe by pulling it straight out of the turbo.

Disconnect the electrical connections to the factory diverter valve solenoid and wastegate. (Note: I’ve only installed this on an N20 with an electronic wastegate, I’m not sure if the vacuum controlled wastegate will be in the way of installation.)

At this point, take a break and grab something cold to drink as you are done with the easy part.

Removing the Factory Diverter Valve:

The factory diverter valve is held in place by 3 screws, 2 of which are fairly easy to access. With the coolant reservoir moved out of the way again use the 4mm round tip hex to remove the top screw closest to the wastegate (this is the easiest one).

The second screw is located underneath the diverter valve and again is fairly easy to access. Remove this screw being careful to not drop it into the under tray.

The final screw is the most challenging one to remove and the reason why you specifically need the round tip hex bit. Without the round tip bit, there is simply no way to remove the third screw without removing the entire turbo from the car. You have to enter with the bit from a pretty severe angle due to the timing chain tensioner blocking access to the screw. Just take your time…. Use the magnet to remove the screw once it has been completely loosened.

At this point it should be possible to remove the diverter valve by sliding it all the way back from the turbo (towards the front of the car) and then slide it down into the space where the intake pipe connected to the turbo. It’s a really tight squeeze and may require some jiggling to get it out.

If you find yourself stuck at this point unable to completely remove the diverter valve don’t force it. Grab another cold one and take a quick break…

Loosening the Exhaust Manifold:

If you were able to successfully remove the factory valve above, you skip this section. If the valve just won’t come out no matter what, you will have to loosen the manifold and lightly use a pry bar to open up enough space for the diverter valve to drop out.

First, use the E-Torx sockets to remove the strut tower brace from the engine bay. Then use the 8mm and 10mm sockets to remove all the screws and nuts holding in the heat shield. This is necessary to create enough room to access the exhaust manifold bolts.

Using the 11mm deep socket and the image below, loosen all bolts connecting the manifold to the head in order from (10) to (1). Do this in multiple passes, loosening all the nuts a little more each pass until all (10) have been completely removed.



If nut (6) is blocked by the oxygen sensor on the downpipe, disconnect the sensor from the harness and remove using a O2 sensor socket. Be careful not to damage this sensor!

With the manifold nuts removed, place a long bar between the wastegate bracket on the turbo and the timing chain tensioner housing on the head. Apply light pressure to move the manifold away from the engine enough so that the diverter valve can be removed.

WARNING: Do not apply too much force to the pry bar! The turbo is still connected to the engine by 2 hard oil lines that can break.

Disassembly of Factory Diverter Valve:

With the diverter valve removed from the engine, follow the instructions included in the kit to remove the piston, spring and piston basket from the OEM solenoid with a pair of needle nose pliers. Be very careful not to damage any of the components upon removal or reassembly back to stock will not be possible without purchasing a new diverter valve from BMW.

Here’s a picture of the parts that need to be removed from the solenoid:


While you have the solenoid out of the car on the bench its a good idea to test fit the new components. Start by inserting the new spring and plunger into the solenoid then press the DV+ onto the solenoid. There is a plastic pin next to one of the holes in the solenoid which will line up with a recess in the DV+ if the orientation is incorrect the solenoid will not properly sit flush on the DV+.



Take another break, grab another drink - you’re now more than half way done.

GFB T9357 DV+ Configuration / Tech Tip:

The GFB DV+ can be configured in two different ways depending on you own personal preference. During assembly, you can choose to install the main piston spring (indicated by the arrow) or not. For my installation the main piston spring is installed in the DV+.



Using the spring is recommended because it results in the best possible throttle response and minimum lag on gearshift, particularly on manual cars. This can sometimes result in a slightly different sound from the intake at low RPM, which is no cause for alarm - it’s simply the different way in which the valve works. If however the noise is objectionable, removing the spring will make the DV+ operate the same way as the factory valve, albeit at the expense of throttle response.

To explain further, minimum lag on gearshift on any petrol turbo engine is achieved when the diverter or blow-off valve vents only just enough air to prevent compressor surge. Venting more air than necessary increases lag on gearshift because the intercooler is completely relieved of pressure, meaning it takes longer to return to peak boost when the throttle is re-opened.

The DV+ is no exception, because unlike the factory diverter, the DV+ opens and closes in response to both the DME command AND the amount of boost pressure in the intercooler. So when the DME triggers the solenoid, the DV+ piston will only open as far as the boost pressure in the intercooler can push it against the spring. The factory diverter on the other hand will simply open regardless of the boost pressure.

The different sound on throttle lift at low RPM is simply because of this different operation method, and it does not adversely affect the turbo or engine. Removing the spring means the DV+ piston will simply open and close when directed by the ECU, just as the factory diverter does.


Installation of DV+ and Solenoid:

Due to the clearance available, you will not be able to re-install the solenoid with the DV+ attached. Go ahead and disassemble the DV+ and solenoid making sure to not mix up the plunger spring from the kit with the factory spring you removed earlier.

Insert the main piston and spring (if used) into the DV+ housing and install the housing onto the turbo from the top. It will not fit through the opening on the bottom where the solenoid was removed from. Be sure to align the DV+ so that the recess for the plastic tab on the solenoid is located at the top hole closest to the wastegate.

Re-install the solenoid into the space behind the DV+ from the bottom front of the turbo just like it was removed. Once the solenoid is in place insert the new plunger spring and plunger into the solenoid and press the solenoid firmly in place against the DV+. Again, ensure that the plastic pin on the solenoid is sitting in the machined recess and is orientated so that the pin and recess is at the top hole closest to the wastegate.

Use a magnet to guide the supplied longer screws into the 3 holes then tighten them using a 5mm round tip hex bit. Do not tighten each screw fully, but instead use multiple passes across all 3 screws making each progressively tighter as you go.



Reassembly:

Congratulations!! The hard part is over, all that’s left is to put everything back together.

Start with the exhaust manifold nuts installing in order from (1) to (10) using the picture below. Torque each nut in order to 8 Nm, then tighten each nut in order to 13 Nm.



The remaining reassembly is the reverse order of removal and is simple enough that I won’t go into detail here. Don’t forget to reconnect all the electronic connectors including the sensor under the coolant expansion tank.

Some Initial Thoughts:

So far I haven’t really had enough time to fully evaluate the GFB DV+ Kit, but some quick pulls on the highway (within the speed limits) yielded no adverse effects. During low RPM 6th gear pulls boost pressure holds at its peak level and no noticeable noise of the valve opening can be heard anymore. I will reply with a more thorough review with data after I test it on the race track this weekend.
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      03-31-2016, 11:24 PM   #2
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I installed and i realize it actually make my car throttle response slow and the turbo sounds more obvious when off the pedal ( as mentioned above)

Can anyone help?
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      04-18-2016, 04:21 PM   #3
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      05-01-2016, 10:19 PM   #4
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Quote:
Originally Posted by ROBNYC
Stubok
@Raytec85 Certainly didn't make my response slower. Quite the contrary, but I did go with the extra spring.

Not sure you can really install it incorrectly. Maybe without the added spring it's the same speed as the old poppet, but it's faster with the added spring.

If any of the seals are leaking, that could be a reason.
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      09-06-2019, 03:00 PM   #5
bathsaalts
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For the amount of work it seems to take to install it, would you consider it worth it? Is the benefit really just better turbo sound? I just bought one and now I'm starting to think I should maybe refund it
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      10-30-2019, 10:52 AM   #6
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One benefit I never seen mentioned that I got from it is better fuel economy in city driving. Traffic is a nightmare where I live and my car was around 18L/100Km before DV+, now is at around 13.5L/100Km, so I'd say it will pay for itself from just daily driving economy.

I have it installed in the car for about 3 months now, throttle response is better and no bad side effects so far.
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