Go Fast Bits (GFB) DV+ Upgrade Review for 05.5 B7 A4 2.0T FSI + Installation notes

[shahk62]

Hi Guys

Hope I'm following all the rules and stuff regarding new posts but here's my first product review. Note - I am not sponsored by GFB and have not been approached by them to do a review This is a great first mod and is about a 2 on the difficulty scale out of 10 and should take maybe 30-45 minutes depending on skill. I've owned this for about 3 months prior to writing this so hope you find it useful.

As the subject suggests I'm looking at the GFB Diverter valve upgrade which is available across the FSI/TSI range of engines for VAG.
http://www.gfb.com.au/products/blow-...cations-by-gfb.



To begin this - I guess for those who do not know what the function of a diverter valve is - in turbo charged vehicles the turbo is pressurizing air before it enters the intake which allows for higher powered combustion. Now if this was a perfectly closed environment - this would be okay if you were constantly flooring it and never lifting off or braking because the pressurized air would be constantly flowing into the engine! However in reality we have to lift off and in that situation what would occur is the pressurised air having no where to go into the engine and isntead begin to flow the other way back into the turbo charger which causes what is known as compressor surge (which is bad). Many instances of this happening would eventually result in sever damage to the turbo-charger. - Introduce the diverter valve! This essentially is a valve which opens and closes depending on the throttle position i.e. - opens when not accelerating or when boost is required to be released and closed when the engine wants to boost.

So from this I guess it's worthwhile just touching on the stock types in VAG vehicles. Both types contain an ECU controlled solenoid which is what drives the opening and closing of the valve (which works fantastically)- however there are two types of valve designs which are used - both of which have their own inherent weaknesses.

Diaphragm type - mainly on earlier B7 vehicles

This one by design is the better of the two as it has a much tighter seal from the rubber used - however it's this rubber which also makes this valve the less reliable of the two (p.s. broken rubbers aren't good). Particularly if you drive aggressively or have a chip tune which calls upon in higher boost it is highly likely you will rupture it at some point.

Piston Type - newer variant

Instead of a diaphragm to seal boost in - this valve contains a plastic piston which does not seal as tightly as you would hope - however is the choice of many for most.

The product

This brings us to the product at hand to be reviewed - the GFB DV takes what is good about the stock diverter valve - (the solenoid) and replaces the rest with it's own high quality silicon and brass piston type design while also adding in an additional spring to more rapidly close the valve resulting in faster spool up times and less turbo lag!

The product is made in Australia and retails for about 140 USD + shipping. It comes very professionally packed and straight away when you open it the quality of the workmanship and the parts is fantastic.
For the Install I used http://www.gfb.com.au/phocadownload/...structions.pdf - can also use this as a reference http://www.audizine.com/forum/showth...l-Installation

These are fairly good and essentially
1. get the car onto jack stands or drive car onto ramps (chock wheels for safety)
2. undo belly pan (phillips heads)
3. unplug connector to stock diverter valve (on drivers side underneath car)
4. using 5mm allen socket undo 3 bolts holding it in
5. pull on diverter valve to take apart components
6. reassemble using GFB kit
7. Reverse to install

The installation was quite easy with the hardest thing being getting to the top bolt (mainly because you can't really see it and so have to do by feel) but it is not too challenging an ask.

Putting together the upgraded unit was quite easy and just have to make sure you are following all their instructions and ensuring you re-use the O-ring they mention. The hardest thing if anything now was just keeping it together when reassembling back onto the car as it is now properly spring loaded (which is where the performance increase comes from).

For me the installation was a night and day difference even though I am in a tiptronic car - for manual owners between gearshifts on stock systems would suffer from much more significant turbo lag as the liftoff would result in boost being lost and the DV not closing in time. The car feels preppier and much more happy to go into boost, there is a slightly more audible "blow-off" sound and I have noticed that there is much less lag before going into boost.

Final Recommendation/Verdict (9 out of 10)
This is a fantastic product and great way to upgrade your DV before chipping your car or using the car for any performance driving - especially if you are lucky enough to have a manual transmission. The fact it reuses what works in the stock system saves significant costs compared to say forge and essentially gets the best of both worlds for the system in that it is an all metal design, it holds boost better & still has the same rapid response of the stock units. My only qualm with the product is that it is a slight pain to keep together when installing and so if there was something to hold it together better before going on it would make life that tiny bit easier but other than that it's all smiles from here!

Hope you guys found this useful

[brandonpham]

Awesome write up. Good job!

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[UberTeile]

For me the installation was a night and day difference even though I am in a tiptronic car

Agreed, the DV+ has been my best bang-4-the-buck mod to date. These should have come on the car from factory, IMO.

[Okedokey]

Agreed, the first thing I installed. Great to see an Australian company producing such things..

[vvenom800tt]

Im enjoying mine

[jimrobbington]

Best dv option the b7 has!

[vce1232000]

Ive this going on 2.5 years and not a single problem or thrown code.. Noticed a difference in holding psi between shift points over stock

[DanKing]

Can the GFB upgrade only fit on the OEM Piston style DV or can it also work with the Diaphragm style DV??

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[shahk62]

Can the GFB upgrade only fit on the OEM Piston style DV or can it also work with the Diaphragm style DV??

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Works wth both. Between the two variants there are no differences between the housing or solenoid. It just the valve components which are different.

[oVeRdOsE]

I think you've rise the point, but if I can add.

OEM diverter, if I'm not mistaken, got a bi-electric signal. 0V or xxV. Means that the solenoid is 100% load or 0%, means that the diverter should open 100% or close 0% because of the low spring load and solenoid electrical load..

GFB diverter+, add a mechanical ''value'' to the setup. Which means, depending of the boost load, it will open/close under the solenoid and the system air pressure more precisely.

Let say you leave the gas and press if right after (quick shift), opening the DV at 100% will let the pressure system to go way to low than needed. But, DV+ can hold back and open i.e. 20%, and ready to take the turbo pressure back on quick shift.

= less lag, faster boost and throttle response.

( this is my understanding of the concept of this DV, you can correct me if needed)

[Okedokey]

I think you've rise the point, but if I can add.

OEM diverter, if I'm not mistaken, got a bi-electric signal. 0V or xxV. Means that the solenoid is 100% load or 0%, means that the diverter should open 100% or close 0% because of the low spring load and solenoid electrical load..

GFB diverter+, add a mechanical ''value'' to the setup. Which means, depending of the boost load, it will open/close under the solenoid and the system air pressure more precisely.

Let say you leave the gas and press if right after (quick shift), opening the DV at 100% will let the pressure system to go way to low than needed. But, DV+ can hold back and open i.e. 20%, and ready to take the turbo pressure back on quick shift.

= less lag, faster boost and throttle response.

( this is my understanding of the concept of this DV, you can correct me if needed)

That's pretty much it. It works regardless of the pressure either side of the piston, that's its main selling point.

I added my BSR CAI tonight, sounds even better :)

[shahk62]

Yep - that extra Spring is the money maker for the dv+. Means it shuts when there is no boost (normally the ecu would keep it open in this situation).

The BSR intake isn't bad once installed. But it's a case of get what you pay for haha


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[BenMTL]

Performance difference between this and the oem piston type? HP? Any trials/comparisons?

[oVeRdOsE]

Performance difference between this and the oem piston type? HP? Any trials/comparisons?

Can't tell.

I ride about 200km with stock tune/parts.

Then I did tune/exhaust/dv/intake/drop.

So yes huge difference, but can't tell if the DV made any difference. I believe so, at least on paper.

[shahk62]

Performance difference between this and the oem piston type? HP? Any trials/comparisons?

Hi Ben!
In terms of performance difference it won't yield any peak horsepower gain - but as boost is available earlier and is not lost during shifts you will see a response if you are dragging or during spirited driving.

So not necessarily higher hp but a solid DV solution which can hold boost up to 30psi, change from vaccum to boost much faster than oem.
If you wanted a graph there is one on the gfb website showing their "TMS" zone showing how boost pressures are improved in the low to mid end significantly.


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[pat_do]

Can't tell.

I ride about 200km with stock tune/parts.

Then I did tune/exhaust/dv/intake/drop.

So yes huge difference, but can't tell if the DV made any difference. I believe so, at least on paper.

Can you guys order that part?

[Charles.waite]

I think you've rise the point, but if I can add.

OEM diverter, if I'm not mistaken, got a bi-electric signal. 0V or xxV. Means that the solenoid is 100% load or 0%, means that the diverter should open 100% or close 0% because of the low spring load and solenoid electrical load..

GFB diverter+, add a mechanical ''value'' to the setup. Which means, depending of the boost load, it will open/close under the solenoid and the system air pressure more precisely.

Let say you leave the gas and press if right after (quick shift), opening the DV at 100% will let the pressure system to go way to low than needed. But, DV+ can hold back and open i.e. 20%, and ready to take the turbo pressure back on quick shift.

= less lag, faster boost and throttle response.

( this is my understanding of the concept of this DV, you can correct me if needed)

Thats not entirely correct. Diverter valves work by recirculating air between the turbo and the engine. if the DV doesn't open 100% then it won't relieve the pressure properly and it will cause the compressor wheel to stall or chop air. This actually slows the wheel down significantly. The electronic DV reacts much quicker than traditional manifold vacuum operated DVs and keeps our turbo as spooled up as possible by opening quickly and fully, letting the turbo shaft freewheel with as little resistance as possible thus keeping its speed up and when you get back on the throttle you'll ideally see very little time needed for the turbo to spool up again.

This does result in less lag and faster response. It can't result in any horsepower gain (unless your old valve was leaking so much the turbo wasn't able to boost to the proper psi).

But what you said, about the turbo "holding back boost" doesn't really make sense when you think about how the system works, what you're describing is more how the wastegate system functions...

[oVeRdOsE]

Thats not entirely correct. Diverter valves work by recirculating air between the turbo and the engine. if the DV doesn't open 100% then it won't relieve the pressure properly and it will cause the compressor wheel to stall or chop air. This actually slows the wheel down significantly. The electronic DV reacts much quicker than traditional manifold vacuum operated DVs and keeps our turbo as spooled up as possible by opening quickly and fully, letting the turbo shaft freewheel with as little resistance as possible thus keeping its speed up and when you get back on the throttle you'll ideally see very little time needed for the turbo to spool up again.

This does result in less lag and faster response. It can't result in any horsepower gain (unless your old valve was leaking so much the turbo wasn't able to boost to the proper psi).

But what you said, about the turbo "holding back boost" doesn't really make sense when you think about how the system works, what you're describing is more how the wastegate system functions...

That's why I spoke about solenoid signal.

By looking at the valve, I'm not quite sure if it's closing 100% or not, I'll go as per you said.

''holding back the pressure'' I mean between intake and turbo lines, I may not use the right terms, I'm trying to get it from my obervations. The diverter pipe is between atmospheric side and pressurized side. So if DV is 100% open, well, the air pressure that can be lost in that pipe size, in that time lap, will be ''lost''.
Having th GFB dv+ holding the opening, result somewhat like a orifice restraint plate (as we use in pump system, ie steam). At the end, The pressure lost in time between shift will be less.

Agreed with no hp gain, there's no way this DV can help to produce more energy.

[shahk62]

Agreed with no hp gain, there's no way this DV can help to produce more energy.

Just want to clarify- this would produce no extra peak hp. But would help with drag times.

[Charles.waite]

Just want to clarify- this would produce no extra peak hp. But would help with drag times.

Only if your current DV is leaking.

[quattro guy]

Ive had it for over a year already and its as flawless as it can be. I drive my car hard sometimes and no codes of any. My brother is about to tune his b7 tip with jhm, this is the dv he bought. I would recommend it. Like some say, you feel the car more responsive way sooner.

[Okedokey]

It can produce more power, as shown previously, if you reach and maintain boost more quickly and for longer, clearly, the shading under a graph would be greater, thus more overall power has been delivered into work. Peak power increase no, overall delivery over time, yes.

[Charles.waite]

It can produce more power, as shown previously, if you reach and maintain boost more quickly and for longer, clearly, the shading under a graph would be greater, thus more overall power has been delivered into work. Peak power increase no, overall delivery over time, yes.

And as I said, if your DV is leaking then yes you're right. I don't think the valve response is any different than a stock valve. It's probably less likely to leak though.

Simply putting in a DV that can hold higher boost won't give you any performance over a properly working stock valve.

Not a single person ever on the b6 forum would say a forge valve will offer more horsepower or even faster spool than a stock valve and nothing is different here. The DV+ is a great piece of kit, but it's not going to transform your car's performance in any way.

[j.gerbes]

And as I said, if your DV is leaking then yes you're right. I don't think the valve response is any different than a stock valve. It's probably less likely to leak though.

Simply putting in a DV that can hold higher boost won't give you any performance over a properly working stock valve.

Not a single person ever on the b6 forum would say a forge valve will offer more horsepower or even faster spool than a stock valve and nothing is different here. The DV+ is a great piece of kit, but it's not going to transform your car's performance in any way.

Have to disagree with you somewhat. I was super skeptical about this product (because of a review from a local tuner - which ended up to be a bogus attempt to sell me a BOV) and contacted GFB before installing it. GFB sent me slow-mo videos comparing the DV+ to the G and D revisions of the Pierburg DV.

The DV+ can close in half the time of the D and G. The videos also show the characteristic 'leaking' of the D, and how the G gets stuck half-open when there is over 5psi of pressure.

The DV+ can hold more boost than the stock valves, not that the D can't hold the max pressure that the K03 can produce (although it does leak somewhat). You're right in saying that it wouldn't necessarily transform your car's performance by holding more boost.

The way that the DV+ does transform your cars performance is with gear changes. The DV+'s design uses a secondary spring which closes the piston when there is *low* pressure, even when the solenoid of the original DV is open. This means that *some* pressure will remain built up, allowing for a smoother gear change.

I have a tiptronic auto. After installing the DV+ last Thursday, I have noticed a huge difference in gear change smoothness (particularly from 1st to 2nd). Down-changes are also more smooth, and the throttle responsiveness of the car has been noticeably (if not tremendously) improved.

Just my 2 cents. I am in no way affiliated to GFB, just a very happy customer.

[Nano909]

Just installed mine. You weren't kidding when you said it was a night and day difference. Money well spent. The turbo sound together with my turbo muffler delete and K&N intake sounds so sharp. Definitely worth it.

[dwinters14]

Ive this going on 2.5 years and not a single problem or thrown code.. Noticed a difference in holding psi between shift points over stock

this

[pezgoon]

Just installed mine. You weren't kidding when you said it was a night and day difference. Money well spent. The turbo sound together with my turbo muffler delete and K&N intake sounds so sharp. Definitely worth it.

this

Ps, we don't have a "turbo muffler" on the B7

That's a b8+ thing

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[dwinters14]

Ps, we don't have a "turbo muffler" on the B7

That's a b8+ thing

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Why the ??

I have noticed a significant change in how the car drives especially between gears. It's almost as if the car jumps when i shift because the boost pressure stays constant and doesn't have to build again. I have a great butt dyno and can feel even the littlest thing.

Next up for me is getting rid of my drivetrain slop which will make the car feel more direct.

[pezgoon]

Why the ??

I have noticed a significant change in how the car drives especially between gears. It's almost as if the car jumps when i shift because the boost pressure stays constant and doesn't have to build again. I have a great butt dyno and can feel even the littlest thing.

Next up for me is getting rid of my drivetrain slop which will make the car feel more direct.

Because you both responded to a thread that was 2 years old as if it were still active



There's a good chance those members aren't even active anymore, will never see the comments, and the same statement could've probably just been made in the "what did you do to your b7 today" thread

Oh and the turbo muffler statement, I Lol'd

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[pezgoon]

Just installed mine. You weren't kidding when you said it was a night and day difference. Money well spent. The turbo sound together with my turbo muffler delete and K&N intake sounds so sharp. Definitely worth it.

Why the ??

I have noticed a significant change in how the car drives especially between gears. It's almost as if the car jumps when i shift because the boost pressure stays constant and doesn't have to build again. I have a great butt dyno and can feel even the littlest thing.

Next up for me is getting rid of my drivetrain slop which will make the car feel more direct.

Just curious though, when you two upgraded did you go from rev A or rev D to the gfb Dv+??

I'm pretty sure my car has original revision (because everything else is original) and to me it doesn't seem like a lose boost during shifts which would also point to original revision (because it fully seals instead of leaking like rev D) so I'm just curious if I go to rev D if I will lose the way that the car drives and end up having to get the Dv+ instead of just wanting it lol


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