HYDE16 Poll - Long Term GFB T9351 DV+ Diverter Valve Kit Results

[vwgti2.0t]

So here are the results. I included 2 runs WITH the spring in the DV+. Like I said, I always had weird surging issues after clearing the codes, which you can see in the one run WITH the extra spring.

Granted, this is on a pretty big scale, so the difference between the peak boost you see is actually like .2 psi. Yes, I agree that the DV+ WITH the spring can hold SLIGHTLY better boost.. BUT, the boost curve with the stock valve is by far the smoothest, and although it's under the DV+ WITH the spring at some points, it's only by .2psi.

Like I said above, the car with the stock valve performs the smoothest out of all operational configurations. Also, since switching back to the stock valve my MAF flow reading have now increased back to around where I think they are supposed to be.

Also, I will say despite with the graph says I did feel the DV+ WITHOUT the spring did seem very smooth as well. But since without the spring is still making less boost than the stock valve, I'm not switching it.

I think I'll just be keeping the stock valve in.

EDIT: I just graphed the only other run I took this morning with the stock DV. I was doing pulls in 4th and I only made it to 5800 on the last run so I didn't include it on the graph below. BUT, the peak spike matches the highest peak below (the one with the DV+ WITH the extra spring), and boost stays very similar to to highest points on this graph. I wish I could've gotten a full run in to see what it did after 5800 rpm. Maybe I'll try and get some more data on the way home. I don't want to be too much of an asshole doing pulls from 2-6.5k in 4th on public roads, but I can't do it in third as I usually get a tad bit of wheelspin when full boost comes in.

 

[sean@apr]

Thanks for collecting the data! Hopefully this settles the DV debate once and for all; although I know it won't.

 

[jay745]

excellent info here

 

[TheCastle]

Manual or DSG = DSG
Turbo setup (IHI/K03, K04, BT) = K04
Software used (company and version/level) = APR K04 V3.1
Have you received a soft code with the main spring left in = NO
Data comparisons (can you share any before and after logs) = Yes, I have that data but not processed for pub. Basically I replaced my OEM diverter with a brand new diverter. Then added the DV+ shortly after replacing my diverter for dutabnility purposes. It made no measurable or precieved difference as compared to a brand new diverter valve.
Overall feedback and impressions = Good product, not a performance upgrade if your diverter is working.
Your current configuration (choose from the numbered options below) = 2

Bottom line to me was it made no difference, but I bought it and ran it for 10K miles and found it held up well.

 

[sterkrazzy]

Manual or DSG = Manual
Turbo setup (IHI/K03, K04, BT) = k03
Software used (company and version/level) = Apr Stage 2
Have you received a soft code with the main spring left in = n/a
Data comparisons (can you share any before and after logs) = n/a
Overall feedback and impressions = I think I must have had a bad dv (rev g) because I thought was pretty crazy how much it improved certain things, mostly smoother shifts. It's definitely one of my favorite mods.
Your current configuration (choose from the numbered options below) = 5

Only had it for a month or so now, but so far so good.

 

[krnboy817]

Manual or DSG = DSG
Turbo setup (IHI/K03, K04, BT) = k03
Software used (company and version/level) = STOCK
Have you received a soft code with the main spring left in = n/a

installed the dv + about 4 days ago now and have no issues. better throttle response and sensitivity. accel pedal is much "stiffer" than stock dv set up. boost comes on quick. steady max boost.

 

[McFuzz]

Manual or DSG = Manual
Turbo setup (IHI/K03, K04, BT) = IHI stock turbo
Software used (company and version/level) = APR Stage II 1.2
Have you received a soft code with the main spring left in = Is it P0088? If so - yes; but only once so far.
Data comparisons (can you share any before and after logs) = N/A
Overall feedback and impressions = Boost gauge indicating better boost response and an increase of about 1.5ish psi at peak (was 16.5-17ish, does 18 now with spike of 20).
Your current configuration (choose from the numbered options below) = 5



So - just had mine installed today; saw P0088 via the APR Mobile app but I am not sure if it was there before hand or whether this was a result of the the DV+. I've reset the code and we'll see if it pops up again.

 

[corrado917]

I've been considering to buy this product for the longest time :laugh: , so no biggie to read this over and over again. However, is it me or most of you guys agree on the half benefits of the DV+ at low RPM band ONLY? "Graph included" Nothing said about high RPM, guess there is none or close to the cheaper stock DV unit?

.....The boost pressure and turbo are fairly irrelevant as far as the main spring go. You could potentially say as a blanket rule to the guys with a DSG gearbox that they can install the DV+ without the spring, because throttle response on gearshift is much less important than it is to the manual guys........ [/I]

... With the spring I do feel better throttle response with no negatives besides the soft code...

...Overall feedback and impressions = I like the partial throttle response but I do get fluttery sounds...

....reinstalled it and immediately felt positive results between shifts. I'm a believer

..Overall feedback and impressions = Ever since I installed it, I feel as if it holds boost a bit longer in the rev range and completely got rid of the open intake howl at 3000-5000RPM in 3rd and 4th gear

...Overall feedback and impressions = I didn't feel much, but I know it's more reliable, so it's staying.

One thing to note, I ALWAYS had problems with going into sort of a soft limp mode after a really fast shift at high RPM where boost wouldn't build right back up. . .

Basically I replaced my OEM diverter with a brand new diverter. Then added the DV+ shortly after replacing my diverter for dutabnility purposes. It made no measurable or precieved difference as compared to a brand new diverter valve. [/B]
Overall feedback and impressions = Good product, not a performance upgrade if your diverter is working.

Overall feedback and impressions = I think I must have had a bad dv (rev g) because I thought was pretty crazy how much it improved certain things, mostly smoother shifts. It's definitely one of my favorite mods.
Your current configuration (choose from the numbered options below) = 5Only had it for a month or so now, but so far so good.

better throttle response and sensitivity. accel pedal is much "stiffer" than stock dv set up. boost comes on quick. steady max boost.

Note: I'm testing one soon & free, but with DSG & highway commute (little bit over the high end RPM band), my expectations are not that high to be honest.

 

[HYDE161]

So here are the results. I included 2 runs WITH the spring in the DV+. Like I said, I always had weird surging issues after clearing the codes, which you can see in the one run WITH the extra spring.

Granted, this is on a pretty big scale, so the difference between the peak boost you see is actually like .2 psi. Yes, I agree that the DV+ WITH the spring can hold SLIGHTLY better boost.. BUT, the boost curve with the stock valve is by far the smoothest, and although it's under the DV+ WITH the spring at some points, it's only by .2psi.

Like I said above, the car with the stock valve performs the smoothest out of all operational configurations. Also, since switching back to the stock valve my MAF flow reading have now increased back to around where I think they are supposed to be.

Also, I will say despite with the graph says I did feel the DV+ WITHOUT the spring did seem very smooth as well. But since without the spring is still making less boost than the stock valve, I'm not switching it.

I think I'll just be keeping the stock valve in.

EDIT: I just graphed the only other run I took this morning with the stock DV. I was doing pulls in 4th and I only made it to 5800 on the last run so I didn't include it on the graph below. BUT, the peak spike matches the highest peak below (the one with the DV+ WITH the extra spring), and boost stays very similar to to highest points on this graph. I wish I could've gotten a full run in to see what it did after 5800 rpm. Maybe I'll try and get some more data on the way home. I don't want to be too much of an asshole doing pulls from 2-6.5k in 4th on public roads, but I can't do it in third as I usually get a tad bit of wheelspin when full boost comes in.

Interesting response from GFB after they saw the data posted here...

If you were to take a couple of boost logs every day without changing anything mechanically, you’d see quite a variation in peak boost and boost stability. What a lot of people forget is that boost pressure is controlled by a wastegate, which is a mechanically variable part, AND which is controlled by forecasting the boost pressure. Since there is a time lag between the N75 duty cycle changing and the boost pressure responding, the ECU must PREDICT when boost pressure will peak and respond accordingly, same goes for when boost pressure will start to drop off, or changes caused by atmospheric pressure, temperature, what gear you are in, whether you floor the throttle at 2000RPM or 4000RPM, the boost rise rate etc etc.

For example, if you log the boost pressure and the N75 duty, you’ll see the N75 duty goes to about 95% during spool up, and some time before peak boost is reached the N75 duty drops to pre-empt the overshoot and the time it takes for the wastegate to react. If you wait until you hit the target boost before correcting the N75 duty, it will overshoot. It’s a lot like throwing a ball in the air to try to just touch the ceiling – you have to judge how hard to throw it, based on how far the ceiling is to begin with, and how heavy the ball is. It’s a lot harder when the height of the ceiling and the weight of the ball constantly change.

The ECU is very good at using historical data to predict boost pressure and react accordingly, however because of the large number of variables involved, it’s not perfect and no boost controller will EVER hold boost rock-solid ALL the time under ALL conditions. Where boost control becomes difficult is during fast-changing boost pressure, for example flooring the throttle above 3000RPM in a low gear. Boost rises to peak in less than a second, and in another second you’ll be nearing redline, where the engine’s airflow has doubled and the required N75 duty cycle is different than it was a second ago. Since the time lag in the boost control system can be up to 0.2-0.4 seconds, that’s a tall order controlling boost.

Therefore, it is INFINITELY more likely that small fluctuations in the boost pressure are caused by the boost control system, not intermittent leaks from a diverter valve (GFB or otherwise). A mechanical leak doesn’t know what RPM the engine is doing, it just sees pressure. It’s highly unlikely that it would blow open a little, then close, then open again, causing small fluctuations. If it’s going to blow open, it will just open.

A simple test we did on a dyno early on in DV+ development involved a remote-mounted diverter on a Golf R. We disconnected the recirc hose and plugged it, then connected another hose with a balloon on the end to the outlet of the diverter. Then we ran the car on the dyno. It sounds incredibly un-scientific, but the fact is you CANNOT be sure the diverter is leaking unless you measure the airflow from its outlet - data logging is NOT a 100% reliable indicator. It’s simple to see in this test that air does not leak out at random intervals or different RPM, and even in the case of the factory valve that was slightly leaking, it didn’t do it in any kind of fluctuating way, it just slowly inflated the balloon.

If the diverter is leaking, you’ll simply see a smooth change in boost pressure for a few runs, but the ECU will often correct it. After that, it becomes apparent in a change to the N75 duty cycle for the same boost pressure. It’s like the ball throwing example above - if the weight of the ball is increased without the thrower knowing, he’ll fall short the first few times.

Anyway, the easy way to illustrate this as I say is to take a larger sample without any mechanical changes. The problem is, boost pressure is typically only logged before and after a modification, or when troubleshooting. People don’t generally data log boost pressure on a daily basis, and if you did, you’ll definitely see a variation, simply because the wastegate isn’t some kind of magic device that provides a dead-accurate boost level 100% of the time.

 

[Cryptic19111]

^ Yup, that's a good explanation. Logging boost like that is always hard because of environmental variables.. same goes for dyno runs. I see people talking about comparing dyno numbers and all that, but unless you have the EXACT same conditions every time, the resulting numbers are going to vary. How many percent, I can't say, but I do know that you can dyno on the same machine 3 days in a row and have quite different numbers. They may be in the same general ballpark, but they are never 100% repeatable, so they are just a guide, and nothing to take as concrete fact. To me, it's more of a diagnostic tool to find out if you have a large boost leak, or something of that sort

outside temperature, humidity, barometric pressure, engine load percentage, incline of the road, heatsoak, etc all play a factor in what you'll see for readings. Yours are probably a bit more consistent because you have meth injection, but it all applies

 

[maskari_gti1]

Manual or DSG = DSG
Turbo setup (IHI/K03, K04, BT) = K04
Software used (company and version/level) = Unitronic Stage 2+
Have you received a soft code with the main spring left in = YES
Data comparisons (can you share any before and after logs) = NA
Overall feedback and impressions = To be honest, not much difference was noticed after the installation. But, it gives me some sort of peace of mind about holding boost and eliminate leaks from the OEM DV.

 

[hbrown0509]

Dead thread but did anyone notice any differences with the DSG and the GFB DV+ with the spring and without it?

 

[Jcarollo765]

Dead thread but did anyone notice any differences with the DSG and the GFB DV+ with the spring and without it?

I'll be taking out the spring on my K04 DSG.

 

[mto386]

I've switched it a few times, overall I like it out better. Seems smoother. I have a CTS K04 so experiences may vary.

 

[Jcarollo765]

I've switched it a few times, overall I like it out better. Seems smoother. I have a CTS K04 so experiences may vary.

I wouldn't trust this guy...super sketchy :bellyroll: