[335i E92]

Morning all...

Has anyone got any experience or an opinions on Forge DV's for the 335i?

My 335i is running great after the new actuators / injectors / coils and plugs.

As it was running smooth and sounded well I decided it was time to get mike at Mike at DMS put the remap back on. For the first few days the car was electric, so much so that you really had line the car up straight before approaching the right pedal as power was delivered hard and fast so much so that the wheels would instantly light up in 2nd gear even if it was dry road surface and warmed up rubber.

However after the first couple of days the power dropped off, this literally happened over night and the shove back was now much reduced. The engine its self still feels ultra smooth and still so purrs like a kitten. Also when I’m giving it the beans and change up a cog from say 2nd to 3rd it feels like the turbo isn’t holding boost it feels laggy and much slower.

The guys at Darren Wood in Stockport plugged her in and there are no fault codes showing and they couldn't see an obvious boost leak / split pipe although they only had time to give a quick inspection. Given this and the fact the engine still feels & sounds strong I am suspecting this could be a problem with the OEM DV'S.

I wondering if the OEM DV's are shot, i think they are a diaphragm set up so maybe the additional boost has torn them slightly. If so is it normal for the car not to throw a code for this? Has anyone experienced similar issues with stock DV's and remap or upgraded to Forge DV's?

Would you all agree with my diagnosis? As I said the car is running really well other than the loss of boost.

Any suggestions would be appreciated.

[E92Fan]

Originally Posted by 335i E92

Morning all...

Has anyone got any experience or an opinions on Forge DV's for the 335i?

My 335i is running great after the new actuators / injectors / coils and plugs.

As it was running smooth and sounded well I decided it was time to get mike at Mike at DMS put the remap back on. For the first few days the car was electric, so much so that you really had line the car up straight before approaching the right pedal as power was delivered hard and fast so much so that the wheels would instantly light up in 2nd gear even if it was dry road surface and warmed up rubber.

However after the first couple of days the power dropped off, this literally happened over night and the shove back was now much reduced. The engine its self still feels ultra smooth and still so purrs like a kitten. Also when I’m giving it the beans and change up a cog from say 2nd to 3rd it feels like the turbo isn’t holding boost it feels laggy and much slower.

The guys at Darren Wood in Stockport plugged her in and there are no fault codes showing and they couldn't see an obvious boost leak / split pipe although they only had time to give a quick inspection. Given this and the fact the engine still feels & sounds strong I am suspecting this could be a problem with the OEM DV'S.

I wondering if the OEM DV's are shot, i think they are a diaphragm set up so maybe the additional boost has torn them slightly. If so is it normal for the car not to throw a code for this? Has anyone experienced similar issues with stock DV's and remap or upgraded to Forge DV's?

Would you all agree with my diagnosis? As I said the car is running really well other than the loss of boost.

Any suggestions would be appreciated.

The standard OEM DVs are plastic diaphragms and are anecdotally suitable for boost pressures up to around 11-12psi. The DMS remap will be pushing about 13.5-14psi boost and it is most likely the OEM DVs are starting to flutter as boost builds, therefore venting boost too early.

If the DV were to fail completely, you'd most likely get an underboost code eventually and the engine would go into limp mode. This would most commonly be seen if you're doing a long 3rd gear or 4th gear pull all the way to redline.

The Forge DVs are much more robust and have three stages/levels of tension in the diaphragm, interchangeable by swapping the supplied springs. You are best off getting a set of Forge DVs which are a direct swap, installing the middle tension of the three springs (I forget which colour) and using those in place of the OEM DVs.

You'll definitely be able to hold boost accurately and if there is still a lack of boost pressure and shove, then you know the problem lies elsewhere.

Are you using super unleaded? You'll need to be using a 97RON petrol as a minimum due to the advanced timing and increased boost. The drop off in power when using a regular 95RON petrol is much more evident now your engine is tuned. Other things to check are the air filter - is it old and clogged? That makes a bit of a difference.

Also you should think about ambient air temperatures and humidity - has it become warmer and more humid in the last few days? If so, that will affect the car's performance considerably, especially since it's tuned. That's why an upgraded intercooler is such a good modification - it doesn't necessarily add more power, although in most cases it does, but it helps to maintain the stability of a car's available performance.

If all these things are ok, then you need to start investigating potential boost leaks. They can be very hard to find so I suggest you strike up a really good relationship with your local technician!!!

[335i E92]

Originally Posted by E92Fan

The standard OEM DVs are plastic diaphragms and are anecdotally suitable for boost pressures up to around 11-12psi. The DMS remap will be pushing about 13.5-14psi boost and it is most likely the OEM DVs are starting to flutter as boost builds, therefore venting boost too early.

If the DV were to fail completely, you'd most likely get an underboost code eventually and the engine would go into limp mode. This would most commonly be seen if you're doing a long 3rd gear or 4th gear pull all the way to redline.

The Forge DVs are much more robust and have three stages/levels of tension in the diaphragm, interchangeable by swapping the supplied springs. You are best off getting a set of Forge DVs which are a direct swap, installing the middle tension of the three springs (I forget which colour) and using those in place of the OEM DVs.

You'll definitely be able to hold boost accurately and if there is still a lack of boost pressure and shove, then you know the problem lies elsewhere.

Are you using super unleaded? You'll need to be using a 97RON petrol as a minimum due to the advanced timing and increased boost. The drop off in power when using a regular 95RON petrol is much more evident now your engine is tuned. Other things to check are the air filter - is it old and clogged? That makes a bit of a difference.

Also you should think about ambient air temperatures and humidity - has it become warmer and more humid in the last few days? If so, that will affect the car's performance considerably, especially since it's tuned. That's why an upgraded intercooler is such a good modification - it doesn't necessarily add more power, although in most cases it does, but it helps to maintain the stability of a car's available performance.

If all these things are ok, then you need to start investigating potential boost leaks. They can be very hard to find so I suggest you strike up a really good relationship with your local technician!!!

Hi Tony

Thanks for the input, as usual informative, detailed and very much appreciated!!

In the 5 months I’ve owned the car it’s has drank nothing other than V- Power. Also the car had an oil change and new air filter only a few weeks ago so along with the new actuators / full set of injectors / full set of coils full set of plugs it’s had a major overhaul. This is why I’m certain this is a boost problem as the engine feels really strong.

You mentioned that if the diaphragms are damaged they will vent boost too early. I’m definitely experiencing this as the power has dropped of considerably at the top end of the rev range. And isn’t holding boost between spirited gear changes.

I definitely agree that our cars especially once mapped suffer when it’s warm and humid, unfortunately I can’t stretch to an intercooler at the mo as bridezilla is taking all my cash for our wedding next year!!

As for the Forge DV’s I’ve read up that they come with a green and a yellow spring. Apparently the green one is for stock set up and the yellow is for tuned.

Do you have updated DV’s on yours?? Are they ok with stock charge pipes as I’ve seen Stett do a charge pipe of the 335i? The only problem is I want to keep the engine bay looking stock. I know the forge DV’s come in chrome or black, I will be ordering the black because of this. It’s just a nightmare trying to explain to the INS Company what a Forge DV is so I’d rather keep it under radar!!

[E92Fan]

Originally Posted by 335i E92

Hi Tony

Thanks for the input, as usual informative, detailed and very much appreciated!!

In the 5 months I’ve owned the car it’s has drank nothing other than V- Power. Also the car had an oil change and new air filter only a few weeks ago so along with the new actuators / full set of injectors / full set of coils full set of plugs it’s had a major overhaul. This is why I’m certain this is a boost problem as the engine feels really strong.

You mentioned that if the diaphragms are damaged they will vent boost too early. I’m definitely experiencing this as the power has dropped of considerably at the top end of the rev range. And isn’t holding boost between spirited gear changes.

I definitely agree that our cars especially once mapped suffer when it’s warm and humid, unfortunately I can’t stretch to an intercooler at the mo as bridezilla is taking all my cash for our wedding next year!!

As for the Forge DV’s I’ve read up that they come with a green and a yellow spring. Apparently the green one is for stock set up and the yellow is for tuned.

Do you have updated DV’s on yours?? Are they ok with stock charge pipes as I’ve seen Stett do a charge pipe of the 335i? The only problem is I want to keep the engine bay looking stock. I know the forge DV’s come in chrome or black, I will be ordering the black because of this. It’s just a nightmare trying to explain to the INS Company what a Forge DV is so I’d rather keep it under radar!!

I've been running Forge DVs with the stock charge pipe for over two years. I have the chrome ones as the black ones weren't out then, and they fit perfectly. Took twenty minutes to install. Get the black coloured versions and no one will ever know the difference!

Try it and see how it goes - you might find that all the power at the top end comes back!

[335i E92]

Originally Posted by E92Fan

I've been running Forge DVs with the stock charge pipe for over two years. I have the chrome ones as the black ones weren't out then, and they fit perfectly. Took twenty minutes to install. Get the black coloured versions and no one will ever know the difference!

Try it and see how it goes - you might find that all the power at the top end comes back!

Black Forge DV's it is then. One last qustion!!

Where is the best place to order?? Is this somthing that Teddy at SSDD can suppy?

[E92Fan]

Originally Posted by 335i E92

Black Forge DV's it is then. One last qustion!!

Where is the best place to order?? Is this somthing that Teddy at SSDD can suppy?

Get it from Evolve or direct from Forge

www.evo-s.co.uk
www.forgemotorsport.co.uk

[335i E92]

Originally Posted by E92Fan

Get it from Evolve or direct from Forge

www.evo-s.co.uk
www.forgemotorsport.co.uk

Thanks agian Tony, Just placed order with Imran @ Evole

[doughboy]

God I love this forum.

Question asked, question answered, parts ordered. sorted. bloody great!

Best get mine ordered ready for the re-map!

[zltm089]

Sorry, but what does DV stand for? and is it compulsory to change them if you have your car remapped?

[335i E92]

Originally Posted by zltm089

Sorry, but what does DV stand for? and is it compulsory to change them if you have your car remapped?

DV stands for diverter valve, it holds the boost for the turbos!!

Doughboy, finaly taking the plunge for a remap. Ha ha good man!! One question evolve or dms??

As for it being compulsary for a remap, in my case yes as it seems the stock ones don't cope too well with the extra boost

[doughboy]

I'll be going to P-torque.

Just waiting till i get the suspension and brakes sorted next week, then i'll try and get it mapped before Silverstone track day in October.

[m1bjr]

Originally Posted by 335i E92

Morning all...
However after the first couple of days the power dropped off, this literally happened over night and the shove back was now much reduced. The engine its self still feels ultra smooth and still so purrs like a kitten.

Also when I’m giving it the beans and change up a cog from say 2nd to 3rd it feels like the turbo isn’t holding boost it feels laggy and much slower

Would you all agree with my diagnosis? As I said the car is running really well other than the loss of boost.

Any suggestions would be appreciated.

Okay, rather than get into the DV mindset, this also sounds a lot like the EMU yanking back the timing due to some det.
Now thats pretty easy to establish if you have a BT cable an laptop as you can graph the timing realtime.
As thats free to do that would have been my first test.
I'm running oem DVs at 50k miles old now, and about 14psi with no issue at all btw.

S.

[335i E92]

Originally Posted by m1bjr

Okay, rather than get into the DV mindset, this also sounds a lot like the EMU yanking back the timing due to some det.
Now thats pretty easy to establish if you have a BT cable an laptop as you can graph the timing realtime.
As thats free to do that would have been my first test.
I'm running oem DVs at 50k miles old now, and about 14psi with no issue at all btw.

S.

Hi

Unfortunatley don't have a bt cable, what is a emu, and how could it effect the power?? The engine sounds and feels smooth to me so if the timing and det was out it would surley feel & sound rough or off??

Along with all the new hardware the car has had I had the adaptations reset a couple of weeks ago which should have sorted any timing / detonation issues. Maybe I'm wrong, I'm no expert!!

Does everyone alse agree that this sounds like a boost leak or DV issue???

I wanted to get the Forge DV's anyway and they are being fitted on Thursday. If this doesn't fix it then plan is to get a smoke test done to further investigate the leak.

[doughboy]

m1bjr is right, get a BT (bavarian technic) cable and software - only £250 and it could save you that straight off.

Until you have some data to back it up you could just be changing parts and be chasing the fault round the houses.

[335i E92]

Originally Posted by doughboy

m1bjr is right, get a BT (bavarian technic) cable and software - only £250 and it could save you that straight off.

Until you have some data to back it up you could just be changing parts and be chasing the fault round the houses.

Hi

Even if i did have a BT cable i wouldn't know what to look for. As i said in the previous post i dont know what an EMU is or how it could effect DET or blah blah blah, means nothing to me. All i know is the car isn't throwing any codes and without a BT cable and the knowledge to extract the information from the car myself i have to just start with the most obvious!!

As i said even if it isn't the DV's i wanted to upgrade to the forge ones anyway as they help to hold boost after a remap and slightly reduce the lag. They are being fitted on Thursday. If this doesn't solve the problem then i'll get a boost leak smoke test done.

I'm hoping that the forge DV and boost leak test will expose the issue, if not i'll probably just have to wait for a code. With all the new hardware on the car and the fact that the engine itself sounds ultra smooth i'll be proper stumped if its not a boost leak or faulty DV

Will keep you all posted when they get fitted on Thursday

Does anyone know of a garage that does the boost leak smoke test in or around Manchester, or just a decent boost leak test?? Darren Woods dont do the smoke test!!

[335i E92]

On the other hand...


If anyone has a BT cable and the required skills to plug it in and gauge if there are any obvious issues with my 335i that might be causing the symptons it would be a major major help!!

I live in Bramhall South Manchester!!

[fastloop]

I got a pro BT cable, but I don't live anywhere near you and from my experience it will be tricky to figure out what's going on without the car throwing codes. Sure you can have a look at the actual values and see if something is massively off from what you would expect. However it really depends on what's causing this. If a hose had popped off I would expect it to throw codes, however a small leak may not. From what you describe it's sounds like it's only slightly down on power on higher boost, so it would be more likely to be in the area of the DVs than a loose FMIC coupling. Perhaps the DVs fluttering would be visible on a boost graph.

How big a drop in performance are we talking about?

[335i E92]

Originally Posted by 335rocks

I got a pro BT cable, but I don't live anywhere near you and from my experience it will be tricky to figure out what's going on without the car throwing codes. Sure you can have a look at the actual values and see if something is massively off from what you would expect. However it really depends on what's causing this. If a hose had popped off I would expect it to throw codes, however a small leak may not. From what you describe it's sounds like it's only slightly down on power on higher boost, so it would be more likely to be in the area of the DVs than a loose FMIC coupling. Perhaps the DVs fluttering would be visible on a boost graph.

How big a drop in performance are we talking about?

Hi,

Not a massive drop in performance, if for example I give it some in 2nd it will give a good boost (not as electric as it has been I'll still get a little wheel spin but the back end doesn't squirm about as it used to) it's when I then change up quicy to 3rd It just feels much less punchy like it's not held the boost from 2nd to 3rd and then same in 4th. So I guess the main problem is holding boost between changes and also it's lost some kick in the higher rev ranges, starting to fade past 4.5k in the rev range agian as though it's stughling to hold on to the boost. This is why I was thinkin it's more dv issue or as you say a small boost leak.

Would you agree?? Dv's are getting fitted on thurs so I'll see what difference it makes, from there I will get a boost leak test done if still no different

[fastloop]

Hard to say, a small drop in performance could be many things so we are still guessing a bit here. At least with the DVs on Thursday we'll be able to rule that out. Next step may be some monitoring with BT or similar to check timings etc. Perhaps ECU adaptation are softing the feel.

Is yours AT or MT?

[doughboy]

Originally Posted by 335i E92

On the other hand...


If anyone has a BT cable and the required skills to plug it in and gauge if there are any obvious issues with my 335i that might be causing the symptons it would be a major major help!!

I live in Bramhall South Manchester!!

Unless someone has the 'pro' cable with unlimited useage (£700) the regular cables are only for use on 3 cars and are locked out after use on 3 different chassis numbers, so it would be a 3rd of someones £250 use it on another car....

Its always nice to fit some nice billet alloy parts on any car, so just get the forge DVs anyway....

[335i E92]

Hi

Drove the car this morning and was behind a run of 3 cars doing about 40mph in a 60mph. Dropped it down to 3rd and gave it some right foot, it seemed to deliver the power very strangely, i had an initial kick then linier delivery then another little boost then fade out to the top of the rev range.

Is this the DV flutter that some of you have mentioned??

"335Rocks" yeah very much looking forward to the DV's being fitted on Thursday to see if they fix it and if not I’ll get the whole system checked for a boost leak. By the way i had this problem before the adaptations were reset so its not that.

"Doughboy" Thanks for the info, didn't realise you were restricted by chassis number on the BT cable.

Does anyone know if there is a garage that offers the boost leak smoke test in the Manchester area?? Or a reliable boost leak test if not smoke??

[Em135eye]

And Tony your subject is?

Tony: The BMW E90, 92 and 93