valvetronic experts anyone?

[Kizzu]

So I know this is a bit of a strange question but I would like some opinions on it.
has anyone disconnected the valvetronic wiring to ''limp mode'' so as to fully open the valvetronic?
the reason why I'm asking this is because as we all know the n53b30 has the same engine components as our n52 but with no valvetronic and a direct injection system. So if let's say someone tried this out would it harm the ngine at all? I heard that if you removed the wiring connected to the valvetronic the CEL won't light on but that's what I read for a N42 engine.

[Freon]

I would not try to outsmart the ECU's own limp modes or safety measures.

If there is an issue with the Valvetronic system and the ECU decides and was engineering to open Valvetronic and just use the throttle, it will do so on its own. People with internal engineering information have decided these fail-safe modes.

If your car is broken you need to fix it, not hack around the millions BMW engineered into the car. The short term fix is a tow truck and a rental car, not disconnecting things.

There's no way you "get rid of" a CEL by disconnecting wiring in your car, full stop. That's a horrible idea. You're at best trading one CEL for another. It will certainly pop a different CEL for having disconnected the circuit.

[Kizzu]

Originally Posted by Freon

I would not try to outsmart the ECU's own limp modes or safety measures.

If there is an issue with the Valvetronic system and the ECU decides and was engineering to open Valvetronic and just use the throttle, it will do so on its own. People with internal engineering information have decided these fail-safe modes.

If your car is broken you need to fix it, not hack around the millions BMW engineered into the car. The short term fix is a tow truck and a rental car, not disconnecting things.

There's no way you "get rid of" a CEL by disconnecting wiring in your car, full stop. That's a horrible idea. You're at best trading one CEL for another. It will certainly pop a different CEL for having disconnected the circuit.

my valvetronic is doing just fine don't worry about that
I started this thread as I thought (which is most probably the case) that if the valvetronic gets switched off or switched to full tilt, the engine would make more power.
That said, I once saw a N52B30 with valvetronic at full tilt but this build in particular had e36 ITB's and a motec ecu so it's a bit far off from stock but anyways you get the point

[Freon]

Motec ECU probably cannot drive the Valvetronic sysem is my guess. If that engine makes more power, it's the ITBs and possible countless other cylinder head changes, not the Valvetronic being locked open specifically. I'd even guess it is a mechanical device that locks the valvetronic open (or they welded the worm gear that drives it), not a disconnected wire.

I don't see why using Valvetronic would limit your power. A throttle plate has to draw a vacuum in the entire intake manifold, where as Valvetronic allow roughly full atmospheric pressure all the way to the back of the intake valve at all times.

The only trick would be if the factory tune for some reason does not go to full open on the Valvetronic, but I'm doubting it withholds lift, and if you can reprogram it anyway you can just tune that out rather than turn it off and lock it full open.

That's also possibly a different kind of wear pattern on the valvetrain. You may find certain parts of the cylinder head wear faster than designed. I wouldn't want to be the first to try this on my daily driver at least.

[Taskmaster]

I was going to try it myself, but please - you first. 9.9mm of lift at all times would be interesting.

[Kizzu]

Originally Posted by TheAxiom

I was going to try it myself, but please - you first. 9.9mm of lift at all times would be interesting.

I wouldn't dare doing it. I thought it was just an interesting thought to share and ask if anyone has done it.
We need a lab rat ASAP THOUGH

[JimD]

It is terribly inconsistent with "limp mode" to assume the engine will make more power. While BMW may not change the valve lift while in this mode, there are many other things they can do to limit power.

[Kizzu]

Originally Posted by JimD

It is terribly inconsistent with "limp mode" to assume the engine will make more power. While BMW may not change the valve lift while in this mode, there are many other things they can do to limit power.

By saying ''putting the valvetronic to limp mode'' I meant that the engine would do more power if the valvetronic is set on full tilt.

[TheSt|G]

This is a terrible idea.

[Kizzu]

Originally Posted by TheSt|G

This is a terrible idea.

Why is that?
Don't want to go against your word or prove it wrong but 300+ bhp with stock internals and M3 ITB's doesn't sound a bad idea.

[Kizzu]

http://www.1addicts.com/forums/showthread.php?p=9529112

[JimD]

Maybe you have to be of a different generation to fully understand why this is a bad idea. When I started driving, some cars still had points (I had one that did) and condensors. Tuneups started with changing them and moved quickly to plugs and sometimes wires. So I have probably been driving longer than some of you have been alive.

Anyway, in the old days, the way you got more lift and vales open longer was to get a bigger camshaft. It had more lift and duration. You knew the guys who had replaced theirs because their car would hardly idle. At low rpm, it made if anything less power than before. Only at wide open throttle and high rpm would the power go up. There were "full race cams" that were extreme examples. Idle might have to be set up to 1500-2000 rpm just so the car would idle. But at high rpm, they had a lot of power. There was a boat on the lake in my backyard yesterday that sounded like it had a full race cam. It was noisy as heck, would hardly idle, but when he opened it up, the rooster tail was huge (maybe 30 feet in the air!). I don't know how fast he was going but the jet skis couldn't keep up.

That's the kind of thing that would result by locking the bimmer to the maximum lift and duration. A car that won't idle, has no power off the line, and only runs well near redline. At at high rpm, it doesn't have more power than before, it has the same power as before.

Leaving valves open a lot at low rpm doesn't let the car breath as well as does reduced lift. That's why normal cars didn't get full race cams, in the old days. For race cars, and maybe cigarette boats, big cams may make sense. In bimmers, it's better to let the car have a lower lift lower duration cam at low rpm and progress to a big cam at high rpm. That provides maximum power across the rpm range.

[Iron Man]

Originally Posted by TheSt|G

This is a terrible idea.

+1000. This sounds like a really stupid idea (at least for a daily/street driven car). I think JimD explained it perfectly.

[Kizzu]

Originally Posted by JimD

Maybe you have to be of a different generation to fully understand why this is a bad idea. When I started driving, some cars still had points (I had one that did) and condensors. Tuneups started with changing them and moved quickly to plugs and sometimes wires. So I have probably been driving longer than some of you have been alive.

Anyway, in the old days, the way you got more lift and vales open longer was to get a bigger camshaft. It had more lift and duration. You knew the guys who had replaced theirs because their car would hardly idle. At low rpm, it made if anything less power than before. Only at wide open throttle and high rpm would the power go up. There were "full race cams" that were extreme examples. Idle might have to be set up to 1500-2000 rpm just so the car would idle. But at high rpm, they had a lot of power. There was a boat on the lake in my backyard yesterday that sounded like it had a full race cam. It was noisy as heck, would hardly idle, but when he opened it up, the rooster tail was huge (maybe 30 feet in the air!). I don't know how fast he was going but the jet skis couldn't keep up.

That's the kind of thing that would result by locking the bimmer to the maximum lift and duration. A car that won't idle, has no power off the line, and only runs well near redline. At at high rpm, it doesn't have more power than before, it has the same power as before.

Leaving valves open a lot at low rpm doesn't let the car breath as well as does reduced lift. That's why normal cars didn't get full race cams, in the old days. For race cars, and maybe cigarette boats, big cams may make sense. In bimmers, it's better to let the car have a lower lift lower duration cam at low rpm and progress to a big cam at high rpm. That provides maximum power across the rpm range.

Actually I am of a different generation and I mainly ask here on what I read, so I apologize if this thread is a complete waste of time or just a shitty one.
I am not used to hear people talk much around here about mods being done on their beamers. to give you an idea, here (where I live) there are no e82 135i's registered and the only 125i registered happens to be mine, so as you can see there is no way that I can achieve any knowledge from here and comments like '' this is a bad idea'' won't help either (no offence to who left so), so thanks for the info

[JimD]

Originally Posted by Kizzu

Actually I am of a different generation and I mainly ask here on what I read, so I apologize if this thread is a complete waste of time or just a shitty one.
I am not used to hear people talk much around here about mods being done on their beamers. to give you an idea, here (where I live) there are no e82 135i's registered and the only 125i registered happens to be mine, so as you can see there is no way that I can achieve any knowledge from here and comments like '' this is a bad idea'' won't help either (no offence to who left so), so thanks for the info

I guess I also forget not everybody was messing with cars in their teens.

[Kizzu]

Originally Posted by JimD

I guess I also forget not everybody was messing with cars in their teens.

I'm still 20 so I think I have a tad more years to learn

[TheSt|G]

Originally Posted by Kizzu

Why is that?
Don't want to go against your word or prove it wrong but 300+ bhp with stock internals and M3 ITB's doesn't sound a bad idea.

Because in no way is that car streetable or reliable.

It will have zero low end power and require frequent rebuilds. If you spend most of your time between 5500 and 8000rpm, and don't mind spending $10k every 5,000-10,000 miles, go for it.

[MarkkyyMan]

As others have stated this isn't a good idea.

Main points being:
-Power Band won't be smooth, like Stig stated the low end will be terrible.
-Cold starts will be harsher on the motor.
-The engines overall efficiency will decrease, more fuel will be used.

JimD makes great points.

[Taskmaster]

It will be fine - It's essentially a fixed camshaft setup. Your emissions may be slightly worse, and fuel economy may suffer - but your throttle response should be slightly better. Power wouldn't be worse, as overlap is controlled by the vanos system.

[TheSt|G]

Originally Posted by TheAxiom

It will be fine - It's essentially a fixed camshaft setup. Your emissions may be slightly worse, and fuel economy may suffer - but your throttle response should be slightly better. Power wouldn't be worse, as overlap is controlled by the vanos system.

Why would your throttle response be better? Valvetronic is closer to ITBs than our single intake butterfly valve is.

[Taskmaster]

Originally Posted by TheSt|G

Why would your throttle response be better? Valvetronic is closer to ITBs than our single intake butterfly valve is.

I considering partial throttle load with different lift requirements. I agree without you though, and I never considered that.

[kobeballer96]

Originally Posted by TheAxiom

I considering partial throttle load with different lift requirements. I agree without you though, and I never considered that.

Lol go for it. I have a extra n52 for ya. Guy is selling it for 600 dollars. These things are cheap.