[CobraMarty]

Originally Posted by Noir

I doubt they could tell if you had them installed

One guy called me and thought I sent him some stock parts. He sent me a picture and I pointed out the changes. He was looking at the 'ramps'.
I do not change the 'ramps'. That is a complicated 3D shape.
I change the 'position' of the supports which change the geometry of the lift ratio.

They are like adding 1.6:1 roller rocker arms in a Chevy small block instead of the stock 1.5:1 rocker arms.

Downside?

They add just over +1mm to the intake valve lift. That is maximum lift. And only to the intake valve. This additional lift occurs when the piston is near BDC (bottom dead center) so no piston interference will occur. They only add the additional lift at over 80% eccentric cam position which is about 80% throttle to WOT.

So if you 'never' go over 80% throttle, you will never experience the additional lift. Because of the way that the Valvetronic mechanism works, there will be no additional 'anything'.

Now at baseline, like idle, the hydraulic lifter will be slightly more compressed, less than 0.010" more. This is well within the range for the hydraulic lifter.

Over 80% throttle, they will also add 2-3* of duration to the cam lift cycle. More lift and more duration equals 'more area under the curve' for the intake valve opening profile. More air is 'ingested' into the engine.
Variable lift and variable duration, below and above 80% throttle position

Only downside is 'you should have done it sooner'!

[hassmaschine]

Originally Posted by gunnerxq

Do you still have your track purposed e90?

You must be thinking of somebody else - maybe Pete?

Sadly, I haven't been to the track in quite some time. Just the reality of having small children.

[Xencer]

I just installed my set of MILVs yesterday, unfortunately I do have an auto car which I would like to swap to a manual, but with that being said I didn't feel much of a difference at all. Waiting for my tune to be emailed back to me to flash the car and I'm sure it will make a significant change there.

[hassmaschine]

yeah it's been said before, it's not going to do anything without a tune to set up the valve lift profiles.

[atmosphericM]

Originally Posted by Noir

I doubt they could tell if you had them installed

You're probably right, but eh.. I've got plenty of other mods to do in the meantime (suspension mainly), so I think I'm going to work on that stuff while my warranty slowly expires lol. And though the MILVs are pretty discrete alone, I plan on doing headers, tune, and probably MILVs all at once.. after the warranty expires. I know that they can't really deny me warranty service unless they can prove that my mods caused the issues, but shrug.. I'm old now so I'm playing it safe. I mean it's not like I'm ballin' enough to throw 5 grand at the car all at once anyway, so for now other mods will be the "chosen ones" lol.

[atmosphericM]

Originally Posted by Xencer

I just installed my set of MILVs yesterday,but I didn't feel much of a difference at all. Waiting for my tune to be emailed back to me to flash the car and I'm sure it will make a significant change there.

Originally Posted by hassmaschine

yeah it's been said before, it's not going to do anything without a tune to set up the valve lift profiles.

So just to 'dumb it down' for those of us that don't have experience writing ECU software ... Are you basically saying that, because more air is inherently and passively introduced into the combustion chamber (however according to Marty, ONLY near WOT), one needs a tune so that the ECU knows to send more fuel in there to take advantage of said increased O2? And I am guessing that this is because our "MAF Sensor" isn't really a MAF Sensor (think I read that here), so without the tune, the car doesn't know about the additional air?

[atmosphericM]

Originally Posted by CobraMarty

They add just over +1mm to the intake valve lift. That is maximum lift. And only to the intake valve. This additional lift occurs when the piston is near BDC (bottom dead center) so no piston interference will occur. They only add the additional lift at over 80% eccentric cam position which is about 80% throttle to WOT.

So if you 'never' go over 80% throttle, you will never experience the additional lift. Because of the way that the Valvetronic mechanism works, there will be no additional 'anything'.

They will also add 2-3* of duration to the cam lift cycle. More lift and more duration equals 'more area under the curve' for the intake valve opening profile. More air is 'ingested' into the engine.

So do they only add the 2-3* of duration AFTER the 80% threshold as a result of the +1mm lift change?

Really feeling like I should just check out that other thread at this point lol.

[Phyrexia]

As I understand it, the MILVs have been modified such that the physical Valvetronic mechanism provides more lift and more duration at >= 80%, and such that there is no change at all below 80%.

So you need to add more fuel to account for the increased airflow. Spark timing might be changed because of the changes to lift, I dunno.

Seems like a gimme. It's on my list.

[hassmaschine]

The MAF sensor is really a MAF sensor. The N52 can run without it, but on models with it, the sensor is used like normal.

The reason is because the load calcs (which are the basis of everything) are based on a model of intake valve lift. Since the DME "knows" how much the valves are open based on the model, it adjusts things like fuel, torque, etc. automatically. But when you change the valve lift (without updating the model), now the model is off and the DME's assumptions are wrong.

This isn't about adding fuel - the N52 uses wideband sensors that always run in closed loop (even at WOT). It will always follow the lambda target maps - there's no such thing as a 'base fuel' table. If you add more air it will always add more fuel but there are other things at play that make it not work out that simply.

[Xencer]

BTW, I used my digital Snapon torque wrench to break loose the bolts and the shouldered bolt for the springs are torqued at 10 Nm and the bolts for the block supports are 13 Nm. The install isn't hard, slightly time consuming but getting the valve cover off and back on is more difficult.

[atmosphericM]

A bit off topic I suppose but what exactly does the MAF sensor do in these cars, then? Is it more of just an "error check?" I was always under the impression that the MAF sensor measured the air going into an engine, and then the ECU added fuel based upon such. That said, it's starting to appear to me that, obviously, different cars work in different ways.

Thank goodness we have hassmaschine around here.

[hassmaschine]

the N52 DME has a couple algorithms it can use for measuring load and air density. One of them is with a MAF. The other is model based (actually, both of them use the model to some degree - but one has the MAF I guess as a sanity check).

Either way, the O2 feedback is much more heavily weighted than it would have been in the past, because they are widebands and the feedback loop is very fast and sensitive. So it doesn't really need the MAF, although it can use it. My belief is it's primarily for emissions reasons. I deleted mine a year ago and IMO it runs better that way. And many Euro cars came without them from the factory.

Actually, there's a third algorithm - the "Alpha-N" mode, but I'm not sure that was ever meant to run the engine long-term, and even in limp mode it's not used unless a specific variable is set (that is turned off from the factory). It's more of a failsafe, or maybe it was experimental, but AFAIK no factory tunes use it for anything. The method for the MAF delete I'm using doesn't use the "Alpha-N" table at all.

I'm not sure which mode the "Alpha-N" tune from BPC is using - but I doubt it runs in open loop unless it's using this 3rd mode, because the N52 never runs in open loop, not even in cold start (except maybe the first couple seconds).

[Phyrexia]

I didn't realize E90 lambdas were wideband. Fancy!

[hassmaschine]

BMW switched to widebands starting with the later E46 330i which runs MS45.1.

[Xencer]

Flashed the BPC MILVs tune earlier today and started driving in sport mode around tonight, had a short encounter with my buddy in a n54 e90 and he had a tougher time trying to pass me, haha. The torque increase is impressive, I didn't feel much at first but the speedometer will show you that you're moving much faster at low rpm.

[CobraMarty]

A PM conversation-

Hi Marty,
Following the milvs threads since day 1. Have a question on machining accuracy of the mod. Not searching by any means what exactly do you do to the stock part, just curious if you measure several units at the point you machine them, what kind of variation are you getting in thousands of an inch?
Thanks

Originally Posted by CobraMarty

My machinist is OCD anal. I say that in the highest complimenting respectful way.

Every single piece is measured.
They are all machined exactly the same.

Part of the accuracy is BMW themselves. The pieces are 'die cast' of quality metal. Every piece is exactly the same from BMW. Zero tolerance difference. All 10+ million that I estimate that they have made.

My machinist tolerances are less than 0.001", less than a thousandth of an inch.

Interesting is that the 'used' supports that I give him to machine are slightly 'harder' than the new parts. He has to set the mill slightly different for the 'used' parts.

The machining is very different than machining aluminum.
In my machinist words 'you have to have been doing this a long time to know the details in how to machine the part correctly and accurately'.

And to think that I thought I would buy a $2000 home mill and machine them myself. Thank goodness I found my machinist.
I would not make the MILVs available without him.

5 areas are machined and the oil 'groove' has to be machined.

I hope that helps,

Marty

[Xencer]

I have to say Marty, props to you for the insight. Car sounds much meaner as well.

[W37V]

Originally Posted by Xencer

Flashed the BPC MILVs tune earlier today and started driving in sport mode around tonight, had a short encounter with my buddy in a n54 e90 and he had a tougher time trying to pass me, haha. The torque increase is impressive, I didn't feel much at first but the speedometer will show you that you're moving much faster at low rpm.

Yeah, without tune, the mod is pointless. Give it about 100 miles for full adjustment. That tq is addicting.

[W37V]

Originally Posted by atmosphericM

So just to play devil's advocate.. What would/could be the potential downside(s) of this mod? I'm not saying the MILVs aren't worth it. In fact I'd be all over these if I was out of warranty. But typically mods have some sort of downside, albeit small, associated with them. [i.e. exhaust - increased noise; intake - dirtier filters, hydrolock; suspension - harsher ride; etc.] I've never installed aftermarket camshafts, either, so I don't know what their downsides are (increased fuel consumption?). Increased valvetrain wear? Anything at all? Just curious as surely BMW would have done it themselves if it was 110% kosher. Figured I might as well be that guy.

The only downside that I have noticed so far is smellier exhaust. I only have rear cats. On idle it seems like the exhaust is stinker than before.

I am not the only one who noticed this with their car. At least one other person reported similar experience with their car after the install.

[CobraMarty]

Is that 'smellier exhaust' due to the MILVs or the Tune? More fuel, more smell?

Not that it really matters as they go hand in hand.

[E91Swagger]

Thanks for the review w37, is your car 6mt?

[Noir]

Originally Posted by W37V

The only downside that I have noticed so far is smellier exhaust. I only have rear cats. On idle it seems like the exhaust is stinker than before.

I am not the only one who noticed this with their car. At least one other person reported similar experience with their car after the install.

F it!