[hassmaschine]

picked up a waterpump/tstat for $220 on ebay. lol. I'm not that hopeful on the quality - but it's not like the $500 BMW pump is really any better..

I've been going through the TIS, tomorrow I'm going to try retarding the intake cam, and rotating the engine a few times (playing with the lift) and see if I can get anything to touch. I'm pretty sure it will work just fine!

[CobraMarty]

Try and see what limits the valvetronic. I don't think it is a 'hard stop'. I think it is the sensor that limits it's movement.

[Taskmaster]

Originally Posted by CobraMarty

Try and see what limits the valvetronic. I don't think it is a 'hard stop'. I think it is the sensor that limits it's movement.

The eccentric shaft? It's gear driven.

[justpete]

Originally Posted by CobraMarty

Try and see what limits the valvetronic. I don't think it is a 'hard stop'. I think it is the sensor that limits it's movement.

The Valvetronic cam can't increase lift beyond the limit of the rocker ratio and cam lobe dimensions. It's only a throttle mechanism and doesn't control the total available lift.

[hassmaschine]

Originally Posted by CobraMarty

Try and see what limits the valvetronic. I don't think it is a 'hard stop'. I think it is the sensor that limits it's movement.

Its a hard stop, and what pete said.

what the eccentric shaft is really doing is altering the rocker ratio. A lower ratio decreases how much the valves open, and a higher ratio increases it. At low lift the rocker ratio is close to zero, and at high lift the rocker ratio is about 1.35 by my math. You could potentially change the slope of the eccentric shaft cam to increase the ratio, but I think that would mess with how the DME calculates lift. The better way to do it would be to regrind the cam or get new cams with more lift. Then you can just change the parameters in the DME for what max lift should be and it will be happy (might be a little more work than that, but it's relatively simple).

[hassmaschine]

I can confirm - retarding the intake cam should work just fine.

Basically, you attach the fixture that holds the vanos units / timing wheels, & the fixture to hold the cams in position. Release the bolt that holds the vanos unit to the intake cam, remove the intake cam fixture, and rotate it clockwise.

I moved it 10 cam degrees (5 crank degrees). I have to do some thinking - I believe Vanos is measured in crank degrees, but I believe 10 crank degrees will work just fine.

I rotated the engine forwards and backwards several times (while holding the eccentric shaft at max lift) and there was not contact. I wouldn't expect there to be, since the retarded cam would open later, so issues of max lift at TDC don't exist. I also don't think it's possible with the stock cam for the intake and exhaust valves to touch.

I have to say, the ebay cam holding fixture is unsurprisingly poor quality. it's made well enough but the holes don't align with the head and the cam holding parts have too much play to give much confidence in them. It worked well enough for this, but I wouldn't recommend one if you want stock timing.

I'm going to try retarding it another 10 cam degrees (5 crank degrees) and see how that does. that would give us 60-130 degrees of cam adjustment - stock is 50-120 degrees. There is only one cell in the part throttle map that is advanced past 60 degrees so it really shouldn't affect anything other than now we could retard the intake cam another 10 degrees at high RPM.

It will have to be dealt with in the tune of course. You would have to subtract 10 degrees from every intake VANOS curve, except it couldn't go less than 50 degrees. Another alternative is to adjust the min/max settings, I'm not sure if that will work or not though - but then the VANOS maps would be actual cam degrees instead of having to remember that 120 degrees is really 130..

[justpete]

Originally Posted by hassmaschine

I can confirm - retarding the intake cam should work just fine.

Basically, you attach the fixture that holds the vanos units / timing wheels, & the fixture to hold the cams in position. Release the bolt that holds the vanos unit to the intake cam, remove the intake cam fixture, and rotate it clockwise.

I moved it 10 cam degrees (5 crank degrees). I have to do some thinking - I believe Vanos is measured in crank degrees, but I believe 10 crank degrees will work just fine.

I rotated the engine forwards and backwards several times (while holding the eccentric shaft at max lift) and there was not contact. I wouldn't expect there to be, since the retarded cam would open later, so issues of max lift at TDC don't exist. I also don't think it's possible with the stock cam for the intake and exhaust valves to touch.

I have to say, the ebay cam holding fixture is unsurprisingly poor quality. it's made well enough but the holes don't align with the head and the cam holding parts have too much play to give much confidence in them. It worked well enough for this, but I wouldn't recommend one if you want stock timing.

I'm going to try retarding it another 10 cam degrees (5 crank degrees) and see how that does. that would give us 60-130 degrees of cam adjustment - stock is 50-120 degrees. There is only one cell in the part throttle map that is advanced past 60 degrees so it really shouldn't affect anything other than now we could retard the intake cam another 10 degrees at high RPM.

It will have to be dealt with in the tune of course. You would have to subtract 10 degrees from every intake VANOS curve, except it couldn't go less than 50 degrees. Another alternative is to adjust the min/max settings, I'm not sure if that will work or not though - but then the VANOS maps would be actual cam degrees instead of having to remember that 120 degrees is really 130..

This is extraordinarily good news. Not entirely unexpected but great nonetheless. That's one unknown down, thanks!

[tetsuo111]

Strong work, hassmaschine

Keep it up!

[hassmaschine]

Yeah, the labor to retard the cam and tune it would probably be significantly less than new or reground cams plus the labor of swapping them - there are so many steps to take it all apart. To retard the cam all you'd really need is to pull the valve cover and attach the fixture, plus adjustments to the tune. You still have to tune for cams so it doesn't even count.

That said if they end up being available i will still do cams, its way easier outside the car and i have to take it apart anyway.

[justpete]

Originally Posted by hassmaschine

Yeah, the labor to retard the cam and tune it would probably be significantly less than new or reground cams plus the labor of swapping them - there are so many steps to take it all apart. To retard the cam all you'd really need is to pull the valve cover and attach the fixture, plus adjustments to the tune. You still have to tune for cams so it doesn't even count.

That said if they end up being available i will still do cams, its way easier outside the car and i have to take it apart anyway.

Now if there can be a solution to the OFH interference with the cylinder #1 trumpet. Maybe alternate angling them up and down with cyl#1 angled up?

[hassmaschine]

Im going to try some mock ups with cardboard tubes and a replica itg filter housing. I think it can be done with the thinner housing.

[justpete]

Originally Posted by hassmaschine

Im going to try some mock ups with cardboard tubes and a replica itg filter housing. I think it can be done with the thinner housing.

Cool. And we're all looking forward to the flow bench results for sure.

[hassmaschine]

yeah, trying to figure out if I want to buy another head to play with. there's a couple I've seen pretty cheap, one complete except the exhaust cam - would be good to have some extra parts, and it would give my head guy the opportunity to experiment a bit on the ports.

[CobraMarty]

If the Valvetronic hits a hard stop to limit max lift, does it look like the hard stop could be ground a bit so that there is more valve lift. IIRC stock is about 10mm, maybe be able to increase lift to 11.0-11.5mm valve lift.

Increasing valve lift will lead to more power than retarding the cams.

[justpete]

Originally Posted by CobraMarty

If the Valvetronic hits a hard stop to limit max lift, does it look like the hard stop could be ground a bit so that there is more valve lift. IIRC stock is about 10mm, maybe be able to increase lift to 11.0-11.5mm valve lift.

Increasing valve lift will lead to more power than retarding the cams.

You can't get any more lift than the cams can provide and this number is where the Valvetronic quits, simple as that. Power is produced by retarding the cams at higher revs, that's a fact. Lift helps but rate and duration matter as well but the DME has to know these parameters to function correctly. Valve diameter can also matter if it's the flow limiting parameter. Personally I'm looking to go beyond this to custom pistons and higher CR with cams to match, etc.

[hassmaschine]

Originally Posted by CobraMarty

If the Valvetronic hits a hard stop to limit max lift, does it look like the hard stop could be ground a bit so that there is more valve lift. IIRC stock is about 10mm, maybe be able to increase lift to 11.0-11.5mm valve lift.

Increasing valve lift will lead to more power than retarding the cams.

You can't possibly know that for sure without flow data. Generally more lift increases flow, but it often tapers off. We don't have any idea what the characteristics of the intake port flow are.

Also, retarding the cam is easy and requires no modification. We know it makes power because that is what vanos does. No, you can't grind the stop for more lift.. Good grief.

[CobraMarty]

Then can the computer be adjusted to give/allow more lift at WOT? I thought that there was a guy in Germany that was able to tune the ecu to do just that. Add 0.5-1.0mm more valve lift at WOT.

[justpete]

Originally Posted by CobraMarty

Then can the computer be adjusted to give/allow more lift at WOT? I thought that there was a guy in Germany that was able to tune the ecu to do just that. Add 0.5-1.0mm more valve lift at WOT.

Dude, the cam limits the lift, not the Valvetronic travel. There isn't anything you can do with the Valvetronic system to increase lift. Period. You can command more lift but it won't happen cuz, again, the cam limits lift, not the Valvetronic system.

[hassmaschine]

Originally Posted by CobraMarty

Then can the computer be adjusted to give/allow more lift at WOT? I thought that there was a guy in Germany that was able to tune the ecu to do just that. Add 0.5-1.0mm more valve lift at WOT.

no. you can change it from the stock tune (9.7mm) to 10mm but that's it. it's a mechanical limit. the only way to increase it is with a different cam - any "tuner" who says otherwise is a scammer.

speaking of scammers - perusing ebay for cheap deals on random parts. found a few things I needed, but man, there are sooo many scams. how about a used aluminum bolt set for the n52? good used parts! buy it now for $100! Oh boy, what a deal! Or a used waterpump with 100k miles for $300! wow, shut up and take my money! Then there are blocks and bed plates being sold as seperate parts (again, scrap when they are seperated), rockers sold as unmatched, mixed up sets (more junk - they have to be matched to the eccentric shaft, per cylinder). Geeze, I hope people aren't buying this crap!

[Taskmaster]

Originally Posted by hassmaschine

no. you can change it from the stock tune (9.7mm) to 10mm but that's it. it's a mechanical limit. the only way to increase it is with a different cam - any "tuner" who says otherwise is a scammer.

speaking of scammers - perusing ebay for cheap deals on random parts. found a few things I needed, but man, there are sooo many scams. how about a used aluminum bolt set for the n52? good used parts! buy it now for $100! Oh boy, what a deal! Or a used waterpump with 100k miles for $300! wow, shut up and take my money! Then there are blocks and bed plates being sold as seperate parts (again, scrap when they are seperated), rockers sold as unmatched, mixed up sets (more junk - they have to be matched to the eccentric shaft, per cylinder). Geeze, I hope people aren't buying this crap!

Report them!

[justpete]

Originally Posted by hassmaschine

no. you can change it from the stock tune (9.7mm) to 10mm but that's it. it's a mechanical limit. the only way to increase it is with a different cam - any "tuner" who says otherwise is a scammer.

I'm guessing that 3% increase in lift is negligible though.

[hassmaschine]

yeah it makes pretty much no difference.

actually, at some points you're better off with less lift as the increase in velocity increases VE. that has to be tested on a dyno though..