[mrnuke]

Originally Posted by hassmaschine

That's done because of increased intake/exhaust valve overlap. We don't have that problem because we have VANOS.

It won't idle properly because the DME needs to be able to reduce lift down to 0.01mm - if suddenly minimum lift is 0.03mm, things are going to go wrong.

So therein lies the problem as it would be "easier" to lock valvetronic wide open and code it out for a set of custom cam's rather than calculate lift ratios, duration and everything and then do it within the DME to see it as "acceptable" ranges

[Taskmaster]

Originally Posted by hassmaschine

Fixed that for you - I don't want to confuse people

'ITBs' won't do anything for the N52 - the only reason to have throttles at all is a backup in case of valvetronic failure. Otherwise, you could just bolt tuned velocity stacks to the head, which is really why ITBs gain power.

That was my original plan, but I'm not comfortable with a lack of backup. In the case of an eccentric shaft failure, the valvetronic motor moves to a fixed point (by default, it's maximum lift). You could reduce that to a lower fixed position but you'd still have basically no throttle control... that wouldn't be good if you were on a track or a long road trip.

Tune it to cut the throttle on left foot braking.

[hassmaschine]

Originally Posted by mrnuke

I know this is only a minor thing, but wouldn't you be able to wire an ignition kill switch of some sort if it became a runaway? It would suck to have to trailer/flatbed it somewhere, but that would prohibit the "backup" system from having a total failure.

I guess but then what? you're going to just shut it off in the middle of the freeway? It would be better at least to change the limp mode lift target to something like ~1500rpm, but still not fantastic.

Originally Posted by mrnuke

So therein lies the problem as it would be "easier" to lock valvetronic wide open and code it out for a set of custom cam's rather than calculate lift ratios, duration and everything and then do it within the DME to see it as "acceptable" ranges

You would have to machine the head to fit N54/N53 intake cam trays. You can "lock" the VVT at full-lift by simply unplugging the eccentric shaft sensor, however you'd still have all the rocker ratios etc to deal with.

Originally Posted by Taskmaster

Tune it to cut the throttle on left foot braking.

That's not a bad idea, but that's not something you can just "tune" - it would take program mods, which for a safety feature I wouldn't personally be comfortable doing on anyone else's car but my own.

Another thing to point out is to simply delete the throttle takes effort. There are a lot of safety features programmed into electronic throttle control, and most of it is hard coded. I tried removing the throttle control on MSS54 a few years ago and it was basically impossible without re-writing the whole program. You could just leave the stock throttle laying in the engine bay I suppose but that's kind of a waste of weight and space.

[atmosphericM]

What about a custom CF airbox, around the velocity stacks, with the throttle body mounted at it's intake orifice?

[justpete]

Originally Posted by Taskmaster

Tune it to cut the throttle on left foot braking.

nononono, that would defeat the whole point of left foot braking, that is keeping the revs up while slowing just as needed.

[hassmaschine]

Originally Posted by justpete

nononono, that would defeat the whole point of left foot braking, that is keeping the revs up while slowing just as needed.

it would have to be activated only when "limp mode" is active.

Yeah, it's feasible but I'm not going to do it - too much code hacking even for me.

[CobraMarty]

If you had a custom ground intake cam done with more lift and same base circle, that might work. That would have to be a new billet rod then machined. $$$$ then the install.

The exhaust flows pretty well. BPC got about 500HP out of their turbo N52 and it all flowed out the exhaust just fine. I doubt you will have any gains with additional exhaust lift or duration. Unless maybe more air with FI or nitrous.
I've done computer sims with only varying the exhaust cam specs, lift and duration, and there was very little power to be gained when N/A.

These engines are well tuned even stock.
230hp is 1.26HP/CID and 300hp is 1.64HP/CID. These are very good numbers.

If you study the valvetronic mechanism there is very little to make it better. Can't rotate the ECC any more, maybe a new ECC with slightly more 'lift' on the cam but there is a limit which is less than the MILVs, more lift on the intake cam but you need to have the stock base circle for it to idle so not a regrind but a new billet cam is needed.
There is not much more to be gained. If you want more power, port the head, use MILVs, N54 intake and headers. And while the head is off add 0.5 to the compression.

[mrnuke]

Originally Posted by CobraMarty

If you had a custom ground intake cam done with more lift and same base circle, that might work. That would have to be a new billet rod then machined. $$$$ then the install.

The exhaust flows pretty well. BPC got about 500HP out of their turbo N52 and it all flowed out the exhaust just fine. I doubt you will have any gains with additional exhaust lift or duration. Unless maybe more air with FI or nitrous.
I've done computer sims with only varying the exhaust cam specs, lift and duration, and there was very little power to be gained when N/A.

These engines are well tuned even stock.
230hp is 1.26HP/CID and 300hp is 1.64HP/CID. These are very good numbers.

If you study the valvetronic mechanism there is very little to make it better. Can't rotate the ECC any more, maybe a new ECC with slightly more 'lift' on the cam but there is a limit which is less than the MILVs, more lift on the intake cam but you need to have the stock base circle for it to idle so not a regrind but a new billet cam is needed.
There is not much more to be gained. If you want more power, port the head, use MILVs, N54 intake and headers. And while the head is off add 0.5 to the compression.

Great info Marty! Just curious, but what software do you use to run said simulations?

[CobraMarty]

Desktop Dyno.
It is fun to play with.

I had another one that I can't remember.