Converting N55 style tuning to an N54?

Itsbrokeagain

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Had a random thought on the way home from work today.

Since it seems that single turbo guys suffer from killing pre-cat (well in this case, pre-turbo) 02 sensors, what kinda leg work would be needed to say, move over to a single bank setup like an N55? Eliminate one whole bank of 02 sensors, can stick the 02 behind the turbo where they'd live longer.

I was out of the dealer by the time the N55 was introduced, and I dont really mess with them all that much, but do they still have bank to bank control like the N54? If so, how is it accomplished now that only one pre-cat 02 reads for the entire engine?

I think the best of both worlds, a MAP based engine management system combined with the single bank of 02 tuning would allow someone with a ST to get much farther than dealing with the factory 02s failing frequently or having to purchase expensive ADV sensors.

Thoughts?
 

doublespaces

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There has been some work on this, I'm not sure where that has gone. The pre-turbo placement isn't so bad, pretty much all manifolds so it now and with the insulators being built in, failures are low or non-existent on properly designed kits.
 
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LamboLover

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A few have tested disabling MAF on MEVD17. Other advantages are load that goes to 327%, pressure scaling to 5 bar without any scaling problems. MEVD17 can also do realtime tuning which would be difficult on MSD8x which is also virtually out of calibration space stock. Problems might be solenoid injectors that flow less, valvetronic. Presumably engine wiring loom is different and other sensor and actuator differences we've not thought of. This is assuming you are meaning using MEVD17.2 to control an N54 in its original chassis. Maybe you meant something else.
 
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[email protected]

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Nov 14, 2016
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A few have tested disabling MAF on MEVD17. Other advantages are load that goes to 327%, pressure scaling to 5 bar without any scaling problems. MEVD17 can also do realtime tuning which would be difficult on MSD8x which is also virtually out of calibration space stock. Problems might be solenoid injectors that flow less, valvetronic. Presumably engine wiring loom is different and other sensor and actuator differences we've not thought of. This is assuming you are meaning using MEVD17.2 to control an N54 in its original chassis. Maybe you meant something else.

The N54 technically already has public tables and knowledge of the RPM x Boost Setpoint method of boost control.
The "standard" for boost control in stock maps, and some ots maps is MAF x Setpoint.

This is useful in situations where you are tuning for instance a single turbo, you're able to define the WGDC by the RPM and requested boost setpoint. You can adjust everything to down to a "T". The end result is very nice makes a perfectly smooth and stable boost control method.

For instance @Jeffman used this method for testing his spool strategies that even on stock turbos achieved peak boost pretty quickly comparatively. He mentioned gains of skipping 1k RPM on high boost spool rates.
 

doublespaces

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A few have tested disabling MAF on MEVD17. Other advantages are load that goes to 327%, pressure scaling to 5 bar without any scaling problems. MEVD17 can also do realtime tuning which would be difficult on MSD8x which is also virtually out of calibration space stock. Problems might be solenoid injectors that flow less, valvetronic. Presumably engine wiring loom is different and other sensor and actuator differences we've not thought of. This is assuming you are meaning using MEVD17.2 to control an N54 in its original chassis. Maybe you meant something else.

I did not perceive the question this way however I find this much more thought provoking. I always like the mevd17 more for these reasons.
 

Sbrach

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Someone, maybe Justin at Twisted, was speculating on running an N55 head on an N54 block. If it does in fact line up, even with a custom headgasket, that would be pretty interesting. Forged crank and proven closed deck / sleeve solutions + better flowing valvetronic head, more reliable solenoid injectors, and arguably a better DME.
 

doublespaces

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Someone, maybe Justin at Twisted, was speculating on running an N55 head on an N54 block. If it does in fact line up, even with a custom headgasket, that would be pretty interesting. Forged crank and proven closed deck / sleeve solutions + better flowing valvetronic head, more reliable solenoid injectors, and arguably a better DME.

Here is one of the better pieces on this matter:

My question is, what is the first step? I would like to see this conversation find some sort of conclusion.
 

jyamona

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Nov 7, 2016
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A few have tested disabling MAF on MEVD17. Other advantages are load that goes to 327%, pressure scaling to 5 bar without any scaling problems. MEVD17 can also do realtime tuning which would be difficult on MSD8x which is also virtually out of calibration space stock. Problems might be solenoid injectors that flow less, valvetronic. Presumably engine wiring loom is different and other sensor and actuator differences we've not thought of. This is assuming you are meaning using MEVD17.2 to control an N54 in its original chassis. Maybe you meant something else.

I believe he meant getting MSD8x to run as single bank, which is not technically possible as the number of banks is baked into the code via a compiler constant.

However, that's not to say it isn't possible to have both the lambdas in the downpipe, as we discussed before :)
 

Twisted Tuning

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Someone, maybe Justin at Twisted, was speculating on running an N55 head on an N54 block. If it does in fact line up, even with a custom headgasket, that would be pretty interesting. Forged crank and proven closed deck / sleeve solutions + better flowing valvetronic head, more reliable solenoid injectors, and arguably a better DME.


I remember talking about it. It was mainly due to someone asking if it could work. I was just letting them know, that if someone wanted to they could mate it up to the N54 block. But at the cost, it may not be worth it since you can get the same flow with a head job. And you still need to worry about controlling the valvetronic, unless you were talking about putting an N54 block in the N55 car. But the valvetronic is the one of the biggest benefits of the N55 despite some people saying they hate it.

But then, why bother? M2 crank is forged, direct swap. the only difference between the strength of the N54 and N55 is the crank being forged in the N54 and the crank being cast in the N55 (non M). And we have yet to see a failure from power destroying a crank in the N55. The pistons and rods between the two are pretty much the same. with the N55 theoretically having the better rod design on paper.
 

Sbrach

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Yeah M2 crank and forged rods would be a better upgrade to an N55 but an N54 short block could be a good upgrade if the head gasket wasn't expensive to have made custom.
 
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doublespaces

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I remember talking about it. It was mainly due to someone asking if it could work. I was just letting them know, that if someone wanted to they could mate it up to the N54 block. But at the cost, it may not be worth it since you can get the same flow with a head job. And you still need to worry about controlling the valvetronic, unless you were talking about putting an N54 block in the N55 car. But the valvetronic is the one of the biggest benefits of the N55 despite some people saying they hate it.

So, what would need brought over to control the valvetronic besides the DME and the head obviously?

Yeah M2 crank and forged rods would be a better upgrade to an N55 but an N54 short block could be a good upgrade if the head gasket wasn't expensive to have made custom.

What does it cost to have someone make a cheap but functional head gasket? With the differences in the bore, what adjustments actually need to be made?