Ms43 Vs ms45 turbo application

[LittleZ4]

Morning all. I have the chance to purchase a turbo kit off a 330i and am hoping you knowledgeable lot may have a few helpful pointers.

The kit has been running on the 330 for about 3k miles with no issues (built by a BMW mechanic as his own car) so I'm not too concerned about the kit itself. Everything is included to make it run including some 440 injectors (off a volvo originally??)

Anyway my main concern is the ecu side of things, on the 330 he is running stock map on an MS43, where as on the Z4 it will be MS45. Will I be able to run a stick MS45 ECU for the time being? The boost is currently set to 7psi. I've read that the ecu has a torque limiter which kicks in around 450nm? Would I be better off downgrading to MS43? (Or completely the other way to an MS45.1 for wideband 02 sensors?? Although I'd have to say goodbye to the sport button.)

Ultimately it will get a map or standalone, if not just to make sure everything is as it should be for forced induction but I'd like to get everything installed and tested asap.

Any help would be greatly appreciated.

 

[pokeybritches]

It depends on who will be doing your tuning. Not many tuners know how to tune MS45 for higher levels of boost, and there’s a lot more MS43 info out there.

Ideally you should get it tuned on MS45. You’ll lose a handful of features if you make the conversion to MS43. Here’s a writeup I did which discusses of some of what’s required, beyond the normal spark and fueling tables:

https://www.renovelo.com/forum/viewtopic.php?f=11&t=1575&p=2157#p2157

If you’re planning to tune yourself, MS45 is not a good ECU to start with. No need to go standalone on 7 psi of boost. I’m running flex fuel with an AFD PROFLEX Commander, and the stock pump keeps up just fine with E60 on 10 psi of boost (I haven’t tested further).

The Volvo injectors are a common upgrade for the M54, and there’s a decent amount of injector data floating around out there. I prefer Porsche 997tt injectors, as they are reliably consistent and well-built.

 

[GuidoK]

Isnt a 650cc/min injector a bit large for a 7psi FI application?
I mean the stock injectors are 236cc/min(@3bar) and can still go a long way (up to 300hp).
His max need at 7psi boost would only be ((14.7+7)/14.7)*236=348cc/min related to the stock injectors.

 

[LittleZ4]

And it's the little bits like this I need a point in the right direction with. I know the kit works, I've been out in the car it's still on, it's just the ecu side of things (as well as probably space in the engine bay :roll: )
I personally won't be mapping as I'm not that confident yet, happy to try, worried it'll go bang!
I have a big community of car people around me, garage owners, drifters, drift car builders and so on. So between us we "might" know someone who knows someone.

I just don't want to part with the cash if the ms45 is of no use. I kinda need it up and running quickly once we start as this is my daily.
I'll check that link out, the guy selling as also pointed me in the direction of that website.

 

[pokeybritches]

Isnt a 650cc/min injector a bit large for a 7psi FI application?
I mean the stock injectors are 236cc/min(@3bar) and can still go a long way (up to 300hp).
His max need at 7psi boost would only be ((14.7+7)/14.7)*236=348cc/min related to the stock injectors.

They do have some extra headroom, which is nice for running ethanol (requires 30% more fuel flow) and capacity should OP decide to raise boost. The real benefits are the injectors’ consistency and known injector data. I was able to get mine to run smoother than the VF injectors, even though VF injectors are 30 lb/hr (OEM are 24 lb/hr). That’s because minimum injection time and dead times are known. I would take a slightly oversized quality injector with known characteristics over a smaller unknown injector any day.

That being said, the “Volvo turbo” 440cc/min (42 lb/hr) have known characteristics as well. I’m not familiar with their consistency or quality.

 

[pokeybritches]

And it's the little bits like this I need a point in the right direction with. I know the kit works, I've been out in the car it's still on, it's just the ecu side of things (as well as probably space in the engine bay :roll: )
I personally won't be mapping as I'm not that confident yet, happy to try, worried it'll go bang!
I have a big community of car people around me, garage owners, drifters, drift car builders and so on. So between us we "might" know someone who knows someone.

I just don't want to part with the cash if the ms45 is of no use. I kinda need it up and running quickly once we start as this is my daily.
I'll check that link out, the guy selling as also pointed me in the direction of that website.

It would be tough to make it work on a daily, because no one has an OTS turbo tune as far as I know. There would be some growing pains. Quality, fast, and cheap - usually you only get 2 of them, but in this case everything would need to be custom so I think you’d only get 1.

I have an MS43 ECU with EWS delete and harness sitting in my garage because I’d become frustrated with MS45. I was about three days away from making the switch before someone showed me the intake manifold tables, which I was able to use to tune the car and iron out all the issues. I had over 130 tunes before all was said and done.

An MS43 swap isn’t straightforward, and you do lose some minor capabilities when going backwards from MS45.

 

[LittleZ4]

Making me wonder if it's indeed worth it for a daily? I guessing it would be useless on a stock ECU......no tune.

 

[pokeybritches]

You definitely need a tune, especially with those injectors. You can get away with stock ignition maps to an extent (though it’s not ideal). The stock ECU can only trim out so much fuel - 30% on an MSS70 ECU I fixed that was running 550cc injectors and supercharger with no tuning changes... the car drove like absolute crap until I saw what the previous tuner had done; I’m not sure how much fuel the MS45 ECU can trim out because I’ve never had one come to me that messed up.

If the intake manifold model tables aren’t adjusted, the car will drive like ESS TS and higher boost VF kits - less power than it should have at best... hesitation, bogging, and timing cuts at worst.

The stock target lambda tables aren’t set up well for boost either. They target lambda 1.0 at part load, and a significantly richer lambda value at full load. If you’re slowly feeding in throttle, it will feel like you hit a wall when the ECU switches from part load to full load. I changed some things to make my car target progressively richer mixtures as load increases, which eliminated the binary on/off feel. MS45.1 has these changes incorporated with the stock ECU, since it has wideband O2 sensors and can target lambda values other than 1.0. It took some trial and error to get AFR correct while spraying water/meth. These are just some of the challenges you’ll face with tuning the stock ECU, and they have to be done if you want the car to drive properly.

It is feasible to daily a turbo, but you’ll need to give yourself a couple months to sort everything out.