3.0Si Remap - thoughts?

[Ed Doe]

Hi all,

Bit of background; I have an '06 Z4 Coupe 3.0si Sport, which after ~4months of ownership I am very fond of... however...

I have a few bug-bears as regards the driving experience...

1. The horrid tailing off of the power past 6,500ish rpm. It’s a sports car, it should pull hard to the redline, which brings me on to the next point;
2. Soggy, artificial rev limiter. Rather than a decent one, it’s electronically mapped in to completely tail the torque off so the redline is reached at a significantly more sedate, and less offensive pace/volume! Again, it’s a sports car, I want a bit more drama, not this limp wristed tailing off. In my opinion it would also significantly improve the pick-up when changing to the next gear, as I find it tends to drop the revs ever so slightly too low if you change at 6,500rpm…
3. Raise rev limit to 7,300rpm.
4. Remove/map out the torque limit in 1st – yes I know it’s there because you don’t need all the power in first, but it’s annoying; I want to decide how much power goes rearward on the throttle, thank you!
5. Over-assisted steering in 'Sport mode'. It’s not that much of a problem in non-sport mode, but it does I find tend to make it a bit vague in general, something I want to dial out a lot more when putting it in sport mode for fun driving. I could be wrong, and this could be to do with needing suspension refreshing, but I’d rather like to reduce the assistance in sport mode in the hope of gaining a bit more feedback, and a bit more resistance immediately off-centre…

Has anyone else on here experimented with mapping the above parameters, and if so what was the end result like to drive? Were they worth doing? I’ve been in touch with a reputable mapper in the Bournemouth, and have discussed my thoughts and what I’d like to achieve, and he has said it’s all achievable, and he will save the OEM parameters to revert to if I’m unhappy with the results.

I would like to highlight that I'm not going for, or expecting a super duper heap more power or torque; just trimming/smoothing of the existing torque curve, and modification of the above parameters...

Thoughts?

Thanks in advance

Ed

 

[Evil_elvis]

I pretty much agree with all of your wishlist, with the exception perhaps of the steering in sport mode - personal preference I guess.
So I'd also like to "fix" some of these issues.

I'd be very interested to hear if anyone has achieved any of these and if there are any possible power gains (wishful thinking maybe)

Just to add something to the thought process, I'm not sure that the "artificial" redline is exactly that. There may be a good reason the torque falls off after 6500rpm, some engines just can't produce power higher up the rev range. Valve bounce I think springs to mind, or having HLAs instead of solid valve lifters. This is one reason all //M cars and Type R Honda's need the valves re-shimming and rev to 8k (solid valve lifters). Its not something you can dial in from an ECU map....

:driving:

 

[Ed Doe]

Thanks, glad to know I’m not the only one that wants to put it right! So how do you find the steering then? I’m not convinced I’ve tracked down the source of my potential issue, but my steering seems to ‘kick’ in response to very slight steering angles. I drive some rather cambered roads to work, and will always expect some level of tramlining/steering feedback due to the horrid road surface, but to me it feels more like the EPAS actually causes the steering to ‘pulse’ against my input occasionally, trying to pull the steering back to centre. If it’s reacting to the cambers in the road, I want to reduce it in sport mode so I can enjoy the drive, as in the summer it really is cracking! I’m taking the car to TWG in Camberley next Friday in any case for Inspection 2, and have requested they inspect the suspension particularly with a view to addressing this problem, so we’ll see….

In regard to the engine power production; firstly I’m sure the rev limiter can be raised on these engines, and I’m also sure 7,300 will be detrimental to the valves. Crikey, I’d be shocked if BMW had built so little tolerance into the valve system, when some of the Peugeots I’ve had had been cammed and mapped to rev past 8 on standard lifters! As always though, I’m more than happy to be corrected on the subject; I’ve only done a limited amount of research into the N52 engine in the last few months…

In my opinion, the difference of those few hundered rpms will drop the engine right back on the power when changing gear, and make it a much sportier drive as a result... if it’s possible to do without any effect on the valvetrain…

 

[hopz121]

Have a chat to Jason at BW Chiptune, he is a highly regarded Tuner in the BMW world and not a million miles away from guidford. He knows his stuff and will set the car up correctly with Before and after Dynos etc.

Ash

 

[Evil_elvis]

Oh man the kick and tramlining is ridiculous! But can also be down to the runflats.

 

[Evil_elvis]

Hi.

Maybe my post was badly worded, but I didn't say that raising the rev limit would damage the engine.

IMHO the inherent issues with HLAs mean that they aren't going to produce more power much past the redline. Especially since you've already pointed out that the torque clearly tails off at the top end.

I'm not dismissing what you are trying to do, just saying that chasing revs isn't always going to work

 

[Ed Doe]

I don't have run-flats on mine, I bought the car on the Falkens that seem fairly well rated on here. I replaced them (they were close to the limit when I purchased the car) with new Eagle F1 Assymetric 2s, and had a proper geometry set-up by Back on Track motorsport, and although improved somewhat this wierdness is still there...

I am nonetheless rather encouraged that it isn't just me being a complete pedant! I have been known to go a bit overboard as I like to have my cars driving exactly as they should...

EDIT: in response to your latest post, don't get me wrong either! I agree that chasing revs on a car with cams optimised for torque is a non-starter, but in my opinion the map is currently reducing the torque request past 6600rpm to create a nice soft limiter for all those first owners whose driving talent is inversely proportional to their spending power
Take a look at the graph on page 9 of the following pdf; http://www.kneb.net/bmw/E90/04_N52 Engine.pdf. I realise this relates to an N52B30 in slightly different tune to ours (190kW rather than 196kW), but notice how the torque & HP start to sharply drop immediately past 6600rpm with the OEM map. I'm convinced our engines are mapped with a very similar 'tail-off', and it is here that I'm interested in gaining. Even if it starts to tail through the innate characteristics of the camshaft design, it will still permit a sportier 'peak near the redline' than we have currently got.

Is my thinking anyway!!

I totally take on board what you're saying re HVA's, and their inherent weakness a higher revs, and I'm hoping we will have a bit of a margin between the 7k current soft limiter, and the 7,300rpm limiter I'm hoping to reach. Anyone with any first hand experience of having raised the limiter, please do give us some feedback at this point!!!

 

[Evil_elvis]

That tail off of the power is most likely because the engine can't produce any more torque.

 

[Evil_elvis]

This thread has lots of comments about raising the rev limiter, might be a good read:
http://www.z4-forum.com/forum/viewtopic.php?f=2&t=2545&start=0

 

[Ed Doe]

Thanks, that thread appears to be more aimed at the tuning potential of the 3.0i, with no specifics on raisingtthe rev limit. I'm hoping someone else has trodden this path before me and has some answers..!

 

[ocrx8]

Agreed on tail off of power over 6,500rpm - I remember reading reviews of the 130i (same engine) stating how it loves to rev right to the limiter, so I was expecting the same from the Zed!

 

[Evil_elvis]

Thanks, that thread appears to be more aimed at the tuning potential of the 3.0i, with no specifics on raisingtthe rev limit. I'm hoping someone else has trodden this path before me and has some answers..!

Really? Did you read it all?

Quotes:

---------
Not sure, but I know the 2.8 and 3.0 motors in the Z3 could have the power increased to 'near M' proportions by raising the rev limit. I think as standard they cut out at 6600 rpm, whereas the M was around 7600.
---------------
Sorry, you're right in that power = torque x rpm but I have had done just what you say and had my old 330ci remapped and the rev limit raised, it can only safely be raised to 7,000 and only just broke 250bhp, it will never get close to an S54 with just a remap, anything over 7,000 needs some serious head and bottom end work, the difference between an S54 and the 3.0 is HUGE,
----------
the power and torque curves start dipping after the 6000rpm mark in the stock M54 engines, simply raising the rev limit isn't going to get you any more power. even when supercharged, the M54B30 power curve plateaus after 6000
--------


Or to make it short for you, there are lots of posts backing up the fact that once a cars torque curve plateaus or drops off, you can't just raise the rev limit and expect power to increase.

 

[Ed Doe]

Whilst I just adore your condescending tone, I'd like to point out the following;

1. As I said, the post (along with the bit you quoted and the bit in bold) refers to the M54 engine. This is different to the N52 engine, and therefore what may be the limit for the M54 is not necessarily the limit for the N52. Hence my continuance in requesting those with any experience to offer their feedback on the matter.

2. As I've said already, I appreciate there will be limits to the power that can be made past the oem rev limit due to the cams and the hvas. I am interested in removing the electronically predetermined reductionin torque request by the ecu after 6600rpm (something that to my mind is abundantly clear on the graph on p.9 of the pdf I linked to). If by increasing the rev limit to 7,300, the torque curve can be extended even as it is reducing, it is almost certain there will be a benefit to the driving characteristics of the engine, as well as the power. And if it doesn't produce any power, what I will have gained is the ability to drop it back on the power band when I change up.

As per previous post, I will be contacting the BW chiptune, as well as the mapper I've already been in discussions with and see what their thoughts/experience is in the matter.

Thanks for the information anyway.

 

[Evil_elvis]

I am interested in removing the electronically predetermined reductionin torque request by the ecu after 6600rpm (something that to my mind is abundantly clear on the graph on p.9 of the pdf I linked to).

No need to be rude...i haven't been.

Why is the reduction in torque predetermined and electronic?
Why is this abundantly clear in the PDF/graph?

to my mind this is just the inherent limitations of the engine

 

[Evil_elvis]

I am interested in removing the electronically predetermined reductionin torque request by the ecu after 6600rpm (something that to my mind is abundantly clear on the graph on p.9 of the pdf I linked to).

No need to be rude...i haven't been.

Why is the reduction in torque predetermined and electronic?
Why is this abundantly clear in the PDF/graph?

To my mind this is just the inherent limitations of the engine


All the best and good luck in your quest.

 

[McKoval]

As a fellow n52 user I will be watching this topic with inerest.
But the linked pdf "cannot be found on the server"

As for the torque drop I've always wondered why it is like that? I mean if its engine limitation, they could've set the redlight at 6600rpm - the last 400rpm are useless anyway.
But if you could remap it to maintain torque up to 7000rpm I would be happy to have it like that

TapaTalking

 

[AndyBeech]

My logic would be that an 8 year old car, and no-one's done this as yet or no info on it means there's probably a reason why. Either reliability or cost versus reward I imagine make it not worth it. It's pretty well known that BMW squeezed pretty much all they could out of the N52 engine and agreeing with what others have said in that the characteristics you want to change are just limitations of the engine. I've yet to see a remap of the 3.0si that showed it as a worthwhile thing to do, infact I think someone might have done and then never posted about the results....

 

[Ed Doe]

McKoval; this is the relevant page of the pdf I linked to;

Evil_Elvis, apologies I think I misinterpreted the tone of your post after quite a week at work. I didn't mean to be rude, but having misread your post I took it the wrong way and got a bit miffed! I don't know if the pdf also didn't work for you, but at least as far as I can see, there is no plateauing of the power curve, it just spikes to a peak and drops immediately past it. That wouldn't correlate to the cams working outside their operational band; that would constitute a plateau and then a dropping off of the power available. Having driven the car as it is now for some time, I can certainly feel the power ween away at the top end which appears to correlate with the graph, and even if the current limiter (which I believe is 7k??) proves to be the end of the plateau, surely it's worth investigating extending the engine making full power right to this point?

Andy, there are from what I've read so far, there are a few people floating about on the forum who have had their N52 mapped, and I haven't yet read a bad word about the results, although as with all these things it is hard to prove explicitly what gains have been made without visiting an independent dyno before and after. As I've said though, I'm not really interested in setting the world alight with heaps more power, just optimising the delivery as much as possible in conjunction with the other parameters described in my OP, with the intended end-result of making it a bit more of a driver-oriented car!