Remap 35i

[SO8]

It's a DCT 35i with a remap to approx 400bhp (stock hardware targeting 17PSI in the midrange and 15PSI further up). I have no problems with the extra power


James: If you're worried about keeping the warranty the LSD will most certainly invalidate any cover on the gearbox. I think most LSDs will alter the final drive.

That's really interesting - did you change anything else or just go with more power on it's own?

At first I thought it must be a faulty 35is (mine) - but drove half a dozen now & they have all been the same under power... weird. I see the issues that have been reported by just about every tester who had driven the car anywhere near the limit.... twitchy unpredictable swifts in the chassis / poor traction (at speed)... gearshift lurch upsetting the chassis under max load.... cornering lurch at speed... the lot. at it's worst it's like the front end of the car isn't connected to back end - press on hard & it tries to kill you.

Same road - same day - same speeds in a e92 m3 & no issue or drama.

You must have the 'good one'

My experience is that the stock car feels unstable when driven aggressively (only reason for more power surely is to drive aggressively?)... ah well... each to their own

Matt

The handling is unsophisticated I agree ... and takes getting hold of by the scruff of it's neck but it will do it. My Z4M Roadster was far easier to control but was slower. The run flats make it hard work. I think they are a significant issue. It skips and jumps but I have never felt likely to kill me. It just takes more effort than some more accomplished cars. It takes the power OK, will take some more but not too much IMO.

 

[R.E92]

If I launch the car hard it will squirm. But that's part of the pleasure.

Once I'm up to speed I really don't feel any instability especially not in this warm dry weather. I have even tuned the wastegate PID control in the DME to be very fast acting by upping the P and D factor so the car builds boost a lot faster than most tuned cars and I still don't struggle with traction.

There's plenty of people with more aggressive tunes than me running 4PSI more boost and still not concerned about traction. But then all of those people will have swapped over to Michelin PSS. Most, like me, just stick with 265 on the rear but some go up to 275 for a little more grip.

I think most reviewers compare the Z4 to the Cayman. In that light then the Z4 looks fat and clumsy. But then so do most cars.

 

[Timdon]

I just though a 35i with adaptive suspension could cope with a stage 1 remap

 

[SO8]

I just though a 35i with adaptive suspension could cope with a stage 1 remap

With a gentle right foot it will.

I managed a Golf GTi Edition 30 that went from 230bhp (it's restricted level as it was the same engine as an Audi S3 but detuned)to 300bhp. Floor it and all that happened was wheel spin and massive axle tramp. Pull away, let the DSG short shift into 2nd gear and it became a serious tool !

I would expect the same applies to a 370-400bhp Z4 35i/35iS ... Getting the power down in less than ideal conditions will result in loads if wheelspin and not much joy. Let it pull away, ease your foot off slightly, it drops into 2nd then absolutely flies and would destroy most things it comes across :evil:

I would love to try it but will not risk my car or the warranty - especially with my experience with the Z4 !

 

[matthurley]

I just though a 35i with adaptive suspension could cope with a stage 1 remap

With a gentle right foot it will.

I managed a Golf GTi Edition 30 that went from 230bhp (it's restricted level as it was the same engine as an Audi S3 but detuned)to 300bhp. Floor it and all that happened was wheel spin and massive axle tramp. Pull away, let the DSG short shift into 2nd gear and it became a serious tool !

I would expect the same applies to a 370-400bhp Z4 35i/35iS ... Getting the power down in less than ideal conditions will result in loads if wheelspin and not much joy. Let it pull away, ease your foot off slightly, it drops into 2nd then absolutely flies and would destroy most things it comes across :evil:

I would love to try it but will not risk my car or the warranty - especially with my experience with the Z4 !

What 0-60 time were you getting in the remapped Golf?

 

[SO8]

I just though a 35i with adaptive suspension could cope with a stage 1 remap

With a gentle right foot it will.

I managed a Golf GTi Edition 30 that went from 230bhp (it's restricted level as it was the same engine as an Audi S3 but detuned)to 300bhp. Floor it and all that happened was wheel spin and massive axle tramp. Pull away, let the DSG short shift into 2nd gear and it became a serious tool !

I would expect the same applies to a 370-400bhp Z4 35i/35iS ... Getting the power down in less than ideal conditions will result in loads if wheelspin and not much joy. Let it pull away, ease your foot off slightly, it drops into 2nd then absolutely flies and would destroy most things it comes across :evil:

I would love to try it but will not risk my car or the warranty - especially with my experience with the Z4 !

What 0-60 time were you getting in the remapped Golf?

No idea of what exactly but people on forums who had similar maps and got it professionally timed showed about 5.5 to 60 as opposed to VW claim of 6.6 to 62. IIRC 12.5 to 100mph was mentioned.

 

[Garvin]

. . . . . . . . Traction & suspension is the first thing I would look to improve before worrying about adding more power.

In order I would go tyres first, then a LSD, then more power.

^^^^^This. RFTs are, IMHO, the limiting factor on this car. I'm on my second 35iS and the first would squirm and light up the traction warning under full bore acceleration on anything but the smoothest surfaces. Any undulations and or broken surfaces would herald a dash like a Christmas tree. With traction control off (or at least minimised) the whole car would squirm severely on some surfaces - good fun, but not the height of handling prowess! Cornering on bad surfaces resulted in a lot of skipping and jumping at the back end.

This bad behaviour has been reduced markedly on the second version (same spec as the first) and I put it down to improvements in the tyre technology for the RFTs. Well used roads, where I had to be mindful with the first car, are now not a problem but the traction warning will still light up on undulating surfaces but now only occasionally. It still skips & hops at the back but nowhere near as bad as the first offering.

A decent set of high performance tyres and an LSD would, I think, do wonders for the car!

 

[Z4M-2006]

I think what we have to remember is how powerful the cars actually are...

Something with 340bhp is gonna squirm and buck under full bore acceleration..

340bhp is a lot of power for any car to keep under control... Turn off the Traction control and learn to drive the car without any driver aids, then go from there..

 

[Garvin]

I think what we have to remember is how powerful the cars actually are...

Something with 340bhp is gonna squirm and buck under full bore acceleration..

340bhp is a lot of power for any car to keep under control... Turn off the Traction control and learn to drive the car without any driver aids, then go from there..

My weekend 'toy' has 380bhp, absolutely zip in terms of traction/stability control and tracks straight and true under full bore red line up changes. It also corners like it is on rails no matter the road surface. The Z4 really wouldn't see which way it had gone on the twisties!

Oh, and it's 18 years older than the Z4!

 

[Z4M-2006]

And it is what ?

I guess it cost 3 times more than a Z,and its a dedicated sportscar with high end suspension components..

 

[R.E92]

My guess is a 964 turbo!

 

[Garvin]

Not a Porsche, not a turbo, it does have 20 year old adaptive suspension though - but then again, the 35iS has much more modern adaptive suspension! It is kitted out with Michelin Pilot Super Sport tyres all round as well.

It's this:

 

[Z4M-2006]

Your honestly pitching a mid engined italian supercar against a Z4 ?

I have fixed a few 355's in my day...... Lovely lovely thing.....The engine is a masterpiece,the bulid quality not so much..

 

[Garvin]

On paper, the performance of the 35iS and F355 are very, very close. On the road they are chalk and cheese! The Z4 has a nice satisfying rumble to it where the Ferrari has a spine tingling howl, especially nearing the 8.5k red line!

A spirited drive in the F355 really does show the Z4 for what it is - a very nice, fast, comfortable GT car but not a 'real' sports car. The point is that not every car with over 300bhp squirms when the hammer is put down, the F355 could easily handle 500 or so ponies without drama, especially on the brilliant MPSS tyres.

Yes the engine is a masterpiece and, yes again, the design/build standard of the bodywork and fittings is, TBH, a bit, or maybe a lot, pants. But all the important bits, engine, transmission, chassis, suspension, steering and brakes are top notch. The sound of the flat plane crank V8 is, of course, one of the wonders of the world!

 

[petrolhead]

I see DTUK are doing a add on box, anyone tried it?
http://www.diesel-performance.co.uk/vehicle-bmw_z4-(e89)_sdrive-35i-n54-306ps-twin-turbo

I see a lot of good things about Evolve

 

[SO8]

I see DTUK are doing a add on box, anyone tried it?
http://www.diesel-performance.co.uk/vehicle-bmw_z4-(e89)_sdrive-35i-n54-306ps-twin-turbo

I see a lot of good things about Evolve

TMC do a box as well. A lot of the M135i people are doing it with good results on rolling roads.

I looked at a DMS remap having had a map off them for my 330d LCI which was brilliant. They have said they can adjust the map to what I want - i.e not too much as opposed to pub bragging rights but unusable power.

The issue with all of these things is warranty to me - I am not taking any chances ... outside warranty may be another thing :evil:

 

[R.E92]

Those tuning box things are nasty.

That one will just be a box of resistors that makes the car thinks it's producing less boost than it actually is.
If the DME requests 8PSI and the pressure sensor reports back 8PSI then the car will leave the wastegates alone. If however you plug that unit it then it scales down the feedback value for boost pressure so now the car sees that it's only making 5PSI and closes the wastegates a little more until the value it sees is 8PSI.

The DME is load based and part of the load equation is reported boost pressure. So now the car is producing a load value of 140 but the DME thinks it's still producing the stock value of 110. Because the car still thinks it's making 110 it will not adjust the engine timing to compensate for the increased boost. It will also still operate the gearbox as if it were at 110 load which means the clamping pressure of the clutch packs will be too low and allow the disks to slip more than designed during shift.

Because the timing hasn't been adjusted to reflect the actual load value then the car is running more timing than it should be. So you're just leaning on the engine knock sensors to prevent the car lunching itself.



These tables show the load targets in the ECU along with the fuel and ignition timing tables of a stock car. You can see here that these two pretty crucial tables are scaled using the load value across the top and revs down the side.
It doesn't take a genius to realise that just fudging the feedback values to the ECU is less than ideal.

More complicated piggyback units like the JB4 have workarounds for a lot of the common problems but still fail on this point. Because of this the advice from the likes of Terry at BMS who make the JB4 tuning boxes is to combine it with a flash tune. Which in my opinion speaks volumes about the importance of a proper tune.

 

[SO8]

Those tuning box things are nasty.

That one will just be a box of resistors that makes the car thinks it's producing less boost than it actually is.
If the DME requests 8PSI and the pressure sensor reports back 8PSI then the car will leave the wastegates alone. If however you plug that unit it then it scales down the feedback value for boost pressure so now the car sees that it's only making 5PSI and closes the wastegates a little more until the value it sees is 8PSI.

The DME is load based and part of the load equation is reported boost pressure. So now the car is producing a load value of 140 but the DME thinks it's still producing the stock value of 110. Because the car still thinks it's making 110 it will not adjust the engine timing to compensate for the increased boost. It will also still operate the gearbox as if it were at 110 load which means the clamping pressure of the clutch packs will be too low and allow the disks to slip more than designed during shift.

Because the timing hasn't been adjusted to reflect the actual load value then the car is running more timing than it should be. So you're just leaning on the engine knock sensors to prevent the car lunching itself.



These tables show the load targets in the ECU along with the fuel and ignition timing tables of a stock car. You can see here that these two pretty crucial tables are scaled using the load value across the top and revs down the side.
It doesn't take a genius to realise that just fudging the feedback values to the ECU is less than ideal.

More complicated piggyback units like the JB4 have workarounds for a lot of the common problems but still fail on this point. Because of this the advice from the likes of Terry at BMS who make the JB4 tuning boxes is to combine it with a flash tune. Which in my opinion speaks volumes about the importance of a proper tune.

Interesting ... can you answer the following ?

Can the N54 ECU be reflashed via the OBD port (which I am told it can - contrary to my belief it was too 'new' for this).

If so, can BMW detect a remap if all fault codes created during the reflash process on the various ECU's (where they lost communication with the main ECU) be removed and no trace on any 'hidden' area of the extra boost/timing used when the car was reflashed also be removed ??

Loads of people claim their remaps are undetectable ... DMS claim this but not in relation to their opening of the main ECU (which they did on my last car once it was out of warranty). I found remaps actually make the car drive better if a good one but do not want the hassle of BMW telling a future owner it has been mapped ...

 

[R.E92]

Yes the N54 is fully re-flashable in all it's iterations (Even the 1M).
The N54 comes with two different DME chips, the MSD80 and MSD81. You can re-flash both with great ease.

Most remaps will disable the tune related error codes. The "Toggles" section in the screenshot above contains those functions. It's likely that DMS will just disable the tuner codes so they don't appear on a scan.
I personally wouldn't risk it though since a black flag against the car means you're on your own.
Another possibility is that the remap they apply will be based on old DME software. The current software revision for our cars is INA0S. If DMS downflash the car to something like I8A0S to perform the remap then the dealer will see this and either try to update it and remove the remap or notice that the car should be on the current software and realise that it has been flashed elsewhere.

They are also very accustomed to driving stock cars. So as soon as Dave the test driver takes your 35is for a post service spin he will realise instantly that the car is tuned (all that squirming under acceleration the Z4 suffers from :wink: ).

Personally I wouldn't bother with any of the remap providers in the UK. They may know enough about tuning to get some more power out of the car but will not be on the same level as a proper N54 tuning expert.
The main two camps for N54 tuning are ProTuningFreaks and WedgePerformance which are both US based. Luckily for us UK based people is that the standard method of tuning is e-tuning the car with a device like a COBB AP or using an android phone and the N54 MHD Flasher app which is all done by sending engine data logs to the tuner and them sending you a new file to load to the car with adjustments made with respect to the data log.

I think e-tuning is a lot better than the standard dyno tuning that garages often use because with e-tuning you are tuning to road conditions where the engine is under load and the airflow is true rather than fan provided. You also will be accounting for heat soak and managing the intake air temps which are crucial with these engines.

 

[petrolhead]

Any thoughts on the Superchips map then