Atacama Yellow 35is build thread

[Pondrew]

Hi Peter,
I hope you had a good xmas. The following is genuine (as I have had an epiphany) and am interested.
I have not read ALL the thread, so sorry if this has been covered:
Have you changed the N54 pistons and rods for the 500bhp target, or are you going to?
The reason I ask is that I know with the N54, Alpina changed the pistons and conrods for Mahle forged items; presumably as a precaution for uprating the power. I believe Alpina offered the N54 with a maximum of 400bhp and 550nm. As you are going far beyond this, I am interested in your thoughts.
Andy

 

[Argyll Andy]

Just wondering if anyone has changed to non run flats with adaptive suspension and if it makes that much difference as I find mine no problem?

I went from almost new, 7mm+, 19’ Bridgestones RFT’s to MPS4S’s and the difference was night and day. As much as they gave a greater confidence in the car when tramping on. The types of roads I’m driving regularly are single carriageway reasonably twisty stuff.

The RFT’s you hoped there was enough grip and handling to see you through the corner, the NRFT’s you knew there was :wink:

 

[Pondrew]

I went from almost new, 7mm+, 19’ Bridgestones RFT’s to MPS4S’s and the difference was night and day. As much as they gave a greater confidence in the car when tramping on. The types of roads I’m driving regularly are single carriageway reasonably twisty stuff.

The RFT’s you hoped there was enough grip and handling to see you through the corner, the NRFT’s you knew there was

Maybe that's as much to do with the compound as anything. MPS4s are a very soft compound, so heat up quickly. Bridgestone Potenzas are made of concrete and don't.

 

[Argyll Andy]

I went from almost new, 7mm+, 19’ Bridgestones RFT’s to MPS4S’s and the difference was night and day. As much as they gave a greater confidence in the car when tramping on. The types of roads I’m driving regularly are single carriageway reasonably twisty stuff.

The RFT’s you hoped there was enough grip and handling to see you through the corner, the NRFT’s you knew there was

Maybe that's as much to do with the compound as anything. MPS4s are a very soft compound, so heat up quickly. Bridgestone Potenzas are made of concrete and don't

Not going to disagree but with my driving style in the Z4 they should heat up eventually, still had the same OFFS!!! Feeling on the final corner returning home on the RFT’s. I also have another car in the house running 18’ NRFT’s Bridgestones, completely different to the RFT’s

 

[Pondrew]

I also have another car in the house

You should really keep it outside, or in a garage

 

[B21]

Hi Peter,
I hope you had a good xmas. The following is genuine (as I have had an epiphany) and am interested.
I have not read ALL the thread, so sorry if this has been covered:
Have you changed the N54 pistons and rods for the 500bhp target, or are you going to?
The reason I ask is that I know with the N54, Alpina changed the pistons and conrods for Mahle forged items; presumably as a precaution for uprating the power. I believe Alpina offered the N54 with a maximum of 400bhp and 550nm. As you are going far beyond this, I am interested in your thoughts.
Andy

So here’s my dissertation with the benefit of accumulating hindsight….

BMW built the N54 as their first modern generation turbo charged car…coming to market in 2006.

Generally it was over engineered for the intended task..300-350 BHP it had a forged crankshaft and forged rods..it had cast pistons.

The BMW/Alpina standard is to be able to hold maximum rated power for hours at a time if required.

Given when the decision was made by Alpina to use the N54 in 2006, little operational experience of the engine was known, if any.

So Alpina went down a ‘traditional’ route to gain more power, lower compression ratio than the stock N54..9.3 vs 10.2 plus a lot more boost.

BMW themselves had already selected a special version of the piston for the N54 over the NA N52..Alpina went further with Germanic enthusiasm..so lower compression ratio and forged..a good, prudent choice.

So it’s both a good marketing pitch..and it’s prudent.

What nobody knew was just how robust and tune-able the N54 would be..in theory a cast piston, open deck design signals limitations.

It quickly became clear , in the hands of third parties, just how easy and scalable the N54 is..even BMW went down the route later 5 years after the launch with a re-map on the 35is.

So with hindsight were the forged pistons required? Probably not but a good insurance policy.

Seems N54s can run 600-700 crank BHP on stock pistons.

Again, in my journey and many others, we are not intending / able to use whatever full power is produced for more than 30 seconds.

Even at 400 BHP before the big turbos the car would hit 155mph and the speed limiter in less than 30 seconds..

Therefore the trade off is that transient use of power above 400 BHP is limited and the existing cooling systems , given the airflow over the radiators, will ensure no ‘meltdown’…as discussed prudent tuning at these elevated levels use very rich mixtures..something a NA ICE can’t take advantage of, as they need close to stoichmetric mixtures to achieve their peak hp / torque.

 

[Pondrew]

So here’s my dissertation with the benefit of accumulating hindsight….

BMW built the N54 as their first modern generation turbo charged car…coming to market in 2006.

Generally it was over engineered for the intended task..300-350 BHP it had a forged crankshaft and forged rods..it had cast pistons.

The BMW/Alpina standard is to be able to hold maximum rated power for hours at a time if required.

Given when the decision was made by Alpina to use the N54 in 2006, little operational experience of the engine was known, if any.

So Alpina went down a ‘traditional’ route to gain more power, lower compression ratio than the stock N54..9.3 vs 10.2 plus a lot more boost.

BMW themselves had already selected a special version of the piston for the N54 over the NA N52..Alpina went further with Germanic enthusiasm..so lower compression ratio and forged..a good, prudent choice.

So it’s both a good marketing pitch..and it’s prudent.

What nobody knew was just how robust and tune-able the N54 would be..in theory a cast piston, open deck design signals limitations.

It quickly became clear , in the hands of third parties, just how easy and scalable the N54 is..even BMW went down the route later 5 years after the launch with a re-map on the 35is.

So with hindsight were the forged pistons required? Probably not but a good insurance policy.

Seems N54s can run 600-700 crank BHP on stock pistons.

Again, in my journey and many others, we are not intending / able to use whatever full power is produced for more than 30 seconds.

Even at 400 BHP before the big turbos the car would hit 155mph and the speed limiter in less than 30 seconds..

Therefore the trade off is that transient use of power above 400 BHP is limited and the existing cooling systems , given the airflow over the radiators, will ensure no ‘meltdown’…as discussed prudent tuning at these elevated levels use very rich mixtures..something a NA ICE can’t take advantage of, as they need close to stoichmetric mixtures to achieve their peak hp / torque.

I take that is a NO then? :lol:
Certainly can't criticise your research

 

[B21]

So correct..no plan to change intervals…Alpina only changed the pistons AFAIK, the stock rods are forged..it’s good when people ask detailed questions which merit an appropriate technical response rather than responding by simply expressing an opinion without reference to how that opinion was formed

Looks like your’s will be tricky to tune due to the custom ECU.. :tumbleweed: will be a struggle with only 360 BHP and 500nm… :rofl:

 

[R.E92]

The original Alpina B3 uses the same ECU as the pre 2009 335i, and the B3S uses the same as 2009+ models. The software is a little different but it can be tuned just the same.

If I had a B3 i'd probably just upgrade the ECU to the B3S one and skip a tune. The B3S was already pretty close to maxing out the standard turbos.

 

[B21]

The original Alpina B3 uses the same ECU as the pre 2009 335i, and the B3S uses the same as 2009+ models. The software is a little different but it can be tuned just the same.

If I had a B3 i'd probably just upgrade the ECU to the B3S one and skip a tune. The B3S was already pretty close to maxing out the standard turbos.

Ah thanks for the update / correction..R.E92..

So the ‘Alpina specific ECU’ was a bit of marketing fluff or just referring to same ECU hardware (N54) but different software?

 

[Pondrew]

Looks like your’s will be tricky to tune due to the custom ECU.. will be a struggle with only 360 BHP and 500nm…

I wasn't contemplating it TBH. Without an LSD I can't keep the rear in a straight line as it is with only 500nm.
Also, as has been said before, Alpinas are a very niche market. Seems if you 'fiddle' with them it kills the value.

 

[B21]

Looks like your’s will be tricky to tune due to the custom ECU.. will be a struggle with only 360 BHP and 500nm…

I wasn't contemplating it TBH. Without an LSD I can't keep the rear in a straight line as it is with only 500nm.
Also, as has been said before, Alpinas are a very niche market. Seems if you 'fiddle' with them it kills the value.

Yes, seems once you go past 400nm / 300 BHP it all gets frisky on the rear end, especially in the wet…I assume you have the e-diff type fitted to most other BMWs of that era that shut the power down / brake the spinning wheel as a faux LSD? :driving:

I’d think the Alpina elite would have a meltdown if you even changed a badge.. :tumbleweed: :rofl:

 

[R.E92]

The original Alpina B3 uses the same ECU as the pre 2009 335i, and the B3S uses the same as 2009+ models. The software is a little different but it can be tuned just the same.

If I had a B3 i'd probably just upgrade the ECU to the B3S one and skip a tune. The B3S was already pretty close to maxing out the standard turbos.

Ah thanks for the update / correction..R.E92..

So the ‘Alpina specific ECU’ was a bit of marketing fluff or just referring to same ECU hardware (N54) but different software?

It's the same hardware, different software. I have a copy of it on my PC for the B3S. It's a good reference for custom tuning.

 

[Pondrew]

I’d think the Alpina elite would have a meltdown if you even changed a badge.. :tumbleweed: :rofl:

People have been stoned to death for a lot less.

 

[Pondrew]

It's the same hardware, different software. I have a copy of it on my PC for the B3S. It's a good reference for custom tuning.

Someone told me the B3s has redesigned intake pipework (and/or intercooler) to the B3 too. Don't know if this is a BMW change on the LCI or not.
Anyway off topic, this is about Pete's.

 

[B21]

The original Alpina B3 uses the same ECU as the pre 2009 335i, and the B3S uses the same as 2009+ models. The software is a little different but it can be tuned just the same.

If I had a B3 i'd probably just upgrade the ECU to the B3S one and skip a tune. The B3S was already pretty close to maxing out the standard turbos.

Ah thanks for the update / correction..R.E92..

So the ‘Alpina specific ECU’ was a bit of marketing fluff or just referring to same ECU hardware (N54) but different software?

It's the same hardware, different software. I have a copy of it on my PC for the B3S. It's a good reference for custom tuning.

I’ll add it to the book I’m writing the E89

 

[B21]

Received my VSRF wide bore inlet pipes today.

These babies connect the outlets from the air inlet box (or dual cone inlet type filters) to the turbo charger inlets.

Unlike the air coming out of the turbos which can be over twice the atmospheric pressure the inlet side relies on a good clean flow at more or less atmospheric pressure.

The 35i Z4 is alleged to be generally less obstructed and more robust on its intake plumbing the N54 fitted to other cars. So whether this is going to make much of a difference is unknown (to me)

However since I’m not planning on re-visiting this issue when the uprated turbos are fitted (which have wider inlet tracts 2”) I thought I’d do a belt n braces approach and update as much of the total intake related plumbing as I could.

I’m still holding on to the idea of the stock air box and OE filter..that may well prove restrictive to the maximum amount of extra ponies that can be released..however it’s very easy to change those parts , unlike most of the turbo related parts.

Awaiting the other parts which should get shipped from the States sometime next week before working out a fitment plan.

 

[B21]

Treated myself to a new 15 amp charger to help me during programming / code updates when working on the car.

Several of the coding protocols call for the ignition on, engine not running, which generates a substantial current drain (over 20 amps)..

There’s a danger since normally an E89 battery is never fully charged that a ‘critical event’ could happen, ie the on board ECUs shut down due to a drop in main bus volts and possibly corrupt themselves in the process.

My work regime is, now, always to fully charge the battery with my normal 4 amp Lidl chargers..however if messing around for a long time it’s possible to drain the battery to the point where something goes Pete Tong.

So with 15 amps going in and a fully charged 80 AH battery, tears of such a nature can be avoided

I’m not sure I would trust it as a long term float charger and it’s traditional case renders it unsuitable for outdoors use.

 

[Flyingfifer]

In terms of diameter how much wider are the new pipes to he old?

 

[B21]

In terms of diameter how much wider are the new pipes to he old?

Hi Wullie, not sure how wide the OE pipes are..pictures show a number of constrictions in the design…the necks are 1.75”…

You can order the replacements in either 1.75 or 2 wide..the bigger turbos have a 2” flange hence the change

https://www.vr-speed.com/vrsf-oem-location-high-flow-silicone-inlet-intake-kit-n54-07-10-bmw-135i-335i-535i-1m-z4.html