Atacama Yellow 35is build thread

[Flyingfifer]

In relation to the 2l being more nimble than the 3l... remember that's inevitable and no amount of fiddling will change that
Everything is in balance, increase the power by increasing the engine you also increase the weight and in turn reduce the agility of the car.
Rip out all the "unnecessary" ancillaries, lose the sound system, lighten the car as a whole you will get some of that agility back but lose comfort.

 

[B21]

In relation to the 2l being more nimble than the 3l... remember that's inevitable and no amount of fiddling will change that
Everything is in balance, increase the power by increasing the engine you also increase the weight and in turn reduce the agility of the car.
Rip out all the "unnecessary" ancillaries, lose the sound system, lighten the car as a whole you will get some of that agility back but lose comfort.

Yes you’re so right, sadly…my main weight loss program will be me…if I get down to a respectable weight I can add a cappuccino machine back in :rofl:

Now that I’ve been told I’m a crap driver I’ve resigned myself to ‘point and squirt’ :tumbleweed: :driving: :rofl:

Just wonder what squirts I’m going to stamp on :tumbleweed: :rofl:

Still I’m enjoying playing with all sorts of toys that sadly were not a available for the N20 ZF8HP version…

Interesting if expensive to conduct such experiments..still just as well I didn’t like the G29..I could have spent yet more money and still be twiddling :rofl:

Even as it is trying to absently minded overtake reminds that there was a reason Audi deployed 3 Torsen diffs on their cars.. :driving: :driving: :driving:

 

[The.Analyst]

The coils you are looking are they these?

https://nexsysmotorsport.com/n54-ignition-coil-upgrade-kit-stock-or-vtt-valve-cover/

I looked at these a while back but heard some reliability and quality issues

https://precisionraceworks.com/products/n54-ignition-kit

Do you need to re-gap the plugs?

Separately, after your trip what’s your view on Ohlins versus Bilstein given the cost difference?

 

[B21]

The coils you are looking are they these?

https://nexsysmotorsport.com/n54-ignition-coil-upgrade-kit-stock-or-vtt-valve-cover/

I looked at these a while back but heard some reliability and quality issues

https://precisionraceworks.com/products/n54-ignition-kit

Do you need to re-gap the plugs?

Separately, after your trip what’s your view on Ohlins versus Bilstein given the cost difference?

Hi Tony,

Yes the nexy ones I've ordered..its just the bracket and connectors, you have to buy your own B58 coils, I've gone with Eldor as they rated them the best.

I looked at the precision race works stuff but a few horror stories and the B58 coils seem to be a later /better technology.

Gap wise hoping with all that shock n awe that the plug gaps could stay close to stock even with bigger turbos and more boost!

Hard to say on Ohlins vs Bilsteins taking costs into account.

The Ohlins have FAB build quality and are fully adjustable, if a bit of faff to wind up the preload and damping..I think damping can be done without wheels off..will look when its dryer and warmer.

I think some Bilsteins would work well, they did on my N20.

 

[B21]

Just booked in my 437Ms to be done in gloss black with laquer at these boys..early January

Been referred to them by by tech guy.

Anyone used them, seen their work?

https://www.pentlandpowdercoating.co.uk ... rbishment/

 

[peeblezZ4]

Just booked in my 437Ms to be done in gloss black with laquer at these boys..early January

Been referred to them by by tech guy.

Anyone used them, seen their work?

https://www.pentlandpowdercoating.co.uk ... rbishment/

The guys recommended to me by my local bodyshop man (Who I rate very highly) are Wheel Pro at Corstorphine. He'd recommend them to any really fussy clients/jobs over anyone else in the area. Although I didn't get around to getting my 326's refurbished, Wheelpro quoted me £280 for 4 x 19 inch wheels in October. http://www.wheelproscotland.co.uk/ I've used Pentland before and would rate them as 'ok'. They turn over a load of wheels..

 

[B21]

Just booked in my 437Ms to be done in gloss black with laquer at these boys..early January

Been referred to them by by tech guy.

Anyone used them, seen their work?

https://www.pentlandpowdercoating.co.uk ... rbishment/

The guys recommended to me by my local bodyshop man (Who I rate very highly) are Wheel Pro at Corstorphine. He'd recommend them to any really fussy clients/jobs over anyone else in the area. Although I didn't get around to getting my 326's refurbished, Wheelpro quoted me £280 for 4 x 19 inch wheels in October. http://www.wheelproscotland.co.uk/ I've used Pentland before and would rate them as 'ok'. They turn over a load of wheels..

Stuart noted, I’ll give them a call tomorrow

Update..booked in with Wheel Pro…3rd January .gloss black and clear lacquer £320 drop of car then pick up.. :driving:

 

[B21]

As trailed, UPS delivered my B58 ignition coil adapter kit along with a set of Eldor aka BMW B58 ignition coils..

The benefit of this set up is that compared to a stock N54 coil set up, the energy fired into the plugs is over 100% more, the spark duration is over 50% more and the peak voltage is 10k volts more or about 25%.

What it means is that when pushing more charge into the cylinders, as associated with a re-map / big turbos etc the charge will be ignited more vigorously than with the stock set up.

Even with new plugs n coils it’s standard practice to reduce the spark plug gap from 30 thou to 22 thou to try and get a reliable spark at higher rpm / charge levels.

The kit uses a lovely anodised bracket to forcibly hold the coils down on the plugs to ensure they don’t ‘pop off’.

Also the kit includes adapter harnesses to map the B58 coil pins to the N54 wiring.

Final part is some longer reach rubber HT connectors to replace the B58 connectors as they are not long enough to reach into the N54 plug wells.

MHD provides an option for the increased dwell time that is associated with charging the coils up to fire.

This is all done with overdriving the ECU output circuits that provide the energy to the coils.

The Eldor variants rated slightly better than the Bosch versions.

Another advantage relative to custom coils is that if a coil fails then it’s a standard OE part.

 

[B21]

Here’s a table showing relative performance of various coil set up for the N54 with PR being the incumbent supplier of hot poop ignition systems and R8 being a popular ‘bodge’ using Audi based coils and adapters..

 

[stevespg]

of all the suspension changes youve made , which would you say are those that are most significant and those that are much less noticeable?

my 35I is definitely in a "touring" category vs my z4m, but i'd not want to lose the comfort of the e89 suspension ......it'd be nice if it were less likely to roll on bends, but not sure if i need to start on stiffer roll bars or elsewhere

 

[B21]

of all the suspension changes youve made , which would you say are those that are most significant and those that are much less noticeable?

my 35I is definitely in a "touring" category vs my z4m, but i'd not want to lose the comfort of the e89 suspension ......it'd be nice if it were less likely to roll on bends, but not sure if i need to start on stiffer roll bars or elsewhere

It’s a complex answer..

First of all with all the mods I’ve done the car is better riding, more comfortable and less noisy than a stock 35is…

The design aims were not to make a track oriented car but one that you could sit in for 7-8 hours, 5 days in a row whilst pressing on at a pace that some would fine challenging, whilst coping with a possible 500 BHP and 700nm of torque.

To answer your points..replacing the run flats and the adaptive suspension are the maximum impact for cost.

Then M3 steering arms.

Then steering linkage top bearing.

Then ARBs.

Wider wheels with wider tyres are nice but it’s a performance thing.

Of course if you want to boot a 35i then a LSD is really a must..the e-diff just shuts things down rather than letting you tramp on. But it’s not a comfort thing, it’s a performance thing. :driving:

Hope that helps?

 

[stevespg]

thank you, yes, the answer is most useful.
Runflats are already gone - which made a big difference on 19's. Mine is on stock suspension, not adaptive, but even so, a set of more competent shocks would seem the next step... albeit quite a cost at approx 2k from my initial brief search!

thank you

 

[B21]

thank you, yes, the answer is most useful.
Runflats are already gone - which made a big difference on 19's. Mine is on stock suspension, not adaptive, but even so, a set of more competent shocks would seem the next step... albeit quite a cost at approx 2k from my initial brief search!

thank you

Yes I found runflats either in 19 nor 18 were great…especially after fitting M3 linkages and bushes.

I run Bilstein B8 shocks with MSport springs on my 20i auto E89 and was very pleased with the results…

Some B8s with Supplex springs would be a cost effective alternative IMHO

KWs don’t seem to be rated for street biased performance with comfort.

 

[B21]

Like a hamster I’m accumulating various parts that have been known to fail / require replacement at some time.

Taking advantage of special offers and deep discounts to aquire these as , yet again, I plan to keep this car for a long long time.

So got a high pressure fuel pump as a Christmas present…it’s the final revision of the HPFP dated 2012.

There were 7 revisions before they stopped N54 development and support.

Looks like most 35i / 35is Z4s escaped the early failures..so any E89 35 post 2011 should have the final HPFP.

My car is a 2011 and given it’s a keepers and I’ll be asking the HPFP to deliver nearly 80% more fuel than originally tasked with, so we’ll see how the item copes..if not a swap out.

 

[sars]

My car is a 2011 and given it’s a keepers and I’ll be asking the HPFP to deliver nearly 80% more fuel than originally tasked with, so we’ll see how the item copes..if not a swap out.

That was an excellent Christmas present
Not a criticism, just genuinely intrigued, how do you figure that it will have to deliver 80% more fuel? Even if you increase power to 600 BHP with bigger turbo's, that won't necessarily require 80% more fuel to be burned. Also how will you deliver 80% more fuel to each cylinder and how will you keep everything cool after you've done so?
As a wise Chief Engineer once said, ye cannae change the laws of physics

 

[B21]

My car is a 2011 and given it’s a keepers and I’ll be asking the HPFP to deliver nearly 80% more fuel than originally tasked with, so we’ll see how the item copes..if not a swap out.

That was an excellent Christmas present
Not a criticism, just genuinely intrigued, how do you figure that it will have to deliver 80% more fuel? Even if you increase power to 600 BHP with bigger turbo's, that won't necessarily require 80% more fuel to be burned. Also how will you deliver 80% more fuel to each cylinder and how will you keep everything cool after you've done so?
As a wise Chief Engineer once said, ye cannae change the laws of physics

Good questions..

So if we assume at max BHP rpm we need x amount of fuel (however you measure it, firkins per lunar month?)

We ‘know’ that as you tweak turbo cars you need to richen the mixture primarily to avoid the risk of going lean where things will melt in a heartbeat and to provide extra cooling.

So say BMW at peak BHP used a 13.5 to 1 ratio we will be around 12.5 ratio or richer..so we are already burning 9% more fuel just for safety..

If we go for say 500 BHP at the rear wheels with our big turbos then we are around 570-600 BHP crank..

So 570/335 = 70% more fuel assuming similar burn conditions but we are needing at least 9% more for ‘safety’.

So we are at 79% ish more fuel required.

And..we really really don’t want sagging fuel pressure at 550bhp + in our little N54 or it’s Good Night Vienna..

Cooling wise I’m accepting that the use of such BHP is transitory in nature so relying on existing mass to absorb the heat and then let it dissipate as I re-enter from hyperspace..

The other empirical issue is that there are many who have gone further and their engines have survived seemingly unmarked.

On a more practical note the tuning process for theses set ups starts benign and slowly iterates to higher powers over several runs.

The data logging which is very comprehensive on the N54 will show trend data well before the ‘bang’ or ‘sizzle’ assuming you use an A grade tuning organisation that have tread this path many times before.

One of my personal reasons of choosing the 35i N54 is that there are many many folks that have tweaked these engines (past 1000bhp crank) so there is a huge body of empirical experience ..unlike my forays with my baby N20.

 

[Nanu]

of all the suspension changes youve made , which would you say are those that are most significant and those that are much less noticeable?

my 35I is definitely in a "touring" category vs my z4m, but i'd not want to lose the comfort of the e89 suspension ......it'd be nice if it were less likely to roll on bends, but not sure if i need to start on stiffer roll bars or elsewhere

thank you, yes, the answer is most useful.
Runflats are already gone - which made a big difference on 19's. Mine is on stock suspension, not adaptive, but even so, a set of more competent shocks would seem the next step... albeit quite a cost at approx 2k from my initial brief search!
thank you

There is a lot of opinions re run flats and non run flats. The 35IS has adaptive suspension and my Indy reckons that the adaptive suspension is better with run flats? 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?

 

[Smartbear]

of all the suspension changes youve made , which would you say are those that are most significant and those that are much less noticeable?

my 35I is definitely in a "touring" category vs my z4m, but i'd not want to lose the comfort of the e89 suspension ......it'd be nice if it were less likely to roll on bends, but not sure if i need to start on stiffer roll bars or elsewhere

thank you, yes, the answer is most useful.
Runflats are already gone - which made a big difference on 19's. Mine is on stock suspension, not adaptive, but even so, a set of more competent shocks would seem the next step... albeit quite a cost at approx 2k from my initial brief search!
thank you

There is a lot of opinions re run flats and non run flats. The 35IS has adaptive suspension and my Indy reckons that the adaptive suspension is better with run flats? 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’ve only heard good things from those that have chosen non runflat tyres, there must be several 35is owners on here running normal tyres :?
Rob

 

[Nanu]

Not due to change for at least another 15 - 20K but when I do, will have to change all four corners, so if I do change from run flats, that would be the time to do it. The more opinions I can get from fellow 35is owners the better. Gladly no hurry though.

 

[B21]

of all the suspension changes youve made , which would you say are those that are most significant and those that are much less noticeable?

my 35I is definitely in a "touring" category vs my z4m, but i'd not want to lose the comfort of the e89 suspension ......it'd be nice if it were less likely to roll on bends, but not sure if i need to start on stiffer roll bars or elsewhere

thank you, yes, the answer is most useful.
Runflats are already gone - which made a big difference on 19's. Mine is on stock suspension, not adaptive, but even so, a set of more competent shocks would seem the next step... albeit quite a cost at approx 2k from my initial brief search!
thank you

There is a lot of opinions re run flats and non run flats. The 35IS has adaptive suspension and my Indy reckons that the adaptive suspension is better with run flats? 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?

It’s a good question…the ride and the handling are a composite of all the parts in the whole chassis, suspension, tyre systems.

Also what one person appears to be ‘good handling’ can be perceived by another as ‘poor’

From my perspective I’ve tried the following combinations…

19” 326m with OE runflats on 20i MSport
17” 103 with Chinese rubber on 20i MSport
17” 103 with Conti TS830 winter tyres 20i MSport
17” Pro Race 1.2 with Conti Sports 3 on 20i MSport
17” Pro Race 1.2 with Goodyear Vectra 4 Seasons MSport
18” Zito 935 with Conti Sports 5 on 20i MSport
18” Zito 935 with Goodyear Assy 5 on 20i MSport
18” 325M with OE runflats on 20i MSport
18” 325m with OE runflats on 35is
18” Zito 935 with Goodyear Assy 5 on 35is
19” 437M with Michelin PS4S on 35is

There have been changes to the MSport with Bilstein B8s and M3 linkages, uprated ARBs which have now been repeated with Ohlins, M3 linkages and uprated ARBs on the 35is.

What I haven’t tried is the later generations of run flats.


My personal view for my style of driving (and I know I’m not a very good driver) is..

19” with runflats very poor ride and poor handling on the 20i

18” with runflats poor ride and poor handling on the 20i and 35is

All 17” wheels and tyres gave a good ride with Contis being fabulous, handling was best on 18” Contis and Bilstein B8 on 20i.

18” Goodyear ok ride ok handling on 35is with adaptive suspension

19” PS4S and Ohlins great ride and handling on 35is

What I did notice is that fitting the 18” runflats to the 20i with M3 steering linkages was much worse as more road vibration got transmitted through the steering.

So that’s the conclusion for me over 35,000 miles of Zedding..