400bhp 35i 0-60?

G

George.E89

Member
 Kent
Hi 👋

I have the z4 35i with DCT and want to get it to 400bhp, a stage 2 I have had a quote for includes the following :

- Wagner EVO 2 Intercooler
- Supersprint Decat Downpipes
- Direnza Induction Kit
- Stage 2 Engine Tune
- Stage 3 XHP Gearbox Flash

Will this get it to 400bhp, and if you have a Z4 35i DCT with 400bhp, what’s your 0-60?

Also is the invoice quote attached reasonable, I haven’t tuned a car before so am unaware?

This is a secondary question, but I have also chosen to add the following to the invoice of the tuner in order to retain a good reliability, please let me know if you’d recommend anything else to help with reliability, or let me know if I don’t need quite so much :

- Alloy Chargepipe
- Gearbox Service
- Diff Oil Change
- Upgraded Oil Cooler (Single)
- Brake Fluid (Mobul RBF 6000) & Coolant Flush
- NGK 95770 Spark Plugs
- Fresh Coil Packs
- 5W-40 Oil Change & Filter
 

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All sounds great but the cost! My thoughts are that’s an awful lot of money that you will never get back and will possibly devalue the car.
You probably won’t see a huge 0-60 difference. Why not just go stage 1 for a tenth of the cost?
Plus will it still be road legal or pass mot with the decat?
 
0-60 really is only of any consequence at the bar.
It's a lot of money to spend if you are only trying to attain a figure for kudos.
If you want a better car on the road then do a milder tune and spend the rest on suspension and brakes.
 
Having looked many times at doing similar with my previous 35is, my thoughts are:

Downpipes are overpriced IMO. Stage 2 ECU and stage 3 XHP can be done much cheaper via the MHD and XHP apps. Intercooler is the right price for the EVO2, but surely the EVO1 at £400 would be plenty?

Would agree with the posts above, just do a stage one with MHD, get 360-370 bhp and it'll cost about £200 (I can't remember the exact prices). Paying £4,500 more for an extra 30-40 bhp doesn't seem like value for money to me. At that point you might as well go a bit further and upgrade the turbo instead - or save the money and use it for chassis improvements like a good set Bilstein dampers and an LSD. That's where I would have put £4,500 (or probably less) into my 35is, and kept with the Stage 1 map.

The coil and plug replacements are very sensible, if you don't do those you'll probably have to soon after tuning anyway. I'm not sure the oil cooler or chargepipe are necessary, but I'm guessing not crazy expensive and good for peace of mind.
 
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So as others have said..you can get to around 380bhp with not much effort the final 20 takes a lot more cost

Before you start

Have a walnut blast on the intakes
Full service with decent oil and filters
Fresh decent coils n plugs
Run and check what error codes you have

MHD stage 1 or 1+ will get you 380 ish on 99 octane fuel cheaper and almost certainly better

MHD stage 2 ish
Wagner 5.5 inch FMIC
De-cat downpipes (will still pass UK MOT)

Gearbox service good idea come what may
xHP does a great update to the DCT box

Send money for the other bits to me..
 
B21

Thread 'Atacama Yellow 35is build thread'

I thought (this time) I'd document the changes and mods I'm doing to this virginal 2011 model year 35is which came pretty fully loaded with options.

Judging by the notorious tail lights this example has spent most of its life garaged. (no water born damage)

The car appeared in Auto Trader, then here and then, ironically for me, in a local garage in my old folks home town.

It had just done under 50k miles, and just been 'serviced' by an indy by the previous owner.

The price I paid was way,way,way more than WBAC suggested pricing but way way below the original listed price.

If you have...
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Thank you for everyone’s responses, it does make sense actually that 360bhp approximately can be achieved for a 1/10 the price of 400bhp

I think I will go with an MHD stage 1, xHP Gearbox flash 3, both done myself, then gearbox service and change of plugs and packs
 
B21 said:
So as others have said..you can get to around 380bhp with not much effort the final 20 takes a lot more cost

Before you start

Have a walnut blast on the intakes
Full service with decent oil and filters
Fresh decent coils n plugs
Run and check what error codes you have

MHD stage 1 or 1+ will get you 380 ish on 99 octane fuel cheaper and almost certainly better

MHD stage 2 ish
Wagner 5.5 inch FMIC
De-cat downpipes (will still pass UK MOT)

Gearbox service good idea come what may
xHP does a great update to the DCT box

Send money for the other bits to me..
Click to expand...
Would you say walnut blasting is required if I only do the MHD stage 1 and then an xHP flash, also is stage 3 xHP reasonable for me to do do you think
 
George.E89 said:
Thank you for everyone’s responses, it does make sense actually that 360bhp approximately can be achieved for a 1/10 the price of 400bhp

I think I will go with an MHD stage 1, xHP Gearbox flash 3, both done myself, then gearbox service and change of plugs and packs
Click to expand...
Stage 2 is all you need at that power on xHP..stage 3c just creates extra wear n tear
 
George.E89 said:
Would you say walnut blasting is required if I only do the MHD stage 1 and then an xHP flash, also is stage 3 xHP reasonable for me to do do you think
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Most n54s need a walnut blast just to keep stock power..

Waste of time fiddling with the rest when the basics aren’t spot on…
 
Personally I wouldn’t bother with the Wagner intercooler, my 35is came with one with a 365bhp tune, my 35i has around 380bhp without and there’s no difference in temps between the two, both pull like trains too so i doubt you’ll see anything in better boost breathing.

400 is way too much if you’re not doing some decent chassis/suspension work, again my 35i is pretty lethal on standard stuff, downright dangerous actually and that’s with almost new OEM springs and shocks. So I’ve put KW coil overs on, H&R front and rear anti roll bars + adjustable drop links all round, M3 control arms, adjustable castor arms, various stiffer bushes, and bang for buck the anti roll,bars are the best mod, had them on the stock 35is with its adaptive shocks/OEM springs and they made an incredible difference, so purely imho these are a must.

As said I think the last 20bhp is not worth bothering with, 380 it’ll be plenty, too much really but….better to spend it on chassis mods to reign the grunt in on what’s a jelly car in stock form.
 
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Advice given to me by Birds BMW on walnut blasting was don't waste your money unless you have a reason to believe there is carbon build up that needs dealing with.
 
tiglon said:
Advice given to me by Birds BMW on walnut blasting was don't waste your money unless you have a reason to believe there is carbon build up that needs dealing with.
Click to expand...

My car went from 327 BHP on the same dyno to 347 stock courtesy of just a walnut clean..no other changes then onto

Seems counter intuitive that one of the biggest documented issues with the n54 is not addressed before you ask for more air to be blown in over that crap…

FWIW Bird’s tunes got overtaken by mhd sometime ago..

Even my tuning guys in Sunderland who are gurus in tuning N54s had to acknowledge that mhd v10 out of the box did a great job..

Of course a hand crafted tune..given enough dyno time should do better than an OTS tune.

But you can see how hard mhd v10 pushes the hardware that they’ve not left much on the table..

 
B21 said:
My car went from 327 BHP on the same dyno to 347 stock courtesy of just a walnut clean..no other changes then onto

Seems counter intuitive that one of the biggest documented issues with the n54 is not addressed before you ask for more air to be blown in over that crap…

FWIW Bird’s tunes got overtaken by mhd sometime ago..

Even my tuning guys in Sunderland who are gurus in tuning N54s had to acknowledge that mhd v10 out of the box did a great job..

Of course a hand crafted tune..given enough dyno time should do better than an OTS tune.

But you can see how hard mhd v10 pushes the hardware that they’ve not left much on the table..

Click to expand...

I'm not saying Birds do the best N54 tunes (to be honest I don't think they have any interest in that as the UK market for N54 tuning has been tiny for many years) but that has no relevance to whether a walnut blast is necessary/beneficial. The reason for sharing is that they know the engine very well, and for me their advice is useful - we all trust different sources.

Very happy to agree with you that MHD do great maps for the N54, I'd recommend wholeheartedly and will use again if I ever have another engine that they offer maps for. I still have the app on my phone just in case I accidentally buy another orange 35is...

Your engine being full of carbon deposits doesn't mean that all other N54s will be. They've all been driven and maintained differently. I'd be curious whether yours has needed or benefitted from a second walnut blast after a few years of using the engine more enthusiastically than the previous owner?

Personally I'd do a dyno run first and only shell out for a walnut blast if the power is well down as yours was. Madness to just assume you've got a problem with absolutely no symptoms at all - would you buy a new boiler just because your neighbours' broke down, despite your own heating working perfectly well?

As always, other opinions are available. I'm no expert.
 
tiglon said:
Advice given to me by Birds BMW on walnut blasting was don't waste your money unless you have a reason to believe there is carbon build up that needs dealing with.
Click to expand...
A couple of photos of mine at 64000 miles
Before and after walnut blasting
 

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Chippie said:
A couple of photos of mine at 64000 miles
Before and after walnut blasting
Click to expand...

I've never said no N54 will ever need walnut blasting. I'm well aware that some do, I just wouldn't assume that they all do. As per my post above, they've all been driven and maintained differently.
 
I think it’s just the design of the direct injection engine and the breather/recirculation systems that cause the issue and personally I’d say all N54’s will suffer from carbon buildup.
 
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Chippie said:
I think it’s just the design of the direct injection engine and the breather/recirculation systems that cause the issue and personally I’d say all N54’s will suffer from carbon buildup.
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Possibly, eventually. Some may benefit from it at 40k miles, others might be fine until 140k miles. I wouldn't just assume if I bought one that it needed walnut blasting right now, just like I wouldn't immediately replace the water pump, tyres, brakes, HPFP, rocker cover gasket etc etc just because they'll need doing eventually.

All just opinion though, isn't it?
 
FWIW there was no indication that a walnut clean was required and ..sadly I’ve lost the pics taken by the guys, but the level of contamination was less than Chippie’s

If you think of the lengths folks go to ensure good gas flow on NA heads then if you’re looking to tune a N54 then its logical to get everything tickety boo before you start the tuning process..rather thsn just relying on brute force to blow air past that crap ..

As you may know I’ve spent many hours on that dyno having beaten most things to death..

As to when its required ..

I think catch cans are largely a placebo

Stop / start and short journeys are really harmful..

A good non volatile ester based oil is a major step forward

I’ll probably look at it in a couple of years I think..

I may do a bit more dyno tweaking next year..

If you’re driven by cost effectiveness then just the leave stock..

If you’re in pursuit of perfection then..
 
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