Z4 35is Upgraded Turbos?

S

sunnydays

Active member
Hey, hope everyone is well!

Is anyone aware of any cars / builds of Z4's in the UK with upgraded twins, IE RB or Pure Turbos? I can see very few build logs featuring upgraded twins with these cars, I can see one or two in the EU, a few in the USA and one in Germany (Ken @ Wedge Performance, single turbo). Anyone aware if any builds have been done in the UK?

Curious as to how well the chassis would handle this level of power (circa 600bhp). I can only assume the car would need an LSD to help it put the power down, even with MP4S with wider than standard tyres. Would the DCT require uprated clutch packs?
 
There's a couple of cars over on SpoolStreet with lots of work done, the consensus from people I've spoked to has been that a LSD is useful on a track car but not really worth it for a road car. I do remember seeing a UK owner with upgraded turbos but can't remember where. I know the steering column makes things a little more complicated for us.

The gearbox seems to be fine on cars producing as much as 750nm torque, I don't think you would need to consider clutch pack changes at 600bhp.
We also have the ability to flash the DCT using xHP flash which will allow it to hold even more torque so I've got no idea where the new limits are. The only people that seem to ever suffer from clutch slip are JB4 users but that's to be expected.
 
sunnydays said:
Hey, hope everyone is well!

Is anyone aware of any cars / builds of Z4's in the UK with upgraded twins, IE RB or Pure Turbos? I can see very few build logs featuring upgraded twins with these cars, I can see one or two in the EU, a few in the USA and one in Germany (Ken @ Wedge Performance, single turbo). Anyone aware if any builds have been done in the UK?

Curious as to how well the chassis would handle this level of power (circa 600bhp). I can only assume the car would need an LSD to help it put the power down, even with MP4S with wider than standard tyres. Would the DCT require uprated clutch packs?
Click to expand...
As you get up to that BHP you will face added challenges and increased unreliability from the motor. Potentially you will need the booster kit for the HPFP, this increases engine vibration and can lead to timing chanin tensioner failure, also an indirect injection kit could be a possibility.
A guy with a youtube channel called 'vehicular DIY' does pretty much everything on the N54, his current series covers engine failure after increasing HPFP performance, its not in a Z4 but its all relevant. If I was going to that power I would have my bottom end to pieces, new shells, oil pump etc.

And exactly how much faster is a 600BHP car than a 400??, not a lot. Larger turbos will remove the lower down torque as well which is one of the things I love about the N54. AND torque = accelaration NOT BHP......

Be interesting to follow the project if you go ahead though, contact the guy on youtube for tips he will answer
 
mcbutler said:
torque = accelaration NOT BHP
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VERY important point! BHP == top end speed, not acceleration. Though there is obviously a relationship between torque and BHP, but the two numbers alone dont tell the full story until you look at the curves over RPM, and use that information with some knowledge about what the two values actually mean, and how gearing ratio affects actual output, etc etc. Low-end torque is much more useful in a daily or even track cars in most cases than high end. Of course, if you just want to go 180 on the autobahn then you need some HP upgrades...
 
BadgerDog said:
mcbutler said:
torque = accelaration NOT BHP
Click to expand...

VERY important point! BHP == top end speed, not acceleration. Though there is obviously a relationship between torque and BHP, but the two numbers alone dont tell the full story until you look at the curves over RPM, and use that information with some knowledge about what the two values actually mean, and how gearing ratio affects actual output, etc etc. Low-end torque is much more useful in a daily or even track cars in most cases than high end. Of course, if you just want to go 180 on the autobahn then you need some HP upgrades...
Click to expand...
Of course, ideally BHP curves peaking as torque starts to fall is pretty much spot on for most uses, the flexibility of multiple, small, lightweigh fast spooling turbos makes for a far better road car than for instance the same car with a massive single turbo, although you could add a supercharger to take over the boost until the big heavy turbo catches up, but why add all the complexity...

Or maybe just go electric........
 
mcbutler said:
As you get up to that BHP you will face added challenges and increased unreliability from the motor. Potentially you will need the booster kit for the HPFP, this increases engine vibration and can lead to timing chanin tensioner failure, also an indirect injection kit could be a possibility.
A guy with a youtube channel called 'vehicular DIY' does pretty much everything on the N54, his current series covers engine failure after increasing HPFP performance, its not in a Z4 but its all relevant. If I was going to that power I would have my bottom end to pieces, new shells, oil pump etc.

And exactly how much faster is a 600BHP car than a 400??, not a lot. Larger turbos will remove the lower down torque as well which is one of the things I love about the N54. AND torque = accelaration NOT BHP......

Be interesting to follow the project if you go ahead though, contact the guy on youtube for tips he will answer
Click to expand...

He won't need any additional fuelling for 600bhp. The low pressure fuel pump is typically the bottleneck for the N54 but the Z4 has a better low pressure supply than other N54 equipped cars.

The VehicularDIY chap has a 2006 N54 in a 3 series with 200,000 miles so not really a good point of reference. There were quite a few revisions to engine components before our Z4s hit production.

You can expect 680bhp and 750nm from a set of hybrid turbos on 93octane fuel. Peak torque would be between 3500-3800rpm so not exactly lacking in low end punch. No need to worry about engine components if his goal is only 600bhp, that would be a low boost map for some RB GC hybrids.
 
mcbutler said:
torque = accelaration NOT BHP
Click to expand...

It’s not quite as simple as that though. An F1 car engine produces massive BHP but not a lot of torque. The modern turbo engines produce more than the old na engines but still relatively low. The accelerate very well!

It’s more about where that power & torque is in the rev range and how easy it is to access it. If you plant the throttle from 2k and the torque doesn’t kick in until 5k then obviously it’ll feel slow until that point but if you keep the revs up so you keep in in the peak torque area, it’ll fly. That’s why drag cars can get away with a big single turbo if it can be kept spinning hard.

I had a friend with an RX7 which he bought with a big single turbo kit and it was incredible in a straight line. He bought it as a track car though and it was useless on the track because he had to feather it around corners and wait for it to be pointing down the straight before he could accelerate! My MX5 with a third of the power was much quicker around every track we visited!
 
Lazza said:
mcbutler said:
torque = accelaration NOT BHP
Click to expand...

It’s not quite as simple as that though. An F1 car engine produces massive BHP but not a lot of torque. The modern turbo engines produce more than the old na engines but still relatively low. The accelerate very well!

It’s more about where that power & torque is in the rev range and how easy it is to access it. If you plant the throttle from 2k and the torque doesn’t kick in until 5k then obviously it’ll feel slow until that point but if you keep the revs up so you keep in in the peak torque area, it’ll fly. That’s why drag cars can get away with a big single turbo if it can be kept spinning hard.

I had a friend with an RX7 which he bought with a big single turbo kit and it was incredible in a straight line. He bought it as a track car though and it was useless on the track because he had to feather it around corners and wait for it to be pointing down the straight before he could accelerate! My MX5 with a third of the power was much quicker around every track we visited!
Click to expand...


https://z4-forum.com/forum/viewtopic.php?f=23&t=124112
 
Busterboo said:
BadgerDog said:
mcbutler said:
Or maybe just go electric........
Click to expand...
Sure, but where is the fun in that?! :rofl:
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You haven't driven a Tesla, then?
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I have, my brother has the dual motor sport, its incredible, you can put 4 people in with a boot full of luggage then wreck a 700BHP lambo!! He tells me he will be placing a reserve on the new tesla roadster for delivery late next year, 7500 lbft torque in basic spec with a max 600 mile range and fast charging!!! Fastest production car ever..
Best thing is you can actually buy 'exhaust systems' for them. They are fake pipes fitted with high end sound output, you can make the car sound like anything from a Z4 to an F1 car or a big old V8 dinosaur....
I would go electric tomorrow if I could afford a tesla, gas cars and the entire industry supporting it is already in slow decline and it will only get faster.
 
BadgerDog said:
mcbutler said:
Best thing is you can actually buy 'exhaust systems' for them.
Click to expand...
:rofl:

That just made my day, thank you!
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I laughed my arse off when I first heard of it, then I watched a system being fitted to a diesel dog range rover (shed). It was around £4k apparently but WOW what a sound. It links into the cars ECU and reacts to throttle demand. load etc....
 
mcbutler said:
BadgerDog said:
mcbutler said:
Best thing is you can actually buy 'exhaust systems' for them.
Click to expand...
:rofl:

That just made my day, thank you!
Click to expand...
I laughed my arse off when I first heard of it, then I watched a system being fitted to a diesel dog range rover (shed). It was around £4k apparently but WOW what a sound. It links into the cars ECU and reacts to throttle demand. load etc....
Click to expand...
I mean dont get me wrong, its kinda neat in a certain way, just so utterly silly to spend that kinda money on something so clearly superficial. But I guess if you have the money for a high end Tesla...
 
BadgerDog said:
mcbutler said:
BadgerDog said:
:rofl:

That just made my day, thank you!
Click to expand...
I laughed my arse off when I first heard of it, then I watched a system being fitted to a diesel dog range rover (shed). It was around £4k apparently but WOW what a sound. It links into the cars ECU and reacts to throttle demand. load etc....
Click to expand...
I mean dont get me wrong, its kinda neat in a certain way, just so utterly silly to spend that kinda money on something so clearly superficial. But I guess if you have the money for a high end Tesla...
Click to expand...

It’s all on a continuum....there’s been a long history of faux styling and faux noise as part of the design..BMW and others all fit fake electronic exhaust sound generators that feed the car’s main and in some cases dedicated speakers..Tesla have just taken it to the next logical step to address the emotional needs of petrol heads
 
sunnydays said:
Hey, hope everyone is well!

Is anyone aware of any cars / builds of Z4's in the UK with upgraded twins, IE RB or Pure Turbos? I can see very few build logs featuring upgraded twins with these cars, I can see one or two in the EU, a few in the USA and one in Germany (Ken @ Wedge Performance, single turbo). Anyone aware if any builds have been done in the UK?

Curious as to how well the chassis would handle this level of power (circa 600bhp). I can only assume the car would need an LSD to help it put the power down, even with MP4S with wider than standard tyres. Would the DCT require uprated clutch packs?
Click to expand...
Ive been running an MHD 2+ map and its fun but next year I will be upgrading the turbos. Nothing as stupid as going to a big single, been down that road before with Subarus many years back. Absolutely as flat as a pancake until that turbo spools then all hell brakes loose, just not a good driving experience. The twin turbo N54 in the E89 is much more refined in its power delivery. I'll be looking at upgrading the turbos to give me around 600bhp as I am aware the DCT is ok upto that level, though I didnt know the LPFP can also deliver enough fuel to create that kind of power. I'm in 2 minds about the LSD, I dont intend tracking the car so I may fit the turbos first and then see how it feels. So Sunny, what are you plans?
 
stijohnny said:
sunnydays said:
Hey, hope everyone is well!

Is anyone aware of any cars / builds of Z4's in the UK with upgraded twins, IE RB or Pure Turbos? I can see very few build logs featuring upgraded twins with these cars, I can see one or two in the EU, a few in the USA and one in Germany (Ken @ Wedge Performance, single turbo). Anyone aware if any builds have been done in the UK?

Curious as to how well the chassis would handle this level of power (circa 600bhp). I can only assume the car would need an LSD to help it put the power down, even with MP4S with wider than standard tyres. Would the DCT require uprated clutch packs?
Click to expand...
Ive been running an MHD 2+ map and its fun but next year I will be upgrading the turbos. Nothing as stupid as going to a big single, been down that road before with Subarus many years back. Absolutely as flat as a pancake until that turbo spools then all hell brakes loose, just not a good driving experience. The twin turbo N54 in the E89 is much more refined in its power delivery. I'll be looking at upgrading the turbos to give me around 600bhp as I am aware the DCT is ok upto that level, though I didnt know the LPFP can also deliver enough fuel to create that kind of power. I'm in 2 minds about the LSD, I dont intend tracking the car so I may fit the turbos first and then see how it feels. So Sunny, what are you plans?
Click to expand...

My next steps are deciding whether I should buy my old car back or not to go down this route. Thanks all for the info certainly something to think about
 
Had a really good think about this guys and it is definitely something that I will be doing. I will create a new thread in the upcoming months once I procure a car for this :thumbsup:
 
Hold off on committing to any tuner for the project just yet. I'm in the final steps of a true fix for the N54 boost ceiling issue, I've got it running on a couple of cars already and it looks to be a success, it greatly improves the performance of the shifts vs the current solutions from MHD and any other tuner. Currently all DCT cars boosting above 18.5PSI utilise some sort of bodge either with a JB4 or by entering incorrect scaling values for the pressure sensor to trick the car into thinking it's producing less boost than it is which causes issues.

It involved a small rewrite of the program area of the ECU so it requires more caution when testing than normal remaps which only alter calibration. I've got another person testing it this weekend but I've been running my car at about 20PSI for the last couple of months and it's been solid.
 
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