Can a bigger turbo be put on ?

[Kobus328i]

Can a bigger turbo be put on a turbo diesel BMW, say on the e46 320d or e46 330d ?

If so, what impact will it have and is it a big undertaking to do this ? What will be required, except the bigger turbo of course :rollsmile:

Thanx

 

[Rayzor]

Good question :thumbs: now we wait :fencelook:

 

[SP33DYV]

Yes Kobus, it can definitely be done, but needs to be done in conjunction with a software tune to make full use of the new turbo.

 

[P1000]

Short answer: No.

Long answer: No. Well, actually, you can, but it WILL suck. The turbo is very well matched to the flowrate of the engine, which is very critical , especially since it is a variable-AR turbo (VNT). And the range selection of VNT turbos are very limited. If you choose to go for a fixed turbo that is bigger, you might be able to increase the maximum kW, but your acceleration WILL be lower across the board. What you could conceivable do is to change the turbo on an early 330d to that of the late model (GT2556 to a GT2260). This will require a retune, but it should expand the boost region a bit, meaning that it starts boosting sooner and keeps up longer. They bolt on the exhaust side, but the intake side needs a little bit of work. Off course, if you really want an upgrade, you will have to install the twin-turbo setup off the 535d, but that is quite major work, and I don't know if the software will cope. Then you would also need to add the injectors from that car, unless you want to destroy the engine. But in the end, on that platform the peak power you can make is limited by a lot of factors - just look at the Alpina D10 e39, it had a twin-turbo setup (although, not sequential like the 535d), and it made circa 180kW only.

 

[Rayzor]

What about a twin scroll turbo? would that work?

 

[P1000]

What about a twin scroll turbo? would that work?

No, that is much lower in the food chain than a VNT turbo. All the setups I described above use VNT turbos, regardless of number of turbos. The reason you need at least a VNT turbo is because you need a LOT of boost over a very wide rev range, and that simply cannot be done without VNT. If it was cost effective to use VNT turbos on petrol cars, the good ones would all have it. The only petrol car I know that use VNT turbos is the Porsche 911, but they use Inconnel to make the VNT mechanism to withstand the higher exhaust gas temperatures from petrol.

 

[SP33DYV]

Thanks for proving me wrong P1000. :rollsmile:

 

[XMAX]

This is an interesting topic...


I have heard of Seat Cupras or Leons that have diesels motors with larger turbos and make loads more power than the stock setup.


there was also talk of having a larger compressor housing with the same size boost pipes. How would that affect the car.

 

[DieselFan]

^I think you're talking about a hybrid turbo, seems fairly more common with the 120d. Not sure about the e46 but with the E90 its easier to do with the older garret turbos for whatever reason they switched to the Mitsubishi maybe they got a better deal? And from my understanding it is harder to do and if it all possible it has to be done when the turbo is brand new... from what I've read from various forums. Rolf did however say that it is possible to use the garret turbo in place of the Mitsubishi. One could expect around 250hp with sw + dp and hybrid turbo (again from what I've read).

I think the e46 also uses a garret turbo, there are hybrid turbos you can buy for them also the 330d. HybridTurbos

Around R15 000. But to have 185kw in a 320d you could give many gti's and st's a good hiding.

 

[netercol]

i think its more a question of why would you want to.. (or need to)

in simple terms, power and torque on a diesel is limited by exhaust gas temp (egt)
on a petrol engine, lean mixture (more air than fuel) means hotter EGT, on a diesel lean mixtures (more air than fuel ) means cooler EGT..

so you can keeping pouring in the diesel in (size of injector and injection timing,quantity ect plays a role ofc), but you reach a limit where the richer mixture will drive egt pass the absolute safe limit of around 850 deg celcius..
things start melting, engine damage is a matter of time..

you need more air.. you need to get more air into the engine to lower egt's. bigger intercoolers, bigger hybrid turbo's..

like p1000 said, some combinations are posible, some are not..

on my own e46 330d im busy experimenting with a hybrid, but results have been rather predictable..
having fitted a larger compressor, mass airflow is up, but because of this generation turbo's already high emp (exhaust manifold pressure) , forcing more air in the intake side without changing the turbine side has actually made the car slower , since what goes in must come out, and the engine is chokeing on it higher exhaust emp..

 

[CliftonH]

Guess in turbo bigger is not always better. Lol. :biglol:

 

[Kobus328i]

Thank you for all the feedback guys. :thumbs:

It was just something I was pondering reading about various power upgrades.

 

[spawn616]

go youtube holset bmw, arnt many diesel vids,maybe one or two,but many petrol,



p1000 and netercol are the diesel boffs,but if u have lots and lots of money anything is possible.....