N47 turbo upgrade

[GeorgeKLT]

Hi,

From past experiences that you have had with N47 engine, what turbo would get me to 260hp(including here intercooler, fuel pump, injectors, clutch upgrades).

My car is a e90 318d with 143hp stock(current mods are 335 intercooler, N57 fuel pump, N57 injectors, kevlar clutch)

I have made a hybrid out of car's turbo(Garrett GT1749V ) but according to local tuning shops it won't get me past 220-230hp.
Specs of hybrid turbo:
Inducer 38.5/exducer 52 intake
Inducer 43/exducer 38 exhaust

Also what other modifications are neded to install bigger turbo?


Thank you.

 

[obi_waynne]

Hope this helps,

Garrett GTB2260Vk will flow to around 300bhp but power won't come on as quickly and you'll hit full boost around 2800rpm
Garrett GTB2056Vk is generally good for around 250 with full boost at 2700rpm

The stock GT1749C will usually top out around 200 bhp and full boost is hit at 1900rpm so it's a fast spooling turbo with quite a wide power band.

I'm guessing you've used the GTB1752 VRK internals on this which peak power 2200rpm and has a 220bhp top end.

But don't chase a headline power figure, the overall torque band and power band is what matters most in daily driving. Big power turbos usually have quite a bit of lag, so be prepared to accept this.

You are going to hit traction issues at these power levels, so a good differential will be a good idea.

Fuel upgrades are likely with the injectors and pump topping out.

 

[GeorgeKLT]

Thank you for your extensive response!

To be honest, I'm not sure what internals were used for the upgrade.
Boost is now at 1.9 bar
Inducer 38.5/exducer 52 intake
Inducer 43/exducer 38 exhaust

Tuner said we can push the car at around 230hp. I'm thinking how much hp would be gain from a downpipe installation.
15-20hp would be wishful thinking?

Any idea on what needs to be modified in order to install GTB2056VZK on N47 engine?

I have searched the internet but only found this on a German forum:
"Just in case that my turbo says goodbye ....
Which turbo would you recommend for an N47?
and the reply
GTB2056VZK
But that is anything but plug and play, as the loader has a V-band connection. That would still be my favorite. Large exhaust housing, ball bearings and therefore good responsiveness. Used in the current BMW models."

 

[obi_waynne]

You would need a custom manifold for starters, I'm sure some of the pipe work will get in the way and need moving around. Personally if I can't fit a hybrid turbo (stock casing, revised internals) I don't bother because of all the work involved unless you can buy a kit or find someone to fabricate what you need. Have a chat with the guys over at Darkside, they might be able to point you in the direction of some parts.

At those boost levels you'll be risking detonation so lowering the compression ratio is a good idea to get more headroom.

A downpipe installation won't net you 15hp sadly.

What fuel are you mapping for? Set it for 100 or 109 octane and you'll see a power boost, but you'll only be able to use that fuel type.

Water injection might help you use more boost.

Have you considered stroking the engine and pushing up the displacement slightly?

 

[GeorgeKLT]

I will speak with a local tuning shop about fitting a gtb2056vzk turbo in my engine(N47)

unable to go down the 100 or 109 octane route since it's a diesel (for the record, I usually use premium diesel fuel, higher cetane number)

"Water injection might help you use more boost." - sounds good, will read more about this

I will try and get the best out of my hybrid turbo by installing a downpipe and see the hp outcome.

If the results are not what I expect, I will install a bigger turbo, probably gtb2056vzk

It's a daily driver so I hope turbo lag won't be a deal breaker on the bigger turbo.

 

[obi_waynne]

I like your style, keep adding more power till your happy!

Ooops - diesel sorry, yes of course it is, having a mental block there. You can get higher cetane fuel but it's not going to make as much difference as it would on a petrol. My mind was clearly elsewhere for that sentence!

It will be interesting to see a twin charged diesel setup - this is me just giving you ideas and hoping we get to read an interesting project thread.

Let us know how you get on, I know a lot of guys will be interested to hear what you do and how you get on with this project.

 

[GeorgeKLT]

I will keep you posted with my endeavors.

Currently, I'm waiting on the injectors. They are being delivered from abroad so hopefully in another 1-2 weeks I will have them installed.

Quick question regarding downpipe size. For the stock exhaust, should I go with 2.5" or 3" ? I'm all about the hp gains so if you guys say 3" then that will be it.

Engine is a 2.0 litre, turbo boost will be 1.9 bar

 

[thexav]

A 2.5 will actually flow faster than a 3 and it will weight less. The 3 will sound better though, deeper and more growly depending on your silencer choice of course.