[johny]

My turbo's are starting to fail on me, they barely hold boost and they aren't as strong as they used to be .I want to swap my twins with 2 twin-scroll one's from the n55 i don't know if this is possible but i would love to keep on using oem equipment when i mod my e90.I looked for this topic and i did a little bit of research but i did not find much answers. I would like to know more about what you gear heads think and more about this topic. Thanks for the input !

[n54gte]

No.

[AK 335i]

yes please

[crypticc]

Won't the twin scroll be designed for flow from the exhaust of six cylinders? Not two lots of three?

[spectacula]

Originally Posted by crypticc

Won't the twin scroll be designed for flow from the exhaust of six cylinders? Not two lots of three?

x2

[Ovitrix335]

I found a n55 turbo with manifold for dirt cheap, it only has 3k miles and was wondering if i can swap the n54 stockers with the n55 turbo setup. I don't know if the car can be tuned with that n55 setup on a n54.... I haven't seen anyone attempting this....

[Rob@RBTurbo]

You could likely put the N55 complete turbofold on the N54 engine from a hardware perspective with some minor alterations, extra parts, and ingenuity. On the performance front it would be a step in the wrong direction though IMO, and that is not considering the O2 signal muddling that would occur as well (which is why the Vishnu ST has O2s pre turbo to work on the N54). At the end of the day just not a good idea that would end up with a loss of performance, extra cost in more parts, and tuning issues because of the O2s and also likely boost control.

Rob

[Ovitrix335]

It would've been interesting if you can control boost. Thanks for the info Rob..

[johny]

Originally Posted by Rob@RBTurbo

You could likely put the N55 complete turbofold on the N54 engine from a hardware perspective with some minor alterations, extra parts, and ingenuity. On the performance front it would be a step in the wrong direction though IMO, and that is not considering the O2 signal muddling that would occur as well (which is why the Vishnu ST has O2s pre turbo to work on the N54). At the end of the day just not a good idea that would end up with a loss of performance, extra cost in more parts, and tuning issues because of the O2s and also likely boost control.

Rob

i was trying to figure out this whole prob with the o2's in the n55 and the way they were placed .. but you made it much clearer thanks again rob

[Streetluger06]

What about cutting the stock turbos off of the N54 manifolds and do the same for the n55 stockers (two sets). When weld the N55 turbos to the N54 manifolds with a small reducer to match the different openings?

It would be a big pain if the N55 turbos use different oil and water connections. I assume the waste gates would be ok.

Probably better off with RB's or stage 2's for simplicity.

[roadkillrob]

There are a whole load of things you would have to change more than just the turbos and manifold - like others have mentioned, the oil lines, down pipe, the N55 also routes all the intake lines completely different and airbox is totally different, so would be way more money to replace all the required parts and then the DME probably won't control the wastegate or DVs correctly as there is only one wastegate! Just never going to happen!

[johny]

Thanks for the your thoughts and input guys . Much appreciated !

[Rob@RBTurbo]

This has been a question for years now. Simply put, it is very difficult working on this car even with turbos that are a perfect fit. The room just is not there to do much of anything. The OEM manifold outlet placement is too close to the block, and trying to use them for anything other than the OEM turbos is just way too much of a hassle to consider making everything else fit. A train wreck, if you will. With enough thousands of dollars into custom adapters, spacers, grinding, etc, could work with the right turbo, but at the end of the day best bet is to just get something already available or get a new full blown setup including everything that has proper fitment as designed. Fitment is critical IMO, the ST kits seem to fit VERY well from what I've seen.

Originally Posted by Streetluger06

What about cutting the stock turbos off of the N54 manifolds and do the same for the n55 stockers (two sets). When weld the N55 turbos to the N54 manifolds with a small reducer to match the different openings?

It would be a big pain if the N55 turbos use different oil and water connections. I assume the waste gates would be ok.

Probably better off with RB's or stage 2's for simplicity.

Anything can happen, but it is the amount of dollars, time, and headaches it takes to get there that counts. At the end of the day, it is just a bad idea. Get new OEM turbos or some other option if you feel they will not make you enough power.

Originally Posted by roadkillrob

Just never going to happen!