[Curt2000]

I ran a search and came up with one result a few months back about possibly porting stock turbos.

The concept is to take off of the stock snails, port and polish the housings, port the wastegate, possibly upgrade the impeller and return the turbos to the car for increased performance.

Before I graduated college I was a member of the SRT-4 community and this practice was common because it was very cheap, it netted real results, and it offered a mild turbo upgrade for people who didn’t want to go with bigger setups. Companies worked on a core exchange basis so customers didn’t have any down time while the porting was being performed. The price was around $300 bucks if I remember correctly and it allowed the turbo to be able to handle more boost which resulted in +20 to 30 HP.

I believe that the N54 would respond favorably to such modification and I'm wondering what company is planning on offering this?

[bucktown]

even having them flow matched and extrude honed would be great. but methinks getting them off the side of the engine might be a pain in the ass....

[Sniz]

Originally Posted by bucktown

even having them flow matched and extrude honed would be great. but methinks getting them off the side of the engine might be a pain in the ass....

+1

access to them is a real bitch.

I had some porting done on the turbo in my S60R. It did make a difference and was reasonable in cost. If you could swap out impellers and port the stock twins on the 335 for $1,000 or so......there would be people standing in line.

[mwahlert]

still need software to take advantage of the available flow.

[Curt2000]

No doubt install would be a pain but less of a pain if your swapping stock turbos in and out in comparrison to an aftermarket setup that would require a new manifold/DP/wastegate/vacume lines...What flange do our stock turbos use btw?

[retrodrive]

when BMW swaps out the turbos at their dealerships, it is an engine-out procedure.

[ArmyBimmerDude]

Originally Posted by retrodrive

when BMW swaps out the turbos at their dealerships, it is an engine-out procedure.

+1

[Curt2000]

If people are taking off their DPs in their garages you can take off the turbos as well (I'd recommend a lift though)..just need the right collection of extensions and joints for your socket wrench

[335i4u2nv]

Originally Posted by Curt2000

If people are taking off their DPs in their garages you can take off the turbos as well (I'd recommend a lift though)..just need the right collection of extensions and joints for your socket wrench

true dat!

[retrodrive]

Ask CEA3 (Charlie). he would know for sure...I have seen him work

[scalbert]

Originally Posted by retrodrive

when BMW swaps out the turbos at their dealerships, it is an engine-out procedure.

Not always, and this was at a dealer.

You have to lower the engine some but not remove it.

[scalbert]

Originally Posted by Curt2000

If people are taking off their DPs in their garages you can take off the turbos as well (I'd recommend a lift though)..just need the right collection of extensions and joints for your socket wrench

I suspect both turbo's could be pulled in a few hours. We had the DP's off in less than one hour while on ramps and stands in my garage. Turbos would be more difficult as the subframe would need to be lowered some and supported. But isn't that what blocks of wood are for.

[Curt2000]

Are the stock manifolds log or turbular?

[scalbert]

Originally Posted by Curt2000

Are the stock manifolds log or turbular?

Semi-tubular. They are a three into one arrangement but of course, not equal lengths.

[Curt2000]

Reguardless, we could port the inlet on the cartridges and upgrade the impeller...this would result in good gains without having to touch a single bolt on the manifolds or downpipes...engine managment becomes an issue though because you would be changing the compressor maps...I'm sure its not out of Vishnu or Procede's reach though.

[Slow335i]

I don't know about you guys, but these turbos are just too damn small to take off and mess around with, almost just not worth it. Upgrade.

[Curt2000]

Upgrade the cartridges!!! someone figure out if this can be done...can we put a 14b or 16g compressor and compressor housing (cold side) on the stock turbine housing/manifold?

[Curt2000]

Alright here is an example for everyone…

Here is a picture of one of our stock turbos…the part that is circled will detach from the rest of the assembly

Once its off it will look something like this (this is actually a TDO4 cartridge off of a SRT-4)


Now lets take a look at what a set of stock TDO4’s look like


Now lets look at a TDO4 that has been ported/polished/coated and equipped with a new impeller

Before the new impeller is installed…


Now lets look at what work can be done on a stock log style exhaust manifold….
BEFORE

AFTER
(note: they have changed the flange to accommodate a larger O2 housing/downpipe)

How much does this radically ported manifold and heavily modified stock turbo set up cost???

$425 plus a $100 refundable core charge…and shipping…

This is a drop in replacement that is reliable, undetectable unless BMW wants to pull out the turbos and CHEAP….but most of all it will defiantly net some respectable gains on the N54

[Duke]

This looks like it can be done. will the engine need to be modified as far as compression goes to accommodate the higher boost levels?

and btw great post curt!

[Sparky66]

WHOA.....Please tell me they're not cracks at the wastegate actuator ...

[Curt2000]

Originally Posted by Sparky66

WHOA.....Please tell me they're not cracks at the wastegate actuator ...

Those cracks are inherent in all the SRT manifolds due to defects in the casting grain structure, the porting just makes them more aparent. So yes most SRTs have cracks around their wastegate!

[Curt2000]

Originally Posted by Duke

This looks like it can be done. will the engine need to be modified as far as compression goes to accommodate the higher boost levels?

and btw great post curt!

The stock internals should be able to hold the upped boost, there will be a increase in mass flow due to the porting but I think the fuel system and electronic managment are the critical paths in this undertaking. I havn't read much about how much the fuel system can support...which is good and bad I guess, because it means noone has suffered failure but noone has ran enough boost to be able to put a limiting number on how much boost we should run.