Scottish Borders
The BMW N54 was fitted with two Mitsubishi low pressure (8 PSI boost) TD03 turbochargers.
Cylinders 1-3 and 4-6 each blew exhaust gases through a relatively small turbo..the air from a common airbox was ducted to each turbo individually, then the compressed air was merged into a single duct before going through a single forward mounted intercooler before entering the inlet ports via a single charge pipe.
TD03 refers to the 'frame' size..ie how large the overall castings were that house the turbine and compressor parts..TD03 being small..a BMW N20 engine has a sigle TD04 turbine.
The logic of two turbo chargers was to reduce throttle lag and allow quick spool (up) of the turbos through small turbines and compressors having low mass.
Not much puff was asked for (8 PSI boost) to take and engine that would have made about 250 bhp without boost to 335 (35is) with boost.
In my case at 60k miles I took my turbos of to replace them with two new TTE500 'hybrid' turbos.
They are called hybrid because they are a frankenstein turbo..that is the overall unit is made from an orginal new Mitsubishi BMW N54 turbo, but the turbine wheel, compressor wheel and other parts are designed and supplied by others..
Sadly after 2 years and 20k miles the rear TTE turbo developed an oil leak..there was a leak form the external oil feed caused by the Indy in Darlington not fitting it correctly..(cocked over and nipped the o ring)..but after fixing that more oil came out of the turbo itself..you can see the burnt oil on the clamp that connects the hot section to the cold section.
On examination it has a lot of lateral play and some longtitude play in the bearing..so much so that the turbine plates are hitting the main structure!
After looking at various options I was only really left with one..send it back to TTE in Germany..essentially not repairable by any UK turbo overhaul house due to specific TTE parts.
The distributor said they had sold over 8,000 and only had 20 duff ones..must be unlucky..Indy confirmed all oil feed lines were OK..heh ho..
Now having the orginal 60k mile originals I've decided to get them upgraded as there's a £1,200 saving if you have the luxury/time to send good units back..mine look in really good condition apart from some play in the waste gate hinge..which is a well known weak spot on the stock turbos.
So 2 boxes via Fedex to Germany..1 TTE500 to be refurbed and 2 old OE ones to be converted to TTE spec..at least I shouldn't be off the road for a prolongued period with those as back up..1st world problems..
The pics show the two sets of turbos..you can see that a TTE turbo takes the stock Mitsubishi part new and starts from there.
You can see the bigger turbine wheel and whilst not intially obvious, the compressor wheel is bigger and also has a 50mm outlet vs 47 mm ish OE oulet..turbine speed is up from around 120k to closer to 200k..hence more boost (I'm hitting 21.5 psi peak) but more wear..
We will see what gives..
Cylinders 1-3 and 4-6 each blew exhaust gases through a relatively small turbo..the air from a common airbox was ducted to each turbo individually, then the compressed air was merged into a single duct before going through a single forward mounted intercooler before entering the inlet ports via a single charge pipe.
TD03 refers to the 'frame' size..ie how large the overall castings were that house the turbine and compressor parts..TD03 being small..a BMW N20 engine has a sigle TD04 turbine.
The logic of two turbo chargers was to reduce throttle lag and allow quick spool (up) of the turbos through small turbines and compressors having low mass.
Not much puff was asked for (8 PSI boost) to take and engine that would have made about 250 bhp without boost to 335 (35is) with boost.
In my case at 60k miles I took my turbos of to replace them with two new TTE500 'hybrid' turbos.
They are called hybrid because they are a frankenstein turbo..that is the overall unit is made from an orginal new Mitsubishi BMW N54 turbo, but the turbine wheel, compressor wheel and other parts are designed and supplied by others..
Sadly after 2 years and 20k miles the rear TTE turbo developed an oil leak..there was a leak form the external oil feed caused by the Indy in Darlington not fitting it correctly..(cocked over and nipped the o ring)..but after fixing that more oil came out of the turbo itself..you can see the burnt oil on the clamp that connects the hot section to the cold section.
On examination it has a lot of lateral play and some longtitude play in the bearing..so much so that the turbine plates are hitting the main structure!
After looking at various options I was only really left with one..send it back to TTE in Germany..essentially not repairable by any UK turbo overhaul house due to specific TTE parts.
The distributor said they had sold over 8,000 and only had 20 duff ones..must be unlucky..Indy confirmed all oil feed lines were OK..heh ho..
Now having the orginal 60k mile originals I've decided to get them upgraded as there's a £1,200 saving if you have the luxury/time to send good units back..mine look in really good condition apart from some play in the waste gate hinge..which is a well known weak spot on the stock turbos.
So 2 boxes via Fedex to Germany..1 TTE500 to be refurbed and 2 old OE ones to be converted to TTE spec..at least I shouldn't be off the road for a prolongued period with those as back up..1st world problems..
The pics show the two sets of turbos..you can see that a TTE turbo takes the stock Mitsubishi part new and starts from there.
You can see the bigger turbine wheel and whilst not intially obvious, the compressor wheel is bigger and also has a 50mm outlet vs 47 mm ish OE oulet..turbine speed is up from around 120k to closer to 200k..hence more boost (I'm hitting 21.5 psi peak) but more wear..
We will see what gives..
