BMW 335i N54-N55 ?
Discussion
The engines have different engine covers. The N55 engine cover says 'Twinpower Turbo'. The N54 says nothing. Remember not to confuse 'Twinpower turbo' with twin turbo, as some have done in the past. The N55 is a twin scroll single turbo, whereby exhaust gasses are fed into the exhaust housing via two different scrolls, or channels within the housing, so that the pulses from each cylinder bank do not interfere with each other and create unwanted turbulence. The N54 was a normal twin turbo with two small Mitsubishi TD03 turbos. The peak torque of the N55 arrives 100 rpm earlier than that of the N54. Otherwise rated peak torque and horsepower are the same. Fuel efficiency goes to the N55, but only marginally. Tuneability to the N54.
The N54 purportedly had fully forged internals, meaning crank, rods and pistons, whereas the N55 has just the forged crank with hypereutectic pistons. Therefore theoretically the N54 is a more robust engine, but each will differ so take that how you will. An abused N54 will still blow up quicker than a well treated N55!
The N54 has piezoelectric injectors which are very clever and precise (and noisy), but prone to failure and expensive to replace. Most engines will have had theirs replaced under recall so it shouldn't be an issue. The N55 uses a normal solenoid injector so shouldn't be so problematic. Both engines tend to need coilpack replacements at some stage, but you could say the same of any engine. Waterpumps are a guaranteed failure on either. Beware any car with 60,000 miles that hasn't had it done. High pressure fuel pumps die on earlier cars but as with injectors many will have had theirs replaced (at least once) along with a software upgrade under recall. Identify this by listening for the hum of the LPFP priming the HPFP when you unlock the car after it has been sitting for a while.
Watch for oil filter housing gaskets leaking, cam cover gaskets leaking, and vacuum lines leaking. Of course, there is also the dreaded wastegate rattle on the N54s too - with the car in neutral, rev the engine to 3,000 rpm and let the revs fall away. If you hear a clattering from the engine as the revs fall back to idle, best walk away unless you have a spare 3K for replacement! Again though, many will have had their turbos replaced under recall.
All told, both are good engines. You will enjoy driving either!
The N54 purportedly had fully forged internals, meaning crank, rods and pistons, whereas the N55 has just the forged crank with hypereutectic pistons. Therefore theoretically the N54 is a more robust engine, but each will differ so take that how you will. An abused N54 will still blow up quicker than a well treated N55!
The N54 has piezoelectric injectors which are very clever and precise (and noisy), but prone to failure and expensive to replace. Most engines will have had theirs replaced under recall so it shouldn't be an issue. The N55 uses a normal solenoid injector so shouldn't be so problematic. Both engines tend to need coilpack replacements at some stage, but you could say the same of any engine. Waterpumps are a guaranteed failure on either. Beware any car with 60,000 miles that hasn't had it done. High pressure fuel pumps die on earlier cars but as with injectors many will have had theirs replaced (at least once) along with a software upgrade under recall. Identify this by listening for the hum of the LPFP priming the HPFP when you unlock the car after it has been sitting for a while.
Watch for oil filter housing gaskets leaking, cam cover gaskets leaking, and vacuum lines leaking. Of course, there is also the dreaded wastegate rattle on the N54s too - with the car in neutral, rev the engine to 3,000 rpm and let the revs fall away. If you hear a clattering from the engine as the revs fall back to idle, best walk away unless you have a spare 3K for replacement! Again though, many will have had their turbos replaced under recall.
All told, both are good engines. You will enjoy driving either!
Thanks again Rdawson
so after 7 years of being on the dark side of diesel I have come back to the fold
I had forgotten how responsive petrol is and just how much more feel the BMW has over the Audi A5 3lt TDi this car is a joy to drive can not wait to pick her up ,of course the Audi threw a wobbly when it realised it was being part exed the MOT had run out and it decided its steering rack was going to go south , so got to get that sorted before I pick the BMW up
Thanks everyone for your help
Here she is , Lemans blue 36,000 mils
so after 7 years of being on the dark side of diesel I have come back to the fold
I had forgotten how responsive petrol is and just how much more feel the BMW has over the Audi A5 3lt TDi this car is a joy to drive can not wait to pick her up ,of course the Audi threw a wobbly when it realised it was being part exed the MOT had run out and it decided its steering rack was going to go south , so got to get that sorted before I pick the BMW up
Thanks everyone for your help
Here she is , Lemans blue 36,000 mils
Edited by Lost soul on Friday 10th April 07:31
You say walk away if it has the wastegate rattle?
I say walk closer.
Use it as a bargaining chip to get more money knocked off, then for £140 (£40 monthly cost and £100 excess) get them fixed under BMW warranty.
Mine's got the wastegate rattle (as have most N54s) and apart from the noise it's not an issue until it starts triggering low boost codes, at which point it will go to BMW and I will get the turbos done for the above £140.
I say walk closer.
Use it as a bargaining chip to get more money knocked off, then for £140 (£40 monthly cost and £100 excess) get them fixed under BMW warranty.
Mine's got the wastegate rattle (as have most N54s) and apart from the noise it's not an issue until it starts triggering low boost codes, at which point it will go to BMW and I will get the turbos done for the above £140.
Rdawson said:
The N54 purportedly had fully forged internals, meaning crank, rods and pistons, whereas the N55 has just the forged crank with hypereutectic pistons.
First I've heard of the N55 having a forged crank, everything I've read on the N55 infers that it has a cast crank.....?Also, pretty sure from reading lots of stuff on this that the N54 doesn't have forged pistons either...just forged, crank and rods.....??
Lost soul said:
Thanks again Rdawson
so after 7 years of being on the dark side of diesel I have come back to the fold
I had forgotten how responsive petrol is and just how much more feel the BMW has over the Audi A5 3lt TDi this car is a joy to drive can not wait to pick her up ,of course the Audi threw a wobbly when it realised it was being part exed the MOT had run out and it decided its steering rack was going to go south , so got to get that sorted before I pick the BMW up
Thanks everyone for your help
Here she is , Lemans blue 36,000 mils
Bloody 'ell, it looks exactly like mine... Apart from the wheels.
Dave
so after 7 years of being on the dark side of diesel I have come back to the fold
I had forgotten how responsive petrol is and just how much more feel the BMW has over the Audi A5 3lt TDi this car is a joy to drive can not wait to pick her up ,of course the Audi threw a wobbly when it realised it was being part exed the MOT had run out and it decided its steering rack was going to go south , so got to get that sorted before I pick the BMW up
Thanks everyone for your help
Here she is , Lemans blue 36,000 mils
Bloody 'ell, it looks exactly like mine... Apart from the wheels.
Dave
Edited by Lost soul on Friday 10th April 07:31
Early N54s have forged pistons. You can tell whether yours does by entering your VIN into real oem and working through the engine block components. I can look up the code when I have a chance. Based on BMW training manuals both turbo N engines have a steel crank.
aeropilot said:
First I've heard of the N55 having a forged crank, everything I've read on the N55 infers that it has a cast crank.....?
Also, pretty sure from reading lots of stuff on this that the N54 doesn't have forged pistons either...just forged, crank and rods.....??
Also, pretty sure from reading lots of stuff on this that the N54 doesn't have forged pistons either...just forged, crank and rods.....??
Dunno, maybe. But if it's a pre-existing fault would the warranty company not decline the claim? I'm no expert on car warranties but hey if it works then why not.
Dannbodge said:
You say walk away if it has the wastegate rattle?
I say walk closer.
Use it as a bargaining chip to get more money knocked off, then for £140 (£40 monthly cost and £100 excess) get them fixed under BMW warranty.
Mine's got the wastegate rattle (as have most N54s) and apart from the noise it's not an issue until it starts triggering low boost codes, at which point it will go to BMW and I will get the turbos done for the above £140.
I say walk closer.
Use it as a bargaining chip to get more money knocked off, then for £140 (£40 monthly cost and £100 excess) get them fixed under BMW warranty.
Mine's got the wastegate rattle (as have most N54s) and apart from the noise it's not an issue until it starts triggering low boost codes, at which point it will go to BMW and I will get the turbos done for the above £140.
DVandrews said:
Lost soul said:
Thanks again Rdawson
so after 7 years of being on the dark side of diesel I have come back to the fold
I had forgotten how responsive petrol is and just how much more feel the BMW has over the Audi A5 3lt TDi this car is a joy to drive can not wait to pick her up ,of course the Audi threw a wobbly when it realised it was being part exed the MOT had run out and it decided its steering rack was going to go south , so got to get that sorted before I pick the BMW up
Thanks everyone for your help
Here she is , Lemans blue 36,000 mils
Bloody 'ell, it looks exactly like mine... Apart from the wheels.so after 7 years of being on the dark side of diesel I have come back to the fold
I had forgotten how responsive petrol is and just how much more feel the BMW has over the Audi A5 3lt TDi this car is a joy to drive can not wait to pick her up ,of course the Audi threw a wobbly when it realised it was being part exed the MOT had run out and it decided its steering rack was going to go south , so got to get that sorted before I pick the BMW up
Thanks everyone for your help
Here she is , Lemans blue 36,000 mils
Dave
Well It is a lovely colour last owner had monster problems with cracking wheels I do like them I think they set the car off and compliment the colour
Gassing Station | BMW General | Top of Page | What's New | My Stuff