[Tr1ppy]

So I ran my car on the dyno over the weekend. Its a 2008 330i with the N53 engine (272PS).

Being an 8 year old car and with 65k miles I was expecting around 255-260bhp from the original 268.
The best it did was 234bhp!!!

Can anyone please guide me in the direction of getting that 34bhp back?

I have had suggestions such as a service including spark plugs and air filter, and also performing the Terraclean service (they now do an intake service!).
But will these minor changes get me 34bhp back?

What do people think are the common causes of loss of power on the N53 engine?

I understand they are DI engines so the intake may be coked so has anyone stripped down the intake and give it a good clean? Also thinking about blanking off the EGR but would this cause problems later?


Apologies for the amount of questions, and I understand that power loss issues are open ended but any guidance is much appreciated.

Thanks.

[BMW-330i]

I've just replaced my IAT (same as a MAF but different for Euro cars) and it's make a huge difference. I also replaced the K&N induction filter added by the previous owner as I really don't feel this was helping to keep my engine clean. I have an N52 engine.

Have you tested the diagnostics?

[Stoatmaster]

Originally Posted by Tr1ppy

So I ran my car on the dyno over the weekend. Its a 2008 330i with the N53 engine (272PS).

Being an 8 year old car and with 65k miles I was expecting around 255-260bhp from the original 268.
The best it did was 234bhp!!!

Was that measured at the wheels or flywheel? If at the wheels, I'd expect that to be not too far off.

[Tr1ppy]

Well they told me it adjusted for the flywheel. A number of N/A cars lost power that day including a E92 M3 that got around 370bhp (should be 414bhp).

Thanks I've checked the diagnostics with my Carly app and nothing has come up. Car is running fine it just feels a little bit sluggish overall. I think it may need a damn good intake clean as well as Terraclean for the injectors.

Does anyone know of any guides on how to remove the inlet manifold for N53 engine? Or I guess other similar engines such as N52 may do.

[Phil325i]

Suggest you search for a DIY guide on HPFP replacement, as that will involve inlet manifold removal...

[Tr1ppy]

Originally Posted by Phil325i

Suggest you search for a DIY guide on HPFP replacement, as that will involve inlet manifold removal...

Ah right thanks, will look for that! 😀

[Dann]

If suggest getting it dynod elsewhere.
Their rollers may just be out

[Not a Diesel!!!]

RS4's drop a lot of power due to Carbon build up. That's well documented due to Di.

I had my intakes walnut blasted at 66k the build up was bad but not as bad as pics I have seen for 335i.

I had the injectors done after that on warranty. Car now runs very well. That's not to say it ran that bad before. Most noticeable sign of poor running was a black exhaust pipe & slight fluctuation on idle. Showing the car was running very rich. Post the work I can now drive a couple of hundred miles with no build up. Before that it was 2-3 miles.

So have a look at your pipe & maybe spark plugs.... old school way to decide how well your engine is running.

[Not a Diesel!!!]

Originally Posted by Dann

If suggest getting it dynod elsewhere.
Their rollers may just be out

But agree with this also if other were making proportionately less power.

[Somerset Jim]

Funnily enough to I watched this clip this morning. It may help.

[Tr1ppy]

Originally Posted by Dann

If suggest getting it dynod elsewhere.
Their rollers may just be out

Thanks, someone else suggested that when I was there so I may do that but I have noticed that the car has been a little sluggish since last September. I also think its got slower due to me changing tyre profile but this may be placebo.
I went up a profile size on the rears from 255/30 to 255/35 and switched to non-RFT to protect the rims.

Originally Posted by Not a Diesel!!!

RS4's drop a lot of power due to Carbon build up. That's well documented due to Di.

I had my intakes walnut blasted at 66k the build up was bad but not as bad as pics I have seen for 335i.

I had the injectors done after that on warranty. Car now runs very well. That's not to say it ran that bad before. Most noticeable sign of poor running was a black exhaust pipe & slight fluctuation on idle. Showing the car was running very rich. Post the work I can now drive a couple of hundred miles with no build up. Before that it was 2-3 miles.

So have a look at your pipe & maybe spark plugs.... old school way to decide how well your engine is running.

Yes my tips are quite black but I thought this was normal for a DI. The injectors were replaced under warranty in 2010.

An oil service as well as spark plug change is on the cards. The plugs have never been changed (as far as I know) since 2010 when the car was on 25k miles, it is now on 65k.

I may also do a Terraclean service as they do a seperate intake clean alongside the usual injector/cylinder clean.

[Tr1ppy]

Originally Posted by Somerset Jim

Funnily enough to I watched this clip this morning. It may help.

Brilliant video, thanks! Yeah I'll be doing a full service plus Terraclean so hopefully that will bring back a lot of the power.

I'm not sure about the Redex though, some ppl say it does more harm than good, so I always put VPower in anyway.

[Not a Diesel!!!]

I got the "all exhausts are black" on Di cars story also.

But mine now once cleaned do not blacken.

I think the extra confusion is most other Di cars are turbo rather than N/A. Turbo cars are a different story they tend to run rich to compensate for the turbo.

So not may other N/A Di cars to compare ...... and not many 330i N53's either.

[Not a Diesel!!!]

Back in my university days ( pre Di) I did my final year project on Fuel Detergents. Back in the day these were basically non-volatile organics that stayed as liquid rather than vapour. They therefore coated back of inlet valve and mobilised any deposits into combustion chamber & stopped them crudding (technical term) up back of inlet valves

Di is a tricky beast as the fuel comes straight into chamber so detergents have less opportunity for cleaning. Really only injectors. And on Di these need to be super precise.

...... boy that takes me back. See Chemistry is fun.

[SID2GO]

Have you got the issue sorted yet?

[Tr1ppy]

Originally Posted by SID2GO

Have you got the issue sorted yet?

Not paid much attention to it lately as I've been enjoying the car anyway even with the ~30hp loss

I had a full service with spark plugs changed and it didnt feel much better. Also had terraclean and intake clean done, still not much change.

I haven't got any codes coming up and the engine is running fine, with a bit of a shaky idle when cold.

I'm going to cut to the chase and go for a walnut blast in a few months anyway. I'm repeatedly told that this is the only way to clean a DI engine as most of the carbon buildup will on the intake valves and port area.

[marc l]

I have a e93 325i with a n53 fitted. I'm planning to put it on a rolling road in the next month or so at Surrey Rolling Road. Mine had 218 bhp when new I'll post up results. If you have shaking when cold (like me) it will prop be a failed injector and that could obviously affect performance

[SID2GO]

Originally Posted by Tr1ppy

Not paid much attention to it lately as I've been enjoying the car anyway even with the ~30hp loss

I had a full service with spark plugs changed and it didnt feel much better. Also had terraclean and intake clean done, still not much change.

I haven't got any codes coming up and the engine is running fine, with a bit of a shaky idle when cold.

I'm going to cut to the chase and go for a walnut blast in a few months anyway. I'm repeatedly told that this is the only way to clean a DI engine as most of the carbon buildup will on the intake valves and port area.

Ah cool, I dont notice much of the cold shaking with mine but I had mine on the dyno and it was also making 230bhp. I did the AFR and it shows a slight drop after 4750rpm. I just changed my spark plugs today but they all seem to look in good health.

Also do you monitor your nox cat using carly? have you done a run to burn off the sulphur that is stored in the cat?

[SID2GO]

issue on my car is sorted. had all 6 injectors replaced. old ones are all rev 11. no strange puffs of white smoke and mpg has gone up to 45mpg on motorway cruise

[Phil325i]

Sad to hear that revision 11 injectors are failing in the same old way...

[SID2GO]

Originally Posted by Phil325i

Sad to hear that revision 11 injectors are failing in the same old way...

could have been caused by the nox. read it somewhere where that they had the nox cat and sensor sorted but then later on the injectors needed doing.

condition of the old injectors are dirty and coked up on the tips, no injector cleaner will save it unless you remove and clean them yourself

[Dormermike]

Originally Posted by Phil325i

Sad to hear that revision 11 injectors are failing in the same old way...

Indeed. They do work an awful lot harder than normal injectors as there are multiple squirts during stratified mode... personally I'd switch off stratified mode if it was possible.