[OTO335i]

Hello Guys and Gals,

I wanted to start a thread were people could ask questions without really feeling stupid. I got this idea from the Audizine forum that I used to be part of and it was pretty successful. This could help reduce the amount of new threads that are started just to have a question answered that some of us may find to be a "stupid" question.

I'll start with mine,

This is regarding the HPFP's in some of our cars as well as all HPFP's in most direct injection equipped vehicles.

Would anyone know what exactly fails in our HPFP's and if anyone has ever tackled to open their pump to see what the failure component would be? Why couldn't BMW just have a high pressure fuel pump located straight from the gas tank instead of having a low pressure pump that goes into the high pressure pump?

Why do GDI engines need this much pressure in the first place? I've read that the reason for direct injection is for better combustion which leads to better fuel economy and the potential for more power but then you end up with carbon build up which causes your valves to stick and giving you poor fuel consumption... I don't know about most of you but I grew up driving cars produced in the 90's which were mostly port injection and the fuel consumption from these vehicles were just as good as today's cars. Even with all these sensors and gadgets to help with fuel consumption I don't find that newer cars really have better fuel mileage.

Of course this is my opinion on the matter but I'm comparing my old 94 integra gsr to my gf's 2016 Elantra and the fuel consumption was better on my integra that I owned a while back.

Anyways, I hope this thread can help control the amount of new threads started and we can all come to one place for answers.

Cheers

[Welcome to NBA Jam]

What's the best oil?

nobody answer this question

[galahad05]

Originally Posted by Welcome to NBA Jam

What's the best oil?

nobody answer this question

The stuff with Liquid Moly in it.

(I am nobody)

[Pladi]

Originally Posted by OTO335i

Why couldn't BMW just have a high pressure fuel pump located straight from the gas tank instead of having a low pressure pump that goes into the high pressure pump?

Cheers

First off nice idea for the thread. I can sort of answer only on of your questions since i owned a HPFP car before: Mazdapssed 3 and got quite involved in the platform where i ended up rebuilding the engine.

The answer to that question lies at the struggle to create that amount of pressure. To create 2000+ PSI is quite a task with electric pumps. So for reliability BMW and MANY other manufacturers use the camshaft speed to drive the pump. ITs very clever idea. Since CAM shaft is linear to RPM then the cam driven pump can deliver different pressures locked to the speed of the cam. Doing it with one pump ads alot more challenges. Fuel lines and safety too.

[OTO335i]

Originally Posted by Pladi

First off nice idea for the thread. I can sort of answer only on of your questions since i owned a HPFP car before: Mazdapssed 3 and got quite involved in the platform where i ended up rebuilding the engine.

The answer to that question lies at the struggle to create that amount of pressure. To create 2000+ PSI is quite a task with electric pumps. So for reliability BMW and MANY other manufacturers use the camshaft speed to drive the pump. ITs very clever idea. Since CAM shaft is linear to RPM then the cam driven pump can deliver different pressures locked to the speed of the cam. Doing it with one pump ads alot more challenges. Fuel lines and safety too.

Thanks man, ok so our HPFP is indeed mechanically driven which would explain why it is mounted where it is, the sensors on it are only for readings on the pressure it puts out.

Thanks for your input, that clarifies some of the questions I had.

[Pladi]

Originally Posted by OTO335i

Thanks man, ok so our HPFP is indeed mechanically driven which would explain why it is mounted where it is, the sensors on it are only for readings on the pressure it puts out.

Thanks for your input, that clarifies some of the questions I had.

Yes its mechanically driven. Why it fails so much that i dont know. For the mazdaspeed we would upgrade the internals with a different spring rate to produce more pressure reliably. We used VAG internals. That was cable of 500 HP plus.

[Pladi]

Here is my stupid question: Can you lift the rear end of a E90 using the differential as a lift point ? That way you can lift the entire rear end with one point. Does this hurt the car in any way ?

[OTO335i]

Originally Posted by Pladi

Here is my stupid question: Can you lift the rear end of a E90 using the differential as a lift point ? That way you can lift the entire rear end with one point. Does this hurt the car in any way ?

Yes you can lift it by the differential, the best practice would probably be to insert a piece of wood in-between your jack and diff but I've done it plenty of times without and never had an issue, just seat your jack slowly on the diff and you should be good.

[mecheng77]

I believe the other reason for Direct Injection is better fuel atomization which also leads to better power.

[desertman123]

Originally Posted by Welcome to NBA Jam

What's the best oil?

nobody answer this question

Genuine best answer no one can dispute: BMW approved LL-01 oil.

Dont dispute this.

[cahme]

Originally Posted by OTO335i

I don't know about most of you but I grew up driving cars produced in the 90's which were mostly port injection and the fuel consumption from these vehicles were just as good as today's cars. Even with all these sensors and gadgets to help with fuel consumption I don't find that newer cars really have better fuel mileage.

Of course this is my opinion on the matter but I'm comparing my old 94 integra gsr to my gf's 2016 Elantra and the fuel consumption was better on my integra that I owned a while back.
Cheers

If you want to compare DI vs PI Google up on N52 vs N53.
I've put some miles on my DD n55 335 (modded) and dedicated time in the past months with an N52 si Z4 in my day to day commute and theyve gotten almost the exact same gas mileage.

[OTO335i]

Originally Posted by cahme

If you want to compare DI vs PI Google up onn N52 vs N53.
I've put some miles on my DD n55 335 (modded) and dedicated time in the past months with an N52 si Z4 in my day to day commute and theyve gotten almost the exact same gas mileage.

I'll take a look, thanks for the info! So your N52 that is port injected gets the same mileage as your N55 that is direct injection. That's pretty much we're I'm try to get at with these car manufactures stating that direct injection is better. I don't agree with that as your valves will eventually build up carbon and then you end up with valves sticking and causing poor fuel consumption..

[cahme]

My 335 is a 2011 with an N55 and 158k miles. I bought it at 113k mi 2 1/2 years ago. I pulled the intake and cleaned the valves a week or two after I bought it as the PO (60k - 113k) told me he never checked. It wasn't nearly as bad as some N54s I've seen pics of and I don't plan on redoing it until 200k.

[OTO335i]

Originally Posted by cahme

My 335 is a 2011 with an N55 and 158k miles. I bought it at 113k mi 2 1/2 years ago. I pulled the intake and cleaned the valves a week or two after I bought it as the PO (60k - 113k) told me he never checked. It wasn't nearly as bad as some N54s I've seen pics of and I don't plan on redoing it until 200k.

That's something I'm going to do very soon, I can hear my valves ticking a little and sometimes I get a bit of hesitation on take off but nothing major yet. I'll be doing that and then I'm possibly going to sell, not certain yet what I want to do.

[Pladi]

Originally Posted by OTO335i

That's something I'm going to do very soon, I can hear my valves ticking a little and sometimes I get a bit of hesitation on take off but nothing major yet. I'll be doing that and then I'm possibly going to sell, not certain yet what I want to do.

On the N55 this job is not necessary. I took my intake mani for another job. (OFHG) and found that the valves were actually pretty clean. The N55 has a different design of PCV.

[OTO335i]

Originally Posted by Pladi

On the N55 this job is not necessary. I took my intake mani for another job. (OFHG) and found that the valves were actually pretty clean. The N55 has a different design of PCV.

I have an N54 in mine..

[Pladi]

Originally Posted by OTO335i

I have an N54 in mine..

oki then yes makes sense.

[BimmerNugget]

My 328i is sorta slow. Will an engine delete make my car lighter and therefore faster? Anyone try this yet?

[Pladi]

Originally Posted by BimmerNugget

My 328i is sorta slow. Will an engine delete make my car lighter and therefore faster? Anyone try this yet?

brain delete might work better..

[galahad05]

Originally Posted by BimmerNugget

My 328i is sorta slow. Will an engine delete make my car lighter and therefore faster? Anyone try this yet?

By definition yes. That engine weighs hundreds of pounds!

Without it, yours will be the lightest BMW on these forums.

[Pinscher]

My wheels have chipping pain, how do i fix it?

i'd appreciate an actual answer that isn't repaint the whole wheel, or you cannot.

If there is no way to do touch up jobs on wheels, then i'm seriously disappointing in the auto industry.

[Pladi]

Originally Posted by Pinscher

If there is no way to do touch up jobs on wheels, then i'm seriously disappointing in the auto industry.

Hope ur being sarcastic. They have found a way to control intake and cam timing through oil pressure and you are disappointed with the auto industry because of paint chips on your wheels ?