E89 Z4 dual lpfp in-tank?
- Thread starter fmorelli
- Start date
E20 is the best in terms of longevity of the engine and clean logs.
93 is a lot cheaper here than e85 atm and I get over double the miles out of a tank even when I mix to e20.
I can easily make way more power on e85 but I hate it for many reasons which I won't get into.
The car makes enough power and tries to hump every tree and light pole when you bury your foot to the floor.
The gearbox is the weakest link too and my diff will need a rebuild soon as is starting to faintly whine and pinion gear seal is starting to weep.
When I get a set of pirrelli trofeo r eventually when they become available, I might take it up to e40 which should see the car make close to 700rwhp
But I'm happy with the way things are and it's a handful as is, so no need for more at this stage.
93 is a lot cheaper here than e85 atm and I get over double the miles out of a tank even when I mix to e20.
I can easily make way more power on e85 but I hate it for many reasons which I won't get into.
The car makes enough power and tries to hump every tree and light pole when you bury your foot to the floor.
The gearbox is the weakest link too and my diff will need a rebuild soon as is starting to faintly whine and pinion gear seal is starting to weep.
When I get a set of pirrelli trofeo r eventually when they become available, I might take it up to e40 which should see the car make close to 700rwhp
But I'm happy with the way things are and it's a handful as is, so no need for more at this stage.
I love the idea of an e20 or e30 I just hate doing it so much. The moving from pump to pump annoys me so much.
Its easy carry a 10 litre e85 can and add it to 1/3 of a tank of e20 and top it off with 93.
Always around e20
So just to clarify, it is not necessary to run an inline filter with the z4 pump setup. Lol please pardon me, I do alot alone and I'm trying to map it all out 
its a good idea to run one but not really necessary as there is an in tank one just line the 135i's isn't there ?
I run one just for the piece of mind its there if needed.
I run one just for the piece of mind its there if needed.
Z4 has an in-tank filter and pressure regulator combo (p/n 16117168284). Working the Z4 tank is a PITA - you have to drop exhaust and shields, empty the fuel tanks (best as you can) and bottom-side mount (so be ready to catch fuel, even if you empty). IMHO I'd replace the in-tank filter while you are there.So just to clarify, it is not necessary to run an inline filter with the z4 pump setup. Lol please pardon me, I do alot alone and I'm trying to map it all out
May I ask why you are changing your LPFP pump? Stock Z4 pump a more capable configuration than other stock N54 cars. If you are running PI, a higher mix of ethanol (but then you are changing fuel lines as well), then you may need to move up. But unless your LPFP has a problem, on a Z4 it is a generally unnecessary upgrade on regular fuel with stock turbos (even at 19psi).
Filippo
I fortunately have access to a lift, and a few knowledgeable techs willing to help. So when the time comes those factors should aid in helping to make the job a little less stressful. Ill order the fuel filter per your advice. Thanks Flippo!
So why is a check valve needed for the LPFP sensor? In fact it leads me to wonder what the in-pump check valve is actually for? My recollection is the LPFP fires up the moment the door is actuated.
Filippo
I have yet to have my 535 installed yet but I got the bucketed set up from Precision Raceworks. I'm going to be running Pure Stage 2 HFs with PI. I'm hoping to hit 600whp on full E85 with a custom Wedge tune. The turbos still haven't been finished yet so I'm not sure when I'll have everything up and running. But the 535 should be plug and play.
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If you have a lpfp sensor and it doesn't see pressure or very low pressure it could throw a code (speculating and not tested)
Also having pressure at start up will make starting the car easier.
For a few dollars there is no reason not to run one.
Got it. Makes sense.
LPFP kicks on at least at LK15. So isn't there full pressure all the time at start?
Honestly not a question of money - that's an arbitrary assumption. I was trying to understand the purpose of the check valve anywhere in the system prior to the HPFP (currently in the LPFP, internally). I don't understand its function given the LPFP is turned on and pressurizes the line prior to engine start. Studying the 525/535 spec sheets, it seems that in-pump check valve really has a significant impact on flow. Assuming they are basically the same pump, but one without the check valve.
On a car that was designed where everything went hot at the same time, I would quickly understand how a check valve plays. In the case of the BMW design where the LPFP kicks first, I don't understand its function relative to the system it lives in.
Filippo
Because a checkless pump was not available at the time of design.
Its cheaper taking something of the shelf than making something from scratch.
Also another pro of a check valve is in very low fuel situations where the pump is starving as this will help when the pump is sucking air.
Walbro has realised the internal check valve is hurting the pump performance and its up to the fuel system builder to design and build their own
as most like myself do.
Lets be serious BMW will only build a system that needs to power the car to their specs, they will not spend extra money building a system to make 1000hp
when it only needs to make 500.
Its all about the bottom line and maximising profit.
Its cheaper taking something of the shelf than making something from scratch.
Also another pro of a check valve is in very low fuel situations where the pump is starving as this will help when the pump is sucking air.
Walbro has realised the internal check valve is hurting the pump performance and its up to the fuel system builder to design and build their own
as most like myself do.
Lets be serious BMW will only build a system that needs to power the car to their specs, they will not spend extra money building a system to make 1000hp
when it only needs to make 500.
Its all about the bottom line and maximising profit.
I've got the 535 pump installed and I went with full lines as well. It's not necessarily necessary but helps. I did it mainly because they will last longer while running full e85. They are higher flow though. If you need lines, reach out to Precision Raceworks. They can take care of you. Definitely go for the 535 pump though! I can run full e85 on the stock ekp no problem. I do recommend installing an inline check valve too as my car takes a few cranks and can be lazy on start ups without it.
^^^^ I also have the 535, without the check valve however. I've found that allowing the car to prime for a few seconds before cranking it over usually alleviates the lazy start up.
I didnt look into upgraded lines as yet, but its nice to know that there is an option. Thanks for sharing.
I didnt look into upgraded lines as yet, but its nice to know that there is an option. Thanks for sharing.
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