Mar 14, 2018
Hey guys, I’m installing a set of Pure stage 2 turbos in the near future along with my FBO. I will also be using 100% meth direct port (twisted kit) so I can up the boost. My goals are hitting 600whp. Question is will I be ok with the factory lp fuel pump or will I need to upgrade? I have read the Z4 pump puts out a lot more fuel vs the 335 setup. Has anyone found the limits?

I will also be testing the limits of my recently installed 335is clutch. Should have went with twin disc!


Oct 18, 2016
I wasn't aware of that being the case, but generally if you're using meth that will help your trims a little bit so if you're using gasoline+meth you should be able to hit 600. But if not, there are several fairly inexpensive LPFP solutions out there.You'd only need a stage 2 setup.

Twisted Tuning

Platinum Vendor
Oct 25, 2016
New York
First and foremost that 335is clutch will not handle 600tq for long. So if you are going for that, whoever you have tune it, make sure they keep the torque down to get some life out of the clutch. Im not sure how much flow the Z4 pump is, but you are correct, as i do believe it flows a bit more than the 335 but i would still invest in a Stage 2 at a minimum for the LPFP. Bbecause i don't think the pump itself is a higher flowing pump, but the stuff around it is less restrictive. Dont qoute me on that though. The direct port kit will help make up for some of the fuel, but better to have too much fuel capacity than too little.
  • Agree
Reactions: doublespaces


Mar 14, 2018
Thanks for the responses guys. I will order up a Walbro 450 just to be safe. I have not seen any diy vids for the Z4. I did see Fillippos write up though, sounds like it’s not a fun job.

Anyone know if the 450 is plug and play? I don’t think I will need the Hellcat pump for my power goals. I saw Fuel-it offers a kit but don’t see the point of purchasing a new bucket? Am I missing something?

Regarding the EPK, do these pop like a fuse when they see too much amperage? Will the 450 cause this? When they do pop do they disable the car? Should I carry a spare with me? Are they plug and play or do they require programming? Is there an upgraded unit available?


Aug 11, 2017
Ok ... look for advise from the tuners for the LPFP on the Z4. It's not like the E82/E90 LPFP. @BQTuning can provide first-hand experience as he's tuned many of the Z4's out there. I did the 450 as insurance for running E85. I would hardly call it necessary on the Z4. Unfortunately the Z4 lacks the LPFP pressure sensor so ... but guys tuning these cars can sort it out. My goal is circa 600whp with single barrel, E85 and 450 LPFP with all other stuff fresh (e.g. low miles hpfp, et al). I'm not there though, so my comments at that level mean nothing at this point.

It is a PITA to do on the Z4. Every other BMW owner on the planet has it elementary easy, in comparison. My advise would be do it when you need it. Making power is a staged development activity. If you have money to burn and time to burn, then just swap it. But ....

The 450 runs within amperage spec. I would not advise the 525. Fuel-It is selling it but to my knowledge, they actually have not done the homework to figure out how to actually run that pump in electronic components built for a 25A max, not 30A draw the 525 likes to hit. YMMV!

Good luck!


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