[thejeremyman9]

Originally Posted by gster335

thats interesting.. i wonder if anyone has personal experience with the hpd6 hpfp because MHD said it works without tuning or coding. Id like to know maybe where you got that info from.

It's in one of the aftermarket HPFP threads. Not sure which one, but you can find it if you dig through. Was it johnung who posted about it? AFAIK it was confirmed from a HPFP manufacturer and not just speculation. Yes, it is "plug and play" and works without tuning or coding but the issue was on the mechanical side.

[AmuroRay]

Originally Posted by thejeremyman9

It's in one of the aftermarket HPFP threads. Not sure which one, but you can find it if you dig through. Was it johnung who posted about it? AFAIK it was confirmed from a HPFP manufacturer and not just speculation. Yes, it is "plug and play" and works without tuning or coding but the issue was on the mechanical side.

I think the issue was actually not an issue, because the HPFP doesn't actually run off the camshaft, like it was claimed.

[thejeremyman9]

Originally Posted by AmuroRay

I think the issue was actually not an issue, because the HPFP doesn't actually run off the camshaft, like it was claimed.

I went back and found it. Read pages 28 and 29 here: https://f30.bimmerpost.com/forums/sh...589774&page=28

John first posted about it, then others followed up. For example:

Originally Posted by Bowenpuref3p

So I contacted dorch about the difference in designs between their b58 and n55 hpfp and retrofited b58 HDP5 hpfp. They said a n55 has the same plunger as the regular b58 HDP5 hpfp and you can run it without any risk of damage. But the b58tu HDP6 hpfp does have a few differences that could damage your cam lobes if used long term. Luckily I have the regular b58 hpfp retrofit and will be upgrading to a dorch pump as soon as I get my pure stg2 turbo installed. So it looks like your information agrees with what dorch told me today

[AmuroRay]

Originally Posted by thejeremyman9

I went back and found it. Read pages 28 and 29 here: https://f30.bimmerpost.com/forums/sh...589774&page=28

John first posted about it, then others followed up. For example:

https://f87.bimmerpost.com/forums/sh...&postcount=471

Originally Posted by F87source

Maybe but I think the answer is going to be no. Because spool talks about the pump cam lobe lift, are they talking about the lobe inside of the vacuum pump which is doing the lifting of the tapper at the bottom of the HPFP? Or are they referring to the B58 where the HPFP is actually driven off of the cam shaft - which is how everyone seems to be calculating these things because I think they developed these things for the b58 and then just ported it over to the n55 second and as a result calculations were done the same way. But if the are talking about the cam lobe in the vaccum pump: https://prussianmotors.com/2013-2017...e92-f10-28149/

Then spool is calculating it correctly.


Dorch is clear they are calculating on cam shaft so their data is wrong. "The table below serves as a reference for maximum fuel flow in cubic centimeters per camshaft revolution for various N55 fuel pump options. These calculations are based on the N55 cam lobe. Each engine will have varying fuel flow capacities depending on the lift and number of lobes on the camshaft."


Nostrum gives a LPH chart based on rpm but it is unclear how they calculated their numbers or if they give a measurement.


So in summary even comparing CC/rev is not accurate because the stroke distance changes if you use the wrong cam profile and thus less volume is pumped so you can't even compare it that way. So yeah now that I am looking into this area more cautiously I see the callous mistake I made before assuming the HPFP is also driven off of the cam shaft like the b58 when it does not, it is driven off of the vaccumn pump which is on the opposite side of the engine compared to the head so there is no way it can be cam driven (it is also driven by a chain so yeah dead give away if I had decided to look at the vaccum pump assembly earlier) - I am kind of beating myself over the fact that I didn't notice that before. Well that's what happens when you don't fully research a topic and just rely on manufacture data I suppose.

But what I said about the s55 is still true 2 hpfp's driven off the the chain which again is spun by the crank hub, and a mechanical water pump (I believe is belt driven or might be chain driven I actually never looked) also driven off of the crank hub provides alot more mass (and thus inertia it must overcome to do said speeding up and slowing down) that it has to spin up and slow down might be the reason why the S55 is much more proned to spinning the hub than an n54 and n55.

It's not Cam driven.

F87source - Can you confirm.

[bwillpom]

Thread bump but running e85 MHD stage 1 tune on a 15 x3 n55 with the pwg. Runs great and pulls about a 4.5 0-60.

Tbh car feels better than stock running Costco 92. Stock I had some minor start up shake and small idle variation.

That’s gone running e85.

Stock fuel system, stock everything.

Added the burbles on oem setting, very fun!

This tune is very attractive to me in MN with abundant e85 access at about $2.50 a gallon. Less boost on the turbo means I don’t really need to worry about the charge pipe too. I have an ARM Motorsport charge pipe on hand but I don’t see any reason to install it unless it breaks. Figure I can limp it home and install it if needed, any long trips I’ll just bring the pipe with and have a nearby shop install it.

Fairly minor mpg drop that is more than offset with premium costing north of $3.50.

[thejeremyman9]

Originally Posted by bwillpom

Thread bump but running e85 MHD stage 1 tune on a 15 x3 n55 with the pwg. Runs great and pulls about a 4.5 0-60.

Tbh car feels better than stock running Costco 92. Stock I had some minor start up shake and small idle variation.

That’s gone running e85.

Stock fuel system, stock everything.

Added the burbles on oem setting, very fun!

This tune is very attractive to me in MN with abundant e85 access at about $2.50 a gallon. Less boost on the turbo means I don’t really need to worry about the charge pipe too. I have an ARM Motorsport charge pipe on hand but I don’t see any reason to install it unless it breaks. Figure I can limp it home and install it if needed, any long trips I’ll just bring the pipe with and have a nearby shop install it.

Fairly minor mpg drop that is more than offset with premium costing north of $3.50.

Nice, very few people run the full E85 MHD maps, can you post a datalog? I wanna see what boost and timing looks like.

BTW i would consider replacing CP preventatively. If it blows you can damage the MAP sensor or something else, or suck pieces of plastic into the engine