N54 head work

[fmorelli]

I've got a few things cooking as we head toward disassembly of the Z4 for the next round of updates. We have the remaining pieces showing up to make the stainless steel outlets (thread here) for the Hydra Performance HP650's. I decided, in the name of asking for less PSI, to get the rather restrictive N54 head to breathe better. This thread is for the head work.

I purchased a long block to have a spare head to port. I spoke to a number of different folks about having the head ported, and landed with a friend in Wisconsin who will do the work. Ported N54 heads don't seem common, and few people have experience with them. VTT/Rebello have a very nice solution, undoubtedly top shelf. A special thanks to those guys for posting some comparison results from their work - this kind of information is fairly sparse. Conversations with other porting speciality shops yielded no experience with these heads.

So the plan is for the head to get ported and polished, and the valves tuliped. We intend to run stock valvetrain, with low-lift Schrick cams (courtesy of @Panzerfaust). As I understand it, these cams can be run with the stock springs, maintaining 7200rpm reline.

As somewhat of a contrast, Omar's 135i (@Hydra Performance) runs the bigger brother HP800's, bigger exhaust manifold, N53 head with valvetrain, high-lift Schrick cams, and 8,000rpm redline. His dyno pull on 93 octane fuel yielded 625whp at ~18psi ... that's DI only and pump gas. Impressive to say the least. We are running the junior version of all the pieces, if you will, but expect to be on E85, DI only as well, but with dual HPFP to manage the additional fuel volume and pressure needed with E85 at that our target power level. We'd like to see ~600whp and would be happy to see that under 20psi of boost.

Here's comparo on the cams:

We expect to have before and after flow bench numbers, which I'll post as information comes in, along with shots of the head work being performed.

Filippo

 

[fmorelli]

Here are some photos of the head which came out of a 535i ... this never knew what walnut blast meant ... this motor ate a drive belt through the front main seal. I bet the head thought it was going to lead a quite end-of-life in a junk yard. Not so!

Disassembly:



The ugly innards:



Off it goes to Wisconsin:



Filippo

 

[fmorelli]

Once in Wisconsin, the head went in to the dip tank for a few days. It's now awaiting flow bench before the port work begins.



Filippo

 

[GreyNBlueE92]

How many miles is the head? That's crazy

 

[fmorelli]

Good question. I don't know but that thing probably didn't run so well

Filippo

 

[ShocknAwe]

Will certainly be enjoying the ride reading your experiences with the N54 headwork journey! Going to be embarking myself although not as bespoke as yours.

 

[doublespaces]

Excellent project!

 

[Panzerfaust]

Excellent project!

Couldnt agree more! While it hurt a little bit to sell the cams, at least now I know they're going to one of the best causes possible lol. I know @fmorelli will provide some awesome data for the entire platform out of this, and I think itll put all the "cams arent good for anything but the highest tier builds" comments to rest since he isnt going for 900whp, just a badass streetcar that can hit the track whenever he wants.

 

[Rob09msport]

Womp womp guess I'll be the little bro that drank coffee from birth 650s on 93 no cams or porting dyno lmao
Seriously though what are thoughts on stock heads with low lift cams worth it ?

 

[gmagnus7]

Womp womp guess I'll be the little bro that drank coffee from birth 650s on 93 no cams or porting dyno lmao
Seriously though what are thoughts on stock heads with low lift cams worth it ?

I was wondering the same thing until I found that MMP head porting thread (although obviously biased considering he's selling the product). Regardless, judging from the stock flow numbers the difference in flow from 9.7mm to 11.5/10.5mm is literally almost nothing, like 5-10 cfm tops. So if anything the slight increase in duration might help make power. Interested to see if these results show the same or something different.

 

[Hydra Performance]

Keep in mind that even if flow plateaus at higher lifts, the added valve opening area still increases average discharge (flow) coefficient. And the stock N54 exhaust side certainly needs all the help it can get..

 

[gmagnus7]

Fair enough! I look forward to the results

 

[Rob09msport]

Keep in mind that even if flow plateaus at higher lifts, the added valve opening area still increases average discharge (flow) coefficient. And the stock N54 exhaust side certainly needs all the help it can get..

So bang for buck what's better head porting or cams?

 

[fmorelli]

So bang for buck what's better head porting or cams?

What, we're going to get all practical on this now, and put value on the dollar? Have you been talking to my wife?!

This question reminds me of a story: I took my oldest son to UVa for an admissions tour. The guide was a UVa employee and graduate. During the group tour, a girl asked, "If you could get an A in a regular Biology class, or a B in AP Biology, which is better for admissions?" The UVa employee replied, "An A in AP Bio would be."

Swapping the low-lift Schrick cam is certainly less expensive than porting. You don't have to pull the head (which then you've got gasket, bolt set, valve seals, intake manifold gaskets) and a bunch more work (assume DIY), and paying someone to clean the head and do the porting, and shipping both ways if not local. And you'd probably port a spare head for convenience of build so add that cost as well.

That being said, bang for the buck, I think you do both.

Filippo

 

[Panzerfaust]

So bang for buck what's better head porting or cams?

Largely I agree with Fillipo and the group who say porting + cams will give the best results, obviously.
Bang for buck though, the cams are a relatively easy job to do since the majority of the work is the same as changing your valve cover and as Omar said, our exhaust side can use all the help it gets.

My plan was to keep the head stock but upgrade the cams and rev further out with my 1Ks that can currently pull to redline, hoping the revs + increase in duration from the cams would allow me to get more power for each PSI and never need to run 30psi on a stock block to hit whatever, and I still may buy cams again in the future. Next time it might be with a ported head, but maybe not. I needed to get my high pressure fueling fixed (which it should be in a few days here now) and get a drag tire setup (which I still need to purchase) and I've had the cams sitting at the shop I use for like 6+ months before having them sit in my apartment for another 2-3 months, so I swapped them for getting my car track-ready first.

 

[Rob09msport]

I guess I should have worded that better. Basically which one is more beneficial I know obviously cam is cheaper but now comes the real conundrum. Which is better ported head low lift cam or high lift cam upgraded valve train. And panzer I'm hoping you get good results so we have a third party with no skin in game giving true feedback which I'm glad is you cause alot of people just praise what they have as best. That's how okada got away with their coils for so long lol

 

[Kommodore]

Is porting the N54 head more cost effective than getting an N53 head? Can you get the same valve sizes out of a ported N54 head?

 

[fmorelli]

The VTT link above, references a discussion with back-to-back measurements VTT/Rebello performed, providing some hard numbers (note the 2 page attachment embedded in Chris' first post):

https://bmw.spoolstreet.com/threads/vtt-tech-n54-head-flow.4748/

Cost effective - on the N53 if you are in the USA you have to source one from overseas. You'll need to run a modified exhaust manifold, and there are some modifications to the cooling passages, I believe, to do so. If N53 is what you desire, @Hydra Performance will sell you a head ready to bolt on to the N54 - and I'm sure you can get that from stock to built up with Schrick cams/valves/springs. You'll have to sort out your exhaust manifold connection, unless you order that head with Hydra's HP800's and their exhaust manifold modified already for the N53 head.

Hope this helps,

Filippo

 

[ShocknAwe]

I think the N53 kit Hydra sells is quite cost effective unless you are using N54 turbos with boysen turbofolds, see, 90% of turbos. The exhaust manifold is really the kicker and so unless buying Hydras custom N53 HP800s, stick with the ported N54 head.

For the N53, you can use stock N53 cams, or Hydra offers schricks in low or high lift configurations. I had to choose recently and while still torn I think the low lift schricks are best bang for the buck spent.

 

[fmorelli]

Here's a question. With a ported head running stock cams, why upgrade the valve springs? I've seen two references to doing this, but I've not been able to determine why.

Filippo