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
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
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