Technical Hydra Performance 135 Leichtbau State of the Art Thread

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JBacon335

Specialist
Nov 7, 2016
79
Brick, NJ
Possible, but not worth the worry IMO. Sometimes if the vanos solenoids are going bad or need to be cleaned, actual setpoint can lag behind request a good bit, which could still cause an issue even if your tables were set correctly.
oh man, didn't think of that. Good call, that'll ruin a perfectly good set of valves lol
 

Hydra Performance

Corporal
Platinum Vendor
Jan 31, 2017
152
Forgive me for going all the going back and forth with this, but Tony Vargas brought to my attention that the valve reliefs on aftermarket pistons are no deeper than those on the stockers, which means that the information I received earlier was incorrect, and that the high-lifts can indeed be used with the stock pistons as per my original guess. Thanks T! In any case, I will be modelling the engine/valvetrain within Engine Analyzer Pro shortly, to figure out just how much (or how little) piston to valve clearance I will have @ max overlap
 
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Hydra Performance

Corporal
Platinum Vendor
Jan 31, 2017
152
Now back to our regularly scheduled programming, decided to take apart my shortblock as well to give everything a thorough inspection, in addition to pinning the crank and implementing my version of a crank hub fix. 2x tool steel pins locking the hub to the crankshaft, and 6x tool steel pins locking the timing chain sprocket to the hub, with a dab of a special high-temperature adhesive added between them for extra insurance. All the holes were EDM'd (not drilled) for an ultra precise fit. Pics below, oh and don't mind the trophies in the background :p
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Hydra Performance

Corporal
Platinum Vendor
Jan 31, 2017
152
More updates, managed to button up my superstock N54 motor just in time for the weekend, complete with crank hub fix, VAC Oil Pan baffle, fresh KolbenSchmidt bearings, N53 head, Supertech Ti retainers & Springs, and Schrick Hi-Lifts. Stock rotating assembly, and stock fasteners, all torqued to factory-spec. Here's hoping it can stay together @8k this time... Eye candy below:
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Jul 3, 2018
294
Saw this post on FB before here somehow, but I'll comment here instead.

Definitely interested in how the motor turns out as I'll have a similar setup shortly. Even after confirming that the high lifts dont require aftermarket pistons I stuck with the lower lift just to avoid any *potential* issues even though I'll be replacing both the VANOS gears and solenoids.

Out of curiosity, what made you go with the supertec springs instead of the dual springs VAC reccomends? And do you just expect to be able to rev to 8K because of the high lifts + springs? I was under the impression for a full usable 8K RPM you needed dual springs, lighter forged valves and lighter rods (but not pistons). Either way it's cool to see someone doing something very similar, my end setup will be the "low" lift Schrick cams + dual springs & retainers, VAC coated rod bearings, ARP hardware and SPLOCK hub fix, but I'm also maintaining the stock rotating assembly parts.
 

Hydra Performance

Corporal
Platinum Vendor
Jan 31, 2017
152
Dual springs are much too stiff for the task @ hand IMO. Ideally you want the lightest possible spring which gets the job done, and Supertech's beehive springs were, in my opinion, the best choice available. Beehive springs, by design, offer a higher resonant frequency than regular springs, allowing greater rpm before valve bounce for a given spring rate. Combine this with the fact that the Supertechs offer a >50% greater spring rate than stock + a significantly higher seat pressure (forgot the numbers, but I think it was close to double), and I have zero qualms about running these on my motor.

FYI, I would not run VAC coated bearings without checking clearances, and I would certainly not run ARP hardware on a stock cracked rod.
 
Apr 5, 2017
705
Jul 3, 2018
294
Dual springs are much too stiff for the task @ hand IMO. Ideally you want the lightest possible spring which gets the job done, and Supertech's beehive springs were, in my opinion, the best choice available. Beehive springs, by design, offer a higher resonant frequency than regular springs, allowing greater rpm before valve bounce for a given spring rate. Combine this with the fact that the Supertechs offer a >50% greater spring rate than stock + a significantly higher seat pressure (forgot the numbers, but I think it was close to double), and I have zero qualms about running these on my motor.

FYI, I would not run VAC coated bearings without checking clearances, and I would certainly not run ARP hardware on a stock cracked rod.
Interesting- I also looked at the Supertech before deciding on the Ferrea dual springs, so I was just curious, not questioning your building technique at all. I get wanting to use the lighter spring option, but personally after seeing Supertech only offers dual springs for every other BMW engine + the Ferrea dual springs still offer the rest of the benefits you mentioned in addition to prevention of valve drop and are designed with 12K RPM runs in mind I just ended up going that route for peace of mind. Either way I dont think you'll have issues related to Spring choice, just wanted to know your thought process since this is obviously one of the better thought out builds (understatement) this community has seen and I like the different perspectives from knowledgeable people - itd be boring if everyone ran the same exact build.

Regarding bearings, clearances will certainly be checked. The shop I'm using has installed them on numerous cars for over a decade from daily's to their own all out race builds and have a personal relationship with some people at VAC so I'm pretty confident in their capabilities. As for the ARP hardware I find that interesting, from my emails with VAC and ARP I was told they were specifically designed to be able to be used with the stock rods. I suppose we'll see there, worst case scenario is I'll have a good excuse to go with built internals and one of your N53 heads in the future.
 
Apr 4, 2018
71
Dual springs are much too stiff for the task @ hand IMO. Ideally you want the lightest possible spring which gets the job done, and Supertech's beehive springs were, in my opinion, the best choice available. Beehive springs, by design, offer a higher resonant frequency than regular springs, allowing greater rpm before valve bounce for a given spring rate. Combine this with the fact that the Supertechs offer a >50% greater spring rate than stock + a significantly higher seat pressure (forgot the numbers, but I think it was close to double), and I have zero qualms about running these on my motor.

FYI, I would not run VAC coated bearings without checking clearances, and I would certainly not run ARP hardware on a stock cracked rod.

Hey just curious what broke on the previous motor at 8K?
 
Nov 3, 2016
473
Colorado
As for the ARP hardware I find that interesting, from my emails with VAC and ARP I was told they were specifically designed to be able to be used with the stock rods. I suppose we'll see there, worst case scenario is I'll have a good excuse to go with built internals and one of your N53 heads in the future.
The ARP kit is specifically for other BMW applications, not the N54. ARP doesn't make an N54 spec kit. I'm not sure how much this matters though.

I am using ARP rod bolts on my stock-rod N54, so we'll see I guess.
 
Apr 4, 2018
71
Interesting- I also looked at the Supertech before deciding on the Ferrea dual springs, so I was just curious, not questioning your building technique at all. I get wanting to use the lighter spring option, but personally after seeing Supertech only offers dual springs for every other BMW engine + the Ferrea dual springs still offer the rest of the benefits you mentioned in addition to prevention of valve drop and are designed with 12K RPM runs in mind I just ended up going that route for peace of mind. Either way I dont think you'll have issues related to Spring choice, just wanted to know your thought process since this is obviously one of the better thought out builds (understatement) this community has seen and I like the different perspectives from knowledgeable people - itd be boring if everyone ran the same exact build.

Regarding bearings, clearances will certainly be checked. The shop I'm using has installed them on numerous cars for over a decade from daily's to their own all out race builds and have a personal relationship with some people at VAC so I'm pretty confident in their capabilities. As for the ARP hardware I find that interesting, from my emails with VAC and ARP I was told they were specifically designed to be able to be used with the stock rods. I suppose we'll see there, worst case scenario is I'll have a good excuse to go with built internals and one of your N53 heads in the future.

As long as you follow the stock rods torque spec, the arp hardware should be fine although it is overkill on a stock rod unless you plan on revving the stock rods past the stock rev limiter. The rod bolts, given everything else is done right , are stressed the most from high rpm where the tension load on the bolt is the highest at the top of exhaust stroke and beginning of the intake stroke. This tension on the bolt is not effected much by the torque output of the motor but has more to do with the rpm of the motor (reciprocating mass of the rod, pin and piston). Increasing RPM from stock puts way more load on the bolts then raising the torque output of the motor ( not considering the increased thermal load on the bearings) . I think alot of rod failures on the n54 are not related to the bolts but more to do with an oiling/ themal issue. This is more likely due to increased load on the bearing or an inadequate oiling system/ clearance for the power level intended.
 
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Jul 3, 2018
294
The ARP kit is specifically for other BMW applications, not the N54. ARP doesn't make an N54 spec kit. I'm not sure how much this matters though.

I am using ARP rod bolts on my stock-rod N54, so we'll see I guess.
I'll have to double-check my physical packaging before confirming I guess, but they definitely list an N54 ARP option. Maybe it's a newer offering compared to when you ordered depending on when that was, although maybe they're the same as an M54 kit and just been verified to work with the N54 - I dont know much at all about the M54's internals, but I'd at least expect if that engines stock rods could handle ARP hardware then surely the N54's could as they were designed for a boosted application? I suppose one of us will find out lol, like I said worst case scenario is I have an even stronger engine next go-round.
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Nov 3, 2016
473
Colorado
That is a kit specced for a different BMW engine, not an N54. VAC just did the research to find out the bolts dimensions would work on an N54, marked the price up, and sold them as N54.

When you use ARP rod bolts you are supposed to use ARP torque specs, not OEM. the ARP spec ended up being a lot higher than OEM on mine.
 
Apr 4, 2018
71
Oh nothing major, hub slipped the very first time I hit the hard rev limiter in 2nd, and all 12x exhaust valves got intimate with the pistons :)

LOL nothing major? love the optimisum . I had my hub slip as well , bent the crank killed the exhaust valves and ate the timing chain....nothing major though.
 

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