[HeavyMetalRocker]

Alright so running through the possibilities of my smoking cause I haven't ruled anything out as I have not yet disassembled anything. I will say that from a few opinions and the scenario in which the smoke is occurring is likely caused by leaking valve seals. Worst case scenario I'll need some head work done if things are pretty nasty in there. Does anyone have any experience with the VAC stage 1 or VAC in general for that matter?? Weighing out my options with how to approach this seemingly common issue of smoking and the possibility of the not so common exhaust valve leak. Is VAC the only N54 head available? I've searched plenty in the past 24 hours and there just isn't much covering this topic. Think this might be an issue as our engines are pushed with the higher mileage!!

[135Pats]

I would avoid doing any head polishing, porting, machining etc etc etc if you are going to retain stock frame turbos. TBH unless you are gunning for WR type numbers I don't see head work as useful on this platform. You loose low end spool and the very few results we've seen from worked heads shows gains at the VERY top of the curve. Hardly usable.

I would be more inclined to replace the head all together before doing any work to it. Used heads in good shape are not all that expensive.

[HeavyMetalRocker]

Originally Posted by 135Pats

I would avoid doing any head polishing, porting, machining etc etc etc if you are going to retain stock frame turbos. TBH unless you are gunning for WR type numbers I don't see head work as useful on this platform. You loose low end spool and the very few results we've seen from worked heads shows gains at the VERY top of the curve. Hardly usable.

I would be more inclined to replace the head all together before doing any work to it. Used heads in good shape are not all that expensive.

Well I'm not looking for record breaking numbers but I'm always open to having more power. More so gunning for something durable and strong that can handle tracking etc... I've got another couple of years of building the car and currently it's my dd until I decide what to get otherwise. Long term it's going to be my weekend track toy (because I'd rather build one than buy one). I'm also considering buying a used head and just working it and rebuilding it with better parts etc... Just trying to see where my money will be best spent to avoid any kind of bandaid job.

[OPe92]

I think there's someone on N 5 4 t e c h . c o m ruining a vac stage 3 head with RBs. Maybe he can chime in

[135Pats]

Originally Posted by HeavyMetalRocker

Well I'm not looking for record breaking numbers but I'm always open to having more power. More so gunning for something durable and strong that can handle tracking etc... I've got another couple of years of building the car and currently it's my dd until I decide what to get otherwise. Long term it's going to be my weekend track toy (because I'd rather build one than buy one). I'm also considering buying a used head and just working it and rebuilding it with better parts etc... Just trying to see where my money will be best spent to avoid any kind of bandaid job.

My concern is that you will lose power everywhere useful in the curve on stock frames.

It's not at all a bandaid to find a used but well kept head, then just slap that on. Imagine if you spend however many K on a worked head, end up losing power and spool, and it's not a valve stem/seal issue to begin with

[HeavyMetalRocker]

Originally Posted by 135Pats

My concern is that you will lose power everywhere useful in the curve on stock frames.

It's not at all a bandaid to find a used but well kept head, then just slap that on. Imagine if you spend however many K on a worked head, end up losing power and spool, and it's not a valve stem/seal issue to begin with

Yeah no kidding... a used rebuilt head may be the best costing route with the durability of being rebuilt

[Ingeniator]

Originally Posted by HeavyMetalRocker

Yeah no kidding... a used rebuilt head may be the best costing route with the durability of being rebuilt

As far as I was told but I haven't contacted them. Vac will sell just the valve train out of the upgraded head to customers. You would need to find a shop to check the head over and mag it. I wouldn't put a head back on a car without checking trueness and magnafluxing or die testing it.

You get your AFR figured out. I think high egt's may have been part of your smoking problem.

[jyeah]

Originally Posted by HeavyMetalRocker

Alright so running through the possibilities of my smoking cause I haven't ruled anything out as I have not yet disassembled anything. I will say that from a few opinions and the scenario in which the smoke is occurring is likely caused by leaking valve seals. Worst case scenario I'll need some head work done if things are pretty nasty in there. Does anyone have any experience with the VAC stage 1 or VAC in general for that matter?? Weighing out my options with how to approach this seemingly common issue of smoking and the possibility of the not so common exhaust valve leak. Is VAC the only N54 head available? I've searched plenty in the past 24 hours and there just isn't much covering this topic. Think this might be an issue as our engines are pushed with the higher mileage!!

To answer your question, VAC is not the only store with N54 head available. However, they are the only shop I know with people running N54 rebuilt/upgraded heads (including myself). The only other company I can think of that might offer a rebuilt head is ABR Houston, but I don't know anyone with their upgraded heads.

That said, I have RB's with VAC Stage 3 head. It does what it's advertised to do and my car has been running great with it. I posted a dyno not so long ago. In short, you'll likely be limited by either the fueling or your RB's.

I would definitely advise before you move forward with a rebuilt head, make sure that you really have leaking valve seals.

In addition to the rebuilt head, you will also be paying quite a lot for labor. If swapping turbos cost $1K, rebuilding your engine would only cost at least twice as much.

Feel free to PM if you have any questions.

[HeavyMetalRocker]

Originally Posted by Ingeniator

As far as I was told but I haven't contacted them. Vac will sell just the valve train out of the upgraded head to customers. You would need to find a shop to check the head over and mag it. I wouldn't put a head back on a car without checking trueness and magnafluxing or die testing it.

You get your AFR figured out. I think high egt's may have been part of your smoking problem.

Ahh cool, that may be a feasible option if they don't want my left testicle for the internals. As far as my afr I haven't had a chance to really dig any deeper. I'll reset all the adaptations tonight and see where that gets me. The JB4 supposedly has a run lean safety feature but who knows. I'll have to email Terry about that and wait the new typical week or so for a response. I am running the e85 backend and e65 in the tank so that may be some of the afr. It runs good otherwise but that's not to say something isn't going on.

[HeavyMetalRocker]

Originally Posted by jyeah

To answer your question, VAC is not the only store with N54 head available. However, they are the only shop I know with people running N54 rebuilt/upgraded heads (including myself). The only other company I can think of that might offer a rebuilt head is ABR Houston, but I don't know anyone with their upgraded heads.

That said, I have RB's with VAC Stage 3 head. It does what it's advertised to do and my car has been running great with it. I posted a dyno not so long ago. In short, you'll likely be limited by either the fueling or your RB's.

I would definitely advise before you move forward with a rebuilt head, make sure that you really have leaking valve seals.

In addition to the rebuilt head, you will also be paying quite a lot for labor. If swapping turbos cost $1K, rebuilding your engine would only cost at least twice as much.

Feel free to PM if you have any questions.

If I do go the VAC route I'm definitely sticking to stage 1. If I do in fact just rebuild the spare head I happened upon then it will be a full professional rebuild, honing, polishing, after market upgraded internals. Labor wise I'm fine because I'm pretty savvy with a wrench as are half of the actual mechanics in our car club.

Now, I'm definitely not diving straight into the head but I am mentally prepared to if need be. I'll definitely be checking the items on this list I stole from n54tech in no particular order.

1)Remove OCC and replace with new OEM vent hose (~$35)
2)Replace the valve cover gasket (~$35)
3)Replace RB Valve (~$50)
4)Replace valve cover (~$370, yes, extreme but has been known to crack and weep oil)
5)Check front turbo oil return line for kinks (common issue even on OEMs)

We'll probably check a few other things while were in there I'm sure aside from your basic items, turbo shaft play, any other possible oil leaks.

I foresee a painful road ahead of me...

[Allen@MOTIV]

We have a VAC stage 3 head on the track car. Lost a little spool down low but picked up about 50whp

[HeavyMetalRocker]

Originally Posted by Allen@PTF

We have a VAC stage 3 head on the track car. Lost a little spool down low but picked up about 50whp

I'm assuming that's on one of the single kits though?? I'm not to terribly concerned about losing a little low end as it's already an insane amount of torque twisting my tires around. It'd be nice if there was some flow bench data on all three head options.

[BigHoncho]

Originally Posted by Allen@PTF

We have a VAC stage 3 head on the track car. Lost a little spool down low but picked up about 50whp

Thats because of better flowing exhaust valves, which slow down the gas flow at lower rpms.
If you just optimize the intake side there won't be any downsides, but also not that much gain.

[Allen@MOTIV]

Originally Posted by HeavyMetalRocker

I'm assuming that's on one of the single kits though?? I'm not to terribly concerned about losing a little low end as it's already an insane amount of torque twisting my tires around. It'd be nice if there was some flow bench data on all three head options.

Yes, this a dyno from testing. On 93 octane(on a dyno that reads about 50whp lower than the average dynojet) we went from 550whp to 600whp but lost about 25ftlbs in the meat of the torque range. The increased flow does have it's trade offs in terms of port velocity at low to moderate engine speeds.

[HeavyMetalRocker]

Originally Posted by Allen@PTF

Yes, this a dyno from testing. On 93 octane(on a dyno that reads about 50whp lower than the average dynojet) we went from 550whp to 600whp but lost about 25ftlbs in the meat of the torque range. The increased flow does have it's trade offs in terms of port velocity at low to moderate engine speeds.

Those look like great gains and definitely look like they're worth the low end trade off. However, I'm not sure of what the gains and losses would be with my set up. Haven't found too many dynos of guys with RB's and the ones I have found are on pump only and mild tunes.

[CSL335i]

My n54 also has ported head (which was done by us). We did a tons of small modification related to the engine to have low end tourqe and high rpm power. Of course it is a balance between both of them.

Our custom made ball-bearing turbos have 30% larger wheels (inducer, excuder) and larger turbine houses than OEM turbos, and we can still maintane OEM boost curves with ported head as well. Our ceramic coating systems and the unique exhaust manifolds are also help to have great boost within no time.

Our turbos are pretty responsive with ported head as well even on low rpm.

As for stock turbos, i do not suggest to port the head.