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Originally Posted by dzenno@ProTUNING Freaks

STAY AWAY from this pulley upgrade

B-A-D...OEM is not just a pulley, it is a harmonic balancer and I've heard of at least 2 people having bottom end issues after using it (no harmonic balancer material)..not worth the risk at all...NST was another company that offered it..

yeah i was thinking this, 'the oem one is weighted for harmonic balance isn't it??!?!'

i was wondering - when you go a single mass light flywheel... is the OEM dampener balanced to the OEM flywheel, does it cause balance/dampening issues of any sort when they weight on the other end is altered? "

Yesterday, 03:28 AM

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Originally Posted by Sticky

Well it seems all fuel issues aren't worked out yet as you referenced the lower rpm issues currently. And yes, no real need to rev it that high unless someone comes out with some crazy cams and heads.

we won't really know until someone gives it a go (well... until the ability to try is available)?

especially with the VTX kits, ASSUMING the injectors wouldn't fall over, and the valvetrain could handle it (and the bottom end too) if they can make 700whp at 7000rpm, they SHOULD be able to make 700whp at 8000rpm no? "

Yesterday, 03:24 AM

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Originally Posted by GeorgiaTech335Coupe

I think it's more because if you are opening up the engine anyway, might as well go stronger if available and stop a potential problem.

exactly my thoughts. just because it's not a problem yet doesn't mean it won't be "

Yesterday, 03:23 AM

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Originally Posted by JoshBoody

actually you were right. 3.75ms x 2 stroke/rev = 8000rpms

ahh my mistake, yeah 7.5ms per revolution @8K RPM , not per stroke, i got confused late at night haha - my bad @ajm8127 "

Yesterday, 03:21 AM

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Originally Posted by benzy89

I haven't scene anyone having head lifting problems, but has anyone really investigated whether or not it's an issue?? I feel like everyone is too busy focusing on that fact that stock N54s are hitting 700 WHP and having no issues, but we're strictly evaluating that from a tuning perspective (EGTs, Clean Data Logs, etc). It's not like the S65, where Gintani recognized the heads were lifting with high boost builds.

I imagine that if someone raised the N54 redline up to 8k RPMs and paired it with the Vargas Stage 3s/Single Turbo, lifting heads could become an issue. I agree that head studs won't "assist" in raising the redline, but the OEM headstuds will be beyond their capabilities at that point and it'll just be another necessary component when upgrading the motor to those levels.

it may turn out it's not an issue at all, but yeah, 30psi+ @ constant high revs, i wouldn't risk it..? "

Yesterday, 03:15 AM

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Originally Posted by BoostAddict

Are people having head lift issues, or do you guys just want upgraded head studs just because? They aren't gonna help with rev abilities. If anything rods bolts and a coated bearing since you're already doing the bolts, And of course valve springs as already mentioned.

i'm personally not aware of any lifted heads, though i do have a vague memory of one or two that have done some sort of damage to them?

for me? yeah pretty much just because, no one can guarantee it WONT long term, and once they're on the shelf, it's really a fairly inexpensive bit of insurance for high power builds.

i don't think anyone said it was to rev higher though? "

Yesterday, 03:14 AM

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Originally Posted by ajm8127

You are right. I was off by a factor of 2, possibly due to lack of coffee. It's annoying me that I can't replicate the error I made though.

I was also assuming it could not inject right at the start of the intake stroke due to lack of room in the cylinder, and I think the DI system can't inject during the entire compression stroke, only a portion, due to cylinder pressure. I was figuring a worst case of an injection event starting halfway through the intake stroke and ending halfway through the compression stroke.

i'll re-read the last discussion on it in the morning after i turn my brain off for the night - i remember this was answered correctly..

ED: a quick search says that homogeneous means it injects on the intake stroke, presumably intake stroke only? further googling later.

ED: "

05-17-2013, 10:12 AM

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Originally Posted by ajm8127

@V8Bait

Thanks, did not know this. I never made the connection between each 25% of injector duty cycle of a port injector = 1 stroke of a given piston.

FWIW, 8k rpm means each one of the four strokes will take 3.75 ms. I would love to see some data on pressure vs. flow rate for the DI injectors. So I would expect this to be about the time available for a DI engine to inject fuel at 8k rpm. At 80% DC a port injector would have 12 ms at the same rpm.

3.75ms? 3.75ms/stroke would be 16000 RPM (1000/3.75*60), it's 7.5ms/stroke... and .. is it the bottom of the compression stroke or start of the intake stroke - i presume it CAN start injecting at the start of the intake stroke, so 15ms to inject fuel - not 3.75

there's LOOSE data on the flow rates of the injectors at pressure given the manufacturer data - i know i managed to work out the best and worst possible case flow rates. it's... somewhere. "

05-17-2013, 09:28 AM

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Originally Posted by Mike@VAC

We can do cams if you wish. Early adopters pay a lot of $$$ of course. We have cams/springs/retainers/valves etc for just about every BMW engine already in stock.... N54 def is in motion. Demand is very low at this point but I'm sure that will change in a year or 2.

hehe, while i'd be entirely interested in some cams

i don't QUITE have that budget if we're talking about THOUSANDS of dollars hahaha

any idea on the time frame you're looking at for the valvetrain? aid year or two? or potential pricing?

unfortunately i'm looking at sooner rather than later "

05-17-2013, 12:13 AM

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Originally Posted by BavarianBullet

The DI doesnt work at high rpm arguement is false. GDI has been winning in serious racing for nearly 10yrs.

DI can inject a massive amount of fuel comared to a port injector. By design it is made to inject near TDC right before spark ignition and clearly does that just fine to a little over 7k right now in the n54 and over 8k in other production car engines.

All one has to do is start the injection sooner or add multiple injection events and you're fine, in theory. You just lose some of the cooling and other less important benefits but fueling is still there.

I think the block casting will have structural problems before we run out of injector.

N54 already operates in homogenous mode "

05-17-2013, 12:11 AM

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Originally Posted by Terry@BMS

We run an inline pump in our E92, and a single Walbro (normally) in our 135i. For this testing the 135i has the factory in tank pump. The inline is generally inferior for lower pressure targets but easier to install. Our inline DIY is ~$100 while the Vishnu inline option is $600+ and I have slammed their setup for the cost, dramatic marketing, and cheap pump used.

For very high pressure targets like we're going after with this testing an inline approach must be used despite the flow sacrifice.

If there was not sufficient flow on the low pressure side then low fuel pressure would drop rather than sticking at 100. As you'd be sucking the fuel from the pressure sensor in to the engine faster than the pumps can push it back to maintain pressure.

yep, fair enough

could you run a dual pump setup AND the inline, or would it be too much flow for it to handle and the inline pump itself becomes a restriction? or simply no point in it?

i mean... if you're trying to fix the midrange dip in high pressure by stepping up low pressure, but you can't flow enough fuel to support massive power in the upper RPM's...? one step at a time? haha "

05-16-2013, 11:11 PM

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Originally Posted by Terry@BMS

Sounds like you're confusing these tests results with the in tank pre regulator fuel pump tests we did. As a result of those tests I came to the conclusion that a single Walbro in tank or a single Walbro + the factory pump in parallel offered the best overall performance @ 70psi.

http://www.n54tech.com/forums/showpo...34&postcount=1

no i remember the original testing/upgrade where you put another pump in tank... but isn't the vishnu offering in in-line booster too?

i distinctly remember the inline pump being slammed in favour of parallel for various reasos

so now you've warmed up to the idea of having more pressure stepping up instead of flow on the low pressure side?

ED: never mind me, i never read that thread you linked, i had no idea you'd already tested an inline and showed positive results already. "

05-16-2013, 11:00 PM

05-16-2013, 10:09 PM

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Originally Posted by Terry@BMS

This is map 7 stock turbos so its around 480wtq. I have not tested this fuel pump setup on the dyno but during steady single gear pulls it seems OK. I'm starting to suspect something else is going on with the control valve during shifts but I won't be able to spend any more time with it until next week. Up next I'll need to do a more permanent mount of the line under the car, rig the JB4 up to control it, etc. At the very least it works just as well as the Walbro in tank thus far and I'm really in love with the concept of how this would work.

wait does this mean you're running inline instead of parallel?

weren't you putting down the idea of an inline pump in favour of a parallel pump not too long ago? "

05-16-2013, 10:06 PM

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Originally Posted by GeorgiaTech335Coupe

I talked to them before about it. It is supposed to come with upgraded valves, but they haven't got them from the manufacturer yet. No telling when they will come in. I've heard different things. Apparently, upgraded springs for the N54 are a big challenge.

hmmmm if it comes with more than they're stating... that may not be a bad price then...
unless they plan on upping the price

might sent them an email just in case

wonder what's so hard about the springs, there's countless designs in other motors, all of which have solutions "

05-16-2013, 09:05 PM

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Originally Posted by Terry@BMS

Fuel pressure drives everything. When it drops then trims and AFR go wacky as the DME struggles to sort it out.

The second run was just another run at 100psi where it happened to not nose dive until the 3->4. Maybe it's on the cusp of functioning properly. I guess what is missing from this log mix is a map on say map 1 where you'd see the actual fuel pressure target. The third log shows its working OK during steady state single gear pulls. At least, it was on that pull.

Since the pressure drop comes up at the shift most noticeably there may be an issue with the factory fuel mass control valve mapping. I connected a meter earlier today and noticed its giving a peak of 50% PWM. What I don't know is whether or not that is fully open so I'll need to bench test it.

mm fair enough

so the logs 2,3 are just managing to hold on (can see it dips a tiny bit), even though it's pretty much the same situation a log 1 - if you were to add a bit more boost/fuel demands, i assume the dip would be even greater? "

05-16-2013, 08:44 PM

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Originally Posted by VargasTurboTech

This is obviously not the case. I love how now that major power levels have been achieved everyone wants to talk about how crappy the head is and its limits. Reminds me of the stuff I read when I first joined these forums from a couple years back when the biggest players in the N54 game were saying the N54 couldn't make more then 500 in stock form without blowing up, then they raised it to 600 before it blows up. Now we are sitting at 725 with no engine work

go back a bit further, i can find some posts saying they expect the motor to give up around the 400-450mark lol

i do like that headwork is becoming a common thing now too "

05-16-2013, 08:38 PM

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Originally Posted by Terry@BMS

When it drops to around 6 in JB4 logs then you have serious problems. DME throws a fuel injection cutoff fault among other potential issues. In a perfect world it would hold close to its target with any boost / afr / fuel mix. Also keep in mind the high pressure pump has an easier time moving fuel at higher RPM than lower RPM.

so if i'm reading it right, around 5250rpm in graph 1, a bit after shifting everything takes a nosedive and it hits the bad 6... ?

how come graph 2 is a lot more stable looking? same with graph 3, not like 1 where trims drop out and takes fuel pressure with it? AFR's look a lot more stable too? "

05-16-2013, 08:30 PM

05-16-2013, 08:26 PM

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Originally Posted by GeorgiaTech335Coupe

Stage 3 does come with upgraded springs, I believe. But they haven't received any yet.

it doesn't list springs as an upgrade on the product page

it could be planned by them though? "

05-16-2013, 08:19 PM