ZPOST
BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read


Go Back   ZPOST > BMW Z4 Technical Talk > Engine, Exhaust, Drivetrain Modifications
  TireRack

SUPPORT ZPOST BY DOING YOUR TIRERACK SHOPPING FROM THIS BANNER, THANKS!
Post Reply
 
Thread Tools Search this Thread
      02-09-2016, 01:13 PM   #23
GuidoK
#buildnotbought
GuidoK's Avatar
10473
Rep
4,815
Posts

Drives: Z4 3.0i ESS TS2+
Join Date: Jul 2012
Location: Tinkering in the garage

iTrader: (0)

you can make calculations, but at least the graphs you posted dont add up, not by a long shot.
Or at least if its a compare between the same superchargers.

I mean at 6600rpm they make the same amount of boost.
At 6600rpm the adiabatic efficiency is 16% difference (a lot, but say its correct; it's in the graph), the overall efficiency (I calculate the twinscrew) is 60%, and the wheel hp difference is 50hp.
That means that at that point the twinscrew supercharger is consuming 125WHP/150crank (60/16*50) of power
You understand that there must be something wrong there dont you?
superchargers consume power, for sure, but not thàt much
__________________
Z4 3.0i | ESS TS2+ supercharger | Quaife ATB LSD | Brembo/BMW performance BBK front/rear | Schrick FI cams | Schmiedmann headers+cats | Powerflex/strongflex PU bushings | Vibra-technics engine mounts | H&R anti rollbars | KW V3 coilovers/KW camber plates | Sachs race engineering clutch | tons of custom sh#t

Last edited by GuidoK; 02-09-2016 at 01:20 PM..
Appreciate 0
      02-09-2016, 02:41 PM   #24
Westersund
Captain
Westersund's Avatar
Sweden
478
Rep
859
Posts

Drives: BMW
Join Date: Nov 2011
Location: Hallstahammar

iTrader: (1)

Quote:
Originally Posted by pokeybritches View Post
My point is that these are dated generalizations that are spread over forums with little factual basis. Fuel injection has become precise and dynamic, and a centrifugal supercharger produces lower discharge temperatures than a twin screw at the same boost levels (as I've shown with thermodynamics). No offense is intended of course, but I'm looking more to answer "why" I should go with a specific CR other than that's what others have done (which is not always the best way to do things).

"Why" could be answered with, "What's the maximum safe cylinder temperature in which to inject 93 octane fuel?" I can calculate supercharger discharge temps, make an estimate (with buffer) for aftercooler efficiency, and then estimate cylinder temps due to CR. Obviously there will need to be a margin of safety due to cylinder hot spots, extended use, and so on.
The only way to know for real is to try it out. It's cool that you wanna try something new, that however might proove not to be reliable and it will probably cost a lot of money. Trail and error.
Appreciate 0
      02-09-2016, 03:21 PM   #25
pokeybritches
Colonel
pokeybritches's Avatar
United_States
479
Rep
2,782
Posts

Drives: ESS/G-Power Z4M, VF Z4, 996tt
Join Date: Sep 2009
Location: Los Angeles

iTrader: (12)

Garage List
2006 BMW Z4M  [10.00]
2006 BMW Z4M  [8.50]
2003 BMW Z4 3.0i  [9.00]
Quote:
Originally Posted by GuidoK View Post
you can make calculations, but at least the graphs you posted dont add up, not by a long shot.
Or at least if its a compare between the same superchargers.
Which graphs are you looking at?

Quote:
Originally Posted by GuidoK View Post
I mean at 6600rpm they make the same amount of boost.
At 6600rpm the adiabatic efficiency is 16% difference (a lot, but say its correct; it's in the graph)
At 6600 rpm, the twin screw's adiabatic efficiency is 59.5% and the centrifugal is 70.5%

Quote:
Originally Posted by GuidoK View Post
...the overall efficiency (I calculate the twinscrew) is 60%, and the wheel hp difference is 50hp.
I used 9.0 CR for the twin screw. At 6600 rpm:

@11.5 CR for the centrifugal, there is a 10.3% difference in horsepower
@10.7 CR for the centrifugal, there is a 7.5% difference in horsepower

You're missing the effect of the change in CR. I multiplied the base power by the change in CR using the rule of thumb of 4% per point in CR. The 2.5 point difference equates to 10% more power at 11.5 CR. This was part of the exercise... to see whether low compression / high boost twin screw trumped high compression / high boost centrifugal... and the differences in power consumed, discharge temp, etc.

One thing to note is that the numbers are only accurate at wide open throttle. At part throttle, efficiency is difficult to estimate and would probably require modeling software.

Quote:
Originally Posted by GuidoK View Post
That means that at that point the twinscrew supercharger is consuming 125WHP/150crank (60/16*50) of power
No. I have a separate graph of horsepower consumed. At 6600 rpm, the twin screw is consuming 17.6 hp, while the centrifugal is consuming 16.2 hp.

Quote:
Originally Posted by GuidoK View Post
You understand that there must be something wrong there dont you?
superchargers consume power, for sure, but not thàt much
There were generalizations made for the behavior of the different types of superchargers. However, most of the rest of it... other than using the rule of thumb for CR; and (wheel horsepower) = (stock NA wheel power)(CR change)(PR) - (horsepower consumed by the supercharger)... is pretty accurate. I am more than happy to share the formulas I used so you can draw your own conclusions.
__________________


VF Engineering Z4 3.0i, ESS Z4M, G-Power Z4M, 996 Turbo
Appreciate 0
      02-09-2016, 03:46 PM   #26
pokeybritches
Colonel
pokeybritches's Avatar
United_States
479
Rep
2,782
Posts

Drives: ESS/G-Power Z4M, VF Z4, 996tt
Join Date: Sep 2009
Location: Los Angeles

iTrader: (12)

Garage List
2006 BMW Z4M  [10.00]
2006 BMW Z4M  [8.50]
2003 BMW Z4 3.0i  [9.00]
For anyone that wants to calculate efficiencies on their own, here are the compressor maps:

http://www.lysholm.us/pdf/diagram_lys1600ax.pdf

http://www.vortechsuperchargers.com/...i-trim_map.pdf

To calculate CFM, you can use this link:

http://www.mk5cortinaestate.co.uk/calculator3.php

Pressure ratio (the vertical axis) = [(ambient air pressure + boost pressure) / (ambient air pressure)]... or (1 + ambient air pressure / boost pressure). I used 14.7 psi for the ambient air pressure.

To help out, here are a few data points:

Lysholm
(rpm): PR / CFM / m^3/min
3k rpm: 1.81 / 287 / 8.2
4k rpm: 1.91 / 404 / 11.5
5k rpm: 1.95 / 516 / 14.6
6k rpm: 1.97 / 624 / 17.7
6.8k rpm: 1.99 / 714 / 20.2

Vortech
(rpm): PR / CFM
3k rpm: 1.15 / 182
4k rpm: 1.30 / 275
5k rpm: 1.53 / 390
6k rpm: 1.79 / 568
6.8k rpm: 2.05 / 739
__________________


VF Engineering Z4 3.0i, ESS Z4M, G-Power Z4M, 996 Turbo
Appreciate 0
      02-09-2016, 04:59 PM   #27
GuidoK
#buildnotbought
GuidoK's Avatar
10473
Rep
4,815
Posts

Drives: Z4 3.0i ESS TS2+
Join Date: Jul 2012
Location: Tinkering in the garage

iTrader: (0)

CR is? compression ratio?
That is a fixed value right? we're using the same engine or not?

anyway consuming 17hp or so is a realistic value.

I calculated the consumed power by output power difference at the same boost. I mean I assume we use a cooler inbetween.
Then that difference can only be attributed to the difference in adiabatic efficiency. (where the centrifugal one is 16% or so more efficient. Not on a scale of 0-100, but when one of them is set at 100%. so it's 10% higher, and 16% more efficient.
For instance if you have one supercharger that has a 25% adiabatic efficiency, and another one has 50% efficiency, it is twice as efficient, or 100% more efficient.)
If you attribute that 50hp difference at same boost, that must come from that 16% difference. If you dont cool your air its a different story, but I dont think you're gonna make 400whp without an intercooler
__________________
Z4 3.0i | ESS TS2+ supercharger | Quaife ATB LSD | Brembo/BMW performance BBK front/rear | Schrick FI cams | Schmiedmann headers+cats | Powerflex/strongflex PU bushings | Vibra-technics engine mounts | H&R anti rollbars | KW V3 coilovers/KW camber plates | Sachs race engineering clutch | tons of custom sh#t
Appreciate 0
      02-09-2016, 05:21 PM   #28
pokeybritches
Colonel
pokeybritches's Avatar
United_States
479
Rep
2,782
Posts

Drives: ESS/G-Power Z4M, VF Z4, 996tt
Join Date: Sep 2009
Location: Los Angeles

iTrader: (12)

Garage List
2006 BMW Z4M  [10.00]
2006 BMW Z4M  [8.50]
2003 BMW Z4 3.0i  [9.00]
I plan to build the engine, as in aftermarket pistons/rods/head studs/etc.

By CR I mean compression ratio. Since I am building the engine, I can spec the compression ratio I want. The TS3 uses a 9:1 CR as far as I know. With the Vortech, I wanted to take advantage of a higher CR, if I could, and see what that CR would provide me. It seems that even with a higher CR and more boost, it won't be much faster (if at all) than a TS3-like setup (14-15 psi, 9:1 CR). I knew a high compression Vortech would make less power down low, but I was surprised how much, and how it would likely not be faster even with extra top end.

FWIW, the new S55 in the M3/M4 has a 10.2 CR and runs over 18 psi stock. Aftermarket tunes take it higher. There are supercharger kits out for the S54 (11.5 CR) that run 12 psi of boost at a much greater flow (so aftercooling is less effective).
__________________


VF Engineering Z4 3.0i, ESS Z4M, G-Power Z4M, 996 Turbo
Appreciate 0
      02-09-2016, 05:30 PM   #29
GuidoK
#buildnotbought
GuidoK's Avatar
10473
Rep
4,815
Posts

Drives: Z4 3.0i ESS TS2+
Join Date: Jul 2012
Location: Tinkering in the garage

iTrader: (0)

I think 18psi stock is pretty high. I think n54 'only' runs 9psi stock. That's a pretty average value I think (not for supercars of course)
Obviously there is a 150hp or so difference.... (i dont know exactly how much power that engine makes...)
__________________
Z4 3.0i | ESS TS2+ supercharger | Quaife ATB LSD | Brembo/BMW performance BBK front/rear | Schrick FI cams | Schmiedmann headers+cats | Powerflex/strongflex PU bushings | Vibra-technics engine mounts | H&R anti rollbars | KW V3 coilovers/KW camber plates | Sachs race engineering clutch | tons of custom sh#t
Appreciate 0
      02-13-2016, 09:29 AM   #30
pokeybritches
Colonel
pokeybritches's Avatar
United_States
479
Rep
2,782
Posts

Drives: ESS/G-Power Z4M, VF Z4, 996tt
Join Date: Sep 2009
Location: Los Angeles

iTrader: (12)

Garage List
2006 BMW Z4M  [10.00]
2006 BMW Z4M  [8.50]
2003 BMW Z4 3.0i  [9.00]
Before I start swapping pistons and rods, I wanted to see if there would be any benefit to using a smaller pulley on a centrifugal setup, and adding a wastegate between the supercharger discharge and throttle body to control boost levels. The engineer in me doesn’t like the idea of it because it’s an inefficient way of doing things. Regardless, I considered doing it to get max boost from ~6k rpm to redline, with the tradeoff of higher discharge temperatures and more power consumed by the supercharger.

In other words, I’d get more low end and midrange, at the expense of peak power and efficiency.

My tuner says he can tune around it. I think part throttle would be hard to tune around, because you have two competing discharges. The intake wastegate and bypass valve are both dumping boost (unless the bypass opening dropped boost pressure enough that the wastegate closed). The ECU is using the info given to it by the MAF sensor for fuel calculations, so the car would need to be tuned to estimate how much air is being dumped through the wastegate, and how much is being dumped through the bypass. At full throttle or off throttle, things are better defined.

For the estimations, I used the same boost curve that I used previously for the 14.5 psig twin screw and 15.5 psig centrifugal (henceforth, I’ll drop the “g” from psig). I multiplied each 100 rpm increment by a fraction related to the new peak boost (so in this case, I multiplied each data point by 8.5/14.5 for the twin screw and [8.5, 12, 15, 18]/15.5 for the centrifugal). I did not go back and recalculate the compressor efficiency at every single data point. I did glance at the compressor maps, and the twin screw operates just above the “sweet spot” at 14.5 psi, and just below it at 8.5 psi; the centrifugal starts out in an area not covered on the compressor map (so data would need to be extrapolated), then moves towards the “sweet spot” of 73% efficiency. For the purposes of what I’m showing, a 5% change in compressor efficiency is irrelevant, since it only equates to a few degrees of discharge temperature and tenths of a horsepower.

The 15 psi and 18 psi pulleys would probably require a whole new pulley set to avoid belt slip, since the supercharger pulley would be too small with the standard crankshaft pulley, and the power required to turn it is higher. A Vortech SCi trim compressor would need to be spun to about 53k rpm (2.36” pulley using the stock 5.11” crank pulley… and that won’t happen without serious belt slip :lol).



First is boost pressure. Peak boost is reach at:

6800 rpm, 8.5 psi pulley
5900 rpm, 12 psi pulley
5300 rpm, 15 psi pulley
4900 rpm, 18 psi pulley

Even with maxing out the centrifugal supercharger, the twin screw has a huge advantage at low rpm.





Next we have the volume flow rate (cfm) of air dumped by the wastegate, and air passing through the throttle body. Ideally, only the air that is passing through the throttle body would have passed through the intercooler. The air that is not going to be used by the engine would be dumped before it passed through an intercooler. All things being equal, a lower volumetric flow rate means cooler air will exit the intercooler and into the engine, because there is less hot air to cool.



If the boost pressure graph shows the advantages of smaller pulleys, the discharge temperature graph is one of the areas where the downsides appear. I used an ambient temperature of 70 deg F, like with my previous high boost analysis (by the way, “standard day” is actually 59 deg F).

Obviously, some sort of aftercooling is necessary. Max discharge temps for each setup:

174 deg F, 8.5 psi
209 deg F, 12 psi
236 deg F, 15 psi
261 deg F, 18 psi
196 deg F, twin screw

When I lived in the California desert, ambient temperatures regularly got up to 110 deg F.



222 deg F, 8.5 psi
259 deg F, 12 psi
289 deg F, 15 psi
316 deg F, 18 psi
246 deg F, twin screw

I think we can agree that a well-developed means of cooling is necessary.

A smaller pulley is a compromise. It provides the midrange benefits of a high boost setup without the stress of high boost pressures, which is great for a stock engine. Because the volumetric flow rate of air entering the intercooler is lower, less cooling capacity is required, even if discharge temperatures are the same.

Then again, you deal with many of the downsides of a high boost setup, without enjoying the significant power advantages that high boost provides. The power required to spin the supercharger is the same whether you use the boost or dump it, so there’s a lot of waste:



Using the formulas I used previously, we can estimate wheel horsepower. Again, this doesn’t take into account power adders such as headers, FI-spec camshafts, or head work. It also doesn’t include losses due to intercoolers, heat of the intake air, or conservative tuning.



IMHO, a 12 psi pulley, with an 8.5 psi wastegate dump, appears to be the best compromise for a centrifugal setup. Max boost comes in before 6k rpm. Discharge temperature and horsepower consumed by the supercharger are mildly greater than a twin screw at high rpm, and it will run cooler and be more economical everywhere else. However, for maximum average horsepower at identical peak boost levels, you can’t beat a twin screw.

Overall average horsepower, 3k-6.8k rpm:
226 whp, 8.5 psi pulley
240 whp, 12 psi pulley
247 whp, 15 psi pulley
250 whp, 18 psi pulley
264 whp, 8.5 psi twin screw

Average horsepower, 4k-5.5k rpm:
216 whp, 8.5 psi pulley
233 whp, 12 psi pulley
247 whp, 15 psi pulley
255 whp, 18 psi pulley
263 whp, 8.5 psi twin screw

Average horsepower, >5.5k rpm:
281 whp, 8.5 psi pulley
297 whp, 12 psi pulley
295 whp, 15 psi pulley
291 whp, 18 psi pulley
298 whp, 8.5 psi twin screw

If you’ve got a centrifugal supercharger, it may be worth pursuing this mod, along with aggressive gearing to minimize your time spent outside of boost.
__________________


VF Engineering Z4 3.0i, ESS Z4M, G-Power Z4M, 996 Turbo
Appreciate 0
      02-13-2016, 10:10 AM   #31
pokeybritches
Colonel
pokeybritches's Avatar
United_States
479
Rep
2,782
Posts

Drives: ESS/G-Power Z4M, VF Z4, 996tt
Join Date: Sep 2009
Location: Los Angeles

iTrader: (12)

Garage List
2006 BMW Z4M  [10.00]
2006 BMW Z4M  [8.50]
2003 BMW Z4 3.0i  [9.00]
Here are more details of the setup I was looking at:

- High boost pulley (12/15/18 psi at redline)
- Wastegate on intake tract set to 8.5 psi. This could be controlled with an electronic boost controller.

Supercharger discharge --> Piping --> Wastegate --> Piping --> Intercooler --> Throttle Body
__________________


VF Engineering Z4 3.0i, ESS Z4M, G-Power Z4M, 996 Turbo
Appreciate 0
      02-13-2016, 10:59 AM   #32
Steeler
Colonel
Steeler's Avatar
2422
Rep
2,697
Posts

Drives: Built not Bought 04 Z4 VF
Join Date: Feb 2013
Location: Kitchener Ontario Canada

iTrader: (2)

Josh as you and I have discussed and as I have posted on other forums, I am moving forward with this idea as a recirculating BPV in the charge pipe. I will be experimenting with different springs until I get the psi I desire. It will not be as high as you are contemplating but I also would like the higher boost in low to mid range rpm and limit the boost at the top end. I will likely "leak off" at 10-12 psi. We have the same tuner and he confirms he can tune for this as long as it is recirculated.
It will take some experimentation but the idea is fundamentally sound.
I will be reporting my progress
__________________
W2A Intercooled Vortech V3Si, custom ducting, Alpha N, 60# Bosch,2.62 pulley, multi port WMI, Severn Tuning(pokeybritches), Tial, magnaflow,SS race muffler, 42 design,3.91LSD, H&R, Hotchkis,ST coils,Konis, Megan camber arms, AKG SS, Nylon mounts, Poly bushings, Carbon interior, CF Aero.APEX
Appreciate 0
      02-13-2016, 12:21 PM   #33
pokeybritches
Colonel
pokeybritches's Avatar
United_States
479
Rep
2,782
Posts

Drives: ESS/G-Power Z4M, VF Z4, 996tt
Join Date: Sep 2009
Location: Los Angeles

iTrader: (12)

Garage List
2006 BMW Z4M  [10.00]
2006 BMW Z4M  [8.50]
2003 BMW Z4 3.0i  [9.00]
Dave, your idea with a recirculating bypass should work. The only thing that would be different is the hot boosted air is being dumped back into the intake pre-supercharger, so inlet temperatures will rise (and therefore so will discharge temperatures). I'm not sure if water/meth alone would be enough for cooling... I'm not saying it won't be, but I would need to do some thinking on psychrometrics.

I built a calculator that's pretty handy. I can shoot it your way if you're interested... or, if you give me some specifics of a few different setups, I can graph them out.
__________________


VF Engineering Z4 3.0i, ESS Z4M, G-Power Z4M, 996 Turbo
Appreciate 0
      02-13-2016, 12:31 PM   #34
Steeler
Colonel
Steeler's Avatar
2422
Rep
2,697
Posts

Drives: Built not Bought 04 Z4 VF
Join Date: Feb 2013
Location: Kitchener Ontario Canada

iTrader: (2)

Thanks Josh,
I have been contemplating adding a third WMI nozzle in my system.
I have one pre blower at the bend behind the blower, a second in the nose of the blower post compression and will likely add another just ahead of the TB.
I might take you up on the graphing offer once I get deeper into it
__________________
W2A Intercooled Vortech V3Si, custom ducting, Alpha N, 60# Bosch,2.62 pulley, multi port WMI, Severn Tuning(pokeybritches), Tial, magnaflow,SS race muffler, 42 design,3.91LSD, H&R, Hotchkis,ST coils,Konis, Megan camber arms, AKG SS, Nylon mounts, Poly bushings, Carbon interior, CF Aero.APEX
Appreciate 0
      02-15-2016, 06:24 AM   #35
spunnn
New Member
3
Rep
12
Posts

Drives: z4
Join Date: Apr 2015
Location: spain

iTrader: (0)

I have to read this with time, but if i undertand you have to put smaller pulleys to gain a lot of midrange until 6k rpm but limit psi in the high revs with a wastegate system? Regards

Anton
Appreciate 0
      02-15-2016, 07:27 AM   #36
GuidoK
#buildnotbought
GuidoK's Avatar
10473
Rep
4,815
Posts

Drives: Z4 3.0i ESS TS2+
Join Date: Jul 2012
Location: Tinkering in the garage

iTrader: (0)

I think he means blowoff valve (or better: compressor bypass valve).
A wastegate technically limits the propulsion (turbo engines terminology)

I wonder if this idea is also used commercially (I mean in mass produced engines). There are not that many engines fitted stock with centrifugal superchargers I think.
But I like the idea to better use the centrifugal compressors' bandwith.
__________________
Z4 3.0i | ESS TS2+ supercharger | Quaife ATB LSD | Brembo/BMW performance BBK front/rear | Schrick FI cams | Schmiedmann headers+cats | Powerflex/strongflex PU bushings | Vibra-technics engine mounts | H&R anti rollbars | KW V3 coilovers/KW camber plates | Sachs race engineering clutch | tons of custom sh#t
Appreciate 0
      02-15-2016, 10:57 AM   #37
pokeybritches
Colonel
pokeybritches's Avatar
United_States
479
Rep
2,782
Posts

Drives: ESS/G-Power Z4M, VF Z4, 996tt
Join Date: Sep 2009
Location: Los Angeles

iTrader: (12)

Garage List
2006 BMW Z4M  [10.00]
2006 BMW Z4M  [8.50]
2003 BMW Z4 3.0i  [9.00]
Yeah, I used "wastegate" generically (and probably incorrectly). Really it would be a bypass or blow off valve that is boost pressure actuated, not vacuum actuated. However, depending on whether it is a bypass or blow off valve would affect placement.

A blow off would be best, but may have tuning and drivability problems. It should be placed before an intercooler.

A bypass is what the non-M would need to use, since the supercharger tunes still utilize the MAF sensor. The bypass would be best placed post-intercooler. The air compressed by the supercharger is heated by both the natural heat of compression, and the inefficiency of the supercharger. You want to limit the hot air being recirculated back into the intake, and cool it first if you can. Basically if you convert the temperature from deg F to deg R (or from deg C to deg K), you can figure out how hot the discharge air would be under an ideal, "adiabatic" compression (where the supercharger is 100% efficient and adds no heat of its own, only the natural heat of compression). Then plug in the supercharger's efficiency (pulled from the compressor map) at a particular pressure ratio (y-axis) and volumetric flow (x-axis), and you can find the actual discharge temperature. The actual discharge temperature will be higher than the ideal temperature.

What this means is when the air is recirculated back into the intake and allowed to expand, it will be hotter than ambient. Every time it passes through the compressor and back through the bypass, it gets hotter. After a few cycles it can get very hot. So, this is one reason why there is a point of diminishing returns with this setup. If you use say the 18 psi pulley with a bypass because it initially appears to offer better performance, you will be heating up the air and dumping more than half of it back into the intake to be reheated again. It will add even more heat to the system than I have shown on the graphs. Plus there is more power required to spin the supercharger, and running it at a higher speed will shorten its life.

One last thing to note - too much air flowing back into the intake can affect MAF sensor readings, and it may start "counting the same air twice".
__________________


VF Engineering Z4 3.0i, ESS Z4M, G-Power Z4M, 996 Turbo
Appreciate 0
      03-31-2016, 07:06 PM   #38
Steeler
Colonel
Steeler's Avatar
2422
Rep
2,697
Posts

Drives: Built not Bought 04 Z4 VF
Join Date: Feb 2013
Location: Kitchener Ontario Canada

iTrader: (2)

Quote:
Originally Posted by pokeybritches View Post
Dave, your idea with a recirculating bypass should work. The only thing that would be different is the hot boosted air is being dumped back into the intake pre-supercharger, so inlet temperatures will rise (and therefore so will discharge temperatures). I'm not sure if water/meth alone would be enough for cooling... I'm not saying it won't be, but I would need to do some thinking on psychrometrics.

I built a calculator that's pretty handy. I can shoot it your way if you're interested... or, if you give me some specifics of a few different setups, I can graph them out.
Not to to hijack your thread Josh.
Here is what I came up with for a "relief valve" to bleed off excess boost resulting from the smaller pulley. Down in the depths behind all the hoses is another WMI nozzle to assist with the increased boost.
The strut bar has been removed for access but goes back in.
The plumb back valve in the intake tract is by Turbosmart and is plumbed into the existing BPV line recirculating between the MAF and the blower.
The valve comes with 3 different pressure springs that I will need to experiment with to achieve to the relief pressure I am looking for. It may come to having to shim one of the springs to achieve that.
I have yet to start the car this spring but that should happen this weekend.
I will report back with findings.
Attached Images
 
__________________
W2A Intercooled Vortech V3Si, custom ducting, Alpha N, 60# Bosch,2.62 pulley, multi port WMI, Severn Tuning(pokeybritches), Tial, magnaflow,SS race muffler, 42 design,3.91LSD, H&R, Hotchkis,ST coils,Konis, Megan camber arms, AKG SS, Nylon mounts, Poly bushings, Carbon interior, CF Aero.APEX
Appreciate 0
      02-07-2017, 12:33 PM   #39
avalaugh
Registered
0
Rep
4
Posts

Drives: 330ci Clubsport
Join Date: Feb 2017
Location: United Kingdom

iTrader: (0)

So how's this all developing ?

I've signed up to this forum purely because I stumbled across this thread on a google search.

I've got an E46 330ci running most items you've discussed in this thread. I'm looking to up the boost too but want to know which thickness MLS headgasket to go with, engine has never been opened.

I'll post some pictures once I've worked out how.
Appreciate 0
      02-07-2017, 12:38 PM   #40
avalaugh
Registered
0
Rep
4
Posts

Drives: 330ci Clubsport
Join Date: Feb 2017
Location: United Kingdom

iTrader: (0)

So how's this all developing ?

I've signed up to this forum purely because I stumbled across this thread on a google search.

I've got an E46 330ci running most items you've discussed in this thread. I'm looking to up the boost too but want to know which thickness MLS headgasket to go with, engine has never been opened.

I'll post some pictures once I've worked out how.
Attached Images
    
Appreciate 0
      02-07-2017, 01:59 PM   #41
avalaugh
Registered
0
Rep
4
Posts

Drives: 330ci Clubsport
Join Date: Feb 2017
Location: United Kingdom

iTrader: (0)



Appreciate 0
      02-07-2017, 04:57 PM   #42
Steeler
Colonel
Steeler's Avatar
2422
Rep
2,697
Posts

Drives: Built not Bought 04 Z4 VF
Join Date: Feb 2013
Location: Kitchener Ontario Canada

iTrader: (2)

Quote:
Originally Posted by avalaugh View Post
So how's this all developing ?

I've signed up to this forum purely because I stumbled across this thread on a google search.

I've got an E46 330ci running most items you've discussed in this thread. I'm looking to up the boost too but want to know which thickness MLS headgasket to go with, engine has never been opened.

I'll post some pictures once I've worked out how.
What pressure you at now?
With the IC you should be good for at least 12psi.
I have not touched my head yet. Only time will tell if I get head lift at 12psi.

Guys on this forum are incredibly knowledgeable, but you may want to try a couple of the other forums for experienced input on FI

I have PM'd you.
__________________
W2A Intercooled Vortech V3Si, custom ducting, Alpha N, 60# Bosch,2.62 pulley, multi port WMI, Severn Tuning(pokeybritches), Tial, magnaflow,SS race muffler, 42 design,3.91LSD, H&R, Hotchkis,ST coils,Konis, Megan camber arms, AKG SS, Nylon mounts, Poly bushings, Carbon interior, CF Aero.APEX
Appreciate 0
      02-09-2017, 04:09 AM   #43
avalaugh
Registered
0
Rep
4
Posts

Drives: 330ci Clubsport
Join Date: Feb 2017
Location: United Kingdom

iTrader: (0)

Only running 5.8psi, currently on a 4" pulley, wanting to up boost to around 15-16psi, so will be fitting a MLS headgasket and some ARP HEAD STUDS before I do. Would love some advice on what thickness head gasket to install.

I have a host of other mods but won't bore this forum with them as it's vehicle specific not engine.
Appreciate 0
      02-12-2017, 02:51 AM   #44
pokeybritches
Colonel
pokeybritches's Avatar
United_States
479
Rep
2,782
Posts

Drives: ESS/G-Power Z4M, VF Z4, 996tt
Join Date: Sep 2009
Location: Los Angeles

iTrader: (12)

Garage List
2006 BMW Z4M  [10.00]
2006 BMW Z4M  [8.50]
2003 BMW Z4 3.0i  [9.00]
Quote:
Originally Posted by avalaugh View Post
Only running 5.8psi, currently on a 4" pulley, wanting to up boost to around 15-16psi, so will be fitting a MLS headgasket and some ARP HEAD STUDS before I do. Would love some advice on what thickness head gasket to install.

I have a host of other mods but won't bore this forum with them as it's vehicle specific not engine.
Nice setup!

With an MLS head gasket you will lower CR and lose bottom end power. The only reason to lower CR is to prevent detonation because the intake charge is too hot. With water/meth only, S54's are able to run double digit boost numbers, so I don't think there's any reason why our 10.2 CR motors can't run more boost with proper tuning.

The first design limit you will encounter (assuming proper tuning) is the head lifting, and then possibly the intake manifold (though I haven't found a definite answer here). ARP head studs will prevent the head from lifting. Fortunately - or unfortunately, depending on your goals - centrifugal superchargers increase torque where it normally falls off at the top of the rpm band. Head lift is related to torque more than horsepower.

I'm still planning to proceed with this build, but it's #3 on the list. First I'm looking to buy a house; next I have a car I'm looking to purchase. Then I will pull the motor myself once I'm settled this summer/fall. Because of the car's high miles and age, I'll be doing a full rebuild. So, plans have been delayed a bit, but I'm still going forward with the build.
__________________


VF Engineering Z4 3.0i, ESS Z4M, G-Power Z4M, 996 Turbo
Appreciate 0
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 07:55 PM.




zpost
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST