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      05-11-2015, 03:24 PM   #23
bigbrian
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Quote:
Originally Posted by Sharif507 View Post
i actually found out elsewhere, it seems the boost doesnt really increase, since they are maxing out with the stock tune already at about 23 psi.
The stock tune runs at 16-17psi. I measured the boost by tapping into the charge pipe, putting a gauge on it from the dyno, and doing several pulls on the dyno. If the boost is as 23psi w/ the AMS tune that is a ~7psi increase over stock.

Where are you getting the 23psi number from?

Brian
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/// 2o13 m6 f13 . jb4 tuned . meth injected . msr intake . 21" adv1 wheels . eisenmann race w/ catless DPs . vorsteiner full aero . accuair e-level w/ bagged KW V3 struts . dinan sways . bel stir+ w/ alp jammer . jl audio subs
/// 2o13 x5m e70 . velos tuned . 22" adv1 wheels . dropped on kw variant3 coilovers . passport 9500ci radar & jammer. gets groceries fast
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      05-12-2015, 06:49 PM   #24
chask
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Quote:
Originally Posted by Sharif507 View Post
i actually found out elsewhere, it seems the boost doesnt really increase, since they are maxing out with the stock tune already at about 23 psi.
Does anyone actually know what the maximum stock boost is? I cannot tell you how many different figures I have heard for this. I have seen posts on N54Tech with people saying as low as 11-13 psi and on other forums with others saying 15 up to 18 psi. I think I read or perhaps heard somewhere that it was 21 or 22 psi though I do not remember where that was. And now it's 23 psi. I also have heard directly from BMS that the "OEM tune is 18 psi peak and 15 psi at redline."

I remember a Volvo presented a paper at the SAE International Exposition (Society of Automotive Engineers) about 30 years ago on a turbocharged engine they built. To further improve vehicle performance it would allow a brief peak boost then it would drop back to a constant safe maximum boost level. It would overshoot the normal maximum boost by about 3-4 psi for a few seconds to help get the car moving then drop back to a steady state level that the engine could sustain long term. For example, when you floored it the ECU would permit say 18 psi boost for about 3 seconds then roll it back to 14-15 if you maintained WOT. It would also reduce boost (and ignition timing) if the engine knocked and if I remember correctly coolant temp or intake air temp got too high (may not have those last two right - it's been a while; this was like 1981-82). The point is that control strategies like these can confuse people who are trying to see something specific about the maximum boost the engine is running. If the control strategy varies the boost it would depend on when you looked and what was going on with the engine at that particular time. As all M drivers know, things happen extremely fast with these cars. It's pretty much impossible to follow several engine parameters at the same time you are driving the car - don't try it (I think it's asking to have an accident). You almost have to have some sort of logging device or be running it on a dyno with full instrumentation. I'd certainly recommend the dyno route.

As I understand it there is some variation in boost level with RPM and other engine parameters - I don't know for sure what they are mapping boost on but I would bet knock for sure and perhaps some temperatures (intake air, coolant, oil), gear selection, and possibly others too. But IMHO anything over a few psi variation in the maximum boost level is pushing credibility. Of course, there could be more if something potentially harmful to the engine was happening - they would obviously cut the boost to 0 psig (or whatever the wastegate spring is set to) if the engine was knocking or over overheating so badly it was about to give. There is absolutely no way the variation in maximum boost is 10-12 psi from one stock engine to another. I do not know who is wrong but this is just weird.

Please don't take this as the absolute truth as I am just now reading about the BMS system and have no experience with one. Whatever the stock boost is, people on the N54tech forum with the BMS tune are saying they are running a 2.25 psig increase with 93 octane gas up to 3.0 or 4.0 psi over stock with 100 octane and/or methanol on a N63/S63TU motor. Those numbers are also shown in the BMS configuration instructions for their Stage I tune on that same site. If the stock numbers BMS provided me are correct, with their tune you can see a peak of between 20 and about 21-22 psi boost depending upon the octane you are running (or octane boost) and other mods. That does not seem unreasonable - it's not inconsistent with the power levels they are getting, not to mention the performance users are seeing.

I don't know anything about what the various flash tunes are doing. I guess they could do about anything boost wise that the engine and the range of the MAP sensor would permit. I have read that some engines have a 3.5 bar MAP sensor. Assuming the first bar of that for naturally aspirated operation, that would leave the capability to run 2.5 bar boost (by my calculations that would be a little over 36 psi). I also know firsthand that it's no easy task to reprogram an ECU for performance mods.

Has anyone actually hooked up a pressure gauge to the compressor outlet or intercooler outlet or to the intake manifold to directly measure the pressure?

I'm still interested in seeing some kind of performance figures for this AMS tune. I do not see anything about it on their website yet.

Quote:
Originally Posted by bigbrian View Post
The stock tune runs at 16-17psi. I measured the boost by tapping into the charge pipe, putting a gauge on it from the dyno, and doing several pulls on the dyno. If the boost is as 23psi w/ the AMS tune that is a ~7psi increase over stock.

Where are you getting the 23psi number from?

Brian
I did the above working offline and just posted without checking the thread for changes. This 16-17 psi sounds more reasonable to me.
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      05-12-2015, 09:45 PM   #25
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Quote:
Originally Posted by chask View Post
I did the above working offline and just posted without checking the thread for changes. This 16-17 psi sounds more reasonable to me.
For each increase in number you set the BMS to it increases total boost by approximately 1psi. The car runs 16-17psi stock (with BMS set to 0). Running at +4 on BMS brings it to 20-21psi. This was measured with a gauge hooked to a bung welded into the MSR aluminum charge pipe while car was running under load on the dyno.

I would be interested to hear what boost the ECU tunes are running at. I assume they can run safely at a higher boost level as they have additional variables they can tune vs. simply increasing boost.

I want to say m6beast is running BMS at +7 with methanol squirting into the engine. I would be a little reluctant to run it that high but I will definitely move it up to 5 and "maybe" 6 once my methanol is flowing.

Brian
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/// 2o13 m6 f13 . jb4 tuned . meth injected . msr intake . 21" adv1 wheels . eisenmann race w/ catless DPs . vorsteiner full aero . accuair e-level w/ bagged KW V3 struts . dinan sways . bel stir+ w/ alp jammer . jl audio subs
/// 2o13 x5m e70 . velos tuned . 22" adv1 wheels . dropped on kw variant3 coilovers . passport 9500ci radar & jammer. gets groceries fast
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      05-21-2015, 06:25 PM   #26
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Quote:
Originally Posted by chask View Post
Does anyone actually know what the maximum stock boost is? I cannot tell you how many different figures I have heard for this. I have seen posts on N54Tech with people saying as low as 11-13 psi and on other forums with others saying 15 up to 18 psi. I think I read or perhaps heard somewhere that it was 21 or 22 psi though I do not remember where that was. And now it's 23 psi. I also have heard directly from BMS that the "OEM tune is 18 psi peak and 15 psi at redline."

I remember a Volvo presented a paper at the SAE International Exposition (Society of Automotive Engineers) about 30 years ago on a turbocharged engine they built. To further improve vehicle performance it would allow a brief peak boost then it would drop back to a constant safe maximum boost level. It would overshoot the normal maximum boost by about 3-4 psi for a few seconds to help get the car moving then drop back to a steady state level that the engine could sustain long term. For example, when you floored it the ECU would permit say 18 psi boost for about 3 seconds then roll it back to 14-15 if you maintained WOT. It would also reduce boost (and ignition timing) if the engine knocked and if I remember correctly coolant temp or intake air temp got too high (may not have those last two right - it's been a while; this was like 1981-82). The point is that control strategies like these can confuse people who are trying to see something specific about the maximum boost the engine is running. If the control strategy varies the boost it would depend on when you looked and what was going on with the engine at that particular time. As all M drivers know, things happen extremely fast with these cars. It's pretty much impossible to follow several engine parameters at the same time you are driving the car - don't try it (I think it's asking to have an accident). You almost have to have some sort of logging device or be running it on a dyno with full instrumentation. I'd certainly recommend the dyno route.

As I understand it there is some variation in boost level with RPM and other engine parameters - I don't know for sure what they are mapping boost on but I would bet knock for sure and perhaps some temperatures (intake air, coolant, oil), gear selection, and possibly others too. But IMHO anything over a few psi variation in the maximum boost level is pushing credibility. Of course, there could be more if something potentially harmful to the engine was happening - they would obviously cut the boost to 0 psig (or whatever the wastegate spring is set to) if the engine was knocking or over overheating so badly it was about to give. There is absolutely no way the variation in maximum boost is 10-12 psi from one stock engine to another. I do not know who is wrong but this is just weird.

Please don't take this as the absolute truth as I am just now reading about the BMS system and have no experience with one. Whatever the stock boost is, people on the N54tech forum with the BMS tune are saying they are running a 2.25 psig increase with 93 octane gas up to 3.0 or 4.0 psi over stock with 100 octane and/or methanol on a N63/S63TU motor. Those numbers are also shown in the BMS configuration instructions for their Stage I tune on that same site. If the stock numbers BMS provided me are correct, with their tune you can see a peak of between 20 and about 21-22 psi boost depending upon the octane you are running (or octane boost) and other mods. That does not seem unreasonable - it's not inconsistent with the power levels they are getting, not to mention the performance users are seeing.

I don't know anything about what the various flash tunes are doing. I guess they could do about anything boost wise that the engine and the range of the MAP sensor would permit. I have read that some engines have a 3.5 bar MAP sensor. Assuming the first bar of that for naturally aspirated operation, that would leave the capability to run 2.5 bar boost (by my calculations that would be a little over 36 psi). I also know firsthand that it's no easy task to reprogram an ECU for performance mods.

Has anyone actually hooked up a pressure gauge to the compressor outlet or intercooler outlet or to the intake manifold to directly measure the pressure?

I'm still interested in seeing some kind of performance figures for this AMS tune. I do not see anything about it on their website yet.



I did the above working offline and just posted without checking the thread for changes. This 16-17 psi sounds more reasonable to me.
Quote:
Originally Posted by bigbrian View Post
For each increase in number you set the BMS to it increases total boost by approximately 1psi. The car runs 16-17psi stock (with BMS set to 0). Running at +4 on BMS brings it to 20-21psi. This was measured with a gauge hooked to a bung welded into the MSR aluminum charge pipe while car was running under load on the dyno.

I would be interested to hear what boost the ECU tunes are running at. I assume they can run safely at a higher boost level as they have additional variables they can tune vs. simply increasing boost.

I want to say m6beast is running BMS at +7 with methanol squirting into the engine. I would be a little reluctant to run it that high but I will definitely move it up to 5 and "maybe" 6 once my methanol is flowing.

Brian
I got the M5 560 HP non CP, it boosts 15-16 psi. With BMS +3, it goes to 18-19 (sometimes 20psi at redline).
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