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BMW 3-Series (E90 E92) Forum
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The Basics of Tuning and Timing
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03-01-2011, 10:05 PM | #199 |
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That would be my theory.... and it would explain a lot.
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03-01-2011, 10:11 PM | #200 |
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From what I saw, the is table limits were decreased to compensate for the higher load/boost.
I am curious though what the ECU's compensation mechanism would be, if it has one, if it could recognize that boost/load had been increased instead of being "blind" as you called it from the dummy signal. |
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03-01-2011, 10:19 PM | #201 | |
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I think load targeting could have some repercussions as well, as Cobb is doing, working with the stock DME logic. If the car has a pre-existing condition, it could cause the car to boost well over intended levels, to hit the load target. I actually know someone who was sustaining 16.5 psi on 93 octane on his Cobb OTS Stage 1 map. Situations like this are rare, but entirely possible if the flash tune can't detect this pre-existing condition. I am not certain if it is possible to write in an actual boost limit (since the DME does indeed read pre-TB boost), I'm sure it's a possibility. What I am excited about is the possibility of integrating methanol safeties similar to what the piggybacks offer, as we can then tune for methanol injection instead of using it as an additive. I don't see it happening, simply because, where would the flow sensor output go? Perhaps there is an unused DME input that we could hijack using a patch cable from a piggyback PnP harness for the flow sensor that Cobb could possibly implement for progressive meth? A man can dream...
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03-01-2011, 10:22 PM | #202 |
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Im willing to bet the 335is and 335i share the same exact timing maps. Keep in mind the stock ecu is set up for 180 load, the 335 runs 130ish falling to 105, 14psi on the 335is would put it in the 160 range, if you notice from the timing table, 160 load has obviously lower timing.
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03-01-2011, 10:53 PM | #203 | |
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My theory exactly.
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03-01-2011, 11:12 PM | #204 |
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I think load targeting could have some repercussions as well, as Cobb is doing, working with the stock DME logic. If the car has a pre-existing condition, it could cause the car to boost well over intended levels, to hit the load target.
I actually know someone who was sustaining 16.5 psi on 93 octane on his Cobb OTS Stage 1 map. Situations like this are rare, but entirely possible if the flash tune can't detect this pre-existing condition. What might be this pre-existing condition? |
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03-01-2011, 11:35 PM | #205 | |
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03-02-2011, 01:14 AM | #206 |
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Another question I have regarding load targeting vs PID-based boost control -
Will there ever be a fix, per se, for these cars with undesirable throttle trimming and/or boost overshoot at the WOT event onset? I believe what Shiv stated regarding wastegate stiffness being different in each and every N54 holding water. I am not sure if this is something that can be addressed via ATR, but I don't think anyone here can disagree both throttle trimming and/or boost overshoot is a bad thing. Granted, many of us would like to run a custom tune created through ATR (or even the Procede, from what I understand, is capable of doing) but I guess a few questions remain. FYI - I have zero tuning experience. I just read and soak up as much information as possible.
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03-02-2011, 07:00 AM | #207 | |
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03-02-2011, 07:07 AM | #208 | |
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I remember when the FC-datalogit came out and PFC map swapping was rampant. BOOM. That's when I bit the bullet and had the FD professionally tuned. |
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03-02-2011, 07:11 AM | #209 | |
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03-02-2011, 07:25 AM | #210 | |
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03-02-2011, 08:10 AM | #211 | |
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It is too bad some of the guys who think we are hating through creating these discussions to enlighten people how the rest of the world follows tuning theory. I brought up EFI University which does a ton of training for professional tuners and enthusiasts. A friend of mine from Haltech USA used to instruct a lot of these types of courses. I am happy to see that some people are catching on and able to see through some of the BS that is spoken. This platform is itching for a tuning solution that is complete. By the looks of it COBB will be first with ATR unless Shiv actually opens up the Halwin software for people to tune. I personally don't think the end of motors will happen when ATR is released. Just as BMS is doing - the users will be able to rely on the stock DME to protect them. I have seen first hand as in developing software for this platform we tested the effects of lean burns, and timing errors, etc. The DME is very fast and very capable. That backup/safety logic is great to have - just not to use as a primary means. |
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03-02-2011, 08:23 AM | #212 | |
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This is why I am excited for atr. I will not be tuning my car myself, I will leave that to the experts. |
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03-02-2011, 10:45 AM | #213 | ||
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Although each employ timing tables, as well as a plethora of compensation values for things like knock correction, IAT's, ect. My bet is that by playing with targeted lambda (fuel), boost and the timing tables I can make a much smoother curve than would be achieved with an OTS map. I used my old STI as an example because I just happened to have a couple of my old dyno graphs laying around that were on the same dyno with smoothing set to 0 with the same 2000-7000rpm scaling, but in reality, most of the experiences I've had have shown that a car's torque curve can typically be made a bit smoother with a good custom tune. They're releasing new firmware versions for the JB4, but it is fully functional, so I would suppose we would have to define "being developed". Quite a few tuning devices come out with constant firmware revisions (Cobb AP's included on numerous platforms), so I suppose that would be based on how you want to look at it. When I dyno'd on the JB4, IIRC it was on the firmware it shipped with, which was either their 2nd or 3rd firmware version for the JB4 if I'm not mistaken. However, they've come out with a couple new firmware releases in the last couple weeks. I would say "no", the hardware is in final production and for sale to the public as a whole, however it appears that Terry is still making minor adjustments as time goes on to firmware, which is to be expected, and will likely continue on and off for while. Although, I do plan on doing a comparison of that JB4 firmware version map 1 to their autoPID map on their latest firmware version release. The goal is to improve the curve as well as the consistency of the vehicle through custom tuning and to display the results. On the majority of the cars I've worked with in the past, I've typically been able to improve peak power/torque as well... but we'll see how much is left on the table compared to these OTS maps when I start playing with it. I'm looking forward to the challenge to say the least
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03-02-2011, 02:07 PM | #214 |
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This is continuing to be a very interesting thread and I’m just now catching up on the reading. Some comments:
First, the table produced by Terry compared to the Cobb posting is very different. I have NOT seen any evidence of the DME raising timing above the 10 to 13deg at >120 units of load. Now his table doesn’t have these load values, but in comparing the 2 can would be concluded that timing would be considerably higher. Like mentioned, maybe a secondary table for limp mode. In my experiences in logging, I could make the claim that there is no timing compensation with IAT… I know this goes against all other platforms. Themyst, you mention a flash may NOT be good with certain "pre-existing conditions", but this would be the same with a piggy targeting boost instead of load. I believe the DME has some reaction to DC... too high or too low... this should be the case with a flash also. I have read that piggies have some method to "piggy" off these DC limits also. |
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03-02-2011, 03:20 PM | #215 | |
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the average tuner will show some discretion when reaching the limits of octane and timing, and you can "feel" the car pull back on you, u can also feel a mis-fire if you are well aquainted with the engine in question. that level of expertise does not come by reading or examining a product review -- it comes solely with experience. there quite a few incidents that the car is pulling timing due to combustion problems, but are side-stepped as adaptation or otherwise -- high speed surging -- and most guys that are not familiar with tuning will think its just an anomoly that will go away -- and guess what? it does, becuause the DME took care of the problem by degrading the timing curve. so this extremely smart DME now allows errors (misjudgements) in tuning, saving the engine for another battle against detonation -- if you dont know there is something wrong, you cant fix it. now those who do have the expertise can do the same thing, and say "ah ha!" -- i need to back the timing down, look at my fueling, assess the load range and make adjustment accordingly. the will look at the TPS signal, and possibly have a reliable EGT to make sense of the whole equation. if not integrated into the actual toolset, who is going to invest in a $500 Fluke meter to monitor voltages and resistance? im not against novice tuning, but i hope that when this task is taken on, there is preparation for the task. its fun, but costly to make a mistake -- and relying on the DME should be the last resort for any tuner. |
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06-27-2011, 01:14 PM | #217 |
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Great thread, I didn't realize this was stickied. All newbies to tuning need to read this before they purchase "x" tune.
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Last edited by Syndicategt; 06-27-2011 at 02:04 PM.. |
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06-29-2011, 09:06 AM | #218 |
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Great read. Definitely a must read before you buy "X" piggyback or "X" flash tuner. I come from the 03-04 mustang cobra world (cough cough). All about live dyno tuning and proactively adjusting timing for your specific application.
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08-22-2011, 07:55 AM | #220 | |
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Siemens MSD80/81 control logic
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http://www.google.com/patents?id=zox...ed=0CCwQ6AEwAA The original patent was filed in Germany in 2002. Based on typical R&D cycles (four years to commercialize a new mechanical engineering invention), I have a sneaking suspicion that some of the N54 control logic may be described in this patent. Let me know if anyone finds this useful and I'll send links to BMW's patents on turbocharging (if any). |
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