Chris Brown wrote a pretty good book on the subject called "How to make sense of squiggly lines". He goes over this topic in light detail, mostly to give a starting point.
The viscosity of fluid plays a big part in it's pressure variation. Oil probably isn't going to show much at all under 100 hz, but I have seen meaningful data over 100 hz with fuel.
For temp, it's all about the sensor, and what it's mounted it. Some sensors can take 2-5 seconds to show meaningful change, others will show change in fractions of a second.
For fluid temp, it's usually 1hz updates. For air temp, it's 10 - 25 hz. Pressure sensors are usually useful at 25 hz, above that is "scientific". Lambda is more to do with mass flow over the sensor....at low engine speed you might get useful updates averaged over 1-2 seconds. Then at higher engine speeds, you might see a sensor top out at 20 hz. Beyond that, I know there are some that claim to be faster, I haven't seen meaningful change from sample to sample.
I'm just curious.
All the key parameters have an RPM safety limit. Because of how low I set the RPM limit, the engine essentially feels like it get's shut off once a parameter is exceeded. So far I've experienced this for fuel pressure, over boost, and coolant temp.
The knock settings I've got are so conservative, I'm pulling upwards of 10 degrees on an event trigger. (It's scales with event severity) I'm honestly not certain I even have knock happening most of the time....as the solid engine mounts cause a lot of feedback from the chassis/transmission. Once I change to poly mounts, and get on the dyno to play with full spectrum ignition trim, I should be able to see what's really going on.
Edit: I'll show all the warning systems shortly. You can set a different RPM limit for every warning type.
Last edited by PEI330Ci; 08-10-2017 at 01:32 AM.
Warnings that can control engine speed....looks like I missed to expand oil pressure and crank case pressure....
Last edited by PEI330Ci; 08-10-2017 at 12:31 PM.
Do you have a way to quickly cancel the limit?
I just feel that for a street car, such low limits might not be ideal. I can think of plenty of situations where you might need some power fast and if the car is basically in limp mode, it might be tricky.
Any specific reason why the fuel pressure limit is at 1500 RPM and the others are at 2000 RPM?
If the limits are setup properly, you shouldn't need to cancel them. Too often I've seen people bypassing safety systems, with horrible results. You can setup 2 steps of warnings however, where the first level notifies of a threshold being exceeded on the Motec Dash.
The only warnings that I have the ability to reset the result of instantly, is on the PDM.
Regarding the RPM limits: There are numerous versions of code and tunes that have been merged together with the package I've shown. Normally, I've had everything set to 2000 RPM which allows me to limp the car around. The 1500 Rpm for the fuel is likely an artifact from an earlier setup file.
What happens in practice when these RPM limits engage is that the engine feels like it has been turned off. It really catches your attention! Once, I had the fuel pressure low limit set too high, and when I closed the throttle on the 1-2 shift at the drag strip, the vacuum in the inlet manifold pulled the FPR down below this limit. I was then thrown into the seatbelt when engaging the clutch into 2nd!!!! I've since setup the fuel pressure warnings based on manifold pressure....
This is the kind of stuff I'm talking about. Now what if that happens while you're merging onto the highway or passing someone on a two lane road with oncoming traffic?
Yes I am being dramatic, but an accident happens so fast - we both know this very well.
I was just wondering if you had an override button ''just in case'' you needed to make a quick move.
Will the limit cancel itself once the parameter goes back in the acceptable range?
There is a delay function, where the parameter must be false for that period to activate. The same delay is applied to deactivate in most cases, although there are some that have independent values for each.
On the race track, I remember this complaint about power cuts. It would unsettle a car mid-corner leading to an off. IIRC, the solution was to cut a little bit off the top of the RPM range so the driver knew something was off, rather than kill 80% of the rev range.
This might be interesting to you:
https://www.youtube.com/watch?v=4QF5...7&spfreload=10
Last edited by PEI330Ci; 08-14-2017 at 01:25 AM.
Btw i want to say thank you for your detail on the electrical work. Nothing like drooling over $250 wire strippers haha.
Capital Driving Club Car # 102
How to turbo your car:
Step one. Install ecu and learn to tune and or have it tuned.
Step two. Install injectors and retune.
Step three. Install turbo parts and bits. get it running with out leaks. DO NOT DRIVE IT. Idling should be ok
Step four. Retune car
Step five enjoy
Think ill pick up one or two when they go on sale. Buddy needs a set too.
Capital Driving Club Car # 102
How to turbo your car:
Step one. Install ecu and learn to tune and or have it tuned.
Step two. Install injectors and retune.
Step three. Install turbo parts and bits. get it running with out leaks. DO NOT DRIVE IT. Idling should be ok
Step four. Retune car
Step five enjoy
The right tools make the work so much more enjoyable!!
I've seen that. I don't really agree with the relative assessment of how critical it is that the FPD has to be exactly tuned to the peak excitation frequency of the system to get a benefit from it. The FPD adds a large degree of compliance to the system, so while you might not get a perfect reduction of the peak response, just adding the compliance of the damper will see a huge reduction in the amplitude of the peak.
You need to do the FFT/tuned damper thing if you are really trying to reduce down a specific frequency, but you'll typically introduce new peaks due to higher order harmonics of the system, but just adding compliance gets you a huge amount of peak amplitude reduction on a very rigid system that's being excited by some external source (fuel injectors, hydraulic actuator, solenoid valves etc).
Do you have a nice hot glue gun?
This guy picked up some F1 parts after the Manor bankruptcy, their wiring loom looks like an elementary kid's art project compared to yours.
https://www.youtube.com/watch?v=7SDUy-b3uTA&t=707s
Lots of cool sensors too. Do you see anything you find interesting?
His point was to find the source, not to apply a band aid.
I have FFT capability in i2 Pro.
Higher order harmonics typically have lower amplitude.....also, I don't follow how a damper will add higher frequency energy into the system.....unless it was an active device?
I've seen that.
I can assure you there is a reason why that "messy" stuff is there. They don't do anything that adds even 0.1g without some validation.
Those sensors look pretty sweet. I'm tempted to email him asking to buy 10.
Last edited by PEI330Ci; 08-15-2017 at 03:34 AM.
Measuring the system is the easy part - building a damper with the target natural frequency is the hard part.
Anytime you put a mass-spring-damper in a system, you'll change the natural frequency response over a large part of the frequency spectrum.
The important part is that you're putting a large degree of compliance in the system whereas most fuel systems with lots of aftermarket hose and/or hardline have very little compliance relative to the step-change pressure input amplitude the injectors are putting in. Maybe you still have an issue after fitting a fuel pressure damper if the forcing at the natural frequency is really severe, but I'm thinking it'd mostly go away, or at least reduce down in peak amplitude to a level that won't cause a noticeable issue in tuning.
Been there, done that, got the t-shirt. Sometimes you need to get super fancy with a custom tuned solution, but often times it's a matter of just putting some compliance in the system and calming things down.
Something I was looking at today:
Where is this pressure sensor located? I don't think I remember you ever posting a picture of it.
Been a hectic week of tuning, wrenching, and driving the car.
VANOS control is now really solid.
The VE table is really close to Lambda target.
Boost control I'm running right now without any PID. (Just feed forward settings)
Vehicle speed is functioning again, so I now have gear detection, and boost by gear setup.
The knock detection and control strategy is dialled in, as well as numerous other safety features.
Probably the biggest change was dumping 5 gallons of 114 Octane race fuel into the tank mixed with 91 octane. I've moved to a much more aggressive timing map (GSGunni's), which made a huge difference everywhere. I then dialled back 5 degrees of timing everywhere, and increased the boost target to 130 kPa. (About 19 PSI)
Then I setup the nitrous system, with a small 25 jet but with low (650psi) bottle pressure. So I've probably got a 15 shot? Anyway, I'm using it for spool from 2500 to 4000 RPM....but that lead to the next road block.
I've got some kind of feed problem on the fuel side. It's not there all the time, but on occasion when the turbo is spooled up, I get fuel pressure dropping from 73 psi down to about 64 psi. One pull it will do it, (The ECU adjusts injector Duty Cycle which covers it up) the next the fuel supply is stable.
Before I run a 50 jet (or bigger) to spool the turbo any more, I need to figure out the fuel system.
Tomorrow I'm picking up the Surge tank after I found a crack in the top that was the source of my fuel system leakage/smells.
So the surge tank will go in, and the A1000 fuel pump will go back in. That should give the fuel pressure needed......
I also have a few things for the car that I haven't talked about yet:
Which box is from Armstrong Race Engineering?
1996 332IS
Built 3.2
CES/Steed TS Precision 6466, spraying a "$π!℅" load of meth.
Technique Tuning 80# tune.
1/4 mile 10.84 @ 136.72
Your 1 and only stop for all your BMW performance needs
WWW.CESMOTORSPORT.COM
Bookmarks