barf

more tuning theory links:

http://www.streetrodstuff.com/Articles/Engine/Detonation/

http://www.gami.com/articles/bttfpart1.php

http://www.magnecor.com/magnecor1/truth.htm

http://www.motorsport-developments.co.uk/stus.html

http://innovatemotorsports.com/resources/rich.php

http://www.max-boost.co.uk/max-boost/ignition_deeper.htm

here are some links on tuning theory i found:

http://www.daytona-sensors.com/tech_tuning.html

http://www.honda-tech.com/showthread.php?t=1060267 (LOL people tune Hondas?)

http://www.innovatemotorsports.com/forums/...ead.php?t=10210

http://books.google.co.nz/books?id=ze_w0i3...;q=&f=false

with regard to MBT; there is only one ideal time to launch the ignition event, for any given combination of variables. im not as experienced as some here, but afaik if you are adjusting timing to extract more power, then rather than increasing the power output, you have just yet to find the ideal or correct timing.

the reason ignition is advanced in the first place is that the peak energy conversion (deflagration) occurs latent to the ignition event, the piston should be on the power stroke in otto engines at this time (advance majorly considers time to reach peak energy conversion) otherwise should the fabled detonation (an explosion; which is the opposite of a deflagration aka 'burn') occur, the piston could be forced in reverse direction.

* detonation is detonation

* combustion is a deflagration (subsonic)

http://en.wikipedia.org/wiki/Deflagration

2 / 2 successful installs here, in e30s with m20b23 and m50b25. using MS2 with v3 PCB from diyautotune.com MS2Extra firmware

here is some more links for reference, or those interested:

MS2 Extra manual: http://www.msextra.com/doc/ms2extra/

MS2 Spark Map tuning: http://www.msextra.com/doc/ms2extra/MS2-Ex...l.html#sparkmap

Choosing spacing of RPM and MAP bins correctly for your application: http://www.not2fast.com/efi/spacing.shtml

yo rds, jumping on your thread.

that spark map was done by calculation with an Excel spreadsheet (anyone interested in a copy?) - it's also a conservative estimate and not going to be perfect! major paramaters in the function are:

* valves per cylinder

* bore size

* RON

* squish and quench

good squish/quench in the m50b25 head and spark plug located centrally; so more retarded timing than a 2-valve per cylinder head, for example. maximum advance on newer heads (and pistons) is lower than old heads due to better flame front kinetics.

anyone going to sponsor the dyno time? :-P

summit road on the port hills is just a big dyno with corners isn't it? can't test the barometric altitude correction on a dyno-meter.

what approach do the tuners on here take to spark map adjustments once you're on the dyno?

after the weekend can report the Innovate LC-1 wideband Exhaust Gas-Oxygen (Bosch) sensor worked a miracle for the tune. lowered coolant temperature, smoother and faster with AFR looking smoother and smoother with thanks to the VE/AFR live analysis feature and 'target AFR' tuning mode now switched on. post up that spark map rds?

This thread is almost 2yrs old since last post

and still relevant.

computers are only as good as the tune in them, with exception for features and etc

sensor on camshaft aswell as flywheel will be req'd for cam-sync for the wasted spark, distributor would certainly be easier ;-)

also for safety (scrutineering requirement) is to have fuel pump controlled by computer (ie only when engine is running), even with carbeurettor i assume.

spot on camb will need 3 spark outputs from the megasquirt to two plugs each (assuming firing order), like skyline yes

thanks will but i understand perfectly

the megasquirt can control spark and fuel, indenpendantly of one-another providing you know what you are doing, or do i give bmw owners too much credit?

http://www.diyautotune.com/catalog/megasqu...-unit-p-65.html

I reccomend tying your fuel and spark management together whatever you do. I reccomend Megasquirt-II for this it worked well for me but i'm a sparky ;-)

MS-II features with latest firmware are beyond all other product, good prediction algorithm for engine angle. when fuel injecting, X-tau compensates for wall-wetting in cylinders. RAM and NV flash memory so can change tune without re-flash while engine running. cannot reccomend bmw computer for tuning but link and motec also are good. megasquirt spark control is based from MAP/MAF-or-any-combination-of, TPS and advanced measurment of engine speed and accel/deceleration.

ONE THING: they are not plug and play - you will need to learn ALOT, there is no plug it in and drive with 500hp button. the result from megasquirt depends of skill with eletric system and tuning as seperate matters.

your engine is very new, the factory timing source should always be used where possible and could be one or two variable reluctor pickup - mine on m20b25 is in the flywheel casing it is a toothed wheel with one tooth missing which usually denotes a TDC. the coil-on-plug system poses challenge does the unit have built in ignitor module? (i only have old bmw) the MS2-Extra firmware should suit your purpose with some work req'd to install new VB921 drivers on spare outputs but angle input(s) if no built-in-driver (ie low-tech coil-on-plug) but should be simple if you have a skilled engineer to do the work.

not many in NZ doing Megasquirt installs that I know of, I would love to help but i'm in christchurch and barely even get time to tune mine. good luck with the project hopefully there are some simpler solutions offered

sorry you probably know how already but what I did was change the req_fuel until idle torque was OK then modified the VE table using the built-in table generator to increase HP and torque if I increased req-Fuel and use lower HP/torque when reducing req_fuel to keep the difference between full vac and atmosphere in line with the base/req_fuel value, its a tricky job without all these pro=tuner o2 sensors, smelling the mixture is a close second though ;-)

try turnin off accel/decel enrich and x-tau if you having trouble tuning it caused me issues cos i have tps switch (ie either 0% or 100% throttle) and so hitting TPS100% would cause mixture change to be too drastic

req_fuel is most important setting and you can throw out VE table by changing it, what req-fuel do you use? what is your VE table's 3d shape like?

so how is the tuning going ? it took me long time to get mine under control, i always had issues with accel enrich....

it's going good bro! no o2 sensor so tuning by the seat of my pants. the old '85 fuel system called for a slightly higher than calculated req_fuel I've settled on 19.1 now initially I calculated at 3bar top-rail pressure 16.3 should work.

can;t be bothered (ie i work too much) getting a throttle sensor so fuelling is controlled by only RPM and manifold air pressure but very smooth and shortened my intake plumbing and removed the barn door so improved rpm control with considerable power off idle still. have yet to control spark with the MS2 but that will happen as soon as i suss out a decent trottle position sensor! i'm missing out on heaps of MS2 features like X-tau correction and TPS-based accel/decel mixture correction so really need a TPS before going much further, need o2 sensor aswell but not until it's dyno time.

are there any other bmw or jap throttle position sensors that fit up to the m20b25 throttle body instead of this dumb switch thing they have?

i need Variable Resistor/potentiometer type (not switch)

for VR (magnetic type) up to 100-150 ohms should be OK. they are just a coil of wire.

the sensor on the front balance wheel is not used by the ECU, only for diagnosis connector. ECU uses a sensor in bellhousing.

VR sensors are incredibly reliable i would investigate other things first.

well it got me to work and home twice!

having a problem with it stumbling or juddering under decel approaching idle speed. any megasquirters experienced with this?

other than that, even without a proper TPS it's far more driveable than the turd ECU it had! I highly reccomend megasquirt! not for the uninitiated though, you gotta be handy with an o-scope and/or know whats going on.

cheers mike. got mine to idle comfortably but lean this afternoon - a long way to go still.

I've wired it onto the back of the original ECU connector loom but added power circuit. factory air temp and coolant temp are both negative temp coefficient. the injectors fire in two separate banks on mine. at the moment, i'm taking timing from the tacho (coil negative) just to get it on it's feet, until I find a VR to fit into the bellhousing.

the front one?? or the one in the bellhousing??

thanks for the prompt reply!

I can only see the diagram for '89 325 there which I already have found at http://shark.armchair.mb.ca/~dave/BMW/e30/

thanks for the link!

hey mops, i'm megasquirting my '85 e30 323i what did you do to lock up the centrifugal advance or did you not spark it with the MS?? or have a post-face-lift engine??

stock ecu in old m20-series has a TPS that is a switch not a potentiometer so I wouldn't even bother unless your engine is disposable. spark timing probably too advance for FI also.

if you have I'd be keen to hear from you!

I've installed my MS2 but tuning is no easy task, maybe i'm getting my hopes up but would someone have a .msq or VE-table they could share? still havn't got mine started but maybe later today after I get rid of this stupid TPS switch thing.

how many cc/min or lbs/hr do the stock injectors claim to do?

what req-fuel value did you use?

what's a suitable TPS replacement (one that isn't a bloody switch)?