M42club.com - Home of the BMW E30/E36 318i/iS
DISCUSSION => Engine management => Topic started by: JiXer on December 12, 2007, 10:47:51 PM
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I will be doing a DASC (Downing Atlants Super Charger) on my e30 318iS and I want to use Megasquirt for Engine Management.
I was hoping to find a similar write up from someone who is boosting approx. 7 PSI and running megasquirt.
My main concerns are things like choice of air temp sensor, crank position sensor and pulse wheel, beginning fuela/spark maps, etc.
I figure there is a write up somewhere on here, but I wasn't having much luck finding one. I can also get on r3vlimited and e30tech if someone knows of something there.
Thanks in advance for the help.
J.
http://www.bigfishmotorsports.com
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your best bet is to just read what grassroots motorsports did to theirs and copy it. Megasquirt isnt going to get you much above the hp they got if you even match it, and you have a much greater chance of blowing your motor because of tuning
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i don't agree, especially with the bit about blowing your motor. Megasquirt would be a very good solution, and standalone management is the way to do things properly. Clearly with the grassroots motorsports car they had a lot of trouble with mapping, and a full standalone would be a good solution, as long as you're prepared to put the work into it.
I'd say you're much more likely to blow your engine on the factory ECU, esp with factory timing on a blown engine, and with all the modifications it would require to the fuelling, cahnging the fuel pressure etc, than with a full standalone solution with wideband lambda feedback and AFR targetting based on it's output. The megasquirt will ensure that the engine is fuelled correctly, timed correctly and as a feedback system when coupled with a wideband lambda/knock sensor will ensure that you don't run lean and don't run any det etc., meaning your engine is much better safeguarded against blowing.
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My main concerns are things like choice of air temp sensor, crank position sensor and pulse wheel, beginning fuela/spark maps, etc.
You shouldn't be too worried about this. You can use the standard 60-2 wheel no problems, likewise with the temp sensors if you calibrate the megasquirt. For base maps, I can help you for a standard M42, although you'd be well advised to have a go from scratch yourself. Once you have the car idling correctly then you can make a good estimation of a workable map, then with some testing on load you can get pretty close, and use autotune/megalogviewer to help you hone the map further to help you understand how to get it perfect. I think the real heads up that you'll need will be getting the map perfect, which is much mroe difficult than getting a good map - acceleration enrichment, for instance, is tricky to get right.
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I don't have any experience with the DASC, but plenty with megasquirt.
I would suggest just starting with fuel, and using the stock ecu for spark until you have a workable fuel map. (I am not sure if the ecu will do this, someone with more experience with the stock ecu might be able to tell us)
I am also a huge fan of MS2 vs MS1.
I haven't put too much though into MS on an m42 application, but I do know that all the required elements are there and useable.
Also, you NEED a wideband, and I would set that up before switching to MS, get it up and running on the car in the NA stock setup. I don't know of anyone using the JAW, but it sounds competent and cheap.
http://www.14point7.com/JAW/JAW.htm
Do you plan on running water/meth injection with MS?
I use MS2 v3 on our superflow dyno engines and MS1 v2.2 on our RX-7 race car.
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good link in that thread above, never seen the JAW wideband! thanks. I've not been 100% happy with my LC1, but it is nonetheless an invaluable tool. Why are you so much of a fan of MS2 over MS1? I run MS2 but I also think MS1 extra code is really strong, feature packed yet stable.
If you keep the AFM, there's no probs using Motronic for spark and MS for fuel.
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I really like ms2 because of the accuracy. every aspect of it is that much better. MSnS for 2 is questionable, and I havent used it yet. but for testing engines on the dyno the precision is amazing, especially on forced induction applications.
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I don't think MS2 extra is questionable at all imo, although the betas have many more features than the release. It's interesting how much our opinions and experiences differ, the precision has made negligable difference in the cars I've tuned! I found MS1 extra to HR code gave a little difference however.
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I think fuel tests on an engine dyno where you can measure every variable and alter them is a completely different situation than using it in a car. I can't go into detail on what I do, but we are making power on some pretty crazy fuels.
The only reason I said MS2 extra was questionable is that I haven't used it nor did I know anyone that has, but now i do.
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... since I started this post and I hope you guys are still out there as I am finally am getting around to doing this build.
Couple of updates on me and how this thing is going together:
I have now built and set up a few different engine management systems for a few cars including a Megasquirt for an M20 stroker. I did the whole thing from scratch and though it took a while, I did learn a lot. One of things I've learned is that I would pay money for a quality MS timing table to get my tuning going. Fuel tuning is a piece of cake if you know where you want your AFR, but the timing is still a mystery to me.
So if anyone has a boost timing table or more specifically, one running a DASC, I would be stoked. I know that would not be a turnkey thing for me, but a good starting point is key.
All that said, here is the set up I am going to run (I call it an M43 :)
- M44 motor (head, pistons, rods - all stock)
- M42 Crank
- Compression Ratio should be around 9.3:1
- Boost Target = 12psi (stock 5.75" crank wheel & 3.4" pulley)
- M42 front cases, cam sensor, 60-2 crank sensor, throttle body & TPS
- M44 knock sensors
- Megasquirt (fuel & spark) running off of MAP with 42# Hi-Z injectors, full length headers, & 3" exhaust
Where, oh where do I begin with timing. I DO NOT feel comfortable with even trying to start the car off of one of the MS generated maps. No way.
I have started a series of posts below that outline the basics of setting up the file. Most of this is based on what I just did for an M20 motor, but it is all subject to review by others and I haven't (REPEAT - HAVE NOT) run a motor on this file yet, so please don't take any of this as a sure thing just yet.
J.
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Megatune 2.25 - Specifics:
Engine Constants:
Required Fuel: 7.2
- Displacement: 1900cc
- Cylinders: 4
- Injectors: 42 lb/hr
- AFR: 14.7 (gasoline - in my case 91 octane)
Injector Characteristics:
(Delphi 42# High Impedance)
- Opening Time: 1.2ms
- Battery V Correction: .2
- PwM Current Limit: 100%
- FIdle Threshold: 160°F
- Baro Corr.: off
Injector Control
- Control Algorithm: Speed Density
- Injections per Engine Cylce: 2
- Injector Staging: Alternating
- Cylinders: 4
- Injectors: 4
- MAP Type: 250kPa
- Engine Type: Even Fire
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Megatune 2.25 - Specifics:
Using Innovate LC-1
- Sensor Type: Wide Band
- EGO Switch Point: 2.352
- Ignition Events or msec per step: 31
- Controller Step Size: 1%
- Controller Authority: 10
- Active above CLT: 140°F
- Active above: 1,400 RPM
- EGO Corr. Step Counter: mSec
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Code Type
Distributor: off
Neon/420A Decoder: off
Wheel Decoder: Generic Wheel
EDIS: off
TFI Ignition: off
HEI Ignition: off
The following is subject to your hardware set up.....
Input/Output pins
Fidle Function: Idle Control
LED17: Spark A
LED18: Spark C
LED19: Spark B
Multiplex Ignition: Normal
X2 JS0: Fan Control
X4 JS2: Output 1
output3/Spark D: Spark D
pin10/ shift/Spark E: Shift Light
knock in / Spark F: Knock input
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Base Teeth: 60
Second Trigger Enable: This is where things get ify for me. The last motor I did was an M20 which does not have a crank sensor. Is this where you would enter it in to the equation?
2nd Trigger Active Edge: ????
2nd Trigger Missing Teeth: ????
Missing Teeth: -2
And thats where I get stuck. Does anyone have this figured out? I will verify it once I have the pulley system back on and TDC set, but I want to know what others have come up with.
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Clueless. Someone gave me the numbers for the M20, so I never even really read about it.
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oops
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One of the VR sensors is the cam and the other will be your crank. I think the crank is the base, and the cam is the 2nd, but it might not matter. I do not have specific #'s for the trigger wheel but I am sure someone does, or you can count them. As for spark, just make a conservative map up to 100kpa, then have them drop off as boost. You will want less advance than a turbo car, because of the lack of intercooling. Look at what the m50/s50 people are doing for advance, and copy it but more conservative at higher MAP. you can always add in more advance once it runs.
Hope this helps
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OK this is why I still don't have megasquirt :D lack of info about settings on m42/4 and lack of tuners in my area to solve my doubts :(
There are a few here with MS, waiting for their answer.
Try to send a PM to http://www.m42club.com/forums/member.php?u=27 . he has MS2 extra on his M42 :D
Do you have the m44 engine wirings? You calibrated stock sensors or you bought GM ones?
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Do you have the m44 engine wirings? You calibrated stock sensors or you bought GM ones?
Yes. I have a full m44 wiring harness and will run it all the way through the firewall and make my splices to the Megasquirt harness there.
One of the VR sensors is the cam and the other will be your crank. I think the crank is the base, and the cam is the 2nd, but it might not matter.
Yeah, I don't think you need to worry about the second one. It should just run off the crank wheel and not need the second one for anything.
I do not have specific #'s for the trigger wheel but I am sure someone does, or you can count them.
Yeah. I'm sure I can figure it out. Just haven't gotten around to it. Figured the info was out there.
As for spark, just make a conservative map up to 100kpa, then have them drop off as boost. You will want less advance than a turbo car, because of the lack of intercooling. Look at what the m50/s50 people are doing for advance, and copy it but more conservative at higher MAP. you can always add in more advance once it runs.
Yeah, again, I figure there is better info out there than that. Hoping others will chime in.
J.
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OK, so here's an update. Got the math wrong on the coil firing, but the concept was the same. As a group, they would fire 14,000 at redline.
Individually, it would be 3,500 as opposed to stock which is 1,750.
However, in talking with Matt at DIY, there are some issues with getting the MS to run sequential ignition. I have never done it before; always ran wasted spark. So, I don't know much about it.
Matt gave me these choices:
1. Use two coil outputs and a wasted spark coil pack - this is a very well proven setup.
2. Modify it for four coil drivers that fire in wasted spark - simple to wire up, but one we haven't tested for ourselves. Most people who have run this setup apparently don't have very much trouble with it, though I have seen occasional reports of setups like this having trouble starting in very cold weather. (Usually these reports come from Scandinavian countries where the winters are pretty brutal.)
3. Modify it for four sequential coil drivers. This would require a cam sync input and consequently would make for significantly more expense, plus the second VR circuit is not easy for us to bench test out.
#2 seemed like the route to go as I have the 4 coil drivers.
#1 isn't an option b/c I don't want to over work the coil drivers at high revs
#3 is preferred, but he makes it sound sketchy
I am new to this one, so if anyone can point me to some info, other posts regarding it, etc. I would be stoked. There isn't as much M42 info out there on MS set ups.
J.
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OK, so here's an update. Got the math wrong on the coil firing, but the concept was the same. As a group, they would fire 14,000 at redline.
Individually, it would be 3,500 as opposed to stock which is 1,750.
However, in talking with Matt at DIY, there are some issues with getting the MS to run sequential ignition. I have never done it before; always ran wasted spark. So, I don't know much about it.
Matt gave me these choices:
1. Use two coil outputs and a wasted spark coil pack - this is a very well proven setup.
2. Modify it for four coil drivers that fire in wasted spark - simple to wire up, but one we haven't tested for ourselves. Most people who have run this setup apparently don't have very much trouble with it, though I have seen occasional reports of setups like this having trouble starting in very cold weather. (Usually these reports come from Scandinavian countries where the winters are pretty brutal.)
3. Modify it for four sequential coil drivers. This would require a cam sync input and consequently would make for significantly more expense, plus the second VR circuit is not easy for us to bench test out.
#2 seemed like the route to go as I have the 4 coil drivers.
#1 isn't an option b/c I don't want to over work the coil drivers at high revs
#3 is preferred, but he makes it sound sketchy
I am new to this one, so if anyone can point me to some info, other posts regarding it, etc. I would be stoked. There isn't as much M42 info out there on MS set ups.
J.
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OK. here's the update on the cam sensors:
M42 = VR
M44 = Hall
The upper timing cover from the M44 and M42 are different and I have to use the M44 cover to match the head.
So, the M44 upper timing cover has the hall sensor mount on the intake cam and utilizes a plate mounted to the cam gear (see image below) to trigger it.
I have removed the M44 cam gears in favor of my nearly new m42 cam gears and I confirmed that the trigger plate will mount to the M42 gear. I do know that I CANNOT mount the M42 VR sensor to the M44 upper timing cover as it sits too far in and the sensor contacts the cam gear. So, changing over to the M44 hall sensor seems to be the only option.
I also know that the intake cam gear on the M44 is slightly different and I don't know if it matters. The one I have isn't in that bad of shape, so I think I might swap them simply to avoid it as a potential problem. There seems to be a slightly different profile to it which might effect how closely the sensor comes to the spinning plate. Not sure if a hall sensor is that sensitive, but I know VR sensors can be.
So this puts me in a place where I can run sequential ignition. Now I just need to read up on how to make it work.
Thoughts anyone?
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hello! sorry for delay onyl just got your pm, not been on here much, lost interest in my car as my new engine is noisy and still using oil from cyl 4, so i need to do some work over christmas. just been driving it an ignoring issues for a while until I have some energy to fix it.
As for MS, I run WS on the original coils, I'd recommend doing this yourself as a starting point, is a straightforward setup that works well. Then you don't need to worry about the cam position sensor at all. I always intended to start WS for simplicity and go sequential ign at some pt, but I started using MS maybe 2 and a half years ago on my M42, and haven't ever felt the need to change from WS, it works great.
As for trigger settings, I can't remember 100% if there are 19 or 20 teeth past the missing teeth at TDC, i'm pretty certain it's 20, though for some reason I have it in my head that I have 114 degrees set in my MS2, suggesting 19! Next time I have my megasquirt fired up I'll check for you, I have MS2 extra though and so work in degrees rather than teeth. What code are you using? What other questions do you have? Feel free to let me know and I'll gladly assist.
Tuning - for safety make sure you enable IAT based retard and use it aggressively when first running the car. Use a map deliberately too retarded when first running the car, use the best fuel you can too. Also start off running your map too rich rather than too lean. Use EGO feedback if not feeling confident. Start off by tuning idle, then revving and holding rpm to get a feel for other rpm values, then start tuning some light load sites at low speed, you'll start to get a picture of what the map will look like by doing this and can make estimations for other sites. Datalog and use megalogviewer to help your understanding, it's a great tool. If you follow the above and make sure you've read the megasquirt docs etc, you should have no reason to worry about running the car on megasquirt. If it's not too late already, set up megasquirt on the standard engine first, then add SC, then retune megasquirt.
Additionally, if your car is still running on Motronic, what I usually do is do some datalogging with MS T'd into the crank sensor, and make sure that on the datalog you have a perfect VR signal under all RPMs and all conditions. A good stable crank signal is critical to getting a great tune.
that was a bit meandering, feel free to hit me with some specifics! Also feel free to send msqs, datalogs etc
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Interesting thread. I plan on a very similar build. Purchased a small sc and will be taking advantage of an electric clutch to turn on and off the supercharger. I've been reading the mega manual site for the past three mornings (gettng the car ready for paint in the afternoons) some very knowledgable folks around here. My question is about signal integrity. Is there a spec on maximum harness run from the sensors to the ms unit and back? Are some of the marine installs using long harnesses like that?
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bump, you guys ever sort out the tuning with these?