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<  MegaSquirt Fuel Injection  ~  Ordering Megasquirt

PostPosted: Thu Oct 18, 2007 6:30 am
PlatinumPlatinumJoined: Sat Nov 25, 2006 9:14 pmPosts: 304Location: San Jose, California
Steve, thanks so much for the informative response!

Was your 32 mpg claim using British gallons? If it's American, that's really gooooood....

So, at this point I was thinking of buying a used pre-built box online on ebay (MS-I, PCB V2.2), building a short harness from DB37 to L-Jet, and trying megasquirt out first. I'm a little worried that after 10 hours building it, and whatever extra time and money that is spent, I may not like it. If that's the case, I"ll look in to Gotech or Motronic atleast.

But, when I do build a unit on PCB 3.0, should I get MS-1 and do MSn-E or pay the extra cash for MS-II? Common question I know, but still confusing to me.

Also, when you were tuning ignition, how did you know how close you were getting to detonation? My exhaust is loud and I'm worried I won't be able to detect pinging. It's true that you cannot use a knock sensor on these engines for some reason right?

Thanks!



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PostPosted: Fri Oct 19, 2007 12:45 pm
User avatarPlatinumPlatinumJoined: Wed Nov 24, 2004 1:06 pmPosts: 221Location: Dorset UK
Hi Grant

UK gallons for me!

Mines a v2.2 PCB as that was the newest version at the time, if you can get one for a good price, then great. Although if I did it again I'd use the latest version 3.0 as it already incorporates improvements that you'd want re reliable injector driving and such. Half the fun is building it yourself and reliablity is up to you too.

I'm using MSn-Extra and it's great, I really can't fault the functionality available. It's hard to advise whether you need the MS-11 features above and beyond the msn-e.... You have to appreciate my MS knowledge is a little out of date simply because mine works so well I haven't had to think about it for ages!

I would advise using the recomended MS box and make the adaptor pictured, it's a lot less hassle.

Re igntion tuning, starting with the factory (safe) settings gives comfort, and despite the loud exhaust you can indeed hear pre ignition... its most prone at low rpm / part throttle - which is handy as the car is quietest at that point! I used the old method of find a quiet road and advance it until you just hear pinking for literally a second, then stop and retard the timing a couple of degrees then try again to make sure all is well. PLEASE DONT do this a full throttle / big rpm as it'll hurt the engine .. I'm talking 1500 - 2000rpm part throttle just to get the transitions clean! Then you have a good guideline for what the rest of the tables can look like.

You probably wouldn't hear pre ignition at high rpm or WOT until too late, although I bet you'd hear the following BANG! Hence use the factory settings for starters, then add maybe 5 degrees at most on WOT until you can set it up on a dyno.

Interestingly whilst trying more advanced and retarded timing settings on the dyno I found that power actually started to drop off BEFORE the engine hit audible pre ignition, proving the old "butt dyno" really does work. That also kind of says that my 9.5 C/R isn't high enough for the warm cams, manifolds etc.

Knock sensors are really just small microphones that "listen" for a characteristc noise of pre- ignition and they have to be tuned per engine type. Alfa 12v V6 internals are mechnically noisy (the valve train especially) so any knock sensor would false alarm too much to be any use. Although a 24v with hydraulic lifters might be suitable - anyone agree/ disagree?

hope that helps
Steve



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PostPosted: Fri Oct 19, 2007 1:22 pm
User avatarVerdeVerdeJoined: Fri Dec 03, 2004 9:55 amPosts: 645Location: Southern California
Steve R wrote:
Knock sensors are really just small microphones that "listen" for a characteristc noise of pre- ignition and they have to be tuned per engine type. Alfa 12v V6 internals are mechnically noisy (the valve train especially) so any knock sensor would false alarm too much to be any use. Although a 24v with hydraulic lifters might be suitable - anyone agree/ disagree?

24v has knock sensors from factory.

I don't see why you can't make knock sensors for the 12v, except the home mechanic may not have the necessary development equipment and understanding to get it right.
Jes



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PostPosted: Mon Oct 22, 2007 1:57 pm
PlatinumPlatinumJoined: Sat Nov 25, 2006 9:14 pmPosts: 304Location: San Jose, California
I just bought a new MSI on V2.2 for trial use for $157. I'm pretty sure I'll have to add a fly back board and make a stim, just in case.

I hope this forum still has those old wiring diagrams for the DB37 to L-Jet sitting around somewhere.... :?



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PostPosted: Fri Nov 02, 2007 8:06 am
User avatarGoldGoldJoined: Mon Nov 29, 2004 9:59 amPosts: 182Location: Chicago, IL
grant wrote:
I just bought a new MSI on V2.2 for trial use for $157. I'm pretty sure I'll have to add a fly back board and make a stim, just in case.

I hope this forum still has those old wiring diagrams for the DB37 to L-Jet sitting around somewhere.... :?


I ran the V2.2 without the flyback for quite a while without any problems. I later switched to the high-z injectors and a custom intake. Just be very careful with the PWM setting. I can't remember off hand what I ran but it was conservative. No transistor meltdowns on the V6. Same settings toasted the output section on a 4-cyl L-jet Spider.

You will be much happier with the MSn-Extra code in an MS-I box. It offers 12x12 tables and optional ignition which you can transition to MS-II if you want to do the add-on board on a V2.2 board. Just output them in VEX format so you can import them later.

I've tried many versions of the -Extra code and I've found v020i to be the most stable. Like Steve, I tuned my MS 4 years ago and haven't really touched it since. It's been dead reliable. I get about 28mpg highway cruising at about 70-80mph. I turn the accel enrichments way down or off for long cruising. It really makes a noticable difference in fuel economy. Around town or at he track I keep a pretty aggressive fuel map and accel enrichment.

The hardest part are the WUE settings. If you don't live in a cold climate it's hard to get the low end right until you hit an ultra cold day when you find out they don't really work. That said, even guessing from the coldish settings will be sorta ok to make it idle. Don't bother with a cold air device, just tune the WUE and you won't need one.

I did mine on a -6degF Chicago winter day. The only unpleasant idle characteristics come from the cams, not the MS. My motor isn't very stock so your parameters are going to be easier than mine.

Good luck with the MS-I/V2.2 stuff. Many of us started there and can help you. When you go to the upgrade, it will be much easier.

I'd do it in this order:

MS-I/v2.2 that you have with MSn-Extra v020i with 12x12 tables (fuel only).
MS-I/v2.2 MSn-Extra adding spark
MS-II/v2.2 add-on board/chip translating your MS-I tables to the new chip
MS-II/V3.0 board upgrade. Just build the board and plug in your MS-II chip with settings.

-Peter


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