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Discussion Starter · #1 ·
Seeing as though the search function didn't pick up "DI" like I wanted... I'm starting a thread.

Background: My turbo is a biggun, and the distributor *barely* clears. The cap hits the exhaust housing. No room for a heatshield. I am going ahead with MS fuel control. I figured, perfect time to install DI...?

Option 1:
From the little I've read so far, it looks like MS can operate DI in what is called "wasted spark" mode, which fires two cyl at once. It also looks like the max RPM DI can handle is 9000 RPM, which is cut in half with wasted spark mode (4500 RPM). Or something (?) I know there's more than one version of MS, and perhaps the later version can run DI... Need some help in this department.

Option 2:
Also I understand that the bosch fuel system is separate from the ignition system... There have been people who installed DI/APC on their c900s and didn't touch the fuel system. So perhaps if I could not get MS to work with DI, I could use MS for fuel control, and DI/APC for ignition and knock detection... yeah? Seems like a lot of work, but... This option would work.

Option 3:
Lastly, I *could* slot the manifold bolt holes to the limit, file down the exhaust housing and/or the distributor cap, increase the fudge factor and use the distributor. I might be able to fashion some sort of flexible heat shielding... (?) I know there are companies that make turbo "blankets" that fit around the housings. Ideas here? I am concerned about the distributor internals failing.


Please advise guys.
 

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Discussion Starter · #3 ·
Thanks. I was thinking one of these:


Plus ceramic coating the turbine housing. Anybody done this? I'm sending out my dp and wg dump to get coated so doing the turbine housing wouldn't be that big of a deal.
 

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See, this is why Raul shouldn't be banned, he would actually be able to help.

If it were me, I'd stay away from option 3, if for no better reason than the stock c900t ignition timing/distributor setup sucks balls. If you do option one, could you use some sort of aftermarket DI setup? I'm sure such a thing is available, and has been documented by megasquirt users on that MS forum. Option 2 sounds like a PITA, and it may not be as adjustable as option 1, or so I would think. You'd want to be able to re-advance the timing after peak torque, and things of that nature, and I'm not sure if stock saab DI software does that, I really have no clue.
 

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Discussion Starter · #5 ·
I agree with you. Option 2 would be a huge pain and I'd be stuck with stock ignition and a boost controller I couldn't tune.

I haven't bought my MS box yet, so if the later version could run DI I'll pick up that one.

I sort of wanted to do one thing at a time (fuel then ignition) which is why I wanted to stay with the distributor initially.
 

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The DI/APC route seems best... IIRC you just pull the DI/APC system off an early 9000 turbo, it is standalone, you may need a sensor or two.

But at least you get knock detection/spark control. With MS you just get the APC LED pin hack to cut fuel/boost.
 

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DI/APC wont work. it needs the LH box to function, so you'd be right back to square one. if you want to run the DI with MS you can use MS1 just fine, just have to use the extra code and make some hardware mods. however it should be easier to do it with the newer (v3.0) hardware, again you can still just use the MS1-extra code, or MS2 if you want, but Raul is the only one (who claims) to have ms2 running on a c900, so you would kinda be out on your own. in order to do this though you would need at the very least a crank position sensor, the c900 doesnt have one. you can get one off a 89+ non turbo car that should work though. i'd say you should just make up a heat sheild for now, until you get MS figured out, then do the ignition. you are really adding an extra level of complication by doing ignition and fuel all at once.

Paul
 

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Agreed, get the fuel working first, get the wideband working, do some tuning runs with a helper while doing some dataloging, and then once that's all dialed in get the ignition working.
 

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Discussion Starter · #9 ·
if you want to run the DI with MS you can use MS1 just fine, just have to use the extra code and make some hardware mods.
So are there examples of this done?

i'd say you should just make up a heat sheild for now, until you get MS figured out, then do the ignition. you are really adding an extra level of complication by doing ignition and fuel all at once.
Exactly... There's no way I want to have everything apart all at once. I want to have fuel installed and tested before hacking into the ignition stuff.

I think I may have found the reason why my dist doesn't fit... but I have to make some measurements first.
 

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I have also had dreams of running a DI casette but it seems like its not the ideal situation. I am sort of tempted to set up Ford's EDIS but to be honest I'm a little rusty on what all is needed to run it. It's probably very similar to DI except you wont have a 4500rpm rev limit. Sorry I can't be of more help right now, but check out Keith's site as he has some info on it, I've got to get back to skiing:cool:
 

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4500rpm rev limit would totally blow. i'd rather have a shitty distributor than such a low rev limit!
 

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Discussion Starter · #14 ·
KeithG had DI running with MS1, and now with MS2

http://ys3al35l.googlepages.com/saab

Details are here, but you'll probably need a bit more about the hardware changes, so best pm him, he's on saabcentral, and maybe this forum also.
Looks like he built a cam-position sensor, and is using that along with a crank position sensor. Note the line coming out of the dist blank plug:


I'm thinking this is definitely over my head for the time being. I'll shoot for squeezing in the dist and keeping it while I get fuel setup. Then depending on how I feel, DI might be a possibility.

Perhaps I can commission keith to build me a cam position sensor like his ;)
 

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i would be more inclined to take a file to the dizzy cap for the time being.

try it on the exhaust housing. really, try it. you might do a bit more than scratch the surface after 10 minutes of heavy filing.

yeah, 4500 rev limit would suck balls. with the ELH, you might spool a bit sooner than 4k, but i would not expect too much.
 

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from what i understand the 4500rpm limit is mostly theoretical, it should still work above that, but probably will have a pretty short lifespan compared to if you ran it the way it was designed to be used. that said, i dont think ill be using the DI with my new endeavor, there are simply cheaper coil packs that can be used that should be more reliable. the only reason to use the DI would be if you could use the information that it has available (knock sensing, ion sensing to determine what cyl to fire without a cam sensor) and at this point MS just isnt set up to work with it. I'm probably going to use either the Ford EDIS or GM DIS ignition, both are very available in any junkyard, and very well documented by other MS users.

Paul
 

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Discussion Starter · #17 ·
i would be more inclined to take a file to the dizzy cap for the time being.

try it on the exhaust housing. really, try it. you might do a bit more than scratch the surface after 10 minutes of heavy filing.
Yeah, I considered filing down the exhaust housing. Not sure how thick the casting is, and how that would effect the strength of the unit. If a file doesn't do it, I can use some power tools :shock:
 

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Yeah, I considered filing down the exhaust housing. Not sure how thick the casting is, and how that would effect the strength of the unit. If a file doesn't do it, I can use some power tools :shock:
scary.....don't go too far!
 

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kieth runs MS on DI by using the "extra" hardware, this suports coil on plug (COP) which works fine with DI.
 

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Been kinda lurking this thread for a while and I'm kinda curious:

If the DI with the MS has got these limitations (lost spark, etc.), has anyone considered using GM's individual coil-on-plug set-up re: LSx engines? Not as pretty perhaps, but I'm wondering if it might be more flexible (?).

Along those lines, I understand the LQ-9 version of those engines' coil-pack (Cadillac Escallade Iron Block version) has a hotter spark than those found on the LS1/2/6 (Corvette, GTO, CTS-V) due to the higher torque they're designed to generate. MSD also has an upgrade coil-pack as well, but for the money, I'd prolly go with the LQ-9 between those two.

Just a thought.
 
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