Gavin
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Posts posted by Gavin
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Heres why I think that approach works fine, as has been proven, but couldn't be theoretically ideal.
Well, actually, I dont know how well 1 squirt per cycle would work, but with that aside.
Although it is true that the valve is often open for a shorter period than the injector, is the injector necessarily even firing during this time? The mixture sits behind the intake valve for an extremely short period before it opens, and therefore the engine runs just fine this way. However, wouldnt it be ideal for the injector to be opening at the same times for each injector, therefore making the time between the first squirt, second squirt, and valve opening the same for each cylander? Obviously this is true (sequential injection), but the fact is with out three banks we have to make due.
If you went from one pulse to two pulses per cycle, MS would simply cut the pulsewidth in half, giving the same amount of fuel. If it does run rich, you should check your Injector Open Time value.
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Trying not to ask the forbidden question... But did you try it with the normal code?
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OK so I'll add 3/8" of washers and see how it goes. Thanks guys.
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The main advantages of Motec, as far as I am concerned (not about serious telemetry, complex variable cam control, etc.) are -
Map/Bap - Has the option of using Map/Bap(barometric) to continuously compensate for changing pressures. This simple algarithm gives a perfect representation of how barometric pressures are affecting elevation, as this is a simple function of the pressure ratio across the engine. You would be suprised how recently this was figured out. Newer versions of MS do feature this, but they dont feature....
Map/E-Map - Manifold absolute pressure over exhaust manifold absolute pressure. This not only is more accurate than Bap for N/A, it is a fabulous feature to have on a Turbo'd engine.
MAP correction - This is kinda complicated. Its basically just a different way for the computer to interpret the VE tables. With MAP correction the VE % in the table is relative to the MAP, and not barometric. This is most easily demonstrated by example, which I happen to have from another discussion.-
Heres a normal VE table -
And heres the same one, MAP corrected-
You could immagine how this helps when tuning.
Those are the main ones, asside from that it just has a great interface. Tuning it is a breeze, but honestly I find MegaTune's live tuning interface easier (and I love Motec's!).
Oh, and SEQUENTIAL INJECTION!!!!! Of course.
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Simultaneous works just fine. Smooth idle, great performance.
I will look into this later as I really want to understand why the MS alternates the injection cycles even in simultaneous mode. When I figure it out I will let everyone know the outcome.
Probably because I'm right! jk
I'm intirested as well. I'll try not to have a seizure over this in the meantime.
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Z-ya, by sequential, I take it you mean simultaneous?
I have always used alternating, and heres my reasoning.
Although you are correct in pointing out that there are three pairs of cylanders and only two banks, I dont see how simultaneous injections could occur at the same time during each cylanders cycle without six seperate squirts (btw, why not try that?). With three simultaneous squirts, each of these squirts can only occur at exhaust TDC for three cylanders and compression TDC for the other three — Thus creating the largest possible difference in the time the fuel in injected between each pair.
With alternating, a squirt will be happening at both Ex TDC and Comp TDC for two pairs of cylanders. The remaining pair would still be receiving two squirts at the same time.
Six simultaneous squirts would be the only way of being consistant across all cylanders with MS, as I see it. Am I wrong?
--- Although I guess in the case of three simultaneous squirts, the extra squirt could help to smooth things out... Whoa, this is complex. So, alternating is the only way of having the timing of the injection uniform across four cylanders, where as the three simultaneous squirts would only allow this for three of them.
So, which is better?
Perhaps it would be best to test this at the dyno day before concluding anything.
Sorry for my stream-of-consciousness rant.
---- Ok sorry now I have to add to it... And please forgive me as I may be straying farther from whats going on if I'm still confusing myself over something..
I was thinking of squirts per REV, but since its squirts per CYCLE, alternating 1-6 and 2-3-4-5 should the only way to get something remotely consistant between cylanders......
Although each cylander is ony receiving two seperate squirts over the simultaneous three, there are four squirting events going on in the engine per cycle.
Someone tell my why Im still wrong?
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It doesnt look like it from the interface, although similar.
--- Oh thats a Pantera EFI, ya I've heard of them.
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Cool. So, throw some numbers out there!
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Nice. I'm also trying to sort out how much caster I should run but am having some trouble. Right now I'm at 2.84 on either side. What are disadvantages of too much and how much is that?
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How much does a washer of a given thickness change caster?
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No, Motec is the preppy boy BMW. The price difference is in the support that comes from Haltech being produced by an actual company.
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Nice! I have some re-tuning to do!
Wanna test some SW20 3S-GTE injectors?
Have any DSM 450s lyin' 'round?
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OKOK I see the wisdom in toeing out the front.
I am so far very happy with my local shop and I'll post the info on the forum.
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Well, rrrrr, in my ideal fantasy world this is a track only car, but I'm forced to drive it till I get my Corolla on the road again (dont want to talk about that), and still I dont drive it much. Is it something I could deal with?
Just how thick do I want the washers to be in my TC rods? For how much caster? And how much do I want (bad question I know, answer that as best you can)?
And if I add a little caster after my alignment, how badly is it going to screw things up?
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Alright guys, everything is together and im going to have a shop install the ALCA bushings and camber plates tomorrow, as well as an alignment of course.
Heres what im thinking of asking for:
Front:
Camber: -2.0
Toe: +0.00
Rear:
Camber: -1.0
Toe: -0.5
What do you guys think of that?
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As of now, Baddog does not offer a 280 sub rail connector.
Man, I'd lend him my car for a pair of those. The guy lives two towns over from me...
Im seriously going to ask him.
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Ya I was making things up (nat as bad as Nissan or anything.)
Mine says 170.
I have the pinstriping, if you get to the paint stage and decide you want to go that route, holla at me.
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It says 160hp under the hood of my Black Pearl.. Less I'm mistaken.
Is yours originally black?
Heres a chart of the stock 78 L28's output:
Talk about torque!
BTW mine has been in more serious accidents than I even know about (at least three) and is still almost dead straight. You might be OK.
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Congrats!
Sounds like my car, sept on roids
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Thats about where mine hovers.
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Could you post the same datalog with the pulse-width graphed?
The obvious question, and dont be insulted—it must be asked: is the fuel pump your currently using for EFI or your old carb setup?
Do you have a fuel pressure gauge? You should rev it up and make sure its holding pressure.
I'll keep brainstorming...
- Oh hey, maybe its a spark problem resulting in an unburnt mixture that appears as lean to the O2 sensor? Just throwing out ideas.
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I have been fortunate in never having a reset problem in any of the cars Ive worked with. Aside from the filter I dono what to tell you. Maybe put the power source for MS closer to the battery? Maybe the ground as well?
Why would one 280 have this problem while another doesnt? Strange... Could it be the alternator?
For non-reset related problems, I'd be happy to look at those datalogs. Email em over to gavinwilliams(at)mac.com .
Send your .msq as well.
You do have the wideband wired into MS, right? That would be key.
Dont throw in the towel... I dont see a better option for you, except a hugely more expensive EMS, which wouldnt necessarily fix the resets, plus probably wouldnt be any easier to tune. And screw that anyhow.
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Don't know why you would, but you could...
Because its so easy to do with the mechanical ignition, and you still get to ditch the AFM. I had mine like that for some time. I have also set that up on my Silvertop 20v 4AGE powered Corolla and a Gen. 1 Miata simply by adding seperate temp sensors and cutting off the factory injector wires, with no problems (note those are all Bosch L-Jetronic ECU'd cars). But on those two it was only temporary, spark IS where its at.
Why wouldn't you use MS?
Or a better question, why would you go out of your way seeking fuel only?
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Nobody has anything to add to my suggestions? Hope thats a good sign not a bad one..
How are things going kvansic?
MS-II Simultaneous or Aternating?
in MegaSquirt
Posted
So then wouldnt it matter most when things are heppening more slowly, like at idle?
I think people who found a better idle with simultaneous perhaps did not have 1-3-4-6 and 2-5 paired together.
----- **** me! I meant 1-6 and 2-3-4-5! I thaught they were paired differently...
Im gonna edit that just to not cause confusion.
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Feel free to ignore the crazy person in the corner talking to themself, but heres what Im thinking now-
I think three simultaneous injections would actually be ideal, since the cylanders are split in the timing of the squirts, and also because there are three of them to smooth things out. However, this reduces the maximum duty cycle of the injectors. I still think two alternating squirts are better than two simultaneous because the timing of the squirts is much more uniform.