psu_Crash Posted February 18, 2009 Report Share Posted February 18, 2009 So I have been working on my baby all winter and finally had a chance to get it out a couple days ago running on EDIS for the first time. Took it easy for a few miles to make sure everything is OK then romped on it. Shifted into 3rd and matted it. Tires broke loose and the the tach went from 3.5k to O $%&! REAL fast! That kinda scared me and made me smile all at the same time. Looked back at my datalog and the tach spiked to almost 7200!!! ... not good So anyways I have the rev limiter disabled in MS since I have been told it's a bad idea to have it cut fuel at high RPM when EDIS will spark at a default 10 degrees advance reguardless and possibly detonate hard. I have a shift light hooked up at 5500 RPM but it revved sooo fast that it wasn't much help. Any suggestions on how to set it up so i can avoid the chance of doing this again? Link to comment Share on other sites More sharing options...
Technology Posted February 18, 2009 Report Share Posted February 18, 2009 Get better tires. Link to comment Share on other sites More sharing options...
psu_Crash Posted February 18, 2009 Author Report Share Posted February 18, 2009 Get better tires. LOL .. yeah yeah. The tires only have about 2k miles on them! But they are just some firehawks. I needed tires and they had the size/speed rating I was looking for I may have been at a bad spot in the road, a bit of loose gravel or maybe a wet spot, but either way looking for a solution to keep me under 6k RPM Link to comment Share on other sites More sharing options...
Technology Posted February 18, 2009 Report Share Posted February 18, 2009 Well, before I toasted my motor, I hit a little bump while I was romping on it and it spiked the rpm also, though I didn't hit any rev limiter. I set mine to 7k. I would recommend a limiter at your desired rpm, but if you can, cut fuel and spark at the same time, that way you don't really have the possibility of detonation. But if it cuts fuel and not spark, it will still spark when it is supposed to, there just won't be any fuel, so the ignition system wouldn't be causing detonation. I think even with both ignition and fuel cut out simultaneously, you would run the same chance of detonating as you would with spark still going. Set it really low like 3k rpm and see what happens. Link to comment Share on other sites More sharing options...
psu_Crash Posted February 18, 2009 Author Report Share Posted February 18, 2009 I'll play around with that this weekend and see what I think. Rev it without going anywhere and watch my knock light. Then if it's half way decent outside maybe I'll take it for a spin. I'll let ya know how that works out Link to comment Share on other sites More sharing options...
mstieg Posted February 18, 2009 Report Share Posted February 18, 2009 You could toss in an MSD ignition box and put a rev. limiter in that... Link to comment Share on other sites More sharing options...
psu_Crash Posted February 18, 2009 Author Report Share Posted February 18, 2009 (edited) You could toss in an MSD ignition box and put a rev. limiter in that... Is that possible to do with the EDIS setup? Just sold my whole MSD setup when I went EDIS ... I was thinking I can probably build a frequency filter and have it cut the signal to my coil pack at a certain rpm the problem there is that it would be a progressive spark cut instead of a solid limit, or maybe hook up a relay from the shift light in MS to cut +12V to the coil pack Also thinking of changing my spark map so that at 6k RPM or so it severely retards the spark timing causing a huge loss in power. Not sure what kind of bad effects that would have though. Edited February 18, 2009 by psu_Crash Link to comment Share on other sites More sharing options...
Technology Posted February 18, 2009 Report Share Posted February 18, 2009 I actually think both of those solutions would work fine. A progressive cut is also known as a soft cut, and in my AEM, you can adjust from a really soft cut up to a hard cut. A soft cut is easier on an engine, but you will continue to rev a bit once you reach that rpm. Retarding the timing would work too, you could bump the fuel up a little bit to avoid any potential problems. Link to comment Share on other sites More sharing options...
Maxzillian Posted February 19, 2009 Report Share Posted February 19, 2009 (edited) Someone makes a circuit board for the EDIS that dumps the coil power through a resistor pack, leeching the power from the coils. No power, no spark! With this setup you can do a spark rev limit with EDIS. I'm having trouble finding the board, but I'll post a link once I do. Edit: Found it, may still be in the works. http://www.autosportlabs.net/Hard_rev_limiter_1.2.0 Details on it in their forum. http://www.autosportlabs.org/viewforum.php?f=18 My only initial concern is whether or not the megasquirt code has an output available to control that. I'm sure it can be programmed in as the megajolt is/was closely related. Edit edit: They now have kits available. http://www.autosportlabs.com/hard-limiter-module-p-36.html http://www.autosportlabs.com/hard-limiter-...mbled-p-35.html Edited February 19, 2009 by Maxzillian Link to comment Share on other sites More sharing options...
psu_Crash Posted February 19, 2009 Author Report Share Posted February 19, 2009 Thanks! That is exactly what I was looking for! I will email diyautotune and see what they have to say about integrating it with MS Link to comment Share on other sites More sharing options...
psu_Crash Posted February 19, 2009 Author Report Share Posted February 19, 2009 Well I talked to the guys at diyautotune and they said it looks like a good unit and should work fine but as far as hooking it up and getting the proper signal I am on my own. I think I ca regulate the 12V shift light output to 5V and make it work for me. For a $15 unit I figure I can't go wrong. I'll let you all know how it goes. Link to comment Share on other sites More sharing options...
Maxzillian Posted February 20, 2009 Report Share Posted February 20, 2009 (edited) Yeah, I can see that working, but you won't be able to use any sort of launch control. That is, of course, unless there's a variable you can use in defining your shift light that ties into the launch control system. (hint!) Personally I don't know off the top of my head how to go about it, but I have no doubt it can be done with a little code editing. Edit: Currently dicking around in Megatune. I'll let you know what I find. Edited February 20, 2009 by Maxzillian Link to comment Share on other sites More sharing options...
Maxzillian Posted February 21, 2009 Report Share Posted February 21, 2009 Well, I'm out of ideas. The coding for the extra code is a little above my head. Anyway, your idea with the spare ports setting will work fine as far as I know. If you want launch control, you'll need to post on the msextra forums ( www.msextra.com ) and see if any of them are savvy as to what has to be done to the program. Link to comment Share on other sites More sharing options...
psu_Crash Posted February 21, 2009 Author Report Share Posted February 21, 2009 I think I will set it up with a combination of retarding my spark map and richening my fuel map 100RPM or so before the hard rev limiter will hit from this unit. That way in essense it is a soft cut shortly before it totally cuts out the spark and fuel. I don't want to be at the point of pushing max HP and just have everything suddenly cut out, so this should ease into it a bit. Not that I plan on bouncing it off the limiter EVER but these things happen and it is a nice safe guard. Link to comment Share on other sites More sharing options...
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