zercs280zx

'Close' to original.... looks good (dirty in this pic)

I've always wondered the same thing. If someone knows, please chime in. I've heard that high duration 280 + causes too much overlap and can effect vacuum, which is important to maintain in an EFI system. I don't have any accessories, I just need vacuum to get a MAP reading for Megasquirt and a dizzy ref (Fuel-only), so I'm wondering how high you can go or what is recomended. Is this only a issue for stock EFI systems or can Megasquirt adjust to high duration and high lift cams? Any one running ~.500 lift, 280 + duration cam in an L28 NA with Megasquirt? Full build: Lonewolf intake, ported and shaved P79 with a 3-angle valve job. Thanks.

PM sent.

I'm not familiar with this setup and always thought there had to be some kind of ignition control unit after MS for a fixed signal. A direct output to the coil (sounds like Spark control) and Fuel Only seem contradictory, but I could be wrong. Hopefully someone else can explain how it works. You sound like you've done your share of research and have a good grasp on things, so you should be in good shape once you get this ignition output setup correctly, or if it already is, figuring out what is happening to the signal. Good luck.

Icarus, Your Megasquirt board was modified to run FUEL ONLY and was setup for an aftermarket ignition box, such as MSD or Crane, only. I know because I did the mod so that I could run my Crane HI-6 ign box with my MS1 v 3.0 board. I'm not sure if this configuration will allow you to run the CAS and the dizzy. I believe that when your Megasquirt box has been modded like this, only an ignition box like MSD or Crane will accept this signal. That's what is being sent via Spark A and perhaps the dizzy does not recognize it, but you see the LED flashing. I believe that if you want to control Spark or send a signal to the CAS and the dizzy, you would have to reverse the mod and setup Codebase and Output Functions and choose the proper Ignition setup. Here's what the Codebase and Output Functions, in Megatune, look like for FUEL ONLY/Megasquirt does not control Spark: Spark Inverted = YES in Spark Settings and Dwell Duty to Fix - 50% and LED17(D14) to SparkA output. If you want to use the CAS and the dizzy, check in the MSNS manual as to how that configuration should be, and again, I do not think your board is setup correctly. http://www.msextra.com/manuals/MS_Extra_Ignition_Hardware_Manual.htm#msdout If you have any questions, feel free to ask. Good luck with your project. Eric Spark Output Wiring Diagrams. MSD output wiring diagram for a V3.0 PCB Set Spark Inverted = YES in Spark Settings and Dwell Duty to Fix - 50% and LED17(D14) to SparkA output in Codebase and Output Functions. V3.0 PCB

I have the shims, check your PM (presonal messages). Eric

Just noticed.... these pistons are for use with L24 rods... interesting. I'm not sure of anyone running this setup, but the added stroke wouldn't hurt - something to look into. good luck, mate

Good deal. Owner is great, I've done business with him: http://arizonazcar.com/piston.html

I'm about to finish up my build and I have some questions of how to handle this PCV line out of the block.... I have an L28 with a custom intake and EFI (the previous setup had the PCV line going to the OEM intake, my custom intake does not have this input). I found a line that I can tap into in the Throttle Body (after the flap, from the bottom). I was planning on plumbing the PCV hose there and let the gasses get sucked into the intake (like it was). Is that a suitable location? I would rather not drill into my intake if I didn't have to. Also, does this system require a PCV valve or can the hose just dump in there? Are there any other ways to run it? I don't particularly like the idea of recalculating these gasses back into my engine, but it seems like the best system and from what I understand you need vacuum to ventilate the gasses. FYI: My valve cover is being ventilated into a small K&N breather.

Do you mean the ignition module mounted next to the distributor (not the coli)? If you are using an MSD or aftermarket ignition box, it replaces the plastic ignition module on the distributor. If it's a 280ZX distributor, you remove the ign module and tap right into the green and red wires... I think that is what you are referring to. Also, for the tach adpater adapter, I believe you use the MSD 8920 for current/pulse ignitions (for Tachs on the '73 or later) and the 8910 on the old points systems (Tachs that came prior to '73). At least from what I researched... I'm in the process of wiring up my car

According to the msextra manual, you should run your MSD off LED17(D14) to SparkA. How you mod your board depends on v 3.0 or 2.2 (see the link below). I believe Fidle will work, but this is what is recommended. I have a Crane box and jumped my v 3.0 as the directions indicate, but I have not gotten it up in running. Some one may want to chime in, but I assumed that if the manual calls for this as the ignition output for an MSD, or an other aftermarket ignition, it's probably the way you would want to go..... it sets the dwell at 50% and Inverted through this specific output, I'm not sure what Fidle will give you or how reliable it is.... in other words, I went with the msextra manual... http://www.msextra.com/manuals/MS_Extra_Ignition_Hardware_Manual.htm#msdout

Thanks for the response, z-ya. I'll stick with 1.0 ms as the opening time. I'm still confused though. The MS tuning manual does say to adjust the PWM Threshold Time, not the opening time: 1. Start with: PWM Time Threshold = 1.0 millisecond, and 4. Move on to adjusting the time threshold. Lower the time threshold by 0.1 milliseconds at a time until the idle quality deteriorates. 5. Then increase it 0.3 ms. 6. Now, repeat these steps (starting at #2). Adjust the duty cycle and time threshold alternately to get the optimum values for your set-up. You will converge on a set of numbers that work well for your set-up. Use PWM time threshold values greater than about 1.5 to 1.7 milliseconds only with great caution – it is possible to burn out your injectors! Should I set the PWM Threshold to 1.5 ms in the Constants? I've seen a few Contants pages (that have been posted with 280zxt injectors) that are set to 1.0 ms... so, I'm not exactly sure. Thanks for your help. zercs

Thanks for the great info. Quick question... I'm using the 280zxt injectors and they are listed with a 1.5 ms PWM threshold. The MS Tuning guide says to start with 1.0 ms and that 1.5 ms and above is risky for burning injectors out. Should I use 1.5 ms as the value in the Constants? I was assuming so, but the Megasquirt info is vague.

http://www.courtesyparts.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=11044-91MM2&Category_Code=s30_nismo_headgasketL28

http://www.thezstore.com/page/TZS/PROD/PEM06/10-2139

Matt, thanks... I'll try the Crane Tach Out to the MS tach/trigger in. I'll toggle the different settings on MSnS and see if I can pick up the signal. If I can avoid resistors and jumping wires, I'll be happy. I'll report back in case anyone else is using a Crane or MSD box... thanks again.

I don't mean to go off the topic, but I have a question regarding the Trigger Input for my setup. If anyone knows how this should be wired, I'd appreciate it: MS V 3.0 MSnS for Fuel Only (wanted 12X12 VE tables) 81 ZX Dizzy (CAS) Crane H-6 Ignition Box I think I have pretty much everything figured out (output out to the Ign box and to the dizzy)... the "MS1 Extra code Ignition Hardware manual" specifies the Output setup to an Ign box very well...... my question is, if I'm running fuel only, do I have to go through all of these steps to setup the Trigger Input goping to the MS box? If so, how? I was not sure, because I am not using my MS or MSnS to control spark.... does anyone happen to know how it should be set?

Mario, Thanks for the quick reply.... that's what I figured... I already have the MS-I v3.0 box, so I'll go ahead and load MSnS-Extra on it.... I already found out how to set it to control fuel only... so I'm set, for now... Thanks!

I'm getting ready for my Megasquirt I/v3.0 install and I started messing around with the latest version of MagaTune v2.25. Yeah, I know, for anyone who I've spoken about Megasquirt, I'm behind schedule... but getting there... finally finding some time.... Anyway, I was under the assumption that it was using 12X12 VE tables, but they are only 8X8. I'd like to take advantage of the 12X12 VE table (fuel/air) for optimal tuning, especially since I plan to go wideband 02. Do I need to incorportae the MSnS_Extra software in order to upgrade to 12X12 VE tables? I do not plan on controlling spark, I have a Crane ignition box already (purchased well before deciding to go MS). Is there another way to upgarde to a 12X12 fuel/air VE table for Megatune v2.25? If I add MSnS_Extra, is it easy enough to 'turn off' spark/ignition control? (I would assume so). I'd appreciate it if anyone had any suggestions. Thanks.

I read that too quickly, I was thinking filter.... my pcv is threaded into the valve cover... one of mine broke, so I had to back it out... what exactly do you want to replace it with? It still acts like a pcv, right? It's not just a straight tube going to a filter, right? I wasn't sure there was an alternative to the old oem pcv valve... let me know if you come up with anything....

K&N model: 62-1340 If you want something different, or to compare to, the dimensions on that model are: 5/8" flange.........2" Filter diameter...........1 1/2" height it has a rubber bottom and chrome top... I found it at summitracing

I'm going to try that.... I'm swapping the oil pumps now... keeping comp inner and the old standard on the outer.... I'll follow up and report how I make out... could be awhile before I fire her up... still got lots of work to do... thanks for the tip!

I posted my reply and then had a thought... does the na stock pump in a 81 280zx use the same two springs as the turbo oil pump? Can I take the springs out of my old na oil pump and put them in my new turbo oil pump, in place of the new comp springs it came with? That would be a great option... just didn't know the compatibility of the two... thanks for reading my two overly-descriptive replies... just wanted to be clear

I'm about to swap in a new turbo oil pump with comp springs... I have a feeling the comp springs are going to be too aggressive (I have stock internals and stock oil pan, and I'm adding a slightly shaved, port and polished head with a fatter cam and custom intake on top)..... and my question is.... where can you get the standard springs? I looked around and Courtesy Nissan only seems to have the comp springs for sale and I can't find a vendor who sells the standard ones... I'd like to pick up the standard springs if the oil pressure's too high (having a feeling so)..... shoulda done my research first, but got a bit anxious in during the parts buying phase... sht happens...... anyone know who's got the standard springs for sale? Hope to get all these mods (and a couple others) in place overr the next several weekends.... then I'll mess with Megasquirt and turbo injectors......... right now I'm like a lil kid on xmas eve