Zmanco

When I drove with gauge on the laptop showing the intake air temp, I noticed that in low speed driving on a warm day the temp seemed to average higher than when mounted in the plastic spacer. (Note: this is very subjective as I did not do back to back drives under the same conditions with the sensors in each position.) My theory is that when the VE table was tuned properly for a cooler day, the resulting much higher temp on the warm days caused MS to lean things out too much. Having the sensor in the middle of the intake manifold seems to reduce the difference in temp between the cool and warm days (probably by reading higher on the cool days), resulting in a mixture that is closer to optimum for both conditions. At least that is what I think is going on.

I believe Mobythevan did a 1-day install for Proxlamus, but he is pretty experienced with MS. If you have never done an MS install before, I think getting it drivable by the end of a 2 day weekend would be very aggressive.

Going back to your original question, i don't think there is anything cheaper than megasquirt other than remaining with your stock FI (assuming it's in good condition). But to Braap's point, the stock FI is really only good with a stock cam. As for MS, there are several versions of the hardware, and then different versions of the firmware as well. At first it's a bit confusing, but if you spend some uninterupted time on the MS website, I think it will become clear. I just went through this myself with a similar build to what you describe and have been very happy with the outcome. BTW, MSnS can be used for fuel-only and it gives you larger tables for tuning than the stock firmware. Here's a brief summary I put together while it was still fresh in my brain: http://forums.hybridz.org/showthread.php?t=122277 As for price, I spent around $800 by the time I was finished. I was starting with a carb'd 73 so had to buy things (like injectors, high pressure pump, etc) that are already on your car. My guess is you could do it for around $500 give or take $100. FWIW, I started with fuel-only. That was enough new stuff to deal with at one time. I am now getting ready to convert to letting MS control spark. I don't think that it will be all that much extra to do, just need to source the parts. That's part of the beauty of MS - you can bite it off in chunks if you want. Plus, lots of support here and on the MS forums.

Have you checked the front differential mount? That's a common thing to fail, and it fits your description of the noise. When the mount fails, the nose of the diff lifts and moves around when you shift and apply the throttle. It's much easier and cheaper to fix than the diff itself.

Disclaimer: I am NOT looking to reopen the debate on which location provides the most accurate intake air temp readings. As I've been tuning with megalogviewer, I found that sometimes it would make a lot of changes to my VE tables and other times just a few. The big changes seemed to happen when I would tune when cool, and then do another session later when hot out. Same thing when reversed. I also noticed that I had more lean-surging and hesitation when driving during the day in stop/go traffic than the evening when it's cooler. Eventually I came up with the hypothesis that the IAT is reading higher than it should on hot days and perhaps leaning things out more than it should (hot air is less dense than cool air and hence needs less fuel - all else being equal). This is with the sensor mounted in the plexiglass spacer just behind the throttle body. As an experiment, I moved it to the center of the intake manifold and have found that I'm getting much more consistent driveability from a given tune (VE table). My guess is that the air temp readings, while probably skewed high due to heat soak, are on a relative basis to each other more accurate. In other words, on a hot day, the IAT readings are raised more in line with the actual temp of the air going into the cylinders. I plan to leave the sensor in the center of the intake manifold as on my car it seems to give me the best compromise for driveability. If it was a dedicated track car, where part throttle didn't matter so much, I'd probably go back to just behind the TB. BTW, this is with the stock intake manifold from an '80 (with the webbing between runners), a ceramic coated header below it, and the GM sensor.

I switched to a ZX compressor and mounting bracket a few years ago on my 73 and it has been great. As other said, it mounts to the block with 4 bolts on the driver side down low. The mount is aluminum and weighs much less than the original Rube Goldberg contraption. I think I picked mine up at a local JY for about $25. The compressor mounts solid with no mechanism to adjust the belt tension, so make sure you get the idler pulley as well - that's how you adjust the belt.

Any secret to finding the shaft? I see the dizzy for sale now and then, but never the shaft.

http://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=85& Interesting article. Although it's clearly a bit self-serving for TireRack, if they followed the procedure as they described, even at 4/32" of tread left there is a very significant degradation of braking performance. Typical new tires have about 7-9/32" of tread so replacing tires earlier at 4/32" is A LOT sooner. And even at 4/32" the braking performance was pretty poor. Probably the best answer is to leave more distance in front in the wet!

So the NA oil driveshaft won't work? Too bad - I see the turbo dizzy for sale from time to time, but never the drive shaft.

Thanks mobythevan, that makes sense. Now to find a turbo dizzy that's in good shape

BTW, does the turbo distributor use the same base (part that bolts to the block) as the non-turbo?

Ok, as I think about this further, it dawns on me that same issue occurs with a conventional distributor using vacuum advance. As the plate in the distributor is rotated by the vacuum solenoid, there's the same issue that the rotor and electrode are no longer "perfectly" aligned when the spark is fired. I guess the misalignment isn't enough to matter and that the spark just jumps across the slightly longer path? Have I beaten the horse to death?

I have a feeling I'm not asking this question clearly, so let me try a different tack. I'll create an exaggerated scenario to make the point. Let's assume that sometimes we want the spark to fire 30 degrees BTDC and other times at TDC. I understand that the CAS sends the crank (actually cam in this case) position approximately 60 degrees in advance of the TDC event. It seems to me that in the first case the cap would have to be rotated about 15 degrees so that the electrode in the cap is aligned with the rotor. But then for the second case where we want to fire at TDC, the cap would be 15 degrees away from the rotor when the spark fired. My questions are: 1) is this indeed how it operates? 2) does this mis-alignment between rotor and cap electrode matter? (I know I exagerated to make this point - maybe using more realistic values means that the error is too small to matter?) Am I making this too complicated?

I follow what you're saying, but am still a little unclear on how the rotor distributes the spark to the plug. Are the electrodes inside the cap wider than on the N/A cap so that the rotor will be aligned with them for a longer range of rotation? I'm guessing that if I had a turbo distributor I could just look at it and answer my own questions. TIA.

I've been running fuel-only MS on my NA L28 and I'm thinking I'd like to control spark as well. It seems like the easiest approach might be to find an L28 turbo distributor which includes the CAS. I understand how the CAS tells MS the position of the crank so MS knows when to fire the spark (MSD box in this case). But what adjusts the position of the distributor cap relative to the distributor so it can deliver the spark to the correct plug? I can imagine that as long as the rotor is reasonably near the electrode in the cap when the MSD fires, that most of the spark energy will be delivered to the plug. Is that how this works? I know that the technology available in the early 80's wasn't all that advanced, so I figure it's got to be something pretty simple.

Glad to hear it's gone so well for you. You might want to look at getting an old laptop to leave in the car. I picked up an older Toshiba, loaded Windows 2000 on it, and power it from an old inverter (120 VAC) that I had. I just leave it on the passenger seat when tuning, and put it behind the seat when I park outside. The laptop was only $100. Craigslist is great for that. As you get more familiar with MS, you'll want to start datalogging and then using Megalogviewer to help adjust your tables to fine tune. There are other apps as well. Good news is they don't take a lot of computing power, so an old laptop with 256 MB of memory running windows 2000 (even windows 98 is ok) works great. Have fun!

I understand the point you're trying to make, but I think you missed something. The airbag next to us when we drive is properly installed for the application (in this case, use in the car). Plenty of other things, like explosives, pesticides, weapons are safe when used as they were designed to be used, and dangerous when used otherwise. The question at hand is what's the proper way to ship it? Those are different conditions than the car and hence the device needs to be packed such that it's safe. My guess is that a conductive (not pink poly bag) bag would good enough, but that is only a guess based on what I know about electronic components. The right answer, from those before me here, is to contact the shipping company and follow their rules. For those who said "just ship it", I'm guessing that you're still young enough that you believe you are immortal and really don't think much about those around you. I hope for your sake you gain a little wisdom before you hurt yourself or others.

Pistons aren't like wiper blades where you can just throw another set on if you don't like them. If it was me (and it was last summer) I'd do my homework a little more thoroughly before choosing pistons and rings. No info on the net doesn't mean they aren't any good (could be they are manufactured under a different brand name), but nonetheless, it's a cause for concern for me. BAP-GEON is a very reputable chain of parts stores specialized on imports. Also, ITM is sold by Black Dragon (formerly Victoria British) a reputable mail order house for Z parts. If you plan to drive hard (and almost everyone on this site does), you should care about the top ring material. If it isn't specified, it's probably cast iron. Let me say I have no affiliation with any of these organizations, and obviously it's up to you which way you go on this. But I think one of the main purposes of this site is to share accurate information, and I just wanted to make sure you had a little more before you made your decision. Good luck!

I don't know about those on ebay, but I used ITM. They include rings as well and the top one is molly. IIRC, the price was about $225. I bought through BAP-GEON in Colorado Springs. I've got about 8k miles on the engine now including several track days and have been very happy. I wanted a molly top ring and there were very few choices for the L28s.

With regard to porting the intake manifold, is there something else that can be done besides matching it to the 60 mm TB and port matching to the head?

I have a similar setup and am running MS fuel only. I have a 280zx dizzy and MSD 6AL and have no noticeable issues with spark. But, Jon's comments have me wondering if by not letting MS control spark (and vary it) that I may be missing something. Perhaps I'm not getting as much advance across the rev range as the engine could tolerate? In other words, I can never advance more than the worst case rpm. I do notice that when I add too much advance, I hear pinging around 4500 rpm. It's usually gone by 5k. I've tried richening the VE table in that region but haven't been able to go past 35 degrees total. I am wondering if I had MS controlling spark if I might be able to add some more advance above 5k? Anyone have an idea how much additional power might be gained? FWIW, I am currently running with 35 degrees total advance - all mechanical, no vacuum. PS. Hope this isn't a thread hijack as it seems to me to be a continuation of the discussion.

I have never seen flashes from under my dizzy cap, so I think you should start there. The fuel pump comes on for 2 seconds when MS is first powered up to prime the fuel system. It will start up again during cranking although you may not hear it. I would focus on the ignition issue above to start, and then ensure you have the ignition signal coming into the MS properly. You should see the RPM guage moving during cranking.

Latest update: Since I've reinstalled the LC1 with the beta firmware things have been better. At first I saw a few full rich events, but since then I haven't seen any. I think it makes things better, and if you're having unexpected resets with it, I'd recommend you try it.

There will be air trapped in the M/C. I've only done it once, but IIRC, there was a hose and fittings that came with the M/C that connected the front and rear outlets. I held the m/c in a vise, filled it with brake fluid, and then slowly pumped it until no more bubbles escaped into the reservoirs. Instructions came with the M/C. Perhaps someone else can describe it better?

So have you figured out how/where your headgasket was leaking? I don't see anything obvious from the pictures, but perhaps in person you can see something. If not, then you might want to get the head pressure tested before you reinstall it. I had an N42 develop a pin hole leak near one of the valve springs due to a casting defect. I'm told this is quite rare in L6s. I had the usual water in the oil symptoms of a blown head gasket, but couldn't see anything wrong with the head off. I would never have found the pin hole just looking for it.