R0N Posted May 23, 2002 Share Posted May 23, 2002 What I just witness a 240Z using a 300ZXT ECU and 300ZXT MAS with all the L28ET Hardware and wiring harness. I know, sounds like a Jim Wolf setup. WRONG... The only modifications done are on the 300ZXT ECU, grounding one of the pins on the 300ZX MAS and connecting the fuel pump directly to battery. No mods to the harness nor distributor or the fuel injection wires. NOTHING disconnected execpt for the one wire that goes from the relay to the fuel pump which now is powered directly by the battery. Although he didn't drive the car I notice the car was much more responsive and idled a lot better then before. Idle was never an issue but just seems more quieter now. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted May 23, 2002 Share Posted May 23, 2002 I cut my 280ZX harness to shreds, but I didn't crack the case of the Z31 ECU. Different path, same result - that ECU really knows how to stroke the L28ET the right way. Quote Link to comment Share on other sites More sharing options...
R0N Posted May 23, 2002 Author Share Posted May 23, 2002 SleeperZ, I knew you had the z31 ecu but didn't know how you approached it. Just curious, what mods are you running on your car? Injectors size, turbo size, how much boost, fuel pressure etc? Quote Link to comment Share on other sites More sharing options...
JoshB 240Z Posted May 23, 2002 Share Posted May 23, 2002 Ron, I believe we met at the Rio Vista and MSA shows. I have a blue 240Z turbo minus the intercooler. I took a 300ZXT harness and 280ZXT harness apart and made some wiring changes in order to run the 300 MAS and ECU. I wired the fuel pump in so that the ECU controlled it, it's safer that way. This all was pretty easy to do and made my engine run a little better than the stock 280ZXT setup. While I had the harness apart I removed a lot of the extra wires that I did not need and cleaned it up a little. My real reasons for doing the swap were that 300ZXT parts seem to be easier to find in the junkyards around the Bay Area and I like the less obstructive design of a hot wire MAF than the door type AFM. Josh Quote Link to comment Share on other sites More sharing options...
R0N Posted May 23, 2002 Author Share Posted May 23, 2002 Hey Josh, I remember you. I talked to you breifly at the MSA show. I had no idea you where running the 300 ECU. You guy's make it sound so easy when rewiring it. All the post I've read on installing the z31 ecu sounded like a nightmare. Just curious can you put a Jim wolf chip in there even thou the chip original programed for a 300zxt car? Quote Link to comment Share on other sites More sharing options...
JoshB 240Z Posted May 23, 2002 Share Posted May 23, 2002 I don't know about putting the JWT chip in the ECU. I would think that you could place the JWT 300ZXT ECU in the car once the wire harness is retrofitted but I'm not positive. I do know that I am not running all of the sensors that the 300 came with so I am not sure if that would have an adverse effect when the JWT ECU was swapped in. I am not currently having any problems running the car without them. The wiring really wasn't all that difficult. I took the 280ZXT pin out and matched it with a 300ZXT pin out. There were about seven wires that had to be changed. I completely removed the AFM wires and used the MAF wires from the 300ZXT harness because they are longer and I was originally going to relocate the MAF. SleeperZ may remember exactly how many wires had to be changed. All in all, it took me a few hours to unwrap the two harnesses, swap the wires and then rewrap the completed harness. The hardest part for me was finding a 280ZXT harness in a junkyard. Josh Quote Link to comment Share on other sites More sharing options...
JoshB 240Z Posted May 23, 2002 Share Posted May 23, 2002 ooops. You also have to swap the trigger wheel in the distributor to one from a Z31. Another five minute job. Josh Quote Link to comment Share on other sites More sharing options...
Tony240ZT Posted May 23, 2002 Share Posted May 23, 2002 The only difference in the trigger wheel that I can see is that the #1 cylinder has an elongated square. I'm having a hard time finding a Z31T distributor to get the plate from, so I think I'll just mod my plate. My 280ZXT setup is running pretty well on my L24ET, but runs rich when I'm not under boost due to the larger Mustang SVO injectors. I'd still like to try out the swap though. Quote Link to comment Share on other sites More sharing options...
JoshB 240Z Posted May 23, 2002 Share Posted May 23, 2002 Tony, According to JWT the trigger wheels for all Z31 engines are the same. I pulled my trigger wheel from a 300 N/A and do not have any problems. The engine runs smooth and revs to redline. I will keep my eyes open for wheel when I visit the junkyard this weekend. Are you able to find N/A engines? Josh Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted May 23, 2002 Share Posted May 23, 2002 Ron - I am still using the stock 280ZXT fuel system (injectors, pump, regulator). I am running a V trim T3/T4 hybrid, intercooled, at 12 psi with no indications of leaning out. As soon as I can get out to the strip, I will be inching the boost up and find out where the fuel system limit is. I don't intend to just throw fuel at a stock ECU - just adding injectors or changing fuel pressure will screw up the drivability and my fuel mileage and emissions. When I run out of fuel (injector), I will first try adding unmetered air to balance the extra fuel, and fine tune it with the MAS. Ultimately I intend to reverse engineer the ROM code in the ECU and write my own fuel and ignition maps (I'm cheap - why pay JWT $600 for something that is close but not quite right?). Quote Link to comment Share on other sites More sharing options...
Tony240ZT Posted May 23, 2002 Share Posted May 23, 2002 Josh, there are lots of NA's but all of the distributors are gone for some reason. It's like the first thing people yank off of these cars. I guess people think they have failed on their cars, but it's likely something else. If you find one see if you can yank out the plate for me, thanks. I'd love to be able to write my own maps. I don't have experience burning eproms, but am willing to buy into the hardware if it'd be cheaper than having JWT do a job on this thing. I really think that we should study this stuff and come out with the info openly, or at least for a much better price than what JWT is offering. For that price you might as well go with SDS. I'm a computer programmer if you get to a point where you think you could use my help let me know. BTW, I'm running 11psi on the 280ZXT setup with the larger injectors and no intercooler without running lean or detonation on pump gas. I'd love to have an intercooler and pump it up some more. My CR is 7.56:1 with the L24ET, I think the L28ET is 7.4:1 or there abouts. Quote Link to comment Share on other sites More sharing options...
R0N Posted May 23, 2002 Author Share Posted May 23, 2002 Tony & Josh, We notice no difference using the trigger wheel from the 280ZXT from the 300ZXT. Both goes to 7000 no problem. Absolutely no difference noticed. That's why I mentioned no distributor mod. Quote Link to comment Share on other sites More sharing options...
Bernardd Posted May 23, 2002 Share Posted May 23, 2002 Guys, I have the old JWT code they used to convert the 86 300zxt ecu to work with the 280's. I have tried this code several times with no success. JWT does some hardware mods to eliminate the extra 300 sensor's as well as modifying the code. The puzzling thing is the JWT fuel maps are not a whole lot different to the stock maps. The info I have is available to anyone who asks, in the hope that someone is able to find the changes they make or able to modify the stock code to work with larger injectors. I have a feeling it's easier to effect injector sizing with hardware than with the code. I have a Megasquirt system ready to install but I'd rather have the 300zxt ecu running the show. Any software guys that want info just ask and I' ll tell you what I know. Bernardd Quote Link to comment Share on other sites More sharing options...
Tony240ZT Posted May 24, 2002 Share Posted May 24, 2002 But even like 12 pounds of boost is no fun.. I want to be in the high 12's in the 1/4! Un-metered air might be a good way to do it. Do you have a suggestion for making the un metered air be adjustable easily, maybe a small throttle body? Sounds kind of cluttering, but anything to keep from having to empty our pockets for a stand alone Quote Link to comment Share on other sites More sharing options...
JoshB 240Z Posted May 24, 2002 Share Posted May 24, 2002 Ron, I don't doubt it. I have both wheels and could never tell them apart. I only swapped them because it was easy to do and I wanted to be sure that everything was perfect. I was starting a new engine and didn't want the trigger wheel to be a source of unhappiness. Either way, I think the swap is a good one. The MAF is easier to locate and cleaner looking than the AFM. It's also easier to find in local yards. The one downfall I found is that you cannot run bigger injectors as easily. SleeperZ mentioned having to introduce an air leak to compensate for bigger injectors. Unfrotunately, there is no spring to twist making bigger injector swaps easy to tune for. I TRIED to run SVO injectors with less than good results. The brief moment the engine would run would produce a thick layer of smoke and unburnt gas that didn't even rise more than a few feet above the ground. The car would then foul the plugs and die. I went back to the stock injectors and have the boost left at stock. Once I get an intercooler on the car I will begin turning up the boost. Josh Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted May 24, 2002 Share Posted May 24, 2002 Hey Guys, I have the JWT ecu in my 280ZXT, although I am using the cobra maf, which flows more air than the nissan meter, and I have 420cc injectors. Here is what is up with the fuel pump. The 280ZX controls the fuel pump with positive power, the 300 controls it thru the ground. Th black wire on the fuel pump relay under the dash needs to be grounded, and then your fuel pump should be able to be controled by the ecu. I don't think you can just put a JWT chip in it either. I think they make the chip removeable, but I never looked at my ecu, I bought it and had it dropped shipped from the salvage yard to Clark. My set-up uses the 89 ecu, and I have to swap the number two of the injector wires, don't remember which, and disconnect the det. sensor. I did use the chopper wheel from a turbo 300 distr, though. I agree with you that it is light years better than the stock set up. If you wanted to run bigger injectors, why not put some sort of voltage controller in line between the MAF and the ecu and adjust your signal voltage? Seems like that would work to me. Another option would be to do like the do on the 300TT and have two sources of inlet air, and use the "adjuster" to control the bigger injectors, which would also increase you total airflow you could put in the engine. I am worried you may not be able to get the signal adjusted low enough to control the bigger injector is all. The harnesses are all basically the same from what Clark told me. FYI. Oh and I did have to run a ballast resistor on each injector they gave me to raise it to a high impedance to work with the ecu. Would not want to fry the injector driver. If you want a 280zx to get down in the 12's you are going to have to run more boost than 12psi. I got into the 12's on street tires once at about 19 psi with an H trim, which is not much bigger than the V. Now with drag ta's I can rack them off at will. I just put 3.90's in the back, so we will see what that does. So far my fast pass is 12.779 at 113.75.I expect the 3.90's to improve that a few tenths and a couple of mph.When I upgrade the turbo, I am hoping for low 12's or high 11's, and then I am going to find a 240 body to stick all this stuff in and see what shedding 800 or so pounds will do. One other thing you could do is get an adjustable FPR and raise your static fuel pressure, and then adjust your signal voltage to compensate. You would have to have a pretty strong pump, like the peirburg from Cartech, but you need a good pump anyway. I bought an adjustable bosch regulator from JWT and it works just like the stock one, it is just that I can adjust the static pressure. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted May 26, 2002 Share Posted May 26, 2002 Trigger Wheels!! ...I got two extras from 85ZXT VG30DET. Anyone looking for one lemmeno. Cheers! SmackZ Quote Link to comment Share on other sites More sharing options...
R0N Posted May 26, 2002 Author Share Posted May 26, 2002 SmackZ, I'd like one. How much do you want for it? Quote Link to comment Share on other sites More sharing options...
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