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L28ET Needs MSnS or just MS?


datzun240

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Im looking into getting MS, but was wondering if my 81 280zx motor needed MSnS or if i could just start with fuel control using MS and then when i needed the extra spark control move over to MSnS. Im just not 100% sure if my 81 ECU is needed to control the spark or not. I was looking through the diagram and see the YW that sends negative pulse, but can someone clear up my assumptions and ideas to real facts? Hope to hear from you guys.

 

regards-

 

david

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Guest Loose_Screws

I am not sure of the wiring on the '81, but will definitely suggest going with just MS first. MSnS is a whole different animal and there are MANY parameters and settings to learn/tune at once.

 

I progressed from MS to MSnS to MSnS 'extra'. And I am now starting to use some of the additional features of the 'extra' code, such as boost control. By starting with MS, it was easier to eliminate causes of problems when they occurred. With MSnS, it gets more complicated. People have started with MSnS, it can be done, but prepare for a few long nights in the garage!

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Yea. I was just trying to determine the facts from my assumptions. I spoke w/ Tony D a little bit about the swap with the 81 CAS, he's out of the states right now, but i hope to speak w/ him when he comes back. He told me a bit about Moby's maps, but im wondering if i can just run MS w/o the MSnS in the beginning. Thats wut i would ideally like to do, but if hooking up MSnS isn't much of a big step above MS (as far as wiring goes) then i'd take it on. I couldn't imagine it being much more difficult than trying to wire up the L28et into the 72 chassis, but i'd like someone else's opinion. I hope to get a clean cut answer about the Ms or MSnS before i begin to start making plans. thanks for the replies hope to get a few more.

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Guest Loose_Screws

If your car is not a daily driver and you have the patience, go for MSnS. You will receive plenty of help from this board and msefi.com.

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Ok... yea my 240Z isn't a daily driver. I drive it anywhere from 1-3 days a week and only for short periods of time (15-30 mins). It doesn't leave far from home and i do have time to learn the tuning part of it, but i figure i'll get myself familiar w/ MS or MSnS before i buy the standalone. I've heard many people say start with MS first and then upgrade to MSnS b/c you mite run into problems and if u try to do too much @ once then it may turn into a headache. I WANT to just go w/ MS, but if i need ignition control too then i gotta do wut i gotta do. thanks for the quick reply.

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You do not need MSnS, you can actually let the ignition side be taken care of by an MSD box that provides timing retard with boost.

 

I think this is how they did it before spark control. If you just run MS by itself with no spark control, it would be using the mechanical and vacuum advance of the distributor. Problem is I don't think the turbo distributor really has much advance, or any.

 

Mario

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There is NO turbo distributor!

 

On a US specification ZXT, the easiest method is to simply go with MSS from the start!

 

Of course, if you want to source a European or JDM distributor for the turbo L-6, THEN you could use it as MS alone, with the vacuum/boost cannister taking care of retard in the stock zone.

 

Of course when you later converted to MSS, you would end up going to a fixed trigger, and negating that neato Euro Dizzy to begin with.

 

The 81-83 Turbo Distributor is just that, it distributes the spark (on an 81 that's ALL it does! There ain't but a rotor in there!). It has absolutely nothing to do with spark production in relation to engine speed like a conventional distributor.

 

It is a dumb box, it does nothing but shoot the sparks. It doesn't advance, it doesn't retard, and without an interface to read the pulses from an 82/83 CAS housed inside there, it won't even give you a timing pulse!

 

Now, for a conversion of an 81 to MS alone, you most likely would simply install a convetional ZX Distributor, along with it's support, into the place where the 81 Dizzy went. It is the ONLY turbo engine in the US that will do that easily. (The 82/83 have a different spline configuration and will need to have the oil pump dropped, and the dizzy shaft rephased and reinstalled with one compatible with a distributor.) After you have a conventional distributor in there, you can use an MSD box, have it fire the coil and do whatever you like with the spark as far as retard. Advance you are limited by centrifugal in the mechanisim, along with vacuum advance canister limitations, of course.

 

For all the hassle, simply use the tables Moby has for the spark. I have mine working again. I made a miscalculation on the number of degrees I was advanced, and had entered the wrong numbers. Under high vacuum conditions the spark was "jumping" one terminal in the firing order (at least that is what I think was happening) I have now made successful pulls in fourth up to 4500rpms (3.36 rear end) with no surging, no popping, no spark knock, nothing.

 

Though now upon having my 81 CAS unit off the car and looking closely again, I may be able to do another mod that will not entail removal of the front pulley and rotating it for maximum advance. I had misinterpreted the timing information given in the FSM, and with a bit of work with adremel tool it MAY be possible to get just enough advance for the 81 CAS to work without pulling the pulley off, and drilling the second hole.

 

Just for information, I will probably use my spare 81 CAS for a N/A conversion to MSS, and my spare 83 CAS/Driveshaft combo for another conversion of an N/A engine. The real advantage of standalone is being able to tailor your spark curve. Mobys timing is safe and works, you can always tune it later on. But there is really only so much you can do with fuel alone. And spark advance available in Moby's tables should add up to far better cruise and partial throttle economy than the stock system had!

 

Can you tell I'm in a hotel room now with time on my hands? LOL

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TONY D... remember me? hahaha! Well yea im still looking into and i found that the best thing to do is to go straight to MSnS as soon as i figure out all the wiring necessary. I also messaged MOBY and he suggested to just convert over to the 82/83 dizzy w/ internal CAS. As soon as i find one online or for a good price, im going to get it b/c the parts store wants an arm, leg and my first born child just for one. So im going to go ahead and do that, not that im giving up on the 81 CAS, but i think its a little out of my league if u kno wut i mean. Well i hope to have a chat w/ you when u get back in the states. Thanks for the input and all the extra info. Have a good one.

 

regards-

 

david

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what's and arm, leg and firstborn child going for in NorCal these days?

 

Here in SoCal Autozone asks around $240 for a reconditioned CAS for an 83, and the dizzy shaft may still be available from Nissan for all that's worth!

 

I would bet the conversion can be done using "new and warranted parts" for under $300!

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