Which MS should i use for my A18A?

[junhung]

newbie here.. i'm Lawrence from Malaysia.. there not much ppl using MS in m'sia.. so i couldn't get much info from locals..

currently driving 2nd gen 1983' Honda Prelude with stock A18A/ET1 Sohc twin carb engine..
i planned to convert to efi and turbocharge it with 4AG quad throttle & small TD04 turbo..
there is no camshaft or crankshaft position sensor on this engine..
so which ms ecu suitable for this set-up?
*engine uses the old type distributor, i don really know what type is that >.<

[Matt Cramer]

I think you'll like some of the MS2's ability to blend TPS-based and MAP-based fueling for running four throttle bodies on a turbo motor, so you'll definitely want a MS2 V3.0 (if building from a kit) or MS2 V3.57 (if buying ready made). Biggest question is what to do with ignition. It may be easiest to lock out your distributor or put on a later distributor, or you could do something like an EDIS conversion.

[cygnus x-1]

newbie here.. i'm Lawrence from Malaysia.. there not much ppl using MS in m'sia.. so i couldn't get much info from locals..

currently driving 2nd gen 1983' Honda Prelude with stock A18A/ET1 Sohc twin carb engine..
i planned to convert to efi and turbocharge it with 4AG quad throttle & small TD04 turbo..
there is no camshaft or crankshaft position sensor on this engine..
so which ms ecu suitable for this set-up?
*engine uses the old type distributor, i don really know what type is that >.<

Hi Lawrence! I think I can help with this. I converted my 1987 Prelude (A18A1) to MS a few years ago, and have also done a fair bit of modification to the engine. As far as the engine and the rest of the car goes, you should go over to Preludepower.com and check out the 2nd generation forum there. Lots of helpful people and information there.

About the MS:
It's a really good conversion for this car because by now most of the factory carbs are in bad need of a rebuild and parts are getting harder to find all the time. The distributors are completely mechanical, meaning they have vacuum and centrifugal advance. The bearings in these things tend to wear out over time and the vacuum diaphragms leak, so the ignition timing gets sloppy. When I did my conversion I considered locking the distributor, but decided to just do an EDIS conversion instead. It's more work up front but it's far superior to the factory distributor. EDIS is fully electronic (no mechanical parts to wear) and more accurate since it uses a crank sensor for reference instead of the cam. And since you're going to be adding a turbo you would really benefit from a more accurate ignition system.

The only catch to doing an EDIS conversion is that you have to add a crank sensor and trigger ring to the crank pulley. The issue is that there is almost no room to fit these unless you remove the air conditioning system. The crank sensor bracket mounts to the engine block where the AC compressor bracket would normally go and the trigger ring mounts to the crank pulley where the AC belt grooves are. I spent quite a lot of time trying to figure out other ways to do it and nothing was really practical. If you are interested in doing an EDIS conversion and aren't able to source the required parts there, I can also help with that. I've made up a few sets of parts for other people that wanted to do the conversion but didn't have the means to add the trigger ring to the crank pulley.

Since we're on the subject, here are a couple pictures of the crank pulley and sensor brackets I've made. For some reason I don't seem to have any pictures of these on the engine but I could get some if you want.






On the turbo setup, if you're planning to do a full engine rebuild anyway you *might* consider doing an engine swap instead. It will depend on what parts you have available locally but if you can find an A20A engine from a 1985-1987 Prelude or a 1986-1989 Accord, you have many more options for the intake manifold. The manifold on the A18A/ET is unique (there is only one other compatible intake known and it's rare) and not particularly well suited for boost. An A20A engine however can fit some of the more common B18 manifolds with some minor modification. This gets you a single throttle body manifold that's already setup for injectors and fuel rail. The A20A block is externally identical to the A18A so you can use your stock engine mounts. Your stock transmission should also bolt right up as well. There is more information you should know about the swap but it's sort of off topic for this forum. So if you want to know more it would be better to head over to Preludepower.com.

Oh, and to answer the original question, I used an MS2 with the V3.0 PCB. You could use an MS1 as well but considering that the MS3 was just released I think it would be kind of silly to buy an MS1 at this point.


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[junhung]

matt & cygnus.. thanks for your info.. aprreciate it very much

i think i will just lock the distributor.. in tight budget >.< then which one should i choose if i wanna run the fueling only..? mS2? version 3..? i will solder it myself..

[cygnus x-1]

matt & cygnus.. thanks for your info.. aprreciate it very much

i think i will just lock the distributor.. in tight budget >.< then which one should i choose if i wanna run the fueling only..? mS2? version 3..? i will solder it myself..

I think you would only lock the distributor if you want to control timing from the Megasquirt. If you want to control fuel only I would say leave the distributor alone. You may have to turn it back to retard the overall timing to make it boost safe, and possibly put a check valve inline with the vacuum advance diaphragm to protect it during boost, but you shouldn't need to do anything beyond that.

Both MS2 and MS3 would work just fine for fuel only control.


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[junhung]

how much will it cost + delivery to Malaysia..? *MS2 V3.0