MSD ignition

[freakyjason]

hey guys!

i was thinking about getting a msd 6a ignition control unit for my '92 240sx.my car is basically stock so i dont have after market distributer, coil, plugs or plug wires and stuff like that. i heard that since my engine is basically stock, if i install the msd control unit i might run the risk of scorching my pistons or plug wires. is this a valid concern?

thanks!

[freakyjason]

another question. are these units model or brand specific or can i buy any unit made for a four cylinder engine? also, what is this 8910/8911 tach adapter everyone is talking about? do i need one?


Modified by freakyjason at 1:58 PM 2/18/2006

[sunnys14]

alot of people run msd ignitions and dont have a problem with the tach. the only ones that seem to have that problem is SOHC ka's

[freakyjason]

thanks man! good to know. but i still dont know if they are model specific or if they will do any damage to my stock engine components.

[JNM240]

No and No. Get any one designed to be used with a 4 cylinder engine. I have the MSD-6AL with rev limiter, and it works for 4, 6 & 8 cylinder engines. The tach adapter is a must for the SOHC motor, since the tach signal uses only 6v, where the DOHC uses 12v. DOHC obviously doesnt need it.

[freakyjason]

okay , that answers that but do i need to modify any of my other ignition components for my car to be able to accept the msd? will it do any damage to my stock wires, plugs and pistons?

[JNM240]

No it wont damage anything stock. You will need to cut wires to install it, and i havent istalled one in about 8 years (on my car) so i couldnt off the top of my head tell you how or what wire goes where. I use the Blaster Coil as well and run stock wires and NGK plugs, no problems.

[freakyjason]

thanks a lot! thats all i needed to know!!!

[s13satch]

If you are looking to purchass the MSD to gain power, don't waste your money. As I've stated on here before, I installed the 6A on my '91 na ka for my senior thesis in college and made next to no power on the dyno. I did a 4th gear pull from 40 to 100 mph and gained an average of .6 hp and 1.6 lb/ft. I also did pulls without opening the gap on my spark plugs and I lost an average of 1.9 hp and 3.2 lb/ft.

[freakyjason]

yeah, thats what ive heard. the real reason why im doing it is to improve efficiency. my car is running a little rich (which is a completly differnt story) and i figured this would save me a little at the pumps. also, its just one more thing to say ive done to my car.

[s13satch]

also, its just one more thing to say ive done to my car.

That’s the reason I bought it. I already had all the other bolt-ons for the KA except an electric fan. The MSD was the easiest of the two to dyno back to back. While I haven't really noticed a difference with the fuel mileage, I can say that the car idles extremely smooth. It will be interesting to see if the MSD helps you with fuel mileage in a rich condition since the origins of MSD comes from igniting lean mixtures.

[freakyjason]

It will be interesting to see if the MSD helps you with fuel mileage in a rich condition since the origins of MSD comes from igniting lean mixtures.

yes it will. ive done a bit of research and read a lot of reviews. it seems to make more of a difference on higher displacement engines. i really dont know what its going to do with my application. ill keep you posted. it should be here on friday.

[geebzter808]

i noticed that my car sucks more gas. the rpm is alot more smoother at higher rpm. i sugest you to not buy it.

[JNM240]

Ive been running a MSD-6AL for 8 years now and have no problems whatsoever. As a first mod, i might not suggest, but i got mine to solve the same problem he is having: car running a little rich. Eight years later, and a whole lot of NA mods later, i have absolutely nothing to regret. Get it if you want it.

[InsanityInc]

the only purpose of aftermarket ignition systems is to ignite the spark if your stock system cannot handle the VE of your engine. You have to go WELL over stock VE to ever experience that. Otherwise an MSD coil will do absolutely nothing.

[Chezedik]

You may want to think about running a ground to your MAF, it often helps overly rich conditions.

[s13satch]

As a little side note, I just had my car hooked up to an oscilloscope today. I must say that the firing lines are interesting to say the least.

First, MSD advertises about 6 firing at idle and a switch over to single capacitive spark around 3000rpm. I figured that these numbers would be higher for a 4 cyl, but I did not expect the numbers I got. At idle (750 rpm) there were 8 firing lines, at 1500 rpm there were 5 firing lines, at 3000 rpm there were 4 firing lines, and at 5600 rpm the MSD was still producing 3 firing lines.

Second, MSD claims that the multi spark or single capacitive spark will last for about 20 degrees of crank rotation. At idle the spark lasted about 18 degrees. However, as the rpm increased the firing time also increased. At 3000 rpm the period was around 30 degrees and at 5600 rpm it was around 40 degrees. Last, my firing lines where only 3,000 to 4,000 volts! For those of you who understand electricity principles and ignition system operation you will understand why this is so odd, especially since is running a .050” gap.

[JNM240]

Last, my firing lines where only 3,000 to 4,000 volts! For those of you who understand electricity principles and ignition system operation you will understand why this is so odd, especially since is running a .050” gap.

Its just this last part that i dont understand. Please explain for us.

[s13satch]

Its just this last part that i dont understand. Please explain for us.

The short answer:The initial firing line (the amount of energy needed to jump the spark plug gap) should be around 20,000 volts for our car. When the plug gap is increased on any car, more energy is needed to jump the gap. This is why MSD recommends cars with older style ignitions to use their ignition coil which is capable of 45,000 volts. This is also similar to the theory behind "performance" plugs. With a smaller center electrode, more voltage is needed to jump the gap, thus creating a slightly “hotter” spark. It doesn't follow logic that I am only using 3 - 4 kV. I am running both a larger gap than factory, and the plugs with the smallest center electrode (NGK Iridium IX). My initial reaction was that there was a problem with the scope. But we used it on a Jeep right before my car and the machine worked fine. I will have to do some more thinking to come up with an answer.

[freakyjason]

does this create any problems that youve noticed?

[freakyjason]

You may want to think about running a ground to your MAF, it often helps overly rich conditions.

how do i go about doing that? just solder a wire from the maf to the chassie?