280ZXT Distributor with Progammable MSD

[z-ya]

I've been experimenting with different distributors to trigger an MSD 6AL2 programmable (6530):

 

 

The nice thing about this unit is that you can control the timing curve when you lock the advance mechanism in your distributor. It also has boost retard and a rev limiter. Since I'm using it for an NA road race application, it's got everything I need. So for about $150 more than a standard MSD 6AL, I get complete control over the timing curve.

 

So which distributor to use? I first took apart a 280Z distributor and welded both the mechanical and vacuum advance mechanisms. It triggered the MSD fine using the magnetic pickup input wires.

 

Realizing I have a 280ZXT distributor, I figured why not use that? Might be a bit more precise than the mag pickup. Also, since it puts out a +12v signal, it should be effected less by electrical noise than a low voltage signal from a magnetic pickup. Below is how you connect the 82-83 280ZXT distributor to an MSD 6AL2. Pretty easy, and it works great. Remember to shield the +12v and signal wires from the distributor to the MSD.

 

 

Here are the settings (in red) that you need to change to use the 280ZT distributor with the 6AL2:

 

 

Her is a simple curve I used to test:

 

 

It is what they call a "run retard" curve. So you need to time the distributor to the max advance you think you might need. I would suggest 38-40 deg BTC. Then you can retard the timing at whatever RPM point you want. The MSD interpolates between points to smooth the timing curve BTW.

 

I plan on using this setup on my road race build. stay tuned as I will post dyno results in the spring.

[KillerBjt]

Very interesting, how accurate would the reading the distributor be since there is a lot of play in the mechanism? I remember TonyD or Johnc talking about that in another thread.

[z-ya]

The point isn't that this approach is better than a crank trigger. But it is better than using a welded distributor with a magnetic pickup.

[KillerBjt]

I figured that, i guess i was just trying to get a idea of how close this would be as this seems a viable option for me.

[NewZed]

You could put a six tooth reluctor ring on your damper and get the stability of a crank trigger.

[z-ya]

You could put a six tooth reluctor ring on your damper and get the stability of a crank trigger.

 

Ummm, duh (sorry). A crank trigger is against the rules in the class I plan on racing the car in. I have a compete crank trigger setup, and I would love to use it!

[NewZed]

My comment was mainly for KillerBjt. He asked the question.

[NewZed]

I was kind of off-base on this anyway. The crank spins twice as fast as the distributor so you'd end up with wasted spark on a single coil. That might be too much for the coil. Unless you used a three tooth wheel on the crank.

 

My mistake. I'll go back to my own business now...

[NewZed]

I was kind of off-base on this anyway. The crank spins twice as fast as the distributor so you'd end up with wasted spark on a single coil. That might be too much for the coil. Unless you used a three tooth wheel on the crank.

 

My mistake. I'll go back to my own business now...

 

A three tooth wheel would not work. I just figured out that I don't know what I'm talking about. Just correcting an error...

[JSM]

Subscribed: Also, is there any bennifit to updating to the 300zx choper wheel and CAS? Just curious.

[z-ya]

Subscribed: Also, is there any bennifit to updating to the 300zx choper wheel and CAS? Just curious.

 

I'm not familiar with that mod. So far this setup has worked fine on the dyno and limited track time.

[HowlerMonkey]

Would a factory crank trigger setup be illegal?

[FricFrac]

Doesn't the '81 turbo CAS put out the same signal as the 82-83 optical encoder in the Dizzy? They have the same plug connector for the '81 turbo CAS and the 82-83 turbo Dizzy. As far as I know the '81-83 turbo ECUs are interchangeable (other than the '81 requires ballast resistors for the low impedance injectors and the '82-83 ECU has them built in). The 82-83 Dizzy is essentially an optical CAS whereas the '81 uses a reluctor CAS.

 

It would be interesting to see how this works with a turbo setup as the turbo ECU controls timing normally. The boost retard is a nice feature as well. The issue would be with the knock sensor. If the ECU no longer controls timing it can't retard the timing if knocking is occuring. From what I could see in the 6AL2 user manual there is no input for a knock sensor.

 

 

[z-ya]

Would a factory crank trigger setup be illegal?

 

If it is a vintage racer, and it was raced back in the day with the crank trigger, it would be legal. I don't know of any pre 72' vehicles that came from the factory with a crank trigger. Since my car was never raced back in the day, I need to conform to the rules for the class, which requires a distributor trigger.

[z-ya]

Doesn't the '81 turbo CAS put out the same signal as the 82-83 optical encoder in the Dizzy? They have the same plug connector for the '81 turbo CAS and the 82-83 turbo Dizzy. As far as I know the '81-83 turbo ECUs are interchangeable (other than the '81 requires ballast resistors for the low impedance injectors and the '82-83 ECU has them built in). The 82-83 Dizzy is essentially an optical CAS whereas the '81 uses a reluctor CAS.

 

It would be interesting to see how this works with a turbo setup as the turbo ECU controls timing normally. The boost retard is a nice feature as well. The issue would be with the knock sensor. If the ECU no longer controls timing it can't retard the timing if knocking is occuring. From what I could see in the 6AL2 user manual there is no input for a knock sensor.

 

I should work.

 

I use the timing retard curve, which lets me control the timing vs RPM. I pull back I think 25 degrees below 1000RPM for starting. Makes a 13:1 motor much easier on the starter

[FricFrac]

I should work.

 

I use the timing retard curve, which lets me control the timing vs RPM. I pull back I think 25 degrees below 1000RPM for starting. Makes a 13:1 motor much easier on the starter

 

Yes it should work. I was just saying that you would loose the timing retard if there is any knocking for the turbo ECU application.... Great idea btw using the '82-83 turbo dizzy. It should be more accurate than the reluctor dizzy and welding/bolting/otherwise disabling the reluctor setup on the NA dizzy.

 

The '81 turbo was the first Z to have a CAS and the '82-83 is a CAS as well - it's just hidden in the dizzy (and optical vs reluctor) so I suspect if you wanted to get technical the '82-83 turbo dizzy probably isn't leagle either....

[z-ya]

Yes it should work. I was just saying that you would loose the timing retard if there is any knocking for the turbo ECU application.... Great idea btw using the '82-83 turbo dizzy. It should be more accurate than the reluctor dizzy and welding/bolting/otherwise disabling the reluctor setup on the NA dizzy.

 

The '81 turbo was the first Z to have a CAS and the '82-83 is a CAS as well - it's just hidden in the dizzy (and optical vs reluctor) so I suspect if you wanted to get technical the '82-83 turbo dizzy probably isn't leagle either....

 

It just can't be triggered from the crank, and specifically say distributor. It doesn't say which distributor...

[FricFrac]

Lol - so just adding a shaft from the crank to the distributor makes it legal - that works Lucky Nissan changed the system after only one year on the '81 to the Dizzy version for '82-'83!

[Logoleaf]

Hi guys,

Im in the middle of setting up E12-80 dizzy with MSD 6A. After gone through this post, im confuse with deciding which dizzy to use. I have both dizzy, turbo and e12-80.

I will be using z31 ECU with 280zx wiring harness. Im going with JimWolf setup.

 

Can you guys give me a good idea of using the 280z turbo dizzy?

I have already installed the e12-80 to the MSD but still not sure if i would need to make any connections to the ECU? Please help to walk me through this since i have never done this. Thanks and appreciated!