ykp53

the title says it all?

tshort

I'm sure there are more but having a rev limiter is nice insurance.

77-C3 & 89-C4

If compared to the GM HEI very little Just a huge price for the MSD unit taht will mean zero performance wise.

Fevre

I agree on a stock set up but when running a bigger cam it helps smooth out the idle, better/quicker starts and better low rpm throttle responce. Plus the stickers look :cool: on your work bench. :)

zwede

Capacitive Discharge systems (such as MSD) are useful in the following cases:

Super/turbo charged
High compression (>12:1)
High rpm over 6500.
Nitrous

All of the above create high cylinder pressures (except high rpm) which makes it hard for an inductive discharge system to jump the plug gap. High rpm is hard on an ID setup as the coil has very little time to recharge.

CD systems are very good at firing a rich mixture. They are very poor at firing a lean mixture, though. That's the reason for the multi-spark. They count on atleast one of the sparks to ignite the mixture. However, if the 2nd or 3rd spark ignites the mixture, the timing will be retarded for the cycle.

A CD spark is short and strong, vs the ID system spark which is weaker but much longer.

norvalwilhelm

I like my MSD so much I bought 4 of them. A msd-6al for the ignition and rev limiter, the MSD timming master to give me a consistent advance curve, a msd timming controller to fine tune the car when running down the road for maximum timming and finally the msd boost/retart system for controlling the timming under boost conditions.
All the components seems to give me years of maintenace free running with my plugs staying clean under all conditions.
I like msd and if you know how to trouble shoot them they are very easy if you ever would encounter a problem.

8T1-7T9 BIONIC VETTE

Since you have the knowledge of this system.....I'm in the middle of engine tear down....while I'm at it....I installed the MSD6AL box....I installed it inside my glove compartment. Do you see a problem with the install location of the box??? I was told there could be a heat issue with the box enclosed like that...What do you think?

WashingtonRacer

is HEI Inductive? I am confused here!!. for some reason I thought that MSD was inductive, and also CD.

zwede

HEI is inductive, MSD capacitive (exept the MSD5A which is inductive).

WashingtonRacer

that is odd, i just bought a f.A.S.T. system. it's for GM HEI, but they have an option to upgrade to Inductive pickup. and state you need to do this if you want to use MSD. I was really confused about this, and still am.

zwede

The inductive pickup they talk about is the sensor that generates a signal to the ECU telling it when to fire. The pickup has nothing to do with actually firing the coil, it just generates a signal. The ECU then figures out the exact time the coil should fire (based on the pulse it received from the pickup and then offsetted to achieve the correct timing advance). The ECU sends a signal to the MSD box telling it to fire the coil. The MSD box is capacitive discharge.

To fire a coil you send current though it and then cut the juice. The collapse of the electromagnetic field in the coil generates a secondary high voltage spike which fires the coil.

In ID you use the battery to send juice to the coil and in CD you use a capacitor as an intermediate step to store it. The CD capacitor has a lower internal resistence than the battery which means the coil can be charged faster and to a higher degree.

zwede

BTW, I'm surprised FAST requires you to switch to an inductive pickup just to use a MSD box. I'm running an accell 300 and also tried an MSD6A with a holley commander 950 and either one ran fine with a 8-pin small-cap HEI and ECU controlled timing advance.