I have a holley 390 cfm 4v, and need msd to burn all the fuel. I need to know what model to get? And ask the experts!
Do i need 6AL, 6A ?!?! I don't know. I also have pertronix electronic ignition. Will that effect anything?
I used the 6AL on my set up as it has the RPM rev limiter.
Can't remember the difference between the A and the AL but I think that is it.
The A model does not have the limiter, but the AL does. I think that the basic unit operates the same regardless.
The AL unit has the option of a plug in module, ( a separate piece ), that will disrupt ignition sequence gradually at a specific rpm range. There are various rpm ranges available, (units), that will plug in, (two prongs protruding from about a half inch square gizzie), so that the engine will not rev above the desired rpm limit.
This I suppose so that an inappropriate amount of fuel is not dumped into the chambers with the chance of a backfire or other problems that arise during sudden deceleration.
The end result is the same, however in the Pinto four cylinder engines, (2000 and the 2300), my concerns are in the top end of the engine and the belt that drives them. The bottom parts are pretty strong.
Also as I remember with all units, there is a button that you must adjust with a pair of mini cutters to prepare the unit for four cylinder ignition. I believe they come from the factory set for eight cylinders. All units that I am aware of are compatible for four, six, or eight cylinders.
My guess is that it depends how much you wish to modify as to which unit you prefer. If you do not wish to go all out hog wild, I think that the A model will work just fine. Am not aware of the price difference between them.
Al
Does the msd give full multiple sparks at all rpm's? My problem is in the higher rpm range. I have a four barrel, and need to burn all the gas when i open the secondaries!!
Well i have very little information.
I like the crane because of the internal construction,( surface mount military style and neat wire routing.That spells reliabilty to me. Also the built in rev-limiter (no pills needed for a change in limit) adjustable in 100 rpm inc.
Appantly None of the popular boxes will give you multiple sparks above 3000 rpms. Everythings happening "too fast".
The pertronix "second strike" has 2 after 3000 rpms. I know nothing of this unit allthough it sounds good.
http://www.pertronix.com/ignition_products/second_strike.htm
The crane advertises max multiples of 12 up to 3000. But it tapers off the closer you get to 3000.
The pertronix setup isnt listed in the Crane instructions, But it is in the MSD
Good luck!
The MSD6AL and Crane Hi6 both look very similar in function.
Crane Hi6 http://www.cranecams.com/?show=browseParts&lvl=5&prt=130&action=partSpec&partNumber=6000-6400
Primary Voltage Output 450 volts
Primary Energy Output 1200 millijoules/sequence
Dimensions 8?L x 4-1/2?W x 2?H, 4-1/2 lbs
Operating Voltage 6 to 18 volts, reverse polarity protected, negative ground only
Current Draw 7.0 amps max at 10,000 RPM
Peak Spark Gap Current 380 milliamps with LX91 coil, 510 milliamps with LX92 coil
RPM Limiter Accuracy ?30 RPM
RPM Limiter Range 600 to 9,900 RPM in 100 RPM increments
Timing Accuracy ?0.5 degrees from 500 to 9,900 RPM
Multiple Spark Duration 20? crankshaft rotation below 3,000 RPM. Maximum 12 sparks per seq. with 1 millisecond interval between sparks.
Description
Multi-Spark CD, for race, street, up to 14.5:1 compression ratio, nitrous-oxide, supercharged and turbo. More HP, torque, crisper throttle response! For 4, 6, 8 cylinder with distributor.
MSD http://www.msdignition.com/ignition_6_6420.htm
Operating Voltage: +10-18 VDC Negative Ground
Current Requirements: 5 Amps-5,000 RPM
10 Amps-10,000 RPM
RPM Range: 15,000 RPM with 14.4 Volts
Spark Duration: 20° Crankshaft Rotation
Energy Output Max: 105-115 mJ Per Spark
Weight and Size: 3 lbs, 8"Lx4"Wx2.25"H
Voltage Output Max: Primary: 460-480 Volts
Secondary: 45,000 Volts (Blaster Coil)
thanks alot!!
NP. let us know what you choose..
The pertonix box is pricey though.. over 280