Which ignition?

db · Post by db » Thu Jul 07, 16 10:25 am

It looks like I may have to replace my ignition.
There are like ten different MSD boxes ranging from £170 to £500.
Some have obvious differences, some less so.
The Streetfire for £170 seems fine to me. It makes sparks and has a rev-limiter.
Is there any reason to go upmarket?
This for a 99% street driven, occasional rwyb, reasonably hot SB motor?

Blue · Post by **Blue** » Thu Jul 07, 16 11:01 am

6AL2 was always my choice, had a rev limiter and the capability to add almost anything you could ever need. After they cheaped out went bust and came back, they had a high failure rate so I went away from MSD. Now I'm using a billet FBO unit, it has a rev limiter which is all I need.

Pete · Post by **Pete** » Thu Jul 07, 16 11:05 am

As I said in the earlier Post, the only limitation on the Streetfire is you have no ignition retard facility in the event you run nitrous.

All the MSD 6 series at least allow you to plug in a Retard unit (maybe at a later date). I cannot work out how a Nitrous system will work with a 4 speed triggered via WOT - it will be OFF - ON - OFF - ON - OFF, etc up the track and the ignition will be all over the place unless you knock 5 degrees out of the timing by moving the Dizzy - then it will not be at optimum when you are not using Nitrous.

I run a Streetfire on the Super Bee and it is great and very compact - mind you, I do carry a spare with the car.....

GJUK · Post by **GJUK** » Thu Jul 07, 16 3:21 pm

6AL2 on my car, total transformation.

Easy to wire, 2 limiters (one for total rev limit and the other for burning out your gearbox internals). Bought it direct from Summit, worked out much cheaper thanks buying from a UK supplier.

db · Post by db » Fri Jul 08, 16 10:09 am

[quote="Pete"]As I said in the earlier Post, the only limitation on the Streetfire is you have no ignition retard facility in the event you run nitrous.

I just read the instructions for my Mallory retard and it claims to work with "Mallory Hyfire or ANY COMPARABLE TYPES OF CDI CONTROL with an ELECTRINIC IGNITION AMPLIFIER TRIGGER". So it should work with the MSD Streefire

All the MSD 6 series at least allow you to plug in a Retard unit (maybe at a later date). I cannot work out how a Nitrous system will work with a 4 speed triggered via WOT - it will be OFF - ON - OFF - ON - OFF, etc up the track and the ignition will be all over the place unless you knock 5 degrees out of the timing by moving the Dizzy - then it will not be at optimum when you are not using Nitrous.

The timing must shift in milliseconds, yes it'll change with each on-off of the throttle but does that matter as long as it's correct at each moment?
The nitrous has to be on a wot switch as the motor would go bang if the throttle's lifted with the nitrous still on.
I don't like the idea of pre-retarding the ignition with the dissy for the reason you mention.
The only other option is full throttle shifts... I don't think either me or the drivetrain are quite up for that, yet

db · Post by db » Sat Jul 09, 16 11:00 am

Using tips from Pete and others (thanks!) I'm confident my ignition box has packed in.
I've plumped for a Streetfire unit. It's half the price of the 6al, it has a rev limiter, I can use my Mallory retard (works with any ignition) it provides multiple sparks at low rpm and 43kv at high rpm. Also it's small, neat and simple to wire up.
All boxes ticked

Pete · Post by **Pete** » Sat Jul 09, 16 11:02 am

Are you sure the Retard unit did not kill the spark box?

That will play on your mind

db · Post by db » Sat Jul 09, 16 1:24 pm

Thanks for that... Yes it has occurred to me