M S D 6

[mstrdinan]

 We suspect a problem with the msd
  cant  rev over 65 - 7000  on the salt
   hits 8000 on chassis dyno
   put in 8000 then 8300 chip
  does it make sense to send it back to msd ?
   fuel etc all seems ok                  any Ideas?

   
    305 chev   msd 6al    blaster trigger    wires   
     holley 750
     in a roadster                         thanks     

[racergeo]

  I had the same trouble with my MSD. It would only rev to 7650 on the salt but to 8500 on dyno. Luckily 7650 is 274mph and that is my record in C/GL. LOL

[55chevr]

I have nothing but good experience dealing with MSD repair tech ... great service ... most often no charge ... I sent a distributor that was in an engine fire for repair and it looks like all I got back from the original was the housings as the rest was melted. Charged me less then a new rotor and cap which they included.

[racergeo]

  Like I said the aero of your roadster, your gear ratio and the power of your engine (or lack of) in conjunction with the great white dyno,is acting like a built in rev limiter. We've all experienced it!!!

[nrhs sales]

Change your gear ratio to a shorter gear and see what happens. I se it all the time that folks think just because it will pull 8,000 rpms on a chassis dyno they think it will do it on the salt. They forget that on the salt you have to push a whole lotta air that you don't find on a chassis dyno!!!

I bet your MSD ignition is fine!!

But if you are not sure answer this... Will it pull 8,000 rpms in first gear? if so then you are geared too tall.

[thundersalt]

  Like I said the aero of your roadster, your gear ratio and the power of your engine (or lack of) in conjunction with the great white dyno,is acting like a built in rev limiter. We've all experienced it!!!

That's why I now have a dent in the firewall under my gas pedal

[mstrdinan]

Change your gear ratio to a shorter gear and see what happens. I se it all the time that folks think just because it will pull 8,000 rpms on a chassis dyno they think it will do it on the salt. They forget that on the salt you have to push a whole lotta air that you don't find on a chassis dyno!!!

I bet your MSD ignition is fine!!

But if you are not sure answer this... Will it pull 8,000 rpms in first gear? if so then you are geared too tall.

sorry,    neglected to give all the info...
2 speed powerglide.....and.......
alternator not charging
we
were running on 12 volts     poss prob

[RICK]

I started reading the first post and working my way down,  the first thing that popped in to my head was "Good strong power". Those things suck up a lot of juice, especially at higher rpm's. Like anything, the harder you make it work, the more power it needs.
   Also don't over look the need for a GOOD ground. Bad grounds can run you around the block. Because we drive in a salty/corrossive atmosphere it makes things rust in between the connections.

        Good luck,   RICK

[racergeo]

   I think its your gear ratio. I have a power glide in the Saltosaurus and I can tell you from personal experience that a 2 speed compounds the problem of trying to pull to much gear. First it hurts your run up speed (acceleration) and when you make your gear change your going fast enough that your already coming up against the air wall . The little 305 in. engine is making so little power after the shift that it won't recover as the air resistance mounts. A roadster is probably the worst offender in this regard. I just bought a Liberty 4 speed and expect to see some good gains as a result of a much improved 1/4 mile time. Either way, 2 speed 4 speed or direct drive your final gear ratio must reflect what your car is capable of running (from an aero and power stand point) not what YOU want it to go.

[BALS aSALT]

Change your gear ratio to a shorter gear and see what happens. I se it all the time that folks think just because it will pull 8,000 rpms on a chassis dyno they think it will do it on the salt. They forget that on the salt you have to push a whole lotta air that you don't find on a chassis dyno!!!

I bet your MSD ignition is fine!!

But if you are not sure answer this... Will it pull 8,000 rpms in first gear? if so then you are geared too tall.

sorry,    neglected to give all the info...
2 speed powerglide.....and.......
alternator not charging
we
were running on 12 volts     poss prob

i know running my msd at the drags that if you don't have more than 12 volts , an msd box works like crap. they seem to like 14-16 volts.

[Jonny Hotnuts]

Keep volts to MSD high.
Keep the MSD cool.
Mount the MSD so it is isolated from vibrations.
Go overkill on the grounds.

~JH

[Rex Schimmer]

JHN said it , keep voltage up, make sure grounds a perfect or better.

Rex

[Steve Walters]

OMG;

I think you guys solved my problems.  Does the tach output get fuzzy with this low voltage problem?  I'm Running two optima's with one dedicated to the MSD 6, no alternator, at 5600 the last two years in a row, i've hammered my valves.  My machinist says i'm floating the valves, I tell him that I haven't been able to get to the RPM to float the valves.  The gear thing is also a problem of mine.

Thanks Steve,

[Kato Engineering]

maybe you better hook up two #27 size batteries together to just run the MSD...
you best have a battery volt meter wired in directly...
and another seperate battery system just for powering anything else.

have a 5000watt generator powering up a giant charger
hooked up to a seperate extra pair of batteries in the pits..change out the batteries for the fresh ones every pass.

the high heat and salt conditions really take a toll on batteries...

[Steve Walters]

I have an inverter on the truck that charges the optima's in between runs.  Ten minutes to fully charge the pump battery, 7 minute to fully charge the ignition battery.  I'm thinking, put in a 16 volt for the ignition, and put an inverter off of the 12 volt to charge the 16.  Replace the MSD6 with a Jakobs, 3 batteries altogether, keep the same optima on the pumps.

Steve