mag 20 vs. mag 4

I am trying to find out what kind of difference a msd mag 20 from a mallory mag 4 will make.I run a pro mod blown alcohol hydro drag boat.I have had no problem running the numbers but am inconsistant.I have been told the timming does not stay accurate with a mallory.I am also getting a data system and they told me the mallory makes to much noise to work with the computer that is the main reason for the change.Any help would be appreciated.We get three rounds on saturday to try to get this figured out and qualify.

 

Mag-4 is a joke. We switched to a promag 12 and couldn't be happier.Using 24 volts it starts like a street car and burns a lot more fuel.BTW our mag 4 was properly serviced. We used a computer with the mallory and a msd tach/signal convertor.
Mike

 

we went from a mag 4 that was updated by Tom Cirello to 4.4 amps to a pro mag 20.......no comparison. we use 24 volts to start.......never had a problem.

 

What kind of numbers before and after?I am guessing 2 or 3 tenths.will it light with only 12 volts and a csi starter?

 

Our starts just fine with a Tilton 12v starter.

 

You can use a std 12 volts starter like csr or Tilton , but go with 16 battery
Claude

 

Interesting thread.
What performance gains could be expected simply by changing from a Mallory to a promag?

I run a Mallory 3 thats hopped up to 5amps. We are consistent with 7.1s in a small blown alcohol hemi.
If we change to a Promag 12, how much could we expect to scrub off the ET?
I assume we would need to change the fuel volume to allow for the better burn?

Cheers

 

Thanks for your input but,I really need to have an educated guess going to qualify and at this point I only have a guess not an educated one.I am sure someone has done this swap without any other changes.I am guessing tune as normal minus 3 degrees of timming.In the past with the mag 1V 1 degree usually equalls 1 tenth.Am I even close?

 

super mag to a msd promag

We were running a super mag that was putting out 5.7 amp's, blown BBC we run 6.30 at 225mph in the 1/4. we went to a 44 amp promag and from my base tune I just added .015 more to the main jet on the first pass, and it worked great, you will notices that the oil will not be all milky, the msd promag will burn a lot more of the fuel then the super mag did. If you need more info call Bob at B R motor sports 800 328 3333.
He has about the best prices on msd equipment . But this only my 2 cents GOOD LUCK. BUTCH

 

Thanks guys,I am going to try and put it all the same but 27* instead of 30*.Do you guys use a timming light to set the timming?I use to use a buzz box but,I don't think that works with msd.I have a mac light with a dial.Is that o.k.?

 

rpm makes a data logger for the mallory mag