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I have a Blown 548 with brodix big 2 heads ,and a BDS stage 4 8-71. I am switching to injected on alcohol with a Big & Ugly hat. I am using a msd 7-al box. How much Boost can I run before I need to switch to a mag. and what is the max timing on the 7-al with alcohol?

Thanks
 

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RAT PATROL
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I am just a hack, with a opinion.I am putting similar combo together
just less c/i and a bird.I think it is more of LIGHTing the fuel charge.
A decent mag will put x2 the amount of spark at the plug than the 7al
plus the msd will use at least 1 amp per 1000 rpms , so alternater may be needed.
alternater not needed with the mag,it makes it`s own
on the timing thing I want start out conservative and sneak up on it.
note:I am a new to some of this stuff.and I don`t know what your intened use is
we would like to see some pics.
 

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been there done this on many motors...forget the msd 7,8,10 or whatever...do yourself a HUGE favor and stick a msd 25 or 44 amp mag in there and be done with it if your on alky. you might get away with 10 lbs or so before you have tuning problems and shootin ducks ....but you will be chasing pills and nozzles forever when the only problem is the ignition.
 

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Gas likes the MSD, (big gap, quick rise time spark)because it lights easier. Alcohol needs the big mag (lower voltage, smaller gap, LONGER DURATION spark), at much over 6 to 10 psi depending on other factors, because you have much more quantity of fuel and it is harder to light. You can light paper with a match, a log requires a lot more heat to ignite it, but the log will make more energy in the end. TIMINATOR
 

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I am no expert on the max either, but I know for sure.....
This assumes you mixture is somewhat close.... if you are 30% fat God won't light it.....
You.. well, I have no idea what "you" can run... but "I, or We" ran 20# at The Cove. No evidence of misfire... either sound, or showing up on the data acquisition. Now, the mixture was good, plugs were showing a little heat, extended tip plug, etc. Your results may vary.
My big bitch especially with the mag thing and drag racing is they are more sensitive to idle mixture. Any hack can get an MSD piece to start and not touch the barrel valve. With a mag (especially a vertex if you call that a mag) they are much more sensitive. River runner... well, no big deal.
I run an alternator with a 7AL-2. The alternator was worth .1 ET. No shit. We had alternators fail, and sure enough we slow down .1. I'd not have believed it if I had not had it happen to me a few times over the years. Just a voltage thing I guess.
Wags
 

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I am no expert on the max either, but I know for sure.....
This assumes you mixture is somewhat close.... if you are 30% fat God won't light it.....
You.. well, I have no idea what "you" can run... but "I, or We" ran 20# at The Cove. No evidence of misfire... either sound, or showing up on the data acquisition. Now, the mixture was good, plugs were showing a little heat, extended tip plug, etc. Your results may vary.
My big bitch especially with the mag thing and drag racing is they are more sensitive to idle mixture. Any hack can get an MSD piece to start and not touch the barrel valve. With a mag (especially a vertex if you call that a mag) they are much more sensitive. River runner... well, no big deal.
I run an alternator with a 7AL-2. The alternator was worth .1 ET. No shit. We had alternators fail, and sure enough we slow down .1. I'd not have believed it if I had not had it happen to me a few times over the years. Just a voltage thing I guess.
Wags
yeahyeahyeah... but you got that double top secret triplewhammy delay box that does everything for ya... :D
 

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GN-- oh I am with you. A 44 will light anything. Fuel guys are around what?? 100 gpm pumps now?? Something around there.
I think a 7AL is an excellent ignition. A mag is needed is some situations. Well, many applications. But is the "average bad ass" river boat, or under Pro Mod stuff, it is just overkill. If a guy wants to spend the money, go for it. Just not "necessary".

BP-- I forgot to mention the small reactor I had build into the black box to light the fuel. LOL
Wags
 

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I have a Blown 548 with brodix big 2 heads ,and a BDS stage 4 8-71. I am switching to injected on alcohol with a Big & Ugly hat. I am using a msd 7-al box. How much Boost can I run before I need to switch to a mag. and what is the max timing on the 7-al with alcohol?

Thanks
We're kinda new to blown alcohol and running a similar combo, 565 BBC w/8.71/Bird in a flat. We're using a MSD12 with great results but only run about 5-6 lbs boost. We set our timing to 33-34 degrees and never change it.
Also, I agree with Wags on the big mags. Anything below 1500 HP a 44 is way overkill unless you need to do some welding between rounds. However, on the flip side, usually you can find 44's easier in the used market on sites like inside top alcohol dot com....
 

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Also, I agree with Wags on the big mags. Anything below 1500 HP a 44 is way overkill unless you need to do some welding between rounds. However, on the flip side, usually you can find 44's easier in the used market on sites like inside top alcohol dot com....
Besides the fact that the 44 is down right lethal, if you don't need that much power, all it does is eat spark plugs. Like David said, the thing is nothing more than a mini arc welder.



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Besides the fact that the 44 is down right lethal, if you don't need that much power, all it does is eat spark plugs. Like David said, the thing is nothing more than a mini arc welder.
my digital 7 does a real good job doing that. :D
 

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And it doesn't use 44 amps primary current. More like 1 amp per 1000 Rs
true. all i know is, it eats 'em up a whole lot quicker with the dig 7/trigger/hvc, than it did with the 7al2/blaster/billet dist... don't care to buy plugs by the crate...:)
 

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This may seem all too simple but....in days of old Sunny Jones, Marvin Savage and all the other guys ran Mallory Super Mag II's. Cuz that is all there was. Now they pushed 160 mph with those. I always figured then that I was ok on spark till I hit 160.
Super Mag II & III is what I have always run trouble free....for a hell of a lot less money.
Just sayin.
 
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