ignition!!!! 20 44 vs 10 plus???

2cents

I'll throw my 2 cents in. i run a 10+ box on my whipple charged chevy. 557 ci and 45 lbs of boost and have had zero problems with reliability. I have never run a mag on this combo, so I'm not going to swear that it wouldn't make more power. I will say this, there are 2 camps on this. Most that are in the "mag camp" have never run anything but a mag. There's just a mind set that blown motors should run a mag. John Scialpi, pro-mod engines builder ran Crane hi-8 and switched to a mag 44 when they restricted pro-mods to 20% overdrive because it made 12 lbs more torque on the dyno. i wne t with the 10+ box originally becasue their were more timing control options available. Now that MSD has come up with the new mag controllers and you can even use the digital 7 to fire the mag w/ slew rate rev limiter, not sure which way I would go, except to save $1500-2000 by using the 10+.

 

msd 10 plus

well thanx 4 all the information everybody. i guess ill fine tune all the fuel system some more ,but it seems like the more i lean it out the faster it goes, which is correct but im already at a 175 main jet??? seems odd right?? can you see me with a 195 or a 205 main jet running 4 teens ?? if i go up on blower and fatten it up i ll proablly still be around 170 to 180 on a decent set up because im still way!!!! way!!! fat right now!!!!thanx dean

 

I would suggest sending it to Oddy . He has probably built more blown bbc's than anybody . The money you spend with him will be nothing compared to more wasted trips to the track and possible parts breakage . What type of heads are on the engine ?, I have not seen them mentioned .

 

10 Plus

The Heads Are Rher And Morrison Dart 360 . When I Tore The Motor Down This Winter Everything Looked Beautiful!!! Pistons ,rods , Bearings,you Couldn't Ask 4 Anything Better????crazy Huh? Tell Me This Though My Egts Are Reading Between 1000 And 1100 At The Finish ,which Is Where You Want To Be Right?? But My Plugs Are Showing Im Way Fat Still?? Could It Not Be Burning All The Fuel And Pushing Unburnt Fuel Past The Egt???showing A False Reading Higher Than It Supposted To Be??? Thanx Dean

 

Msd 10

The Last Pass On The Cars Set Up Was Shift 7200 Timing At 32% Bv At 78%leakage 175 Main 60 Hs And The Plugs Are A Little Black But Absolutely No Cadium Gone And Crossed At 1066 Egts . Ran 432 At 161. But My 60 Ft Times Are Poop . 1.048 To A 1.035 What A Slug Off The Line Huh!!! COULD IT BE IM NOT PULLING ENOUGH OFF THE HIGH SIDE???

 

Msd 10

What Is A Reasonable Amount Of Timing 2 Run ?? What Is The Average On A 540 W/ H Helix, 11.5 Comp. Is 32 Babying It ??? Ive Heard Your Not Supposted To Run It Like My S/c Car Around 36/38 It Is Hard On The Rods And Crank ,correct Thanx Dean Or Maybe Cause I Dont Have A Mag I Need To Crank The Timing Up?? The Cam Is In At 110.5 % Or 33% At 50 Thous Lift

 

What heads are u running?

 

msd 10

rher and morrison dart 360 s

 

Dean, we have a customer that runs an almost identical engine as yours. Its a 540 BBC, 12.4 to 1, CFE Dart 360's, and a Littlefield 8-71 HH with K-9 rotors. The blower is at 34% over. We put about 14 pulls on it at our shop in July. It was happiest when we ran 37 degrees in it. But we put it at 35 degrees because the customer is very new to blown alcohol stuff. We first dynoed it with a regular 10 box, then he wanted to put a 12 Amp mag on it, that he already had. The 2 ignitions made identical power. So he just stuck with the Mag.

 

Something is just not right with running a main jet that big with a 110 pump . The size of the hi spd is not the problem and i would not run more than 34* of timing even with the big chamber 360 head , although I am used to running with a mag .

 

On the dyno the above engine ( big chief small chamber ) ran great with 34* of mag . The more advance I put in the power just kept climbing . At the track with 34 deg. it would start detonating around 1/2 track and then lifter wheels would explode , pushrods were bending , jesel rockers breaking , exh. stand bolts coming loose and stripping out threads . Turned the timing back to 29 and it was happy all year with no parts breakage . Never ran a main jet bigger than 85 , hi spd 60 . These are just my experiences .

 

Msd 10 To Lonnie

Lonnie What Was The Jet Sizes In That Motor ?? Im Going To Look Tonite To See What All My Port And Hat Sizes Are .

 

The first mag I used in the engine was a super mag 3 and then later upgraded to a msd mag 20 . The static compression was 11.3 with a 72cc chamber . Even with the super mag 3 it would detonate and hurt itself with 34* of timing as the car went down the track but on the dyno it was fine . Ended up turning the timing down to 29* and leaning out the fuel system and never hurt another valvetrain part again .

 

Check the fuel return circuit.Check the idle check valve poppet to make sure it can be pushed down at least a 1/8 of an inch, and check for a restriction in the line,ie colapsed line,etc. If there is a restriction it wont matter how big a main jet you have!

Dale

 

please don't take this as a smartass comment, but are you sure you only have one jet in there? I've seen guys stack jets on accident, and only the smallest one applies, so you could wind up with big jet size changes, but not motor change. Anyway, something to double check.


bryan brown

 

10 plus my nozzle area

in the hat is 56 54 52 48 . #1 is a 60 3 -44 5- 40 7 -38 2 is 70 4 -46 6-40 and 8 is 38 how do you figure out the rest ?? main jet 175 high speed is 60