5050

Is there a certain point of performance where you have to or need to run an ignition box? Is 3 wire ready run sufficient?
604, 4.56 bore 4.625 stroke, 91 octane 10ethanol and 36 timing locked out, flat top je, dart big m billet caps, brodix bb3xtra partial cnc t&d shaft mount 1.7, Callies mag crank, ultra rods, arp studs, dart intake, quickfuel 1050, comp elite race solid rollers, comp solid roller cam .715 .715 260 268 @ .050 .018 lash 114 lobe sep. 1st engine is dyno. 2nd one next week[ATTACH=CONFIG]565408[/ATTACH]

BenPerfected

We have our timing set at full advance at 4000 RPM. Where the timing is from 1000-4000 RPM doesn't make much difference.

5050

That wasn't question. I'm running 36 degrees locked out with distributor no box. My question is the need for msd box or not?

kvogt

The multi spark boxes usually help clean up the in in gear idle on a deal like you have.

bck

If you choose to use a box, Daytona seems to be the way to go.

offshorexcursion

iTrader: (5)

Bck is correct.....Daytona sensors ignition will make you smile!

MILD THUNDER

iTrader: (3)

If things like Start retard, pre-selectable rpm based timing maps, programmable 2d and 3d timing maps, idle stabilization, built in easily adjustable rev limiter, data logging, and stuff like that gets you excited, the Daytona Boxes are great.

Sounds like you have some nice builds there. Assuming they are going in a 38 AVS scarab, probably with bravo based drives, I think I'd be looking for an igntion system that will help the engines behave around the docks nicely. The Daytona systems will allow some great tuneability at idle.

articfriends

iTrader: (1)

I would invest in daytona boxes with adjustable timing curve before i invested in ignition boxes as you will most likely pick up tq from 4000 to 5000 from having a actual timing curve vs all in. I have seen a noticeable difference on dyno on last few motors i dynoed, fwiw, smitty

5050

Thx. Yes they are going in 2001 38avs scarab. Motors idle pretty decent for what they are 114LS helps and torque carried up top. Should be a beast. Thx for comments and input.

MILD THUNDER

iTrader: (3)

Usually they idle really nice on the dyno, and then when ya put them in thr boat, and shift into gear, they wanna stall out.

One thing i noticed was going from locked at 34, to 18 or so in nuetral idling, was your eyes no longer watered and didnt smell like raw fuel fumes . 34 works really nice in gear under load.

The way me and icdeppl setup our carb blower engines, is they idle around 18* in nuetral nice and clean. When you shift into gear, and the rpm drops below say about 700-750, idle stabilzation kicks in, and raises timing to 36 deg to keep the engine from stalling. The beauty of this, is .....

Anyone whos ever adjusted a distributor on a carbed engine, knows that when you advance the timing , the engine revs higher. The rpm picks up.

The downside, is carbs are not efi. They dont have idle air bypass, nor can they compensate fuel based on load at idle. When you crank the timing up (locked out), you often need to close the throttle blades , to keep it at an acceptable rpm. Say your shooting for 1000rpm in nuetral.

Problem is, that works great with no load. You load the engine when putting it in gear, and all of a sudden, she either dies, or drops big rpm. So you fatten it up via the mix screws, so it wont stall. Then, back in nuetral, shes fat as fuk.

Advancing the timing pulls harder on the carbs . In gear, your afr might be 12.5:1. But when you put it in neutral, it might be 10.5:1. By being able to advance timing, when its in gear, can help narrow that range, and also, minimize the rpm drop, from neutral to in gear. Engines idling at 1100 out of gear, and a sputtering 600 in gear, are a perfect example. Being able to control the timing, you may be able to get a deal that idles at 900 out of gear, and 700-750 in gear.