Dyna 3000 curves

[KDIMD]

I have a supercharged VMAX and have been having heat issues. Also for the first time at WOT, bike actually died and after rolling in neutral, will start right back up via bump start. After some research, the issue may have been that the blown engine ignition needed to be retarded a bit.

Since I have the newer Dyna 3000, I am able to adjust the curves via software. Going off the old curves I had read on the older dip switch style dyna 3000 units, it suggested to set retard curve at 25 degrees BTDC. Not sure what that really means.

Anyway, when I hit the start button, the motor started almost instantly and idled with out dying. Before, I would have to hold the throttle open for a minute for the bike to warm up before it would idle and not die. I could only ride around the block so cant say how it performs.

Anyway, the preset map of the newer Dyna 3000 has the retard curve at about 28 degrees BTDC (see pdf of map). Can anyone tell me if 28 degrees is more preferable to the 25 degrees? I will try to take it for a longer ride on Sunday so want to have it set for either 25 degrees or 28 degrees, or will the difference be so small I wont notice.

Also, will retarding the ignition help on heat management? Also dying at WOT (will test on Sunday)?

Other engine mods - 4-2 dale walker exhaust. COPS with resisters. Supercharger. I generally use 95 octane.

 

[Supercharger]

I think your injectors can't deliver enough fuel at WOT.

 

[one2dmax]

Narrow the gap on the spark plugs as well. Maybe not over .025" to start with. You want to run as much timing as your fuel will allow without any spark knock.

 

[Fire-medic]

FYI he has a Gen 1, no injectors.

I think your injectors can't deliver enough fuel at WOT.

 

[Traumahawk]

Have you thought about putting it on the dyno, and trying different curves, and seeing what the bike likes?

I dont think the bike dying is due to the timing curve though.

I would start with the basics (after re-gaping the spark plugs per Seans recommendations) what is your fuel pressure?

 

[KDIMD]

Will do the spark plug gap. Not sure what the fuel pressure is. It has a big Holley Carb so thought maybe the fuel pump could not keep up with the fuel requirements, unless the fuel bowl is too small. But the fuel consumption should not be any different at a given rpm, just gets up the rpm limiter faster. Do I need a bigger higher flow fuel pump? I replaced it a few years back and have new filter and lines.

 

[AJBinVA]

You might need to see what pressure you're getting. The Holley carbs typically like around 7.5 psi 5 minimum. I think the stock pump is around 4psi I think? Maybe you're leaning out a bit due to low level. May need to set the floats a touch higher than recommended due to lean angle on a bike since it's a car carburetor. A good wideband would really be able to help so you can get some on road testing.

 

[AJBinVA]

Oh and you could also load in the pre programmed base map 5 or 6. If you don't have the instructions I can try and dig mine up.

 

[KDIMD]

Thanks. I have a laptop so will probably take it along and change maps. At least the tuner is easy to get at without the airbox in the way.

 

[KDIMD]

Based on what I can find, the vmax fuel pump puts out 2-4psi, while the holley carb is recommended at 6.5 psi. Would this be the problem, fuel starvation once the fuel bowls empty out at speed? I can purchase a new fuel pump, does it need a regulator or will any of the ones Holley sells on the Mity Mite line work? I should have enough space to fit one in.

 

[one2dmax]

Don't get too much flow and a regulator would be ideal (especially one that can return excess fuel back to the tank and prevent "dead heading"). I'm not 100% sold that's the issue just yet. I had a 1428 blower bike in the shop with stock pump that kept up just fine (we converted it to a weber)

 

[KDIMD]

Thanks Sean. Anyway, wont think about buying anymore parts til I am in the states in late Jan. Will do the gap first.

 

[MaxMidnight]

...thought maybe the fuel pump could not keep up with the fuel requirements, ...But the fuel consumption should not be any different at a given rpm

Is that last assumption correct?
I would assume that due to the pumping effect of the blower more air will be pushed into the cylinders than would normally occur and to maintain the correct air/ fuel ratio will need more fuel t achieve this.
On that basis more air = more fuel therefore fuel consumption will go up.

 

[KDIMD]

Regapped plugs, change Dyna map, and set the float on the carb, was too low. Now we have a typhoon rolling through the Philippines so will be a while before I can get some high speed runs in.

Merry Christmas and Happy New Year all!