Freestyle Epic curve thread

Pablo

Pablo

sqeez bth levrs & lean bk
Site Supporter
Location
georgia
I just bought my second Epic cdi, but this time I purchased the software as well. I had Art (Jetworks) program my last one and it worked flawlessly. I'm looking to get input from those who have found curves that work well with their setup.

Please post the following:

1. Epic curve and/or numerical curve settings
2. Engine/pump/ski specs
3. Flatwater or Surf riding
 
Q

QJS

X-
Location
GONE
Capture.jpgJust to get things started, this one was for a 5mm stroker with a dry pipe with a compression ratio of 14:1 running on pump gas.
Chris.
 
W

waxhead

wannabe backflipper
Location
gold coast
Here is the curve I run on all my customers engines. You need to jet your engine correctly to take full advantage of this curve. You need lots of fuel down low, it will hit very hard
waxstdcurve.jpg
 
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Pablo

Pablo

sqeez bth levrs & lean bk
Site Supporter
Location
georgia
What is the benefit of having a different rate at which max timing advance is incurred? In other words, why would Wax have his max timing advance onset at 1500 RPM where Chris has his max onset at 3000 RPM?
 
W

waxhead

wannabe backflipper
Location
gold coast
Ok I will explain it
As you may or not know a carb runs behind airflow in an engine. When you crack the throttle open it waits for the air speed to come up before it can pull hard enough on the jets to make the fuel flow. this happens very quickly but it does happen. The way around this is to run alot of fuel in the low circuit so that when you crack the throttle you already have the fuel there. It has the added benefit of cooling the cases giving you a sustained torque hit as well.
The downside of doing this is plug fouling and the way to get overcome it is by running more ignition advance down low. Its perfectly safe as the throttle plates are closed so your volumetric efficiency is way down and there for your dynamic compression is also down. It makes them 4 stroke down low but when you hit the throttle ohhh baby it smacks on very hard.
The throttle response by doing this is way up on a normal curve jetting combo. Have a talk to eric malone and see if you can see what his ignition curve looks like
 
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sportfish258

sportfish258

QJS said:
View attachment 146283This one is for an 865 ss with a B pipe cranking about 180. Pump gas.
Click to expand...

I think before messing with curves there should be some " safety " ground rules set . Cue us in the DON'T dos when using the epic programming . I know there are a lot of variables so set them basic for pump gas and race gas . That way we know some parameters to stay within .
 
2

2XLR8

X-
waxhead said:
Ok I will explain it
As you may or not know a carb runs behind airflow in an engine. When you crack the throttle open it waits for the air speed to come up before it can pull hard enough on the jets to make the fuel flow. this happens very quickly but it does happen. The way around this is to run alot of fuel in the low circuit so that when you crack the throttle you already have the fuel there. It has the added benefit of cooling the cases giving you a sustained torque hit as well.
The downside of doing this is plug fouling and the way to get overcome it is by running more ignition advance down low. Its perfectly safe as the throttle plates are closed so your volumetric efficiency is way down and there for your dynamic compression is also down. It makes them 4 stroke down low but when you hit the throttle ohhh baby it smacks on very hard.
The throttle response by doing this is way up on a normal curve jetting combo. Have a talk to eric malone and see if you can see what his ignition curve looks like
Click to expand...

Could it be possible that you could be feeling a slight hesitation or delay of power that makes you think that it just hits harder.
 
W

waxhead

wannabe backflipper
Location
gold coast
The curve I am using is pump gas safe. You will have no issues with it at all. Try it you may get a suprise
 
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munki63

munki63

Epoxy is my duct tape
Location
Canada
waxhead said:
The curve I am using is pump gas safe. You will have no issues with it at all. Try it you may get a surprise
Click to expand...
Ive got a few curves from ATP & XMetal and neither are as aggressive as yours and some are race gas highest advance is 30 on the race gas, 27 for the pump gas curve....just a thought
 
W

waxhead

wannabe backflipper
Location
gold coast
munki63 said:
Ive got a few curves from ATP & XMetal and neither are as aggressive as yours and some are race gas highest advance is 30 on the race gas, 27 for the pump gas curve....just a thought
Click to expand...
Im not going to talk for other engine builders but this is what I run on my engines that I build for my customers.
Have a look at the curve atp posted above its got higher advance than my curve so Im not sure what curve you got from them.

You need to also understand that when you dont have the throttle wide open that your dynamic compresion ratio is alot lower than when you have the throttle wide open. There for you are alot further away from the detonation threshold than if you were holding the same timing with the throttle wide open. If you ride a ski with a tacho you will see that as soon as you grab the throttle the revs will hit the 5000 plus range instantly this is why I pull the timing out up top sharply. The high advance is there just to get the engine up on the pipe in a hurry. I build my engines and tune my engines for the fastest possible throttle response, this is one of the things I do to achieve it
 
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