New Cams New Thread

[Claviger]

Soon....

 

[Claviger]

It didn't do what was expected, but still did well. Will post a graph when I get home, happy knowing it's more reliable and I didn't backslide at all on power.

 

[Claviger]

To alleviate the suspense:
256whp
190lb-ft
10-15 lb-ft gain from 4000-6400, dips in curve are much less pronounced.

Peak HP actually will come somewhere over 8000 now, but I only turned it 8000 for longevity.

 

[ozrider]

To alleviate the suspense:
256whp
190lb-ft
10-15 lb-ft gain from 4000-6400, dips in curve are much less pronounced.

Peak HP actually will come somewhere over 8000 now, but I only turned it 8000 for longevity.

That's still pretty respectable and get your attention

 

[Claviger]

We found a new limit. There's more than 256 to be had, that's all that could be made today, will explain when I get home.

 

[Claviger]

Ok regarding post #193, we were comparing the wrong graph to today so throw all that dip changes out. The below graph was from today, I'm posting it to demonstrate the limitation we ran into. If you look in the yellow circle, you'll see a very abnormal dip, that's an ignition miss.

What was happening is when the bike was heat-soaked, it wouldn't miss at all and would max out at 254/188, and still not be at the plateau expected at peak HP by 8000. When we let it sit to bring coolant temps down to 90-92, as is typical when checking final power figures, it would randomly ignition miss somewhere in the pull, 2,3,4 times, non-repeating RPMs, could be 3800, could be 7000. We tried 3 or 4 times, every time the bike made 256/188, but every time misses moved. Then without restarting after it had heat soaked, we'd do a pull and come up with 254/188 with no misses anywhere... strange right?

Well, Nels is highly confident what's happening is one of the coils isn't able to fully light a spark when the bike isnt totally heat soaked. Hotter chamber = easier to light, so the spark power is enough, but, when cool it simply doesn't have the power to fire it off properly. Makes sense because, if the crank trigger was causing the missing, the WinPEP7 software wouldn't be able to plot the power (it does), if it were a cylinder preigniting/detonating the AFR would wildly swing as a result (it doesn't), and if it were a timing table error it should show up consistently at the same RPM (it doesn't). So, next upgrade is going to be MORE SPARK The only other vehicle he's seen do this is LS1/LS2 based high strung NA builds, similar ignition system, similar failure, solution with MSD ignition box to give a lot more spark energy. Bad PC-V.

Trace out the HP line and you'll see it clearly wants to make around 260-265 at 8200 or so, just couldn't get there today, red is today, blue was previous build:
Yellow Circles = miss
Red Circle = Nels backing off throttle a bit


This chart of today alone really shows the top end taking off at 7300 on power and they ending before peaking:


The bike makes more torque everywhere below 4,000 (though it's not reflected on this particular pull) and a TON more under 2,500 than before.

EDIT: Removed incorrect info.

On the search now to solve coil power and get big spark into the chamber my bad PC-V.

 

[Claviger]

Ultimately, any change in power curve is a bonus, the real win is that I didn't go backwards on power, the bike feels 100x better to ride, and went way forwards on valve-train reliability. It also validated my handy work by not exploding weeee

Other secondary big wins, now I know the following things, and know where to focus to maximize the current parts:
1: Cams are not my bottleneck any longer.
2: Intake and Exhaust are not my bottlenecks (they're sized to support another 25whp easily).
3: The airflow bottleneck is intake port or exhaust port or both, valves aren't yet choking the motor at 40mm/32mm.
4: The biggest bottleneck at the moment is the ignition system failing power commander.

 

[Claviger]

You can see the miss at about 6.5 seconds in, watch the license plate, it drops a split second = miss.

 

[Claviger]

Measured all coil primary secondary, they check out.

Maybe time to give stock coil setup another try....

Anyway, that's that for new cams, they're in, they work, they still have more to give.

Final point: 450cc injectors at 4BAR (531cc tested), were at 91 duty cycle at peak hp.

 

[Kevin frazier]

Awesome job man