Converter issues?

Hi guys. Question about this launch data. Attached is a rpm and timing graph from grid 3160lb drag truck B/A 565 and glide Arbruzzi converter. on brake at 2000 rpm pulling 14 off 28 and ramping back in over 1.3. Even tho timing comes in seems to be swimming in converter for 1.25 seconds before it starts to really accelerate. I know converter is somewhat tight but have plenty more power to add once we can get launch under control my concern is the flatline after converter flashes at 6k but rpm doesnt start to increase for 1.2... seconds Result was 1.13 60ft Didnt seem to be spinning but didnt really take off either Any ideas or opinions? Have tried to hit it harder just goes up in smoke. Just did new DA shocks but wont get a pass till spring

 

Why are you leaving so low? Nothing is in a power band that low? Your instantly pulling 14° at the button release? What is the low gear and rear gear? Something that heavy to me needs so rpm to get it moving. It's really hard to accelerate a tire that isn't moving to being with. There's no reason you shouldn't be able to launch at 4000-5000 rpms.

 

Hi Jay thanks 180 low and 4:56 on a 34.5 tire. Was new build as of last June so were still working some bugs out. Ive tried to hit it harder off line but just goes up in smoke. we are upgrading shock over winter. But looking at this data coundnt understand why the flatline for 1.2 seconds

 

Hey John, I only see a .2 sec flatline - not a 1.2? (somewhere around 1/2 second in)

Here's where it would be good to see DS speed. I wonder if the initial RPM ramp is just the engine zinging through the converter since you started at essentially idle. The DS speed ramp is likely nowhere near that steep.

It looks like the engine got caught by the converter, then probably spun the tires a little bit. I'm thinking that little dip at the blue marker is where it stopped spinning and hooked up.

When you "hit it harder", how much harder? We were playing with a friends blown SB car a few years back trying to get it to hook better off the line. We kept going down in launch RPM and it kept getting worse. We finally turned around and went up and it came around. We figured that that torque multiplication in the converter was actually making it hit the tire harder at the lower RPM. If that's the case, if you only hit it at 3000, you may have gotten into that area, where if you go up to 4-5000 it will be up to where the converter's tighter and might work better.