Circle D converter- how to launch?

[iamdub]

When the time is right, I'll be running my Tahoe to compare to the baselines I made before I did the cam, exhaust, converter, etc. I have a little time to get everything ironed out and launching with the new converter is my current thought.

It seemed to launch harder with the stock converter with a little brake-torquing. I've tried both ways on the street with the new converter and it feels like it does better with no or very little brake-torquing. It's hard to say for sure since it lights up the tires (Traction Control and Stabilitrak off).

It's Circle D's 278mm HP 4L60 LS converter, 2600-2800 stall: https://www.circledspecialties.com/4l60-hp-series-278mm

Anyone have any input on this converter or similar?

 

[Mechanic421]

You just have to feel it out. At the track you can watch your 60 ft times.

 

[iamdub]

You just have to feel it out. At the track you can watch your 60 ft times.

Of course, that's the default plan. I just wanted to be as cocked and loaded as possible in case I don't get many runs in.

Although, after some more thinking, it being softer off the line with brake-torquing may be Torque Management holding it back. Assuming my trans has 200K miles on it, I had the tuner leave a good bit still in it. If anyone else has a similar setup, they may have more or less TM in their tune so comparing to them is null. Maybe flashing it off the line "tricks" TM so it doesn't kill it as much.

 

[randeez]

the best 60' i could get with similar converter (for 6l80 tho) was to do it all in a single motion.

holding brakes, stomp gas, let rpm get up to around 1500-2000 and let off the brake, you want it to flash

getting the rpm up to 2000rpm and just hold it there waiting on the lights to drop always made for a slower 60'.

 

[gooffeyguy]

What randeez said.

I have no experience with launching these trucks at the track, but my 2002 mustang with the 4r70w trans gets better 60's by letting the converter flash

Sent from my SM-G930V using Tapatalk

 

[Chert_Detective]

Torque management will play a huge factor like you said. My 60' should be AT LEAST what Randeez was on his 12sec pass, but so far is .1 slower. I didn't get enough passes to really play around with it but depending on the converter, powerband, and torque management it will either like to be flashed as he described, or pedal to the floor and let off the brake.

If pedal to the floor is something you're going to try, don't just foot brake it. Get reaction time out of your concerns and focus on the launch. After you're fully staged put it in neutral and while 100% on the brake, rev it up around 3-4k and feel the brake pedal suck to the floor. When rpms drop to idle put it in gear and stomp it. Let off the brake when you're ready. I can take my 3400....to 3400, and not push through the brakes, im excited to see what the 4600 does.

 

[iamdub]

the best 60' i could get with similar converter (for 6l80 tho) was to do it all in a single motion.

holding brakes, stomp gas, let rpm get up to around 1500-2000 and let off the brake, you want it to flash

getting the rpm up to 2000rpm and just hold it there waiting on the lights to drop always made for a slower 60'.

I'm trackin exactly what you're describing. I've tried that on the street with the stock converter and it did great. It's another way to sneak around Torque Management.

Torque management will play a huge factor like you said. My 60' should be AT LEAST what Randeez was on his 12sec pass, but so far is .1 slower. I didn't get enough passes to really play around with it but depending on the converter, powerband, and torque management it will either like to be flashed as he described, or pedal to the floor and let off the brake.

If pedal to the floor is something you're going to try, don't just foot brake it. Get reaction time out of your concerns and focus on the launch. After you're fully staged put it in neutral and while 100% on the brake, rev it up around 3-4k and feel the brake pedal suck to the floor. When rpms drop to idle put it in gear and stomp it. Let off the brake when you're ready. I can take my 3400....to 3400, and not push through the brakes, im excited to see what the 4600 does.

I plan to stage and wait until green to even start with the foot braking. This is how I'd get past that "gotta rush and launch before green" mentality. I really don't like foot braking an essentially stock trans and converter, so I'll try this once or twice, but should only need to try it once to know and compare. Besides, TM would just kill it if it did launch harder.

I have a feeling my best bet is to flash it. Easier on the drivetrain and doesn't let TM see anything it needs to "manage".


Thanks for everyone's input!

 

[09_4WD_YUKON]

What part of LA are you in? I'm in Walker.

 

[iamdub]

What part of LA are you in? I'm in Walker.

West Baton Rouge, a few miles north of State Capitol Raceway. I know a couple people in Walker. You know a Tracy with a 'bagged satin black OBS extended cab? Or Ramon with a Graystone Metallic Tahoe, static slammed on (I think) 26" billets?

 

[09_4WD_YUKON]

Nah, I don't get out too much. I may have seen them around tho...Walker/Denham not the big of an area! LOL