4wd Launching

Kxc · Nov 15, 2016

Headed to the track this weekend for a bracket race... How do you guys launch? With the mods in my sig how likely am I to break something launching in 4wd multiple times? Previously I left with the E-locker engaged and just power braked to about 10 psi boost, I have herd that this can cause de-fueling. My best with that strategy was 13.78 at 98mph with 1.85 60 ft. on tie-rant tunes and stock turbo .Tried a few light launches with starting in manual in 2nd gear and that seems to leave way quicker. I have one of Middwesttts tunes in there now for the bigger turbo and the shifts are firm as hell. 5th gear seems to have a whine/howl to it (possibly slipping?) Thoughts???

sootie · Nov 15, 2016

dont use the e-locker. start in manual mode 2nd and then bump the shifter to D. Or else pay Morgan to write you a track only tune start starts in 2nd with the lever in D. Use 4x4 hi and brake boost to 1800 rpm. you should be at least in the 1.7x 60' range. Keep upping the launch rpm until the truck starts hopping.

Kxc · Nov 15, 2016

Good stuff. The "Morgan budget" has been depleted until 2017... unless OUO Trac bars go on sale ....

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Six_Sloww · Nov 15, 2016

10 psi is a pretty soft launch, like Ron said stage using rpm instead of boost, you'll get a more consistent launch that way.

You would know if the truck was defueling, the pedal basically goes dead for a moment.

04cr450 · Nov 15, 2016

Cya this weekend op!

Kxc · Nov 15, 2016

Six_Sloww said:
10 psi is a pretty soft launch, like Ron said stage using rpm instead of boost, you'll get a more consistent launch that way.

You would know if the truck was defueling, the pedal basically goes dead for a moment.

I def didn't feel it so I guess not. Thought maybe it was minor defueling or timing thing.

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Kxc · Nov 15, 2016

04cr450 said:
Cya this weekend op!

Hell yea ! Are you racing ?

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04cr450 · Nov 15, 2016

Not racing. Have a hard time beating up my brand new truck hahahaha

Sterling6.7 · Nov 15, 2016

Six_Sloww said:
10 psi is a pretty soft launch, like Ron said stage using rpm instead of boost, you'll get a more consistent launch that way.

You would know if the truck was defueling, the pedal basically goes dead for a moment.

If you pull the front wheel sensor, will it still defuel under this driving condition?

Six_Sloww · Nov 16, 2016

Sterling6.7 said:
If you pull the front wheel sensor, will it still defuel under this driving condition?

If it defuels with advancetrac off then you have to unplug a wheel speed sensor

sootie · Nov 16, 2016

i simply dont see the benefit of using the e-locker at all. Its not like a tune only truck has the power to spin more than two of the four tires at any given time anyway :shrug:

Six_Sloww · Nov 16, 2016

sootie said:
i simply dont see the benefit of using the e-locker at all. Its not like a tune only truck has the power to spin more than two of the four tires at any given time anyway :shrug:

My truck seems to do alright with an open diff lol.

Kxc · Nov 16, 2016

What do you guys think about the howl / whine I hear when it shifts into 5th at WOT ?

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Sterling6.7 · Nov 16, 2016

Clutches slipping

Kxc · Nov 17, 2016

Rad

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sootie · Nov 17, 2016

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ramonpowerstroker · Nov 18, 2016

Ehh I've literally put 100's of quarter mile runs on my truck, half of them on the bottle, my best launching rpm was 2500ish with drag radials on the truck, I like shifting my trans though because in D the transmission slips like no one's business. I don't use the elockers, and I'd usually shift around 3200rpm on no spray and around 3800-4000rpm on spray. I'd like to get to a track where times are working, but at any no prep meets I've been in the top 3.