Anybody drag race with an lbz??

[kevenneu]

Efi live with up to 150hp
No exhaust
Deleted egr
Guessing truck weighs around 4k.

Engine seems to run great, however transmission seems to shift lazy or engine seems to "outrun" the trans

With higher tunes it launches good, then it gets into this rhythm of defuel-shift-reapply power only to have to defuel for the next lazy shift. Sometimes it seems to take up to a second for it to decide to complete the shift and reapply power. Once it gets into high gear it pulls cleanly to the stripe.

I have another lbz dually with an edge 80hp tuner and it seems to do the exact same thing.
Needless to say this is killing my times

Anybody dealt with something similar? I plan on installing a transgo jr to see if that helps
Anything else I should do while i have the valve body off?

 

[kevenneu]

*edit. Truck weighs 5620!

 

[TheBac]

"Anybody drag race an LBZ".... thats funny. Most all of us on this forum either drag race or sled pull our trucks, so yeah. LOL

100hp over stock used to be the mantra before needing to build the Allison, but if you're racing on a stock trans, toss that out the window. You've hurt it and it needs to be rebuilt.

 

[PureHybrid]

Sounds like the transmission is hanging on for dear life. Contrary to popular BookFace belief, 100+ hp tunes are not "tranny safe"

 

[kevenneu]

It was 2 trips down the track. 1 at 70hp and 1 at 150. I believe the trans is fine so far. I'm going to put the trans go in it and am asking if there's anything else that should, or could, be done while the valve body is out of it...

 

[kevenneu]

Source: https://youtu.be/Ej5AaQwvOnE?si=7g1BqDsUhbKTEqJD

 

[kevenneu]

Ran 14.4 @99mph. It's just a cruiser but it would be nice to get it deep in the 13s

 

[Bdsankey]

Realistically that is just how stock programming works on the TCM side. The defuel and shifts tend to be very conservative to help keep the drivetrain alive.

A transgo jr will help but it won't resolve your issue overall. You could look at quickening up the shifts but that will lead to accelerated wear (typically) on the C3 pack. The C3 pack is the most overworked and undersized with only 4 frictions taking full power in 3rd and 5th gears.


You have nothing to lose with a transgo jr, I just want to make sure your expectations are realistic in terms of lifespan. A trans tune will also help greatly, not just in shift speed but also going to a 2nd gear launch will pick up quite a bit in the 60/short track.

 

[kevenneu]

Realistically that is just how stock programming works on the TCM side. The defuel and shifts tend to be very conservative to help keep the drivetrain alive.

A transgo jr will help but it won't resolve your issue overall. You could look at quickening up the shifts but that will lead to accelerated wear (typically) on the C3 pack. The C3 pack is the most overworked and undersized with only 4 frictions taking full power in 3rd and 5th gears.


You have nothing to lose with a transgo jr, I just want to make sure your expectations are realistic in terms of lifespan. A trans tune will also help greatly, not just in shift speed but also going to a 2nd gear launch will pick up quite a bit in the 60/short track.

Thanks, that's the info I was looking for. Not trying to set the track on fire but if i can do some easy cheap things to help it a bit thats what i want to do. The 2nd gear launch- can that be turned on and off with a switch? Or somehow be programmed into my 5 position switch? I also want to try to get my tow haul option back. I don't have a bcm anymore

 

[Bdsankey]

Thanks, that's the info I was looking for. Not trying to set the track on fire but if i can do some easy cheap things to help it a bit thats what i want to do. The 2nd gear launch- can that be turned on and off with a switch? Or somehow be programmed into my 5 position switch? I also want to try to get my tow haul option back. I don't have a bcm anymore

To gain tow-haul you'll need a BCM I believe.

It is a TCM tune and not something you can adjust with the ECM DSP5 switch. You would have to flash the TCM when you wanted 2nd gear start. If this was an OEM application, it could be toggled with T/H as those are different shift tables.

 

[Bbuchanan11]

Be careful with 2nd gear launch’s I ruined an older triple disk within like 3 launches… also assuming you are running a 6 speed lock out 6th gear. Less shifts and I believe hitting 6th wide open is not good for it.

 

[Dozerboy]

Are you running a lift pump?

4x4 right? Looks like your Tbars are al little high. CVs should be flat.

 

[TheBac]

Be careful with 2nd gear launch’s I ruined an older triple disk within like 3 launches… also assuming you are running a 6 speed lock out 6th gear. Less shifts and I believe hitting 6th wide open is not good for it.

I would never run a 2nd gear start on a stock converter, let alone a stock trans.

Im curious as to what gears are in the diffs on that truck, running what look to be 285-size tires? That was a very "lazy" start on that video run, even considering the lower hp.

 

[Bdsankey]

I would never run a 2nd gear start on a stock converter, let alone a stock trans.

Im curious as to what gears are in the diffs on that truck, running what look to be 285-size tires? That was a very "lazy" start on that video run, even considering the lower hp.

Smart idea? Nah, but it’s been done.

If he’s willing to risk a trans that already sounds tired, it’ll cut some tenths.


Sent from my iPhone using Tapatalk

 

[darkness]

I also want to try to get my tow haul option back. I don't have a bcm anymore

you can try a Kodiak tcm os to get tow/haul, but they are always in t/h. No bcm in the Kodiak.

 

[Bdsankey]

you can try a Kodiak tcm os to get tow/haul, but they are always in t/h. No bcm in the Kodiak.

His goal is for it to be a switchable thing like in the pickups. Oskar in Sweden has fought the same exact issue and has concluded that he needs a BCM to do it.

 

[PureHybrid]

It was 2 trips down the track. 1 at 70hp and 1 at 150. I believe the trans is fine so far. I'm going to put the trans go in it and am asking if there's anything else that should, or could, be done while the valve body is out of it...

Change over the shift springs to the white Ratiotek ones. That's about all you're going to be able to install without splitting the trans open...

Did you drive this on the street and let the transmission learn the power? If you just slapped a 100hp tune at it and made a pass it'll flare shifts

 

[2004LB7]

Ran 14.4 @99mph. It's just a cruiser but it would be nice to get it deep in the 13s

My time is identical but I have a 3k lb heavier truck. All stock except tuning and a built transmission. I agree that the launch in the video looks lazy. Do you have a time slip for that run? What was your 60' time? I'm going to guess your tune can use some refinement. And maybe even some tweaks to the transmission tune

If you don't have a built transmission, that would be my first upgrade recommendation

 

[JoshH]

I'm going to be the one guy that goes against the grain here. That truck weighing 5600ish lbs should have no problem getting deep into the 13s with good tuning and good setup on the truck. We were doing that back in the late 00s with crew cab short bed trucks weighing 1000+ lbs more even without a lift pump on the stock trans. It won't last forever, but for a truck as light as this, as long as the trans isn't already hurt, I bet it will last a long time. I would also not recommend transmission tuning to try to make it shift faster. That's a good way to cause tie-ups and break hard parts. These early six speeds don't get the benefit of raising pressure with trans tuning like the 2011+ transmissions do; the only real benefit to trans tuning on them is changing shift points and lockup for drivability or if you have bigger turbos that need higher RPM shift points. I say get your launches figured out, get some good tuning that you give the transmission time to learn before going to the track, get a lockup switch for the converter (DHD and Fleece both make good ones), go ahead and do the transgo jr and the ratiotek valve springs mentioned above, and see what happens.

 

[gmduramax]

Rail pressure holding?