2nd gear launching?

[Hemiride]

Because it seems that when launching at the track the car over revs from 1st to 2nd grear, is it safe for the transmission to leave in 2nd and then let it shift automatically after that?

 

[Jack_Toepfer]

2nd gear launches were actually recommended some time ago. The car starts in 2nd gear in ECO mode by default.
Is your car stock, and what makes you think it's over revving from 1-2?

 

[MiHiHemi]

I've had some of my best times launching in 2nd. Definitely worth experimenting with.

 

[Usmc341]

I've always got my best 0-60 launching in 2nd. Even with 2.62 1st gear is extremely low.

 

[GBLWRMR]

I've also only had traction when launching in 2nd. ...And when I say "launching".. it's still only a 1300 rpm hit.

 

[Magnified]

I had tried this back about 2 years ago with no discernible effect, but then I did not delve deeply into it. I think I will re-examine this.

 

[Hemiride]

2nd gear launches were actually recommended some time ago. The car starts in 2nd gear in ECO mode by default.
Is your car stock, and what makes you think it's over revving from 1-2?

I'm actually referring to my son's charger HC. He has a innovators west lower pulley. Litens 2.72 upper. 1300 injectors pumps etc. It's tuned on E85. He uses HP tuners so while data logging it shows 1st to 2nd shifts at around 6900 rpms. 2nd to 3rd and 3rd to 4th around 6500.
I had read that because these cars rev so quickly in 1st that it's not uncommon for them to over rev from 1st to 2nd. That's why I posed the 2nd gear launch question. O forgot to mention he's running Micky Thomson et streets on back but now spins those like they were all seasons that come stock on kitty's
So is it safe for the trans to launch in 2nd ?

 

[GBLWRMR]

I stick with my "Yes. It's safe" from experience doing so on a stock car. I do not have any data logs or mechanical evidence that it's safe... just that it works.

 

[RGPIII]

Hopefully @HighHorseman or @Speedy! or others who drag race often will shed some light on this.

 

[Jack_Toepfer]

Thanks for the info, that changes my thought process.

Do you have a TCM tune? Are you running the car in a "TRACK" transmission setting?

Your tuner (your son's tuner) will need to see the log and see when the shift is being demanded and make sure the PCM and TCM aren't allowing the car to overrev.

I would not launch a high powered car - like your son's - in 2nd gear because of something that should be handled in the tune. 2nd gear launches are band-aids for stock guys on questionable prep. A car like your son's should be using 1st gear to get the most out of the first 60' ... I imagine he didn't build a 1000hp car to limp it out of the hole.

@curt_dusterhofftuning has done a lot of tuning in this area and may be able to share his experience.

 

[Hemiride]

Thanks for the info, that changes my thought process.

Do you have a TCM tune? Are you running the car in a "TRACK" transmission setting?

Your tuner (your son's tuner) will need to see the log and see when the shift is being demanded and make sure the PCM and TCM aren't allowing the car to overrev.

I would not launch a high powered car - like your son's - in 2nd gear because of something that should be handled in the tune. 2nd gear launches are band-aids for stock guys on questionable prep. A car like your son's should be using 1st gear to get the most out of the first 60' ... I imagine he didn't build a 1000hp car to limp it out of the hole.

@curt_dusterhofftuning has done a lot of tuning in this area and may be able to share his experience.

Yes. He has trans tune but I'm not sure it's all that good. Can a good tuner set different shift points by gear? Say like 6000 from 1st to 2nd and then say 6400 from 2nd to 3rd and 3rd to 4th?

 

[Speedy!]

If you're launching in 2nd gear it's because you have the wrong tires on the back.

 

[Speedy!]

Yes. He has trans tune but I'm not sure it's all that good. Can a good tuner set different shift points by gear? Say like 6000 from 1st to 2nd and then say 6400 from 2nd to 3rd and 3rd to 4th?

Yes, you can control RPM the car shifts per gear.

 

[Hemiride]

If you're launching in 2nd gear it's because you have the wrong tires on the back.

He's running Mickey Thompson et streets (?) On stock wheels.
Guess he's going to go with 17 in rims and slicks but still concerned about over revving 1st to 2nd

 

[Hemiride]

What is the factory shift points?

 

[Magnified]

If, as noted elsewhere, the motor's actually reving to 6900+ in first because the system can't catch it in time, something's wrong from a systems and control perspective. At least in my opinion.

 

[curt_dusterhofftuning]

I would not recommend launching is 2nd. It's hard on one of the stub shafts and have heard of failures from it.

I usually leave the 1-2 shift stock to avoid tagging the limiter there since the acceleration rate is so high.

 

[Speedy!]

Yep, if he's hitting the rev limiter with stickey tires on there the shift point on 1-2 is set too high. Back that down and you'll be good. Never seen good results from launching in 2nd.

 

[Hellcat Cuda]

I'm just now getting back into drag racing (with a Red Eye) after about a 45 year hiatus. Tires have really changed. I will say this, with my 305x18 MT ETrs, it's all about the burnout. Not too long but not too short, it's like being shot out of a cannon and she runs easy 10s (10.67 so far). If I screw up the burnout, it's a wasted run in the 11s. Gotta practice with and use my factory line-lock, but so far have felt too pressured to get to the line and stage.

 

[Jack_Toepfer]

He’ll want to talk to the tuner that did the TCM and share the logs with him. As mentioned previously, the shift points can be set as you wish. The PCM and TCM should work in harmony.

A 20” DR is probably not adequate for that car anymore.