What rpm should I launch my car at?

[T2NR]

I'm going back to the track friday with drag radials. I have a bone stock ls3. What rpm is a good starting point? Thanks!

[SS_Dave]

Watch these two from Andrew...

https://youtu.be/ywSxWyGEo4o?si=99g3MMCp92iD79cI

https://youtu.be/Po2YnKflSfM?si=SyxEkksi3m8r5L9Q

[T2NR]

Originally Posted by SS_Dave

Watch these two from Andrew...

https://youtu.be/ywSxWyGEo4o?si=99g3MMCp92iD79cI

https://youtu.be/Po2YnKflSfM?si=SyxEkksi3m8r5L9Q

Thanks for the reply! I have watched those videos a few times in a row. They are good. I'm not using the e brake staging method though. Last month I just focused on getting farmilliar with a manual at the track. I'm going to have drag radials. So I was just looking for a good suggestion for launch rpm. I'm going to stage without launch control or two step. I'll figure it out after a few passes. Andrew's information is awesome and covers a lot of area with a broad stroke. My car is stock with good tires. I was thinking 3800rpm and see if that's too low? With the street tires (last month), there was no launching isht...

[SS_Dave]

If you're a stick car, and I assume you are since you said LS3, I think the e-brake method is quite valuable. And it's much easier to balance/control than trying to run up RPM while holding clutch and foot brake. If you just run the RPM up and then dump the clutch (or close to it) that shock to the drive train is super rough and the very reason you see a bunch of people complaining about broken axles or other parts.

[T2NR]

Originally Posted by SS_Dave

If you're a stick car, and I assume you are since you said LS3, I think the e-brake method is quite valuable. And it's much easier to balance/control than trying to run up RPM while holding clutch and foot brake. If you just run the RPM up and then dump the clutch (or close to it) that shock to the drive train is super rough and the very reason you see a bunch of people complaining about broken axles or other parts.

Yep, it's a stick car. I've got several passes at the track launching it "manually". When I take off, I don't dump the clutch. I have my left foot just almost catching the clutch after the second beam is lit. Then modulate clutch pedal release . Never dump it. I did get some 2" headers for my car today. So I'll have them on for next month.

[sr530]

With a 3800rpm launch, a 425ftlb engine is only making at most 308hp. Bump that 3800rpm launch up to 5000, now that 425ftlb engine is launching with 405hp.

If you want to take advantage of a 5000rpm launch, add a clutch hit controller!

Your radials will need to dead hook. Beyond that, the car needs some time to gain speed before the clutch locks up. If the car doesn't have enough time before the clutch locks up, the engine will bog. A clutch hit controller allows you to launch from a higher rpm without shocking the tires loose or breaking parts, it also gives you control over how long the clutch slips. And it does it with far less wear/tear on the car/clutch than you trying to do the same with your foot!

Grant

[acammer]

It'll probably need 5000+ rpm when you really get everything working well, especially with stock gearing. You'll need 0.5-1 second of slip with the engine RPM around peak torque, assuming the track surface is there to take it. Clutch hit controllers are great tools with radials, but the stock clutch is pretty easy to modulate and can probably get you some pretty good 60' times once you get yourself dialed in.

I do suggest some preload, both to limit breakage potential, but also to ensure consistency. If you're not using preload when you're full staged, you're either creeping out of the beams, or you're far enough off the edge of the friction zone where you're going to bump into it, rather than being right on it when you're ready to go.

I appreciate that it's another step to add to an already business few moments behind the wheel, but I really encourage routine for drag racing. If you do the same steps, in the same order, at the same points, all the way from the staging lanes to the timing shack, you'll eliminate variability and improve consistency. The cool thing is, you can get the routine dialed in on the street for the most part, and then implement it fully at the track. That way you show up ready to rock.

[Barnald]

Am I missing something? Why not use launch control? It’s a good place to start and get the feel for things plus it’s fun. I’m just a weekend warrior and it works great for me. Win some lose some but always fun.

[SS_Dave]

Originally Posted by Barnald

Am I missing something? Why not use launch control? It’s a good place to start and get the feel for things plus it’s fun. I’m just a weekend warrior and it works great for me. Win some lose some but always fun.

Probably mainly because it launches at like 2000rpm and most feel they can do better on their own.

[Barnald]

Originally Posted by SS_Dave

Probably mainly because it launches at like 2000rpm and most feel they can do better on their own.

It’s about 4000 rpm and it’s adjustable.

[SS_Dave]

Originally Posted by Barnald

It’s about 4000 rpm and it’s adjustable.

Can you elaborate how? HP Tuners only or...?

[Barnald]

Originally Posted by SS_Dave

Can you elaborate how? HP Tuners only or...?

Maybe someone smarter than me can elaborate better but my car was preset at 4200 RPM. My understanding is some cars can be adjusted by the driver using the settings on the car. But for sure a tuner can adjust it.

When all the work was done to my car, the builder said leave it unless I’m going pro….lol. It really is fine for the uninitiated and fun trackers like me cause even at that RPM it’ll pin ya back a bit. My only thing, and it’s not a big deal..I wish it would work in 2nd gear to save a shift. That first shift comes on real quick with 3:91’s.

[acammer]

Originally Posted by Barnald

Maybe someone smarter than me can elaborate better but my car was preset at 4200 RPM. My understanding is some cars can be adjusted by the driver using the settings on the car. But for sure a tuner can adjust it.

When all the work was done to my car, the builder said leave it unless I’m going pro….lol. It really is fine for the uninitiated and fun trackers like me cause even at that RPM it’ll pin ya back a bit. My only thing, and it’s not a big deal..I wish it would work in 2nd gear to save a shift. That first shift comes on real quick with 3:91’s.

They are all present at about 4200. It's not just a rev control, but it modulate the throttle blade with the clutch release, and what it sees for available traction. All of that is designed to work around a known tire compound, gear ratio, and power train - and all of that on pavement. As soon as you start to change anything about the car, and/or take it to a sticky drag strip, the viability of that factory launch control is out the window. A good driver even with everything being stock will stand to get more out of the car with it defeated. It guess it's fun to mess with when the car is stock, but once you start in on the mods, it just doesn't have the capability to produce really good results.

A second gear start would really slow the car down. Generally speaking, unless they've got a PD blower installed that makes tremendous amounts of low end torque, these cars actually need quote a bit MORE starting line ratio. For context - my car hooks well (on good, drag-specific tires) with a 4.63 rear gear and the standard SS "M10" ratio set with a 3.01 first gear. So that's like a 13.9:1 starting line ratio. The 1-2 shift definitely comes up quick!

[acammer]

Originally Posted by Barnald

Maybe someone smarter than me can elaborate better but my car was preset at 4200 RPM. My understanding is some cars can be adjusted by the driver using the settings on the car. But for sure a tuner can adjust it.

When all the work was done to my car, the builder said leave it unless I’m going pro….lol. It really is fine for the uninitiated and fun trackers like me cause even at that RPM it’ll pin ya back a bit. My only thing, and it’s not a big deal..I wish it would work in 2nd gear to save a shift. That first shift comes on real quick with 3:91’s.

They are all present at about 4200. It's not just a rev control, but it modulate the throttle blade with the clutch release, and what it sees for available traction. All of that is designed to work around a known tire compound, gear ratio, and power train - and all of that on pavement. As soon as you start to change anything about the car, and/or take it to a sticky drag strip, the viability of that factory launch control is out the window. A good driver even with everything being stock will stand to get more out of the car with it defeated. It guess it's fun to mess with when the car is stock, but once you start in on the mods, it just doesn't have the capability to produce really good results. It cannot be changed through any currently available tuning software, including HPTuners.

A second gear start would really slow the car down. Generally speaking, unless they've got a PD blower installed that makes tremendous amounts of low end torque, these cars actually need quote a bit MORE starting line ratio. For context - my car hooks well (on good, drag-specific tires) with a 4.63 rear gear and the standard SS "M10" ratio set with a 3.01 first gear. So that's like a 13.9:1 starting line ratio. The 1-2 shift definitely comes up quick!