Launch RPM's?
Launch RPM's? simple question what RPM do you launch at with slicks? im trying to figure out what i should be launching at. I have a C5 corvette M6 with a spec 3 clutch and stock 3.42 gears. car has a cam 234/238 with all supporting mods and make mean power between 3,500 and 6,500 RPM's. What RPM should i be launching at with slicks/MT E/T streets?
This is a huge blanket statement to get an answer from. Depending on power output@each individual rpm's, what the track can hold, etc. etc. etc. it's going to be different for everyone.
For example I have a stalled auto, I stall it to 3500-4000 on the footbrake and the converter flashes 5800-5900 off the hit. I run drag radials though.
The main thing is, you are running a slick. Slicks need wheel speed to get the car off the line quickly. You DO NOT dead hook a slick. You want it to slip/spin a little and transition to not spinning gradually. If you dead hook a slick or if you go from spinning/slip to hooking abruptly your most likely going to break parts, especially in a IRS vette.
All that being said, launch at a rpm that allows wheel speed to be built off the line and that still nets you a decent short time. Take some tire chalk or white paint and mark a swatch about 4" wide on the tire so you can see it spinning better off the line to judge just how much slip you are getting.
For example I have a stalled auto, I stall it to 3500-4000 on the footbrake and the converter flashes 5800-5900 off the hit. I run drag radials though.
The main thing is, you are running a slick. Slicks need wheel speed to get the car off the line quickly. You DO NOT dead hook a slick. You want it to slip/spin a little and transition to not spinning gradually. If you dead hook a slick or if you go from spinning/slip to hooking abruptly your most likely going to break parts, especially in a IRS vette.
All that being said, launch at a rpm that allows wheel speed to be built off the line and that still nets you a decent short time. Take some tire chalk or white paint and mark a swatch about 4" wide on the tire so you can see it spinning better off the line to judge just how much slip you are getting.
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This is a huge blanket statement to get an answer from. Depending on power output@each individual rpm's, what the track can hold, etc. etc. etc. it's going to be different for everyone.
For example I have a stalled auto, I stall it to 3500-4000 on the footbrake and the converter flashes 5800-5900 off the hit. I run drag radials though.
The main thing is, you are running a slick. Slicks need wheel speed to get the car off the line quickly. You DO NOT dead hook a slick. You want it to slip/spin a little and transition to not spinning gradually. If you dead hook a slick or if you go from spinning/slip to hooking abruptly your most likely going to break parts, especially in a IRS vette.
All that being said, launch at a rpm that allows wheel speed to be built off the line and that still nets you a decent short time. Take some tire chalk or white paint and mark a swatch about 4" wide on the tire so you can see it spinning better off the line to judge just how much slip you are getting.
For example I have a stalled auto, I stall it to 3500-4000 on the footbrake and the converter flashes 5800-5900 off the hit. I run drag radials though.
The main thing is, you are running a slick. Slicks need wheel speed to get the car off the line quickly. You DO NOT dead hook a slick. You want it to slip/spin a little and transition to not spinning gradually. If you dead hook a slick or if you go from spinning/slip to hooking abruptly your most likely going to break parts, especially in a IRS vette.
All that being said, launch at a rpm that allows wheel speed to be built off the line and that still nets you a decent short time. Take some tire chalk or white paint and mark a swatch about 4" wide on the tire so you can see it spinning better off the line to judge just how much slip you are getting.
sorry if i sound dumb about this but i promise i will learn fast
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Verdad Gallardo thanks for the knowledge i didnt know any of that... im just starting to learn how to properly run a 1/4 mile. I will be honest i have never ran a slick before so i am totally ignorant to the process... I thought i threw on the slicks, smoked them a bit in the water box, pulled up to the line, put it at 5K, drop the clutch Milli seconds before the light turns green, the slicks catch 100% (dead hook i believe is the term, right?) and off down the track i go. Your saying that in an IRS car if i dead hook then i break parts? so should i not be running slicks with an IRS???
sorry if i sound dumb about this but i promise i will learn fast
sorry if i sound dumb about this but i promise i will learn fast
Just because you have an IRS car doesn't mean it will break parts if it dead hooks. Just more prone to break like a 10 bolt rear end would be. Most all the guys that run manual transmissions run slicks for the fact that they aren't meant to be dead hooked(no spin). It's easier on parts with a manual trans car as the launch is much more violent than an automatic car, even one with a transbrake because the converter acts like a fluid filled shock absorber when the car is launched in an automatic car, whereas a manual has no give in the driveline. I didn't mean to scare you from racing your car as in racing things that are weak will break, and then you upgrade as each part will be tested to the max.
Hope this helps some. Ask as many questions as you need too.
^ you definitely do need something to give in a manual car or something will break.
Also, some slippage off the line is good because in a manual, if it doesn't slip, you'll just bog and it'll hurt your et.
You'll probably 60' fine but it will bog and your 330' will suffer bad.
Also, some slippage off the line is good because in a manual, if it doesn't slip, you'll just bog and it'll hurt your et.
You'll probably 60' fine but it will bog and your 330' will suffer bad.
PUt a 2 step in the car and just keep raising it, and drop the clutch, with gas to the floor... keep raising the 2 step until the car stopps bogging.
Be prepared to start replacing parts too.
Be prepared to start replacing parts too.
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Joined: Sep 2007
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From: hattiesburg, Ms
It will probably bog no matter what you launch at because of the 3.42's, i don't think you should launch it really high because you will be breaking parts if the rearend is stock. You really need a two step to help be consistent with the launch rpm's. I suggest getting a two step and working your way up in 500 to 1000 rpm increments from 3000 or 4000. Being able to data log wheel speed and rpm that the car stays at will help you learn what the car is gonna do.
Mine stays right around 5000 rpms and between 29 to 32 mph on my data log till the car gets up to speed when i launch at 4500 rpms. The car 60fts in the same area no matter if i launch at 4500 or 6500. And slows very minimally the lower i launch it at. You need wheel speed to get good 60 ft's and to test different air pressures to see what your car likes.
Mine stays right around 5000 rpms and between 29 to 32 mph on my data log till the car gets up to speed when i launch at 4500 rpms. The car 60fts in the same area no matter if i launch at 4500 or 6500. And slows very minimally the lower i launch it at. You need wheel speed to get good 60 ft's and to test different air pressures to see what your car likes.
