Drag Racing Shifting - Racing Forum

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Drag Racing Shifting
Sunday, June 27, 2010 4:22 PM
So I went to the track this weekend and couldn't get below 16.0. I am running the secret intake cam with the HO exhaust cam and HO valve springs, full 2.25 exhaust with header and AEM wai. I tried launching at 3000rpm but just got wheel slip and sometimes wheel hop. I worked my way down to 2000rpm and found that to be the point where I hooked up. At 2000, I wasn't moving very fast at take off and reached the end of all three gears before the finish.

What I am lookin to find out is what everyone is dumping the clutch at and also what shifting methods everyone is using. I have always just done the regular "clutch in" change gears "clutch out" but have been told from some people that I should be double clutching or even "power shifting". I set out to get into the 15's and never got there. It was 95* with tons humidity today, that may have something to do with it.

Any advice would be awesome, thanks.




Re: Drag Racing Shifting
Sunday, June 27, 2010 4:39 PM
High humidity and heat will kill your power. But it really depends on your setup. Are you increasing the pressure in your rear tires and decreasing the pressure in your front tires? Are you roasting the tires off in the water box?

Also, you really don't want to dump the clutch, you should be easing into it quickly, it's really a practice thing, you just have to do it a lot until you get the hang of what it wants.

Do you have poly mounts and control arm bushings? They help with wheel hop quite a lot.

I pulled 15.3's with less mods than you have now, and probably a heavier car last year. I just had a CAI and a cat back. Just clutch in, shift, clutch out as fast as the tranny would let me. I was launching at 3800.







Paying someone to install parts and bragging about it being fast, is like watching someone bang your wife and being proud to raise their kids.
Re: Drag Racing Shifting
Sunday, June 27, 2010 6:03 PM
I usually let off the gas for the 1-2 shift but leave it WOT for the 2-3 and 3-4 shift. I do use the clutch, but its just a floor and sidestep motion. Not saying its the best but it worked for me.



Re: Drag Racing Shifting
Sunday, June 27, 2010 6:04 PM
I've never thought of side stepping off of the clutch, interesting...



Paying someone to install parts and bragging about it being fast, is like watching someone bang your wife and being proud to raise their kids.
Re: Drag Racing Shifting
Sunday, June 27, 2010 8:00 PM
Transporter7220 wrote:

I've never thought of side stepping off of the clutch, interesting...


Well if you really wanna Drag race than Side Stepping the clutch and Power shifting if the only way but i will tell you this PLAN one breaking stuff just incase. the only way your really going to learn your car is practic practic practic try all different rpm range's and see what works best for you/the car. I would say get a pair of slicks if you really wanna race. don't be afraid to brake the car or your not really drag racing are you? I would hope you have a good DD car be4 really pushing your luck with the car just incase.



Re: Drag Racing Shifting
Sunday, June 27, 2010 8:21 PM
i'd be willing to bet that if you run on a cooler day with low humidity, you'll run alot faster.

also, did you air down your front tires at all? that usually helps with some of the traction issues.

side stepping the clutch is either gonna roast the tires or stall the car... as for powershifting, you'll save MAYBE a tenth or two but it's not worth the abuse on the drivetrain IMO...



Re: Drag Racing Shifting
Sunday, June 27, 2010 9:01 PM
launching will ALL depend on the car, track, temp, prep, tires, clutch, power level of car, driver. So asking what someone launches at is like asking what is the best food to eat.

i launch at 4500, on radials at 8psi. I heat them up just to clean them off. assuming you have regular street tires, doing a burnout is a waste and only hurts you. when you heat up street tires, it gets them hot and slick and hard. radials or slicks themselves are made to get hot and sticky. not the case for street tires. so do yourself and everyone following you and go around the water box.

i personally stage when i feel comfortable and leave the line when im ready. i really could care less about the other car if im trying to get the best run i can. he can do whatever but i want my car to launch perfect so i take my time. time doesnt start til i break the beam.

as for shifting, i do no lift shifts and seems to work great for me. drops me right into my power band depending on where i shift. but i have timed my shift light to come on no matter what when its time to shift.

and strat, to counter your .100 or two comment.... would you rather have a 13 second cav or a 12 second cav run a 13.000 or a 12.900 or would you rather race someone dialed in at a 13.000 and they run a 13.200 and you dial a 13.000 and you run a 13.100? tenths win races around here.



Re: Drag Racing Shifting
Monday, June 28, 2010 7:55 AM
I guessing that heat, humidity, and tires were the real issued I was dealing with. I gonna go back on a cooler night and see if can do better. Had the tires down to 19 lbs but the are street tires. Going to also try quickly easing out the clutch and Clyde's method of no lifting and side stepping.

And Justin, this is my dd. Still ran it as hard as I could. It breaks, I upgrade to fix it. Its an excuse to spend money without my wife trying to tell me there are more important things to spend money on.



Re: Drag Racing Shifting
Monday, June 28, 2010 9:19 AM
I would say 19 is too low, I was running 24-25 on all seasons, but like stated above, it depends on a lot of things.

I use that same excuse to upgrade, haha



Paying someone to install parts and bragging about it being fast, is like watching someone bang your wife and being proud to raise their kids.
Re: Drag Racing Shifting
Monday, June 28, 2010 4:32 PM
BuiltNBoosted wrote:


and strat, to counter your .100 or two comment.... would you rather have a 13 second cav or a 12 second cav run a 13.000 or a 12.900 or would you rather race someone dialed in at a 13.000 and they run a 13.200 and you dial a 13.000 and you run a 13.100? tenths win races around here.


and to counter counter, if it means the difference between breaking the car and driving it home, i'll take the loss.

i'm also not a competitive drag racer though. i prefer autox.



Re: Drag Racing Shifting
Monday, June 28, 2010 4:37 PM
what rpm can you rev to? stock 6500? are you tuned at all?

i'll assume no to the above. if so, you arent even close to the redline of the HO exhaust cam. it would be best if you could wrap it out to 7200. however.. on a stock LD9 bottom end i do not recommend this. especially with the stock oiling system but if you dont care, balls to the wall.

either way, LD9's respond really well to staying into the gear until the very last second before the rev limiter hits (even though its not making power). it allows you to be more in the 'meat' so to speak in the powerband into the NEXT gear.

whats the car weigh? whats the elevation of the track?

my guess is with your current setup and 60 degrees and a 2.2-2.1 60 foot your looking at mid to low 15's. since you have koni yellows in the rear set them to FULL STIFF.

you need a tune, an HO intake manifold/56mm tb, and an HO intake cam if you want mid 14's.



180hp in 1989 or 145hp in 2002, you decide. >

Re: Drag Racing Shifting
Monday, June 28, 2010 4:52 PM
I never power shift when I drag race

don't clutch in all the way, just a little beyond the 'engagement point'.. enough that it will let you rip the shifter into the next gear

also, depending on what the car likes, the 1-2 shift if you sidestep the clutch, sometimes bogs the engine down below its powerband. I find if I slip the clutch slightly on the 1-2 shift, I bog less... mods come into play here tho, if your engine is more modded, this may be less of an issue.

launching is a feel thing.. there's too many factors to consider for one concrete way to do it, but the result should always be moving forward rapidly with a little bit of tire chirp and no wheel hop. If they aren't chirping, you aren't using the tires to their fullest potential.. I know it makes no sense (chirping = the tires slipping on the ground slightly) but trust me.. if they are chirping slightly during the initial acceleration, that is as quick as you can accelerate, anything less is slower.

when you reduce air pressure in the front tires you are sacrificing top end for better grip off the line. regular tires aren't slicks, and don't have 'growth' like slicks do.. so try different pressures. everyone has a 'sweet spot' that they prefer, but with regular street tires the window is much smaller.. the lower the psi, the wider they are initially and the less round they are in the top end.

whatever max pressure is on your tire, I'd say start 10psi less and go down from there until you start to really notice a drop off in trap speed, or cannot get the car to launch quicker (60ft times). whatever the PSI before that... well, thats where I'd leave my tires personally.

don't be afraid to check them immediately after a run too, pressure will increase slightly after a run.
also, after you roll through the water box spin the tires up just enough to dry them off (drive around the box if you can). regular street tires actually grip less when heated up excessively.. these aren't slicks...

airing up the rears is also a great idea.. right up to the max air pressure or 5psi more. Don't go too high or you risk blowing them out when you get up to speed.





Re: Drag Racing Shifting
Monday, June 28, 2010 5:06 PM
I never remember how I launch the car. Then again it is different every time i go to the track. track prep is done about as well as they repair potholes in teh Detroit area.

Pardon the @!#$ty KDWS tires that I was using.





Re: Drag Racing Shifting
Tuesday, June 29, 2010 12:08 PM
Thanx guys, I will consider all this my next time out.

PJ- I got to the point where I got just a little chirp on launch at about 2000 rpm and they are street tires. I did hit the water box only because these isn't actually a way to get around it. They spray the lane side to side. Spun them enough to dry and clean them up a bit. Got my best time of the weekend with 19 psi but felt sloppy.

Brad- I know I need the HO intake cam. I have it here just couldn't have my car down any longer than it already was. 2 different a$$hole machinists d!cked me around on modding it for power steering. I have a LO mani in the garage along with the throttle body that came with it, just never got the thing running right when I installed so went back to stock. Will be trying again now that I know more of what I am doing. I DO need a tune already, but I wanted to wait til I got the intake cam done and the konis were full stiff.

Clyde-That looked like my car going down the track.

I really thought the car would do better, but all in all I had a great time at the track. Was there for a local car and bike show called the "Steel Valley Super Nationals". There were a couple j members out there and a bunch of Cobalts among almost 900 other cars registered to hit the track and a lot more just showing. I'll try to get my slips on here later or tomorrow.

Thanx again



Re: Drag Racing Shifting
Tuesday, June 29, 2010 12:13 PM
You might wanna try softening up the damping on your front wheels, 3 out of 4 on my AGX's seem to be the sweet spot.



Paying someone to install parts and bragging about it being fast, is like watching someone bang your wife and being proud to raise their kids.
Re: Drag Racing Shifting
Tuesday, June 29, 2010 5:02 PM
That car was "slow" by most standards today. It needed a lot of tuning. Saddly, I never got around to that before i ditched the S/C.



Re: Drag Racing Shifting
Friday, July 02, 2010 12:02 PM
Back when my car just had a Intake and exhaust and street tires my method was....

Front tires at 30psi, rears at 45psi, rear suspension full stiff, front half stiff

Rev to 2200rpm, drop the clutch, shift at 6000rpm.


Used to run 15.0 all day with that method.






Re: Drag Racing Shifting
Friday, July 02, 2010 3:48 PM
Young J, I too was disappointed with my first times but I'm running an automatic so the launches are a bit easier and less damage when it comes to it shifting.
So going from my first run of a 16.7 to where I finally got it down to a 16.3 with some practice and more track time to learn the car and launching the car.

In the end, my last runs were in the 15.6 range only being held back by a custom muffler shop exhaust which crush bent the elbows to where they were less than 2 inches in diameter which is smaller than stock piping or at least in this case, probably smaller.

Now that I'm running a true 2.5 exhaust from the header back the car's quicker than previously but weight reduction plays a big factor in this too.
So even though you've got the 2.25 exhaust right now with the secret cams, your engine is starving for air, literally.
Get a bigger throttlebody to at least 60mm and get a true 2.5 inch mandrel bent exhaust so that it'll free up the engine to actually breath better.
You'll lose just a bit off of the low end but it'll improve your launches for better 60 foot times which should equate to better et's.

PJ had the best information for getting the car to run it's best and the other thing to consider is to practice.
Your times will come down even though it's hot outside. One thing I can say is that my Cavy always stayed very consistent with times running no slower than 15.8's in the heat to 15.6's when it was cooler and dryer.

Most of all don't worry about your et's just yet but worry about your 60 foot times and how to improve those.
Once you drop another 2 tenths off of your 60 foot times, you'll notice that your et's came down that 2 tenths too and this is how you improve your times when you're starting out.

Good luck and most of all, don't forget why you came to race. It's to have fun so have fun man.




Misnblu.com
Newbie member since 1999
Thank you Dave and JBO!





Re: Drag Racing Shifting
Monday, July 05, 2010 5:52 AM
If you are running street tires just "scrub" the tires if you have to go through the water box and to help remove any gravel or anything debris. By scrub I mean just spin them for a couple of revolutions. As previously stated burnouts on street tires only hurts you.

Try slipping the clutch when you launch. It's hard on your clutch but will yield excellent 60 foot times. Like previously stated, you want your tires to be just chirping, which is indicating you are at the traction limit of the tires.




Re: Drag Racing Shifting
Monday, July 12, 2010 12:33 PM
I have a completly stock 2003 Cavailer that will run consistant 15.8 in the heat and 15.6 when it is cool out.

I run 37lbs of air in the front tires to get just the right about of wheel spin so im not breaking parts.
I launch at 3000rpm
I shift all my gears at 6200rpm.
I am pulling 4th gear between the 1000' and MPH cones.
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