Should I be satisfied with my times?

Ok if its dumb question time I would like to add a question I have wondered.. Don't haze me too bad but what EXACTLY is double clutching and is it something that should be done at the track? It seems to be just like it sounds, clutch, shift to neutral, clutch, shift to next gear. What exactly does it do (if anything)?

1st, to txredgt: Yeah, you got it right. Only required on transmissions without synchros, i.e. no street car built in the last 30 years. You might have to do this on a trashed tranny that has suffered way too much abuse just to get home, but I wouldn't bet on it ever being practical knowledge. Might come up on farm or some industrial/commercial equipment.

To the OP:

Your times are fine for your power. Your tire's rubber might have degraded a bit from age. 1/4 mile times are so weather-dependent it's silly. Not to mention the lower the elevation the faster your car will run. And some tracks are known for abnormally fast times, like Englishtown. You cannot really compare times to other people as if you all ran on the same day on the same track. Lots of people forget this.

You have really no power mods, so your trap speed is in line with expectations. If you haven't been to a track before, you did really well for the first time. Your next trip will probably show a few tenths drop in ET, and maybe pick up 1/2 mph or so.

And DROP THE TIRE PRESSURE! Street tires are designed to resist losing traction as heat builds up, and to resist heat build-up. But you will likely see a better 60' and a resultant drop in ET if you go down to ~24 psi or so. Make a run at 30 psi, drop to 25 psi, and make a decision about which felt better and gave a better timeslip. If 25 psi was better, try 20 psi. Go to 2 if it was better, 27 if it was worse. You need to find the pressure your tires like for your car and power level by experimenting.

Just remember to run closer to 34 psi on the street. A 1/4 mile blast is one thing, running your tire half-inflated on the freeway will overheat your tire.

Slipping the clutch is lifting off the clutch while pushing on the gas. You start off like normal but keep pushing the gas to the floor as you lift off. The thing is to make it smooth with as little tire slip as possible. Realistically, you need to practice on the street to get good at it. The track should be stickier but the feel you develop in practice will let you recognize this and adjust quickly. On normal street tires you need a little tire spin to keep the engine rpms up, but a sticky tire will allow you to be out of the clutch quicker with more gas. And by "a little tire spin" I mean not enough to really leave marks, just enough to make a noise. The first foot or so might leave a black mark, but that's it.

03_TrueBlue_GT said:

Well heck I might just let y'all drive my car to get it in the 13's.

Again thanks for the pointers guys. At least I feel better knowing my car should run faster than stock.

Also we are at sea level out here in Houston Tx so altitude isn't that big a factor.

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If my overweight self can run 11s in my near stock 2011, I know you can go 13s in your GT Seat time will help out and it can be tricky on street tires.

I'm a driver for hire

03_TrueBlue_GT said:

Well heck I might just let y'all drive my car to get it in the 13's.

Again thanks for the pointers guys. At least I feel better knowing my car should run faster than stock.

Also we are at sea level out here in Houston Tx so altitude isn't that big a factor.

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I'll 2nd that. I'll put it in the 13's this summer, and run faster that D98GT. But that is nothing new.

Slipping the clutch is a bit easier to explain how to do correctly than I have seen so far in this thread. Hard to do, easy to explain.

Each car should be launched at a high enough RPM to put the engine in its power band immediately after the launch. We are lucky, we are V8s w/ good torque early on so we don't need to launch at +4K RPM or anything crazy.

Next time you are at the track:


As everyone has mentioned, vary the amount of throttle and clutch pressure to get this done. It eats up the clutch, but it is a much faster method of launching if you are willing to go up to as high as 3K RPM. How high you can go is really only limited by how rough you are willing to be on your clutch. However, lack of traction can make effectively launching at high RPM very hard on the clutch, which is why we don't just look at our dyno's for our cars and pick a launch RPM that is nicely into the powerband. There is a compromise, if the track is not well prepped and has poor traction, then a compromise is in order.

When I still ran 245s in the back my best RPMs for launch were 2400, but there was almost no track prep. Now, w/ 315s, it is more like 2700 RPM.

2000 is a rather a bit low to be maximally helpful, IMO. Practice keeping the tach at your chosen RPM during the whole launch phase and when your pretty good at that it'll be helpful for you to experiment w/ different launch RPMs and see how they work out for ya.

BTW: I got better 60' times in my car with ~22psi than with >30PSI and I use Nitto 555 street tires (not the DRs) as well.

Also, the weather's affect is best shown in your speed at the end of the course. If you didn't miss shifts, bog badly at the start, etc - you can get a good read on conditions based on your trap speed at the end of the run.

At 98.3 MPH, that was not a good day. lol Part of a bad trap speed could be not launching at a high enough RPM to put the engine in its power band immediately after completing your launch. So that could be part of your 98.3, as well.

I didn't have gears, and had nothing but a K&N filter, but I got my car into the 13's when I still had 245 tires in back (see sig). However, that was at my track, and as the >100MPH trap time in my sig shows, the conditions were rather good that day.

A few months ago, I went out to the track and had trap speeds around 101.5 MPH. I got to 14.0X before the weather even had a chance to really cool down that day. However I was out of practice launching, so my 60' on the 14.03 second run was horrible at 2.25 seconds. Then I had to leave early and never got the chance to do better. Too bad, 13's were in the air for later that night if my schedule would have let me stick around.

Have fun, you will find a day w/ good conditions (and so >100 MPH trap speeds) and will get into the 13s if you've practiced enough by then.

You should be able to nail down 1.9's on stock tires with practice and decent track prep. Anything in the 2.1's, and you need to practice more. This is my slipping the clutch. I've gone low 1.9's on street tires and 240-264rwhp in my mustangs. Here, I was above that in my vette with headers and drag radials(high 1.6 60ft). Still had to slip the clutch(IRS). Got out of 4th gear when I missed because of issues with 4th gear. I've got more launching videos, but have even more I can post of better drivers slipping the clutch.

YouTube - ‪z06 vs Evo‬‏

What works for somebody, does not always work for somebody else. One of my old buddies(JBVobra on stangnet), went 13.33 in a bone stock 2001 mustang Bullitt. He also posted some of the most impressive stock C5Z and C6Z times years later. Practice launching the car on contrete streets with no traffic, just 0-30mph. Don't get nervous at the the track. Good luck!

Some people don't believe me, but I cut consistent 1.89 60ft times on stock 245/45/17 street tires. Only suspension mod was having the sway bar unhooked. We don't have 1/4 tracks around here, only 1000ft tracks. But I went 10.99 at 93mph in my 99gt with only an o/r H pipe, magnaflows, and 3.73's. I launched my car At 3500rpm and slipped the clutch enough that when I fully disengaged the clutch, it was at 3500rpm. Just practice man, and don't get discouraged.

We only have 1/8 mile tracks here. What would be a good 1/8 mile time if I could pull off a 1.9 60ft? My car is a 2002 GT full weight, 255/45/17 Nitto 555's, 373, Bama 93 octane race tune, Flowmasters.