After a rather embarrassing first time out at the track, I've got some questions about how to launch an NA at the strip.

Time-

.724 RT
2.748 60'
11.637 1/8 ET
63.02 1/8 MPH
17.583 1/4 ET
80.51 1/4 MPH

These numbers are disgusting even for stock. I must be completely off on my launching technique. I'm running an aluminum flywheel.

How do you NAs launch? What rpm/technique? What difference does the flywheel make? All input is appreciated.

 

i think slipping it out work the best as for as stock goes( I have no experience otherwise)..letting the clutch drop just bogs the car down w/ or w/out tire spin...Rotary's just have no power down low so anytime the RPM's get below 3k it just bogs!!

 

as far as the 1/4 mile time goes that's pretty bad since my once apon a time Automatic ran a 17.3!!

 

Ive heard that a 6-7K dump works the best on a stock car. Cant really prove it though. I use to slip it around 5500rpm and get some 2.2 60' with all season tires, but I heard slipping the clutch really shortens the clutch life.

 

Flywheel makes a very large difference.....not ALL in the launch though. The flywheel will make it a LITTLE shittier in the launch and it will make shifting to second a little shittier and it will make shifting in to third a little shittier.

I have a light flywheel and I have found that holding the revs at 4k and accelerating IN to the launch gets me my best take off. You have to shift incredibly fast in second and third so as not to lose any of that inertial momentum of a light flywheel. I can typically barely chirp second and when I get to third I get a little push if I hit it just right and quick enough.

Are you getting much wheel hop? Or are you spinning them through 1st? I have 17 inch rims with 215/45s for tires and I lower my rear wheel psi to around 18-20. You will notice a HUGE difference in your launch.

The only other advice that I would give you is to make sure that everything is working right on your car and give her a FULL tune up before heading to the track. Change that oil every 1000 miles or less and she will be good to ya.

Hope that helps,
Lee

PS- My last track run I got 15.38 with mods listed. When I get sick of my interior I will strip it out and should be running real low 14s if not high 13s. Weight reduction = good.

 

Get a set of kumho mx tires and do 7k slips. You should beable to cut that 60ft down to 2.0 on those tires. Thats about 1.5 seconds off your final time. 16.0 still isnt great though- what elevation is your track at?

 

I don't think stripping the interior in hopes of dropping 1 to 1.5 seconds is very realistic, but good luck anyways.

If you go by the general equation of 100 lbs. is .1 second, you will need to drop 1000 to 1500 lbs. to lower your times that much.

fikshun

 

nm- reading comprehension > me

 

capn wankel mentioned it... last line in his post

 

In my only race ive ever done, is drop the cluthc at 3200 rpm, but i spun the wheels all the way through 1st.

Any tips?

 

Get better tires.

 

Well, unfortunately I must admit here that my car is not very stock. It's a streetported Series Four. The exhaust is a straight-pipe back to the mufflers. It's got a K&N on it, removed rat's nest, removed almost everything, ported TB, and wired open six ports. I experienced a bit of wheel hop. I'm hoping my problem is mainly the speed I let the clutch out at. This car is difficult to launch correctly. Sometimes I feel like it launches different every time. Perhaps what I need is just some more time behind the wheel. I'm going to check my tire pressure as well. The tires aren't anything great but they were about $80/piece Z-rated rubber. Thanks for all the input so far.

 

Umm your streetport with the mods listed should get you mid-high 14s...

I have a buddy that runs low 14s with a 2100 lb FC stock ported with just a header/straight through exhaust and k&N filter with 330,000 miles on the block...........I on the other hand have everything that he has done without the weight reduction......and I am a good driver. I have heard the .1 second per 100 lbs before but......I dunno what to tell ya. He gets his hands on slicks and he has a 13 second NA stock ported.

-Lee

 

get rid of the aluminum flywheel. Use a heavier flywheel and pressure plate. This will allow you to launch it at lower RPM without the engine bogging. If your using street tires, drop your tire pressure to 15psi for better traction.

 

i always got the best launch just hammering the clutch at just more than 3k, just be ready to start shifting, because if you hit it just right, the car will hook up without too much slip, and just take off.

Unfortunately, the track tends to be a little slicker, so you have to slip a little more. Just feel around for it though, you got to find the rpm where your car doesn't hop, and doesn't bog at the same time. There's no shame in getting a little spin if you are still winning

BTW i ran 16.6 on a car with everything in, it including subs, and only with an intake

 

What kind of track do you go to? Most drag strips are alot stickier than the street.

 

that spins the wheels something fierce....at least with my car it did.

 

I dont know how to launch very well at all but slipped the clutch at 5k and got a lot of wheel spin and hop. I know I need more practice but should I go to lower rpms while launching?

Also how much does lowering the psi to 15-20 affect everyday drivability?

 

ive never raced on a track in my life
but when i race i rev it up to like 3.5-4 grand and dump the clutch and floor the gas
thats with no lsd
bone stock s4
ive never been taken off the line
i havent raced that much
but it hasnt happened yet
but i messed up my diff so im getting an lsd put in right now and i get it back tomorrow

 

Do not drive like this all the time. You will damage your sidewalls and that damage can lead to destroying your tire (possibly a blowout on the freeway). Lowering tire pressure that much is only for track use.

 

To help your reaction time (I know you posted about RPMs, but...) I will tell you something my pops told me a long time ago. When you stage, don't look directly at the lights. Look down the track at the finish line and watch the lights out of your periphrial vision. Humans react to motion in there periphrial vision a lot faster then if its in your direct line of sight, especially at night since human sight is based on motion and is attracted to light. He taught me this when I we went to Englishtown NJ to the NHRA summer nationals. They had a reaction time machine where you sat side by side and held the steering wheel. The tree was out front and you held the red button (simulating a brake line lock) to set the stage light. When the tree lit up, you had to hit the gas. My R/T was terrible because I was looking at the light. He told me to look straight ahead and don't focus on the light and it worked a lot better.

The very best thing to help R/T is consistency. Stage in the same place, launch at the same RPMs and work the pedals the exact same way each and every time. And don't wait until you see green. If you are still sitting still when you see green, its too late. .724 isn't too bad for your first outing so I don't think you are waiting too long, but these are things you will want to keep in the back of your mind. Have fun and don't be discouraged. You will only get better.

 

.1 second/100lbs is just as intelligent as 15% drivetrain loss....

 

you are absolutely right, well said.

 

Thanks for the info. Very informative and good to know.

 

i had an 1987 na with headers,hksmegaflow,& exhaust that ran 14.80@95.50mph i used to do 5k and drop the clutch