improving 1/4 mile times

[Nathsx]

Hi guys basically ive been to the drag strip at crail a few times now, if anyone knows it the surface is horrendous.

Anyway long story short I want to improve times, the best 0-60ft was a 2.3 on goodyear eagle f1 225/40/18. 103 mph terminal on 1/4

I dont particularly want to be changing much on the car as its a daily. Having said that it seems to suffer from alot of axle tramp on launches obviously id expect a bit but is there anything else I can do to reduce this effect.

I know I could get more power or drag radials etc but I want to fine tune this setup on my s14a.

Running approx 300bhp on avcr boost control. Ive changed it off automatic to manual to improve the spool,this also means I can limit the boost in first and second fortunely.

Suspension wise it has apex gen 2s fast road, adjustable toe and camber arms standard traction. Standard diff and driftworks subframe bushes.

Obvious thing is to reduce rear damping but is there such a thing as too soft?

Does the 200sx suffer from any other inherant issues other than the standard bush play which is never good.

Any suggestions welcome

[piman2k]

You could buy my R888's!

[s13silvia]

I'm no dragger, but id suggest keep things simple and look to old american drag racing tips n tricks.
welded/2way diff, light flywheel+strong clutch, grippy wide rear tyres and some weight loss should see a marked improvement

[FireStorm]

Soft rear suspension.

Often ppl find putting a bag of cement helps with traction in the boot

[zeppelin101]

Axle tramp has gotten worse in both 200s I've owned with lower ride height and stiffer springs.

I reckon the best thing you could do is stick some standard rear suspension on tbh. Or something along those lines anyway.

[AdamRPS13]

What were the times you've ran?

Put a little bit of pre load on the transmission system by holding the revs around 3k and letting the clutch up till its slightly biting with the handbrake on, and when the lights go drop the handbrake and clutch up, foot down. That might help a bit with axle tramp.

2.3 60ft is not terrible either, although i expected a higher terminal speed than 103mph with 300bhp!

I used to do the 1/4 mile a lot in my old FWD astra sri turbo, and i was running 290bhp and getting 2.2 60ft and 106mph terminal running a 13.5 1/4 mile.

[sideways14a]

A terminal of 103 with 300bhp is rather low, i would be expecting 110.

[Actual_Ben_Taylor]

Uprated subframe/diff bushes will help a lot with the axle tramp.

[Johnny]

wide rear tyres

that might not help ..... with the same weight and rolling diameter all you are doing is widening the contact patch and making it shorter .... this is good for grip when cornering, but you have less contact for accelerating and braking

[800bhp]

18" wheels, low profile tyres with stiff sidewalls won't help ..... you'd be better off with standard 16" wheels/tyres and run about 16psi

[Mike41288]

I run similar power in mine and I was getting 14.4 1/4's, found out the below average time was due to a standard clutch and harder than standard rear suspension!
I run mine as a daily and as I'll only be on the strip 3 times a year, I don't want to start messing about with alignment/silly power/no interior I'm just gonna get some bits that I can swap over the night before on the ramp at work:

R33 4.1:1 diff (got shafts)
2x 255/50R16 Mickey Thompson ET Street Radial on LMGT4s for the rear
Standard rear suspension
Was also thinking of utilising the Launch Control function on my RLTC when it's finally set up, but will see how it goes without it as it's sort of cheating

I'm aiming for low 13s, maybe even high 12s on a good day.

[AUTO1]

What you need, is my home made launch/RPM control.
Knocked a second of my ¼ time.

You get about a meter of weakish string tie it to fixed part of the car ,then tie the other end in a noose to the throttle arm with engine running set it so it stops the throttle opening more than say 3000 rpm then you are set.

On the line you open the throttle to the restricted point drop the clutch at the light in first gear.

This get you off the line in a controlled manner with out to much strain on your drive train and excessive wheel spin.
As soon as you are moving just stamp down on the throttle and break the string and off you go.

[Nathsx]

A terminal of 103 with 300bhp is rather low, i would be expecting 110.

used to get a terminal of 109 on old turbo which was ****ed running 1.4bar on standard injectors at maxed duty.. not clever but it worked..

now on refurbed t28 and nismo 555's running 1.25 bar

does a 14.226 on this current setup @ 101.6 mph with a 2.3 0-60 ft with a passenger, has stripped interior but rear half cage, weights 1270kg no driver.

i want into the 13's!!

I run similar power in mine and I was getting 14.4 1/4's, found out the below average time was due to a standard clutch and harder than standard rear suspension!
I run mine as a daily and as I'll only be on the strip 3 times a year, I don't want to start messing about with alignment/silly power/no interior I'm just gonna get some bits that I can swap over the night before on the ramp at work:

R33 4.1:1 diff (got shafts)
2x 255/50R16 Mickey Thompson ET Street Radial on LMGT4s for the rear
Standard rear suspension
Was also thinking of utilising the Launch Control function on my RLTC when it's finally set up, but will see how it goes without it as it's sort of cheating

I'm aiming for low 13s, maybe even high 12s on a good day.

did consider the 4.1 ratio might look into changing this and diff bushes!

might need to get the car dynod again, did run 320 bhp on the last dyno and setup not current but i think that dyno over read alot..

that launch control is hilarious but prob works a beast :P

[sideways14a]

I consistently did low 13s with a best of 13.1 at 109mph with my s14 running 300bhp and 350 ft.
That was without launch control running.

[AdamRPS13]

I consistently did low 13s with a best of 13.1 at 109mph with my s14 running 300bhp and 350 ft.
That was without launch control running.

This is the time i'd be expecting to run with 300bhp s-body considering i reckon i could have ran around that with better tyres in my old FWD astra lol.

[sideways14a]

Yeah low 13s on stage 2 should be what you expect if your doing 14s with ~100mph terminals then your car aint got the power it should have, if your doing 14s with a decent terminal then your loosing it on the launch.

Terminal speed is a good indication of the outright acceleration of the car regardless of traction off the line.

[shogun]

*You might want to go a little bit lower on the air pressure.
*One thing you may want to play around with is, what rpm to bring it out at and when to shift.
*Have someone watch how your car reacts and just play around with the different shifts until you find what your best time was.
*Practice launch from 2500rpm and up and shift points from 6500rpm and up.
*Find an abandoned or secluded place and practice launching the car.

A copy/paste from another thread about launching....

I'm not sure what to launch at with your car, depends on your power, where peak torque and hp occur, and what kind of tires you're running. Every car is different, and each car can be different on each different day, even at the same track.

Generally speaking, it's a very fine/delicate balance. With my car, I'll bring the revs up nice and steady, wait until I have them perfectly steady, on a warm day, say at 5500 rpm. I'll slowly let the clutch out, right on the brink of grabbing, the tach will dip- that's the grab point.

I'll modulate the clutch to where I can keep the revs steady again at 5500 rpm and wait for the green. Generally when the green hits, the gas pedal goes down- quickly, fast, but also gradual/fluidly. No slamming the gas down, no stabs of the pedal. Only smooth motions, no herky-jerky crap.

As the gas pedal goes down, you gotta use your left foot to regulate the power going to the wheels. Again, all motions must be fast and fluid and smooth, but also very quick <-- that's the key.

You gotta learn the feel of what it feels like just before your car is gonna break traction, and learn to kiss that edge without going over it, but to accomplish that you gotta push the envelope to learn and know where that edge is (and know that edge changes on each run, slightly).

As it hooks, you gotta "feel" the clutch pedal, you'll know when to let it out all the way, if you can. Some times, I barely get the clutch pedal all the way out before it has to go down again for the shift to 2nd gear.

You gotta do this time and time again, over and over again, to learn your car's nuances. Here's where it gets tricky- you can complete a run, cut a 1.85 60' time, come back study your notes, take 1 psi out of each rear tire and do the same thing but be able to launch higher and all of a sudden, BOOM, 1.72 60' time on the next run and shave 3 tenths off your 1/4 mile ET as a result, given you don't mess up your shifts as you go down the track.

Was it the 1 psi less in the rear tires? Was it being able to launch at 100 rpms higher at launch? Did you shift too early on the previous runs? Or did it all simply come together on that run?

The other key is consistency. The more consistent you can get with your runs, the better the results on the next run. Cuz you can begin to play detective and find the little things you need to tweak/correct on the next run to make it better, etc.

It takes tons of practice. I have almost 17 yrs of practice now, and I'm no master of the technique- I'm a good drag racer, sure, but I ain't "great" <-- And that's not me being humble, that's me being totally honest and knowing my place, cuz I've seen and I know several really great drag racers who make chumps outta guys like me.

It's part science, part art, and lots of concentration, hard work, dedication, perspiration, determination, patience, and practice-- if you find those things fun, you'll "get it" eventually.

If you're just starting out drag racing, you'll make mistakes, don't waste a run, if you blow the launch, haul ass down the track and work on your shift points from gear to gear, etc. Take notes on everything, launch rpms, shift rpms, tire psi, front and back, try to weigh your car, if you can, get out your dyno sheet and study shift points, and adapt at the track when your calculation prove to be close but not quite right, etc...

Most people discount drag racing as not requiring a whole lot of skill- the people who feel that way are the ones who have either never tried it, or have and aren't that good at it, and aren't willing to work at it, to become better at it, etc. It's a world of nuances and subtleties, and a couple hundred factors to consider that are often beyond your control.

And it can be frustrating at times, you can do everything right and get crappy results- it just takes some severe stubborness and stick-to-it-iveness.

And many people don't care about the nuances needed to get the absolute best times out of their car, even guys who have drag raced quite a bit- not everyone is going to be a student of the game and study hard, absorb all the info around them to excel at it, etc.

Some people have the attitude of "Eh, it's only drag racing"- those people are usually not the ones who are very good at it... "

End...

have fun - good luck