Drag racing suspension setup / weight / tyre pressure - EXTENDED TOPIC!

[RO_SUNNY]

Hello everyone.

I have seen some of my pictures and realised that I can go lower than 11.67 (which was my best run) on the 1/4 mile by just stiffening my rear shock absorbers and by inflating the tyres more ( when I did that 11.67 the tyre pressure was 2 bar)

Check out my pictures also ....my opinion is the car is to tilted on the back when I am racing

Also we can discuss about weight saving : cut the doors interior, change the glass windows for plastic ones, take out al unecessary weight from the car.

Waiting for sugestions from your side!

Cheers,
B

 

[johnsy]

How accurate is the timing gear and distance over there? is it governed

you may want to raise the rear of the car and like you ve stated use the hardest damper settings if you want to try eliminate the squatting,

as for weight just go mental remove everything drill holes in everthing, as for tyre pressure's im sure fastguy use's 20psi

 

[RO_SUNNY]

How accurate is the timing gear and distance over there? is it governed

I am not sure if I totally undertood what you were trying to say .....but they use a PORT-A-TREE system which is a professional timing system.
Port-a-Tree systems are used by alot of drag strips in the USA

 

[chopper]

As for weight you need to be ruthless and be perpared to do something to achieve this. What i mean is you need to remove every thing which is not needed for that trip down the straight. I see you have the passanger seat still in there. thats a few KG's saved for the sake of a few bolts. Yes you would have to stay another hour or so after you've finished putting it back together before you left but you might get the results you want. Or take it on a trailer.

As for the suspension, i know on RWD cars they tell you to soften the rear. So the weight is transferred on to the rear wheels for more grip and i would assume it was the other way for FWD. So if you know how the power spead is over the 4 wheels start from there. I dont know what the ratio is on a pulsar. My old calibra was 70% front 30% rear. You could then adjust the shocks to the given ratio and hopefully find a happy medium.

 

[williams]

you tend to get a little wheel spin from the front when it lifts so i would lower front, highten rear and stiffen rear dampers. i think what dan means is it a true 1/4 mile over there? ive heard a few times that alot of drag strips abroad are a bit shorter? thats why alot of foreign cars seem to have faster times?

 

[johnsy]

and the strip in newzealand is downhill lol, basically how accurate is it. i think it t.s.i certified over here or summit like that,

 

[PobodY]

If you're not cornering at all, can you remove the anti-roll bars? I don't know if this really helps, but I think DP Jnr was quite keen on this and he had really good times off the line.

 

[RO_SUNNY]

Remove the anti-roll bars?

Hmmmmmm....wil try to do that inflate my tyres until 2,5 bar and also stiffen my rear dampers.

Regards,

B

 

[iomegalinux]

whiteline sway bar has a setting for maximum traction.also remove any toe-in/out, front and rear ... you can also use the KCA349 to align subframe for maximum traction
http://www.whiteline.com.au/product_detail.php?part_number=KCA349

 

[campbellju]

Remove the anti-roll bars?

Hmmmmmm....wil try to do that inflate my tyres until 2,5 bar and also stiffen my rear dampers.

I'm no drag queen but that strategy sounds wrong.

By all means stiffen your rear dampers but you'll mainly affect the re-bound not the compression. Stiffening the front will reduce the lift but the pro fwd and 4wd drag racers just seem to stiffen everything up to minimise movement. Your tyre's sidewalls are then the key suspension component. Run softer tyres pressures to increase the tyre contact patch under weight but also to slow the rate of weight transfer.

A few simple steps:

keep practicing
run lower tyre pressures (1.7bar as a starting point, 26 psi? Difficult to say anything useful without knowing your tyres.)
Full stiff on your dampers, lower your car as much as possible all round with your front slightly lower rather than higher than the back.
Leave your ARB's on as they help to balance your car's grip side to side.
Strip out as much of your interior as you can

Jim

 

[skiddusmarkus]

That rear squat is giving your gearbox an easier time, allowing the fronts to spin a little when you launch.If you let a bit of air out of the tyres it lets them flex and get better traction but don't go mad as its not a good idea to be doing 120mph with underinflated tyres.

 

[RO_SUNNY]

Thank you very much Jim.

Will try and do that .....but for the time being I have a massive crack in the exhaust manifold that I need to fix

 

[campbellju]

It's always the way.

Looking back at your OP, the angle of attack of your car won't be changed significantly by playing with the dampers as they affect the rate of movement rather than the amount of movement. Equally fitting super stiff springs won't change the fact that you're launching and physics will shift weight to the back. Lowering the mass will reduce the amount of weight transfered but you've got to look out for rubbing issues.

 

[skiddusmarkus]

The dampers do affect it in my experience campbell, when I went from stock suspension to konis the rear didn't squat half as much so the fronts span less.It could have been down to knackered old struts though.I couldn't say 100%.