Thread: 1000 lb rear springs for the strip...GOOD OR BAD?

OK, as some of you may or may not know, I have a mission to crack into the 11 second barrier at my local drag strip, something that has never been done before, simply due to the fact that the surface is very poor.

I came close only a few weeks ago, with 2 runs done on the same day, one at 12.092 @ 128.6 mph and the other at 12.091 @ 129.3 mph.

What I did notice on a number of the videos from the day was that the rear end still dropped when launching.

I am currently using a set of K-Sport coilovers, with a 400 lb spring in the rear and the dampers set to hard.

Take a look at these videos and you will see that it is dropping and because of this, unloading the tyres at the front...

YouTube - ‪Dave's N15 003‬‏

YouTube - ‪Dave's N15 010‬‏

As you can imagine, this is killing my 60ft time (and hurting traction through all of 2nd gear).

So here is the question...

I have a set of 1000 lb springs that can be fitted to my coilovers, but am seriously concerned of the car becoming unstable while under braking after the finish line.

Has anyone had any experience in suspension setups in preperation for drag racing and can you offer any advice?

Thanks

Dave

Setting the dampers to hard does nothing for you in the rear. You may want to do that in the front to prevent lift though.

K-sports have little to no compression dampening and the adjuster is just changing rebound with a little cross talk. So by increasing them you are actually making it harder for the rear to un-squat.

Ideally you would want shocks that have tons of low-speed compression (which you can't get in the k-sport body). Since that is directly what you need. You can try and work around that with higher spring rate which seems to be the common layman's way.

EDIT: Looking at video it looks like it unloaded due to a bounce.

Hey, you're right, it does bounce on the 1st video...well spotted!

OK, having taken your advice into consideration, I will try out the 1000 lb springs, but I am concerned that the back end may become unstable under heavy braking.

Are they safe are am I going to virtually have no suspension in the rear?

IMO they are a bad idea.... Your bounce frequency is going to be very high and you don't have shocks that can deal with that. I am a strong proponent of the right adjustment for the problem to get the most out of it.

There are plenty of people who have done it and are still alive tho... So I don't think you will flip over and die from throwing them on.

IMO I'd turn the front up to max and rear down to nothing... make a pass. Then turn the front down to middle and make a pass. See where that gets you.

you should have a long enough run off at the track to not worry about braking. Also i would go with a better slick cause that track is piss poor.

Also try with softer springs for the front wheels

PS I am in love with your car

Is that water he's putting down for your burnout?

See if you can get some VHT Trackbite over there anywere. It's a liquid, and what's typically sprayed onto the drag strips to give grip. When a track is done right, you can't walk across it, without your shoes being pulled off. I buy the stuff by the gallon, and spray it on my tires themselves to let it soak in, in between trips to the track. You could do that, AND pour it onto the ground for your burnout. It's not going to make up for what looks like zero track prep there, but I think it'd make a difference.

Progress recomended 850lbs for rear on a drag set up.

i run 700lb rears. you will need a good strut for the rear and a good front strut spring combo or expect it to bounce worse !

OK, guys this has been a great help!

I will play around with the suspension settings and boost level for the launch and see what happens!

Many thanks!

Dave

P.S. I know the track is poor, hence the poor times, but the next nearest track to me is a good 6 hours drive.