03 BUSA

iTrader: (25)

Seems I get both answers when I do a search so I thought I would just ask the question. Strange DA all the way around 300 springs up front. Do I want the stock springs in the rear? If so with or without isolator. Or keep my hypercoil rear springs in the car?? I have seen some threads that say stiffer is better in the rear of these cars and some that say soft for the rear. What is the right answer???

z28bryan

iTrader: (7)

Good question. I've asked this a few times on other forums. I doubt the answer is going to be full stiff or full soft. I've heard some people say putting the compression a little higher on the right to balance the axle twist making downforce of wheel launching. That was only a thought from a few people.. not sure if that's a bad idea or not. I think the settings you want are going to depend on what your suspension/axle does during your launch. I've heard of people recommending recording on video the launch and playing it in slow motion to see what's going on. You obviously can't see too much from the driver seat.

I race in an event that requires me to launch with 100 treadwear tires on a poor surface and go around an oval track for one lap, so it's an interesting balance that I am trying to tune

UMI Sales

iTrader: (1)

Hello
I just figured that I would suggest seeing how you are using an aftermarket rear end I would go with the stock spring. It will eliminate any clearance issues you may have. And you could go with a 275lb spring in the front to help with weight transfer. You are good with the shocks. But other than that keep the isolators as well to keep the spring from shifting around. Below is a link to show you what front springs UMI Performance has to offer.

http://umiperformance.com/products.php?category_id=93

If you have any other questions feel free to ask and I will be more than glad to help!

Thanks Again
Brad

03 BUSA

iTrader: (25)

I am ok with clearance issues with a 26.5 tire on the rear. Is there anyother down side to using the stiffer rear hypercoil springs??

BMR Suspension

iTrader: (6)

For drag racing, shocks matter more than springs. You are in good shape if you have Strange double adjustables on all 4 corners. You can set the shocks differently each time you go to the dragstrip for different track conditions.

The extension setting on the front shocks is really important. This adjusts how fast your weight transfers from front to rear. Start with a middle setting and loosen 2 clicks each run. Watch your 60 foot times. Keep loosening the settings until your 60 foot times stabilize or you run out of adjustment.

The compression setting on your rear shocks is also important. Start in the middle and stiffen the setting by 2 clicks per run. Keep stiffening as long as your 60 foot times keep improving. Be careful. If the shocks are too stiff, the car will dance around on the top half of the track and you run the risk of losing control of the car. Not good.

I would use hypercoil springs over the stock springs since you already have them.

Z28Bryan is right. Get one of your buddies to video your launches. Save them and study them.

And write down your suspension settings for each run. You'll start to notice trends for what works and what doesn't work.

03 BUSA

iTrader: (25)

Alan, thanks for the great information. That is what I was looking for. The only thing that scared me with the hypercoils is I was told they were the stiffest rear spring available for these cars?? But if that isn't an issue with what I am trying to do then I will just run them. Thanks again.

z28bryan

iTrader: (7)

I've heard many people say use stock springs and I've heard many people say use really stiff springs. I'm sure one choice or the other depends on different other modifications or approaches, but I wouldn't know what those are.

03 BUSA

iTrader: (25)

Looks like I will be keeping the Hypercoils in the rear and just hang onto the factory setup just incase. Thanks guys.