Spring help

[wrogers55]

I'm told my new to me Backdraft 318 has race springs on the rear....and maybe the front as well. I rides like a go cart with very little suspension movement. Anyone know the spring wire diameter of the current "standard" street spring, front and rear. Maybe knowing the race spring numbers as well would help me go in the right direction. Any help appreciated. Thanks, Wayne in Gilroy CA

[Tim Brewer]

Cobras don't have much suspension movement and should be somewhat stiff in order to handle well. You can't tell the spring rate by the diameter of the spring. Get under the car (jacked up) and spin the spring around to check if there is a brand name on it, then look for colored paint marks which will tell you the spring rate per the mfg's code. There really isn't a race or standard spring, just spring rates. Just remember, it's not gonna ride like a family car, it's basically a race car for the street.

[Cashburn]

BDR race springs are generally blue vs. the standard red springs.

[Rwillia4]

Unless you have a hugh understeer or hugh oversteer, you have matching springs front and back.

Originally Posted by Cashburn

BDR race springs are generally blue vs. the standard red springs.

...Errr- I replaced my black standard springs with red race springs

[Cashburn]

Originally Posted by Rwillia4

Unless you have a hugh understeer or hugh oversteer, you have matching springs front and back.





...Errr- I replaced my black standard springs with red race springs

Where in the world did you get black springs?

[Rwillia4]

Well in the front they were located around the strut... lol

$hit I don't know where half of the stuff on the car came from when it was rolled into my garage!!

...they probably came out of some SA Datsun

[tony martin]

FRT SPRINGS

ROAD 11-12MM WIRE
RACE Q3-14MM WIRE

REAR SPRINGS

ROAD 17MM
RACE 19MM


ANYTHING IS POSSIBLE!!!! WOTS A DATSUN???

[jp65cobra]

So if you switch to race springs should you also be changing your shocks to match?

[Rwillia4]

Well some shocks will give you a better feel with some springs and generically work better for performance. But the spring and shocks do not need to be changed together. And there is plenty of different opinions of which springs work best with which springs, this is a personal preference that can only be answered by your driving style.

I like a firm/stiff car that doesn't “flop” around a turn and has a much more aggressive breaking point (when the oversteer or understeer begins) and more difficult to control. Others like to have a softer car where the breaking point is much more gradual and easier to control once you begin to pass that point.
Race springs are going to make the car tighter, roll less.

The combination of race springs and stiff shocks will make the car more precise and have a quicker response to any driver input. The negative side is the cars ride is stiffer.
There is another component that can vary the handling dramatically: sway bars or roll bars. These need to be changed out in pairs (front and back) the bigger the bar the stiffer the suspension. What they do is mechanically connect the left side with the right side. So that if the left wheel goes up the right wheel. The distance the right wheel will come up is dependent on the size (diameter) of the bar. The bigger the bar the more the left and right will come up the same distance and the tighter the car. The flatter the road the bigger roll bar you can use. You will increase your capabilities, but there are some downsides in ultimate controllability.

Example: If your car is stiffer the result would be similar to running to a cliff edge as fast as you could trying to turn at the last second, you accidently wait too long and falling off the edge you would try to regain control all the way down, which is difficult as you fall down. A softer sprung car would be similar to running across a mound and go over the top while trying to turn you miss the top but you can still turn and return toward the top. You get the edge fast with a stiffer car but if you push it past the edge it is more difficult to handle.

What is the best combination? Like I said before it depends on your driving style. A web search on “oversteer vs understeer” will give you some ideas on how to adjust your suspension to match your needs and capabilities.

Rob

[eschaider]

Originally Posted by wrogers55

I'm told my new to me Backdraft 318 has race springs on the rear....and maybe the front as well. I rides like a go cart with very little suspension movement. Anyone know the spring wire diameter of the current "standard" street spring, front and rear. Maybe knowing the race spring numbers as well would help me go in the right direction. Any help appreciated. Thanks, Wayne in Gilroy CA

Wayne,

This might help determining how zesty your springs are. Click here => http://www.jblmotor.com/spring.htm.

If you want to get together and tell lies PM me we can't live but a couple miles apart.

Ed

[RICK LAKE]

wrogers55 Wayne did you ask or tell the guys at Backdraft what you where going to do with the car? I am sure like ERA they setup the car for the middle of driving between total street and total roadracing. The easiest thing I can tell you is to get the street setup of springs and shocks, and then after you have some time with the car, you can swap them over to a race setup for better handling. Other safety equipment will be needed when you get the bug for going fast. Shocks come in different lengths and have single and multiable settings for rebound and compression. Springs come in all lengths and spring rates. Most are messured in how much weight is needed to collapes the spring 1" This gives spring rate numbers, the lower the softer the ride. You will also need to know length for height of the car ride. Have BDR do the alignment and weight and balance the car in the 4 corners. Tell them your real weight so they can setup the car correctly with you driving it alone. This will be a good starting point for you and your new friend. Rick L.

[cbreez]

It seems Rob tries to sound intelligent here regarding springs and shocks...
but he needs to google a few more "handling" sites...BTW, the word is "huge"...

Unless you are really "racing" your car much, or are extremely overweight, the stock springs and shocks with some ride height adjustments will serve you just fine...

I am sure T. Martin has selected the correct springs on these car for 99% of the buyers...

[cbreez]

A quicker and easier adjustment to "soften" your car up would be tire pressures.
A Backdraft replica has very little area for tire clearance. A softer spring will cause a "tire rub" issue. Ride heights are critical. The nature of this car.

[Rwillia4]

cbreez I always forget how smart you are... good job with some constructive input.

[cbreez]

My input is always constructive. Thanks!

[Doug I]

Originally Posted by Rwillia4

cbreez I always forget how smart you are... good job with some constructive input.

I'd forgotten how nice his car is too.

[Blittleton]

Originally Posted by wrogers55

I'm told my new to me Backdraft 318 has race springs on the rear....and maybe the front as well. I rides like a go cart with very little suspension movement. Anyone know the spring wire diameter of the current "standard" street spring, front and rear. Maybe knowing the race spring numbers as well would help me go in the right direction. Any help appreciated. Thanks, Wayne in Gilroy CA

Wayne,

We never changed the front springs. They are the originals that came with the car. Mike change the rear due to bottoming out.

Bill