BSP Question (springs) - local derivative of SCCA
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From: Ypsilanti, MI
BSP Question (springs) - local derivative of SCCA
I've read a bunch regarding spring rates, etc. It seems that most people recommend something like 600f 500r spring rates for AutoX use. However, I can't seem to find springs for a 350Z that are anywhere close to that...
I'm unclear whether "coilovers" are allowed, so I was looking for a separate spring/shock combo. I know that the front suspension is pretty much a coilover anyway, but it's confusing.
Here's the relevant text from our local ruleset for (T)BSP:
It looks like coilovers, because they allow ride height adjustment by altering the lower spring perch, are disallowed by this.
Here's SCCA's BSP text:
It sounds like this allows coilovers (in the front, anyway)...
So... does anyone know where I can find individual springs that fit the 350Z that get the spring rate higher than +10%? What about a place to order the spring/shock set from a NISMO 350Z (not the S-Tune shocks/springs, but stock springs/shocks from the NISMO Z)?
I'm unclear whether "coilovers" are allowed, so I was looking for a separate spring/shock combo. I know that the front suspension is pretty much a coilover anyway, but it's confusing.
Here's the relevant text from our local ruleset for (T)BSP:
Suspension springs may be changed provided they are the same type as original (coil, leaf, torsion bar, etc.) and use the original attachment points. Ride height may be altered only by modifying the springs, by using lowering blocks between the springs and the spring locator on the body, by using lowering blocks between the leaf springs and the original attachment points to the axle, or by conventional wheel alignment. Spacers or lowering blocks may be adjustable.
Here's SCCA's BSP text:
Ride height may only be altered by suspension adjustments, the use
of spacing blocks, leaf spring shackles, torsion bar levers, or change
or modification of springs or coil spring perches. This does not allow
the use of spacers which alter suspension geometry, such as those
between the hub carrier and lower suspension arm. Springs must be
of the same type as the original (coil, leaf, torsion bar, etc.) and except
as noted herein, must use the original spring attachment points.
This permits multiple springs, as long as they use the original mount
locations. Coil spring perches originally attached to struts or shock
absorber bodies may be changed or altered, and their position may
be adjustable. Spacers are allowed above or below the spring.
of spacing blocks, leaf spring shackles, torsion bar levers, or change
or modification of springs or coil spring perches. This does not allow
the use of spacers which alter suspension geometry, such as those
between the hub carrier and lower suspension arm. Springs must be
of the same type as the original (coil, leaf, torsion bar, etc.) and except
as noted herein, must use the original spring attachment points.
This permits multiple springs, as long as they use the original mount
locations. Coil spring perches originally attached to struts or shock
absorber bodies may be changed or altered, and their position may
be adjustable. Spacers are allowed above or below the spring.
So... does anyone know where I can find individual springs that fit the 350Z that get the spring rate higher than +10%? What about a place to order the spring/shock set from a NISMO 350Z (not the S-Tune shocks/springs, but stock springs/shocks from the NISMO Z)?
As you mention, the front of the Z is a spring over a shock or a coilover.
No coilover for the rear. Doing so would alter suspension geometry. OEM Spring and shock perches must remain the same.
And the S-Tune suspension above would NOT suit your needs? Why?
No coilover for the rear. Doing so would alter suspension geometry. OEM Spring and shock perches must remain the same.
And the S-Tune suspension above would NOT suit your needs? Why?
Those (your suggested rates) seem pretty aggressive for a stock valved stock (10 and 8.5 kg where stock are 6-7 kg depending on year). Not sure how long they would hold up and if they would work well at higher speeds. Let's see what the other autocrossers like.
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From: Ypsilanti, MI
(I know the following will likely make me lose credibility, but... FWIW)
In real life, I've got an 07 w/ 275s all around, Nitto NT05.
I set up in Forza 3 an analogue:
245s all around, best non-slick tire.
Cams to get 315 hp
set up adjustable suspension to have OEM camber, spring rate and ride height. I estimated the shock valving at about 3.5
Set up adjustable final gear to 3.3 (auto)
Test track:
Iberian - Mini course (roughly 34-38 seconds for stockish cars)
I saw a delta of at least 2 seconds with springs/shocks alone. That's beating my time for a same-compound tire Acura NSX (otherwise stock) on the same course.
Theoretically, that would be enough to be viable for trophying the local street-tire version of BSP with good driving.
Last edited by scardeal; Nov 1, 2010 at 12:57 PM.
I use DA Koni's on my BSP car, but with soft springs at the moment. Plan is to go to a 14k front 12k rear next year. I don't believe you need to retain the factory spring bucket in the rear.....not positive though. Betamotorsports would know for sure I'd imagine....may want to PM him.
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From: Ypsilanti, MI
Is this incorrect?
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On the street you get a relatively comfortable ride. Push the Z in the corners (autocross) and the spring rate increases considerably.
Last edited by davidv; Nov 1, 2010 at 02:33 PM.
No mention of what kind of LSD. IMHO (and I put my money where my mouth is) buying an OS Giken Super Lock will help your course times much more then shocks and springs.
After that, go to 2.5" ID springs front and rear and then you can buy whatever spring rate you want, in 25 lb. increments, for $45 each. Also, buy the best shocks you can afford. Stay away from the majority of the JDM stuff because they generally have too much compression damping and some of the lower priced shocks have amazingly inconsistent valving from shock to shock.
After that, go to 2.5" ID springs front and rear and then you can buy whatever spring rate you want, in 25 lb. increments, for $45 each. Also, buy the best shocks you can afford. Stay away from the majority of the JDM stuff because they generally have too much compression damping and some of the lower priced shocks have amazingly inconsistent valving from shock to shock.
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