I've noticed this many times in the forums that the 350z D-Specs are recommended over the G35 version. I found that they are indeed different part numbers, so I called Tokico to get the scoop and see what the difference is. Basically they told me they have the same bump and rebound specs, however, the 350z version is slightly shorter.

With that in mind I don't see any reason to get to 350z version. If you are using lowering or 350z springs, I guess it doesn't really matter which shock you have. But, if you are running on stock springs (or think you ever will again), you will run the risk of over extending and damaging the shock if you go over too large of a dip/bump. If there is no difference in the dampening characteristics, than there is no need to run the 350z version of the D-Specs.

Just thought I'd share...

Mike

 

good find CrazyMike. i'm sure you've anwered lots of ?'s people had regarding D-Spec's.

 

Good find. So are there separate part numbers for D-Specs for the G35 Coupe and G35 Sedan? Or is there just one part for the both the coupe and sedan? I ask this because we know all the stock suspensions are different in height. The G35 sedan stock shocks are the tallest. The G35 coupe stock shocks are about .5 inch shorter and the 350z stock shocks are about 1 inch lower.

Edit: I think I just answered my own question. Here is the part number from Tokico's website.

02-04 Infiniti G35
DSP-7

03-04 Infiniti Coupe
DSP-7

Looks the same to me. http://www.tokicogasshocks.com/car/d-spec.html

 

dklau33,

The G35 coupe and sedans both take part # DSP-7 and the 350z takes the DSP-9 from what I've found. I'm not sure how much tollerance are built into these - can they take an extra 0.5-1"? Obviously, at least 0.5" if the coupe and sedan take the same version. If the valving on both is truly the same, I wouldn't bother with the DSP-9s.

I wish I could give a review on the D-Specs, but I won't get mine installed for another 3 weeks or so. Don't have time right now and there isn't much sense in doing it until I can take off the snow tires anyway

Mike

 

OK, you beat me to it

 

if the DSP-9 is shorter...
will that mean it will be less of a chance for the car to bottom out? ( if u have lower 1" or more)
if it is ture then the DSP-9 is better
well...i don't really know about this
can some one explain plz!

 

The suspension is limited in travel by rubber bump-stops - not shock absorbers. Adding different springs does not alter the bump stop height, just the equilibrium ride height. Lets say you have two cars--one stock and one with 1.5" lowering springs. Just sitting there, the one with aftermarket springs sits 1.5" lower than stock. If you added weight to each car until they were completely loaded & the suspension ran out of travel (i.e. they rest on the bump stops), both cars will be at the same height.

It was hard to word this one. Make sense?

 

That's interesting about the height dif.

I'm pretty sure that I've seen a post by Gsedan35
where he compared the two & found very little dif in the lengths.

If I find it I'll post the link.
I ordered the DSP-9 myself,.... waiting for delivery.

 

Makes sense to me,

But, I think that the length difference has more to do with where the median sits.
The shock lenghth should be optimized to have equal travel in each direction

 

Oem G sedan shocks vs oem Z shocks,
Front: Z shock body is 3/4" shorter, extended piston rod length is 3/4" shorter
Rear: Z shock body is 3/4" shorter, extended piston rod length is 3/4" shorter

350Z D-spec shocks vs oem sedan shocks
Front: both shock body lengths are the same, D-spec piston length is 1/4" shorter
Rear: D-spec shock body is 3/8" shorter, extended piston rod length is 1 3/8" shorter

Question I would want answered is this. If I reinstall my oem sedan rear springs with the oem Z shocks in place. Then jack the car up, extending the suspension fully in the process. Will the shorter Z shock still be leveraging downward pressure on the suspension? When I remove the bottom bolt, and move the shock off the bottom mount, how much further down will the shock go once it's free of the bottom mount?

 

Reason I advocate getting the Z D-specs is to avoid the chance that the G spec shocks might be valved softer. The Z D-specs do not match the level of stiffness promised by Tokico and I'd would not care to find out the G one's are in fact softer. This based on a ride and drive with the Z D-spec shocks first hand.

 

I guess I started this thread based on what I was told by the "technical" guy at Tokico stating that he himself had installed the D-Specs on both G35s and 350zs and they were valved nearly identically--but they are different lengths. I wanted to get the actual spec sheets for both, but they wouldn't release that information to me. BS I think. I don't think force curves should be proprietary info, but who knows...

I'll get these installed in a few weeks and get to playing on them, we'll see if they are truly an improvement over stock (they better be).

BTW - I could use some of your insight, Gsedan35, on my Tuning procedures thread I also started. Any ideas? https://g35driver.com/forums/wheels-tires/42748-tuning-procedure-autocross-setup.html

 

If one is going to go with the Z D-Specs, one might as well go with OEM Z springs too IMO. The drop is only about an inch. Not that bad and it is better matched suspension travel wise.

 

I can agree with that. I just wouldn't run the 350z D-Specs with the stock G35 coupe or sedan springs.

Personally, I don't think the G35 shocks will perform any differently when matched with the 350z shocks. The resistance the shocks provide should be nearly perfectly linear throughout most of their travel. Nothing is ever that ideal, but I think the shock design is simple enough for that to be essentially true. I guess I could be wrong there and maybe all shocks are "progressive" but I really doubt it...

But, for the sake of argument, if you want to run the 350z D-Specs and 350z springs together, that should be just fine. You have my blessing

 

Be sure to post back with a detailed review of your setup after you get it installed. And take pics!