I am planning to upgrade my 04 coupe (6MT) suspension to either Tein Basic damper or just get the D-Spec with 05 coupe sport tuned rear springs in near future.

My goal is not to drop the car more then a 1" and reduce the on power push as much as possible. So my questions are:

1. Well there be any ill affect if I use the max ride height setting on the basic damper (front -.75" and rear -.15" drop instead of the recommended front -1.5" and rear -.9") ?

2. Between the D-Spec with stock 05 sport tuned spring and the Basic damper. Which one will achieve my goal more closely?


Thanks,
Eddie.

 

i have tein basic dampeners. slammed all the way, but anything is going to be better than stock. the drop may not be as drastic, but the dampening force is still stiffer than the oem. it will def make a difference, you just may get a bit more body roll than the recomended b/c of the higher center of gravity

 

This thread might help:

https://g35driver.com/forums/wheels-tires/59791-people-installed-tein-basics-themselves.html

Adjusting height on basics changes the spring preload in the front, so the ride may suffer if you deviate from the recommended too much. Compressing the spring lowers it, so the ride gets stiffer. Loosening the spring raises it, so you may get a softer ride and clunking if you loosen it off too much.

I got the Flex, you can adjust height without changing the spring preload:

Flex:


Basics:

 

I see. I guess I am go with th D-Spec with 05 rear sping then. The price of Tein Flex is out off my budget

 

Tein Tell's us that the highest you can set the Basics in the front on a coupe is a .7" drop, I find it hard to believe that at that drop that you do not have some preload to keep the springs in place. In the rear, the springs are not on the coilover bodies, so you cannot effect preload when you raise or lower the rears.

Bigger question I have, what is the point of 05 coupe rear springs in your mind? I know how they differ, but I'm not sure what your thinking.

Since the Basic's offer a much higher spring rate increase the car will have a lot more roll resistance. But, D-specs are double adjustable and allow you to tune in way's that the non dampner adjustable basics can't do.

Oem coupe spring rate specs if delivered with oem 17's or 18's
314/342

Tein Basic (twin tube construction, non adjustable dampners )
Spring rates 504/504
Stiffer then oem by F+61% R+43%
Transfers +18% roll stiffness to front
Side Note: Excellent value at it’s price point

2005 coupe oem sport suspension rear springs if installed on a coupe with the regular suspension
314/427
Stiffer then oem by F+0% R+24%
Transfers +24% roll stiffness to the rear

These two setups are what I would recommend if you do not go with the Basics
Tein H-tech 350z (All linear springs) =G35 coupe drop .8"/.7"
Spring rates in lbs 358/375
Stiffer by F+14% R+10%
Transfers +4% roll stiffness to front
Tokico D-specs

oem 2003/2004 350Z springs =G35 coupe drop .5"/.5"
Spirng rate 314/342
Tokico D-specs

(oem 2004.5/2005 350Z springs have 314/427 spring rates)

I would recommend Hotchkis springs, but they will drop the coupe more then your asking for.

 

I wish there was a spring set that would drop the sedan no more than 1/2" with approximately 400 front and 550 rear (not sure on the numbers, I just want a less body roll and nuetral handeling). My 2003 coupe had very little body roll and did not wheel hop!
With my current setup on a section of hwy in chicago (on south bound 294 between 290 and ogden) the car begins to bounce. In stock form it did not do this. Being ignorant I have no idea what is going on.

 

Presented with the right data, a good machine shop could make a adaptor to let you run Tein tapered springs in the front with the spring rate your after. Here's a pic to explain, notice how the spring will not seat, the oem spring seat is not flat and this spring require that. So what the machine shop would make would convert the oem mount to a flat surface, plus be about 1" tall so you can have the 1/2" drop your after. 550lbs in the rear would not be a choice I would go with.



If you have bounce, up the dampning of the Tokico's, should also help the wheel hop. Though when owners get cursed with wheel hop for some reason it doesn' like to be cured, I've never had it. For less body roll I would try adjustable sway's and tune them to get the handling balance you want.

 

I guess I want a stiffer ride but not to reduce too much of the ride height (some speed bump in town are pretty high!)
My impression based on my research on this forum is that the 05 coupe rear spring has the same spring rate as the Z rear srping (427lb/inch) so I elect to go with the oem 05 spring to siffen up the rear end. What I do there is similar to go with Z and DSpec but keep the stock ride height.


Thanks for all your suggestions. I think I need to do more research on this matter.

 

Yes the 05 coupe sport suspension (not regular 05 coupes) rear springs are 427lbs in rate, the same as 04.5+ rear oem Z springs. However, your rear oem regular suspension shocks cannot deal with that much spring, making the D-spec's even more superior then usual, avoiding the effect of underdampning the rear end and blessing the whole car with much better shocks overall. With a 24% increase in rear spring rate like that, I would also recommend installing adjustable sway bars, especially since the 04.5+ Z and the 05 coupe sport suspension likely have stiffer front sway bars (we have a unconfirmed report that the 04.5+ Z's front oem bar is stiffer by 17% to 20%).

Based on what you want, the aftermarket does not give you many option's with springs, that's why what I posted above isn't a long list. Basics will allow you to keep your stock height, but with that much of a spring rate increase you may want to hitch a ride in someone's coupe that has them on, all you have to do is ask for a ride, hopefully someone isn't too far away.

 

If you're planning to keep stock ride height, why not just try some adjustable
swaybars? That'll help you dial in turnability and dial out push-under.

 

Thanks for all the suggestions I think I will go with the 05 sport tune spring and D-spec. Sway bar is the next things but I just want to make a decision on what to get for shock/spring combo. Stillen sway bar will be on after the spring and shock.


Thanks again .

 

Gotcha. Word to the wise. Be very carefull when trying to get the rear springs you want. Work very hard to make sure you end up with a seller that actually has 05 sport suspension springs. Quite a few coupe owner's believe that all coupes have a sport suspension when what they really have is a regular suspension marketed as "sport tuned". Making sure the donor car has oem 19's would really help.

 

Thanks for the tips. I will remembe that for sure!

 

I ordered the adapters from the pit stop. This should raise the rear up some (saggy bottom syndrome, it must be a 30's and up thing)... Anyway, I will up the d-specs before heading home. I am heading to Gingerman the last week of August and Autobahn August 28. I will see what the setup does with the addition of the 350evo sways.

If the front went from the 05 coupe sports to a stiffer spring, say by 20%, shouldn't the rear be increased the same percentage?

 

BTW, the car is very neutral right now. It just bounces every so often and the body roll is more than I want.