Suspension Packages and Usage

[Flash's Owner]

I have been asked by several people to clarify which parts make up which of the suspension levels. Here is a compilation of this information, with spring rates and loads.

I hope people understand what a check height and check load mean for a spring. The check height is not the same spring length as any particular loading.

Some definitions:
LE5 = Base naturally aspirated 2.4l engine
LNF = 2.0l turbo SIDI
SDT = Street Edition
FE2 = the option code for the base suspension
FE3 = option code for uplevel suspension

You will notice that the SKY LE5 front spring has a higher load. In general, the SKY is slightly heavier due to option content, differences in structural mass, etc. and requires a slightly higher load spring to keep the trim height in specification.

Application				Front Spring 				Rear Spring
			Frt Shock	(chk ht. = 		Rear Shock	(Chk ht. = 	
					211.5mm)				217.5 mm)
=====================================================================================================

FE2 LE5 Solstice	15278695*	15244327		15278696*	15280026
2006 MY			Code 9??*	(3600N - 22.5 N/mm)	Code 9??*	(3700N - 31.0 N/mm) 	
					[Tag = Lt Grn]				[Tag = Tan]
=====================================================================================================
FE2 LE5 Solstice	15224875	15244327		15236924	15280026
2007+MY			Code C404	(3600N - 22.5 N/mm) 	Code C406	(3700N - 31.0 N/mm) 	
					[Tag = Lt Grn]				[Tag = Tan]	
=====================================================================================================
FE2 LE5 SKY		15224875	10376421		15236924	15280026
			Code C404	(3800N - 22.5 N/mm) 	Code C406	(3700N - 31.0 N/mm) 	
					[Tag = Dk Grn]				[Tag = Tan]	
=====================================================================================================					
FE3 LNF (Non Z0K)	15901220	15784872		15901221	25787858
(All Non-Z0K LNF Kappa)	Code C646	(3800N - 30.5 N/mm) 	Code C648	(3900N - 40.0 N/mm)	
					[Tag = Brown]				[Tag = Purp Stripes]	
=====================================================================================================
LE5 Z0K Solstice	15901220	15906534		15901221	15906532
also Street Ed. SDT	Code C646	(3100N - 30.5 N/mm) 	Code C648	(3250N - 40.0 N/mm) 	
					[Tag = Lt Grn Stripes]			[Tag = Lt Blu Stripe]	
=====================================================================================================
LNF Z0K Solstice	15901220	25849163		15901221	25855626
			Code C646	(3100N - 37.0 N/mm) 	Code C648	(3200N - 50.0 N/mm)	
					[Tag = Orange Stripes]			[Tag = Yellow Stripe]	
=====================================================================================================
GM SPO Perf Parts	88965295	88965293		88965296	88965294
			Code C388	(3450N - 37.0 N/mm)	Code C390	(3350N - 50.0 N/mm)	
					[Tag = White]				[Tag = Lavender]	
=====================================================================================================

* The 2006 Solstice had a different shock valving and shorter jounce bumper with a different rate progression.
The 2007 FE2 SKY, introduced early 2006, had a revised jounce bumper and a better shock valving to work with the new jounce bumper.
This was well-received, so the changes were rolled into the FE2 Solstice in 2007 model year and parts commonized.
The 2006 shocks are not available in service, both old and new jounce bumper are available in service.
2006 Solstice are all FE2 and all have the 15159045 jounce bumper.  All 2007+ kappa have the 15823830 Jounce bumper.


			Front 		(2) Frt		Rear		(2) Rear 
			Stab Bar	Insulator	Stab Bar	Insulator
===================================================================================================
FE2 LE5			10342785	15887219	10342786	10350105
			27.2 x 4.5mm	27.2mm		24.2 x 3.0mm	24.2mm
===================================================================================================
FE3 LNF Non-Z0K		15224873	25789241	15224878	15224881
& LE5 Z0K		33.3 x 4.5mm	33.3mm		25.4 x 3.0mm	25.4mm
& SDT (street edition)
GM SPO Perf Parts							
===================================================================================================
FE3 LNF Z0K		25855621	25789241	25855622	25855623
			33.3 x 6mm	33.3mm		27.2 x 6mm	27.2mm
									Also needs
									25855624 clamps
===================================================================================================

I also added it as a txt file.

The shocks have a sticker on them with a code. Springs usually have a tag that is a specific color and has the part number of the spring on it.

Also, keep in mind that the Z0K (both LE5 and LNF versions) are built with two spring seats. Out of the factory, the trim height is within specification with both spring seats, which was necessary due to several areas in the assembly plant that prevented a lower car from getting through the system, as well as shipping limitations at the intended ride height. It is up to the owner to remove this 2nd spring seat/spacer to set the car to intended carrying height. This option was lower cost when compared to other options, such as lifts and/or disposable spring stuffers.

You will also notice that the same shock is used for the LNF Z0K as is used for the lower spring rate cars. This shock is not fully optimized for these higher spring rates, and the GMPP shocks will be closer but oriented toward heavier rebound damping than is necessary for the increased spring rate, and significantly tighter bypass (bleed), which is typically more desirable for autocrossing vs. street usage or road racing. It is assumed that anyone buying an LNF Z0K for T2 or serious AS autocross would be replacing stock shocks, no matter how they are tuned, with their own choice in Penskes, Olins, Konis or other racing or adjustable shocks.

[stonebreaker]

Quick question: On the spring specs, I kind of figure the N/mm is Newtons per millimeter, since I'm used to seeing spring rates in pounds per inch, plus converting Newtons per millimeter to pounds per inch works out to 211 pounds per inch in the case of the LNF Z0K front spring. But what is the first number? For example, for the LNF Z0K solstice, the front spring is listed at (3100N - 37.0 N/mm). The GMPP front spring is listed at (3450N - 37 N/mm).

I'm guessing that the 3450N is the force needed to compress the GMPP spring to the check height of 211.5 mm? And that since the load for the GMPP springs at check height is in the middle of the FE3 and Z0K spring loads, the car will sit somewhat lower than stock but higher than the Z0K?

3800 - 3450 = 350N

350 N/37N/mm = 9.46mm = .37 inches, or about 3/8ths of an inch lower than stock, right?

[Flash's Owner]

Originally Posted by stonebreaker Quick question: On the spring specs, I kind of figure the N/mm is Newtons per millimeter, since I'm used to seeing spring rates in pounds per inch, plus converting Newtons per millimeter to pounds per inch works out to 211 pounds per inch in the case of the LNF Z0K front spring. But what is the first number? For example, for the LNF Z0K solstice, the front spring is listed at (3100N - 37.0 N/mm). The GMPP front spring is listed at (3450N - 37 N/mm). I'm guessing that the 3450N is the force needed to compress the spring to the check height of 211.5 mm?

that is correct, the check load is the load to compress the spring to the check height. There are different check heights for front and rear.

[snaponbob]

Great stuff, Steve. Thanks a lot.

[stonebreaker]

What's the purpose of different check heights?

[Flash's Owner]

Originally Posted by stonebreaker What's the purpose of different check heights?

They are the attribute of the springs that ensures they yield the proper trim height when installed in the vehicle. More accurate than "free length" because of changes and non-linearity of the springs at the ends of the coils.

[Chemist]

Originally Posted by snaponbob Great stuff, Steve. Thanks a lot.

Yes, thank you! I'm running the GMPP suspension on my 2006 Solstice. It's good to have the ID numbers for all the parts, should I need them.

And, ... the shock and spring rate information is always good to have.

[stonebreaker]

Originally Posted by Flash's Owner They are the attribute of the springs that ensures they yield the proper trim height when installed in the vehicle. More accurate than "free length" because of changes and non-linearity of the springs at the ends of the coils.

Thanks, I think you pretty much solved my speed bump problem.

[AdamVIP]

This is probably the single best thread in this section of the forum. Thank you.

[Chemist]

Flash's Owner,

It appears that one of my GMPP rear shocks is leaking (after only 4 months of use ). In as much as I bought these off of eBay, I'm without a warranty. Can I replace the shock with the FE3/Z0K shock (using the GMPP spring)?

Thanks.

--Chemist

[Flash's Owner]

Originally Posted by Chemist Flash's Owner, It appears that one of my GMPP rear shocks is leaking (after only 4 months of use ). In as much as I bought these off of eBay, I'm without a warranty. Can I replace the shock with the FE3/Z0K shock (using the GMPP spring)? Thanks. --Chemist

You want to replace a
P/N 88965296 code C390 shock
with your
stock P/N 15901221 Code C648 shock, right?

You can do it, sure. Physically they are the same travel, but you will have two different performing shocks on either side. Some potential ride irregularities may show up, but then again you have been running with a reduced performance part since it started leaking anyway. That is a bummer, the leaky shock deal.

A new part is about $170 or so if you get close to dealer cost. If it were me, I would probably do it, and see if it makes much of a difference in handling or ride symmetry.

If so, I would even consider changing them both back as a pair. My guess is you would probably have an increase in transient understeer (corner entry), and a small bit of pitch in large ride swells because of the lower amount of rebound damping with the increased spring rate of the GMPP spring, but it is not a combo I have ever tried myself.

[Chemist]

Thanks. I had planned on replacing both for reason you listed, to have the same performance on both corners. I'm going to see what price I can get for the 88965296 shock locally. I've got a line on the 15901221 shocks rather inexpensively ($70 each) and will go that way if the others are way too much $$

I do appreciate the rapid post.

--Chemist

[TRIBALMASTER65]

I have a question in reguards to the "two spring seats". If i understand this correctly can we can lower the car to the second seat? and if so is there a thread to help?

Second, i have a question about suspension, what can i do to stiffen up... i am doing the turbo tune and have heard about this backbone? to reduce wheel hop? is any of this nessary? or is the GXP stock suspension good enough?
Thanx in advance!!! [quote=

Also, keep in mind that the Z0K (both LE5 and LNF versions) are built with two spring seats. Out of the factory, the trim height is within specification with both spring seats, which was necessary due to several areas in the assembly plant that prevented a lower car from getting through the system, as well as shipping limitations at the intended ride height. It is up to the owner to remove this 2nd spring seat/spacer to set the car to intended carrying height. This option was lower cost when compared to other options, such as lifts and/or disposable spring stuffers.

You will also notice that the same shock is used for the LNF Z0K as is used for the lower spring rate cars. This shock is not fully optimized for these higher spring rates, and the GMPP shocks will be closer but oriented toward heavier rebound damping than is necessary for the increased spring rate, and significantly tighter bypass (bleed), which is typically more desirable for autocrossing vs. street usage or road racing. It is assumed that anyone buying an LNF Z0K for T2 or serious AS autocross would be replacing stock shocks, no matter how they are tuned, with their own choice in Penskes, Olins, Konis or other racing or adjustable shocks.[/QUOTE]