300zx (Z32) springs & struts on a 90 Q45 (G50) [The complete truth]

[gniknave]

Thread created to make this topic easily searchable.

I'm getting a bit of the run around on this topic and want to have the real answer posted in this thread.

So far I've confirmed the following

-Z32 Eibach (pro-kit) springs will not fit directly onto a Q without slight modifications.

-Modifications will include cutting down the spring cushion from the Q to fit the Z32 spring. The Q's cushion is too big, that is why it needs to be cut.

-The number for the front springs in the Eibach Pro-Kit is the sequence of numbers which ends in 001

-The number for the rear springs in the Eibach Pro-Kit is the sequence of numbers which ends in 002

MY QUESTIONS

1. I've heard z32 struts/shocks will fit onto a Q as long as you use the Q's strut mount. Is this correct? Can someone confirm this?

2. Given the weight of a 300zx vs. that of a Q45, should I be concerned about using KYB AGX (adjustables) struts/shocks from a Z on a Q? Would they be any less reliable because they're not for a Q45?

3. Going back to using z32 springs; Does anybody know if its possible to use a Z's spring cushion on a Q45 strut to fit Z Eibachs?

All input from those who have done this, and those who know something about this is much appreciated. I'll post my results WITH GOOD PICS to confirm everything and have the truth on this once and for all...

[DominickJ30]

Wes, chime in here. I seen your posts on the suspensions being interchaneable.

[qship96]

suppliers have separate,different part numbers for a reason.......... fit,stiffness characteristics,strengh?otherwise,whynot significantly reduce inventory parts for both manufacturer and all their vendors?

[elwesso]

I dont want to say anything about the shocks becuase I dont konw. However, looking at the diagrams in the FSMs, they look nearly identical. I know the multilink stuff will work (at least it better, just ordered all SPL adjustable stuff!), but I dont wnat to say anything about the shocks.

Id thought about trying to find a set and if they dont work just resell them at a slight loss.....

[gniknave]

So Wes would you feel comfortable using Z32 shocks on a Q? Would you expect less reliability or about the same? I'm thinking about ordering the KYB AGX setup and seeing how they fit...

[elwesso]

If I knew theyd fit id feel 100% confident to use them... it would certainly broaden our avenues so we didnt have to use the tokicos!!

[gniknave]

Ok so here's the plan.

I checked out the Z32 struts vs. the Q45 struts in ALLDATA. They look different. The Q struts have just 2 mounting holes at the bottom whereas the Z32's have 4 (on the back). This is only in a picture though.

What I did was order the AGX's from my supplier which in this rare case just happened to have them good in stock. While we're making another attempt at putting my springs on the Q shocks, we'll test fit the AGX's and see how they go in. If they fit with little to no modification, I will slap on all 4 of them and leave them on. If not, I can return them at no loss. Win-Win for me.

Check back in a few hours for an update...

[elwesso]

w00t that was easy!

[pdqwrx]

Thread created to make this topic easily searchable.

I'm getting a bit of the run around on this topic and want to have the real answer posted in this thread.

So far I've confirmed the following

-Z32 Eibach (pro-kit) springs will not fit directly onto a Q without slight modifications.

-Modifications will include cutting down the spring cushion from the Q to fit the Z32 spring. The Q's cushion is too big, that is why it needs to be cut.

-The number for the front springs in the Eibach Pro-Kit is the sequence of numbers which ends in 001

-The number for the rear springs in the Eibach Pro-Kit is the sequence of numbers which ends in 002

MY QUESTIONS

1. I've heard z32 struts/shocks will fit onto a Q as long as you use the Q's strut mount. Is this correct? Can someone confirm this?

2. Given the weight of a 300zx vs. that of a Q45, should I be concerned about using KYB AGX (adjustables) struts/shocks from a Z on a Q? Would they be any less reliable because they're not for a Q45?

3. Going back to using z32 springs; Does anybody know if its possible to use a Z's spring cushion on a Q45 strut to fit Z Eibachs?

All input from those who have done this, and those who know something about this is much appreciated. I'll post my results WITH GOOD PICS to confirm everything and have the truth on this once and for all...

OK here are my thoughts.....

If you must use the Q45 top hats with the z32 struts then you still have to modify the rubber bushings on the top hats.

I would guess that the z32 struts have more dampening or are stiffer then the Tokico's we normally use. I don't think they will wear out too much faster because the weights are similar. Heavy cars automatically wear shocks/struts out faster then light cars.

As for the tophat rubber peices-see my first thought. I don't see how they would be any better then a modified q45 part.

And lastly, would I do it again?

The car drives great if you are looking to make a 4500 pound car into a "race" car. That wasn't my goal. I already have a highly tuned 240sx and WRX that ride like sh*t. I wanted sporty, not floaty or bouncy.

I am thinking I might try the stock z32 suspension. The stock springs should be a bit shorter then the q45's and the struts a bit stiffer. All I need to do is modify or make new tophats and I am in. I am going to do a post in the z32 forum and see if anybody would like to make a donation to our cause. If so, I may have a brand new suspension set for sale. I am into it $500.00. Anyway, we will see.

[gniknave]

Ok so here's the scoop..

*The front struts of a Z32 are a bit (2") shorter than those of a Q45. I didn't attempt to mount them and find out how they'd fit because I just didn't think it was worth the time.

*The rear Z32 struts are nearly identical to the ones on a Q45. The only visible difference is the lower spring seat where you'd have to use strictly Z32 springs for them to work. Of course you'd also still have to modify the Q45 upper spring seat (or strut mount?) to make it work as well. Again, this wasn't worth the time to me since I already knew the fronts don't fit.

Pictured are 1 KYB AGX Z32 front strut (left), and the rear KYB AGX Z32 strut (right) [click for larger image]

Q45 front strut (left) Z32 front strut (right) [click for larger]

Spring removal [click for larger]

We cut the Q45 upper spring cushion in all kinds of different shapes and sizes trying to get a fit we'd be confident in. By this point we had decided trying to fit KYB AGX's on the Q might not be something we'd want to try on this car given it's excellent condition. [click for larger]

After the Q spring cushing cutting didnt work, we decided to try a few hoses laying around the shop. We cut them up into all different types of shapes but nothing worked.

As result of all this work I don't have a car this weekend because my left front Q spring seat cushion is shredded to pieces and waiting for the next option. I ordered some Z32 spring seats hoping that maybe those will work. If not, I'll just get a new stock Q spring seat, put it on with the Q suspension and just not have a lowered car. I'm not one to spend countless hours trying to make something work that just isn't meant to work.

We'll find out Monday if the Z32 spring seats will resolve my issue or not.

[pdqwrx]

So from what I can see the z32 front struts might just work perfectly. If you used a set of AGX's with stock Z32tt springs you would in effect lower the Q by about 2 inches and still have almost normal suspension travel. The stock springs should be stiffer then the stock Q's but not as stiff as the z32 Eibachs. Plus we would get adjustable struts. In the rear we would use the AGX's again and use either the Eibach spring because it is already shorter (This would be a good alternative if you have alot of weight in the trunk) or we could cut the stock rear z32tt springs to get the correct ride height to match the front. This would be the most comfortable option.

What sucks about this whole thing is that I just threw away my stock z32tt springs from an old project that I had been storing for several years and didn't think I would ever need. Oh Well.......

Thanks for the R&D work...

LaterScott

[RobertsnewQ]

Did you get the Z32 seats yet?

[gniknave]

Got the parts, but they weren't Z32 seats. The dealership screwed up and sent me the wrong parts. That's ok though because I decided not to go any further trying to modify what isn't meant to fit. I'm going with plan B which would have been plan A if I had known it was an option. I'll post results when I get them.

[RobertsnewQ]

Oh man, don't keep us waiting! I want to hear what plan B is.

[Q45tech]

"in effect lower the Q by about 2 inches and still have almost normal suspension travel"????????

A Q uses a 16" spring that gets compressed to 8" loaded with weight.

When you subtract spring length to bind, you end up with <4" and the bump stop limits that to match a 7" total oem [black or blue] shock extension length.

Actual oem suspension range is +- [3.3------3.45]" unlowered. The shock stroke [7"/2] being the limiting factor.

[RobertsnewQ]

I think he was referring to using the 300zx spring/strut assemblies. Since the lower spring perch is lower on the strut body, and the strut is shorter, it would lower the car without changing suspension travel more than a token amount.

Probably not 2" lower though, since the 300zx springs are higher rate. I'm hoping to do the same thing myself.

[RobertsnewQ]

Got the parts, but they weren't Z32 seats. The dealership screwed up and sent me the wrong parts. That's ok though because I decided not to go any further trying to modify what isn't meant to fit. I'm going with plan B which would have been plan A if I had known it was an option. I'll post results when I get them.

Are you going to keep us in suspense? What did you end up doing?

[elwesso]

Are you going to keep us in suspense? What did you end up doing?

My guess is he got lazy, if i know him right