REAR STB for 90-96 Q's...

[AZhitman]

By now all of you have seen Jeff's post regarding modifying a Maxima FSTB to fit our 1st-gen Q's.

To take this a step further, what do you guys think of installing a REAR STB? What impact would it have on chassis rigidity? What would be a good unit to start with (since no one makes one for the Q)? How about a 300ZX rear bar? Is it close enough in size? What are the distances between the towers on the 2 cars?

I'm going to try some experimentation based upon the responses received.

[sultan]

i think the problem with a rear STB is the fuel tank. the fuel tank is in between the strut towers, so the bar would not be straight, it would have to angle around the fuel tank. i don't know if there are any STB's that could be adapted, due to this.

[AZhitman]

Ah - I see. It seemed to me the towers sat up higher than the tank, but it's been a few weeks since I looked in there. Can anyone confirm?

[sultan]

i don't have the rear fascia thing in (can't find it, it's in the attic somewhere) and it looks like the top of the towers is about in the middle of fuel tank. going above the tank looks hard because there is not much room due to the hard metal lines and fuel pump location. i'll take some pics if you want, but i think in order to put on a rear STB it has to go around the tank instead of over.

[Q45tech]

Note the tank retainer [the metal] ties between the strut towers acts somewhat like a RSTB.............a more solid piece could be substituted using the same mounting holes. Weld a solid inch bar in place {--------------}.

[AZhitman]

That crossed my mind when I was looking at it - Perhaps I could simply use the existing tie bar as a template to fabricate a beefier unit...

[QShip]

I like that idea AZ!

[AZhitman]

Yep - Tank and hardlines are in the way bigtime.

Oh well - I still have the front STB to install and the 20mm rear bar...

[maxnix]

I think there is an optional rear bar on the JDM Cima, which is similar in tank location to the G50. Maybe a basis to experiment from here?

[AZhitman]

Brian - I think there's a huge difference. Tank location is nowhere similar to our Q's to my knowledge.

From what I can see, a rear STB would have to extend rearward which defeats the purpose entirely. I'm sure there could be some triangulation built in (like the Neuspeed 4-point units), but this would involve more work than I'm willing to invest.

Oh well - I'll still experiment with beefing up the brace like Dennis suggested.

[Q45tech]

Because of the slop in the rubber silicone isolated rear subframe probably 1/3 or more of the forces are transfered in twisting the frame against the mounts.So a rear STB doesn't have to be as rigid [thick] plus the rear weight is 10% less, except when the trunk or back seat is full.

Since the rear camber is neg. 1.1 degrees minimum [I like -1.5] they have already built in a factor to allow the bending twisting to not let the camber go below 0.5 degrees necessary for the tires to work properly.

But you sure feel the camber changes as the rear twists.

[AZhitman]

Hmmmm - Interesting. This makes a lot of sense.

I'll assume not much can be done about solidifying the rear subframe mounts (for the lay person). I'm guessing there's a half inch (or more) of play in either direction just from this movement alone.

I do notice I like the handling better with about 200 pounds in the trunk (and no other passengers). Probably reduces or dampens some of that "slop" that Dennis references.

[maxnix]

I thought the fuel tank was behind the rear seat bulkhead in the Cima, just like the G50 Q45.

[szh]

By now all of you have seen Jeff's post regarding modifying a Maxima FSTB to fit our 1st-gen Q's.

Was it a Maxima front STB or a J30? Are these the same size effectively?

Z

[AZhitman]

No - It was a 200-up Max (or I30) STB. J30 is a different beast, but the distance between the towers maty be similar.

I'd think a bar for a 300 would be more likely to fit the J, and they're available cheaply as well.

[AZhitman]

No - It was a 2000-up Max (or I30) STB. J30 is a different beast, but the distance between the towers maty be similar.

I'd think a bar for a 300 would be more likely to fit the J, and they're available cheaply as well.

[Eswift]

ive compared the 300zx to the J30 lengths, and the J30 is about 5 cm wider in front, and 7 cm narrower in back. (basically because the 300zx is a sports car and the rear sits wider in back.)

does anyone have the front and back widths for the I30 or maxima, so i can see if it might be a better match for the J30?