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S12 Front Crossmember in 240Z


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I have a 71 s30 and I was wondering what the benefits and drawback of installing the S12 cross member in the Z are. I know of one car that has the set up with an RB but I can't get the attention of the owner and I'm still running the L series. I saw the steering rack is changed to the back and the tension rods to the front but how does this change the response of the car and is it worth it? I plan on a lot of street driving, with moderate track/autocross. I've looked for write ups on this and have found nothing.

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Is it worth it? No. Unless you already know all of the reasons as to why it would be better and how the steering ackerman, bump steer, camber progression, and all the other suspensiony crap that I can't explain is going to change, and how to make it beneficial, I wouldn't touch it.

 

You can install an RB motor into a Z with it's normal front cross member.

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Thanks I'm keeping the L-series in the car but I wanted to improve the handling of the car if it helped upgrading to the s12 components I was going to look into sourcing the parts however if it isn't then I was going to leave it alone and work with the factory equipment.

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How will changing the rack position help the handling? It's still McPherson Strut up front, with the same geometry.

 

All you would do is basically turn the front end into a 280ZX arrangement. And that was more a 'parts bin decision' to use what existed on everything else in the product line than any inherent design superiority.

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From what I saw pictures only mind you no one explaining. Is that the S12 crossmember changes the position of the steering rack, allows you to use the forward positioned tension rods as opposed to the rear positioned as the are on the 240z already. And use the 240sx control arms and spindles. Like I said I only have pictures and no explanation as to why and the benefits withheld in such a decision.

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A rear steer car (steering rack behind the front wheel center line) can be setup with better Ackerman angles. Unless you are building a pure race car, can explain Ackerman in depth, and know what your car will need, there's no point on making the change. Also, S12 strut suspension parts are no better or worse the the S30 parts.

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I've done a lot of research about the S12 front subframe and will be installing one into my own car. I got a lot of info from the original person with that swap as well as speaking directly to the shop that did the work for him.

 

My reasons for the swap are a combination of a couple of things:

 

Power steering - nice, but not really enough to justify all the work of the swap

Suspension - I'm nice and familiar with what I like and want in the 240SX world and all of that becomes even easier to swap over if you use the S12 front suspension

Hubs and knuckles - I want to go with a nice 5 lug setup to make finding wheels easier and that is really easy to do using a set of S14 front knuckles that I already have.

 

When you put all the pieces together, it was just easier to use the S12 front subframe than to try and do anything with the stock S30 bits. I also suspect that the more modern setup may be a bit more advanced, but I am no suspension tech. I just know what has worked for me in the past on S-chassis cars.

 

Feel free to contact me and I'd be happy to pass along the info about the swap that I've found out.

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  • 2 months later...

 

My reasons for the swap are a combination of a couple of things:

 

Power steering - nice, but not really enough to justify all the work of the swap

Suspension - I'm nice and familiar with what I like and want in the 240SX world and all of that becomes even easier to swap over if you use the S12 front suspension

Hubs and knuckles - I want to go with a nice 5 lug setup to make finding wheels easier and that is really easy to do using a set of S14 front knuckles that I already have.

 

When you put all the pieces together, it was just easier to use the S12 front subframe than to try and do anything with the stock S30 bits. I also suspect that the more modern setup may be a bit more advanced, but I am no suspension tech. I just know what has worked for me in the past on S-chassis cars.

 

Feel free to contact me and I'd be happy to pass along the info about the swap that I've found out.

 

Im doing the same concept only with s13, using someone else's statement.

 

1) Easy to source parts for CHEAP (Coilovers, control arms, bushings, Diffs[i thought the J30 was a pretty damn stoute diff myself], etc etc)

2) I know and understand the S13 suspension and culture. I have a lot of friends who can get me parts on the cheap.

3) I wanted something different.

4) It widens the stance of the 240Z by a few inches.

 

Im going to cut the whole suspension of the s13 out and graft onto the s30.

 

Do you have any pics of your project?

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