Body stiffening/improvements.

[johnymd]

I am starting a new zed project and the general theme for this one is weight reduction rather than power increase as I've previously done. My blue car had 500hp and weighed 1200kg. This same car was just about perfect when the power was nearer 360hp so I'm aiming for 1000kg and maybe 290hp. I don't want a cage as it will mainly be a road car but I do want the the shell to be as stiff as possible. Ideally I want to use bolt on parts that use existing mounting holes. In my head I'm thinking along the line of triangulating areas with small tube linking the rear quarters just behind the seats with top seatbelt mounts and strut towers plus strut brace. Then triangulate the front towers to baulk head. These are just ideas bouncing around in my head.

Any other ideas? or suggestions of ready made/original datsun parts.

 

[Rob Gaskin]

If it's a road car don't worry about stiffening it.

The first job was always to seam weld but if you aren't stripping the car that's not an option.

 

[johnymd]

But I do worry Rob or more to the point, these things interest me. I just love engineering and the engineer in me always wants to improve things. We can't change who we are and i just don't want to change.

The car is stripped to a shell with all paint and coatings removed so now is the time to think about these things and weld in and mountings. I have seen to air tube to sill diagonal brace used quite a lot so that's an easy first thing to install. I will probably use the Top end Performance strut braces I used on the silver car. Then there's the T3 brace I had forgotten about: https://technotoytuning.com/nissan/260z/240z-260z-and-280z-racing-harness-bar

 

[zbloke]

If you're keen to use existing mounting holes, how about fabricating something that uses the OEM captive nuts in the rear inner 3/4 panels that are for the works race/rally - sports option, H frame mountings and building your triangulated frame from there?

 

[johnymd]

I had considered using these to attach a harness bar but I think it may be too far forward. Could still use as a mounting point though

 

[peter_s]

I think as Rob says, you'll see a dramatic improvement by seam welding the body.

Connecting the strut towers will make a big difference too. I'm very happy with the T3 parts I have bought, incl the bracing.

I'm also thinking a lot can be done underneath the body by reinforcing the mounting points of the chassie. T3 has really nice parts for the rear diff and mountings that will also stiffen up the whole rear subframe.

If you want to custom build things take a look at the BMW M3 (F80) and M4 (F82). There are tons of chassis bracing going on from the factory. BMW did a great job with chassis flex on that model. They reinforced a lot both above and below.

Here is the rear, you can see the aluminium scaffolding running forward.

Here is the stock front sub frame:

Check this video out as well:

 

[uk66fastback]

My old Mustang had immense chassis rails which enabled me to fit one of the X-shaped cross braces underneath ... not sure whether anything like that is available for the Z - or whether there is the room.

The floor supports are often extended right to the back for extra rigidity. I wouldn't want to incur the 'Wrath of Albrecht' by calling them chassis rails.

This X-piece was a kinda subframe connectors affair that joined in the centre - you can see it in the pic below of my car.

 

[peter_s]

That's a nice brace! Heavy but looks great

 

[zbloke]

I had considered using these to attach a harness bar but I think it may be too far forward

Someone over on Hybridz did exactly that it it looked pretty good too - I had a quick search on there but unfortunately couldn't find the thread otherwise I'd have put a link to it for you

 

[atomman]

I had considered using these to attach a harness bar but I think it may be too far forward. Could still use as a mounting point though

I'm sure Home Built by Jeff did a brace using those mounts with a bend each end to get the bar back a bit,

 

[arcdef]

Apex engineering do a few nice braces, specifically some for behind the front fenders. Could probably be replicated by someone experienced in welding. They also do the triangulated front strut brace and a 'x' rear strut brace.




https://www.apexengineered.com/store/p67/Front__Fender_Brace.html

 

[Alphabettispaghetti]

I love the weld quality on that apex stuff..........

 

[Rob Gaskin]

I love the weld quality on that apex stuff..........

But look at the car. Wrong priority.

 

[Alphabettispaghetti]

But look at the car. Wrong priority.

I was being sarcastic about the apex welds.

Not great, however thats how a lot of the US cars seem to be modded.

 

[arcdef]

Still a good example of some different bracing that can be replicated here.