Chassis bracing

[New-to-240z]

Hey guys, just wondering if anyoone can give me some insight on this product . .

 

JDM - Street bar

 

Its nothing crazy and I'm not looking for a roll bar. I'm mainly looking for chassis bracing. But, what I'm wondering if this is nothing more then a strut tower bar? It looks like it would be a stronger alternative since it braces in other areas, but I want to get your input. He only has one left and I'm not able to weld so I was wondering if this would be worth a look.

 

Or would this be more of what I am looking for.

Another option

 

This is just going to be a weekend driver, maybe a track day once or twice a year. The main reason for this is to stiffen up the frame and help brace it for the extra HP i'm building. (300 - 370HP SR20DET.) I will also be putting in new frame rails and front strut bracing (strut tower to cowl triangle bracing.)

 

Also, would it be better to add on a strut tower bar as well?

 

Thanks for all your help!

Edited May 27, 2010 by New-to-240z

[johnc]

Here's my opinion...

 

1. Installing a roll bar is PRIMARILY a safety modification. If that's not your main reason for doing this then you're just adding weight and making your car slower - regardless of how much stiffer the chassis becomes.

 

2. All of the pre-made bolt and weld-in roll bars only get you about 50% (at most) of the chassis stiffness improvement that you can get from a welded in roll bar that attaches to the rear strut tower.

 

3. Any chassis stiffness improvement is wasted unless you increase your spring rate(s) to take advantage of the increased stiffness.

 

4. Without increasing chassis stiffness in front of the car, increasing chassis stiffness and spring rate in the rear won't get you as much of a benefit because you can't balance the spring rates front to back.

[New-to-240z]

Here's my opinion...

 

1. Installing a roll bar is PRIMARILY a safety modification. If that's not your main reason for doing this then you're just adding weight and making your car slower - regardless of how much stiffer the chassis becomes.

 

2. All of the pre-made bolt and weld-in roll bars only get you about 50% (at most) of the chassis stiffness improvement that you can get from a welded in roll bar that attaches to the rear strut tower.

 

3. Any chassis stiffness improvement is wasted unless you increase your spring rate(s) to take advantage of the increased stiffness.

 

4. Without increasing chassis stiffness in front of the car, increasing chassis stiffness and spring rate in the rear won't get you as much of a benefit because you can't balance the spring rates front to back.

 

@John :

1. Not looking to install a roll bar. This car will be mainly for weekend driving on PCH (the beach) and maybe a auto-X day here or there. Nothing crazy. I'm truly just trying to strengthen the chassis to handle the extra HP I'm putting into it.

 

2. Well, what I'm thinking is that I can use this as it is, and also add a rear strut bar. Both will not be welded, so would this make a large difference in strength?

 

3. I will be moving to coilovers soon. Just not at this very moment. So, stiffer springs will be there in time.

 

4. I will be adding in a front strut tower bar that will connect the strut tower to the firewall/cowl of the car. The coilovers will also be installed front and rear.

 

So, is it worth it?

 

Also, thank you for your insight. I'm new to chassis strengthening, and I'm learning more from this site everyday.

[bjhines]

I have a few ideas for you.

 

1. get the Ebay 8-point in chromoly. The rear braces look like they will attach to a tube welded between the strut towers or to the towers themselves. I like the inside/tunnel diagonals. You would need more diagonal bracing in the rear braces to pass track-tech-inspection.

 

2. Install the PDK fabrication front end kit. and install the PDK rear brace. These do more than the everage strut bars. Or use the design as a guide.

 

3. Your coilover choices are going to need careful consideration. Buy a COMPLETE kit because the struts have to match you spring rates and upper mounts. This also includes deciding which wheels and tires you will use FIRST!!!!!!!!!!!!

 

4. The PDK fab bar does even better. It reinforces the sway bar mount as well.

 

5. The front frame rail underside NEEDS REINFORCEMENT. Many are popping spot welds, especially when stiff sway bars are mounted with soft springs!!!!!

 

6. weld in subframe connectors. These offer significant reinforcement and they add weight low(where it can be tolerated).

 

7. In rear; add horizontal bracing on the underside of the chassis. There are a lot of ways to do this.

a. weld 16guage steel channel to the underside of the horizontal x-member that the rear uprights and the mustache-bar bolt to.

b. Add diagonal braces to the rear suspension hanger/uprights

c. use an alternate rear hanger system like the Arizona-Z-Car rear end/mustache-bar kit.

 

8. Add lower-front X/K-member, bracing the TC buckets, framerails, subframe connectors, and front cross-member together.

 

9. seam/plug weld as many chassis seams as you can manage.

[New-to-240z]

Do you know where I can pick up the pdk braces? I have emailed and phoned him many times and no response yet.

(EDIT : just talked to him and found out that they are waiting for the next production run. This will be at least a few months out until he has them available.)

 

Are there any other companies that sell the same type of bracing?

Edited May 27, 2010 by New-to-240z

[New-to-240z]

5. The front frame rail underside NEEDS REINFORCEMENT. Many are popping spot welds, especially when stiff sway bars are mounted with soft springs!!!!!

 

 

Would Bad Dog sway bar reinforcers do the trick? Sway Bar Enforcement

[bjhines]

The front framerails are too thin, especially on the bottom. You can have a piece of 16gauge steel bent to form a long C-channel and attach it covering the bottom, inside, and top surfaces as a doubler. Drill it full of holes and plug weld it to all surfaces. You also need to open holes for the mounting bolts for various parts. This will give you a good opportunity to seam weld-all of the parts in this area. You may also need to flatten out the bottom surfaces, they get indented from past accidents, especially where the crossmember attaches.

 

The sway-bar mounts can be better reinforced with 1/2" tubes passing through from top to bottom, welded to the framerail on top and bottom. You would use long bolts with nuts that pass all the way through the frame instead of just bolting on to the bottom surface weld-nuts.

 

The inner fender does not meet the framerail with the full thickness sandwich of the strut-towers, inner-fender, and framerail. The tower stampings are an inch short of meeting the framerail lip. I added gussets here to better tie the towers into the framerail. You can also gusset the TC-buckets to the inside of the framerails. Watch out though, you need to relocate some hardlines and wires.

 

The upper frame horns(covered by the front fenders) could also use some reinforcement. There are bolt-on supports for many makes of cars. These are brackets that bolt to the door hinge plates and to the frame horns even with the strut towers. They make an upside-down L with a diagonal for stiffness. I don't know of any brackets made for the S-30. but you can weld a tube from the front tip of the rockers forward and up to the bottom of the frame-horns, in-line with the strut towers.

 

Keep in mind that many areas will require doubler plates to spread loads. This applies to the roll-bar tubes, the various reinforcing tubes, etc.

[New-to-240z]

Good lord! I was just looking to brace the chassis a little bit more for a weekend driver. Is all this really needed? It looks like I'm going to have to take a welding class ASAP. All this information is amazing, and I'm keeping it all for when I'm ready to go all the way. Are these all things that MUST be done if I'm looking to move to around 300+ HP? This car will only be driven on the weekends and it is in pretty damn good condition. I know everyone says that their car has no rust, but I think the PO did a under body coating on mine and I've torn off some of it in random places and it has no rust at all!

I'm not trying to get out of doing this things, but just wondering if they are all necessary for my goals. I'm thinking of doing the fram rail to frame rail reinforcement and then also a roll bar (like the 8-point one on ebay) and strut tower bracing (welded in, not bolted). I'll also be going with TTT's rear-end conversion, and will be beefing up the front diff mounts at the same time since I hear that they are very weak points.)

Edited May 28, 2010 by New-to-240z

[roger280zx]

Very good information. I guess I have something to do with 4x8 sheet of 16ga I purchased a while back.

[johnc]

Is all this really needed?

 

No. It all helps but you can do none, some, or all and you don't have to do it all at one, although its a lot easier and cheaper in the long run to get the chassis work done in one shot.

 

It looks like I'm going to have to take a welding class ASAP.

 

That's a great idea.

 

I know everyone says that their car has no rust, but I think the PO did a under body coating on mine and I've torn off some of it in random places and it has no rust at all!

 

Scrape/tear it all off and make sure.

[proxlamus©]

my previous owner paid to have rust repair done on my car..

 

After sanding through nearly 1/4" thick bondo, I found the shop pop riveted on a piece of aluminum right over the old rust, that wasnt cut out or neutralized. Then after looking at the frame rails, the shop laid cardboard over the rust and coated it in a very thick tar that hardened and "looked" like a rock solid install after hitting it with a wrench. I jacked up the car on this "patch" and to blow me away, the piece fell off .. haha.

 

After lifting the carpet everything looked fine, after lifting the sound deadening.. there was rust.

 

Really gotta be careful with a "rust-free" car lol.

[bjhines]

There is no such thing as rust free when talking about an S30. They had rust before they got to the dealers.

[New-to-240z]

HAHAHA, ok ok ok . . . . I'll start the tear down. I have signed up for a class next month. Tell me if this is good enough . . .

Wire feeder welding is the most popular form of welding, yet most misunderstood. This course will provide hands-on experience in the proper use of welding using various wire feeder-welding machines. The class will cover the following:

 

Safety and Hazards in Welding

Constant Voltage Welding Machines and Welding Guns

Arc and Metal Transfer (both MIG and Flux-Cored) avoiding Spatter and Arc

Stability

Shielding Gases

Starting and Stopping the Arc

Short Circuit Transfer, Globular Transfer and Spray Transfer modes

Weld Test and Welder Qualifications for Certification

 

If you are an artist, a hobbyist working on small home projects such as wrought iron fences, gates, wall decorations, or a professional, including welders, automotive technicians or anyone wanting to learn how to weld using MIG and flux-cored techniques, then this class is for you.

 

Session I: Tuesdays & Thursdays, June 1-July 6

Time: 6:00 pm-10:00 pm

Location: Skills Center 101

Fee: $225

[New-to-240z]

Ok . . Ok . . . Its time to start tearing her apart. I'll be painting soon to, so why not? I've already got a class lined up, its a little expensive, but I think it will cover what I need to know to do the welding ahead of me. what do you think?

 

-----------------------------------------

 

Wire feeder welding is the most popular form of welding, yet most misunderstood. This course will provide hands-on experience in the proper use of welding using various wire feeder-welding machines. The class will cover the following:

 

Safety and Hazards in Welding

Constant Voltage Welding Machines and Welding Guns

Arc and Metal Transfer (both MIG and Flux-Cored) avoiding Spatter and Arc

Stability

Shielding Gases

Starting and Stopping the Arc

Short Circuit Transfer, Globular Transfer and Spray Transfer modes

Weld Test and Welder Qualifications for Certification

 

If you are an artist, a hobbyist working on small home projects such as wrought iron fences, gates, wall decorations, or a professional, including welders, automotive technicians or anyone wanting to learn how to weld using MIG and flux-cored techniques, then this class is for you.

 

Session I: Tuesdays & Thursdays, June 1-July 6

Time: 6:00 pm-10:00 pm

Location: Skills Center 101

Fee: $225

[johnc]

Ok . . Ok . . . Its time to start tearing her apart. I'll be painting soon to, so why not? I've already got a class lined up, its a little expensive, but I think it will cover what I need to know to do the welding ahead of me. what do you think?

 

-----------------------------------------

 

Wire feeder welding is the most popular form of welding, yet most misunderstood. This course will provide hands-on experience in the proper use of welding using various wire feeder-welding machines. The class will cover the following:

 

Safety and Hazards in Welding

Constant Voltage Welding Machines and Welding Guns

Arc and Metal Transfer (both MIG and Flux-Cored) avoiding Spatter and Arc

Stability

Shielding Gases

Starting and Stopping the Arc

Short Circuit Transfer, Globular Transfer and Spray Transfer modes

Weld Test and Welder Qualifications for Certification

 

If you are an artist, a hobbyist working on small home projects such as wrought iron fences, gates, wall decorations, or a professional, including welders, automotive technicians or anyone wanting to learn how to weld using MIG and flux-cored techniques, then this class is for you.

 

Session I: Tuesdays & Thursdays, June 1-July 6

Time: 6:00 pm-10:00 pm

Location: Skills Center 101

Fee: $225

 

In addition to this intro class, take another class focused just on MIG welding, if you can afford it. The flux core stuff is next to useless for doing proper automotive welding.

[JMortensen]

I think there's enough hours there that he'll be fine. I was actually going to suggest a class that has tig as well. My friends took a class that had arc, mig, and tig and having tig seems beneficial, even if only to get some experience before deciding to spend on $600 for a mig or a couple grand for a tig welder.

[New-to-240z]

Well, I'm just looking to learn how to weld roll cages, strut bars, frame rails, our fenders, and some other chassis bracing. (Maybe even exhaust stuff to.

 

I guess I'll have to start saving $$ to buy a welder to. I thought they would be more in the 300 range, but 600?!?! couple G's for a TIG?!? My god, I can barely afford the strut bars hahaha. Maybe I can find someone who has one they can loan me or sell me.

[JMortensen]

You can buy a cheap ass welder for $300 and a really crappy one for $150 or so, but a good Miller or Lincoln 110V will probably run about $600. After the class you'll understand why you want a good one. The welder is not the place to save money in my opinion. A good welder helps a lot, especially when you're welding rusty Datsun sheet metal which is paper thin to start with. If you have to save money on the welder, I'd buy a used good quality Miller or Lincoln.

 

If you have the option a 220V is better, but again, more $$$.

[New-to-240z]

I think I know someone who has one for sale. I'll check out Craigslist too. I'll keep the Miller & Lincoln name in my head when looking. Any model in specific for the tasks I have ahead of me? Will this one MIG welder do all the things I need it to do? (fenders, frame rails, strut bars, etc etc.) Or will I be needing more then one kind?

[Boy from Oz]

...The inner fender does not meet the framerail with the full thickness sandwich of the strut-towers, inner-fender, and framerail. The tower stampings are an inch short of meeting the framerail lip. I added gussets here to better tie the towers into the framerail...

 

Could you post a photo or two on this - it sounds like a very sensible idea. Thanks.