Harness Bar

[MONZTER]

I need to build a harness bar that will be used without a roll bar. I am going to mount it horizontal above the wheel tubs level with the openings in my seat, about 3" back from the seat. I am thinking about using some 1-3/8x0.83 wall CRMO that I have. Do you guys think this will be good enough as an autocross only set up.

 

Thanks Jeff

[heavy85]

Why not weld it between the towers? Autox doesn't really take much abuse on belts.

 

Cameron

[MONZTER]

Thanks for the Reply,

This is my daily driver, and I don’t want to weld anything to the body. The car is still original paint and never in an accident, so I want to keep it for restoration. Besides, I was reading on one of John C. post that you want the belt to mount close to the seat. I am really just looking if there are any regulations on wall thickness and bar diameter for local autocross events

[Armand]

Well what class do you plan on running in?

[MONZTER]

I run in a class called CSM, its not a national class, just fun local stuff here in Southern California, my friends with Z,s also run this class. I have not run for over a year and I am getting it back up and going

[Bartman]

Jeff,

I don't know the requirements for a harness bar, but I'm interested in one for my setup as well. There was a 240z at the Japanese Classic Car Show that had one installed and it looked like what your describing.

 

BTW - Are you going to the MSA Performance Driving Event this weekend?

[JMortensen]

Thanks for the Reply,

This is my daily driver, and I don’t want to weld anything to the body. The car is still original paint and never in an accident, so I want to keep it for restoration. Besides, I was reading on one of John C. post that you want the belt to mount close to the seat. I am really just looking if there are any regulations on wall thickness and bar diameter for local autocross events

I've never seen regulations like that for a local autox. Most of them just refer to SCCA regulations, so you might check there, but I don't recall seeing anything there either. You might consider bolting on a strut tower bar and connecting your seatbelts there, at least you'd get a chassis stiffening side benefit from the bar installation.

[MONZTER]

Hey Guys,

I don’t know about anything other than 240's, but my cars have 4 threaded holes in the chassis right under the 1/4 window that have a recessed flat spot. I mode some plates that bolted to them and welded the bar between them. It worked out to be the perfect height and position for the belts. No cutting or welding to the chassis and it unbolts with no problem. I'll take some pictures to show you soon.

 

Bart I will be at the MSA Autocross, trying for the first time in a year to be in control, this time with a harness. Looking forward to seeing you there.

 

Jeff

[JMortensen]

Hey Guys,

I don’t know about anything other than 240's, but my cars have 4 threaded holes in the chassis right under the 1/4 window that have a recessed flat spot. I mode some plates that bolted to them and welded the bar between them. It worked out to be the perfect height and position for the belts. No cutting or welding to the chassis and it unbolts with no problem. I'll take some pictures to show you soon.

That is where the original Nissan rally cars' roll bar bolted up and should be plenty sturdy for a harness bar. Still, why not get the extra benefit and brace the strut towers directly?

[MONZTER]

That is where the original Nissan rally cars' roll bar bolted up and should be plenty sturdy for a harness bar. Still, why not get the extra benefit and brace the strut towers directly?

 

Really, did they also bolt up to the two sets of holes in the roof bar where the dome light is? Do you have any good pics.

 

I already have a strut tower bar. And it seems to do the job. If I made the strut tower bar stout enough and bolt in I am afraid it would change my set-up. Also the belts will have to go back at an angle a longer distance, not as good from what I have read.

 

Here are some pics of it as I made it this afternoon at lunch break. What do you think? I feel it should be OK now that I know what the holes were for..

 

 

 

 

 

[proxlamus©]

Monzter do you own a welder and do the welding yourself?!

 

Your a mad man I tell you!! The welds are exquisite!

[Armand]

REALLY nice welds! If you put the original interior covers and make a hole for the harness bar that slips right over the bar that would look SWEET.

[JMortensen]

Really, did they also bolt up to the two sets of holes in the roof bar where the dome light is? Do you have any good pics.

No, but it's been discussed before so you might search. I think Alan posted some pics a while back.

 

I already have a strut tower bar. And it seems to do the job. If I made the strut tower bar stout enough and bolt in I am afraid it would change my set-up. Also the belts will have to go back at an angle a longer distance, not as good from what I have read.

I think you could do a lot better than that strut tower bar. The angle to a strut bar is within spec as I recall, and its really not that far from the seat. I've seen many cars set up that way and that's the way mine will be as well.

 

Here are some pics of it as I made it this afternoon at lunch break. What do you think? I feel it should be OK now that I know what the holes were for..

I would have no qualms about your harness bar whatsoever.

[MONZTER]

Hi Jon,

Thanks, ya I did some quick searching for Rally Roll bar/ bolt in roll bar/ and safari roll bar, with not much luck, I'll keep looking.

 

I know the strut bar I have looks inferior, but I have tried solid bolt in styles in the back and front and it did throw off the balance of my car. I made a nice triangulated solid bolt in bar for the front only to cut the diagonal supports off after the car started to understeer really bad. I switched back the simple heim joint bar an it’s great. Same thing in the rear, not as dramatic but it upset the balance.

 

The way I see it is like this. If the car is going to have a stiff chassis it needs to be balanced and stiff equally front middle and rear. What you’re doing for example. If you only stiffen the front, and or rear it messes the balance up. People who have used the PDK front setup without a cage have had problems, so I have heard. I think leaving the front and rear soft and balance works for me. Maybe its wrong, but I like it. I know on the road bikes I design this is defiantly the case when working on the carbon lay-ups. too stiff in the rear is bad if the front is not a match. A fully soft balanced frame will always handle better and turn in better than an unbalance frame. I think when I get my cage going in my other car the bar in the back will work perfect. Hey are you going to the MSA driving school? Your welcome to drive my car, and see what you think, its still NA but a lot of fun.

 

Jeff

[MONZTER]

Ah Ha, found it Jon, different forum but thanks for the Alan T tip (should have figured)

 

http://www.classiczcars.com/forums/showthread.php?s=&threadid=7844&perpage=15&pagenumber=1

[JMortensen]

I know the strut bar I have looks inferior, but I have tried solid bolt in styles in the back and front and it did throw off the balance of my car. I made a nice triangulated solid bolt in bar for the front only to cut the diagonal supports off after the car started to understeer really bad. I switched back the simple heim joint bar an it’s great. Same thing in the rear, not as dramatic but it upset the balance.

 

The way I see it is like this. If the car is going to have a stiff chassis it needs to be balanced and stiff equally front middle and rear. What you’re doing for example. If you only stiffen the front, and or rear it messes the balance up. People who have used the PDK front setup without a cage have had problems, so I have heard. I think leaving the front and rear soft and balance works for me. Maybe its wrong, but I like it. I know on the road bikes I design this is defiantly the case when working on the carbon lay-ups. too stiff in the rear is bad if the front is not a match. A fully soft balanced frame will always handle better and turn in better than an unbalance frame. I think when I get my cage going in my other car the bar in the back will work perfect. Hey are you going to the MSA driving school? Your welcome to drive my car, and see what you think, its still NA but a lot of fun.

There is more than one way to change the balance, and making the chassis more flexible would not even be on my list. One thing that Cary (tube80z) has repeatedly mentioned over the years is balancing the front and rear suspensions so that they move relatively equally when loaded. This puts less twist in the chassis. So if you have different roll resistances front and back, more twist of the chassis. Balance them out and the result is less torsion.

 

The offer to drive your car is generous and I'd love to just see your car in person as the workmanship looks so good, but to drive or fly 1200 miles for MSA is not really feasible. I'm not much for car shows anyway, I only went to MSA once when I lived in SoCal.

[buZy]

Really, did they also bolt up to the two sets of holes in the roof bar where the dome light is? Do you have any good pics.

 

I already have a strut tower bar. And it seems to do the job. If I made the strut tower bar stout enough and bolt in I am afraid it would change my set-up. Also the belts will have to go back at an angle a longer distance, not as good from what I have read.

 

Here are some pics of it as I made it this afternoon at lunch break. What do you think? I feel it should be OK now that I know what the holes were for..

 

 

 

 

 

 

 

Looks like a good product! You could sell these! (I smell a future group buy.) Very Nice work!!!!

[JSM]

Pro's on the bar: it sits nice and straight, easy to bolt up and close to the seats.

 

Con's and this is a big one to me, you can't recline the seat much at all.

 

What I was going to do was a similar bar, but mounted higher to where the stock shoulder strap actually bolts in. This would be simple bolt in option also. Then no seat issues.

[MONZTER]

There is more than one way to change the balance, and making the chassis more flexible would not even be on my list. quote]

 

We both agree 100% I guess what I am saying is I am too lazy to change my set-up:bonk: as it works pretty good as a double duty daily driver / couple times a year autocross car

[jerryb]

OMG....I always wondered what those threaded holes were for and wanted to build a bar that bolts right up to them...HAHAHAHAHAHAHAHAAAAAA! I figured it was a decent stiffening point as well as a good spot for belts

 

Damn..I should have asked!

 

Thanx!!

 

 

That is where the original Nissan rally cars' roll bar bolted up and should be plenty sturdy for a harness bar. Still, why not get the extra benefit and brace the strut towers directly?