[vdMDerek]

Hi everyone. I'm new to the forum and need some advise on my race car project.

I recently bought a 1964 1.6 Sprint GT (LHD), with the intention to build a race car, to compete in our local Historic racing series and Alfa Trofeo.

The body is in a remarkably good rust free condition. The previous owner stripped the car to a rolling chassis and boxed all the parts.

I like to do things right the first time round and have already done a lot of research and the AlfaBB is a fantastic source of information.

I've done various searches but could not find anything specific on roll cages and seam welding and would like to ask your opinions and experience with this.

I'm looking for a good, strong and light weight roll cage design as well as specific areas to seam weld and strenghten on the body / chassis.

If possible, some pictures would be most welcome.

Thank you in advance.

Derek.

 

[geh458]

Derek,

I haven't done my own car yet from scratch, but there may be one in my future. Might I suggest that you acquire a copy of the Welder's Handbook: A Complete Guide to MIG, TIG, Arc, & Oxyacetylene Welding, it's been revised recently so it probably has better info than the copy I have.

 

[vdMDerek]

Gifford,

Thank you. Thankfully I'm blessed to have a friend who is a professional welder. Unfortunately I have to give him the design of the roll cage and instructions for the seam welding and chassis strengthening.

 

[Alex]

Derek,

Are you in the UK, by any chance?

Alex.

 

[vdMDerek]

Hi Alex,

I live in South Africa.

Regards.

Derek

 

[PSk]

Just incase you don't know: Seam welding means 1" (or less) on (weld) and an 1" (or more) off. Does not mean continuous welds.

If you make the car too strong/brittle the person inside breaks, so please think about crumple zones as well and don't over do the welding.

Best
Pete

 

[vdMDerek]

Thanks Pete, very good advice. I will keep that in mind.

Various "experts" i spoke to, seem to think the roll cage should extend to the shock mounts to improve the cars handling.

My aim is to have a very well designed, yet light weight roll cage.

I've seen a number of different cages on other cars, but don't know which is better.

 

[PSk]

Various "experts" i spoke to, seem to think the roll cage should extend to the shock mounts to improve the cars handling

Yes totally agree, as then the roll cage becomes part of the chassis ... heck you have to carry the weight of it around, it might as well do something as well (not just insurance for that hopefully never happening accident).

Also mount your seat on the cage ... so if you get hit in the side your seat will move with the roll cage.

Pete

 

[Veep]

Thanks Pete, very good advice. I will keep that in mind.

Various "experts" i spoke to, seem to think the roll cage should extend to the shock mounts to improve the cars handling.

My aim is to have a very well designed, yet light weight roll cage.

I've seen a number of different cages on other cars, but don't know which is better.

which one is better... you only know when it `s too late... see the pics on this site of a cage-designer/builder in Holland. I have a cage by this man in my car. Chroom-moly steel saves some kg, but nothing goes above safety in my opinion... Autoschade Wielhoven the driver only had a slightly headache...

and here you find my car, and pics f the cage and welding:
http://www.alfabb.com/bb/forums/picture-room/11149-my-racecar-project.html

 

[vdMDerek]

Baie dankie.

Your car is an absolute work of art and I'm actually going to base my roll cage (and some of the interior work) on your car.

Pictures of your car serve as inspiration to get my car done.

I also like PSk's suggestion to mount the seat on the roll cage, but I'm still trying to get my head around how to build the roll cage to provide anchor points for the seat.

 

[Veep]

As you can see I have a low bar from left to richt just behind the seat What you want is a cage that wil not move (much) with a side -impact. I don`t agree with Psk on that point. So you have to brace l-r. In the front this is almost impossible , but the extesions to the front shock mount will solve that, as well as the extensive seamwelding of the sills . I have seen some cars with side-impact damage, so did the cage builder, and this knowledge we put in this cage. A friend of mine had a serious acident with a healey 3000, with a sixpoint cage... broken pelvis etc etc, one year recovery to function again, 2 year before he could race again...

 

[gtv27]

105 has quite a lot of strength in the sills, so if you tie the cage to that, along with a side impact beam, and put cross bars (in the main hoop and under the dash) you end up with pretty good side protection (noting that is the HARDEST thing to achieve in a cage).

We can't go through the firewall into the engine bay or to the front suspension due to the historic racing regulations here , but is a very good idea if you are allowed.

A common mistake I've seen is where the rear legs attach at the back. Some put plates on the flat panel behind the rear seat or worse on the parcel shelf. These areas have low strength. Is much much better to take the legs to the rear wheel arches. They are a very strong part of the car. The rear shock mounts are another option if you can go through the rear panel into the boot.

 

[PSk]

As you can see I have a low bar from left to richt just behind the seat What you want is a cage that wil not move (much) with a side -impact. I don`t agree with Psk on that point.

Mounting the seat on the rollcage is now a requirement to race a car in levels of motorsport in Australia that require a rollcage.

Why?

When a car gets hit in the side you want to move with your rollcage, because yes it will move. We had a driver die because of this a few years ago ... basically crushed by his rollcage.

Just think of having a spin, maybe hitting a wall and ending up back sideways on the track ... the next car hits yours and is doing like 100+mph ... your cage WILL move!!!
Best
Pete

 

[vdMDerek]

Pete, I fully subscribe to the idea, just have no idea how to practically do it, given the design of the roll cage. Do you have any pictures perhaps?

 

[gtv27]

Mounting the seat on the rollcage is now a requirement to race a car in levels of motorsport in Australia that require a rollcage.

Can you point that requirement out for me? Maybe I am misunderstanding what you are saying, but I can't seem to locate that regulation in the CAMS manual.

http://www.camsmanual.com.au/pdf/general/0611_Schedule_J_Q408.pdf

 

[PSk]

Can you point that requirement out for me? Maybe I am misunderstanding what you are saying, but I can't seem to locate that regulation in the CAMS manual.

http://www.camsmanual.com.au/pdf/general/0611_Schedule_J_Q408.pdf

Also confused, as neither can I. But I do remember when that guy died at Bathurst around 10 years ago that the recommendation afterwards was that seats must be mounted to rollcages.

This Australian roll cage manufacturer site refers to seat mounts: REDLINE SPEEDWAY KIT ROLLCAGES

Best
Pete

 

[genericwood]

I'm certainly not a cage designer, but I suspect the subject is a lot more complicated than is suggested by this thread. The reason to mount the seat to the cage is so you move with the "capsule" that is trying to protect you. Sounds like a pretty good idea, right? But if your seat is mounted to the floor structure, and the floor is properly tied into the frame, you would accomplish the same thing. In this case, the floor becomes part of the cage.

What is equally important is ensuring that your seat BELT mounts move with the seat and the cage. Nothing like having your own harness decapitate you! Also, I routinely see Alfas coupes with the shoulder harness mounted to the rear floor or rear shelf. This leaves you with a very long strap that is often at a sharp angle toward the floor. The longer the strap is, the more it will stretch. And if it angled down behind your shoulders, it will compress your spine in a frontal collision.

Finally, I hope everyone who races their Alfa will consider getting a HANS or similar device. I didn't see the value until I destroyed my car in a frontal collision. I had some serious whiplash. But I was lucky. I could have become another Dale Earnhardt just as easily. I'm sure I now sound like an ex-smoker who has "seen the light". But I'd hate to see any of my friends hurt or killed doing what we love. For what it's worth, the HANS took a little getting used to. But after a few sessions on track, you won't even know it's there.

Erik

 

[PSk]

The accident that caused the change in Australia ... :-(

Greg was indeed a great guy with an in check ego it is often rare for famous motorsportsmen.
Greg,s death was probably the hardest thing I had faced in 25 years of motorsport.
He was killed in the lead car of a 2 car team owned by Ross Palmer Motorsport[RPM] the other car being driven by my son Darren.
He was also my close friend and to have an incident like this happen in your teams first outing certainly makes you think long and hard.
Primarily a HANS device would have helped,however he also sustained seriousinternal injuries from the failure of the side intrusion protection.
In memory of Gregg and for the good of the sport I started on a 7 year campaign for the introduction of HANS systems in Australia.
Unfortunately their final adoption by motorsport regulators came too late for 23 year old Stewart Mc.Coll [VW Works Golf R32]who lost his life at the Same Track in a round of the Australian GTP series this year.
HANS systems were finally approved 1 week before his death.
For all racers and team owners the eventual compulsory adoption of head and neck systems will go a long way to making our sport a lot safer.
RIP Greg and Stewie.

Was not at Bathurst as I first thought.
Pete

 

[156GTASelespeed]

which one is better... you only know when it `s too late... see the pics on this site of a cage-designer/builder in Holland. I have a cage by this man in my car. Chroom-moly steel saves some kg, but nothing goes above safety in my opinion... Autoschade Wielhoven the driver only had a slightly headache...

and here you find my car, and pics f the cage and welding:
http://www.alfabb.com/bb/forums/picture-room/11149-my-racecar-project.html

Walter,

Thanks for this link. I just called the guy and i am waiting for his quotation now.

Cheers,