Chassis Strengthening of Old cars.

[KE25-KP30]

Hey, just wondering what any of you have done, or have heard of being done for strengthening the chassis of an old (i.e KE25) car when later model turbo engines etc are put in them.

Instead of a roll cage, can other things be done so passengers can still be taken, but the chassis isn't going crack under the strain?

Any ideas/prices etc would be great!!

Thanks.

[Malcolm]

a lot of people using older cars for competition use get them seam welded, or additional spot welds. No idea on cost or anything though, but basically all panel joins (maybe not all, perhaps just high stress areas like around strut towers etc) in the sheet metal making up the frame are either seam welded, or have lots of extra spot welds put on them, to reduce flex. Also some cars have known weak areas which can be reinforced with extra steel etc.
I would definitely like to hear more about this though if anyone has more info, I have been thinking about getting it done on the MR2

[fangsport]

stitch weld around any suspension, engine drivetrain pick-up points, around door and window openings. add a gusset where the chassis rail/bulkhead/firewall intersect.

[NZ_AE86]

Instead of a roll cage, can other things be done so passengers can still be taken, but the chassis isn't going crack under the strain?



Thanks.

What do you mean by taking passengers? The weight of a passenger is not going to make much difference to the chassis strain!
If you are refering to motorsport use then a rollcage is the only way you can take passengers.

[Rick]

Instead of a roll cage, can other things be done so passengers can still be taken, but the chassis isn't going crack under the strain?

You can have a roll cage and still take passengers. I read some where that if the body was then injected with expansion polyurethane foam in all frame structures it reduces flexing with the least amount of added weight. Here is a few pics of an AE-86 which has had a few thousand spot welds added to it



more info :http://www.club4ag.com/faq%20and%20tech_pages/Hot%20Staff.htm

[THA SHZ]

he may be talkin about a normal road car but not havin passengers climbin over roll cages

[fangsport]

Instead of a roll cage, can other things be done so passengers can still be taken, but the chassis isn't going crack under the strain?

You can have a roll cage and still take passengers.

i think he is actuall referring to using the cage as a form of stiffening and the inability to have an operational back seat, well that's how i read the question anyways.

[Rick]

But you can still have a cage and have working rear seats for passengers. What ever. I reckon a combination of a roll cage + seam welding/spot welding (in the right places) + maybe strut braces (font and rear) would be the way to go.

[fangsport]

But you can still have a cage and have working rear seats for passengers.

please explain how? and make it legal?..............

[KE25-KP30]

Wow, so many replies, so quickly....cheers!!

What I was meaning about the roll cage/passengers thing was that to my knowledge it was illegal (and probably a tad dangerous-unless the bars are all padded) to have the likes of a half cage in the back of a car (In my case, a '25 coupé), and still have a back seat for passengers.

I'd like to have the car as a street car, but not only have 2 seats- if you get my drift

Thanks a lot.

[fangsport]

Wow, so many replies, so quickly....cheers!!

What I was meaning about the roll cage/passengers thing was that to my knowledge it was illegal (and probably a tad dangerous-unless the bars are all padded) to have the likes of a half cage in the back of a car (In my case, a '25 coupé), and still have a back seat for passengers.

I'd like to have the car as a street car, but not only have 2 seats- if you get my drift

Thanks a lot.

exactly the way i read it.
stitch welding and some additional braces/gussets.
even with a half cage the back seat is made redundant and un-usable.

[KE25-KP30]

hmm, so I thought. If I planned to use a 3S-GTE (probably a dream, maybe a reality some day ) would the seam welding need to be done to the extent of the AE86 that Rick put the page up of?

Who does it, and what sort of $$$ are you looking at?



Looks like a major!!

[Rick]

The work on the above car is pretty extreme, when I start do my car I dont think I will be doing the underside. I dont see why, if you have a welder and know how to use it, give it a go yourself, might pay to get some advice from someone building up a rally car etc... for the best places to weld.

[Truenotch]

Nah I wouldn't do it yourself unless you really know what you are doing. Doing it wrong can make the chassis morph, so if you're going to do that make sure it doesn't get f**ked up.

[wde_bdy]

You could try something like this combined with a decent strut brace.

Callum

[KE25-KP30]

Looks good Purple_beasty, is that all the strengthening you're doing for the 3t? (and I suppose all the work at the rear end)

Just a bit off the topic, why didn't you (purple_beasty) just put new strut towers in the back of the starlet for IRS? Would that not have been a lot easier than transfering the whole floor?

Cheers

[BlindspottNZ]

im about to seam weld my rx3, its already got a cage and strut bars so it should be rather good


that seam/spot welded AE86 is insane theyre gone nuts on that job

dont know about nz but in aus you have to register your car as a two seater when you have a rollcage

[Leon]

As all the guys above have said ... you put in any form of roll protection (be it a hoop, or a cage) the back seat may not be used (no matter how much padding you put in).

Dirty big metal bars do very bad things to peoples heads, thus why only road legal competition cars are allowed full cages, and then they have a whole series of hoops to jump through.

Roll cage padding does bugger all if you have a crash without a helmet on.

[wde_bdy]

Looks good Purple_beasty, is that all the strengthening you're doing for the 3t? (and I suppose all the work at the rear end)

Just a bit off the topic, why didn't you (purple_beasty) just put new strut towers in the back of the starlet for IRS? Would that not have been a lot easier than transfering the whole floor?

Cheers

Those triangles are 3mm plate, with matching plates on the firewall for them to brace against. Got a lot more strengthening to go, cage will be tied through to strut towers front and rear. Strut brace will go in as well, and looking into removable “brackets” from front of strut towers down to castor arm mounts. Technically you aren’t supposed to brace past the strut towers so the car still retains some sort of crush zone or something, but I need a mount for the coils on one side and intake on the other. Any reinforcement provided is completely accidental, bolts should break in a major smack anyway.

At the moment we are working on tying the front and rear chassis rails together and extending the gearbox crossmember out to the chassis rails, partly because of the exhaust tunnel (rolled up from 2mm steel) we are putting in between the gearbox tunnel and the chassis rail. Floor is also being raised under passengers seat to fit the muffler in, so chassis rails will be run inside the car. Have to bring exhaust out through the sill as well due to the IRS crossmember, so that will all be braced up. Seam welding is on the agenda somewhere too, need to clean all the seam sealer out first though.

For the rear end cost played a big factor, around $1,000 to fit the IRS and no need to fabricate mounts for it which kept the certifier happier. It had the added benefit of stretching the wheelbase 4 inches, and should also be easier to repair when I prang it. Similar reason for not fabricating our own tunnel but using the Carina one instead, its strength and suitability is a known factor for the certifier. We also new it would clear the motor, simply matched the measurements from the engine crossmember to the gearbox crossmember from the Carina.

Callum

[KE25-KP30]

Lol, that starlet's going to be pretty awesome when it's all finished!!

So, in a nutshell, what strengthening would have to be added if I was to put a 3S-GTE in the KE25?

The triangle plate set-up by the firewall, welding around the top's of the strut towers, possibly some on the inside of the car?How about along the sills?

Thanks for all the replies, it's good to look at all the options!!