Author Topic: Stiffer body - how to do it? (Read 10730 times)

martihe1 · « **on:** August 16, 2008, 05:50:06 AM »

Hi all

My first post to this pretty awesome forum. Does anyone know where I could find info regarding body stiffening. In other words, what parts of E30 body should be welded to make it stiffer?

Thanks for advance

H

Jimmy Lewis · « **Reply #1 on:** August 28, 2008, 07:54:32 PM »

I can't believe no one has posted in this thread, seems cool to me. It's common for people to stitch weld the engine bay to increase rigidity, but I'm not sure I have heard of anyone doing it with an e30. Also there are front strut braces as well rear ones, which people don't rave about. I'm curious myself to the extent of chassis stiffening that can be done to e30s involving bracing and the like. Anyone have any experience with it?

tjts1 · « **Reply #2 on:** August 28, 2008, 09:23:46 PM »

Get an E36

Frankie · « **Reply #3 on:** August 28, 2008, 11:29:21 PM »

Why not E46 m3?...

Well, I think that was not the answer he was hoping for. It's quite common that E30's is track use are welded for extra rigidity. Question is that how it is done.

Boyracer · « **Reply #4 on:** August 29, 2008, 06:57:44 AM »

I can confirm from personal experience that body stiffness wise E46 > E36 > E30

My E36 Sedan body is starting to feel bit flexy, doors seams make annoying noises on bumps etc. My E46 M3 feels like it is hewn from solid piece of metal.

I did read the original question when it was posted but since I do not have any practical knowledge what should be spot welded on E30 to make it more rigid, I did not answer. I guess you should basically spot weld everything you can. But I have a feelign that proper cage tied to car's body in proper places is far better choice than spot welding.

Since my E36 318is is becoming less and less road car and more and more track car, I have thought about building a cage for it. Swiss (Tony) posted some good shit about E36 Supertouring tech on his thread:

http://www.m42club.com/forums/showthread.php?t=4749

Before I was bit apprehensive about putting too much effort on my 318is because if in future I want to have huge horsepower and keep the car road "legal" the car should be M3.

But it seems that iron block S50's really kill the weight distribution (friends stripped and caged M3 is 70 kg heavier on front than rear!) and the engines are still only 3,2 liters max. I can legally put 2,8 or M52 or 3,0 M54 to my 318is which are lighter due alloy block and not much behind on ultimate power capability if well built.

EN318isPDX · « **Reply #5 on:** August 29, 2008, 11:48:02 AM »

Quote from: martihe1;54975

Hi all

My first post to this pretty awesome forum. Does anyone know where I could find info regarding body stiffening. In other words, what parts of E30 body should be welded to make it stiffer?

Thanks for advance

H

Get a solid strut bar that mounts to all the nuts on the top of your shock tower. Than upgrade your stock swaybars and you will out handle any car

E36 < E30 According to every BMW tech I know

Frankie · « **Reply #6 on:** August 30, 2008, 02:15:28 AM »

Hey DUDES!

He is asking about welding and your are offering strut bars. He's asking for beer and you are offering girl drinks

. he is well aware of strut bars.

To my understanding the car is stripped and removed from all sound insulation material. After that it is sand blasted. Then it will be spot welded trough put the body (all seams). He is looking for a website etc. which would describe the procedure in detail.

EN318isPDX · « **Reply #7 on:** September 02, 2008, 01:31:10 PM »

Quote from: Frankie;55747

Hey DUDES!

He is asking about welding and your are offering strut bars. He's asking for beer and you are offering girl drinks . he is well aware of strut bars.

To my understanding the car is stripped and removed from all sound insulation material. After that it is sand blasted. Then it will be spot welded trough put the body (all seams). He is looking for a website etc. which would describe the procedure in detail.

i dont see how you got all this information from his first initial post... weird.. its ok i dont care if you think your new car is stiffer than an old car. Its pretty obviously a 17 year old car is gonna have a few more loose bolts in the suspension but it can be fixed. ANYWAY

I did notice on the cabrio that they did some extra reinforcements to the chassis. Look at the extra welds on a cabrio and you may find the answer you are looking for.

16v of E30 · « **Reply #8 on:** September 03, 2008, 12:02:04 AM »

Quote from: Frankie;55747

Hey DUDES!

He is asking about welding and your are offering strut bars. He's asking for beer and you are offering girl drinks . he is well aware of strut bars.

To my understanding the car is stripped and removed from all sound insulation material. After that it is sand blasted. Then it will be spot welded trough put the body (all seams). He is looking for a website etc. which would describe the procedure in detail.

so do you have some input on where he should look or are you gonna sit there and act like a douche?

Boyracer · « **Reply #9 on:** September 03, 2008, 03:40:02 AM »

Quote from: EN318isPDX;55887

i dont see how you got all this information from his first initial post... weird.. its ok i dont care if you think your new car is stiffer than an old car. Its pretty obviously a 17 year old car is gonna have a few more loose bolts in the suspension but it can be fixed.

Actually, I think he did not refer to original post, just how the spot welding is done generally. So he is actually adding information to this discussion

And it is just not about loose bolts. Every new 3 series generation has torsionally stiffer body straight from factory line, even without taking account the aging effect on older bodies.

I have seen with my own eyes endurance class SEAT Ibiza that had so tired body due fatigue that while it was standing still and you rocked it from left to right you could see the gaps between fenders and hood changes 1/4th of and inch! :eek:

swiss318is · « **Reply #10 on:** September 03, 2008, 08:19:32 AM »

Quote from: Boyracer;55704

...Swiss (Tony) posted some good shit about E36 Supertouring tech on his thread:...

hmm.. who is Tony??

i would say.. stitch-weld the whole chassis.. all seems you can find.. first clean it from colour and then.. WELD WELD WELD.. have fun.. there are at least 100km of welding in front of you..

thats what i am gonna do with my white car.. and then a bolted rollcage and strutsbraces front and rear.. i think that all will increase the rigidity of the car more than enough.... perhaps a sheetmetal here and there too..

but dont forget.. the oldest e30 318is are 20years old!!!

ose30 · « **Reply #11 on:** September 03, 2008, 09:59:19 AM »

I suppose good starting point is to check out how factory did it for example on M3. There are lot of improvments, not just aerodynamical for extra strenght.
Some how i find it out a little bit funny we finns discuss on US based forum in english when there are finnish BMW forums where you you can write finnish

I also suggest you to visit some finnish rally events.There are lots of E30 bodied BMW's. Just disccus with these people, they can give you some useful information.

Here's some finnish low cost rally cars:

EN318isPDX · « **Reply #12 on:** September 03, 2008, 11:27:32 AM »

First thing i noticed was the M3 has a pillar coming out the back of the strut tower.. That's a start... I pointed out earlier that the cabrio has a reinforcement on the top of the front shock towers. No pics though.

ose30 · « **Reply #13 on:** September 03, 2008, 11:34:09 AM »

Reasons why M3 had different rear window arrangement where aerodynamics and the other was extra reinforcement just under rear window. Rear window is the same as normal E30 body uses it has just moved back using glassfibre frame.

colin86325 · « **Reply #14 on:** September 03, 2008, 08:33:38 PM »

M3 front and rear windshields are glued in to provide extra stiffness, unlike the normal E30.