"GhostZ" (GhostZ)
09/06/2013 at 05:42 • Filed to: Chassis reinforcement
2
14|
"GhostZ" (GhostZ)
09/06/2013 at 05:42 • Filed to: Chassis reinforcement | 2
| 14 |
Braces, stitch welding, sound deadening, roll cages, and carbon fiber. Tell me the limits.
How much does the stiffness of a Chassis effect its high-speed handling? Can you actually lose forward acceleration due to a weak body? How much of an engine's power can be wasted flexing a body instead of planting it to the ground?
Steel, aluminum, and fiberglass: which is stronger for the weight?
What are the methods used on road cars to convert them to race cars, particularly vintage ones? Bolts VS Rivets VS welding? Seam welds, or spot welds? What techniques to improve the chassis performance did old-school racers do?
What is better, separate Carbon fiber parts, or a steel chassis with welded components? Or a non-modified chassis with bolted-in bracing? How much weight does a roll cage, bolt-in bracing, etc. add to a car? Is the added weight worth it compared to Carbon Fiber parts or welding?
And, ultimately: If you were given the option to build a race car from a road-going vintage chassis for higher speeds/accelleration and cornering from the ground up, would you start by bolting in chassis reinforcement, replacing panels with fiberglass/CF panels, or would a carefully welded chassis be best? Which ones cost the most?
I have many questions and few answers.
Sparf
> GhostZ
09/06/2013 at 06:44 |
|
These are all questions I'd really like to know the answers to as well!
TurboSloth
> GhostZ
09/06/2013 at 06:51 |
|
I'm going to comment, just so I can find this thread later.
The Swedish Bandit
> Sparf
09/06/2013 at 06:55 |
|
You're not alone. I've always wondered if the added stiffness you get from a roll cage actually defeats the extra weight and makes your car go faster. You know, like in fourza.
|
Sparf
> The Swedish Bandit
09/06/2013 at 07:20 |
|
I'd say it does. What I'm most curious about is what methods are "best".
I've been "mentally building" my dream '85 RX-7 GSL-SE track car for the last few days, and I've gotten stuck on how to reinforce the chassis to make it competitive against newer cars.
Arch Duke Maxyenko, Shit Talk Extraordinaire
> GhostZ
09/06/2013 at 08:56 |
|
Sir, one question at a time please.
Yes, get a shoe box and throw it and observe.
Pick up said box and remove the lid. Throw it again and observe.
A bit, but this depends on engine location, power, and suspension design.
God damn you ask a lot of questions, but technically fiberglass, but this widely depends on the type of force and alloys/heat treatment/shape of the metals and the type/resin/and how the fiberglass is laid out.
Depends on how their made ie. body on frame vs unibody and what ferrous or non ferrous materials are used.
Speed holes, lots and lots of speed holes. And triangles, triangulate all the connections and members.
Also carbon fiber varies soooooooooooooo much in properties that answering the carbon fiber questions is nigh-impossible.
See the above.
Take a engineering materials and machine design classes for further questions.
Menebrio
> GhostZ
09/06/2013 at 09:01 |
|
I would assume role cages are mostly for safety. It might be help-full to reduce flex if your front engine car has been modified to produce massive power (over stock form) or if you are going to be putting it sideways a lot. Also, it might be worth it if the car has been previously damaged.
Its a really good question and I hope you get some expert answers.
Meatstick62
> GhostZ
09/06/2013 at 09:01 |
|
This is a fantastic book on this topic:
Engineer to Win by Carroll Smith
!!! UNKNOWN CONTENT TYPE !!!
///M3 Track Car
> GhostZ
09/06/2013 at 09:07 |
|
I think you need to decide on the exact purpose of the car before you ask all these questions. You're heading off in a million different directions, so there will never be a right answer...
|
GhostZ
> ///M3 Track Car
09/06/2013 at 09:33 |
|
They're general questions about material strength. It doesn't matter what the car is used for (and I've specified a few points where I want to know) but the problem is that there isn't much research or information readily available about this type of stuff, so I wanted aggregate oppo advice.
|
GhostZ
> Arch Duke Maxyenko, Shit Talk Extraordinaire
09/06/2013 at 09:36 |
|
All of the questions were just to get people thinking about answers. I want general information, the questions are just a way to see if I can get (from a large number of replies) some solid, consistent facts.
I'm more concerned with race car applications and hand-built chassis though, not necessarily the pure hard material science of it. I want to try separating fact from fiction about chassis mods.
Good advice though.
|
Arch Duke Maxyenko, Shit Talk Extraordinaire
> GhostZ
09/06/2013 at 09:39 |
|
Well if you want to separate facts from fiction then your going to need heaps of materials data.
And seriously the shoe box experiment is the best for demonstrating chassis rigidity.
|
GhostZ
> Sparf
09/06/2013 at 09:53 |
|
My (pedestrian) knowledge is that there are 3 ways to improve stiffness:
1. welding components together
2. replacing heavy components with lighter and equally stiff/stiffer parts
3. adding bolt-on supports.
"Stiffness" does a few things. It improves the polar moment of inertia, allowing the car to transfer one motion (at the front during turn-in) to the rear faster (but only by a tiny amount). It also is supposed to improve accelleration, because the torque from the engine bends the body a certain amount, and the less yield the body has, the less power supposedly is wasted on it.
So I would "guess" (but with no facts, the whole point of this post), ignoring weight gains or losses: singular carbon fiber chassis > carbon fiber pieces > stitch welding panels together > fiberglass pieces > bolt-on carbon fiber reinforcement > welded reinforcement > bolt-on steel/aluminum reinforcement.
My scenario, as you would guess, is how to improve a S30Z chassis (similar to a GSL-SE) to handle more power. Supposedly spot-welded panels (which an old-school technique I know little about) with triangular welded-in reinforcement over key areas is the best way to go without dumping money on CF panels or adding too much weight. Put on a CF hatch, fenders, and hood, and you'd be talking serious weight loss and probably good enough to handle a lot of power. But again, I don't know enough facts to be able to back that claim up.
|
GhostZ
> Meatstick62
09/06/2013 at 10:02 |
|
I read "tune to win" a long time ago, I didn't know there were multiple books in the series! Awesome! I'll have to check this out.
|
Meatstick62
> GhostZ
09/06/2013 at 10:53 |
|
Yes, it is an awesome series. I have most of it on my bookshelf.