PaintballaXX

Messing around in solidworks. Mash up between a corvette power and what will be formula 1/indy inspired aero. The body panels are a poorly done mock up. Estimated weight of this current design with all components (not pictured) will be about 1500 pounds or less; thats including a ls1,3,7 and drivetrain. Likely around 1300 but I dont have everything modeled up in full detail. As far as the racing ive done, just karts. One unusual convention in my design: Im not using a porsche transaxel.
Oh, and anybody have dimensions and weight of the c5/c6 differential? Doesn't need to be to exacting for now.
(excuse the crappy pics, i was using paint to save my screen shots)
Took out the originals because there is no longer a point of wasting the bandwidth.

bb69

I like it. Let me guess, your plan is to mate a LS engine to a Corvette transaxle? What kind of suspension and brakes are you planning on? The reason I ask is that I don't think my car is anywhere close to 1300 pounds, and it's pretty similar to yours. I am using all C5 suspension and brakes and those components are pretty heavy for such a small car. I am also using a 5.3, which has an iron block. Figure another 80 pounds for that.




I've added some sheetmetal since this pic was taken. I figure my car weights somewhere between 2000-2400 pounds.

I can get more dimensions in a few days, but here is a rough shot of the trans and diff bolted together.




By the way, if you're looking for more information on building a car from scratch, check out locostusa.com/forums.

Ken

0Randy@DRM

Cool drawing! I would start removing bars in the chassis unless they are going to be very small in diameter or wall thickness. The main hoop is kinda scary, smaller packages are stronger, look at some more open wheel cars for some better designs.

I have been drawing a chassis at home with a piece of paper, ruler, and pen. Maybe it's time to step into the 21 century Well I kinda like doing things the old way first.

Randy

BrianCunningham

neat!

69427

Hey, Ken, glad to see some update info from you. Hadn't seen any of your posts in a while.

PaintballaXX

The bars are a relatively small thickness. I'm trying to gain chassis strength from geometry rather than material. I'm going to do a stress analysis on the frame tomorrow and the roll hoop will end up being a different shape and reinforced depending on how the frame is being strained. Maybe some supports will be removed if they are under stressed. The suspension will be custom made, its not to hard or expensive to do that. Also I get the advantage of creating the best suspension geometry for my car. It wont have the same instanteous roll center and stuff that a c5 or other production car would have.
bb69, what wall thickness have you used? Oh and thanks for the website, Ive been looking for a place like that. Try typing in custom made car or something along those lines and google will show you modded civics and whatnot.

PaintballaXX

bb69, do you have a build thread here? I noticed in 2005 you asked where to learn how to tig weld...wonder why Seems that project has been in the making for a while.

bb69

Here is the thread on this forum:
http://forums.corvetteforum.com/auto...track-car.html

Here is the thread on my own page:
http://www.3ballsracing.com/index.ph...id=875&catid=3

I wasn't the best at posting updates, and I also worked on the car in chunks.

All of my round tubing is .095" and the square/rectangular is .120". I wasn't planning on .120", but when I went to the metal shop, that was all they had in rectangular. I decided to change my design instead of having to special order all the steel.

I wish I could say that I did any TIG welding on this car, but I didn't. I did take the class, but I never bought the welder. Someday I will make it a priority and buy a nice Syncrowave.

I'd love to see what you come up with for a suspension. I was planning on designing/making my own, but I decided it would be better for me to focus on the chassis for this car. For the next one, I plan to design more of the suspension. However, I am also planning on using circle track components for the next one because they are strong, cheap, and very easy to come by.

EDIT: One more thing: I believe the C6 differential is different than the C5. They do not interchange, so you need to decide which one you want to use.

Good luck and keep the updates coming.
Ken

PaintballaXX

Man there is just so many obstacles to overcome trying to use a corvette transaxle that I decided to do as many others and use the Porsche g50 transaxle.
Also took the opportunity to start the basic "skeleton" of a frame.

Just as a reference to the size of this thing, the wheelbase is nearly the same as a vette. The suspension boxes arent set in stone btw, they can be modified in less than a minute to whatever size and distance apart Id like.

Now here is the thing: the g50 will allow me to have a exceedingly low polar moment. This should allow the car to transition quite well. But as I said, Ive never actually raced a full size automobile on the track at the limit. So what I'd like to ask is how you guys feel about a weight distribution that comes close to 60-40? Its hard to tell right now where this will end up, but it is quite rear-ward as of now to say the least. It seems like 60-40 is the lower limit as far as the designs I've seen.

bb69

If you've never driven a car at the limit on a track, that could actually help you. The reason I say that is the car you are designing will react very differently than a typical front engine, rear-wheel drive vehicle. It will transition quickly, both when you want it to and when you don't. Think snap oversteer. That doesn't have to be a bad thing; just something you have to be aware of and know when it's going to happen. Porsche has made it work with a more extreme distribution for decades.

Personally, I would think about making the car longer and adding some crush room in front of your legs. My car has a 118" wheelbase, and making transitions is not an issue. The performance of something like this compared to a normal car is so much higher to begin with, I would gladly give up some polar inertia to game some safety. This coming from a guy that already put his car into a tire wall.

Ken

subtlez28

That is awesome!

Have you scaled it though? 2400 seems like a lot. I'm hoping my stripped LS1 C4 comes in at under 3000. I would think things like body, glass, and other parts your car does not have would be more than 500 lbs...

bb69

I have not scaled it yet. I had a spreadsheet going trying to add up the component weights. I may be overstating it, but I'm trying to stay conservative until I get it weighed. I have a friend with scales, so I should get real numbers this year. I need to because I found out that I had one front coil-over mounted about half and inch different than the other. I'm hoping that help explains a problem I had locking up a front wheel a lot.

Ken

PaintballaXX

I dont think I will move the front wheels up more than a few inches, unless the weight distro improves enough in my mind. If anything I can always add a dedicated crash structure ahead and around parts of the frame.

0Randy@DRM

This maybe will give you some other ideas. We don't get to play with mid engine stuff often. But when we do it's been fun!!!

http://www.youtube.com/watch?v=t7zkX...eature=related

Randy

bb69

Come on now, you have to give us more than a little teaser. We need more information and pics/videos of that car.

Ken

PaintballaXX

I'd love to see that car driving. I noticed the driver seat is in the wrong spot lol. Guess it was just easier to design it as such because of the shifter?

0Randy@DRM

It's a McLaren elva about 1964-66. Powered by a Chevy V8. I'm a racer so power levels are unknown I know if you run too many RPM you get a fuel cloud above the carbs

Only video I could find It's not the same car but same type of chassis and engine. Leading the race....


http://images.google.com/images?hl=e...-8&sa=N&tab=wi


The orginal lug nuts had a torque spec of 5 foot pounds. That is right, 5 foot pounds, sitting inbetween two gas tanks, with a fire ball behide your head, going 170 ish. I think these did something like 190ish at Lemans.

Good stuff
Randy

PaintballaXX

Kinda took a while to get back to where I started. Not enough hours in the day. I need to read a book or two on suspension geometry, thats for sure. Some of my friends know a whole lot more than I do though, so I can get some outside consulting.




So far everything shown weighs about 950 pounds (without the 200 pound ballast I use to keep track of my "weigh-distro-with-driver.")
In case you guys are wondering, my axels/halfshafts are at less than a 11 degree angle and I'm told it is okay to go near 15 with this transmission.

Wren

You can add a pretty good bit to that for all of the welding, fasteners, and other crap that goes along with it.

Be prepared to devote an unreasonable portion of years of your life to a project like this.

If you are going to be changing around weight, track, wheelbase, and all of the other constraints that affect suspension design, then the Corvette parts may not be the best choice.

Here is our car. FB for SCCA club racing, fabricated in the shop you see behind the car, we ended up having to buy 2 cnc machines to get it done. GSXR1000 power. Track records at Savannah(1:04), Homestead(1:19), Sebring(2:03), and almost everywhere else we have run. Have not gone faster than 1:21 at Road Atlanta and 2:12 at Road America yet, but we have learned a lot since we last went both places. We hope to go 1:18 at Road Atlanta and 2:07 at Road America this year.



bare frame


completed car (Not that it is really completed as we have already changed a lot around on the car and we still have years of development ahead before we can even think about resting. We haven't even been to the wind tunnel yet.)

PaintballaXX

That is incredible. It reminds me of the student Formula SAE competition. Obviously that is a BIT different though, lol. That thing is just ridiculous. Do you guys have a chain driven differential? Or did you mount the engine longitudinally? Congrats on all those records. How much does your car weigh? If I had to guess it looks like something on the order of 600 pounds, plus or minus?
Edit: scratch that first question just say the first picture.

About that years ahead part. The development is the fun part! The day you guys finish will be a week before you think of another idea and put pen to paper for a little doodle!
Also, next time you in central of south Florida I would LOVE to see that thing.