MyE28.com

Will do. Time to draw

Right, here's what I've come up with. I'll probably turn some of the curved pieces (like the ones going to the strut towers) into straight segments to save time and money.

It came!!!!!





For the m30. Whether I buy a b35 or stick with the b34 has yet to be decided. Either one will be redone entirely so I'm not sure if it matters what I start with.

Update: Finishing up frame design and hopefully going to buy metal this weekend or the next. After much consideration I realized it would be most beneficial to outsourse the welding to a professional for a variety of reasons. First, the cost to benefit ratio seems in favor of paying a proffesional welder the amount it would take to buy a decent welder itself. Second, the fact that I am not an experienced welder means it wouldn't be smart for me to practice on something that I would ultimately be trusting my life with. Third, the smaller amount of time it would take for a proffessional to weld the frame would give me more time to work on assembling the car itself.

Alright, time for another update. I've been working on the frame design and have finished the floor. It will be lowered three inches below the main beams by sypporting tubing and triangulation for support. Here is a picture of the proposed design.

I will insert the picture into the post later but the school server won't let me use the normal website.

http://s1113.photobucket.com/albums/k51 ... rframe.jpg

sbeckman7 wrote: I will insert the picture into the post later but the school server won't let me use the normal website.

You know you can just type out [img]and[/img] instead of pressing the buttons, right?

It's looking better. What's the reason for the open rectangle in the center of the car?

I might make those rear diagonals into and X instead of a /. That would add more rigidity as well as additional protection in case of a side impact into a tire wall or another car.

tsmall07 wrote:

sbeckman7 wrote: I will insert the picture into the post later but the school server won't let me use the normal website.

You know you can just type out [img]and[/img] instead of pressing the buttons, right?

It's looking better. What's the reason for the open rectangle in the center of the car?

I might make those rear diagonals into and X instead of a /. That would add more rigidity as well as additional protection in case of a side impact into a tire wall or another car.

Yeah, even with the image functions it wouldnt post at school The big space in the frontish area is for the engine because the oil pan drops below, and I'll probably make a skid plate for it too. Good idea on the X's though, and glad you like it!

sbeckman7 wrote:
The big space in the frontish area is for the engine because the oil pan drops below,

I was talking about the long, skinny rectangle at the back of the car.

tsmall07 wrote:

sbeckman7 wrote: I will insert the picture into the post later but the school server won't let me use the normal website.

You know you can just type out [img]and[/img] instead of pressing the buttons, right?

It's looking better. What's the reason for the open rectangle in the center of the car?

I might make those rear diagonals into and X instead of a /. That would add more rigidity as well as additional protection in case of a side impact into a tire wall or another car.

Agree on the rear long diagonals being Xs. The center rectangle is the driveshaft/trans tunnel, no? Presumably that will be strengthened by having vertical walls and tying into the structure from the top somehow.

-tammer

I was thinking thans tunnel, too, but it looks like the f/r bars that make the rectangle look like they are at the same level as everything else. I would make sense if they were bent up to make a tunnel.

You can build an effective tunnel with square tubing if you don't think you can do the bends with the round. Just make sure it's essentially a trapezoid with no bottom.

Since this is just the drawing of the very bottom level of the frame I have not included the rest of the transmission inner, but yeah that's what it is. I will definitely build it like you guys suggested.

The cockpit:



...the driver will not enjoy 65% of the room in the real thing.

A problem I encountered: I will have to modify the beams to accommodate mounting points for the control arms.





In other news, I finished the drawing for the floor. Ill try to upload a picture later today

The finished drawing:



The not-finished-but-drawn-to-scale drawing:

sbeckman7 wrote:The finished drawing:



The not-finished-but-drawn-to-scale drawing:

Why do you have the frame cross members mounted below the longitudinal rails?

the floor needs to be 3" lower than the rails

sbeckman7 wrote:the floor needs to be 3" lower than the rails

Why? That seems odd to me. If it were me, I would put a drop in the frame itself @ the firewall and keep all the bracing in approximately the same plane as the frame. Then, take the frame back up in front of the rear suspension. That would also make it easier to have a flat bottom, which is better for aerodynamics.

tsmall07 wrote:

sbeckman7 wrote:the floor needs to be 3" lower than the rails

Why? That seems odd to me. If it were me, I would put a drop in the frame itself @ the firewall and keep all the bracing in approximately the same plane as the frame. Then, take the frame back up in front of the rear suspension. That would also make it easier to have a flat bottom, which is better for aerodynamics.

This, which also allows you to weld the bracing inside the frame around the full perimeter of the brace tubes.

-tammer

Hmm. The way I have it makes more sense to me because it would be difficult to drop only part of the frame and still have it bolt up in the same place. It also seems like it would make the floor more uneven, not flatter. I think I would end up sitting lower than the pedal box.

If you went with what we're saying, your frame profile would look like this:


I've never seen a vehicle structure, custom or otherwise, that looks like the profile you've drawn above.

sbeckman7 wrote: It also seems like it would make the floor more uneven, not flatter. I think I would end up sitting lower than the pedal box.

It would allow for a flat bottom, or bellypan. The underside of the car being flat is better for aerodynamics. I don't understand why this would change your seating position. You're building the car. Put the seat and pedals at whatever height you want. Frame configuration isn't really a factor here.

tsmall07 wrote:If you went with what we're saying, your frame profile would look like this:


I've never seen a vehicle structure, custom or otherwise, that looks like the profile you've drawn above.

sbeckman7 wrote: It also seems like it would make the floor more uneven, not flatter. I think I would end up sitting lower than the pedal box.

It would allow for a flat bottom, or bellypan. The underside of the car being flat is better for aerodynamics. I don't understand why this would change your seating position. You're building the car. Put the seat and pedals at whatever height you want. Frame configuration isn't really a factor here.

Right, I get what you guys are saying. I just thought it would be worth more trouble than it's worth (although frankly I wouldn't know). If I went with my design, the floorpan would have the same underbody characteristics as the front half of your drawing; it wouldn't come back up before the rear subframe. If it would make sense to redo the main beams to the than I guess a small setback is worth it for added simplicity and strength. If I'm being stubborn it's because I'm told to redo the one thing that I have accomplished

sbeckman7 wrote: If I'm being stubborn it's because I'm told to redo the one thing that I have accomplished

Welcome to the world of custom fabrication. Get used to it! You won't have to completely redo it. Just cut and weld in some diagonals. Simple, right?

We're not trying to design your car for you. Build it the way you think it should be a learn from it. It's easy to sit back in my arm chair and tell you how I would build it. I'm not doing it, though, you are!

Alright, simple enough. So here's a question: would I only lower the part of the two beams that run parallel to one another?

sbeckman7 wrote:Alright, simple enough. So here's a question: would I only lower the part of the two beams that run parallel to one another?

By "beams" do you mean "frame rails"?

start the drop in the frame before (towards the front of) the two diagonals that are not parallel. This looks like it would be just behind your engine mounts. You want all of your bracing to come into the frame rail, not below it. I think you will thank yourself later when you make the trans cross member, as well. Have you measured the height difference between the engine and trans mounts?

Now I see what you're saying. This looks like it will also help with mounting the control arms. As for finding the heights between engine and tranny mounts, I have yet to do that. I guess I'd either have to bolt the two together and look at it that way or get measurements off of a complete e28.

Do you think it would be wise to redo the frame rails after the top half of the frame (the stuff in progress on the second drawing) is completed? I'm thinking that way it will have more structure and be less likely to deform. Since the mounting points are still the same, it would only mean that I would have to wait to build the floor.

I suppose you can wait until the rest is done, but I'd just weld some temporary supports in while the cutting/rewelding is going on.

Word of advice for the future:
Never fully weld anything until you sure SURE that it won't have to move again. I would get your whole frame system together (with engine, trans, and diff mounts in place) with heavy tacks before you finish weld anything. Of course, you have to pay attention to accessibility with this method as you move forward.

sounds good! And so a new direction begins...


A few quick little facts for everyone:

1. If this car weighs 1600lbs, a reasonable estimate, the stock 180 hp motor will give me 225hp/ton. My dream fully reworked 320+hp magical creation of Paul Burke would yield roughly 400hp/ton. Either way looks promising.

2. I emailed CARA Charities, an organization based in indianapolis which supports youth involvement in motorsports and driving programs, a proposal for a sponsorship. A call to their office this morning informed me that my email is currently being looked over. Fingers crossed.

3. I got into my first choice US college, IUPUI with the maximum academic scholarship! It's a branch of Purdue University located in Indianapolis (close to the CARA headquarters actually) and is the location of my future Motorsport Engineering School of Technology. I have reasons to be happy

4. Happy holidays/new years to everyone on here!

Sounds like you're headed in the right direction.
Congratulations.

And, here's wishing you your wishes granted in 2011.

So I decided to just jump into lowering the frame rails after all. Made two of the four pieces today, pics below. I'll eventually cut off the excess metal created from cutting at an angle and weld them shut. The 3 inch drop is within a 3 inch length so a 45 deg. angle did the trick and the pieces turned out very accurate. As to my problem regarding the control arm mounting points, I've outlined the proposed cutting area on the inside of the main frame to raise the arm to the proper height. It seems like a lot of metal to remove at a place as structural as this, but the other side of the rectangular pipe will need much less material removed due to the angle at which it mounts.

As it sits now:



Location of drop point:



Proposed cutting area: (sorry bout the picture)

I just realized what is wrong, the ride height is too low. This will seriously mess with your suspension geometry.