Build - 9 second drag truck #racegreen

[bgreen776]

I'm surprised, but it looks like I can get 1-3/4 x .095 4130 tubing up here for less than $7/foot. I wonder how light can a guy build a full size truck without spending big money on carbon fiber body panels and the like?

4500 lbs sounds fairly reasonable.

[jlibert]

If you're concerned about weight, you should be using 1-5/8 .083

[Hdhorton]

Sub'd

[bgreen776]

Originally Posted by jlibert

If you're concerned about weight, you should be using 1-5/8 .083

I am, but I'm also concerned about my safety, the trucks longevity, and stiffness. Once I have a design I'll do the calcs and see what the weight differences are. I'll likely end up using both, with some 1-1/4 .049 thrown in there in places.

Since there is no cert allowing a 4500 lb car into the sub 8.5 second zone, is there any reason to do a full tube chassis at this time?
(Other than so you can add ballast where you want it)

It looks like guys are getting down to 4500 lbs while still running stock frame from the back of the cab forward.

[AHall]

An 8.50 cage doesn't seem safe enough to go that speed @ 4500lbs.

[bgreen776]

No doubt. I cant believe they let me run 125 with a roll bar made to specs for cars.

[AHall]

I would suggest you build it as safely as you feel necessary. I added several more bars than needed. You can always build another race car. Much more difficult if you don't live through a high speed oops.

[lorendiesel5.9]

Originally Posted by lorendiesel5.9

*hash tags don't work on CompD
*you're building a race truck not your 401k
*there is no "saving" money
*buy someone else's and have more fun
*this list is stupid

Originally Posted by bgreen776

Wake up on the wrong side of the bed today?

Originally Posted by longhorn859

Originally Posted by Woosley

He's not to far off from reality.

Originally Posted by Shainer

I'd say he is smack dab in the middle of reality.

Originally Posted by bgreen776

*hash tags do work, sorta, gives people a common search term. Not a bad thing when trying to give back to your sponsors.

*I am doing both.

*trying to spend less money?

*those that can't or won't do it for themselves buy other people's headaches. Not my style. I like banging my head on walls I built. .

*^this list is really stupid.

I don't remember who pissed in my Wheaties but I think I'm hilarious. Just ask my friend Joey. He's imaginary but has awesome ideas.

[mudder500]

More bars better you r in these trucks. We over build our race buggies but also use lots chromoly where we can. If I crash at 100 plus.... I want best protection so I can c tomorrow!!

[bgreen776]

I have a back half offroad truck, fully boxed frame, and a substantial structure over the engine compartment, and a halo over the cab.

The first hot day you are rolling around with the windows down and you grab the top of the door/cab... you realize quickly how much a chassis will flex even one that has a fairly substantial roll cage.

An 8.50 cage wont offer nearly enough structural support for what I will want out of the chassis. I'll do what I need to, to satisfy the requirement, then build the rest of the chassis however makes the most sense to me, if that will get me through tech. That is my concern, if I build a 8.5+ rig, with a full tube chassis, or even back half truck, will tech flip out because it doesn't look like a SFI 25.5 chassis even though you can't have a 4500 lb 25.5 legal chassis?

Maybe a call to SFI is in order. I have read on Compd that they have expressed interest in a new spec for us heavier trucks.

[AHall]

A new 25.6 chassis rule is in the works.

[TheBac]

Have you talked to Michael Pliska about what he's found out while he's been building his truck? Might be apples-to-oranges, but he'd have insight that might be helpful. http://www.competitiondiesel.com/for...d.php?t=120983
Idaho Rob (Max'd Out) would be a good source of info, too.
After reading all these build threads over the years, I wonder if we should be using the safety specs for the next class (or two) higher up when building these trucks??

GLWB.

[bgreen776]

I had forgot about his thread, thank you for the tips.

Ahall: do you have some insight into 25.6?

[AHall]

Pm me if you have questions.

[jlibert]

Don't make me go to the other site for updates.

[bgreen776]

The entire truck is now gutted and stripped.

Next step is to start mocking up with pvc pipe, broom handles, whatever I can find in the shop to make define the general shape and size of the chassis. Then I'll start running strings of masking tape to represent individual tubes. Once I settle on a design I'll take a bunch of pictures and open them in Microsoft Paint where I can freely draw more lines. At some point here I will begin laying out the chassis in Bend Tech Assembly, paying close attention to the actual manufacturability of the design and the certification requirements of various sanctioning bodies. Then I can order tubing, build my chassis table and get to work!

I did call SFI and spoke to one of their tech guys. I'll be using 25.5, but in anticipation for 25.6, I will be using 1.75x.095 4130 for most structural bars.





This is just where my mind went last night as I was getting to know the Bend Tech SE software. Its not based on any reality, just wanted to start thinking about how the joints would relate to each other and whether or not they are possible for this application. I'll start over once I get my eyes on the 25.5 book.

[bgreen776]

Does anyone have any suggestions on drop spindles?


#racegreen

[malibu795]

Sub'd

[bgreen776]

People are always curious what books they should be reading when researching a project like this.

15 years ago when I was building the "Freak" I bought the Chassis Engineering book to learn the theory behind designing my own chassis and suspension, and every one of Carrol Smiths books to learn about everything else.

For Drag racers I might skip the Chassis Engineering book and Get Dave Morgans Door Slammers instead. The Carol Smith books can be a little redundant, so choose the one that seems to fit your needs the best and buy the other ones later if you so desire.

The Bickel Books are great. Everyone should have these even though they are expensive. Sometimes a picture is worth a thousand words, and these books are FILLED with pictures. I'll definitely buy more of the Jerry Bickel books as the project progresses. Thank you to Michael Pliska for convincing me to buy them.

[bgreen776]

This book is great for leaning how tubes should be joined, spliced, etc. Its full of invaluable illustrations and worth every penny for anyone that wants to do the best tube work possible.