I'm part of the Chico State SAE Mini Baja Team. We're building a 5'X8' 10hp 2wd Go Kart basically, which we will use to compete against other schools in Utah next May. We're starting from scratch, probably making frame and roll cage out of 4130 for weight (1020 DOM is also a consideration), and using a Quad transmission (also considering centrifugal clutch) for speed. We're required to compete in a rock crawl, a hill climb, a 4hr endurance race, and a "drag race".
This year they added the rock crawling event, I was curious what you guys think are key engineering points to take into consideration for design, what would be a good quad tire to run, would four wheel brakes be a factor or would two be sufficient. We're all four wheelin' finatics, in our trucks, but most of us have limited rock crawling experience. Any feedback is appreciated.
Also, as of now it's all out of pocket, if anyone knows a good place to look in Nor Cal for sponsors, donations, or just events we could sell food at I would be greatful.

Thanks

John
VP Chico Team
jc248@mail.csuchico.edu

old pic @ www.csuchico.edu/sae/
We're in the process of expanding on this page, much more.

first rule of rock crawling. IFS SUCKS

now i am not saying to build a mini baja racer build for speed with a straight axle but that is what it will probally take to dominate the rock crawl part of your competition.

second item

low gears

for sponsors.

look up silly neck of silly fab works in chico. he is loaded and would love to sponsor you. :D

Thanks, you don't know how much I appreciate this camo.

Originally posted by jc248
Thanks, you don't know how much I appreciate this camo.

stick around for awhile. you will get more feedback than you know what to do with.

also i was kidding about sillyneck. yes he is a real person and he is a student at chico. he is also a experianced fabricator and rock crawler. he may be able to help you guys with your design. look him up.

way, ahead of you
already e/m him

Thanks again

I'm at UC Davis and we have Formula SAE (mini formula cars) that I'm going to get involved with... That's cool that you guys have Baja...

hey camo, where r u runnin out of, if you don't mind me asking

currently running out of my mind. :flipoff2:


atascadero ca :D

yeah, we tossed around the formula idea, but we're all a bunch offroaders up here, so we went with baja.
Good luck this year.

ya ever need anything up this way, don't hesitate to e/m me

cool, hey I see your part of the tin benders squad, heard about frostoberfest, thinking about getting a bunch of guys to go.
Maybe catch you there.

Ahhhh yes the RICH and famous 'neck de silly :D bawhahahah

sure John I think i can help. Looks like last years rig was pretty well designed. Bring me a portfolio of pics of what you had as well as the parameters of the project and we'll see if we can't figure something out. I can get you hooked up around town w/ different suppliers I know. Maybe even rustle up some people to sponsor you. Personally I don't have a dime to give but I would be glad to be a part of the effort/workforce if need be.

Does it have to be a 10 hp engine?

If not, put a engine from a GSXR 1000 in it, and just make it all chain driven. Would kick some serious ass.

I vote run the 10hp motor but run it off a 150 shot nos bottle :D no worries about gas tanks that way :D

Yes it has to be a 10hp Brigs.

Look at making some high clearance front arms. Spool the back, dual arms would be nice but always easily done. Make sure to have a high clearance frame so you have less to hang up on. It would be nice to have an atriculating rear axle but with how everything is setup I don't think it would be possible. So what I am thinking for our car is some kind of forced action in the rear to lift it up over the rocks. I think I can managed the fron IFS but if th rear would articluate it would help a ton.

As for tires we are running the IP Titan's. They seem to be a good tire. I would like something with more tread(aka swamper) but not real heavy. I think we are running a 21-22" tires and I would like to go bigger if we can, 25-27". Gearing on ours is around 10.5:1 and we might go as far as 12:1

As for the frame we are using 4130 as always. No you know all of our secrets. :D

Oh yeah I'm from SDSM&T underclass team.

Thanks guys, drawback though is we're not aloud to touch the engine, there's even Briggs specialists at the competition who can check who ever when ever. Only things we can do with stock 10hp briggs is have as much stock dia. fuel line as we want, and relocate the stock exhaust, but have to use stock muffler.

And Sillyneck, if you got some time you should drop in on Monday, @6pm in Langdon 122, I'll see what photos I can rustle up. Even if you can't show up I'll get the photos to you some how, we appreciate the help, if your a CSUC student, you can even join the team, if you want. Either way we are greatful for the help.

yes it has to be a 10 hp 305 briggs and Straton......... you are limited to like 3800 rpm... so you really don't get but like 6 hp...... but its fun... there was a thread about it a couple weeks ago if u search for it...... there's a hand ful of us from AUBURN on the board

Hey, weasel thanks, lookin forward to seeing your car in Utah

Good Luck

Originally posted by Sillyneck
I vote run the 10hp motor but run it off a 150 shot nos bottle :D no worries about gas tanks that way :D

Ha..... Its funny that you bring that up. A few years back we were tossing around the idea of turning the chassis into a big NOS tank. Nobody would ever know, well hopefully.

Originally posted by camo
first rule of rock crawling. IFS SUCKS

now i am not saying to build a mini baja racer build for speed with a straight axle but that is what it will probally take to dominate the rock crawl part of your competition.

second item

low gears

Yes the glitter pimp is on the money. Go with a rear solid axle swing arm style set up. So have you heard the Baja stories of years past, this came up on another thread. We have had good times with the Chico crew.

I forgot one thing....KISS.

Sounds like it may be your guys first time ot frist in awhile, so don't mess around with getting to complicated things. Get a solid, well built, simple car built and spend atleast 2 months beating the piss out of it. If you can get throught the entire event with out breaking you have a excellent car.

Yeah I know all the Chico guys and have seen the cooter girl pics, too bad none of the old guys want to participate, I got a bunch of real newbies on my hands, never done anything like this.

tried to post some pics, but there arent any good ones up.. I just joined up with the mini baja team at cal poly pomona... Our team did Utah Last year, this year it is Ohio!! Should be lots of fun.

Garrett

Sounds like how you are competing it woudl work better for you guys to have lower gears.. for us, higher gears will work alittle better, we are doing basically a tractor pull, top speed, hill climb, and the 4 hr endurance. Once again, have fun.

Originally posted by jc248
Only things we can do with stock 10hp briggs is have as much stock dia. fuel line as we want

Old outboard racing trick, maybe you already do it... make a cold can for the fuel system. Basically a big coil of steel fuel line in an insulated container filled with ice. For the high speed runs, it makes a noticeable difference.

Mark

Nope can't do that either since you have to use the stock tank.

Weasal has some good ideas. The big things to keep in mind, are that you don't want to design your car for just one event. That is the whole point of the competition, is to make it adaptable to all events. Solid rear axle is cool, but hard to make work with the limited constraints you have. Also, if you are only getting 6 hp out of your motor, you have something wrong. We dyno tested our year old motors(the first gen OHV), and got around 8 with them. This is after racing them for a year and beating on them testing. Build the car to the rules also. Don't try to skimp on anything. They will catch you. Other than that, design it simple and make it easy to change parts because you will break. It is like you have camo driving it all the time.:flipoff2:

Weasal, do you guys have any design ideas yet? I plan on stopping by when I get back to Rapid and see last years cars and see what is new. Later

Erin

i am also in mini baja for cal poly SLO. You clearly have not seen the rock coarse. It is WEAK AS FUCK. there is no crawling involved, just momentum. NO climbs just little rocks every where. goto their web page and watch the preview video of them running it with their car.


Hey camo does your glitter company want to sponsor the Cal Poly SLO mini baja team?

So Hick, you guys are running in the Midwest Competition. No Rock crawl for you guys, why aren't you running west?

Rock Crawl sucks, thats too bad I was really looking forward to something alittle more challenging than some of the past events. Thanks for all the input guys, I never expected this thread to reach 2 pages.

The east race requires you to make your vehicle float which causes a different approach

Originally posted by willymutt

Weasal, do you guys have any design ideas yet? I plan on stopping by when I get back to Rapid and see last years cars and see what is new. Later

Erin

Well we arn't sure if wee can use our old car that we built last year cuase of some of the rule changes. Our bends on the rear hoop are 6" and this year they have to be 5" max. We are thinking of using the same design as last year just fine tune it some more this year. Maybe a double reduction chain box, new/better CVT's, better rear racks, lighter upper arms, maybe some sort of force articlution in the rear, that can be disabled easily, diffrent gearing, diffrent tires. We have a good car just need to get the bugs worked out. Stop by sometime.

Originally posted by TRD


Hey camo does your glitter company want to sponsor the Cal Poly SLO mini baja team?

put together a proposal and come see me. D

You might want to consider 4 wheel drive. Any pebbles in a 2 wd go cart will be nothing more than wheel chocks.

Originally posted by FearMe
You might want to consider 4 wheel drive. Any pebbles in a 2 wd go cart will be nothing more than wheel chocks.

No way....... 2WD is the only way to go for this comp. 4WD will be too heavy and power loss will screw you. You will lose with 4WD. Oh did I mention that 4WD is not the way to go here.........ok I am done now.

Originally posted by jc248
So Hick, you guys are running in the Midwest Competition. No Rock crawl for you guys, why aren't you running west?

We are also doing west, so i am sure i will see you at compititions.

Also, does anyone have any ideas for a live axle rear engine buggy? I cant seem to think of anything that would work and be reliable. Plus the weight would be killer, and our weight distrubition sucks right now.. all in the rear, so we go butt down over jumps... but we are in the cad process right now on the new car.. so it sould all be good.

Garrett

Make a four link axle. There are several ways to go about it.

Mount the engine solid and have a four link axle. The problem here would be how to drive the axle. You could use a driveshaft or a cog belt. A chain wouldn't work cause I don't think it would twist enough.

Mount the engine to the axle so then entire thing moves, then you don't have to worry about how to drive it.

Originally posted by Weasel
maybe some sort of force articlution in the rear, that can be disabled easily

It's been years since I worked with a SAE competition car ... but not too much has changed.

The only place the IFS is poor is the rockcrawling (only 5% of the available points), and cranking the clearance up in the rear is easy with torsion bars, if designed to make a ride height adjustment.

KISS, trailing arms or swing axle with torsion bars that can have the spline nut pivoted. An active system is too complicated (unless you have hydraulics) but a simple hand lever and lock arm can be made adjustable for changes between events. Coilovers that can be relocated will accomplish the same, but not as fast. Take what you learn about suspension geometry and GC vs. roll center, at static and dynamic height, and apply it to excell in the points with an adjustable system.

Cutting brakes.

The rules may have changed to direct what you can get away with, so focus on the rules (read the rules, it's the same in every racing arena, so approach it the same as you will approach professional fabrication).

The best advice is build it early, and test it often (get the fun out of it). Break it, fix it, make it reliable. Endurance is 40% of the total points.

Make it quick: hillclimb, pulling and acceleration is 20% of the points.

Take notes and save them, including test runs, and note all changes with justification in the development (even the efforts that fail). Note every person you approach for funds, and log the effort.

Select a single team member to assemble the report. The points from the documentation were always a factor for the winners and they will spend considerable time collecting the notes and building the report. All those notes, even if they are not backed up with formal calculations for every change, make good footnotes and references (it's an example of the Engineering method, it's also 30% of the points).

You want the report to be assembled by a single team member so they can be eligible for other individual effort competitions.

The SoCal team members who write the report should also prepare for the SAE Southern Section Max Short design competition. This competition has a $$$ reward so it takes the sting out of the boring details of the documentation (incentive, incentive, ... or beer money -- your choice).

All this documentation and reading of the rules may seem a waste of effort, but it's where the winners focus the effort.

When you go to Utah (or the other event locations), photograph everything. Engineering does not occur in a vacuum (not in the professional arena).

Happy Trails!

Does anyone know if fuel coolers are allowed, I know we're only allowed stock dia. fuel lines, but can we run them into a fuel cooling unit?

Originally posted by camo


put together a proposal and come see me. D


Will do.

I did this comp in El Paso around 1995. We (UCSB) had the smaller 6hp Briggs.
Read the comp rules over and over.
Document how AND why you did everything.
Prove your suspension works in the real world and on paper.
Ditto on the drive train.
Be ready to sell this thing.
You’ll likely need to have a sales brochure, heck get a Marketing student to help out. It be good for him too.

Look at the types of comps you’ll be doing. We had a maneuverability test and it kicked our buns. A diff and cutting breaks would have saved us. We thought the rollers would work, but we didn’t have enough practice and they were not good in sand.

The four-hour event is all about reliability and speed. Bring spares, and test ahead of time. We broke a throttle cable and I ended up with it in my hand.

If you don’t have a maneuverability test, then go with a solid or spool or roller clutches (expensive). With a spool you can run a single rear break, which is plenty and cheap. Check out used kart stuff for the rear breaks. If you get last year’s tech, it’s almost free. :D Try the bulletin board www.ekartingnews.com I’m sure there are people on the board that will donate or help out. I you need a diff, then try hard to get a locking diff.

As for the hot tire, I don’t have a clue. Try the Quad websites. You’ll need to see the terrain or ask about it. On the hill climb, run the tires soft and bring a pump to blow them back up. Or run what is free. :)

Everyone had IFS and almost everyone had IRS. We had both and it kicked butt.

If you can keep last year’s buggy complete, then leave it and use it to race each other. You’ll at least want to beat last year’s car!

I loved this comp and I’m certain it helped me get my first job. Take lots of pictures of the project along the way and a few at the comp. I brought them to my interviews. If that doesn’t get the interviewer going, you probably don’t want to work there. :D
Note: don’t break out the pictures until they ask you about them, and they will if it’s on your resume.

If you have specific questions, email me. I’d be happy to look them over.

-Pete

Thanks Mel, I'll keep your name in mind if we hit any road blocks.