Ok, as some of you know, I am in the process of building a 4rotor (23A- two 12A's), n/a, and sprayed, to go to Bonneville to attempt for the rotary land speed record of 264mph.


My worry of the week this week is suspension.


It's going to be backhalved, maybe tubbed, so I'm looking to see if airbags would be a viable option, to just drop the car almost directly on the salt.


I reckon you suspension gurus have mixed opinions about airbags, so please, let them fly.

I'd ideally like to keep the bottom of the car about an inch and a half off the ground. If lowering springs/coilovers are a better alternative, let me know.


Thanks for the support, y'all.



*originally posted in suspension forum, but no replies*

 

Couldnt help ya, but good luck

Where you gonan get that crank at?

 

You won't be tubbed. You must run their special tires at Bonneville - they are quite thin and should have no problems fitting in the wheelwells as they're about the same width as stock tires.

I say use regular springs and just load as much weight as possible into the car to get it down. Salt cars like to be heavy, it keeps 'em on the ground and helps traction.

 

Yeah racing beat learned that lession once, when there car tried to be a , well hummm , an airplane

 

Salt has about as much traction as wet snow on ice. Tirespin is possible at practically any speed, especially when you consider that the surface is imperfect (bumps n stuff). Lots o' people build FWD cars for LSR attempts because they won't attempt to swap ends when the tires spin at high speeds.

Unless you want to build a rear spoiler 3 feet behind the rear bumper, kinda like a Porsche 935 "Moby Dick"

 

i'm sorry. i'm picturing this bonneville 4rotor on 3 wheels, front end bouncing. zzzzzzzzttt, zzzzzzztttttt.

 

Haha, I thought you meant you were "bagging" the project, as in giving up...lol.

~T.J.

 

yea, thats what i thought too.. scared me for a sec.. keep it up and dont let anyhtign stop you w000t!

 

That's quite a quality German-engineered Porsche right there

 

A large rear spoiler for downforce would keep top speed down, which is why the McLaren F1 (street version) or the new Ferrari F60 doesnt have one. Racing Beat's first FD took to the air then they came "back In Black" adding a large rear spoiler to it, beating the record set by the FC only by a few MPH, even though it had more than 400 HP extra.

 

have you considered making a full underbody tray?? that would helop the car create more downforce and also clean up the slipstream. If you make one make it like 3 pieces and ill buy one from you.

 

wanna buy the belly after I'm done with it?


I was planning on a full belly pan, that I could remove with Dzus Fasteners for when the "Bonneville" parts are in the trailer. Certain things (rims/tires, belly pan, 1-pc front fascia, etc.) are gonna be for Bonneville ONLY, and consequently, are not for the street.


Also, I had considered using a widebody kit, or even a subtle spoiler (and I still may...) to help get that extra downforce... however, they generate a LOT of downforce...and for track racing/autoX/highway/whatever, it'd be GREAT. But too much downforce becomes drag. Drag = lower speeds. Lower speeds = no record. No record = pointless project. See where I'm going with this?


I have some engineering friends that are using my car as their senior thesis in engineering and aerodynamics.... provided the aerodynamics of the car are at least completely and accurately computed on paper, and put through every test imagineable, they get their degrees. When friends owe you HUGE favors, and the only way for them to graduate with honors is to get an A on their thesis, you'd be surprised how hard they work to repay a debt. :bigthumb

 

adjustable spoiler?

 

hard tp picture a full belly pan functioning with a live axle, and anything less would be almost pointless (though a full engine bay belly tray would be great on a track, I fear one on the flats, if improperly executed, could create the world's fastest salt scooper)

 

My original idea for the belly pan was to stop right before the rear axle, then a diffuser of some sort after the axle.


However, I had also not thought about bagging it. by bagging the car and bringing the axle farther up into the chassis, and on a near-pristine surface like the salt-flats, would it be a better idea to just get a piece of sheet metal and run it the entire length?


The "segmented" belly pan was designed to have the layers overlap each other, as to prevent the "plow" effect. Here's a sketch of what I *kinda* had in mind.

Be aware... MS Paint strikes again!

 

Airbags are great. I have a mazda b2000 thats bagged.
If ya know what your doing, go with the airbags.