Another question on attaching the front axle.

[grapro]

I was reading to the regulations and could not find anything on attaching my front axle. my kit has a 2 1/2" saddle which is to be welded to the front bars. I found some stuff on the web  from the hamb and it looks like it makes sense.
 Quote"
At the point where the end of the frame rails meet the top centerline of the front axle it should be 2.25-2.5" wide so that you have material encompassing 180* of the axle half tube mount and heat the ends and tap them down (taper) to finish welding. If you try and fit the tubes smaller (1.75")your fit will be very long and require a whole bunch of welding whereas with going wider you may only have 10-11 inches instead of 20-22 inches. Lots of tacks and start in the back where the rails first meet and weld towards the front.
________________________________________
my front bars are 1.50" and it will be around 8" of the two bisecting, is this strong enough?

Also I was wondering and discussing with my buddy who is also building a fed, is a 200" inch fed much more stable than a 180" fed. does 20" really make that much of a difference. 

[dreracecar]

I wrote that

My car is 193" only because I was to cheap to buy 4 sticks of 1 1/4 moly to make it 200", cut 2 sticks in half and where they came together- that was my wheelbase.You can see how much purchase area the framerails have on the torsion tube.  Wheelbase stability is a matter of how far the rear can swing out and still recover. Naturaly the shorter the degree will be less before the  driver senses it and reacts, the longer the wheelbase the angle will be greater before driver reaction. A car going straight down the track, it make no difference what the wheelbase is. Now here is the rub, the shorter the wheelbase the wider the front axle. A narrow front track on a short car the greater the tipping motion is and if one widends the track in front the width acts as a outriger to keep the car from tipping.

[janjon]

I'm writing not because I'm an expert, but because I find the question interesting. Seems to me that increased wheelbase would be more beneficial from a standpoint of resisting the car's ability to fling the front end about, (both side-to-side and upward, with the rear tires' traction being essentially equal) rather than helping in a situation where the rear tires are lit up to whatever extent and the car's going sideways. The further out the weight of the front end is, the harder it is to swing it out of whack, the more likely the front tires are to stay aimed downtrack and not at the wall, and on or near the ground and not aimed at the moon. I think the degreed engineers call this "polar moment of inertia" or something like that.
 So I think that if you wanted to simulate 20" increased wheelbase, you could essentially do it by moving or adding some amount of weight to the front.
 As far as front track width, I've looked at the narrow tracks on some cars and thought that they might as well have been tricycles, but like DRE said about wheelbase being irrelevant as long as the car's going straight, I guess the same applies. If you're in a situation where you depend on an outrigger effect, you should have been out of it sooner...

[Dolmetsch]

I really think wheelbase is like 2 foot boat fever. I run a 96 inch wheelbase car and it goes as straight as an arrow. 200inches? At this point in my life I probably couldn't see the front wheels. I think it is more about personal preference. I find no ill effects at all from a short wheelbase. Lots of times an idea is perceived and expounded upon but often not based on any actual experience. I dont think the funny car guys find it a problem nor even do the tuner guys who are typically running ridiculous times on NOS and boost in 90 something inch wheelbases. However would my car look better if it was longer. Probably. I built it like this originally so it would fit in the back of my pickup truck. Now entering its 8 th year of competition I would change nothing. Runs like it was on rails. I had an old RED shoe(his car was a 225 incher) drive it two years ago just for fun and he said he was amazed at how stable it was. Point and shoot. No correction required. Mine also has Ackerman and only 3 1/2 degrees pos caster. The Ackerman is for the pits and turning into the lanes and sure saves front tires. It has zip to do with going straight but takes only a couple of minutes in a build do properly so I figured why not. 
Axle attachment it by a single 1/4 eliphtic spring dead centre in the in house made front axle. Idea was this leaves the rear to plant themselves without influence from the front axle. Of course in a long car that would not be an issue anyway .
Don