Garage Merch                Ron Pope Motorsports                California Custom Roadsters               

Long wheelbase vs short wheelbase

I had a '23 T named "Cardiac Arrest", with a 650hp blown 454bbc on a 109.5" wb. It didn't matter what you did, it was strictly point and shoot, and hoped you were pointing and shooting in the right direction, when you hit the pedel,ha!

In '77 I had a T named "Senility", with a radical 485hp 396bbc, with a 121" wb. What a difference in the drive down the road. I can actually relax every now and then.

My '27 T named "Lil Keg", which I sold to t-4-2 in michigan, had a blue-printed and balanced 350sbc, on a 110". He's done messed it up and installed a 425hp 383 Stroker, ha. It drives like a dream.

Just remember when driving a T, you get on it and it is going to get on you. Drive sensibly. Remember fellows, God gave men two heads and one brain. Drive with the one that has the brain!
 
I have 95 1/2" wheelbase, straight as a taught string, all the time, great on the freeway at any speed, steer with one finger at cruisin speeds, dirt roads are even fun, off road is also fun... But, any T's or other Hotrods that I have done work on, were all very evil handeling at full pedal.. People do not take the time, or spend the money to have their chassis setup correctly for HP... So drive carefully... :D
 
When I built my long car (144" w/b) I didn't know squat about setting up suspensions. I had quarter eliptic rear springs (half of a '55 rear spring I think) About 12" radius rods and a 3:08 rear gear. I could stand on it from a stop with hands off the wheel and she'd go straight as a string. I was over driving a 671 blower with .010 rotor clearance 20%. I guess if you have enough wheelbase it cures a bunch of evils.
 
one finger john said:
Here I go into a little theory. I have seen and have heard that on sprint cars, esp dirt cars, that with the torsion bars infront of and behind their respective axles the car thinks it has a longer wheelbase and has the qualities of a long w.b. car. To compensate for the the long w.b. feel and stability on a short dirt track (less than a 1/3 mi, almost continuous left turn) the actual turning agility is tuned by shortening the actual wheel base. That gives you long w.b. stability with short w.b. turning quickness.
I would like to know if that applies to 'suicide" front ends and rear suspensions with coil springs mounted either fore or aft of the rear axle or mounted directly over the axle.

Just thinking, John
Click to expand...

OK, nobody has really answered the original question... Sprint cars mount the torsion bars ahead of the front and behind the rear axles to make fine-tuning them more predictable. By mounting them in that manner, the torsion bars are further from the center of gravity (The chassis "thinks" it is longer) and can be a slightly softer rate. They therefore react less radically than if they were mounted between the axles and closer to the CG (The chassis "thinks" it is shorter) which would require a stiffer rate to do the same job. The stiffer rate spring (a torsion bar is just a spring that was never wound into a coil) mounted closer to the CG is more sensitive to minor adjustments and therefore less predictable.

On a street rod, where we don't have to make instant changes in chassis preloading for changing handling conditions, spring location is not as critical. We can use a spring that has a rate compatable to our application.:rolleyes:
 
I don't beileve it acts more gently, it is firmer, as is at the far corners of the chassis, the most leverage this way, for more control.. If it was inside the axles, this would make it much softer, like what you want on a T Bucket, RIDE not a race car suspension, like a go cart.. pretty solid... Buck Board affect.. :rolleyes:
 
Ted, you are correct. Maybe "gently" was a poor choice of words. I was looking for something that means "less radically". We are on the same page here, just not communicating it succinctly. I have re-edited it to be correct. Let me explain it a different way...

A spring (or torsion bar) mounted behind the rear axle or ahead of the front axle (outboard - further from the CG) will react more stiffly than that same spring mounted mounted ahead of the rear axle or behind the front axle (inboard - closer to the CG). Therefore, when we mount the springs farther away from the CG, we can use a softer spring to do the same job. In this case, minor adjustments to the spring, either in spring rate or height make, make very direct and predictable changes in ride stiffness or ride height. If the springs are mounted inboard, minor changes in spring rate or height may make more difference in ride stiffness or ride height, but they are also less predictable because of the leverage implied by the distance from the CG, length of suspension arms, etc.
 
Ted - I reread it all and I stand corrected.:o I have re-edited both posts and they should be correct now (I think). Would you believe I was testing you..?:lol::lol: I didn't think so...:) Sorry everybody for any confusion I may have caused. That's what I get for trying to hurry...
 
No problem, I do that at times it seems, get my tongue in the way of my brain, sometimes it is hard to catch up... hehe it's all fun, I just take it too seriously at times, because these types of rockets on wheels, can be deadly in the hands of a new commer... I always have to teach my customers how to drive their cars safely, as they move car lengths instead of feet, like a normal car, so one foot on the brake at all times when close to anything that is not moving in your direction, I always say.. hehe :)
 
Reading all this I found out you can ask 10 builders how to set your car up and get 10 right answers. OK here is my two cents for what its worth. The chassis for Becky came from a now defunct builder in SoCal, with a 100 inch wheelbase. It is a 4 bar setup front and rear, she goes down the road pretty straight. When you nail it off the line the backend jiggles around a little, then it settles in and takes off. It would be better with a lighter spring in the rear as it is to stiff. I'm running 31/15.5 Hoosiers in the back and 165's on the front. Turning is not a problem, in fact I have to watch that the tires don't hit the headlight bucket during a U-Turn. A lot of wheelbase questions can be answered by how do you want your profile to look.
 
Its a T bucket and you can do it however you want, just make it safe.

Most decisions on wheelbase, rideheight etc are determined by the look you are after, and how big you are and what you can fit into. My car sits high so I can have a flat floor for my big feet and a comfortable driving position. lower would look better imo, but I just might not fit comfortably with the trans tunnel taking away foot room.

If we all wanted the same stuff, I guess we would all build 32 roadsters wouldnt we?.;)

Theres a bucket here at the moment in the "classifieds" section that looks 100% perfect to me, but Im not too sure that I could fit into it. Pity that!
 
Ted Brown said:
I have tried and used a few 4 bar setups, they work great for cornering and comfort, but as far a quick out of the gate, they leave much to be desired, they squat down... :rolleyes:
Click to expand...



Hey Ted....I love the ole AA/FA's....if you remember they'de burn the hell outta the tires for about 300, the next 300 feet were back and forth keeping them between the rails and the last bit was holding the hell on and trying to keep from passing out from the G's!!!!! Hee, Hee...........:razz::razz::razz:
 
Ted Brown said:
When guys brought cars to me to fix, for doing just that, when finished, they were much quicker and did not act up, just like training a Dog.. hehe You now go in this here post HOLE and nowhere else on my lawn.. hehe :rolleyes:
Click to expand...

AAAAh....the good ole days......when the Swamp Rat was in a front engined digger.....I was over at the HAMB boards and they had a post on the old altered Pure Hell.......I used to love to watch that car race! Every-once-in-a-while........ it'd go up in smoke 3 or 4 places down the track, but what I really enjoyed was watching the burnouts where it looked like the car was just burning down. They don't put on shows like that anymore......shame.......
 
VegasBruce said:
Reading all this I found out you can ask 10 builders how to set your car up and get 10 right answers. OK here is my two cents for what its worth. The chassis for Becky came from a now defunct builder in SoCal, with a 100 inch wheelbase. It is a 4 bar setup front and rear, she goes down the road pretty straight. When you nail it off the line the backend jiggles around a little, then it settles in and takes off. It would be better with a lighter spring in the rear as it is to stiff. I'm running 31/15.5 Hoosiers in the back and 165's on the front. Turning is not a problem, in fact I have to watch that the tires don't hit the headlight bucket during a U-Turn. A lot of wheelbase questions can be answered by how do you want your profile to look.
Click to expand...

do you know who built your frame?
 
LumenAl said:
do you know who built your frame?
Click to expand...


A company called Specialty Cars, I think they are gone now. I haven't been able to find anything on them.
 
Sign me up for the AA/FA fan club too! I built one for a friend (Wes Jerde) back in the early 70's. He ran it one time and it scared the crap out of him. He sold it to a guy less the motor and he turned it into a bracket car. There is kind of a funny story connected with this car. I'll have to tell it when I have more time to type it. Very slow typist!
FA2.jpg


A buddy and I went up to Eddyville, Iowa for the Fuel Altered race last year. Funny cars with T-bucket, Fiat, and Bantam bodies just aren't the same as those early cars. Nanook and Rat Trap were there and we did get a little bit of the old time flavor. Danged sticky tires!
 
You must log in or register to reply here.

     Ron Pope Motorsports                Advertise with Us!     
Back
Top