I believe that as cars got more motor, they got longer wheelbases to make them more stable and "want" to go straighter off the line. I'll never know how they ran those AA/Fuel Altereds back in the day!!!
Well, I suppose if it was real straight and had a plug or two fouled it MIGHT go straight. I'm trying to visualize two yardsticks long....nope. I don't think launching is a problem, it's wide open in the lights bothers me. If it hits a snake turd it'll be a handfull. Lippy
Or as my buddy tells me, you'll have plenty of time to figure out what went wrong in intensive care. I agree, all kidding aside, I wouldn't make it shorter than a hundred either. That's pretty fast for a souped up six. If it was 90 in I'd drive it, but I wouldn't tell anyone else to. Lippy
Not that a HA/GR is NHRA legal but I believe the NHRA minimum WB is 90" my rear engine HA/GR is 120" WB, and the driver is pretty cramped. If I had the power to pull a direct drive I could probably subtract 10", then if I sat the driver position upright a bunch, I might get close to 100"
The shorter the WB the harder to drive. As stated eariler as HP increased so did WB. Had a Flathead Chasies Research dragster in mid sixties with 120 " WD drove well on rough strips.
92 is about the safe minimum. My senior Dragster is 96 runs straight no problems. !00 is very good. 120 to 125 is enuf for anything. After that it is my rail is longer then yours , sort of like the boat guys. However the longer a rail is the less suspension it needs. That appeals to some and is understandable.
From a physics perspective, the longer the wheelbase is, the more time it takes for it to get out of shape. Visualize a car with a 100 yard wheelbase, it would take a long time for it to get sideways. It really is that simple.
In the new NHRA rule book: SECTION 4A – SUPER PRO, PRO, SPORTSMAN Page 4.5 FRAME: 4 WHEELBASE (1/6/10) Minimum 85. Maximum wheelbase variation from left to right: 1 inch. Dragsters: 2 inches. Minimum front tread width: 26 inches on any dragster. I'd make it 90" and call it done. 90" is short... and when I came up with the rules for the HA/GR cars, the idea was formed around this car that I had seen at the Nostalgia Drags in Fremont back in the 80's... that had a T frame... I was 13-14 years old, and got it in my head that my brother and I were gonna build one. Here it is, and I am guessing it is around a 90" wheel base... Sam
If you want to find out how a short wheelbase car handles find a 90" VW dune buggy, that should tell you how long yours needs to be. Ask any woman longer is always better.
Your motor is always around 32 to 36. The fuel tank will eat up 8 to 10. The rad if you use one 4 , the front suspension about 10 the bellhousing another 10 to 12 at least . the trans 24 to 32. the diff is at least 8 from flange to centre. And then you need a place to sit and room got you feet . if you have a driveshaft there is another 8 to 12gone. Really when you cram it al together under 90 is pretty tough to do. I build my cars under 100 for the simple reason they will load in the back of my 1/2 ton or 3/4 ton box and no trailer was required. Now that i have a trailer under construction i feel free to stretch it a bit just for the right look if nothing else. Don
You'll be content with the Falcon 6 for a while, and then like any good hot rodder, you'll want a bigger motor to go quicker and faster. And then the short wheelbase will be a problem. Go out to 120'' and be done with it and cover your***** for future "upgrades".
-------------------------------------------- ["I'll never know how they ran those AA/Fuel Altereds back in the day!!!"] - How??? Mostly sideways ......and often as not, either bouncing off of, or up on top of the guarderail!!!!! Mart3406 ==============================
Shorter the WB = small polar moment of inertia. Longer WB = big polar moment of inertia. Polar moment of inertia determines how stable (or conversly how unstable) a vehicle is. Fly-by-wire aircraft have a tiny polar moment of inertia- they'd "swap ends" in a heartbeat, but use computers to provide continuous tiny corrective control inputs. Wow- I used my Avionics Engineering MS on the HAMB.
-------------------------- I think what somebody else here said about building the car with the wheelbase long enough to 'handle future power upgrades' is very relavent. Maybe a near-stock 170-inch Falcon 6 won't get you into any trouble with a super-swb, but if you're thinking of eventually running the car with a - quote - "propane-powered turbo 2.3L" 4-banger, you might be in for a big surprise power-wise. Upgrades, with big power increases come really easilly with these little engines! A couple of years ago I helped a buddy engineer and build an efi-turbo 2.3 for his OT "street" Pinto. Admittedly, being typical rodders and not being able to leave things alone - and upgrading and changing plans as deals and parts came along, the build got a little out of hand. What started out as a planned '250 or so hp' "street motor" rapidly turned into a little monster. We ended up with an engine that eventually dynod at 441rear wheel hp - at only 5500 rpm - along with nearly 480 ft./lbs. of torque! Power-wise, that's well into 'healthy small-block' or even 'mild big-block' V8 *race* engine territory! Don't sell those litte 2.3L 4-banger Ford 'Lima' motors short - especially once you start playing with turbos! . Mart3406 =======================================
Just for the record , not everyone subscribes to the bigger better deal. Here is how I thought through the Sr dragster deal i built. The engine is and will always be a slant six. The car is as it will always be. My job is to see what i can do with this. I have had it about 3 years or so now. I am still happy with it. Yes i will strive to go as fast as possible with what i have but it will always be what it is.That keeps the cost way down and the challenge high. It is much easier to think this way at the tail end of your racing days. Somehow you dont care when someone spends $75000 on a motor , $9000 on a trans and $50000 on a chassis to race in the same class you do for a $500 prize. It seems pointless. Now it is just fun. In fact i often just go and make a couple of passes on test n tune days, grab a burger and a pepsi and sit down with old friends around the cars and then load up and go home. i find that a wonderful way to spend an afternoon or evening. One younger racer told me a week ago, "anytime you are there I have a steak on the BBQ for you." I believe this is called the good life. Don Contented in Ameliasburgh
Back when the really short W.B. dragsters were popular, the slicks were hard rubber, narrow, and were "smokers". Put a modern, sticky slick on the SAME car, and the whole dynamic changes. My 120" W.B. FED, originally built in 64, liked to grab the sky, wheelie bars were an absolute must. It was'nt a problem at speed, but until the Glide was shifted into 2nd, and the car settled down, it could be an interesting ride. Mild SBC, trans-braked Glide with a 4500 stall converter, Olds/Pont rear with 4.10 gears, 29" M&H Racemasters 10" wide, it ran a best of 9.23/146MPH. Called the car "Short Ciruit". Build it longer, I would'nt go shorter that 110". I like the comment about having "plenty of time to think about where you went wrong while in Intensive Care". Butch/56sedandelivery.
78"? Whos going to drive it? A midget? My LSR sidecar is 108" and I barely fit. I'm trying to visualise a 78" wb, a straight six, and a driver. Its difficult. [/IMG]
I don't think so, T-man... that car was actually painted gray and was finished off pretty nicely. Sam
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