short vs longer wheelbase feedback

[Dragsinger]

Racers,

When I built the original Super 10 it was a standard cab, short bed, 108" wheelbase. It worked will and I enjoyed the truck. I am considering building another, the thing is the 108" short trucks are becoming had to find in a clean, straight core. [note, the Super 10 was, at times, a bumper dragger]

The extended cabs are easier to find in good condition, they are 122" wheelbase.

So, my question, how would the 122" wheelbase work? Would it be a consistent runner, a capable winner? [of course, would be less prone to wheel stand, but it that a good thing?]

And I am planning this to be my personal bracket racer with either a small block or LS engine, maybe an aluminum block LS3 package. The power will be 650 - 700 range.

Let me hear y'all feedback about short vs long wheelbase.

[turbo camino]

One thing to consider is driveshaft length. 122" would probably not be happy with a one piece shaft (around 68-70" long?) and any kind of trap speed, and two piece shafts are a pain to deal with.

[Dragsinger]

You have a valid point. The pro stock trucks of that body style most likely had the engine set back several inches plus they had the funds for expensive driveshafts.

After a time of pondering, I do not think the long wheelbase is a good idea.

[Dylan Wilson]

Yall make a good point, in my dads ex prostock s-10 the engine was set very far back, and the driveshaft length was a part in that, though im not to sure personally the cons or the pros of the longer driveshaft, what i do know is that it will make a much more repeatable and predictable car, as well as a more stable car. 122 wheel base is pretty overkill for a door car, and 108 is not really on the too short side of things either. You can expect for the wheelstands to be much more responsive to weight and launch rpm, and the 60 foot to slow down. In the end the s10 platform has proven to be a amazing bracket platform with plenty of winners to show for it, either way you go the car can be highly competitive.

[turbo camino]

critical speed

[RCJ]

In the world of 60s chevy trucks it is common to take a long wheelbase and cut the Frame and bed down to a short wheelbase

[Zex4g63]

Critical speed was mentioned. Do the math. I found out the hard way. Broke a TH350 in half.

[Tom68]

Shorter is lighter.

[Rick!]

Folks have already BTDT.
https://www.yellowbullet.com/threads/s1 ... ft.123994/
Find a real good driveshaft shop that has S10 experience.
My calcs show that at 70", carbon fiber may be the only suitable material for the shaft. Steel or aluminum are only good to about 5900 RPM.
Fundamentally, the critical speed of the shaft is proportional to square root of its length cubed and the square root of the ratio of stiffness to mass.
The tables/charts at MW and PST and the Wallace calculator are different and are using different constants for how the "beam" is supported but they give a decent idea of where you might be at risk.

[Tom68]

Put a two piece in my 12" wheelbase Ozzy 1 tonner, had 2 critical speed failures in Chev powered HK Holden sedans, 140 mph tail shaft failures will wake you up.

[Tom68]

120" wheel base that is.