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Who does Sand Drags

GRINCH

GRINCH

1/2 ton status
Joined
Jan 30, 2001
Posts
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Location
Helena, MT
Just getting back into racing again. However, I have learned a very valuable lesson. You cannot. I repeat CANNOT. build a all purpose rig and expect it to excel in all aspects.

I built the Grinch (67-72 Forum) as a multi purpose use rig. However, the competive side in me hates to lose. So I thought a mild Big block would be the ticket. I like to trail ride, Obstacle course and Sand Drag.

Questions coming in a minute!!!!

Specs on the Grinch.

1972 K5 Blazer, Full 6 point cage, 1 3/4 tube. (Not poop Pipe) NP241, Dana 60 Front, 14 SF rear, 36x13.50-16 IROKS, Eaton E-lockers front and rear. 4.88 Gears, 4L80E, Cad 500 with PJ3 fuel Injection. Racing Seats, Rock sliders, 1/4" Plate bumpers.

Total weight 6000#. Not a racing weight by any means.

We run 300' drags on courses that vary from true sand to broken up dirt.
My last runs were top speed of 49 MPH. I don't have my times with me right now and will post them later. I run in 4 low.

Without starting over how can I be more competitive in my class? I thought about shredding some easy weight before each race. I know I can drop about 800-1000# easily. Rock sliders are 1/4 wall tube double row and tied back to the frame, bumpers are made from 1/4 Plate. I think the top weighs 200-300.

I have also considered different tires. Mine are IROKs 36-13.50-16 on simulated beadlocks with Stauns.

What tire size and type (No Paddles) would work best? Right now with my gearing I cross the line at about 4500 RPM in 4 Low. If I drop down to say a 33" tire I will only pick up about 200 - 300 RPM. FYI. I Have my Trans programmed to lock the converter in WOT.

Discuss!!
 
I think the biggest thing is weight loss.

A smaller tire might help, but arent Caddys pretty low reving engines with huge torque down low? That might not make much of a gain for you if the thing revs past its peak power right away.
 
JDnobodi is into the sand drags, I only sand drag for fun, haven't actually went down the track being timed.

Are your tires the bias or radials, the bias ply are considerably lighter than the radials. I think the weight is killing you the most. Your suspension setup will make a difference too. Make sure you aren't wasting time wrapping up the springs or or squatting the suspension. Maybe get some caltracs to use at the sand drags if you are running leaf springs. Make sure you have a lot of droop in the front to maintain traction with weight transfer.

Torque converter can make a huge difference in an acceleration race, especially from a dead stop. You aren't locking the converter off the line with it floored are you? In a 300 ft race I would not lock the torque converter, maybe in 3rd gear in a 1/4 mile drag race, but not in a short sand drag. Try it both ways and see. The benefit of the 4L80E is you can get a higher stall converter nad still have the lockup for the street.

How much do the Stauns weigh? Rotating mass is the most important to eliminate.
 
79rustyk10 said:
I think the biggest thing is weight loss.

A smaller tire might help, but arent Caddys pretty low reving engines with huge torque down low? That might not make much of a gain for you if the thing revs past its peak power right away.
Click to expand...


I was thinking of a smaller tire. I have to buy some new tires anyway for the Cummins. So I thought about a 305/70-16 or a 285/75-16 (Around 32.5") You are correct on the low revving torque. Another mistake for the race portion.

folkenheath said:
Are your tires the bias or radials, the bias ply are considerably lighter than the radials. I think the weight is killing you the most. Your suspension setup will make a difference too. Make sure you aren't wasting time wrapping up the springs or or squatting the suspension. Maybe get some caltracs to use at the sand drags if you are running leaf springs. Make sure you have a lot of droop in the front to maintain traction with weight transfer.

Torque converter can make a huge difference in an acceleration race, especially from a dead stop. You aren't locking the converter off the line with it floored are you? In a 300 ft race I would not lock the torque converter, maybe in 3rd gear in a 1/4 mile drag race, but not in a short sand drag. Try it both ways and see. The benefit of the 4L80E is you can get a higher stall converter nad still have the lockup for the street.

How much do the Stauns weigh? Rotating mass is the most important to eliminate.
Click to expand...

I don't let the converter lock until 3rd or 4th. Why wouldn't letting the converter lock up be helpful toward the end of the track when you are almost hitting max RPM? I will turn off the WOT feature. I can also control it by MPH. Suspension is pretty stiff and I will have to watch a video or two to see if I get any axle wrap. I will look into the caltracs.

I thought about building a seperate racer next but I only race drags 5-6 times a year so not really worth it. Racing is still fun but you have to be able to win once in a while. In my class I'm not losing by much. Maybe a fender length at most.
 
OK, that makes more sense, I didn't think it woudl even lock in 1st or 2nd but since you said it was locked at WOT I thought the worst. Probbaly not a big difference in that case but I would still try it both ways and see what happens.

Maybe it's worth getting a seperate set of wheels/tires you can bolt on for the drags? As light as possible with good traction.

And any squat or wrap is energy wasted that could be propelling you forward.

Good luck man.

Have you tried runnning the IROKs backwards on the sand? They are directional and running them in reverse is more like a scoop than a digger.
 
I'd be shaving weight left and right, up and down, just about anywhere and everywhere I could. Especially on an off road rig only. Dump the body and put something smaller on it like an S-10 or equivalent. Just do anything you can to get rid of all that GM sheetmetal.

Next I would be playing with air pressure in the tires. Obviously lower is better for sand and I would also be checking into paddle tires. A high revving engine would also be suggested.

Out of curiousity, what is the largest paddle tire offered out on the market for such said duties?
 
For dedicated Sand Drags, sure Wes. For taking a multi-purpose rig to the Sand Drags 4 or 5 times a year I'd unbolt anything I could, like top, doors, tailgate, passenger seat, rear seat, hood ( :haha:)

I think paddles would take him out of 'Sportsman class'.

Iroks backwards might work good though!
 
thatK30guy said:
I'd be shaving weight left and right, up and down, just about anywhere and everywhere I could. Especially on an off road rig only. Dump the body and put something smaller on it like an S-10 or equivalent. Just do anything you can to get rid of all that GM sheetmetal.

Next I would be playing with air pressure in the tires. Obviously lower is better for sand and I would also be checking into paddle tires. A high revving engine would also be suggested.

Out of curiousity, what is the largest paddle tire offered out on the market for such said duties?
Click to expand...

you can get paddles from 31" to 38" tall.

theones on my k5 in my avatar are 35"
 
I was thinking about running some smaller Duratracs or KM2's since I could take them off my tow rig. They weigh 59# plus a lighter rim versus 75# (Includes the Staun) and a heavier rim.

I'm going to start with just the sliders,bumpers, second battery, rear seat, top and tailgate. I don't want to take to much off that won't go back on quickly. I trailer it to the race but Sat is usually drags and Sunday is obstacle course. I'm scared to obstacle it with the top off fearing it won't go back on. I think the top really holds these old 72's together.

Another track observation this weekend was a Jeep CJ7 with a mild 454. He basically had street tires although they were 35 12.50's. Hardly any tread and he hooked up well. The track was about 12-16 sandy fluff and drying out after the x class and Open cars went through with paddles. He beat a lot of the guys with good tires like MT/R's and DOT AG tires. Go figure. Maybe it was the weight ratio to motor. He didn't spin a whole lot.

I also only use the rear locker if that matters at all.
 
I've been playing on the sand since '78. For tires, unless you have massive power to weight, the balder (smoother) they are, the better.

Light rigs (ATV's, sand rails) need paddles, or heavier rigs with tons of power can use a paddle effectively.

So if you can find a wore out set of 33's, you might try that. On my Turbo Jeepster I ran worn out circle track tires that were 34" x 16" wide. I could go anywhere I wanted, climb the steepest hills, in 2wd.

Anyway, you may try some smoother tires. The next big one is weight. Drop 1000#'s, you will kick ass.
 
alexsdad said:
I've been playing on the sand since '78. For tires, unless you have massive power to weight, the balder (smoother) they are, the better.

Light rigs (ATV's, sand rails) need paddles, or heavier rigs with tons of power can use a paddle effectively.

So if you can find a wore out set of 33's, you might try that. On my Turbo Jeepster I ran worn out circle track tires that were 34" x 16" wide. I could go anywhere I wanted, climb the steepest hills, in 2wd.

Anyway, you may try some smoother tires. The next big one is weight. Drop 1000#'s, you will kick ass.
Click to expand...
forgot about that.
i guy i wheeled with in the sand once had a full bodied blazer running some leftover flat/circle track tires that were smooth but wide, and he did everything no problems.
 
Not racing, but in just goofying off at the dunes I could slow to a crawl on steep climbs, then accelerate to the top, while the CJ's or Early Bronco's with paddle tires just ran out of horsepower, bogged down, and spun (and couldn't make it to the top). And that was with me in 2wd, as I didn't have front tires the same height as what I was running in the rear, for the sand.


In the early 80's, I was taking my stock '69 Wagoneer everywhere using some big 30" tall passenger car tires. An LR78 passenger car radial, almost worn out. Dropped to 10 pounds, put it in 4wd, cruise around anywhere I want, any hill climb that I had the power for.

We sand dragged it once, we could beat vehicles that had 40-80 more horsepower, as long as they were running an aggressive tire of some kind.
 
Makes a stupid sort of sense, an aggressive tire digs down where a smooth tire might spin but doesn't dig down...
 
Exactly. No theory here, only lots of experience watching what works for others, and what didn't.

I did some video taping one year, and with aggressive tires, especially paddles, you can hear the motors bog as well, besides digging in. When the tires bite, it costs power, and wheel speed drops, causing more digging in. It was enlightening for me.

The smooth tread tires, never cost much power even if they too are digging in.

My apologies, the original post was asking for help, not my opinions on sand tires.
 
alexsdad said:
Exactly. No theory here, only lots of experience watching what works for others, and what didn't.

I did some video taping one year, and with aggressive tires, especially paddles, you can hear the motors bog as well, besides digging in. When the tires bite, it costs power, and wheel speed drops, causing more digging in. It was enlightening for me.

The smooth tread tires, never cost much power even if they too are digging in.

My apologies, the original post was asking for help, not my opinions on sand tires.
Click to expand...

I think it was helpful...
 
No apologies required. This is good information for all. Experience beats theory and bench racing every time.

My question would be how does this compare to the sand/dirt that most so called sand drag tracks use. It's not like it's dune sand. I would say more fine dirt than anything. The track I raced on last weekend was made from what the farmers call blow sand. They hauled it in off a couple of fields to build this track. Since it is lose and fine like sand I would think the tires would grip the same. Some of the tracks I have seen have been basically made from just running a disc through and mostly gravel and a firmer base.
 
Well here's another opinion of mine- you might want to watch the next race if you can, or see if you can find someone who's video taped the more stock rigs that were drag racing (youtube?). See whats working for rigs with good power and weigh the same as yours.

Did the aggressive tires spin and then take off? Or did the smooth tread just take off? My Jeepster with the huge circle track tires would just take right off, no drama, hardly any digging (although they would spin some, keeping rpms higher).

If you were "duning", climbing some hills, etc. we already know the answer. But for the surface at that track, I'm not sure if my experience is relevant.

As a racer (drag and sand), taking as much weight out as possible is a sure bet.

I'd like to see a video of your next race :popcorn:
 
Oh, also make sure your rear suspenion is planting the tires, and not allowing the vehicle to squat, which reduces the pressure on the tires.

Maximum downward pressure on those back tires, no matter which tire you use, will get you out of the hole the quickest.

I've seen guys run traction bars for racing, which try to lift the rear of the vehicle and planting the tires, then remove them for fourwheeling.
 
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