Going to put my Bobbed Deuce on a Dynojet. Any guesses on the RWHP/RWTQ?

[HanksDeuce]

My buddy owns a business where he makes GM vehicles faster (Camaros/Corvettes/Diesel Trucks). He has an in-ground Dynojet chassis dynamometer. Looking at the dynojet website it lists the maximum axle weight at 3000 lbs. Right now I have the M105A2 bed off my deuce in preparation for painting the chassis. I weighed the bobber and she came in at 10,980 lbs the other day at the scrap metal recycler. Although the scrapper was closed today I will be heading there next Friday to get a rear axle weight. Do you guys think it'll be 3000 lbs or less the way she sits now? I might have to yank the 53" Michelins/recentered HEMTT wheels off and put on a set of NDTs/stock deuce wheels to shed some rear weight.

Since the factory tachometer uses a cable drive my buddy will use an optical inductive pickup from his dyno setup. He puts a piece of reflective tape on the crank pulley, and the optical sensor picks it up and converts it to RPM.

So, what kind of rear wheel horsepower & torque (RWHP/RWTQ) do you guys think she'll make with the injection pump turned up to 11-12psi and 1100F max EGT? I will dyno in 4th gear (1.00:1). I really wish I would have put it on the dyno with the IP at the stock fuel setting. Oh well.

I guess the stock figures (134 HP/330 TQ) increased a little from the added fuel (let's say 160 HP/430 TQ). Subtract 18% or so for drivetrain losses, water pump, compressor, alternator, planets out of alignment, being married, high taxes, fiscal cliff, and...

My guess:
105 RWHP
305 RWTQ

Oh, and I'll have video of the whole thing.

 

[patracy]

You'll be over 3K lbs on the rear axle.

You probably would see a little better torque than you listed. But I doubt much more over the HP you gave.

 

[m-35tom]

120 HP and 231 ft lbs, just a guess, let us know. you going to test it up to 2800 rpm?

 

[HanksDeuce]

I didn't get a chance to weigh at the CAT scales, and the scrap yard was closed. If the rear axle weighs below 3000 lbs I will dyno next weekend and take her to 2600 rpm.

 

[PsycoBob]

Single 9.00-20's on the rear might get you under the limit. I'm not sure what road speed Dyno's test at, but single NDT's in first gear might have traction issues.

You can try calling Dynojet & ask them if you can push the weight limit a bit "Just This One Time." Worst they'll do is tell you is it's too dang heavy.

 

[HanksDeuce]

Well, patracy was right. She is 480 lbs overweight on the rear axle for the dyno roller. I put the center of the deuce on the line between the front scale and the rear scale. Maybe I should move the rear axle more towards the front scale (edge of the rear scale)? I didn't pay attention much in Statics class. I live by the philosophy if it moves throw more concrete on it.

I'm going to remove my rear civvy hitch and bumperettes. By the time I drive back to the CAT scale I should have less diesel. Each 53" wheel/tire combination is ~550 lbs. I do not know how much a stock deuce NDT wheel/tire weigh. Is this possible or should I pass on trying to determine these numbers?

 

[DAS]

Jack under frame in front of rollers to remove some weight.....tie it down good...be carefull...just a thought.....DAS

 

[patracy]

Well, patracy was right. She is 480 lbs overweight on the rear axle for the dyno roller. I put the center of the deuce on the line between the front scale and the rear scale. Maybe I should move the rear axle more towards the front scale (edge of the rear scale)? I didn't pay attention much in Statics class. I live by the philosophy if it moves throw more concrete on it.

I'm going to remove my rear civvy hitch and bumperettes. By the time I drive back to the CAT scale I should have less diesel. Each 53" wheel/tire combination is ~550 lbs. I do not know how much a stock deuce NDT wheel/tire weigh. Is this possible or should I pass on trying to determine these numbers?

Moving down to a single 9.00x20 should save at least 500lbs on the rear axle, probably more actually. For example a 12.5" XL tire weighs 98lbs. Your 53" tire weighs 397lbs.

Jack under frame in front of rollers to remove some weight.....tie it down good...be carefull...just a thought.....DAS

Doubt that'd fly with the dyno shop. The truck has to "self align" on the rollers. Putting it on stand could cause misalignment and bad things happen...

 

[shenkmen]

Moving down to a single 9.00x20 should save at least 500lbs on the rear axle, probably more actually. For example a 12.5" XL tire weighs 98lbs. Your 53" tire weighs 397lbs.

Per the thread below a 9-20 tire on a deuce rim is 165 lbs. Without factoring the weight of your HEMTT rims that would be a difference of 467 lbs. Pretty close.

http://www.steelsoldiers.com/showthread.php?27663-Weight-of-Deuce-parts

 

[HanksDeuce]

Well, I initiated project Lard Butt. I removed the civvy hitch assembly, pintle hitch, pintle backing plate, rear cross member, old rear bump stops, and a bunch of big Grade 8 bolts. Maybe between this weight shedding as well as a lighter load of diesel fuel tomorrow I will be closer to that 3k mark on the rear axle alone. If not, I guess I'll swap the rims/tires off both my M105A2 and M149A2. That'll be fun for sure. NOT.

 

[welldigger]

Well, I initiated project Lard Butt. I removed the civvy hitch assembly, pintle hitch, pintle backing plate, rear cross member, old rear bump stops, and a bunch of big Grade 8 bolts. Maybe between this weight shedding as well as a lighter load of diesel fuel tomorrow I will be closer to that 3k mark on the rear axle alone. If not, I guess I'll swap the rims/tires off both my M105A2 and M149A2. That'll be fun for sure. NOT.

But totally worth having real concrete data to work with.

 

[HanksDeuce]

Well, it wasn't meant to be at the moment. I got her down to 3200 lbs on the rear axle. At the moment I refuse to swap the 53's. Sorry to let you guys down. Painting the deuce is more important this week.

 

[Danger Ranger]

I hope you go and do it sometime. I would like to see your results.
You should also, I think, swap the 53s for the small tires and then you can paint it with those on. More room the get the paint gun in there, and less to deal with. I think a couple hundred pounds wouldn't matter that much for one run.