Best test of power?

[Gary - K7GLD]

What method do you consider most accurate and practical in determining useful power in a truck?

 

[BCFAST]

I vote dyno

Although a 7% grade is a good test of a puller's ability, you did say "useful"... and the dyno will show you WHERE you are making power and where not. Drags and pulls have too many variables (ie. traction).

 

[LSMITH]

Pulling a load on a grade could be a very good test of power IF the weight of both trucks and trailers COMBINED were the same and the gearing (transmission and rear end gearing)in both trucks is the same. That would be hard to do with the gearing unless both were the same make and trans. The dyno is the only level playing field listed in the choices.

 

[MUDDY]

the dyno still wouldnt take into consideration the axle ratio and tire size



mm

 

[Gary - K7GLD]

Yes, I *purposely* included the word "practical" in my question - because I also agree that too many variables are contained in the other choices. The real-world test of pulling a fixed load up a measured incline, measuring time and speed reached at the top seem to *me* to remove most of the variables in a real-life application that involves PRACTICAL application of a given truck's capabilities. And I am talking about the truck as a WHOLE PACKAGE, not just the engine itself.



It's NOT intended as a measure of the gearing, traction, or reaction time of the driver - shucks, it's not even a measure of a precise hp/torque curve, but it IS a good measure of what a given truck will put to the road under conditions many/most trucks are called upon to do daily!



A quarter mile racer might do extremely well in the drags - but POORLY pulling a load up a grade - same with a rig that develops high output at an impractical/unusable RPM on a dyno. My '98 Camaro SS will easily beat my '91 Dodge at the drags - but pulling a load up a grade? FORGET IT!~



Quarter mile runs, Dyno runs and sled pulls all have their place and followers - but for PRACTICAL considerations, *I* feel it's hard to beat a good uphill run with a substantial load attached!

 

[CUMINNTSTRKN]

if you want useable there is no better method than a hill climb. on a dyno egt's aren't an issue becuase it's such a short time period. same as a drag strip and a sled pull. but you start up a 10 mile hill and see who makes it to the top first, that's a test.



jim

 

[Stranger]

Look at it from this side.

Just recently I learned a lot about dynos, drags and sled pulls. One dyno run is equal to about five passes on the drag strip. Reason being; on the strip the load decreases as the pass progresses, where on the dyno the load stays constant, thereby aritificially increasing load!

Therefore, IMVHO, the only true test of power is the actual road! (WOW, what a concept, real world non-destructive (hopefully) testing. ) IOW, "Lift that barge, tote that big A$$ trailer" and so on.

 

[DavidTD]

I think Dyno's are good for testing power differences after mods. Meaning you take a baseline, add a mod, then retest on the same dyno. Bad part of dyno's are that they can give very misleading numbers depending on type and operator input.



Dragstips offer a good source for true hp using the formula's. I contend though that MPH is better for manual equipped trucks.



A hill pull seems best to me as far as how well the truck works. This includes useable power that doesn't exceed EGT limits. I think a run at a 7% hill with 10k pounds is a good start. Plain and simple the trucks should reach the incline with cruise on and see who can pull the best with the least amount of driver input (changing gears, etc). Trucks should be as supplied from factory, and comparable in set-up. whether stock or modified.



I'll give an example I'd like to see.



24v HO/6spd 3500 QC 4:10 gears, loaded SLT+ vs 3500 Duramax/ZF 3500 QC, LT loaded. The GM has 215 tires I believe and the Dodge would have 235's. Over all gearing would be real close between the two. The GM might have a weight advantage, but if so, then so be it. My thinking is if I were the GM truck, I surely wouldn't be hauling around extra weight to "make it even".



So far all I see are comparisons with the Allison transmission. It has five gears to the competion's 4. IT should pull better than the other two if for nothing else for the gearing advantage. I want to see how the manual does to better define the engine perfromance on an even transmission scale.



Just my thoughts... ...

 

[John Berger]

I have learned everything I know about dyno's from this website and I can understand their purpose, but they just give you a working number of what the truck is putting out. When I pulled that 9% grade in North Carolina last week, that to me was the best measure of how the mods on my truck would perform and I was quite pleased. Real world conditions are the best indicator of what our trucks are capable of. The dyno's are a good way to measure the output of your mods. JMO.

 

[DHatfield]

I perfer the best test of power by towing a big trailer up a steep mountain.

 

[Big_Bad_Dually]

Gassers only understand the words DRAG RACE!

The only way I can get the word across is to drag race them, because the only people I have to compete with around here are gassers. No powerjoke or duramax competitors! The gassers already know that i could out pull, tow and dyno them. They just think im a slow heavy duty pickup that couldn't beat a "CHEVY VORTEC 454" (my most recent victum: a 1/2 ton chevy with fresh vortec 454 and 4L80e transmission and a shift kit) until is all they see is a green light and lots of thick black smoke swirling in front of them. OOOO I love the feeling of beating someone who really don't expect it!!!!!!

Brian

P. S. Send some 8 cyl. diesels my way i think i have conquered all the gassers

 

[klenger]

If the reason you bought your truck is to drag race it, then the best test of power is to run it at the drag strip.



If the reason you bought your truck is to run it on the dyno's, then the best test of power is to run it on the dyno.



I bought mine to tow a 10,000 lb 5er. My best test of power is I70 eastbound at Eisenhouer Tunnel.

 

[JAK]

The dyno could be a much more useful test of useful power than it is IF you generate the full torque curve and understand how to interpret it. The 2 numbers that are often quoted (peak hp and peak tq) really don't mean that much on their own. When I bought my Ram the Powerstroke numbers were rated at 235 hp 500 tq. Same hp more tq than my CTD 5 spd. The ps has the advantage in unloaded stoplight wars (except for the ones I've driven - they seemed like slugs to me), the CTD has the advantage in pulling that 10k trailer up a 7% grade. It's all in the torque curve over the entire rpm range. Not many people can thoroughly interpret the full torque curve and predict how the truck will perform under various loads. It's alot of work. It's much more practical to just hook onto that trailer and haul it up a hill. Or see how it does in the 1/4 mile. I guess the best test of useable power is to test it the same way you're going to use it.