Dynoing the truck

[MikeGenova]

Going to be putting my truck on a dyno sometime soon and was wondering what are some secrets to putting up good numbers. I have never driven on a dyno before and im not sure of the proper way of doing a pull. What RPMs do you start the pull at?

 

[AH64ID]

I get the truck in 6th at about 1500 rpms then roll into the throttle, it spools quick and gives you good numbers in the 1800+ rpm range. I once did a run starting at 1000 in 6th and there was definatly more power in the 1500-1800 range from a lower turbo spool.

If I ever do a new baseline I will probably try about 1200 in 6th and use the brake to build a little boost before going WOT.

The biggest thing is to do it the same way on all your runs.

 

[MikeGenova]

Do you recommend turning the rail pressure up with the smarty for the pulls?

 

[AH64ID]

Depends on if your going for numbers, or for what you get on your normal settings.

I like to dyno what I run every day and towing just to see what I make.

 

[MikeGenova]

Yeah I would like to get everyday numbers, and also see the highest number my truck will put down.

 

[Motorhead]

I get the truck in 6th at about 1500 rpms then roll into the throttle, it spools quick and gives you good numbers in the 1800+ rpm range. I once did a run starting at 1000 in 6th and there was definatly more power in the 1500-1800 range from a lower turbo spool.



If I ever do a new baseline I will probably try about 1200 in 6th and use the brake to build a little boost before going WOT.



The biggest thing is to do it the same way on all your runs.

I thought that you want to be in a direct gear for a dyno run. (5th for a 6 spd stick or 3rd lock for auto)

 

[ENafziger]

I personally don't feel comfortable getting into the throttle heavy at less than 1500 - 1600 rpm. In fact, I usually wait until 1800 before full throttle.

If you are at 1000 ft-lbs or more torque, the G56 is definately on borrowed time at low rpms.

--Eric

 

[MChrist]

I would like to put my truck on the dyno, also. Mostly to see how it compares to my iPhone app called "dynolicious". I've only run a few times and on low Smarty settings, and it will generally be in the 400-440 range (rwhp). Haven't tried on SW9, yet!!!

 

[cerberusiam]

I thought that you want to be in a direct gear for a dyno run. (5th for a 6 spd stick or 3rd lock for auto)

That will take about 20% off the max numbers in a direct gear. A DynoJet will not fully load these engines and the direct gear leverage just lowers the amount of load the engine hits during the run.



There are tricks to getting the engine to load up close to full load on a dyno like riding the brakes, making sure boost is up out of the defuel range, etc. Even those are only moderately effective as most dynos of this type never exceed 80-85% engine load using every trick to fool it. Without doing that a lot of times 70% is the max load you can get to.

If you are at 1000 ft-lbs or more torque, the G56 is definately on borrowed time at low rpms.

The TQ is calculated number on a dyno and there is only the load the dyno puts on it. Its far cry from what happens when you put a trailer on it and hit the go-pedal. You literally dyno all day long with no issues and break driveline pieces in daily driving conditions with less throttle.

 

[Shadrach]

Two of my buddies who have run HD truck dynos for years always run in direct. That the standard way of doing it. Like an accountant you can make anything look good if you play "with the numbers" Shadrach

 

[AH64ID]

Everything I have ever hears is to run in 6th to load the motor. 5th would be too short of a run and not enough load to get good numbers.

 

[cerberusiam]

Two of my buddies who have run HD truck dynos for years always run in direct. That the standard way of doing it. Like an accountant you can make anything look good if you play "with the numbers" Shadrach

Sorry but your being led astray, direct is not a "standard" for an accelerometer type dyno used as a tuning tool. It is inadequate to tune the rpm range with, and, misleading when it comes to actual performance. After all, direct is not the gear used to do the work. Whatever you see there has no application in a real use scenarios.



You cannot "play" with real numbers on a dyno, it is what it is when the engine is as close to full load as possible and the runs are as identical as possible. The only "playing" going on is the dynoing in direct drive, not operating the dyno the same way every run, refusing to make the run to optimize the engine setup, using correction factors incorrectly, etc. I'll agree with you there, the "playing" is not going to give an accurate picture. :-laf



A dyno is a tuning tool, one run for bragging rights is just a number with no reference. It takes multiple runs to establish a baseline and even more to test changes to see if they are going in the right direction. One needs to run on the SAME dyno with the SAME operator(s) and make the run the SAME way every time, or, you have disjointed data that may not correlate and tells you nothing about direction. All that work and those dyno numbers need to be validated in real life to mean anything.

 

[RustyJC]

When I had my 2002, the dyno operator and I tried it both ways. 3 pulls in 5th (NV5600) on a Dynojet 246C averaged ~325 rear wheel HP. 3 pulls in 6th averaged 347/762.



Rusty

 

[Shadrach]

One of the reasons the HD truck dealers around here use "Direct" is that you eliminate the variables with different O/D ratios. Of course they are dynoing to make sure the engine is operating properly, checking for problems or for breaking in a new engine. With a few exceptions, by some truck owners, it is not used for "bragging rights ". Shadrach