PourinDiesel

Dynojet you should have ran it in 6th gear, that might be where your power went.

Don M

Yep, you need some 6th gear action to make the best numbers

Smkn600CTD

But then you would be getting "numbers" that are "helped" by the gearing.

To get an actual "engine" number, my understanding was that it should be 1:1 gearing, which would be 5th.

Am I missing something here?

Agades

i just dynoed last month with my settup and 5/5/4 and 6/6/4 gave me the best numbers ( 486is HP and 970 ish torque)
anything over that , the wastegate opened right away, exhaust temp shot up and I lost power
we were thinking , not enough air to support the fuel we were dumping in
I went down to 436 horse on 7/7/4, dint bother to go higher

I would put money on it that if you are running the ps62 and wastegate is set at 40 psi that you are just throwing too much fuel at it

either try lower settings or twin turbos (more, cooler air)

this is my theory, be it right or wrong

oh ya we dynoed in 6th on a dynojet

another thing, I see you have the twins program, I ran with the tame version, so I for sure think you are throwing too much fuel for your air supply

I really think over 500 hp is gonna be a stretch for that turbo
may be possible but challenging

abc4yew

Smkn, The gearing doesn't provide any advantage....6th raises the load on the engine and keeps the engine at its best performance rpm. By maxing out rpm early in 5th you had pre mature injector elation. ks

staarma

I don't understand these numbers. Typically uncorrected will be less than corrected except for one circumstance and that's when the actual measured atmospheric numbers outperform SAE's formula. A correction factor is used when the atmospheric numbers are different than the SAE's latest revision of what they say an internal combustion engine will efficiently produce the most HP. What was the correction factor being used by the Dyno? In CA you can see better conditions than the SAE's. For example, the barometric pressure combined with the humidity and air temp can actually outperform the SAE's numbers. A typical correction factor would be 1.05. This means that for every 100 HP you would expect to see 5 more HP using the correction factor. So 400 HP would be corrected to 420 HP. If the atmospheric numbers are better than SAE's you might see a correction factor of .95. If this is the case, then uncorrected 400 HP corrected to a .95 correction factor would equate to 380. This may be the case you saw at the dyno. If your numbers are correct then the correction factor the dyno was using was .908 which is not possible unless the dyno operator wasn't paying attention. Correction factors are used so the variables in conditions can be factored out of the equation when measuring HP and TQ.

Most dyno operators will use uncorrected numbers on forced aspirated vehicles. There is a correction factor for forced aspiration but SAE doesn't publish it or use it. The only condition that gets scued when using a correction factor on forced aspiration is the barometric pressure. This is scued because the turbo is making boost which changes the air pressure, obviously. The humidity and air temp play roles in the combustion as well but not as much as pressure. Pressure does change though in relation to altitude and turbo efficiencies but again, it's not really used in the dyno world.

6th gear is used on inertia dynos because of boost alone. 6th gear loads the engine more so the boost raises higher and maintains throughout the run. There is no "magic" in using 6th gear. If the dyno operators would learn to load the truck with the brake first to build boost and then sample the run, you would see different numbers. The 1:1 gear ratio, 5th in our trucks, will produce the most power from a drivetrain. It's the mechanical efficiency of the 1:1 that allows that along with the moment of inertia and acceleration rate.

Smkn600CTD

That would explain the 520/990 D-max......that was in OD

abc4yew: That's one way to put it

Agades: Boost is 50peak, settles in at 45psi. Its wings over to 50psi about as fast as it can, and drops back to zero just as fast when you let of the pedal. ALMOST thinking the 66/14 is what I should have got.

As for the weather, it was about 50 degrees and raining, altitude I would guessmate 500ft??? As for the corrrection factor, that is why I asked for the "uncorrected" number, to see what it was straight up.

Rick D

They've got pills for that now

cquestad

Your missing the fuel somehow...

Most time you are looking around 10hp per 1 psi at 1400-1500 egt.

55 psi to 550 hp.

Smkn600CTD

The dyno numbers were the same EZ on the truck or unplugged. Going from 1-2 dropped 3hp

Fuel Pressure was 17psi the entire time. And it had smoke on the dyno runs.

I think part of it too is the dyno run was done in 5th, not 6th.

All i know is that it pulls like a rapped ape on crack And will blow some smoke

cquestad

Monitor your rail pressure...sounds like you may have issues. Not all CP3's seem to be created equal.

JCLeary

That was my thought. I drained the rail (BDDL Tow, Ramifier 40%, TST 7x7)on my 2nd pull and got 422hp.

BDDL on Tow and TST standard program on 7x7 gave 526hp.

I think there's a delicate balance between timing/duration/pressure that needs to be found for max power.

Correction factor was .95 on Saturday. If I'm calculating correctly, my uncorrected number would be 553.

staarma

That is correct. Pardon the pun. If the correction factor was .95 then looking at corrected HP actually hinders your numbers. It's kind of silly but that's what SAE gives the dyno world to deal with. A good operator knows the difference though.

Smkn600CTD

Here are the links to the dyno graphs.

This was the best run at 9/9/3

Uncorrected graph.
http://www.dynotuning.com/nor-cal-ch..._rpmactual.jpg

SAE Corrected
http://www.dynotuning.com/nor-cal-ch...004_rpmsae.jpg

I also uploaded the one pic showing the smoke. Its in the "My Gallery" section on here.

JCLeary

My girlfriend recorded my runs. Go figure, the smokiest run was the worst. The cleanest was the highest.

I still think you drained the rail early. I can't wait to get a rail pressure gauge to see what's going on with my truck.

I may buy two, one to mount, and one to bring to dyno day for others to use. I just need to make a pigtail for the rail pressure sensor.