Which is exactly why I did my lengthy post #212 here... https://www.ford-trucks.com/forums/8...ml#post7535663 ...explaining why back-to-back runs on an inertial dyno aren't a very accurate method for "measuring" if a particular mod is responsible for an observed change in dyno HP!

You saw an 11 HP difference with no change but if for example you'd changed air filters between runs and saw the same 11 HP difference everyone would immediately claim that the 11 HP difference was caused by changing the air filter!

Ok for your tranny I guess 5th gear is direct and 6th is OD. His explanation isn't the best but on an inertial dyno you will get a higher HP reading in OD compared to direct gear! In OD you can load the engine more and get the boost up and this helps the engine to produce a little more "actual" HP but due to other considerations you might also get a little higher "fictitious" HP reading in OD due to the inertial characteristics of the dyno itself! This means if you compare your dyno HP with the "typical" baseline case where trucks dyno in direct gear you're comparing apples and oranges!


Well I guess when it comes to dyno runs it's better to have an "exploding head" which can usually be fixed with an aspirin than to have an "exploding engine"! I'll see if I can help some with your exploding head!

The standard reference temperature used in the atmospheric CF equation is 537-460=77 F and I'll use your stated To=65 F in the equation. Your location is just south of Omaha so I'll use 1,040 ft for your altitude which means that if you didn't have a high or low pressure front passing by at the time of the dyno run your "nominal" absolute barometric pressure was 1.04" Hg less than the standard 29.22" Hg value at sea level so I'll use Bdo=28.18" Hg in the equation. So your atmospheric CF is...

CF=(1.18)x{(29.22)/(Bdo)}x{(To+460)/(537)}-(0.18)=(1.18)x{(29.22)/(28.18)}x{(65+460)/(537)}-(0.18)=(1.18)x{(1.037)}x{(0.978)}-(0.18)=(1.197)-(0.18)=1.017

...and this means that your "uncorrected" dyno HP needs to be multiplied by a factor x1.017 so for example your 370 HP becomes a "corrected" 370x1.017=376 HP!

If your run was done on a "standard day" at sea level which means at 77 F and a 29.22" Hg barometric pressure your dyno run should've produced 376 HP! Using "corrected" HP levels the playing field and allows everyone to more realistically compare their dyno results!

I recommend to always get both "uncorrected" and "corrected" print outs. The dyno computer can process the same data file multiple times to give both and you can even ask for print outs using several different smoothing correction factors. These data files are stored and asking for this doesn't disrupt the flow of events because the data can be processed and printed at any time and even mailed to you after the event is over!

 

I would like to know what specific mods you are running. How much gain do you think you are getting from the methanol?

 

Hey ernstugene, did you give the 72 oz steak a shot?

 

We took the "caddy" ride to the "Big Tex" several years ago and several tables away some guy was trying to eat one of those "monster steaks" and before we were through with our regular size steaks he called for the "barf bucket" so we decided that one night out at the "Big Tex" was one too many! So this visit we ate at several nicer steak houses instead!

BTW I thought the "smell of money" was "oil" not the god awful cow orders we had to contend with when the wind shifted in the wrong direction! We were at the new RV park at I-40 exit 60 just west of town!

 

Yea I have lived here for 35 years and am still not use to the smell of money. And the Big Texan is just a tourist trap. I have only been out there two times in 35 years.

 

check sig. prolly 60 - 70hp

 

Thanks, just wanting to compare what I done.

 

And to think... I've heard so many people bash Water/Meth, claiming it isn't a HP drug... The dyno sheet says otherwise and that's enough proof for me. Congrats!

 

idont have a dyno sheet for my first one in 07, but i did 292/648 without meth and a few other minor mods.

 

I'd like to try and calculate how efficiently the meth produces its HP compared to the 37% efficiency for #2 diesel. Maybe you know the lb/min or gal/min flow rate for the meth injection or if it's only known as a % of the CFM airflow give me those details and I'll estimate the mass meth flow using my PSD airflow model.

 

how did you do???