Proof that SAE correction for turbo diesels is more wrong then right??????

Gregory, you bring that heap up here and my uncorrected 450hp will whoop your uncorrected 551. Can your fragile psyche take another loss to a Dodge lol?
 
duke1n said:
Gregory, you bring that heap up here and my uncorrected 450hp will whoop your uncorrected 551. Can your fragile psyche take another loss to a Dodge lol?
Click to expand...

:hehe: :hehe: LOL LOL :badidea: :evil :pop:
 
duke1n said:
Not exactly. While it's not linear, it's also not a square either. I'll stipulate that it's been several since I cracked a physics textbook if you'll do the same lmao.

perf1.gif
Click to expand...

When I was in school, we used slide rules. :bang

They told me Pi R Squared, and I knew they were full of it, PIES ARE ROUND!!!

:doh:
 
I'll leave the pissing matches to others...but I will tell y'all what happens to me. I drive my truck all over the country...to the tune of 135,000 miles in about 3 years.
When I'm out in the Rockies...Denver just to pick a spot...I can't light the turbo to save my life and the truck is slower thedn hell....down at sea level...everything works like it should and she hauls the mail.
 
c-hawk said:
:pop:

I tried to word my original post carefully.

I have no doubt that heat, humidity, altitude, etc. have an impact on the power these turbo diesels make.

All i'm saying (atleast what i think i'm saying), is as far as dyno numbers go, uncorrected numbers are probably closer to reality then SAE corrected numbers. The SAE correction adds, or takes away too much on these trucks.
Click to expand...

Yes, SAE is too lenient, but uncorrected does not reflect what we all see when running at altitude, be it towing or racing.

The truth is in the middle.

For marketing purposes, the favorite is STD correction on a hot day.
 
McRat said:
Yes, SAE is too lenient, but uncorrected does not reflect what we all see when running at altitude, be it towing or racing.
Click to expand...

Huh??????:what:

Uncorrected is exactly that...........UNCORRECTED!!:poke:

It is what is TRUELY being put to the ground at a particular location!!

How can you say............"I put down x hp uncorrected but I'm really putting down y hp because it needs to be corrected" Makes absolutly no sense?:what:
 
Last edited:
Greg, think of it like when you are playing some $10 nassau's against some 1s and 2s and you ask them for a couple strokes a side ;)
 
duke1n said:
Greg, think of it like when you are playing some $10 nassau's against some 1s and 2s and you ask them for a couple strokes a side ;)
Click to expand...

Mike,

I understand the intent of the CF in trying to level the playing field for comparing two different locations ;)

But McRat's statement basically says that the uncorrected number is not what is ACTUALLY being put down? Not true:rules:
 
Dockboy said:
Huh??????:what:

Uncorrected is exactly that...........UNCORRECTED!!:poke:

It is what is TRUELY being put to the ground at a particular location!!

How can you say............"I put down x hp uncorrected but I'm really putting down y hp because it needs to be corrected" Makes absolutly no sense?:what:
Click to expand...

Yup.

I look at both the uncorrected numbers and the corrected numbers when tuning. Because I don't get to chose the weather, and I can't always change engine parts on the dyno.

Let's say you put down 675hp uncorrected on a 90 day in the afternoon, then go back, change charger systems, and come back in the morning at 60 deg with the new charger and squeeze out 685 uncorrected.

Which charger do you run?

Look at the corrected SAE numbers, and see perhaps 700 on charger one, and 690 on charger two.

If I'm going to run in thin air, I go with charger one. If not? Charger two.

You can make HP 100hp at time, or you can make 10 changes that are 10 hp each. Both get the same thing done.

An example would be our 2000 Camaro. It was "stock", but had minor tweaks, a few HP at a time. When we were done it ran pretty quick, and nobody understood why. It had no real modifications, just alot of dyno pulls and tweaks. It went from 13.85 to 12.52 without noticeable changes. But since the changes were small, you need to allow for weather when testing.

And yes, I've had a few beers! :blahblah1:
 
duke1n said:
Greg, think of it like when you are playing some $10 nassau's against some 1s and 2s and you ask them for a couple strokes a side ;)
Click to expand...

Mike,

Think of it this way.............

It's like shooting 80 with a 10 but then telling everyone "I shot 2 under today"!!:hehe: :bang LOL
 
Altitude does cause power loss in all engines, proven fact, anybody who has gone for a pilots license can tell you that. Turbo'ed engines suffer a LOT less than NA, but they still loose power.
 
SAE Corrections were written for a none boosted motor running at WOT only. They work very well for what they are for but since any boosted application is not what it's for, you can only use it for comparison on the same day on the same dyno provided conditions do not change during the testing. All chassis dyno's add more errors to the correction terms as well. They assume the air temperature in the dyno room is what is in the intake manifold, SAE calls out for the air to be measured in the intake itself. They also assume the room barometer to be what is in the intake manifold which is not event close in a boosted application let alone most vehicles with air intake systems attached, again SAE calls out for it to be measured in the intake.
 
I might as well comment on this, since I have done a crapload of research on this subject. What is funny, is with all the talk about "SAE Correction factors," there is actually an article written way back in the 1970's titled "Investigation into the correction factors for a turbodiesel engine" (or something like that) by...you guessed it--the SAE. They did a study using a dyno and real world observations and found out that correction factors were much less for turbo diesels than even theory suggested. Why? Back then the only diesels around were big rigs, and the manufacturers weren't stupid. They knew the truck had to perform well at any elevation for hauling so they had 'chargers on them that could light up well at any elevation up to about 7000ft or so, even if they had to maintain a 4:1 pressure ratio instead of 3:1 to keep the boost steady. There is no doubt in my mind elevation affects power, but normally it is less in diesels, using half the percentage of normal correction will get the numbers close all else being equal. If you really want an extreme example of boosted correction, in my research I found an article on a plane that was recently declassified by the millitary that used a three stage turbo system on a GAS motor to compensate for elevation. At sea level the plane was at zero psi, but as elevation went up, the chargers kicked in...they reported at 80,000ft at 90psi of boost the plane still only made 20% of its sea level power. While most diesel trucks won't be driving in the upper atmosphere any time soon, it was just too cool of an add-on to this debate to leave out. Just my .02. Wait, I wrote a lot, maybe .03.

Jason Sands
Associate Editor
Diesel Power Magazine
www.dieselpowermag.com
 
Good stuff Jason. The only thing I would add is that I want to see someone who has a good baseline established at ~sea level to bring their truck up here and we'll see how that baseline compares to what we have at 5500'. Surely someone out there will come to Truckfest who knows exactly what they are making at sea level. Theory schmeory come on up boys & girls.
 
duke1n said:
Good stuff Jason. The only thing I would add is that I want to see someone who has a good baseline established at ~sea level to bring their truck up here and we'll see how that baseline compares to what we have at 5500'. Surely someone out there will come to Truckfest who knows exactly what they are making at sea level. Theory schmeory come on up boys & girls.
Click to expand...


Or vice versa. I'd also be interested in the flipside if anyone has gained a good amount of power coming down from the hills as well.
 
You must log in or register to reply here.
Back
Top