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Diesel Nutbag
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Discussion Starter #1
Most of you know my opinion of SAE Correction Factors when it comes to Turbo diesels. Especially when it comes to running nitrous.

Well, I had the oppurtunity to put my theory to the test in the past couple weeks. Two weeks ago I dynoed on David Dunbars Dynojet 248C in Tenn. The CF that day was 1.04. Dynoed 574 #2 only and 758 w/nitrous corrected. Uncorrected actual power put to the dyno was 551 #2 only and 727 w/nitrous.

This weekend I dynoed on Kauffmans Dynojet 248C. The CF was 1.00, or in other words, nothing. Take a guess what I put down in the same settings?? 552 #2 only and 729 w/nitrous!!!!

So you tell me..........did I mysteriously loose 22 hp on #2 and 30 hp on nitrous as the corrected numbers would indicate?? Or is it that the CF designed for naturally asspirated gas motors is not valid for forced induction diesels given the fact I put the nearly exact same hp to the ground at both locations despite the difference in alltitude and correction factor????

Lets hear what you think!!
 
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Looks to me like your onto something here Greg!

BTW - AWESOME power! :Thumbup:
 

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I think alt definatly effects the way our trucks run. I dynoed 545hp corrected on maddogs dyno (portable dynojet same as dunbars) in denver, then 2 weeks later dynoed in KC area im missouri on floor it diesels (dyno dynamics load cell) and did 551 uncorrected, then about a month or so back did 558 uncorrected in OKC on a mustang dyno. At denver i was running 13.6's and down here i run 13.1's, was ~2 mph slower in denver.

Bandimere is 5800' feet or so and i think im around 1000-1200' elevation.

Here's what the calcs have to say:

denver 7000 lbs (no tool box and low fuel)- i ran a low 101 and a high 101 mph pass so i'll use 101.5 mph = 496 hp

kansas 7300 lbs and average 103.5 mph trap = 549 hp.

just my .02
 

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i agree with lukecline
 
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I agree that elevation plays a factor. How much I don't know, I am sure someone with a science background can help out here. Although to me it makes sense that more dense air "lower elevation" would net higher actual numbers than thinner air "higher elevation". So therefore you would need some sort of correction factor to try and bring the numbers back into check.
If the motor is N/A or turbo/super charged I do not think makes a difference. It still boils down to the amount of oxygen availble in X volume of air.

Why your numbers were near the same uncorrected both places I am not sure. I also think ambient air temperature, humidity, exact cetane value of the fuel, the dyno, and the dyno operator would all play into the scenario.

No matter what, congrats again on the numbers.
 

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Diesel Nutbag
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Discussion Starter #6
Luke,

I think you need to find another brand of dyno to try!!!LOL

Comparing numbers from different types of dynos at different altitudes is like comparing apples and oranges:poke:

Riddle me this grasshopper:sly:

A truck setup nearly Identical to yours dynoed 484 on Dunbars 248C with a 1.04 CF

Uncorrected that is 465

You dynoed 545 on Maddogs 248C with a CF of what, 1.17?

Uncorrected that is 465

:shrug:

I can gaurantee you your truck will make 465-480 on a 248C at sea level with a 1.00 CF:poke: :popcorn:

In fact, I saw a similar one do only 422 this weekend:sly:
 

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kansas 7300 lbs and average 103.5 mph trap = 549 hp
Then explain that docksquirell
 

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Dockboy said:
Luke,

I think you need to find another brand of dyno to try!!!LOL

Comparing numbers from different types of dynos at different altitudes is like comparing apples and oranges:poke:

Riddle me this grasshopper:sly:

A truck setup nearly Identical to yours dynoed 484 on Dunbars 248C with a 1.04 CF

Uncorrected that is 465

You dynoed 545 on Maddogs 248C with a CF of what, 1.17?

Uncorrected that is 465

:shrug:

I can gaurantee you your truck will make 465-480 on a 248C at sea level with a 1.00 CF:poke: :popcorn:

In fact, I saw a similar one do only 422 this weekend:sly:
Comparing 3 different trucks is like comparing 3 different dynos:poke:

I dont know what the cf was on maddogs dyno and i really dont care. You are a big fan the of trap speed/ hp calcs and they have always matched my dyno #'s. Theres too many different variables to even think about comparing my truck to james' and who ever else your talking about.:shrug:. Show me another 7300lb truck that is trapping at 103+ with 465 hp and i'll shut up....wait there isnt. Thats why all the DI trucks with MM's and bb turbos that dyno 450 are all mid/ high 13 sec trucks.
 

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hahaha, poor dockboy
sorry just like harassing you
robert
 

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I agree with Dockboy on this subject. CF's were designed for N/A motors. But, me myself have never changed altitudes, dynos, or CF's to see a difference. But I do know people that have and seems to be little difference. Good numbers again Greg!!
 

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Dockboy said:
Luke,

It is very simple to prove me wrong!! ;)

Dyno on another 248C where there is a lower CF:poke: :Thumbup:
I think ive backed my #'s up enough.

You want to prove me wrong, you foot the bill for dyno and fuel and i'll go dyno.:poke:

Just because im running hybrids and 1 superduty hpop doesnt mean i cant make good power too:stirthepot: .
 

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lukecline said:
I think ive backed my #'s up enough.

You want to prove me wrong, you foot the bill for dyno and fuel and i'll go dyno.:poke:

Just because im running hybrids and 1 superduty hpop doesnt mean i cant make good power too:stirthepot: .

agreed!
 

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Dockboy in Colorado:
729hp x 1.20 CF = 875 hp:popcorn:

:splat
Blowby get's stomped
 

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But what uncorrected HP would Dockboy make up here?

Tom
 

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Diesel Nutbag
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Discussion Starter #16
Blowby said:
Dockboy in Colorado:
729hp x 1.20 CF = 875 hp:popcorn:

:splat
Blowby get's stomped
LOL:Thumbup:

I think you guys are missing the point of this thread:shrug:

It is not about discrediting anyone's numbers, but about trying to determine how and if the SAE CF works with our engines!!

comparing numbers from different type dynos at different altitudes is pointless to the discussion because they can not be compared with any accuracy:shrug:

I shared my findings of the comparison of actual vs. corrected on the same type dyno with 2 different CF's. Does anyone else have any similar type data?:shrug:
 

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ok i will agree that the cf with gas is totaly bogus, but there needs to be cf on #2 only, maybe not as much as most use, but some, i havn't done much testing but i know when i go to ks or ne to pull my truck has MORE POWER, and less smoke, that tells me something
but what do i know i am just a kid HAHA
 

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Dockboy said:
comparing numbers from different type dynos at different altitudes is pointless to the discussion because they can not be compared with any accuracy:shrug:

I shared my findings of the comparison of actual vs. corrected on the same type dyno with 2 different CF's. Does anyone else have any similar type data?:shrug:
Track times dont count? You guys always say that the track shows what hp your really putting down, so i guess none of my times count:shrug:

denver 7k lbs 101.5 trap = 496 hp
kansas 7300 lbs 103.5 trap = 549 hp

So about a %10 difference based on 4600- 4800' ele change.


What is the elevation difference between kaufmans and smokin in the smokies event? If its less than 500' then the hp difference would be %1 or less and being that it was also done on two different dynoes etc.... it would be possible to dyno consistently on two different dynos like you did.

Maybe im missing something, but track numbers dont lie:shrug:
 
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According to this site the elevation of Dillsburg, PA. is 600' My place here in TN. where we held Smokin' is 1900'. Of course this assumes Kaufman's is at the same elevation as the town of Dillsburg.
 

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I think most people would agree that the SAE CF isn't completely accurate, but comparing uncorrected numbers isn't accurate either. Our uncorrected numbers here in CO will be lower than the same truck uncorrected numbers at lower elevations, and the bigger the altitude difference, the bigger the difference in the numbers. Higher elevation causes our trucks to make less power; that's a fact.
 
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