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TDG Mafia Member#67
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Discussion Starter #1
ok i have an appt to get my truck dynoed at the local performance shop this sat. and it will be my first time on the dyno. the guy claims he has run diesels before, but i have my doubts......i know that the dyno has done diesels for sure,...just not sure about the guy runnin it. any pointers or suggestions? also if any 6.0 guys read this, will i get accurate dyno readings if i switch between tunes while on the dyno? or do i need to just run one tune at a time, etc...? Thanks!
Darin
 

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TDG Mafia Member#67
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Discussion Starter #3
ya, its an auto.......so the tunes i have all have tc lockup.....the street has it in 4 & 5 and the xrace has it in 2-5......that not enough? does it not accurately measure the power without that done? or just jump all over the place? i gotta pay $100 to do 3 runs...so i guess i need to get it right! haha
 

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6L strokin said:
ya, its an auto.......so the tunes i have all have tc lockup.....the street has it in 4 & 5 and the xrace has it in 2-5......that not enough? does it not accurately measure the power without that done? or just jump all over the place? i gotta pay $100 to do 3 runs...so i guess i need to get it right! haha

What would be ideal would be for it to stay in 5th gear, in lock-up, from like 1800 or so rpms to where you let off WITHOUT it unlocking, or downshifting into 4th. The higher the gear -the more load it puts on the engine, therefore producing the most power. Dunbar explained this to me while he was dynoing my truck.

For example: my truck(even though it is a dodge, same principle) will stay in O/D and not down shift at full throttle @ 58 mph so 55 is when he starts to accelerate, while holding the brake to spool the turbo, once the turbo is somewhat spooling he goes to full-throttle, but not below 58 mph. So, you might want to do some road testing to see where and when yours WILL NOT downshift and keep it in 5th, throughout the dyno pull:Thumbup: :Thumbup:

I hope this is clearer than it sounds:shrug:

Mikey
 

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TDG Mafia Member#67
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Discussion Starter #6
it actually does make sense! however one ?...how come your not supposed to or its not good or whatever to downshift on the rollers?
but i know the truck pretty good from driving so much........if i have no boost built up and lay into while in 5th gear it will downshift......but if im goin like 55-60 and spool up easy then start gettin in it, it will pull hard all the way up past 100......but it doesnt really start pulling real hard till around 75 when i do that.......unless im sprayin, then it pulls hard soon as the turbos spooled!

any 6.0 guys...the changin tunes while on the dyno ? is still up??
 

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TDG Mafia Member#67
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Discussion Starter #7
blackcloudCTD95 said:
Darin, Good luck!!!!! Get some videos..!! Hopefully You;ll make arround 375-425 Hp..!! :Thumbup:

i dont know anybody else runnin pane or anybody just runnin nos that has put up dyno #s....but im really hoping for somethin like 450 (with pane) ...:smoke :Thumbup: if im under 400..:pointlaugh
 

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Diesel Mafia #67
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Like Everyone said you better know that truck like you know the back of your hand..! Like me I can choose when to lock my TC and or when to unlock it with out a lock up switch.. I can control How much it slips by.. hitting OD at 3psi of boost then slowly rolling on it back up to 5-6 (cruising)

You know your truck pretty good..! You'll do fine! :Thumbup:

SO mikey in a manual I take it you want to lug the motor down a bit so 3-4th gear is what you dyno it at?
 

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6L strokin said:
however one ?...how come your not supposed to or its not good or whatever to downshift on the rollers?

It's not really BAD to downshift, if you can get it to stay in one gear(highest one possible) it provides for a smoother hp & tq curve, more accurate reading. Otherwise, with a downshift, your graph will show a gradual increase, and then spike when it downshifts.

Just kind-of hard to explain to your buddies "see the torque curve, and then here is where it downshifted, it coulda made more power...." ---that sort of thing......
 

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TDG Mafia Member#67
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Discussion Starter #10
ok, i gotcha...so ill try to keep it in 5th then! thanks for the info!
 

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Got Torque?
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I thought I heard somewhere that FOURTH gear is where you want to be because it is straight through. All of the others have extra mechanical dingleberries along for the ride, so you don't get as good of a reading of the power. Anyone else hear that?

In actuality, I think the whole dyno thing is over-rated because most people never ever really run at anywhere near the peak they report. That is, I had mine done when we were tuning it (before the twins work currently on-going), and we put down 486 HP, 996 torque. Sounds great, but that is just one specific condition (one engine speed in one gear). In actuality, for it to run real strong, you need to be near that peak condition, which is basically WOT. Who wants to do that every time they leave a light?

What really counts is how it runs on the street or track the way you like to drive it, and the more I read, the more convinced I am that the peak dyno number ANY truck reports has little do do with it. Someone used the term "dyno queen" in some thread a while back, and that pretty much sums it up. So, along the lines of my thought, if you have a street truck and just want it to be pretty fast off the line and good at merging WITHOUT beating the piss out of it, how do we measure that on the dyno? I say you look at area under the curve. Let me say it again: area under the curve. I work in an unrelated industry where we use that a lot and it is so much more useful than peak levels. In fact, peak levels are associated with damage! I'm in the pharmaceuticals world, and peak blood levels relate to toxicity, whereas area under the curve relate to efficacy of the drug.

Applying that to our trucks, if you looked at a dyno curve as one briskly accelerates through the gears up to, say, 75mph, you can get a good idea of how efficiently that power is being delivered. Area under the curve is the area under the HP vs. time or RPM curve. If you look at the number you get on the area under the curve for HP vs. RPM (a standard dyno plot), you could program the file to run through the gears shifting at, say, 3000RPM. That would correspond to medium acceleration, nothing that beats the piss out of the truck. For me, that's where I want it to run strong. I'll save the WOT for when I really really need it, but I don't want to have to go WOT all the time. So, getting back to the plot, if you were able to see the area under such a curve and your tuning was such that you could deliver nice power below 3000 RPM, you'd have a real nice street ride that gave solid acceleration without having to run at the edge of destruction all the time. This means getting the power delivery up earlier and holding it there longer. Be great to have 400RWHP throughout the band at medium throttle, but have the 500+ at WOT if you really needed it. I got this idea from driving my SRT. It is like that. Medium throttle still crushes almost anything that tries me. And the engine barely works up a sweat. I think the feel on the road is immensely more important than the peak dyno number.

Or you could just do it at the track. Basically, I don't give much credence to peak HP numbers on a dyno. Good for the trophy case, and maybe important if you are running a race truck, but 99% of the guys here are running street trucks that they want to have an edge over the other vehicles on the road with, that want to have that seat of the pants thrust with minimal engine effort, etc. In my mind, the tuning to do that is in another universe than the tuning that yields peak HP on a dyno.

Ralph
 

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TDG Mafia Member#67
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Discussion Starter #12
i RARELY read extremely long posts...but coming from you i figured it would be good. which it is! and i agree with you, that is kinda why i wondered why its not good to go through gears, etc. when dynoing. i have no idea what the ideal gear is to dyno either......ive always heard 4th gear is best too, but i know without gettin a special tune, 5th would be a lot easier to hold! eric was outta town so i couldnt get ahold of him to ask about the tuning, etc.
1 reason im wanting to dyno, see what its puttin out, braggin rights like you said
2nd reason, im spraying propane and want to see how much extra power im adding with that to see if im added too much power (spraying too much pane) or if i have room to spray a lil more.
3rd reason, i figured i may be able to send the dyno sheets to my tuner (innovative) and he may be able to tweak here and there to make the tunes even better.

Thanks for all the help guys, im on my way now so i hope all goes well and i put down some big #s! LOL
 

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TDG Mafia Member#67
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Discussion Starter #15
blackcloudCTD95 said:
congrats darin....!!! :Thumbup:
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:pointlaugh your sucha homo! how you gonna post my #s before i get to? :popcorn:

at least get em right!.....490 horse, 860 torque:Thumbup: bout to make a new post with the dyno sheets and vids!:poke:
 

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Diesel Mafia #67
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6L strokin said:
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:pointlaugh your sucha homo! how you gonna post my #s before i get to? :popcorn:

at least get em right!.....490 horse, 860 torque:Thumbup: bout to make a new post with the dyno sheets and vids!:poke:

LOL LOL LOL .. I dont knw.. may-b I was on the phone with you when you were telling me those numbers..!
 
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