1st Dyno Run - What do you think?

[Billy14]

My daughter's boyfriend finally convinced me to have my big buggy run on a Dynojet here in town.

Somewhat reluctant, I agreed & suprisingly was blown away as well as the owner & numerous others present during the run. Prior to the results, here's the kicker. I turned the A/C on to get the temp up to let the Juice flow. Guess what! I forgot to turn it off during the run.

Hot Juice level 4-normal with A/C ON:
398.1 H.P. at the wheels
706.4 ft. lbs. of torque

Scared the hell out of all of us including the owner when she dropped into 3rd. Broke both 295's loose on the drums & thought the straps were going to let loose. The peak nos. came in 3rd.

What do you think?

Billy

[sdaver]

SOUNDS STRONG TO ME :D :D :D DAVE

[Duramaxerado]

EXCELLENT!!!!! :D

I bet that puppy gets up and hauls AZZZZ!!!!!!! :D


Aside from the performance, how do you like your juice in normal driving conditions? Truck still seem to run good?

Smoke alot??


What exhaust system do you have on your truck?

[Billy14]

Duramaxerado,

Performance wise, the truck is completely stock with exception of the Hot Juice. I run level 4-normal all the time & level 2-tow/haul pulling 16,000 lbs. a couple times a month.

If I run it hard for 3 to 4 consecutive shift cycles I will get an occasional teeth wrenching shift from 2nd - 3rd & others have posted the same. I expect this might be fixed with future updates. Other than this, it runs out better overall than it ever has with 34,000 miles. The people at Edge have been wonderful with fixes to most all glithes we have posted. I feel confident that with some time, this will be addressed as well.

I can't describe how strong this truck runs out! :D :D The bad part is, you get used to it & want more. tongue.gif

On Edit: On my truck, there is little smoke. If you are cruising & ease down past half pedal without downshifting, you'll dump a little. The key (my experience) is to pull up some boost & then drop the pedal. Very little. Hit it hard from a dead stop & idle, expect a pretty good puff. You have to learn how to drive the Juice. It's FUN smile.gif

Billy

[ 02-19-2003: Message edited by: Billy14 ]</p>

[SoMnDMAX]

I hate to burst your bubble, but those numbers are skewed. To get an accurate dyno run, the trans MUST be in fourth gear with the converter locked. This currently can only be done with a Tech II scan tool. The trans cannot upshift, and it cannot downshift.

Realistic HP numbers would be in the 350-360ish range.

Sorry. :(

[Billy14]

SoMnDMAX,

Thanks Buddy. Let me know when I can do something for you too someday! tongue.gif

By the way, which is getting fooled here? Us, or the Dyno?

It seems (logically speaking) that the power applied to the drums by the tires is what it is. How can the tranny or gear effect the bottom line? I'm ignorant here & don't like erroneous information. Makes you look like a Dummy down the road if you know what I mean. :eek: Help me out. I think I remember reading something Kennedy posted about this.

Billy

[orange2]

I think it has to do with the shock of the downshift, I am assuming there was a pretty big spike in the curve, which is the high number you saw. If I am incorrect I am just speculating.

[Billy14]

orange2,

Don't know but the peak was in 3rd before it ever hit O.D. :confused: The curve dropped off rapidy when ot hit O.D.

Does this apply only to the Allison or to all trannies? I would certainly think that the people running the thing would be aware of this if it applied to all. I was told to start rolling & hit it just as they did with the gassers.

Billy

[NWDmax]

I think you have got to be in a 1 to 1 ratio.Not under or over driven.
Not sure but I think thats it.

[ 02-20-2003: Message edited by: NWDmax ]</p>

[ZFMax]

No, that's not true ... the Dynojet inertia dyno can measure hp regardless of the gear the vehicle is in. In lower gears, it sees more torque and less rpm at the wheels, but remember, it's showing engine torque, not rear wheel torque. Which is why it needs the tach pickup before it'll give torque, it needs it in order to understand the total gear reduction between the drum and the crankshaft.

[SoCalDMAX]

Those numbers do sound good, a little too good.

I agree with SoMN, I've been told that the tranny needs to get locked in 4th (1:1 ratio) and the Tech 2 is the best way to do it. All of these trucks dyno at 240-250hp, a few maybe a little more, but the majority at 245rwhp. The Hot Juice provides an extra 120hp which should be 365rwhp, give or take 10.

Mine dyno'd at 247.6hp stock and 331.9hp with Juice level 4 (an 84.3hp gain out of an advertised 90hp.) The operator who did mine had a lot of Duramax runs and knew exactly how to get consistent readings.
__________________________________________________
On edit: The operator did a drivetrain loss test after my first run, the numbers had been skewed due to the wrong numbers in the system even though the previous truck was also a Duramax."
__________________________________________________

Still, worst case scenario, you might have been getting 365rwhp. That might be approx. 430-440hp at the crank. Now how many other vehicles do you run across making that kind of hp and torque numbers? Not to mention out of a diesel.

Regardless of how fast some people might think they are, they're in for a BIG surprise when they try to pass you! :eek:

Regards, Steve

[ 02-20-2003: Message edited by: SoCalDMAX ]</p>

[Billy14]

SoCalDMAX,

Don't know Steve. I'm obviously a little confused of the Dyno nos. Like I mentioned, I would think someone that owns a Dynojet would know what to do. This particular place has such a reputation that he's pulling people in all the way from CA.

What I do know is, after provoked at 2 stop lights this tank tore up a 5.0 car that was cammed, headers, & 4 speed manual by 5 truck lengths 0-60. This was also before I upgraded to the Hot Juice. Go figure!

Thanks for the input,

Billy

[SoMnDMAX]

Billy 14, I didn't mean to be a dink and downplay your numbers. Certainly not my intention. No harm meant, hopefully none taken. smile.gif

In regards to the DynoJet, every time I've been on one with my own vehicles, or around for tuning sessions on friend's vehicles, all ACCURATE pulls had to be made in 1:1 ratio- fourth gear with the Allison, third on a TH400, etc. But, ZFMax may have a point- the calculations could be done to figure it out. Billy, did the dyno shop hook up the optical tach lead?

I will hold to my original estimate- 350-360 HP.

[Billy14]

SoMnDMAX,

The problem with text messages is they can be interpreted in a manner not intended. I haven't taken offense to any of the posts including yours. smile.gif I would just like to know if I spent the money for some numbers that aren't accurate. :(

They did locate the optical sensor. Had to pull the plastic skid plate off the front.

I would think that with today's High Tech equipment & software, a machine would or could be able to accurately calculate H.P. in any gear but, that may not be the case here.

Thanks again,

Billy

ON EDIT: Where is Mackin & Kennedy anyway? I bet those two guys have a few answers here!

[ 02-20-2003: Message edited by: Billy14 ]</p>

[2K2AD]

Billy - How was your seat adjusted? :D

[Kennedy]

Those numbers are a little high, but nevertheless, you should look to do a baseline and then test mods the same way on the same dyno.

On the road posting using my laptop...

[Paintdude]

What John said.. We dyno motorcycles on same dyno stock then after every modification..This tells you what is going on..

My bike dynoes anywere from 133 hp to 137hp(Dynojet 250 both of them) depending on what dyno I am on..Kind of hard to tune on different dynos..The bigger the Hp number the more the difference from dyno to dyno..

A motorcycle is dynoed in 4th gear..Some guys will dyno your bike in all the gears shifting on the fly, when they do this you get spikes in the reading, usually way high, incorrect numbers..You dont count the spikes..

Plus tire pressure can effect the reading and amount of oil or weight of oil in the engine..

this is my experiance with dynoes over the past 3 years..

[SoCalDMAX]

I've been talking to 3 different shops about swapping cams/dyno tuning a Northstar. Promised dyno numbers vary by 125hp. The most open (I think honest) tuner told me to come on in and he could show me how they can change power output by 35rwhp just by changing CV angle, tire pressure and other variables.

The important thing is how much power you've gained, not necessarily absolute numbers. we get spoiled with these great trucks.

I'll tell ya, after driving this truck, I want everything else I drive to pull like a semi at 1600rpm... tuners start talking about shifting the Northstar power band up and setting the rev limiter at 7500. I tell them, no. I want new cams, indexed, I want midrange grunt, I'm not revving over 6000 and I want to accelerate from 1600rpm up a dune.

They scratch their heads and say OK.... ;)

Regards, Steve

[Paintdude]

That is what makes a Harley so much fun,torque..A good running Hd will do 100 hp and 100 ft lbs of torque or more, where my inline 4 cyclinder engine will do 135hp and 74 ft lbs of torque..I am changing engines this spring to get 85 ft lbs of torque and only 128 hp...I want the torque..

Hp is generally the drag strip winner(short stroke and large bore)..But you ride and drive torque on the street..

[txtuner]

The reason hp dropped off in OD is because you hit the speed limiter before you reached redline! smile.gif The infor you have been given is correct, dynos are meant to be ran with a 1:1 ratio. That is a long explanation so we won't go there. Sounds like your truck should run awful good though!

[Kennedy]

Paintdude,

Mine ran 104lb/ft and 104.8HP rear wheel at Tomahawk outside in 60

[Paintdude]

John, You have some money in that baby to be getting those numbers..do you ever go to the Superbike races at Elkart Lake..We go everyear..It is a great time, bring your bike and a see some racing..For 25 bucks they let us ride around the track and follow a pace car(4 mile track 4 laps)I have seen 130mph on a parade lap on my speedo..I cant say enough how much fun Elkart Lake is..One of my freinds is the logistics manager for Skip Barber Racing and we hang out with him at thier facility there during the races.....

Leaving for Daytona Thurday morning.. smile.gif

[Kennedy]

With a 32

[Paintdude]

Everyone rides everything up there..what makes it so nice is you can ride your bike on the road on the ouside of the track and go from local to local and watch the races from anyplace..No walking, just riding....Alot of fun and in Wisconsin no less.. smile.gif

I sold my Harley(Superglide 1200 kick start only, with close ratio trans,etc,etc) about 12 years ago to pay off my house..I figure the Truck and the *** bike is enough of a money pit, for now..I may get another someday , but I just do not know..You can have a Duramax for what a tricked out Hd will end up costing you anymore..

Bourgett had supper with a buddie of mine last weekend at the MC dealershow in Indy..My buddie steve works for Holly-NOS and Bourgett(he sold over 1000 units-bikes last year :eek: ) wants him to put NOS on his Cigarette boat so he can break 200mph on the water..Better him than Me...I seen the Chopper Inc, bike over there also..Some cool stuff..Art is more like it..

[Billy14]

Hmmmmmmmmmmmmm!

Are these bikes Diesels?

ON EDIT: Yeah I know. No one likes a smart a$$ :D :D

Billy

[ 02-24-2003: Message edited by: Billy14 ]</p>

[Paintdude]

A Harley could almost be classified a deisel with the torque numbers they put out..

I am a smart A$$ also, so no problem here..I just dont do much of it around here..I try to be good.. :D

[xwing]

The gear the truck is in doesn't matter MUCH to hp on dyno, as long as you try to do it in at least 3rd gear. 1st gear will read low, 2nd a bit low.
You will get lower hp numbers in lower gears and higher numbers in higher gears, because higher gears allow the motor to build boost and work against a load more; 1st gear the truck is accelerating so fast the boost lags somewhat, the torque at each rpm is less than when the truck has time to build boost/torque in a higher gear, and engine/driveline inertia is more of a factor.

On engine dynos, an "Acceleration Test" where engine hp is determined as engine ACCELERATES will give lower hp than a "Step Test" where the engine is braked to HOLD a certain rpm and hp reading is then given.

You don't need to be in a 1:1 gear ratio. 1:1 tends to be most efficient at power transmission, but in the end it is ALL:
HP = Torque x RPM...
If you are in a lower gear you will make more torque but less (wheel)rpm on a chassis dyno; in a higher gear you see less torque, but more (wheel) rpm so it all balances out.

You don't want to cherrypick a hp/torque that comes on an up or downshift, but want to see a smooth curve upward to peak then downward to get a valid set of numbers.

Dynojet dynos have the reputation of being sorta "optimistic" on rearwheel hp compared to say Mustang and other brands; so Toyota Supra people love citing Dynojet numbers for hp claims. Some have said between 5 and 20% higher than other dynos...I dunno.
A good hp estimate can be mph at end of quartermile dragrace, entered into a formula taking vehicle wt and 1/4 mile mph into account. Since a certain wt propelled by a certain hp will give a certain MPH, these are good real world estimates, though they don't take into account wind resistance (a factor over 70mph more and more), nor our Allison trannies lazy shifting and tranny-slip-detecting-powerdown "feature" which seems to cost real mph/acceleration with Juice type hp levels/boxes.

[ 02-24-2003: Message edited by: xwing ]</p>