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Discussion Starter #1
will let Bob and Greg tell what is going on with their trucks.


I got there about 9:45 and did not get off the dyno until 4:30 PM. I was 6th on their main list but got bumped down by some Fords. Cannot really blame them as it was their event. There were also some Dodges there. Most of the Fords were getting about 275 ish HP and 575 ish lb/ft. I ran with the Juice on 90 hp and got 356 HP and 576 lb/ft. Not sure that the dyno operator was letting it fully locked up in 4th gear. Did not have access to a Tech II so just had to run with the OD locked out and tow haul. Then stacked the Predator at 120 hp. That netted 445 HP and 777.6 lb/ft. Should have run a baseline with just the Juice and no power adds. Bob did run his 03 GMC with on tune 0, so I am sure that I would have had about the same results. Had to pull the outer wheels to get the truck to fit on the dyno. And had to pull the front "skid plate" under the front of the engine to get the optical sensor attached. The Ford boys were shakin at this point. They tracked the results on a spreadsheet for all of the trucks. Hope to get a copy of it. Bob ran a baseline with the Juice 0 tune and then with a 90 HP tune. I will let him crow about that. Greg ran various combinations. I will let him also tell you about that. The Ford folks were very nice and a good time by all. The only thing that was missing was the beer. Thanks for getting this together and glad I was not out of town. Good to meet you boys!






JessEdited by: jesshd
 

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464HP 787 TQ..... VA 110/and a whole lot more and Quad 135 stealth tuner! Thanks to CPMAC!!!! Dude you will always be the man! Thanks for the "loaner" Parts and showing the guy's I work with who the punk's are! I am headed to PFI in Fort Collins monday I am going to see if it will hit 500 I know its got it in it.... Oh well I want to hear Bob's number's where is he at! oh Jess call me sometime before you leave for Brazil we can go out for a few drinks and BS! Thanks again guys for you help and words of encouragement!





GregEdited by: Smokin Deezul
 

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Hey guys-


It was nice to meet some other DMAX's in the area. I think the best quote I heard from one of the Dyno Pro guys was the fact that the DMAX's were showing up the Fords and it was their event!! hehehehe


Well I don't have my dyno sheet with me so the numbers may be off by a little. The sreadsheet stops right before my run, figures... So from memory, with the 4" Summit System and Juice on Level 0, I put out 302hp and 514 tq. With the Juice set to level 4 the last two runs were almost identical, 375.1hp and 684tq. Not too shabby at all. I kept trying to figure out why my "stock" run was so high. Then I learned that level 0 still adds around 18hp with just the timing and no fuel. Oh well, should've disconnected the box for that first run. But from the looks of it my Summit 4" exhaust must have added around 20hp or so, being as that most stock DMAX's dyno around 260hp or so. What a bargain!!



Bob
 

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That was a pretty good jump for adding on the Predator at 120 stacked with Juice. I ran both stacked, regualr juice level 4 and predator in 100hp and only netted 365hp, and 666 ft-lbs. Most accurate runs are done 4th gear, convertor locked. Think your results will be much lower if it was done properly.


Man whats a dyno meet like with no beer
, Everybody must have been in their best behavior.


Bill
 

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we dyno'd in 4th gear tow haul locked in and achieved those numbers i gained a bunch more hp today dyno proven 3 pulls but whats it matter if I am not doing it right i guess 3 runs between 501 and 505 hp and torque between 929 and 935 are bunk numbers.... oh well i guess i can light my fireplace with these dyno sheets





Greg
 

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Discussion Starter #7
The numbers were real. I made about 5-6 pulls and only posted 2. I was standing at the window coaching the operator with how to make the pull. We did not have a Tech II, but it was made with throttle roll in, 4th gear acheived, and then full throttle from about 2000 to 3500. I have a feeling that the torque would have peaked sooner if we had been able to start the pull at a lower RPM. We discarded all of the runs that included a shift and also 2 that were made in 3rd gear. I have been around dynos for a long time and they were valid pulls. There were a couple of the Ford boys that allowed the trucks to shift and just stomped it from a stand still. They were not valid runs. I stand behind the numbers. If you were to look at the curves on the plots, then you would also see that it looks like a valid pull. They were using an optical sensor to read the crank pully so there was no problem there. Look at the jump between the the stacks and you will see what I mean. Happy to post the dyno plot.


Jess
 

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jesshd said:
We did not have a Tech II, but it was made with throttle roll in, 4th gear acheived, and then full throttle from about 2000 to 3500.

Jess, will you educate me on how you do this? This would be good information for this old dyno operator.


jesshd said:
I have a feeling that the torque would have peaked sooner if we had been able to start the pull at a lower RPM.

Your feeling is most likely correct. Being able to pull one of these trucks from 1400 and up will typically yield a higher torque number.


jesshd said:
We discarded all of the runs that included a shift and also 2 that were made in 3rd gear. I have been around dynos for a long time and they were valid pulls.

That is what I do as well. The only time they may be valid is if the true peak of the curve is higher than the spike. But in most cases, I toss them too.


jesshd said:
There were a couple of the Ford boys that allowed the trucks to shift and just stomped it from a stand still. They were not valid runs.

These are not valid for peak numbers and you cannot graph by RPM in this case. But this is one of the ways you can make a dyno run.


jesshd said:
I stand behind the numbers. If you were to look at the curves on the plots, then you would also see that it looks like a valid pull. They were using an optical sensor to read the crank pully so there was no problem there. Look at the jump between the the stacks and you will see what I mean. Happy to post the dyno plot.

Was this a Dyno Jet? If so, do they run many diesel trucks?





Thanks
 

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Discussion Starter #9
It was a Dynojet. We locked out overdrive and ran in tow/haul. Then just let the truck keep shifting until it was in 4th, let the rpm drop to about 2000 (going lower would cause a downshift to 3rd) while still maintaining some pressure on the foot feed, then give it to it. The trick was to keep it above 2000 and keep some load on the pedal when letting some RPM off. If you just took your foot off the pedal, then it would down shift.


Jess
 

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Jess,


My 5th gear runs with Juice / Predator stack yielded: 446.7 HP and 849.8 TQ from the DynoJet. Interesting to note that the HP is almost identical but the torque is up about 70 lb/ft.
 

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Jess I lost my post in response to this.


Ok lets say a stock truck puts out 235-245hp. Add in juice, which is worth a few more hp than advertised. Add in the 120hp Predator, which when we dynoed it (100hp version) wasnt worth 100hp alone. So 90hp+120=210 add that to a stock number 245=455 ten horse more than what you got. My dyno run, stacked with Juice L4+Pred 40hp only got me 350hp,644tq. My dyno run with L4+Pred100hp only netted me 15 more hp and 22 ft-lbs. almost 100hp lower, and 112 ft lbs lower.


Now what I dont get is when stacking two pulse on pulse boxes, alot gets lost, theirs only I guess so much you can get as shown by only 15hp-22tq difference when jumping up the Pred 60 hp. Mackin Dynoed at lower number with that running Comp Juice and propane. Now GMCTRUCK took a run with his truck....Running his truck in 4th gear got him 728 ft lbs...running it in 6th gear got him 200ft-lbs more 920. With the same setup


Im not calling you a liar, And Im not trying to start and arguement, but those numbers arent accurate, tangible number. In CT we dynoed same trucks on 2 different DJ dyno's and only found a 10hp difference between the two. Either the run wasnt in 4th gear, or the Dyno operator isnt doing something right.


Maybe Im wrong, Maybe Im not, Just doesnt add up in my eyes. Maybe someone with more experience could add in on this


Bill


Guys stacking the Quad 210+CompJuice+propane got 40 more hp and 100 ft-lbs more, with a much better stacking setup.
 

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Discussion Starter #12
Smokin Deezul said:
we dyno'd in 4th gear tow haul locked in and achieved those numbers i gained a bunch more hp today dyno proven 3 pulls but whats it matter if I am not doing it right i guess 3 runs between 501 and 505 hp and torque between 929 and 935 are bunk numbers.... oh well i guess i can light my fireplace with these dyno sheets





Greg




Greg,


Can you elaborate a bit more on what you had stacked and what kind of dyno you did this on? Was it a local dyno in Ft. Collins?


Jess
 

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Here we go again... Funny how the Ford owners on the other site were commenting on how accurate their numbers were... Maybe the dyno jet just likes Fords and gives them accurate readings and inflates ours so us GMers dyno higher to meake 'em look bad at their own event. We were all there counting the shifts as each dmax made their run. We would know and the dyno guys would know when it wasn't in fourth or would downshift on a run. After that run, it was deleted because we knew it wasn't accurate and run again. Jess, maybe you should have done two runs with the stack to see if it was almost identical like my run was. Seems everyone is a liar these days if the person questioning the results wasn't there...

Here we go with another GotJuice episode...


It is possible the numbers are high, I thought my run with Juice on level 0 with a 4" exhaust was a little high at 302 hp, but no one seems to question that.. I never expected 375hp from the 90 juice and 4" exhaust, but no one questioned that. Is that inline?? I don't know, some vendors claim up to 20-30hp increase with a 4" exhaust system alone. If my run is ok, then the dyno operator knows what he is doing, because he ran Jess's truck the same way!!


At this point I cannot believe that I could get better numbers with 90 juice and 4" exhaust then Bill got with his stack, Juice L4+Pred 40hp that got him 350hp,644tq.


Is it possible the different altitudes make a difference, or outside air temperatures??? I duno. But the truck WAS in 4th gear for the run. Maybe you should come out to Colorado to dyno your truck so your numbers will be higher??



Bob
 

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I think I pulled mid 340's with kennedy exhaust, uni filter in the stock box, and juice set on 90. I made the runs same as you.....OD locked out in TH. This was on a dynojet when I had 5000 on my 03. It did take some coaching of the operator....finally got a few consistent runs. Only got a hair over 600lb/ft, I figured I would have made better than that.
They had the optic sensor hooked up.


Might have to take her back when I get my attitude adjustment



Being juiceless sux
 

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I think you first need to understand how a DJ measures power and then it will become clear why the difference in the readings. When your on a DJ you are accelerating a fixed load of app. 1500 lbs.( each dyno is different as to the exact weight), this is the mass of the drum that the trucks tires are in contact with. The computer measures the rate at which you accelerate the drum and calculates HP and Torque from that. There is no direct measurement being done. If you run in different gears you will accelerate the drum at different rates thus different HP outputs. So if one truck has 3.73 axle and the other truck has a 4.10 axle with the same engine power output the 4.10 axle truck will always show a lower Hp output on a DJ when in truth they are makeing the same power. So anything you do to change the gear ratio affects the readings. I have personally seen people inflate tires to unsafe pressures and redyno and pickup 20 Hp on a DJ!


The second problem comes in when the computer applies the correction factors. The SAE correction they use is for a non boosted application only! It assume and engine effecincy of 85% which is about right for a NA application. A typical Dmax under boost is really app. 125%, and then there's the air temperature correction. The DJ computer measures room temperature and assume that's intake temperature which in the case of a turbocharged engine is far from the truth.





So what a DJ run is good for is compairing before and after results from adding a product, if the numbers increased then you've gone the right direction..............the numbers themselves are somewhat meaningless.
 

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Discussion Starter #16
I understand how dynojets work. I have over 100 pulls on my other car and probably another 100 on other cars. I know when the output graphs look bogus and when they look right. I can post the dyno plot if you want to see it. You can tell from that which was the good pulls. I am not going to debate this to death. Yes it does depend on correction factor for temp, humidity and altitude. Typically the correction factor for this altitude on a turbo vehicle is about 20%. All of the Ford trucks were pulling within 10-20 hp of what they dyno'd in the summer when they were on a Mustang dyno with "Dynojet" correction applied. Yes, the Dynojest reads higher. Yes it is really only meaningful for the owner if they make mods and do a before and after pull with the mods on. Nothing to disagree about there. The ops here knew what they were doing, and the pulls were valid. The dynojest measures the amount of time it takes to accelerate the drum mass to a given speed. Higher or lower gear ratios do not matter. If the gear ratio is lower, then the upper speed will be less. If the gear ratios higher, then the terminal speed will be higher. Otherwise the dyno would not be able to calculate for running in 3rd vs 4th gear. The readings will be different. That is why the accepted way to get "valid" or comparable numbers is to run the vehicle in a 1 to 1 gear. Every dyno will read different. The best comparison is uncorrected numbers.


Jess
 

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I guess its our turn in the Barrell! Jess I went to Redline Performance here in Fort Collins its just kind of around the corner from my house off of Timberline and Drake. Very nice place and very nice people who run it if we can get 20 trucks for a dyno day the cost is 40 bucks a truck for 3 pulls. As far as stacks goes it was V/A on the big setting and the quad on 90HP. I tried the va on the big setting and the quad on 135 and the truck started the bursting really bad way too much timing from the stacks. I have dyno'd on load dyno's I have dyno'd on dyno jet's me personal opinion is the the both of them do a great job and from what I have seen and granted this was on my Powerstroke that the reading were within 6HP from each other looking at the charts in front of me and the mustang was 6 more HP than the dyno jet. I like the dyno jet a shade better because there are more dynojet's around here than mustang dyno's. now as far as gear ratio and airing the tires up i wouldnt know my truck has 60 psi in all 4 tires. I dont see how that could make a difference and really dont care. I believe the number's I made with out a correction factor monday afternoon. Problem is the same set up I had on saturday was with in 3HP and 7Ft lbs. so I figure its pretty accurate. but what do I know.... Aparrently dyno's lie!





GregEdited by: Smokin Deezul
 

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I think what we are missing is how you stacked two pulse on pulse boxes and netted max hp from both boxes stacked. And if a dynojet measures the way you say it does,"we should be closer"(ie you and i)


Ratlover you should have come around to say 340ish and 650??? torqueish. A comp juice box put down in my truck 386hp 724tq. Another truck same combo, I beat him by 3 hp, 8ft lbs tq.


Im not really saying dyno numbers, well yeah I am, I guess. Pred and even Hot Juice you shouldnt of even broke the 405hp mark and even come close to 740tq. A built truck with a done up tranny cant even brake 450hp with out stacking 2 boxes and adding LP on top, been their saw that.


I guess your the expert taking 100 dyno runs, but anyone stacking pulse on pulse knows those #'s are unreal.......


Uncorrected numbers, you are right...if anyone got the numbers you got....we would all say F lp, and F hot juice...stack Pred with reg Juice....Everyone in CT would be dyno kings, But we werent, even by 100 hp and 80 ft lbs by which we were off from in your set in gold number.....I think its BS, I think if you and me and anyone ran on the same dyno...your #s would be 375-400 and 700-725....MAX.....I bet even lower


Its just my guess... If Tony read this he could give his expertise.......he took 10 runs stacking HJ,Pred, Pressure box......didnt break the 750 mark...F-it MACKIN running a special comp juice, quad210, and Lp.......Only beat you by a small amount...well yeah within a 3 digit number . All Im saying is 120+90 Pulse on Pulse will not even come close to making 445,


BS


Bill


Id say youd have a hard time breaking 405 running that stack....Id even give ya 420 before Id call Shananagins on it....Im just a dick.......Ive seen 15 Dmaxes take a collective number of 200 dyno runs....I even seen 1 truck take 29 runs one day. Its bogus...same dyno company Id expect a 15 hp 25 tq diff....MAX


Bill..... call me a jerk whatever, I dont believe those #'s......
 

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Discussion Starter #19
Not saying you are wrong. That is why it is called debate. Just bear in mind that there were 10 or more Ford trucks that made pulls along with several Dodges. They all were within 10-20% of what they saw on the other dyno when they had their dyno day in August. If there were over 20 trucks and most of them had dyno'd before, then if there was a major discrepency with the numbers, they would have said so. Go to www.dynopro.com and check the business out. I think that it will help you see that they are very reputable. With the jump that I got in HP and TQ when stacking, then you can see, whether or not you believe the end number, that the difference was about what it should be. Not trying to say anyone is wrong or right, but there is enough comparison with other trucks on other dynos that this dyno is on target with what the other people ran on other dynos. Gregs numbers are very very similar to what he ran at another location on another day. There are just way to many similar results to call BS just because there is a difference. Ultimately, it all boils down to having been there and done that. Your experience was different than ours, but who is to say that the dyno that you ran on wasn't reading very low? Have you dyno'd on other dynos? Would love to know what your trucks and stacks did when run at another location and on a different dyno. I would be willing to get with Greg and run my truck on the dyno in Ft Collins that he ran on later just to see what the difference is. Besides, it is fun!!





Jess
 

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Hey Jess, don't sweat it. I have one of those bogus BS fake HP trucks too. All I have heard from the CT dyno guys is that every other dyno in the country reads high and we are a bunch of BS'ers.


My truck may not make the same numbers on another dyno, that is a given. I do know that I have used the dyno to verify the advertised gain on my mods and some give even more than advertised.


All in all is sounds like a bunch of whining and it's putting off a lot of guys from seeing ANY value from a dyno run which I think is the real BS.
 
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