more on our duramax... empty

[Mark_Kendrick]

Re: "JUICED"

Originally posted by MACKIN

rdanley,

Well,... .

Not because I need to or have to... ... . My D-MAX ran strong to So I guess I just wanted to... ... Not to mention there is some pretty fast BOMBED Cummins in my area... ... . I didn't want to be denied the thrill of owning a DIESEL to be reckoned with... ...

That's it... .....

MAC



Courtesy OF THE TDP>>>>>>>Did you happen to see the dyno run #'s that the D-MAXES ran at BD's Dyno Day this past weekend? One GENT put down 358 Hp with a 120 VA BOX and a Kiss of cooking gas, not to bad..... HEADS IN TACT. . He needs some transmission upgrades..... I was one to think the Allison would not need it, Friggen GM... ..... I guess the never expected us to need 400+ HORSE'S... . LOL

My little '01 Mule runs like a , to quote a tdr member, 'recently violated primate'



I spent alot more than $650 but my truck broke the tires loose on the Cummins Southern Plains dyno at 377hp. no TQ rating because of a lack of tach input (rpm was about 2800rpm).



they could not pull my truck below 2600 rpm in 6th gear. It just smoked the tires.



The tech estimated 470hp at the crank that was measured and guessed that 430+hp at the tires was believable.



I'll have my new cam in a few days and my showerheads with it(injectors for those bowtie folks)



I expect to hit near 550hp at the tires(#2 only) on a dynojet and will have a nice pretty graph to show off.



A chip/box is hardly considered bombed and that goes for Dodge Ford and Chevy. Gimme a yell when anyone with a street driven maxipad hits 450rwhp on #2.



there are some fast Fords around running propane and nitrous and swapping head gaskets like pairs of socks. HighPerf360 on this board has a stock engine and turbo running low 13s and whippin on souped WRXs. . he uses nitrous too.



A few of the sled pullin crowd are running 800+hp out of high revin' 12Vs.



The Duramax will have a long road to travel beore it comes anywhere near the power and durability of a CTD.



I'll drag you and your trailer up any grade faster than you can pull it... Mine won't quit at 100mph



You have a nice truck but the Dmax ain't got a thing on a CTD.



Don't take it as a personal attack. The Dmax and PSD are clearly outclassed by the CTD.

 

[Gary - K7GLD]

SO, Mark, are ya sayin ya LIKE yer Dodge?

 

[Mark_Kendrick]

Gary,

you ARE an astute observer

 

[Jeff H]

Don't pay any attension too this!

YA know I was at one of them there tractor pulls last year. Would ya believe there were even diesel pickups in the pull. All were stock. Not even an ounce of smoke. A couple of Fords and a zuzu max with the allison. If I had to chose between the Ford and GM. Ford wins hands down. The Ford is heavier and was able to spin all four. The zuzu had no tire spin and came up short against the Ford. Don't give the lecture about how the ford was heavier line. If you are lighter in weight it should be spinning the tires faster. No body showed in a Dodge. So maybe next time hopefully some one will show up in a Dodge. Oo.

 

[rdanley]

wanted to hear about a ctd out pulling a d-max

well mackin i see were your mind was at being on that juice an all. you did not read my last thread from the start. i took two of them out going up the same grade. bone stock :--)

 

[JoeyD]

rdanley, That is a funny story, but it is just that a story. It's funny how you happened to pass 2 of them on the same hill. That truck would pull 6k up a 6% grade with ease, just as any of them would. TDP ran a 10K trailer up a 6%grade last year and it would run it at over 60mph. The stock Dodge wouldn't come close.

In the future please make you fairy tales more believable, Thanks.

 

[SLightfoot]

But they'll be behind me...

Originally posted by jdecampo

rdanley, That is a funny story, but it is just that a story. It's funny how you happened to pass 2 of them on the same hill. That truck would pull 6k up a 6% grade with ease, just as any of them would. TDP ran a 10K trailer up a 6%grade last year and it would run it at over 60mph. The stock Dodge wouldn't come close.

In the future please make you fairy tales more believable, Thanks.

I can tell you one thing. The D-Max that I meet on the hills I can assure you without a doubt, will be BEHIND me, with distance growing.



Even if the DMax is juiced..... still behind.



The thing I hate most is some guy slowin' me up on the hills.

 

[JoeyD]

Shawn, I am not saying that the GM is the best puller no matter what, but for someone to say that their stock Cummins pulling double the weight as a stock GM get real. The same would be true if the trucks were reversed.

 

[rdanley]

FAIRY TALES

WELL JD I WOULD HATE TO BURST YOUR BUBBLE BUT IT IS TRUE STORY, NOW MAYBE THEY WERE HAVING ENGINE TROUBLES BUT THAT WOULD BE STRANGE BOTH OF THEM TOGEATHER HAVING TROUBLES. I WOULD EXPECT NOT. BUT I WILL TELL YA ONE THING WHEN I GOT MY 99 CTD IT WAS A FAIRY TALE, IT CAME RIGHT OUT OF THE BOX BEING A RABID APE.

 

[JoeyD]

SURE IT CAN

 

[Cummins4Life]

LOL Oo.

 

[DiTrani]

Little Reality

Guys, while I agree that the long-stroke I6 design is inherently a better motor for pulling heavy, numbers don' t lie. If you have a DMax pulling a n0,000 # trailer and a CTD pulling the same up the same hill, if the DMax is rated at 300 hp and the CTD is rated at 245 hp, the only way the CTD is going to out pull the DMax is if the DMax doesn't have an gear available to let it use the power, which might be the reason some DMax truck _reportedly_ don't pull well. Any engine spinning up 300 hp can out pull an engine only spinning up 245, regardless of design or torque curves.



Assuming similar displacements, the long stroke I6 offers different power delivery characteristics (big torque at low RPM) that make it easier to pull heavy loads, but there's no mystical advantage that allows the I6 to out gun a V8 that's making more hp.

 

[Mark_Kendrick]

very few V8s have more power than my I6.



but I don't have a mere 245hp



HP determines the speed at which you will top out under a given load. Torque determines how fast you will accelerate it.





the Dmax and cummins have very similar gearing between a 5spd and an allison. the difference is that the cummins is gonna get the load moving a little quicker. the Dmax will move it faster on flat ground. the CTD will move it faster up hill when accelerating.



take an off the wall example... a 230hp 2300# WRX and a 540hp 3500CTD Dodge. the WRX has the advantage on the hp/lb ratio but the dodge out runs it, why? the 1200ft lb of torque its making!!!



The Dmax and the CTD make similar torque numbers but the Dmax does it at a higher rpm and higher HP level. The 12V is going to enhance this advantage because the bottom side of the RPM range is much stronger. the 24V usually have to rev a bit more due to emissions driven ECM programs.



when the CTD is turned up the the 260rwhp level the bottom end is brutal compared to a Dmax.



When my stock truck w/a PE Comp made 297rwhp it made 732 ftlb!! 100ftlb higher than the dmax at the same level.



This is a hard point to argue because there are a lot of factors involved. there is a reason the vst majority of hot-shotters drive CTDs.



The Dmax is a nice engine for light pulling and making chicks happy with your truck. When you want to come play with a man sized load get a nice, offensive, stump-pulling I6 CTD until then I'll just wait for you at the top of the grade

 

[Champane Flight]

Consider

Consider this, why can my 160hp Cummins outpull a 300hp gasser? Could it be I have 460ft lbs of TQ to his 380? Exactly!

A V-8 should and will have higher HP ratings, but when it comes to pulling? Well, the V-8 falls off RPM faster and has to take a lower gear, where the I6 hangs in there and holds an RPM. The V-8 will out acelerate the 6, but that is the only advantage. Some of the members here have even overcome that.



I have proven this with similar rigs with same HP ratings, the I6 just holds it longer. Design in diesels is everything, if you don't believe it just look at the little Cummins.

 

[Sky]

Hmm a corvette must be able to out pull me then. A viper too. Or even a porche. They all have more HP.

 

[SLightfoot]

Not true...

Originally posted by cditrani

Guys, while I agree that the long-stroke I6 design is inherently a better motor for pulling heavy, numbers don' t lie. If you have a DMax pulling a n0,000 # trailer and a CTD pulling the same up the same hill, if the DMax is rated at 300 hp and the CTD is rated at 245 hp, the only way the CTD is going to out pull the DMax is if the DMax doesn't have an gear available to let it use the power, which might be the reason some DMax truck _reportedly_ don't pull well. Any engine spinning up 300 hp can out pull an engine only spinning up 245, regardless of design or torque curves.

Not true entirely. You can have a high horsepower engine, but if you DON'T have the torque at the bottom end of your RPM curve, you won't have the twisting power to pull the engine speed up when you shift up to a next higher gear.



Take for example one of these hot-rodded rice-bucket cars. Some of them post very high HP, but this is because HP is based on RPM just as much as torque. Could the rice bucket car pull a trailer up a hill faster than our Cummins? No, because although the HP figure is there, you don't have enough gears to ALLOW the RPM to get up high enough to develop your horsepower.



Remember, HP= (Torque X RPM) / 5252.



So, torque curves are VERY important, since you need to get the top of each gear in order to pull faster. If you don't have the low end torque, you won't be able to accelerate to the top of the gear as fast, if at all.



The one exception to this rule is # of gears. If you have many many gears to work with, you can gradually overcome this defecit.



So, it's NOT just Horse Power. You need lower end torque, otherwise you can't spin the engine up to where the torque and HP peaks are.



Shawn

 

[DiTrani]

"HP determines the speed at which you will top out under a given load. Torque determines how fast you will accelerate it. "



Not really true. Torque determines how well you'll resist deceleration. For example, take 2 trucks, same load, same hill, one V8 spinning at 3500 rpm making 300 hp, other CTD (or other similarly designed engine) spinning 2400 rpm making 295 hp, both at same speed and at their HP peak. The V8 will be slowly walking away from the CTD. The CTD will obviously have more torque, so the CTD will decelerate at a smaller rate than the V8 if the grade increases, so the CTD will catch up a bit, but then the V8 will start to walk away again (assuming that the hill isn't so steep the 300 hp can't accelerate the load). If both trucks mash the throttle, the V8 will accelerate at a higher rate than the CTD (assuming it's hp curve doesn't dive too dramatically after 3500 rpm).



"take an off the wall example... a 230hp 2300# WRX and a 540hp 3500CTD Dodge. the WRX has the advantage on the hp/lb ratio but the dodge out runs it, why? the 1200ft lb of torque its making!!! "



No, because it reaches it's hp peak so much more quickly than a short stroke gasser.



But like I said, there are certainly factors that make the CTD a better pulling engine. I'm just trying to debunk some bad science that gets thrown around here.



"Consider this, why can my 160hp Cummins outpull a 300hp gasser? Could it be I have 460ft lbs of TQ to his 380? Exactly! "



Strictly speaking, it can't. Your truck would be a much better pulling truck, but if he's got a gear that lets him spin at his hp peak going the same speed as you at your hp peak, he's gonna out pull you.



"Hmm a corvette must be able to out pull me then. A viper too. Or even a porche. They all have more HP. "



Assuming the things wouldn't fall apart, than my previous paragraph applies to this as well. Will the right gearing, under strict circumstances, they'd out pull you. Wouldn't be fun though!



"You can have a high horsepower engine, but if you DON'T have the torque at the bottom end of your RPM curve, you won't have the twisting power to pull the engine speed up when you shift up to a next higher gear. "



This statement is true. This is why the CTD is a much more friendly pulling engine. This is what I was talking about when I said that the CTD has characteristics that make it a better hauler. But the difference between the V8 diesels and CTD torque and hp curves isn't so drastic that you'd find yourself unable to get to your hp peak while a lower hp CTD can. At least it's not likely.



"So, torque curves are VERY important, since you need to get the top of each gear in order to pull faster. If you don't have the low end torque, you won't be able to accelerate to the top of the gear as fast, if at all. "



Torque curves are very important, and make the CTD a dream hauling engine. But torque doesn't accelerate you, hp does. Getting a heavy load moving with a high hp gasser is miserable. You'd spin the clutch like mad since you have no torque down low to resist the load and no hp down low to accelerate it. But if you had a transmission that allowed it to spin up to hp peak, stay there, and vary the ratio so that peak power always went to the wheel, it'd would accelerate the load like crazy.



I should have written my first post more carefully - like I said, I'm just trying to debunk some of the voodoo. Assuming that the published power/torque specs for the CTD and DMax are the correct, or more likely similarly incorrect, with the same transmission the stock DMax will out pull the stock CTD, up or down a hill, with or without a load. The Allison might not let it do that, however.

 

[SLightfoot]

Originally posted by cditrani

"But torque doesn't accelerate you, hp does.

Wrong. Torque acclerates you.

Remember that torque is ONLY a calculated figure from torque and RPM.



Here is a good website that describes torque and horsepower:



http://www.vettenet.org/torquehp.html



Read "The Case for Torque".



Shawn

 

[DiTrani]

Originally posted by Shawn. L. Turbo





Wrong. Torque acclerates you.

Remember that torque is ONLY a calculated figure from torque and RPM.



Here is a good website that describes torque and horsepower:



http://www.vettenet.org/torquehp.html



Read "The Case for Torque".



Shawn

I respectfully disagree. hp is calculated from torque and rpm because that is the only practical way to measure it with a dyno. hp is a measure of how much work is being done. It's work that accelerates you.



Put a wrench on stuck bolt. Apply 10 #' of torque. It's till stuck, so it doesn't move. You are applying 10 #' of torque, but you aren't accelerating anything. You aren't doing any work.



I've read the article you cited, and it doesn't dispute anything I've said. This is subtle stuff, and it took me several years as a physics major before I really got it.

 

[Mark_Kendrick]

Originally posted by Shawn. L. Turbo





Wrong. Torque acclerates you.

Remember that torque is ONLY a calculated figure from torque and RPM.



Here is a good website that describes torque and horsepower:



http://www.vettenet.org/torquehp.html



Read "The Case for Torque".



Shawn

I think he meant HP is is only a calculated from torque and RPM.



I've driven SB chevys that had more HP at 3500-4000 rpm than we do and when they're running at that sweet spot they don't pull as well.



the low rpm torque does matter more than HP.



Most bog rigs have crank hp ratings of under 450hp yet they pull 80,000+lbs.



they do it by making 450hp at 1500rpm



(450/1500)5252=1575 ftlbs!!!



They have all the gears not because they need them to accelerate the load but because of the very narrow operating ranges of the engines.



their top gear ratios are very similar to ours. . usually in the . 7x range.



HP determines top speed in the 1/4. torque has a much greater effect on ET.



Big blocks usually don't make much more hp than small blocks but they often double the torque making them a better motor to pull you to the finish line.

I'm just trying to debunk some bad science that gets thrown around here.

Go ahead. . try my science is not bad. There are distinct advantages that are not obvious on paper. the factors by which the figures from the pencil vary do not do the difference in real world performance justice.