I'll agree with that. I recently saw what lays underneith the hood of a late model GMC and it was so jam packed in there I couldn't even hardly find the turbo. :doah: I have lots of spare room under the hood of my Ram.
Well, I will still stick by my original post.....The torque of the CTD has much shorter slope to peak torque than the Dmax and is therefore flatter....That graph is NOT condusive to a properly bombed 12v.....As far as losing higher end torque, this is very easily changed on 12v compared the 600 CR - they can rev quite high if you like.....but one of the nice things about having all that torque right at your highway cruising rpm is that, unlike the V8's, you often don't have to down shift (or not nearly as often) to maintain speed on a grade as OD already puts you in the fattest part of your curve.....the V8's typically have to down shift to get them back into the fattest part of their curve. I have very little experience with the CR CTD but I can tell you the Cummins engineers are working hard to keep the torque curve DOWN! and they are bumping the hp up by simply adding high end rpm......it is interesting to note that a typical 12v pumping 325 hp is making close to 800 ft/lbs of torque! Bump it up to around 400 hp and it will generate between 950 - 1000 ft/lbs....This is normal and easily done with a 12v CTD on a tight budget. My point is if you peak at 800 ft/lbs, do you really care that it falls off to 725 ft/lbs at your hp peak?.....I would think not! The seat of the pants perception is that the curve does not fall off regardless of what the dyno # is..... All this is, as it has been mentioned is preference.....does the Dmax tow well? - of course it does!...but the poll asked what do you think is the BEST motor for towing a grade and my opinion is that it is a 12v CTD....
IMG]Rod and piston comparo[/IMG] This pic shows the differences between rods and pistons....the rods are self-explanatory - another reason why the CTD is designed in the true medium/heavy truck engine fashon for generating large torque #'s and having unmatched longevetiy.... The pistons also tell a story.....notice the very long, full skirt on the CTD piston - a typical diesel piston that virtually eliminates the piston rocking/slapping in the bore which promotes long ring life and excellent sealing. The V8 skirts must be heavily clearanced to accomadate the much shorter rod (poor rod ratio) and tighter crank clearance.....durability suffers as a result.
Im so damn sick of that picture. It shows absolutely nothing, and heres why. The ISB has a displacement of 360 cubic inches, rounded up for the sake of simplicity from 359.5. The 6.0 PSD is 366 cubic inches, and the Duramax is roughly 402. The ISB displaces 60 cubic inches per cylinder, the PSD 45.75 and the Duramax 50.3. Hmm, what do you know, the ISB displaces signifigantly more per cylinder, so it has more stress on it every cycle. The PSD and Duarmax have it spread out more, with less stress on each connecting rod, so why in the hell would they need a rod the same size as the ISB? Second, it only shows the rods from one view. What it doesnt show is how much thinner the PSD rod is than the duramax and ISB, or that the PSD rod has a much shallower and less pronounced I to it. Durability suffering because of the piston design? There are way more powerstrokes out there in pickup trucks than there are cummins, and they hold up just as well. Dont forget that the T444E and T366E's were designed and built as a medium duty engine as well, and get worked in the medium duty world just as hard as the 6bt/ISB. The powerstrokes are damn good motors, and have proven themselves as such. Its not International's fault ford cant work a computer and screwed the 6.0's up. No, they dont lend themselves to bombing as well as the 6bt's do, but so what? They dont have stupidly oversized injection pumps like the 6bt's with the P7100's do, so they are limited by fuel delivery. All that picture is good for is making Dodge owners feel better about themselves because their rod is bigger. Never mind that it HAS to be bigger due to more stress on each rod. Dont get me wrong, the cummins is a great motor, i still plan on swapping a Cummins into my bowtie, but that pic is just plain stupid to use as an argument as to why yours is better.
Interesting perspective and I see your point but the extra load the piston and rod have to manage on the CTD is not proportional to the difference in strength and bearing surface area.....also, even though the stroke is longer on the CTD, the rod lengths are still not proportional to each other in relation to the stroke - the CTD still manages a better rod ratio.....and since we are arguing about bottom end strength I prefer to have 7 huge main bearings supporting 6 cylinders....having a individual rod journal for each rod is much better than having one rod journal sharing 2 rods.....each rod journal on the CTD holds the load and reciprocating mass of only 1 rod and piston, though heavier, it is still much less weight.
I have to agree with Joez, that picture is worthless. A 6 cylinder engine is going to have bigger pistons and rods than an 8 cylinder engine of the same size. :doah: Why a 12v? From what I have found, the ONLY place a 12v engine accells in is that it has a P7100 pump. Besides that what makes it so great? The later 24v ISB has a better turbo, better head, improved durability to the block, and centered injectors. Of course the 12v rules at the extreme end of diesel performance but for most of us that want to make moderate power numbers I would say the 24v version wins hands down. A bad VP44 you say? Add a F.A.S.S. system to a fresh VP44 and no worries with moderate power numbers( were talking up to 500HP or so) and the best part is the ability to turn down power and adjust it on the fly. 12v's are great at the strip and at the pulls....but give me a 24v anyday for REAL day in and day out driving so I can simply "turn" the power on when I want it. waytogo Oh yeah, Cops just love a bombed 12v's....all they have to do is follow the smoke. :doah:
The graphs of "bombed" CTD or DMax engines varies, which is why I limited my discussion to "stock". Even though many of us do "turn up the wick", most do not due to lack of knowledge, interest, or fear of warranty issues. Due to all the different curves and trade offs, I think limiting to stock is reasonable unless someone wants to post a good selection of the possible dyno graphs for us to compare and contrast. Otherwise, any discussion of "bombed" curves is just words since I can't remember the details of what I have seen, much less what I have not. I believe I already stated that, at least for the DMax, the "fattest part of the curve" is right at or below my interstate cruising speed of 75(ish) which does work rather well. However, if it were not Interstate speeds then yes, I would need to down shift where a Cummins might well torque on through. But that really does not change my very first statement. For a multi-use vehicle I feel the DMax wins, but if all I had to do was tow heavy or pull the hypothetical grade mentioned in the thread topic, then I would go with CTD. I don't dispute you on that point, but rather on some of your choices (including poor choice of words that were IMO misleading) for supporting your point. I'm not CTD expert, but from what I've read and what I've been told by CTD aficionados who do it, this is also not true. Well, actually it would be more accurate to say that it is not possible based on how most of us would define "tight budget". I could say more but it would be pure "hear say" so I'll leave it at that, and obviously I could be wrong since what I already said was just "hear say" too. I won't even get into that picture. Joe has already covered that better than I would have. waytogo But I will also agree that the CTD clearly has the stronger bottom end and a clear history of excellent longevity. Anyway, take care. And don't take this personal, I love a good debate, as long as it's in the right forum. rotfl
No, no...I would never take this personally....I would only reserve this type of "discussion" to this forum, though.....I like a good debate too!....I always end up learning something about the "other" guys diesels! ....... As far as not believing the torque #'s, well, most guys that don't own CTD's tend not to believe it....as far as CTD aficiondos go, you are talking to one now and while those hp vs torque #'s seem high, it is quite doable with a 12v.....24v's are another story - you typically don't see 1000 ft/lbs until about 475 hp...This is because torque and hp peaks occur higher in the curve on a 24v than a 12v. If you want to see a 450 hp 12v CTD built on a tight budget, then look at the 94 in my sig....it weighs 6680 lbs with me in it and runs a 14.0 @ 101 mph - just got to the track last weekend.....no dyno #'s but if you do the calculations for hp with weight and mph and/or ET you'll see it makes over 450 hp, though I don't think with my particular setup that it actually does.... 24v's have a better cylinder head?...Why, because there are 2 more valves? Flow bench #'s would indicate that a 12v flows better.....that said, the 24v head is hardly a limiting factor for power, but yes, the pump is the limiting factor.....is it easier to make big torque with the 24v?...Yes....Is it more exspensive to do so?...Yes....If you are on a budget the 12v will cost considerably less to pump up.....I have done it. I like 24v's too...I have one of each, so I feel I can make some accurate comparisons in their performance and what it takes to make specific power #'s. Adding a $600 fuel lift pump (FASS) makes the VP44 as reliable as a P7100? ....I will have to disagree with that statement.....The VP has several other reliability issues other than worrying about maintaining a certain injector pump inlet pressure!....98-02 2nd gen 24v's have the SAME 12cm HX35's that the 12v's did (other than the 00-02 autos with the little 9cm HY35) - what makes the 24v turbo better when they are identical? The VP is a good IP but if you are suggesting that it is as reliable and tunable as a P7100, you are wrong. As for day to day driving, my 12v drives just as well as my 24v.....and as far as cops go, I guess you are not aware of the valet switch that is installed in the AFC on the P7100 that will cut the power back at the flip of a switch......besides, a bombed 24v pumps out just as much black smoke if the fueling has been set up accodingly. BTW, BadDog, what was my poor choice of words?......I'm certainly not intentionally trying to be misleading to make my point.
Sorry to be so long replying, I've been on conference calls all day and while I did read a bit, I couldn't dedicate much brain power to replying coherently. As I said earlier, depends on what "tight budget" means. To me that means well under $1k for "toys". And I don't think you can get those numbers and remain dependable even on a 12V without some significant coin, though I'm totally prepared to be wrong. However, low 14 second times are totally possible (according to reports) on a 7500 lb CC DMax with nothing more than a "Hot Juice" or "200VA" (or a little more change for a TST box, but trying to stay sub $1k here) a straight pipe (or straight through high-flow muffler). Total cost around $500-$700max unless I'm wrong about current pricing. And to make the Allison live under that day in and day out, a Transgo kit with your choice of single clutch converters. Not only would the CTD require more to get to that level (talking 12V or 24V here, although the 600 seems to respond to the box as well or better than the DMax), but the auto trans will need more than just a shift kit and converter. Of course that's on the strip, not towing, but those mods (within reason) also provide dependable tow rigs capable of a wide variety of fun and function. I gotta say though, I do believe that the 12V would be my choice for performance for the reasons listed, but I surely wouldn't turn down a 24V for multi-purpose use, and I can't get over that Edge graph of the 600, I had no idea it was responding so well. Oh, another thing. Can anyone easily provide torque curves for the later stock 12V and 24V engines? I seem to remember them being much more "peaky" and also peaking at a lower rpm than the stock curve shown for the 600. I swear I recall a fairly dramatic peak around 1800-1900 with a fairly sharp fall off beyond something like 2400 rpm for those, but maybe my memory is exaggerating it. <shrug> Same for the LB7, maybe even including Edge "chip" curves too. After further thought I do seem to recall that people were saying that the chips on the LLY were typically providing higher peak power but more fall off than the LB7s. Basically, I don't recall the chipped curves falling off quite that badly when I was comparing the various boxes when I bought "The Juice". Again, maybe it's just "old age"… And finally, the "poor choice of words" was specifically refereeing to the statement of the CTD having a "flatter torque curve". Because different mods can result in quite different shapes and numbers on the curves, sacrificing peak for width and such, it only makes sense to consider stock IMO. And the stock CTD curve is anything but "flat" by any reasonable definition that I can see. It climbs rather rapidly when the chart starts at 1800rpms, has a clear peak at around 2300 or so with around a 150ft/lb gain, and then begins a relatively gradual but steady descent to around 28-2900 where it turns a fair bit more sharply downward to end at around 3300 rpms with about the same torque it it had at 1800 rpms. On the other hand, the DMax starts at 1800 with only slightly less torque than the CTD 600 and a less steep slope, peaks also with a roughly 150 fl/lb gain around 2200, and the rest of the curve looks almost like someone used a ruler to draw an almost perfectly level/flat line off the right side of the chart. Even the chipped curves on the DMax are much smoother and therefore consistent, though I will concede that the chipped CTD 600 curves are much nicer in pretty much every way except maybe for drag racing (hp being torque per unit time and all that). Anyway, I was not saying you were trying to mislead or anything of the sort. It's just the use of the term "flatter" to categorize the CTD torque curve as superior to the DMax curve defies my understanding.
Yes, I do believe that the VP44 is almost, if not as reliable as a P7100 when it is kept supplied with plenty of cool fuel, with lower power numbers of course. As for the cylinder head, a 24v head holds the injector inthe center of the cylinder and I have heard that they do flwo slightly better. The turbo may be the same model as the early 24v's but my 2001 spools up MUCH faster than all the 12v trucks I have ridden in. You can't argue the tuneability factor, with just a simple box you can have 25 levels of performance at the touch of a button with a 24v electronic engine. I have never heard of some sort of valet mod switch, not even at TDR.com. Regardless, you are either in "valet" mode or are bombed at what ever the level of the truck is set at. With a 24v you could set it at basically any level you want. I'll take the adjustability over a slightly better IP pump for sure. Plus, we have a prettier valve cover. rotfl
Ok, I'll give ya the nod to the valve cover!... Valet switch kits are available from Piers, Haisley and others - not uncommon. And yes, for ease of adjustabilty, the 24v gets the nod....I would rather push a button instead of popping the hood and sliding the plate anyday! Don't know what to comment on about the turbo spool up?!?! ...I mean heck, that is why the MAD ECM is so popular on 24v's - to stop the horrible off-idle defueling that is part of the factory ECM programming and kills the chance of good spool-up!....The defuel mode is most pronounced on the 00-01's even with the little 9cm HY's on the auto's. That said, if you are riding around in a stock 160 hp 12v CTD, the spool-up is slow on them too because the level of fueling on them is so low. We are splitting hairs on the cylinder head issue here......as I said before, the head is hardly the limiting factor for the 24v but when it comes to big power you will typically see the 12v head used as there is much more room for porting and bowl blending. BadDog: I'm sure my truck would ET a bit better if I could do a 15 psi 4WD launch, but I can't without billet shafts.....If you use mph to solve for hp I suppose it could be more accurate in my case. The Dmax's are fast at the strip....I have seen the run and I gotta say (wincing as I say it) they are fast!.....They are definately a great street/strip diesel. Hp per $ they have got me beat! They seem to be the fastest box only trucks out there - Not certain, but I don't think the other diesels can say they can make 500 RWHP with box stacking only - that is very impressive....the Dmax seems to have a very good injector from stock....Torque per $, they do not have me beat.....FWIW, the mods on my 12v (not including the tranny) could be done for about $1500 if you do the work yourself.....IMO, these days, that is power on a budget... Now the torque curves.....Let me define what I mean by a flat curve: minimal slope with the majority of the line being horizontal or close to it......The graphs in this thread DO NOT represent the 12v's that I am talking about.....To me it is interesting to note that the graph starts at 1800 rpm - 1800 rpm is a typical peak torque for a 12v!....For a comparison of the torque and hp curves the graph should start at 1200 - 1300 rpm for a 12v. W have a 05 Dmax work truck and it sure does run strong for a stocker! BTW, what is the difference between the LB7 and the LLY - are those engine model designations for the Dmax?
Actually, the 200VA dynos just over 500 rwhp without stacking and so does the TST IIRC. And I don't know the price for sure, but I'm pretty sure the 200VA is well under $1k and the TST is around $1k or so.??? And that's with only a 10 minute "plug it in" job. Thanks for the info on the older CTD curves. Your description of where the peak hits is exactly what I thought, so at least I'm not totally loosing my mind. But I would love to see the the curves for the older CTDs and the LB7. And yes, LB7 is the older DMax from '01 to '03 depending on how you count the year model (manufacturer date or model truck). LLY is the newer version with injector changes and slightly higher factory rating. I seem to recall that the LB7 (which is what I have) provided better/fatter/flatter power curves on the "juice" where the LLY peaked higher but couldn't hold it (as shown in the graph). But that difference could have just been an artifact of new chip for the LLY vs. mature chip for the LB7 back then, so they may be comparable now. <shrug>
I do believe all would get the job done but the king of grunt would be my choice . I'll take mine in in-line loonnnggg stroke flavor - Cummins. A comparison of the beef in the hardware in the motor will make the others look average and the continous service duty of the Cummins is just so damn impressive ! The motor just gets better the harder it is worked......JMHO Tom
It's impressive? I hadn't noticed. I drove my neighbors 6.0 and stock it was not all that much faster than my Ram Cummins. After we put in an 80HP chip it moved, but nothing special. Personally, I'm hoping Ford uses a different diesel brand in the near future. Something besides their RPM happy V8's.
I agree the 7.3 is an all around nice engine but for all out pulling, it can't touch the cummins. :stir:
I just hauled a 3000 lb boat/trailer combo, up and down the cajon pass, and baker grade with my CTD this last memorial day weekend. All I can say is, I had to keep my foot OUT of the gas pedal to stay at 75.. and I didn't know there was anything behind me, until I looked in the rearview mirror.. I love the Cummins with my NV5600.. Scott
