| Fixed Vane vs Variable Geometry Turbochargers... |
| 09-19-2017, (Subject: Fixed Vane vs Variable Geometry Turbochargers... ) Post: #9 | |||
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RE: Timing Actuator Closing Delay (09-18-2017 )2strokeforever Wrote: Could the reduced restriction of the WG turbo be the sole contributer? (09-18-2017 )2strokeforever Wrote: ... That statement is very misleading and for most people, has been proven to be, is, and would be untrue. There are cases where there are exceptions so it will always remain a debate with 2 sides. Your post seems to follow the typical "salesmans pitch" through bent data and a skewed opinion and it misleading as a whole. it is a tactic that people who love to troll others use and will be watched closely if it continues. I was simply tempted to just delete the post but I will respond to it instead out of professional cutesy for now. I likely already know there is no reasoning with someone who is hell bend on their views if all they are here to do is troll my forum in sophisticated ways. So that is a NO, my feelings don't get hurt,.. I just don't tolerate mis-leading information masked as fact. It is no different than the stuff you find on Internet sites selling products, where the sellers are hell bent on their data and findings =,.. yet when someone else attempts it,.. it never seems to quite pan out. I reject that kind of stuff real quick around here and consider it the same as those "aligned fuel molecules" running around in fairy-dust land after you buy that gimmick product that is nothing but a magnet shoved into a piece of pipe. That being understood up front (I.E. your post is worded more as a sophisticated form of trolling more than a discussion) ... An engine close to, or under full operating loads, where it may start to reach or exceed operating capacity of one turbocharger vs another is the only places where the differences you are referring to will normally be seen. IF YOUR OWN EXPERIENCE does not match this,.. then YOU/THEY HAD SOMETHING SET WRONG when you had the VG/ smaller turbocharger on it at lower/average operating load torque levels. I know of several people who HAVE switched from VG turbochargers that were dialed in correctly and VERY EFFICIENT ALREADY! to non-VG turbochargers and every bit of what they do that is not under higher torque/power loads were measurably LESS EFFICIENT!. - Every one of them LOST fuel mileage on average under varying load conditions, though some of them got their trucks very close after much tweaking. The problem is that when they got them really close, a loss in engine response at lower rpm ranges resulted. The only way to overcome lag wioth no control of the turbo is to add excess fuel to push it along at low rpm. There is no longer the option to adjust positive pressure (no more VG), and when doing this. Adjusting the enigne to provide a better response produces unburnt fuel to go along with that better response. I. E. -- less efficiency until it can catch up to itself again or get up to a region in rpm range where it can be overcome. The bigger the turbocharger, the more of a problem. It is because it takes more positive flow to get it spooled up. Its efficiency ratio (like in that chart you provided) is a direct reflection of this and you can see it fall off sharply at the bottom end unlike the smaller turbo's. I.E. -- One size can never fit all. Not everyone is hell bent on making 600+hp out of their engines and having to apply it to the road for long durations. For those that do,.. I am not in complete disagreement they alternatives may work better for them when using their equipment in these ways, or taking it outside of factory designs,.. but to profess such things in a lesser context as a blanketed statement is outright wrong and nothing but a sales-pitch. If your statement here was even slightly correct then there would be no way in hell that my own truck WITH ITS HE551VE VG TURBOCHARGER would have gotten the 8.3 mpg to the fuel pump 2 days ago between Seattle, Wa and Chatanooga, Tn loaded 79,960 lbs gross with a load of onions!, running it at 58-60 mph. Hell, even the scale house in Wa said I was at 33,997 lb on the back tandems of the trailer. (09-18-2017 )2strokeforever Wrote: The he551 compressor is too small for full load, running too hard for good efficiency... The hx60 is bigger and At 600hp factory torque curve, AT OR CLOSE TO FULL OPERATING LOAD ONLY, the HX60's higher flow capacity will match, and even could possibly outshine a 551VE, but only by small amounts. they did design it to handle a wider range of rpm than other brands, and it is a good match to a 15 litre ISX, but to claim it is more efficient overall is a lie. in a limited range of rpm, and only in its "sweet spot" as you have put it. Not because the 551 is too small for the job. -- Problem is,.. most people who haul freight on the highways DON'T OPERATE THEM AT FULL/HIGH OPERATING LOAD FOR HOURS ON END!. They drive down the roads at 28-38% operating loads long term and at a wide range of operating rpm and torque. This totally negates any slight gains on the upper end that one would see. Your statements are consistent with someone who only tortures their equipment with high operating loads consistently, and this forum is NOT about power and all the crap thinking that goes with it. That is why I disagree. This forum is about saving money, and making a profit with your equipment, not butchering, torturing, and adding power + all the crap that goes with it. (09-18-2017 )2strokeforever Wrote: ... It seems to be exactly that.. unfortunately, a limited view. - What makes efficient combustion is the proper final crank angle(angle of peak cylinder pressure), the proper fuel air mixture and homogenization of that mix, its volatility, the proper oxygen level, and its burn length. The "air" (charge flow) has a proper "Q" (quiescent point) in all torque ranges and rpm ranges and in a turbocharged diesel engine, it is always a positive pressure value (meaning some slight assist in positive pressure) through all those ranges needs to occur. It is not a car engine that simply uses boost on occasion to overcome its vacuum at the intake. How much positive pressure is a delicate balance. Believe me,.. I spent several years going down the roads in a multitude of driving conditions and terrain to perfect those ratios in my own equipment,.. guess what -- It would not have been possible to achieve such extreme high efficiencies if I HAD NO CONTROL OF THE TURBOCHARGER!. (09-18-2017 )2strokeforever Wrote: ... Another mostly untrue statement. IT IS IMPOSSIBLE!!! -- For ANY TURBOCHARGER WHATSOEVER!! ---- ANY!!!!--- to produce MORE POSITIVE PRESSURE than the pressure driving it!. -- If it were,.. you would be able to make a perpetual motion machine out of one and you would solve the worlds energy problems for the rest of eternity!!! Your statement HERE is SO INCORRECT IN SEVERAL WAYS it is NOT EVEN FUNNY! -- It seems to point towards sheer trolling arrogance more than anything else, hence my statements above. Here is a decent reference on turbocharger efficiency vs exhaust heat and charge flow for those who want the correct answers instead of some moron of a troll who is good at twisting words and mis-leading others ... http://www.springer.com/us/book/9783319176437 The design of a variable geometry turbocharger FIRST AND FOREMOST is for improved engine efficiency through a wider operating range vs fixed. -- YES, the ECM DOES have the ability to use it to increase back-pressure on the exhaust, but it does so at the cost of making MORE OXYGEN and excess pressure into the cylinders as it does so. It has been found that it is not until SOMEONE SCREWS UP THE EGR FLOW AND PUTS A BLOCK PLATE IN that is starts demanding the exhaust back-pressure be increased unnecessarily to force gases to the intake because it is now CONFUSED!. It will it resort to making back-pressure simply to supply the EGR circuits if it is not corrected properly. (09-18-2017 )2strokeforever Wrote: ... Where did you get this number?? 15 ltr engine @ 40 lbs boost, and moist, dense air = roughly 0.54 kg/s To get to 105, you would have to be pushing 58 lbs boost!. That or running more than 2600 RPM!. Realistically, for example, the CM2350.... 1800RPm, 33lbs boost / AT 600 HP... = roughly 0.49 kg/s. This places the He451VE right at its upper edge of recommended range according to the cummins chart you just posted. I have measured MYSELF, comparing the exhaust back-pressure sensor to the intake pressure sensor 2.8 - 2.9:1 efficiency rating of the 451VE and guess what --- IT MATCHES THE CHART YOU POSTED EXACTLY,.. PLACING IT SQUARELY IN THAT EXACT SPOT!!!. -- did they under-size it? -- NOT REALLY according to THEIR OWN DATA. - BTW: the 451VE is in actually between the HE400 and HE 500 series on that chart and is fairly new. Would the HE551VE be better suited at 600HP and only 32 lbs boost? -- YES,.. You can see that in the chart as well,.. but it starts to fall short by the time you get to the HX60. It still falls in place, but on the VERY BACK EDGE of its efficiency range. In fact, if I owned a truck with a CM2350 engine and I just simply hated a VG turbo and didn't care at all about fuel mileage because I lived in a country where I simply could not get parts for it, or i was torturing the engine and wanted better heat flow out of the engine to increase component longevity ... My second backup choice would be a HE500 series for a 600-hp cm2350. It clearly is better suited for that operating range. The only reason for considering an HX60 on that model engine would be if it were being used under high demand conditions,.. then the HX60 would be more lenient of heat flow,.. but not really efficiency gains above the 500 series. It is anyone's speculation as to why the red maker supplies the Cm2350 in foreign countries with the Hx60 on them already (like aussie land where they tend to torture their engines) but I would put a good bet on that fact alone. It is after-all inside the operating region they recommend. It could just simply have been a matter of compatibility/ease of manufacture considering it is already used on older model engines. Only they, in their engineering dept. can answer that,,. not you or I. When it comes to the CM870, 871 and its 36-39 lbs of boost,.. more pressure and more flow is required to make the same HP!!!. This is because of a lower compression ratio among other things. A larger turbo with more flow capacity is required than that of the newer engine. If I were to apply the formulas to the CM871 that I own,.. at 450HP where mine is set to,.. The HE451VE would actually be slightly more efficient in fuel mileage. -- I have already had thoughts of trading turbos with the 451VE if I have to replace mine again just to confirm this. WHAT HAS BEEN CLEARLY MISSED IS --- It is NOT about turbo size alone... An engine requiring LESS BOOST PRESSURE does not need as much umph out of the turbocharger. Period, and the more you over-size it,.. VG OR NOT!, the more you loose efficiency when all that extra umph is not needed. --- Even the 600HP engines with larger CAC units at a full 2,000 rpm are not set in their programming to demand more than 0.61 kg and that is the upper extreme. Typical for a 550 at 1800 rpm is 0.55 kg/s at best. EVERYTHING you have spewed onto my forum shouts that the team of engineers at the red engine maker GOT IT WRONG!?? -- and that you have it figured out for them? -- EVEN WHEN THE DATA YOU POSTED POINTS CLEARLY AT WHAT HEY DID WAS NOT WRONG!!!??? --- Maybe you should go offer to fix their mistake for a few million dolors eh? -- Maybe their engine can gain a bit more MPG? -- And they can beat their competitors out of the market in engine sales with this fairy dust of an idea???? -- Sorry, but I live in reality here on planet earth. -- It is clear to me now that you are looking to "sell everyone" on this fictitious world of some kind of VG turbo efficiency nightmare, possibly to sell and justify what you do to others? -- But I am not about to buy into it, not one bit. I consider it trolling at best, or indirectly phishing for information. If you really think you can put a non-vg turbo on a truck that is breaking 8mpg fully loaded to 80,000 lbs and gets 16+ mpg bobtail and beat ITS EXISTING HE551 VG TURBO with more than 580,000 miles on the turbo already,.. your more than welcome to fly out of Canada where you are at with a brand new one (and any mounting hardware needed) so that we can put it on my truck. I will have my wife drive it for a month or so and she will be able to tell right away. My fuel mileage software is sensitive to one tenth accurately all 48 states, especially now that is has 1.1 mil miles of comparison data to bank itself on from each state to each state individually. -- Otherwise,,.. you had best step on soft ground because I get tired of repeating myself on this subject over and over. The rest of what you blastered onto my forum with is just too ridiculous to comment on. -- I will kick you off here if you don't play nice,.. I know who you are and the "other" auto forum you came from. Sorry, but I don't promote a bunch of hyped synthetic data meant to spread mis-information. User's Signature: ->: What I post is just my own thoughts and Opinions! --- I AM Full Of S__T!. | |||
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