Turbo vs Supercharger
#11
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The fact is the Turbo's are pretty much trouble free,there is no huge scoop on the hatch required and Do Not need $$ mufflers, Plus that stupid belt which comes off at the wrong time is gone. Tommy did it first, and now Merc. Time will tell..but the one I was on was impressive..maybe not as much pull in comparision, but I look at it also as making components lasting longer. Jeff
#12
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The fact is the Turbo's are pretty much trouble free,there is no huge scoop on the hatch required and Do Not need $$ mufflers, Plus that stupid belt which comes off at the wrong time is gone. Tommy did it first, and now Merc. Time will tell..but the one I was on was impressive..maybe not as much pull in comparision, but I look at it also as making components lasting longer. Jeff
Then Mercury...............
Tom Earhart / Earhart Engineering has been building them longer than all of them.
However once Mercury rolled it out, everyone accepts them now as the way to go.
It's a good thing though, it pushes technology from all the builders, Blower, Turbo's, or Natural,.......everything just keeps getting better and better
Not a bad problem to have.
Jon
#13
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I think your refering to peak AE and yes, some are "higher" than superchargers. But, back pressure and high inlet temps are not "free". Also, OEM marine turbo applications use water cooled housings, which lowers there overall efficiency so one must consider this into the equation or debate.
A 4.0L twin screw, on a 540ci BB Chevrolet engine with decent parts, making 1000hp on 91-octane, 7.5psi takes less than 60hp. I would certainly not call that significant and I'm not even going to comment on your irresponsible comment. If a turbo was "free", the turbo would make 1060hp (60 more) with identical boost on an identical engine. The simple fact is that it will not.
If were discussing 30psi applications, then we can talk about significant power consumptions.
Almost all SAE studies fail to include twin-screw compressors nor later generation roots superchargers. I know of multiple studies coming out, which is leading one of the big 3 to change all there current turbo applications to positive displacement superchargers.
A 4.0L twin screw, on a 540ci BB Chevrolet engine with decent parts, making 1000hp on 91-octane, 7.5psi takes less than 60hp. I would certainly not call that significant and I'm not even going to comment on your irresponsible comment. If a turbo was "free", the turbo would make 1060hp (60 more) with identical boost on an identical engine. The simple fact is that it will not.
If were discussing 30psi applications, then we can talk about significant power consumptions.
Almost all SAE studies fail to include twin-screw compressors nor later generation roots superchargers. I know of multiple studies coming out, which is leading one of the big 3 to change all there current turbo applications to positive displacement superchargers.
If you think you can make 7.5 lbs of boost on a 1000hp engine for 60 HP, I'll call BS and leave it to you to prove me wrong. Maybe 60hp at idle. Since I don't actually have the data in front of me, I won't make it up. My guess on some side notes is closer to 240horsepower.
Based on your response and your handle, you already have your mind made up however, and we should take this offline before we murf up a perfectly good thread.
And as far as what I said about being "free", what is free is the difference in parasitic drag, you obviously lose something...
Last edited by brivander; 02-20-2012 at 06:08 PM.
#14
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Great post! I'm going to shake this thread up and give you a laymen's opinion. I sell things for a living and have to tell you sometimes a change is necessary to move product. Personally even if turbos are more efficient I love the superchargers for the sound alone. Turbos sounds like they are restricting the soul of the motor. I know they make a ton of power but at the expense of hearing it-that's bull****! I say superchargers all the way! FYI this is a drunk post with no commercial interest in this thread.
Rob
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The fact is the Turbo's are pretty much trouble free,there is no huge scoop on the hatch required and Do Not need $$ mufflers, Plus that stupid belt which comes off at the wrong time is gone. Tommy did it first, and now Merc. Time will tell..but the one I was on was impressive..maybe not as much pull in comparision, but I look at it also as making components lasting longer. Jeff
Also, it has been proven time and time again that systems with stainless tube headers are not trouble free. This may depend on the application and setup, but its by no means trouble free.
Still, I think some might miss the point, the question of which is better is like which is tastier, a strawberry or an orange? Such a question needs far more specific details in order for someone to truly say with any fact, which is better.
#16
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Jeff - I agree with your logic and facts but the comment was "Hp for nothing" which it isn't. I do agree with the scoop thing but not so much on the Whipples, the big roots type with the intercoolers are so tall and adding those big scoops just takes away from the look. Belts, again the big roots type blowers with one idler, don't know more don't come off?
As far as the first guy doing gas engine turbo's in offshore boats, didn't Merc way long ago have some turbocharged race engines before Gentry, I seem to recall that but could be wrong? If you look at the old ABPA rules (1980's) for open class there was always math for penalties for turbo engines - someone had to have them?
As far as the first guy doing gas engine turbo's in offshore boats, didn't Merc way long ago have some turbocharged race engines before Gentry, I seem to recall that but could be wrong? If you look at the old ABPA rules (1980's) for open class there was always math for penalties for turbo engines - someone had to have them?
Last edited by HabanaJoe; 02-20-2012 at 06:58 PM.
#18
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thank you all for your help .
so what im taking from this is that there is more going on with the new motor's then just the turbo to keep it reliable seem's like a lot of top end stuff . it also seem's like the doch is what's making the motor's more reliable
how much does it cost for the dohc in a motor ? is this something that most engine builder's can do and just don't because of the price or do they need special skill's to work with the dohc ?
thank's
mike
so what im taking from this is that there is more going on with the new motor's then just the turbo to keep it reliable seem's like a lot of top end stuff . it also seem's like the doch is what's making the motor's more reliable
how much does it cost for the dohc in a motor ? is this something that most engine builder's can do and just don't because of the price or do they need special skill's to work with the dohc ?
thank's
mike
#19
Daytona marine produced some turbo motors back in the late sixtes on 427 truck engines with a single carb blow through and one inter cooler. And i think they also did a 482 engine. When i am ready i will do a twin turbo setup hands down more power than anything else out there.
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Here let me make this simple -- Same boost, properly sized compressor, turbo wins, period. Since I tune powertrains for one of the big three and have seen literally thousand of data points proving this at steady state. SAE does NOT fail to look at those superchargers, in fact there are DOZENS of papers on this EXACT subject and comparisons/advantages -- some of them published, some of them not. We currently use a what you are discussing on one of our products, that used to be the "older" of the options you mentioned. If one of the OE's from Detroit is looking at it, they are retarded unless it is a specialized application so my guess if it's even true is Chryslern since GM just spent billions developing small displacement engines with turbo's And even if this is true, it's NOT because of efficiency, it's because of cost. Associated with the components and/or tuning.
If you think you can make 7.5 lbs of boost on a 1000hp engine for 60 HP, I'll call BS and leave it to you to prove me wrong. Maybe 60hp at idle. Since I don't actually have the data in front of me, I won't make it up. My guess on some side notes is closer to 240horsepower.
Based on your response and your handle, you already have your mind made up however, and we should take this offline before we murf up a perfectly good thread.
And as far as what I said about being "free", what is free is the difference in parasitic drag, you obviously lose something...
If you think you can make 7.5 lbs of boost on a 1000hp engine for 60 HP, I'll call BS and leave it to you to prove me wrong. Maybe 60hp at idle. Since I don't actually have the data in front of me, I won't make it up. My guess on some side notes is closer to 240horsepower.
Based on your response and your handle, you already have your mind made up however, and we should take this offline before we murf up a perfectly good thread.
And as far as what I said about being "free", what is free is the difference in parasitic drag, you obviously lose something...
So what your saying is that Audi is has only went away from turbo's because of cost?
Furthermore, if you are doing "calibration", you must be an engineer, and any even remotely educated engineer in any big 3 would know that 60hp at an idle is truly one of the most uneducated statements possibly ever posted on forced induction. On the same engine, at idle, the 4.0L takes less than 2hp to turn.
240hp for 1000hp? My goodness you clearly have never even looked into screw compressors, nor did you read any of the SC papers your refering too!!!!
On the identical engine, watercooled turbo vs twin screw does not automatically "win" as such a broad statement with zero facts is extremely poor in judgement. You don't even know the compression, camshaft, exhaust system, intercooler size or plumbing.
As for the OEM's, it turns out that many assumptions were made in the decision making to go with turbos on gasoline powered engines. Now that many did make the switch, with the new 2015 emission and mileage regulations, turbo's have only shown a 2% advantage on fuel mileage while costing nearly 3 times that of a positive displacment supercharger system. This is only on the production side, on the warranty side, its over twice as high to warranty the turbo applications, as some have to spin the turbo at 130,000RPM and are so close to there thermal and mechanical failure points that failures are far more common. Going even deeper, what happens to one of these small engines when the cam sensor fails? I know one 4-cylinder vehicle in particular that has a top speed of 5mph if the cam sensor fails and they can't control the cam position to get the turbo to spool soon. While it might be rare, its something that is looked at. If the vehicle is parked on just a few degree incline, it literally cannot go forward. As for torque and HP, on many of the direct injected engines, the HP is actually 1% higher, while torque at low rpm is well over 10% higher. Peak torque is a wash as many of these applications have 30+psi of back pressure.
Many have invested heavily into turbo, small engine applications and those investments were years ago, as they are working on the future packages now and as I said, many are NOT turbo.
Last edited by Whipple Charged; 02-20-2012 at 06:34 PM.