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Turbo vs blower
Why dont we see more turbos in hp engines in powerboating would think the lag would not be a issue with motors always loaded
you would think they would be easer on parts vs blowers |
Turbos work by using the exhaust from the motor, so I would guess the water in the exhaust has something to do with it
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that makes sense da.
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The constant on/off isn't really well suited for turbos. Plus, to be Coast Guard approved, the application has to be completely water-cooled. To do so interferes with turbo efficiency. If the turbine housing is cooled, that draws heat away from the unit. The turbine uses that heat to drive the compressor.
Mercury did quite a bit with turbos in the late 80's and early 90's. The APBA was less than friendly and accommodating on the topic. Tom Gentry did well with his turbo engines but nobody was really interested in the concept. As far as reliability, they've been putting superchargers on production automobiles for some time now- the reliability issue is pretty much licked. turbos are substantially more complex that superchargers. The plumbing alone can be very complex- with pressurized oil for the bearings, wastegates, cooling, etc. Blowers are cheap, easy and reliable. And, a way more linear power curve in the process. |
Originally Posted by bblythe
(Post 2347324)
Why dont we see more turbos in hp engines in powerboating would think the lag would not be a issue with motors always loaded
you would think they would be easer on parts vs blowers |
Originally Posted by Bigyellowcat
(Post 2347350)
the only problem is engine builders not knowing how a turbo works.
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While a supercharger's boost curve is linear, the power curve is not.
When a turbo spools up, it makes max boost then. At whatever RPM range, and holds that to red line. A supercharger has a linear increase in boost (centrifugal), or volume (roots/screw), that maxes at max rpm. So while WOT will be similar in power, the power under the curve of a turbo will be much higher. There are many downsides to properly applying turbos in boats. Look at drag racing, turbos are increasing in numbers almost every month. Also, the parasitic draw of a supercharger is huge. I haven't been able to find it again, but there was a test done with a turbo/supercharged ford engine. They ran the engine N/A, and put a 20 lb boost regulator on the output of the supercharger and turbo. They found that the turbo took about 20hp to run, and the supercharger around 300. These were moving the same amount of air at the same pressue, with the engine running the same N/A induction. So, you get an extra 300 hp that the engine is making already.. so in theory if you make the same Hp turbo vs blower, there is far less strain on the engine. |
Originally Posted by Joe92GT
(Post 2347376)
While a supercharger's boost curve is linear, the power curve is not.
When a turbo spools up, it makes max boost then. At whatever RPM range, and holds that to red line. A supercharger has a linear increase in boost (centrifugal), or volume (roots/screw), that maxes at max rpm. So while WOT will be similar in power, the power under the curve of a turbo will be much higher. A roots blower will make max boost depending on load and not necessarily based on rpm. If youre cruising at 2000rpms and mash the throttle, it will go to max boost almost instantly and stay there all the way to max rpm. |
Turbos run best on cold and thin air. The higher the alitiude the better the performance. To be effective they must be installed before water is introduced into the exhaust system. Turbos also work best on quick-high rev engines. Wastegates would be another issue.
Performance boats usually run two exhaust pipes. Therefore todays typical exhaust configuration in a twin engine boat would require four turbos. The Turbo Inlet Temperature (TIT) could get as high as 1850 degrees if leaned to much. Turbos require a cool down before shutting down. No cool down results to a melt down of the turbo's bearings. A turbo on a boat would require constant monitoring of temperatures and adjustment of richness to keep the temperature in line. This operation can be achieved with computers as in todays cars or be done manually ( a lot of monitoring). Prochargers are the way to go. Wesco (Jenison, Mi) is building a line of performace boat motors with single and dual prochargers. These units are equipped with chill boxes to conidtion and densify the air before induction. Some cool stuff. A set of these will be running in the Fort Myers area around the beginning of next year. No blower belts, chillers or big blowers to haul around. A couple hundred pounds off each engine. That is large. |
Originally Posted by The Menace
(Post 2347405)
Turbos require a cool down before shutting down. No cool down results to a melt down of the turbo's bearings. .
how often have you ran you boat hard and then instantly shut the engine off, never unless you were broke, you always have a cool down period to get to the dock, trailer, party spot, ect. |
Originally Posted by Chris Sunkin
(Post 2347370)
With many performance boaters and racers operating with huge, if not unlimited budgets and with the quality of engine builders the likes of Sterling, etc., that's not likely.
you find someone to let us build them a set of turbo engines and we will give them more power then any marine engine builder offers, and give them a 200 hour warranty with it. |
How About The Turbo Engines For Tommy At Chief. I Know There Running In A Apache Setup. Also Seen A 43 Nortech Cat With Them. Owner Says There Working Well
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Originally Posted by Bigyellowcat
(Post 2347424)
that furthers my example, they are giving the money to people that do not know what a turbo does.
you find someone to let us build them a set of turbo engines and we will give them more power then any marine engine builder offers, and give them a 200 hour warranty with it. Turbocharging is what you might call a mature science. The ancillary pieces, from ceramics, to coatings to exotic materials and all the associated tweaks and techniques have been around for a LONG time. |
Tommy Is On It!
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Originally Posted by RICKY PEREZ
(Post 2347488)
How About The Turbo Engines For Tommy At Chief. I Know There Running In A Apache Setup. Also Seen A 43 Nortech Cat With Them. Owner Says There Working Well
Another thread: http://www.offshoreonly.com/forums/s...t=chief+turbos |
Originally Posted by Chris Sunkin
(Post 2347493)
So what you're saying is that in spite of the millions of dollars and tens of thousands of engineering and development hours spent by Brunswick's Mercury HP division,mega-millionaire Tom Gentry, Gale Banks and not to mention the scores of others just since WW II, you know something they weren't able to recognize?
. yeah that is pretty much what I'm saying. I have ran my turbo engines for 5 years at 1800 hp and they have the same cranks, rods, pistons, valves, blocks, ect. times 2. that they were built with. only did normal maintenance oil changes and valve springs, lifters, gaskets ect. just to give you an example, I build custom speakers, and speakers have been around for over a hundred years, and there are lots of companies like sony and jvc ect that have billions of dollars that cannot even come close to what I have done with speakers. it is pretty easy to look at a banks kit or gentry kit and see what they did wrong. just because they had money does not mean they knew what they were doing. We are willing to build them and stand behind them like I said. |
Originally Posted by Chris Sunkin
(Post 2347493)
Turbocharging is what you might call a mature science. The ancillary pieces, from ceramics, to coatings to exotic materials and all the associated tweaks and techniques have been around for a LONG time.
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Turbo's kick A$$.
Worked for Schwitzer for 10 some years in advance turbo design. Perty much fathered the first successful turbine end variable geometry turbo. Also designed the safest and most sofisticated stationary test and burst test equipment. |
Originally Posted by DonziJapan
(Post 2347544)
Fact a blower's boost is proportional to the input RPM. Now what your describing is an illusion. The blower doesn't achieve max boost at the lower RPM either the guage has topped out or there is a relief valve that has opened at a preset level of boost and is dumping the excess. In fact the blower is putting out more boost than your instruments are telling ya.:evilb:
Rev a roots blower engine slowly up to 5000rpms in neutral and see how much boost you make. Very little, if any. Now put it in gear and mash the throttle. You'll be very near max boost by 2000rpms and stay there all the way to max rpm. |
Turbos are superior to any other forced induction engine period.
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Originally Posted by Bigyellowcat
(Post 2347593)
yeah that is pretty much what I'm saying.
it is pretty easy to look at a banks kit or gentry kit and see what they did wrong. just because they had money does not mean they knew what they were doing. We are willing to build them and stand behind them like I said. |
I had a turbo charged engine in a boat for the last 30 year except for the last 3. My turbo motors with waste gates would go to max boost (I had set for 10lbs) just off idle. The neat thing about turbos with wastegates is I could dial in the amount of boost I wanted, from min. of 5 to max of 15, just by turning a dial on my dash.
My procharged motor will not go to max boost until max rpm. As to why Mercury not doing it, I think the cost and complexity, and peoples fear of them is why. |
Originally Posted by Chris Sunkin
(Post 2347729)
What is it that so many have missed in turbo application that you were able to discover & apply to your setups.
I have 2 friends that bought similar boats back in the early 80's one went the Gale Banks 800HP setup, Other went the roots blower setup. After a few years and a few motors the roots blower guy went Turbos. |
Originally Posted by KNOT-RIGHT
(Post 2347722)
Turbos are superior to any other forced induction engine period.
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I've always understood that turbochargers are much better for the engine than superchargers.
How much horsepower can you get out of a reliable turbocharged small block marine engine? |
Originally Posted by Griff
(Post 2347696)
FACT!!!!!!!!!!!You have to have a load on the engine to make any significant boost on a roots blower.
Rev a roots blower engine slowly up to 5000rpms in neutral and see how much boost you make. Very little, if any. Now put it in gear and mash the throttle. You'll be very near max boost by 2000rpms and stay there all the way to max rpm. |
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Originally Posted by TexomaPowerboater
(Post 2347831)
How much horsepower can you get out of a reliable turbocharged small block marine engine?
23' headed conventional engine around 750 hp reliable SB2 headed conventional engine around 900 hp reliable LS1 style engine around 1000 hp reliable which one do you want? |
Originally Posted by turbo2256b
(Post 2347667)
Turbo's kick A$$.
Worked for Schwitzer for 10 some years in advance turbo design. Perty much fathered the first successful turbine end variable geometry turbo. Also designed the safest and most sofisticated stationary test and burst test equipment. |
Didn't Mercury have quad turbo's on the kilo cig a few years ago? Chief is using turbo's, BYC has some killer pieces as well.
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http://www.youtube.com/watch?v=p4mYHGLAXY0
Nice exhuast by the way. How have they been working? Did you get the pressure pop-off's on your sea strainer? |
or if you like roots blowers, hear is a regular old 500cid 871 blower motor... from a tractor puller, on alky!!! :D :D :D
http://www.youtube.com/watch?v=q621p...eature=related |
Some times with turbos simple is the best....
Deisel turbos in big boats are ussually shaft driven arn't they? |
Originally Posted by Chris Sunkin
(Post 2347370)
With many performance boaters and racers operating with huge, if not unlimited budgets and with the quality of engine builders the likes of Sterling, etc., that's not likely.
Michael |
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you were asking about small block turbo engines, this is brads 355 cuin small block turbo charged. it made 750 hp on pump gas at a low boost.
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Originally Posted by DonziJapan
(Post 2347934)
The same thing happens with turbos on an unloaded engine it doesn't register boost on the gauge. Load does not "make" boost. An unloaded engine is more volumetrically efficient than a loaded one. Which means the fuel and air flow through easier. The boost is the same between an loaded or unloaded engine its the difference in resistance that causes the difference in your boost pressure gauge readings. To further simplify what you're looking at consider this. A roots blower is a form of compressor. Take your garden variety shop compressor. It has a fixed output same rpm same piston. Run it with the valve open the pressure will never build. But close the valve and pressure will build. Either situation the output of the compressor is the same just the load has changed so the gage reading changes. Your "boost" gauge is nothing but a pressure gauge reading the air pressure in your intake manifold. The intake manifold is like the tank on your shop compressor and loading the engine equates to closing the valve on the tank. Hence the rise in pressure in the intake manifold. Now this is the fact the output of the roots blower is linear in regard to the engine rpms. The lobes on a roots blower displace a fixed amount of air each time they go around. The output is determined by how many times the lobes go around in a minute. Some blowers are driven at different ratios than the engine but still the output graph will be in a straight line just at a different angle. Again we're back to the illusion of boost on your pressure gauge.he blower doesn't achieve max boost at the lower RPM either the gauge has topped out or there is a relief valve that has opened at a preset level of boost and is dumping the excess. In fact the blower is putting out more boost as the rpms rise than your boost gauge is telling you. :evilb:
You can change the boost pressures on an engine without changing anything on the blower. Increase the flow of the heads and add more free flowing exhaust and boost pressure will drop. Actual volume being pushed through the blower will remain the same. The boost gauge reads correctly and is not topped out. I agree, its measuring the boost pressure in the intake but its also measuring the pounds of pressure forcing the intake charge into into the cylinders. There is no relief valve or waste gate on the supercharger or intake. |
In answer to the original question, turbos are easier on parts than blowers. I have been running twin turbo engine configurations for over 10 years and consistently get more time between rebuilds than my blower loving friends.
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Originally Posted by Bigyellowcat
(Post 2347593)
I have ran my turbo engines for 5 years at 1800 hp and they have the same cranks, rods, pistons, valves, blocks, ect. times 2. that they were built with. only did normal maintenance oil changes and valve springs, lifters, gaskets ect.
We are willing to build them and stand behind them like I said. Nice work ! Jon |
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Pretty low RPM, that is one reason my engines have lasted. we usually only turn them in the 4000 rpm range but I have over 1100 hp at 4k. I run 110 octane fuel. I will admit that the 1800 hp was at around 20 lbs of boost on a 9.5-1 engine.
I tell people that my engines made 2000 hp because we ran the texoma run and the shootout at 25 lbs of boost but we never dynoed them with that high of boost. kind of scarry when all that tubing we made to dyno them kept shooting off the engine. |
Good thread....shows how much mis-conception/ mis-understanding there is about what effects hp, boost, rpms, etc. have on engines of any type. Also, doesn't Merc Racing electronically bleed boost of the 700SCi package, for torque management?
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Originally Posted by Bigyellowcat
(Post 2348466)
Pretty low RPM, that is one reason my engines have lasted. we usually only turn them in the 4000 rpm range but I have over 1100 hp at 4k. I run 110 octane fuel. I will admit that the 1800 hp was at around 20 lbs of boost on a 9.5-1 engine.
I tell people that my engines made 2000 hp because we ran the texoma run and the shootout at 25 lbs of boost but we never dynoed them with that high of boost. kind of scarry when all that tubing we made to dyno them kept shooting off the engine. What speeds did you get at the Texoma run with 25lbs of boost? Still running the Apache Cat? Thanks Jon |
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