Re: Why are Turbos Banned?
 

well that is where the arguement begins... :D to still keep it basic, superchargers can make torque easier and turbos can make HP easier, and i am sure somebody will come back and argue that too.... they both can be tuned to produce either... they both are a compromise of sorts... i think turbos have more upsides with modern efi/computers, superchargers (gear driven style...) have the edge with carb setups.... then you have centrifugal superchargers which act like turbos driven off the crank.... :D

basically any of them will/can work and in the marine industry right now superchargers rule.... but who knows what is next? :D :evilb:

Re: Why are Turbos Banned?
 

Turbochargers work by capturing the lost energy in the form of heat and expanding gasses.So they are more efficient than a crank driven roots type or screw type blower. There is a heat drop in the exhaust temp downstream of the turbo. This energy is then transmitted through a shaft the connects the turbine wheel to a compressor wheel. The compressor wheel pressurizes the intake system for more air and fuel to be forced into the cylinders... more charge into the cylinders... more pressure and heat from the exhaust... the horsepower and pressure build exponentially until the waste gate opens and diverts the exhaust away from the turbine wheel. On some models the nozzle from the exhaust through the turbine area is large enough that it limits the amount of pressure that the compressor can make... then there is no waste gate... but there is a loss of efficiency. Turbo systems on cars have a gulp valve that allows the engine to draw air from around the turbo system to lessen the amount of turbo lag at low speeds. But... once the system is fully pressurized.... the engine has to used the fuel and air that is in the system before the engine slows down.. so there is lag coming on the throttle and lag coming off the throttle... but coming off it's not as noticable.

Re: Why are Turbos Banned?
 

Having worked at Pontiac during the development of the Turbo Trans Am, and having looked at dyno data on that engine, the atomization was NOT terrible. In fact, it was better than any other engine in production at the time. Cylinder to cylinder air fuel ratios were within 0.1 from highest to lowest even at full throttle, while the non-turbo engine would be up to 2 points highest to lowest. It was as good or better than fuel injected engines. One interesting tidbit, is the fuel did slightly erode the compressor blades over time.

Also, blow through systems do not "blow all of the fuel in the carb into the intake", any more than driving from Pikes Peak to Death Valley is going to blow all of the fuel in the carb into the intake. The boost pressure is equalized on the bowl and venturi sides. Blow through systems actually have a tendency to run lean on boost, just like your car runs leaner at low altitudes. That's why guys like Gale Banks added fuel nozzles to their blow through carbureted systems, which were run by an electric pump while on boost.

Finally, the "lag factor" is nothing to worry about. You might have 1/2 cu. ft. of volume in the carburetor box on an engine that draws 800 cu. ft. per minute. The box would only represent 0.04 seconds of air. There is more volume in the tubing and intercooler of today's injected automotive application.

Roby, stick with us! We'll get you educated on turbos! :D :D

Michael

Re: Why are Turbos Banned?
 

Well if you're using the correct AR ratio and you have your compressor wheel properly clipped/trimmed for your given application, then it will create more torque than a supercharger will at any RPM. At RPMs above 1000 the Turbocharger's torque numbers jump out on the supercharger and skyrocket from there. The Torque curve of a Turbo is very high and very flat. A supercharger's torque curve ascends to a peak as the RPM's rise then taper off when the supercharger becomes inefficient. There is only one way to make a supercharger provide more low end torque than a turbo and that is put such a small pulley on it that creates boost at idle. Even then that advantage is short lived..... Very Short Lived.

To address what Reed said I assume he is referring to a Blow-off valve (BOV) As soon as the throttle blades are slammed shut you will experience what is known as compressor surge. If a BOV is not installed then this surge is forced back through the compressor wheel and out the airbox. This will act as a huge brake for the turbo shutting it down in a hurry. If a BOV is used between the compressor and the throttlebody being actuated by manifold vacuum behind the throttle body, the BOV opens up allowing this surge to escape into the atmosphere or where ever you decide to direct it. (The sound this makes is unmistakable) Anyway the use of a good BOV will not allow the surge to slow the turbo. This is why I say when your shifting gears in a car or your on & off the throttle of a boat you will NOT experience any lag if you are using a good BOV.

The downside to a turbo if there is one is that your exhaust between the engine and turbine housing is somewhat restrictive. Because of this cam timing on the exhaust side has to be specifically designed for a turbo to achieve the best results. There can be no overlap because the added backpressure with a turbo will magnify your existing reversion problem. The cam timing on the exhaust side has to be very quick to open and close while having to be able to exhaust an increased amount of spent gasses at the same time. This is not an easy task and is usually aided by using higher ratio rockers on the exhaust side. However your good marine cams are a good start because of their design to reduce water reversion.

Roby

Re: Why are Turbos Banned?
 

i volunteer my boat for a test boat.... who's got some motors? :D :D

Re: Why are Turbos Banned?
 

I would like to see those test results of the "improved atomization" of the draw-thru system. As I understood it the thing (80 TTA) ran so hot the fuel turned to vapor when it hit the compressor housing. That's not what I mean when I say atomization.

Also could you explain the function of those 3 stages of Turbocharging those cars had? Wait let me get my inhaler incase I laugh too hard

Roby

Re: Why are Turbos Banned?
 

Just so you can see the system were talking about.

Re: Why are Turbos Banned?
 

This is a really good thread boys.....lets keep it that way. It would be great for all of performance boating to dig deeper into this. Let's not get this thread into a pissing match. :D

Re: Why are Turbos Banned?
 

It is all in good fun. I mean no ill will :D:D

Roby

Re: Why are Turbos Banned?
 

And what affect does the increased atomization have on the seventh pfizter valve?

Re: Why are Turbos Banned?
 

BigYellowCat

Only a turbo set-up could push that big tugboat of yours to 108mph. And, it made someone lose a bet. I never thought I'd see that boat at over the 100mph mark. Congradulations to you and Brad Smith, your engine builder, for making that happen.

With todays technology and engine management systems, turbochargers in a gasoline marine application is on the verge of success. There is an engine builder that has been experimenting with turbochargers.

Re: Why are Turbos Banned?
 

If you are all interested in turbo applications in marine engines, I strongly suggest you visit Hustler in a few weeks time in Miami. That's all I'll say...

Re: Why are Turbos Banned?
 

Yes, but no. The turbo's are still exhaust driven and are intercooled. The major difference is in the fuel delivery. The gas engines mix the fuel and the air together before it enters the cylinder. The mixture is then compressed and spark ignited. If you put put too much boost in the mixture will explode before it can be spark ignited which is bad. Practical boost is limited to around 7psi stock, 20-30 psi dedicated race. Now the diesels only pump air into the cylinder. This air is then compressed. Once the air is fully compressed, the fuel is added. This fuel instantly explodes creating the power. As you can see, the boost is almost limitless. Stock engines run 22psi of boost. I run around 45psi on my modified diesel. The race guys run around 100psi.

Re: Why are Turbos Banned?
 

By the looks of the box it appears you have 2 Deltagates mounted to it. Are you using them for a blow-off valves? I ask because Deltagates can only flow so much as they are designed to release exhaust. That is the reason why you had to use 2 or more. Also a good BOV such as a GReady or an HKS will open much quicker and wider than a Deltagate.

Or perhaps they just look like Deltagates from what I can see.

Re: Why are Turbos Banned?
 

I also wonder when you have the carb enclosed like that and say you are boosting up to and perhaps beyond 15-PSI, How does this affect the fuel flow to the carb? I mean the needle & seat of the carb is only good to 9-PSI. Your fuel pressure would have to be much more than the boost to keep the fuel flowing the right direction if you know what I mean.

Roby

Re: Why are Turbos Banned?
 

Does this have anything to do with Keith Eikhart building engines at Global Marine?

Re: Why are Turbos Banned?
 

yes it does...

Re: Why are Turbos Banned?
 

The regulator would be boost referenced. It's actually a pretty easy modification to make.

Re: Why are Turbos Banned?
 

I am currently running a twin turbo 572" BBC. The engine is an EFI setup with Haltech engine management. We are even controlling boost with the Haltech. I ran over 20lbs of boost the last 2 years with no failures. A #6 drive was of course necessary to handle the power. The engine is making 1500 hp. and similar torque. The gear ratio is 1:24 with a 16.5" diameter 27 pitch prop. The boat has no trouble getting on plane. The turbos have water cooled heat shields to control radiant heat. The turbo guru who designed and built most of the system is Tom Earhart.

Bill

Re: Why are Turbos Banned?
 

Now that is the right wat to do things. But... As he says #6 needed.

Roby

Re: Why are Turbos Banned?
 

Line an EFI car? Has a boost/vac line going to it? makes since now

Roby

Re: Why are Turbos Banned?
 

With all these in the works projects, i guess i have to show mine. Not really, this is just a garage show piece. I cant wait to see what happens in the next year with EFI Turbo setups.

Re: Why are Turbos Banned?
 

Plenty of horsepower and monster turbo's :D

Re: Why are Turbos Banned?
 

did someone say big turbo?

Re: Why are Turbos Banned?
 

:eek: :eek: :eek: :eek: Delo needs a set...................... and an aircraft carrier. :D

Re: Why are Turbos Banned?
 

Bob Kaiser in his systems offshore team had some turbos on his boat. The technology was not there but he had the right ideas. Small blocks with turbos. The boat was introduced in 1989 and went on working the bugs out through out the season. The technology was just not there.
Hunter

Re: Why are Turbos Banned?
 

I don't believe you can actually call them small blocks as they were merely a 454 de stroked to a 348.

Gentry did the same thing to get around the rules.

Kaiser's engines were the product of Mike D'Anniballe's work in his early days.

Re: Why are Turbos Banned?
 

The systems turbo boat "thank Mr CIG for the pic" :D

Re: Why are Turbos Banned?
 

490 cu in @15 lbs boost = 1540hp in racing ski boat. Combination is very durable, EGT's stabilize in the mid 1400's an hour at a time for each race. This is a common combination made by Gary Teague @ GT Performance. He also makes a lower profile version for pump gas at roughly 1100hp. 909-982-8391



http://img.photobucket.com/albums/v2.../1540hp_tt.jpg

Re: Why are Turbos Banned?
 

A SKI BOAT??? :eek: :eek: :eek: :eek:

Re: Why are Turbos Banned?
 

Big Inch? Reliability? High Horsepower? All at the same time? This CAN'T be true? This is boating and engine builders have said for years that high horsepower and reliability DO NOT go hand in hand. :cool: