cobra marty

Many years ago ASM had that setup with the intercooler between the upper and lower plenum but it never took off. He had a few laying around back then.

tomcat

I am familiar with that piece. It was designed for a well known offshore racer for his twin turbo engines. I am not sure why it didn't catch on except maybe for the general lack of interest in turbos at the time. I wanted a bigger intercooler core and different air flow distribution into the core so it didn't work for me, but it was still a nice piece of work.

BattleCry

I had heard in Key West that a very well known engine builder has been testing some turbos for use in the marine industry.

I do like the centrifugal superchargers over the roots type blowers. I also believe that turbos and centrifugal superchargers are the wave of the future in the marine industry.
With EFI and Engine Management Systems becoming the way of life in the auto industry, its only natural that the marine industry is not far behind.

I am already looking at the idea of single turbos for my next engines in my new boat. The efficiency is there as well as adjustable HP and Torque. Exhaust is my only hang-up.

tomcat

The rumor is true, but he's not the only one. We have talked with three different engine builders about the intercooler design on both single and twin turbo systems. Intercooler size and restriction are just as important for turbos.

Turbos have been around the marine industry for a long time, but are rarely used. Gale Banks was doing it 20 years ago, and Tom Gentry spent a small fortune on his turbo engines. I think the main reason is that there are easier ways to do it in the 700 - 1000 HP range. Above that it starts to make sense but exhaust is a challenge, especially for single turbo which is harder to package. Twin is easier but previous exhaust have been cast manifolds not headers.

It is interesting that while positive displacement blowers are just now approaching the 1500 HP level, you could buy 1500 HP turbo engines for marine use from a number of builders years ago. Even the Torque V-12 was offered with twin Vortech blowers and 1500 HP three years ago. It had an enormous intercooler but the air flow pathway from blowers to intake was not designed properly for good air flow.

We are using twin Vortech blowers in our big system because the belt drive is less heat and less hassle than turbo exhaust. We can build the drive with mostly off the shelf parts, whereas a turbo exhaust system has to be a limited production header capable of supporting the weight of the turbo. To each his own, but if you're looking for 1500 HP we will have a centrifugal option for you. It will look very much like the engine at the top of this thread, but with two blowers and a much larger intercooler.

I agree that centrifugal is the way to go, but not just because of efficiency; the rotating mass is much less. Big positive displacement blowers, including PSI, Quad rotor, even Merc's 1075 dual Lysolm, all put a high demand on the belt drive system. In offshore boats where severe changes in throttle position are commonplace, those big heavy rotors do not want to accelerate and deccelerate quickly. They have lots of inertia; they want to keep going the speed they're at. I like the idea of using the beefy drives they design for those blowers to spin a pair of smaller centrifugal blowers and never have to worry because they are overkill for the smaller rotating mass.

VP

Well ----

my opinon that roots type blowers are the only ones that can provide that really cool macho look under the hatch, JUST changed !!! I see what my next homebuilt mill is going to have on it !!

Very VERY Nice !!

tomcat

Hey KevinR:

I will be in Florida Dec 10/11 (Fri/Sat). Would like to get together if possible.

Tom Robinson
(416)709-8714

Hang Time 27

Damn guys, now with all that positive feedback, he's gonna up the price!......

robyw1

Let me ask you.. Where is the cut-off point to how fast you can spin the compressor? I mean as the RPM increase there has to be a point at which the compressor becomes inefficient when compared to one with a more aggressive trim. I realize you can increase boost by spinning it faster with the change of a pulley, but at some point the compressor will start "whipping" the air heating it significantly. Do you have different compressor trim options?

tomcat

That's a very good question. Vortech rates this compressor at a max of 1100 HP. We try to stay well below Vortech's max rating. IMHO there are three things that affect this cutoff point:

- compressor efficiency as shown by the compressor map

- the maximum RPM of the impeller due to its weight and construction

- the RPM at which a serpentine drive belt begins to slip.

We have dyno tested this J-trim blower at 1000 HP @ 46,000 RPM. If you want more than that, the available trims are X, XX and Z. The X is rated at 1300, XX - 1400+ and Z we will know when Vortech gets its new blower test cell completed.