HabanaJoe

I love talking with you guys - in a manly way (LOL)!!!!

Here's my question back to you about the twin turbos - Gale Banks has it in a truck, not an offshore race/performance boat. People have put all kinds of turbo set-ups in crusier/fish style boats and they work well just like Banks' truck.

Have you ever put what you've tested/built or I call it "played with" in an offshore boat and run out in the ocean throttleing a boat for literally 40 hrs a week?

I could be wrong but even variable geometry turbos are not designed for the constant on and off the load?

I know you will fire back with those off-road ralley cars because they use it and it works well, but how dependable are those systems really??? When yo have Billion dollar car comapny sponsored factory teams I know it promotes developement but some of that is not designed to run for thousands or even hundreds of hours?

A Rally car like most vehicles when you cut the engine from being a "driver" it becomes "driven" because of the continued movement of the vehicle, the engine doesn't decellrate like a boat engine. Also, when your braking, your downshifting to keep the revs up so when you hit the gas again your at the correct rpm range to make power. A diesel boat can't really stay in the power band when the props leave the water, the govenor forces it to idle mode???

You messed with parallel turbos - how did you control/block the second turbo?

I'll tell you what we need here, is someone with lots of money to step up and say here you 3 guys built me a "real" performance diesel package and I'll underwrite the program - well I too can have a dream!!!!

mthill

Modern VG turbos are extremely durable and are meant to be constantly cycled. The newest engines use the VG to help control emissions, with a side benefit of performance. All 3 major pickup truck diesels are using VG now. It is well proven and durable. Really, VG is a potential solution, with one caution, related to your point about car vs boat.

The VG doesn't really react all that fast. The control system is seemingly well damped to avoid "overshoot" and thus overboost when moving the vanes. You really don't want to overspeed a compressor wheel! As such, it may not be ideal for a situation where the dynamics are changing the way they do in an offshore type environment. The only way to know for sure is to try it.

Generally, marine duty cycle is thought of as more steady state than on-highway. In the case of an aggressively driven offshore boat, it may very well be the opposite. Compromises will be made when the needs of one group of customers is drastically different from another. So, with VG, where you have an extremely dynamic environment, if could be excessively difficult to design a control strategy that fits multiple uses (which it must due the the financial constraints). What would you reference the vanes position to? Boost, TPS, RPM, turbo speed, etc. The interrelationships here are not trivial to establish, and it's never going to be optimized for anything but one specific set of conditions.

This is traditionally true, but there are things that can be done here that would surprise you. With a late post injection, fuel can be delivered to the cylinder at a point where it would contribute little or nothing to the torque output, but put a lot of heat into the exhaust stream, driving the turbocharger to maintain boost. It would likely be less extreme than the "launch control" or "anti-lag" used by boosted race cars where gasoline in injected such that it ignites in the exhaust manifold, pre-turbo, and very aggressively, to build boost without actually loading the engine. This system will destroy a turbo in a hurry. http://youtube.com/watch?v=gOnYA3N46kk&feature=related

Use of this type of strategy in a diesel will happen someday, though I'm not aware of anyone doing it today. Development is ongoing with electrically assisted turbos which could have a similar effect. When the exhaust gas energy falls, the electric drive takes over to keep the shaft speed, and thus boost, up. This may be a couple of years out for any real production applications, and you won't see it in marine for sometime after that.

Like I've said, we've only begun to explore the performance potential of this technology...and we have the environmental people to thank for forcing this development with air quality regulations. Most diesel innovation today is focused on reduced emissions. Re-applying it for performance reasons is a side benefit.

HabanaJoe

Your points about post injection could well be the key!!!

Again, I speak in terms of "Old School" and you guys are way above where my head is today. Your right, with electronics today the world for diesels has changed and is changing very rapidly.

So, who's got the money for us to go play with all this?

ZBODaytona

when my numbers come in, i will support you.....until then i will enjoy the reading and waiting like you for someone to step up and build some good performance diesels

29Firefox

Well there is the old school method Volvo used on the 42 series.
Turbo and a supercharger hooked up in parallel with an electric clutch on the supercharger. I think if you work the clutch control into a modern ECM it has potential.

HabanaJoe

Your right I forgot about those Volvo's!!!!!!

Did they work good?

Way back in the early 80's when the red boat above was new I had always wanted to put a roots blower on the 6.9L engine. That red boat ran a 6.9L nat. and later a 7.3L turbo. Even back then the low end boost was a problem, I remember the Volvo now and thought - a mini 6-71 with the bypass blower. I just never went through with a blower though, after realizing just how much Hp it takes to turn a blower to make boost just wasn't worth it. The diesel didn't have enough Hp to drive the blower fast enough at low rpm and then we would just so much Hp in the upper rpm range it didn't make sense.

The Volvo with the clutch made alot of sense.

29Firefox

The 6-71T had a bypass blower. The blower was always driven. The turbo was hooked up in series ahead of the blower. When the turbo boost exceeded the blower "flow" there is an internal bypass circuit. The Volvo 42 series had the turbo & blower hooked up in parallel with a little flapper inside the plenum. Which ever had more boost was applied to the intake manifold. The blower had an electric clutch like an aircon compressor. It would come in at low end and stay in till you hit the govenor or the turbo's boost exceeded the blowers then the clutch would disconnect so no top end drag.

Njawb

How about these?

29Firefox

Cat runs them on the truck base C-15 engines.

Njawb

As does Navistar/International on the PowerStroke 6.4 liter V8 that they have been fighting over with Ford.

I'm not looking so much for information on who is using them, but rather on whether they (or the similar BorgWarner e-Booster) can effectively deal with the varying load problem that concerns Joe. Seems to me that they are probably a more refined means to the same end that Joe's dual turbo application was aiming for.

There is more information available from BorgWarner: 1, 2, 3.