Compound Charged VH45?

[Guishnu]

I guess this would make it a VH45DES-TTDoes anybody have an information or opinions on this?

Running a VH45 with a pair of larger turbo's for power and a super charger for instant response. The BeeR S15 runs a very similar setup but with just a single turbo. The turbo blows through the super charger and gives 1 bar of boost from nothing.

I know the VH45 has a bucket load of torque anyways, but do you think this would work?

Opinions?
Modified by Guishnu at 7:56 AM 2/26/2007

[Mettler]

Er, what ? You mean twincharging the engine with a supercharger and a turbocharger ?

[Guishnu]

Yes.Two turbo's one super charger

[Q45tech]

The most effcient method would be to use a separate small 25-30 HP snowmobile engine to drive a supercharger chill the output and skip the back pressure from turbos and the crank robbing power of a supercharger.

[Guishnu]

Noval idea So you would run the snow mobile motor to power the super charger?

Interesting...

[slownslurious]

novel idea especially when you consider that the supercharger would consume less than 30 hp itself... and then you get into the fun ideas of packaging the extra motor, the weight of the extra motor, and you start to extend the bumper to make room for it and the package throws off your weight distribution and you realize you have to supply fuel and cool the 2nd engine as well which is competing for radiator space with your VH you realize that damn.. maybe just running it off the crank wasn't such a bad idea after all lol

not to poo poo the twincharger idea, but its been done with mixed results, its not like the golden bullet and it has plenty of flaws. The main flaw is that with twin turbochargers and a supercharger ( you didn't specify but I'll assume you intended a roots blower since a centrifugal will often model the respone of a large turbocharger) you are going to have 1) great increase in weight, 2) great increase in complexity of piping and oil/water lines (also adding more weight and making trouble shooting difficult, 3) an engine bay that is really hard to work on, and 4) not much better response because the supercharger will be drawing air through the not yet spooled turbochargers (assuming you go for large ones, otherwise why do we need the supercharger) and not much better boost on the top because the turbochargers will be jamming air through the rotors of the supercharger (which the air will be flowing faster than, which means friction, which means heat and inefficiency).

At the very least simplify the idea to a single large turbocharger and a roots style blower with an integrated water to air intercooler. it would make the engine a lot simpler in design and packaging.

In general though, with a properly sized ball bearing center section turbocharger you should be able to acheive acceptable response without sacrificing boost at the higher end of the power band.

You didn't specify what you are building the motor for but in all likely hood the only application needing such a large frame turbocharger on a VH would be a drag application, in which case nitrous oxide would be a much more efficient (in cost and in weight/performance) means to spool up the turbocharger.

[mtcookson]

If you're looking for instant boost with good efficiency, just go straight to a screws supercharger. They give instant boost like a roots charger but are much, much more efficient. Almost as efficient as a turbocharger setup. Plus it would probably be the same price if not much cheaper than doing twin turbo w/ supercharger setup.

[slownslurious]

where did you get that info from? I've never heard anyone say that a screw type supercharger is any more efficient than a rotor style supercharger... in fact my supercharging books say they are about the same for designs with similar tolerances.

screw pumps are generally used for moving large amounts of things at low rpms, there aren't a whole lot of people using screw superchargers anymore. lysholm screw type superchargers are around but its highly evolved from a basic screw and is pretty hard to find.

[mtcookson]

Yeah I was talking about the Lysholm and Whipple s/c's. They are quite a bit more efficient than the roots type. I've seen quite a few Ford Cobra guys using them. They can definitely make some awesome power... but I'm still a turbo guy.

[slownslurious]

yeah a whipple isn't any more efficient than a modern eaton, they have the rotor tolerances down so close anymore that they are surprisngly efficient at lower power levels. The whipples they sell for the cobras are designed for significantly higher power levels than the eaton M112 will support though, so you can't confuse ultimate power output with efficiency. Those big blowers push more air through the motor sure, but they also consume their porportional share of crank horsepower as well.

Im planning running an eaton to get as much torque as I can.

[mtcookson]

Which efficiency are you speaking of? As far as adiabatic efficiency (heat efficiency) goes, a screws is way more efficient than a roots. They don't produce as much heat for the particular boost level you're running compared to a roots. They've definitely got the adiabatic efficiency of the roots blowers up but they still aren't on level with the other forms of boost (screws and centrifugal).

A roots s/c is basically just a blower, not even a compression. It just blows enough air into the intake manifold that the air compresses in the intake manifold itself. You get boost this way, but it is much hotter than if you were to compress the air in the unit itself like the screws.

Power consumption wise, I'd agree that they likely consume very similar amounts of power to operate.

Don't take any of that the wrong way though... even though the centrifugal supercharger is more efficient than a roots, I would take a roots over a c-s/c any day... any day at all. I would still take a turbo above the rest, but that's not to say I wouldn't venture into the roots and screws setups sometime.

Modified by mtcookson at 8:05 PM 3/7/2007
Modified by mtcookson at 8:07 PM 3/7/2007

[Mettler]

Has anyone thought about a parallel twinturbo setup per bank, with a big turbo and a little turbo both operating off the same exhaust manifold on each side, both internally wastegated ?

The exhaust outputs would merge, as would the intake side.

The intent is obviously to allow the small turbo to spool just off idle, and the big turbo to supply the major kick in the pants. Of course, the boost periods would need to be tuned to overlap significantly.



Any reasons why this would not work ?

[slownslurious]

yeah but with modern turbos the plumbing nightmare and headaches aren't really worth it... I mean its been done before (ala 959) its just pretty complicated.

[doctorchee]

my personally point of view for the thread is the more simple the better.

I just feel, complicated set up needs lots of testing equipment etc. there may be many technical, tunning, effieciency issue problem whcih can only be diagnosed with high tech euqipment. At the end of it, chances is, the idea gives more problem rather than improving things.

perhaps getting a big turbo with ball bearing helps to cut down lag, a nos to spool it at low rpm or a Titinum turbo which can spool fast and hard may be a better idea? at least all this are sure improvement tested and proven.

just like to share my view.

All new or uncommon ideas always comes from someone who is brave enough to try and does all the hard dirty work.

At the end of it, isn't modifying car is our hobby? no problem can be boring at times hahahaah

good luck......

[mtcookson]

Has anyone thought about a parallel twinturbo setup per bank, with a big turbo and a little turbo both operating off the same exhaust manifold on each side, both internally wastegated ?

The exhaust outputs would merge, as would the intake side.

The intent is obviously to allow the small turbo to spool just off idle, and the big turbo to supply the major kick in the pants. Of course, the boost periods would need to be tuned to overlap significantly.

http://i162.photobucket.com/al...t.jpg

Any reasons why this would not work ?

With current turbo technology like ball bearing center sections and much better wheel designs, I think a sequential setup is really not needed anymore. I know there are still quite a few big power diesel engines that use a setup similar to that but the way they run is like so:

Manifolds -> small turbo exhaust inlet -> small turbo exhaust outlet -> large turbo exhaust inlet

A better way would be something similar to yours but with a valve that would completely close off exhaust flow to the smaller turbo for the best output and efficiency you can get. Though, like I mentioned above, its really just not necessary with current technology. Even better, when variable turbos start to finally become more common place it would totally remove any need for a sequential setup like that and they could even take the place of the positive displacement s/c's in producing more low end power.

Honeywell (Garrett) is currently working on a variable turbine AND compressor... that will most definitely outperform the superchargers all together. Sure s/c's will still be around due to great reliability (roots) and just due to peoples' personal preferences, but this new turbo will definitely make for some very crazy cars... eventually.

[maxnix]

Wouldn't variable vane work better?

Seems like the best engine to study is the similar closed deck designed Porsche V8 twin turbo. They have done most of the engineering for us.

[mtcookson]

I think variable area would probably be the best... at the very least more reliable.