With some of the experimentation with turbos that's going on, and the development of kits for the Gen II Lightning, I'm wondering if a Twincharging system would work or if anyone is trying this? With the Turbo feeding into the Roots blower.

There were a couple of guys here some years ago that were working on systems that incorporated a Novi 2000 Centrifugal blower with the stock Eaton. I'm not sure if they ever got them right; since, the projects and their owners just disappeared from the site. Has anyone considered going this route with your Turbo installation. It seems like it would save some money on intake parts. I don't know if there is more power to be had that way or not though. This is a discussion question. I don't intend doing it myself. Just curious.


Any comments?

~Roger

 

talk about a headache!~

If you want to save money, sell your stock parts to offset the new parts cost.

Do what Sal did with his turbo setup and remove the rotors and pulley off the eaton case and use that as an intake.

 

I think it's a solid idea. Basically the Eaton will just make the turbo see an engine with a higher volumetric efficiency.

The only place I have seen this tested was Turbo magazine. They tested a 3.0 V6 Toyota motor in a MR2 both with turbo only and turbo with a roots blower. The results were that dual-charged there was minimum 40 rwhp gain across the board (like what you'd expect with a bigger VE or larger engine).

A the same peak psi (22-23psi) the turbo alone made 455 rwhp and the turbo/roots made 524 rwhp. The turbo alone had to be boosted to 28.5psi to match the turbo/roots combo power.

Of course this wasn't our engines and I'm sure the turbo choice may make a difference. However... it does show there is merit in the compound boost idea .

 

Odin's Wrath, I dont know what this combo would do on our trucks but this application is used and mass produced. Ive be turning wrenches for the Army for 10 years. This motor/turbo/supercharger combo is used in a couple different vehicles (Army). The first one that came out tuned for longevity makes a modest 800Hp and 1200ftlbs of torque. They last for a long time and only need normal scheduled maintenance. The turbo is feed directley into a roots type blower that is gear driven. The intercooler setup is almost identical to ours. This is an 8cylinder 2 cylcle diesel.

 

Diesel applications are the root of the idea for me. I've seen those engines in Heavy Hauling Transportation apps. before. I know it works. I don't know why it hasn't came up here before. I find it an interesting direction to take a Lightning. I think VW is coming out with a similar set-up for its 1.4 L Golf GT. Actually, I think they already have it in Europe. It's supposed to be more powerful and more fuel efficient.

 

And VW or Audi or SOMEONE (I forgot) also now makes and sells
a Turbo / Supercharge Vehicle. It's been available for quite a while now,
I read a great article on it quite some time ago.

The Supercharger takes off from idle and sends the Boost into a conversion
"THINGY" then the Turbo comes in at a certain RPM/MPH with the Pre-Boost of the Supercharger and it takes over already Boosted up

 

my first impression would be that the rotors in the roots would be restrictive to the air flow from the turbo, and thus made very little difference. I am no expert.

Wouldn't it be alot easier to just put on a larger turbo are larger blower?

 

Yep it was VW I thought so, they did it so they could make the displacement smaller (hence better gas mpg).

http://www.greencarcongress.com/2005..._vws_new_.html


Some of the highlights





Inside VW’s New “Twincharger” TSI Engine
31 August 2005

The TSI Twincharging systems
VW’s goal for its new dual-charged (“Twincharger” in VW marketing-parlance) engine (earlier post) was to combine the low-end power boost provided by a mechanically-driven compressor (supercharging) with the higher-end increase provided by an exhaust turbocharger (turbocharging) to enable the downsizing of the engine for a given application while maintaining the driving experience for consumers.

Put another way, downsizing delivers comparable (or better) performance with lowered fuel consumption and emissions.


To support the twincharging concept, VW engineers had to deliver a new, highly-resilient gray cast-iron cylinder crankcase to withstand the higher pressures, a coolant pump with an integrated magnetic clutch and supercharging technology.

VW also modified the injection system, introducing its first multiple-hole, high-pressure injection valve with six fuel outlet elements.

The injector, like that in the naturally-aspirated (non-charged) FSI engines, is arranged on the intake side between the intake port and cylinder head seal level.

To support the wider variability in the quantity of fuel needed across the range of operation (from idling speed to the 90-kW peak power output) to optimize the twincharging, VW increased the maximum injection pressure to 150 bar.

For the compressor, Volkswagen engineers chose a Roots-type supercharger (also known as a “blower”). Unlike some other types of supercharger, a Roots supercharger doesn’t actually compress air within the device. With two counter-rotating lobes, it moves a fixed volume of air per rotation (“fixed displacement”). Compression occurs in the intake manifold.

Roots superchargers can deliver a large amount of boost even at low engine speed. The main disadvantage is that they create a lot of heat.


Air flow through the VW Twincharged TSI.
The compressor and the turbocharger are connected in series. A control valve ensures that the fresh air required for a given operating state can get through either to the exhaust turbocharger or the compressor.

The control valve is open when the exhaust turbocharger is operating alone. In this case, the air follows the normal path as in conventional turbo engines, via the front charge-air cooler and the throttle valve into the induction manifold.

The compressor is operated by a magnetic clutch integrated in a module inside the water pump. Under turbocharging conditions, the clutch disengages the compressor.

The maximum boost pressure of the Twincharger is approximately 2.5 bar at 1,500 rpm, with the exhaust turbocharger and the mechanical supercharger being operated with about the same pressure ratio (approx. 1.53). The compressor alone delivers a boost pressure of 1.8 bar even just above idling speed.

A conventional exhaust turbocharged engine without compressor assistance would achieve only a pressure ratio of about 1.3 bar.

The more rapid response of the turbocharger enables the compressor to be depressurized earlier by continuous opening of the bypass valve. Compressor operation is restricted to a narrow engine map area with predominantly low pressure ratios and, therefore, low power consumption.

In practice, this means the compressor is only required for generating the required boost pressure in the engine speed range up to 2,400 rpm. The exhaust turbocharger is designed for optimum efficiency in the upper power range and provides adequate boost pressure even in the medium speed range.

For acceleration, an automatic boost pressure control decides if the compressor needs to be switched on to deliver the tractive power required, or if the turbocharger alone can handle the situation.

The compressor is switched on again if the speed drops to the lower range and then power is demanded again. The turbocharger alone delivers adequate boost pressure above 3,500 rpm.

 

Did someone say Eaton and turbo? There is a twincharged Saturn Ion: HERE Pretty neat idea.

 

I remembered I read where a production car was using compound boost. Forgot it was the VW though, thanks for the info Rob. The VW is a little different than what the Turbo magazine tested in that VW has the roots feeding the turbo rather than the turbo feeding the roots... like what a Lightning (or that Saturn) would do.

I must admit I've had a twincharged system planned out for my L for quit a while. I'm just slow getting started on it, and was going to wait and see how it performed before I posted about it . Guess if it works awful at least I'll learn something from it right...

 

feeding a turbo into a supercharger is going to gain nothing.. a turbo will move more air than a supercharger ever will. Feeding a turbo into the supercharger will only let less air in.

 

You know this because you've tried it? The only testing I have seen of the idea (see my first post) it worked great. If you have other data please share, seriously... I'm not trying to be a smart a$$. I'd absolutely love to read more about other people that have tried it. If it's just random theories though about why it won't work, can't honestly say I care to read about that (no offense).

My original turbo design was to run through my Eaton case anyway so I thought 'hey why not try compound boost'. It'll be easy enough to pull the rotors if it doesn't work. Lots to gain little to loose in my mind.

 

Yah, you may be right. I don't want to argue with anyone that it will work, because I don't know if it will or not. I just think that it might work and it's worth a shot to try it.

Guess the restriction theory is that the roots doesn't restrict boost, it just compounds it as it passes through. In the article they have boost gauges before and after the roots to see which power adder is contributing the boost. For example:
4.3 total psi--1.3psi from turbo--3.0 from roots
12.3 total psi--9.0psi from turbo--3.3 from roots
22.7 total psi--19psi from turbo--3.7 from roots

 

A turbo will flow more air at a faster rate than a supercharger will, thats a proven fact. 8lbs of boost on a turbo is like 16lbs on a supercharger(these numbers are just to use as an example) a turbo is more effeciant than a s/c. Why try and shove a greater volume of air and at a faster rate and slow it down by trying to shove it through a supercharger that only can flow air so fast... I can see how the turbo might make the s/c spin faster but then you have to look at the heat from the turbo then the heat that will be present from spinning the blower faster. You also have to look at the fact that if your using a turbo to spin the blower you might be over spinning the blower and just cause trouble in the long run.

You might be able to use a s/c like a vortech to spin the turbo so you dont have any turbo lag but then again you have to look at the fact that the s/c can only push so much air. SO at higher rpms you may not be able to get enough air through the s/c and can starve the turbo...

I have not done this first hand but i hang out at the shop that did the same setup on a mr2 with the v6 engine lost horsepower The v6 was out of a toyota camary...They were in a magazine as well. They lost hp/boost with the turbo feeding into a supercharger. Took the s/c off and it ran better and got better numbers. I cant remeber the numbers since its been a long time since they did it.

Only way i see using a turbo and feeding it into a supercharger and getting a gain is if the turbo is realy small.

Just do it the right way, get a big turbo and ditch the blower. I dont see anything wrong with using the case of the supercharger as a intake for the turbo just take the rotors out.

 

The diesel application you saw this on would be a 2-stroke diesel engine. The supercharger on this application is only used to scavenge the exhaust left over in the cylinder.

Zach