Anyways, lars1, back on topic. Don't let that guy distract you trying to sell low-quality stuff for Rotrex, the company he represents.

Back to the Eaton M112. It would work well as a first sequential stage (twincharger) if you installed a bypass valve or pulley clutch. The Famous "Green Wagon" used a similar setup but he overcomplicated it and the project ultimately failed before ever racing competitively. Exactly what failed, is unknown.

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Polarismrk: It is okay to have another opinion, BUT Show us some proof, that supports your typing!

FI: I like the idea of what he did with his "Green wagon 617", but I have a question.

Why did he choose to pull the air through the turbo before the SC? It seems to me that the purpose of a sequential SC/turbo setup was to make the SC do the work BEFORE and below the boost treshold of the turbo.

I think It would work better if he routed it so that both the SC and turbo pulled ambient air from a separate airfilter each. -And moved the IC to just before the engine intake. Then, (IN MY MIND), it seems that the Scharger would work until the turbo builds more boost and one-way valve opens for using turbocharger-pressurized air.

It might give you a flucturation in airflow and torque just at the time when turbo takes over from SC, but it should not be too bad, i think.

You would also need a discharge valve to let the turboair escape after you let the throttle off to avoid stalling when the valve closes. Pusssh like a gasser.
I wish I was good at computer and could make a schematic drawing, but i hope u understand what i am thinking about. (-Like his, but move IC to manifold, add a blowoff valve between turbo and oneway-valve, and let both suck ambient)

And you could top it all off, with SC air-recirculation under light load and a clutch(Aircond on/off) disconnecting it from the crank at say 3000rpms and above to reduce parasite load at higher rpms when the turbo is doing the job anyway. Just some thoughts

There wouldn't be any problem having the supercharger after the turbo, you would need a bypass to let the turbo unrestrictively blow around the SC. Thats what the valve was for but why he chose to use a long tube above the intercooler is a mystery. I would have made it a short tube between the SC's inlet and outlet tubes to allow for a bigger intercooler and more efficient plumbing.

Non-electronic control would never be a silky smooth transition but it can be minimized with tuning.

Thats if you have a clutched SC. Most Roots makers claim about 1/3hp to drive it using a bypass valve.

The biggest problem with a positive displacement SC is too much torque at low RPMs. Finns using VNT turbos (attachment) say they have to limit low-rpm torque (boost) to prevent damage.

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Photos will be coming as soon as i get the charger on my w126. Like I said before "forced induction" started demanding proof, this is a project i am going to do this summer. I will gladly keep you posted. BTW The company I work for also sells Eaton, Kenne Bell, Vortech, Whipple, Garrett Products so I am not "Advertising" or trying to sell anything to anyone. They are all great products, and instead of product bashing i will give you the reason why i have chose to put the charger on that i am. It is much more compact than the others. I know "forcedinduction" will have some smart comment about this but there is no false information here. I think an eaton would also work wonderfully for you. Do you have any Designs yet for a way to divert boost between turbo and supercharger? Where would you be mounting the Eaton unit?

__________________
1987 300D 180k
1985 300SD 330k Helga
1992 300D Lola 269k- Sold
1986 325 coupe Bessie >300k Original engine(ODO Broke) sold
2006 2500HD Druamax Linda- Tows boat and looks pretty in garage thats about it

So is a VNT since it occupies the same space as the existing turbo, plus it will perform better on the low end (where you said you want power) and more efficiently using waste exhaust energy instead of raw crankshaft power.

I will be using a supercharger not a VNT. I am doing this for fun not to just acheive power. To have something different. I don't care if a VNT is the ultimate solution.

__________________
1987 300D 180k
1985 300SD 330k Helga
1992 300D Lola 269k- Sold
1986 325 coupe Bessie >300k Original engine(ODO Broke) sold
2006 2500HD Druamax Linda- Tows boat and looks pretty in garage thats about it

Clearly.

Polarisrmk: Yes, don`t let these be empty words and show us the goods when you are done

FI: That looked like a real turbo on the last one there with a/w IC. That one with the ALDA installed would be nice, cuz i guess it develops some real black smoke otherwise if not easy on throttle.

You are leaning me over in the right(simpler=better) lane here.

Is that a type of turbo you can get salvaged for a reasonable price, and what is it called? you have a dynochart for that car, or another myna-car with VNT? interested to see at how low revs the max torque is compared to conventional turbo. (hx40 shadowmaker is 2500ish.. i think)

If I want a used vnt suitable for a 400hp 603.. From what size of engines are we looking to take those turbos from. Thinking of HP and CCM. Any preffered turbo that is "good, fairly cheap, easily available" among the tuners?

Whan I see used turbos for sale i wonder why is it for sale? what is wrong with it.. It feels so easy to buy an already trashed turbo. who is selling a perfectly working turbo, unless the car is crashed? Just some thoughts..

There are many different types. Modern engines are using them much more often and g@ssers may start using them in the next few years as metal technology develops.

Here is a Myna 603 with a normal wastegated turbo.


This is the dyno of the VNT equipped one shown before.


The GT3788V from the 6.0L powerstrokes or HE351Ve from 6.7L Cummins would be perfect. The HE351Ve are common as dirt and just as cheap on ebay. The vast majority need nothing more than carbon cleaned from the vane ring and are otherwise brand new.

For sure, thats the first thing to ask them. I never consider buying a turbo unless they have a picture of the compressor wheel and it appears undamaged.

Many sellers know diddly about turbos and "no side play" to them is anything not scraping the housing. I recently bought a GT2256V on eBay that was describes as "perfect condition". When I got it the thing had so much in/out play that it would scrap the housing and I discovered the turbine side was melted.

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So then, this...

...is what the "adjustable vanes" in the turbine side of a VNT looks like...

__________________
1984 300 Coupe TurboDiesel
Silver blue paint over navy blue interior
2nd owner & 2nd engine in an otherwise
99% original unmolested car
~210k miles on the clock

1986 Ford F250 4x4 Supercab
Charcoal & blue two tone paint over burgundy interior
Banks turbo, DRW, ZF-5 & SMF conversion
152k on the clock - actual mileage unknown

After its been melted with extreme exhaust temperatures.


This is what it should look like.

How are you regulating those vanes?

Oh! Oh! Oh! Let me take a guess...

The shaft of each vane has gear teeth on the other side of their mounting plate and there is a ring with teeth around the interior circumference that meshes with the teeth on the vane shafts. The ring is spring loaded to rotate CCW to turn the vanes into the low-speed position, directing all the exhaust gasses directly into the turbine wheel for quick low RPM spooling.

I'm guessing that there is probably a pressure operated actuator (similar to the one for the wastegate on a stock turbo) that rotates the ring CW against the spring tension to turn the vanes to the high speed position, and direct the exhaust gasses more toward the outer part of the turbo housing so that the turbine wheel doesn't over-speed at higher RPMs.

Does it work something like that Forced?

__________________
1984 300 Coupe TurboDiesel
Silver blue paint over navy blue interior
2nd owner & 2nd engine in an otherwise
99% original unmolested car
~210k miles on the clock

1986 Ford F250 4x4 Supercab
Charcoal & blue two tone paint over burgundy interior
Banks turbo, DRW, ZF-5 & SMF conversion
152k on the clock - actual mileage unknown

Long explanation: I use a vacuum actuator and a wastegate actuator. The vacuum actuator has its internal spring removed and its connected directly to the vacuum system. The wastegate actuator is connected directly to the intake manifold. The stock vacuum control valve (used with automatics) varies the vacuum sent to the actuator. The wastegate actuator limits maximum boost and the vacuum actuator reduces maximum boost based on engine load (throttle).

Short: Wastegate actuator connected to the manifold. Vacuum actuator connected to the vacuum system.

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I know I'm showing my ignorance here (never have taken a turbo apart), but would it be possible to add fixed vanes (or something like them) to the inside of a stock turbo housing to direct more of the exhaust gas flow right into the turbine to improve the lower rpm spooling? Or is it a case of there being just no room for that kind of thing?

__________________
1984 300 Coupe TurboDiesel
Silver blue paint over navy blue interior
2nd owner & 2nd engine in an otherwise
99% original unmolested car
~210k miles on the clock

1986 Ford F250 4x4 Supercab
Charcoal & blue two tone paint over burgundy interior
Banks turbo, DRW, ZF-5 & SMF conversion
152k on the clock - actual mileage unknown