Supercharged & Turbo'd

[Powder Extreme]

Just wondering out loud, why wouldn't it be possible to put a Roots type supercharger on one of these motors? Setting for a max boost of 8 - 10 wouldn't drag much hp at all, and you could run a big turbo housing to keep temps cool. One problem I could see with a roots type is the turbo pressure would have to be blowing through the supercharger blades. Not sure what that would do to intake temps.



Next question: belt driven centrifugal "Paxton type" blowing into turbo inlet, again would eliminate lag and only need to be dialed into a maximum of 10 psi. I would think that would be much easier to plumb in then twins.



In the 70's my dad had a semi with what they called the "Screamin Dozen". 2 stroke Detroit Diesel V-12, twin superchargers, twin Turbos. Same motor the Bandag Bandit had in it if anybody remembers that truck. 750 driveline snappin horses. Dunno about torque, well over 2000. So... the two types of blowers can work together.



Anybody????



Jerry

 

[Lurch]

As I recall, all the charged/turbo'd engines were 2 strokes, thereby needing the positive pressure. However, I allways thought it would be an interesting experiment also.



Lurch

 

[Powder Extreme]

I was just sitting here thinkin the same thing, a 2 stroke would need positive pressure wouldn't it? But I still think it would be possible.

 

[Turbo Tim 1]

Not trying to start a fight but what are you guys talking about when you say a two-stroke needs the positive pressure? And if that is true does it only apply to diesels? I know there are millions of two stroke gas engines without blowers and/or turbos.

 

[Big_Daddy_T]

superchargers

i met a guy with a supercharged cummins. he wanted to sell it to me. he bought it for a boat and then sold the boat but kept the motor.

 

[Ray Torresdal]

supercharged Cummins

Cummins had a supercharged engine for trucks years back. As I recall it was in the 180 Hp. range??? We repowered an old IH gas tandem with one, had 8 speed Roadranger behind it. I made several trips to Milwaukee hauling cows to the stockyards with it. That would have been '69 or '70. The truck was old then, and heaven only knows where the boss found the engine.



Ray

 

[RustyJC]

Originally posted by turbo tim1

Not trying to start a fight but what are you guys talking about when you say a two-stroke needs the positive pressure? And if that is true does it only apply to diesels? I know there are millions of two stroke gas engines without blowers and/or turbos.

Industrial 2-cycle engines are not crankcase scavenged like motorcycle engines. They have standard bearings, oil pumps and carry oil in the crankcase just like a 4-cycle engine. This is required for acceptable strength and longevity for industrial applications.



Because of this, the combustion air must be pumped to the power cylinders at a positive pressure. Crosshead-type engines can use the power pistons to provide scavenging air. Other 2-cycle engines have used compressor crosshead pistons, a scavenging air compressor cylinder, an oscillating blower, a Roots-type blower, a centrifugal blower running at 20x engine speed, etc.



Basically, any of these configurations can be turbocharged. My employer has built 2-cycle engines for the oil and gas market that combine turbocharger(s) with just about all of the systems described above except for the Roots-type blower, and GM has taken care of that. P. S. - when using a blower in conjunction with a turbocharger, the turbocharger generally discharges into the blower, not vice versa.



We've also built pure turbocharged 2-cycle engines that don't use a blower. To start these engines, the turbocharger(s) are spun up with starting air to pump enough scavenging air to start the engine. This "jet assist" continues along with retarded ignition timing (dumps more energy to the turbo) until the engine gets enough load for the turbocharger(s) to become self-sustaining.



Rusty

 

[Mark_Kendrick]

You could use this in a twins set-up



Run a nice big turbo. . and a centrifugal charger set to about 14 psi.



the turbo is installed like factory but feeds the supercharger before the intercooler. . out of the charger into the intercooler.



It would be screamin fast off the line and capable of huge boost levels.



I wonder about reliability??



boost levels of 100psi would be easily achievable. the lack of lag would be worth the minor inefficiency of the super charger.

 

[Speedo]

turbo plus blower

The 2-stroke Detroit Diesels utilize a blower to supply enough air

to run as a normally aspirated engine. When a turbo is used to

increase air flow it pushes pressurized air into the blower. There

are times when a charge air cooler is used between the turbo and

the blower but more often they use an aftercooler that uses the

engine coolant through a heat exchanger that sits below the

blower to cool the air. Some of the later versions of these engines

use a by-pass blower that takes the blower out of the loop once

the turbo is spooled up.

 

[TxDieselKid]

no more money till I can jam....

Originally posted by Mark_Kendrick

You could use this in a twins set-up



Run a nice big turbo. . and a centrifugal charger set to about 14 psi.



the turbo is installed like factory but feeds the supercharger before the intercooler. . out of the charger into the intercooler.



It would be screamin fast off the line and capable of huge boost levels.



I wonder about reliability??



boost levels of 100psi would be easily achievable. the lack of lag would be worth the minor inefficiency of the super charger.

Mark, your just full of good ideas huh? Just get a cam if you want to lose the lag.



This doesn't "sound" to bad, other then the bill longer then the Mississippi River itself.



But would be oh so fun off the line!



Think about the cost Andrew!



The sound of all that spooling up, and pushing that much air



So much to think about when trying to spend so much money!:-{}



Andrew-trying to save for a new guitar rather then BOMBs...

 

[Mark_Kendrick]

It's cost prohibitive at 3-4k for a supercharger. . but lots of fun to think about.

 

[WestTN]

super & turbo

The Detroit Diesels were a bit different. They had valves in the head and a port in the side of the cylinder. This configuration required the blower to fill the cylinder.

 

[Reb.B]

i was thinking the same thing. i talked to J. Donnelly about it and he said it would rob top end HP. BUt if u were u set it to max out at 2000 rpm or so and have it really cranked at low end, it would have to haul a$$. Like Mark said, u could then install a huge turbo, cause there wouldn't be any lag. Something else i've been pondering is what Jap racers are doing. They are putting little electric motors to spin the turbo at idle right before they take off. Sure would like to figure some kind of early boost.

 

[TxDieselKid]

Originally posted by rebsram

Something else i've been pondering is what Jap racers are doing. They are putting little electric motors to spin the turbo at idle right before they take off. Sure would like to figure some kind of early boost.

i think that Turbotronics might have something like what you want!Oo.



Andrew

 

[Powder Extreme]

Like Mark said, the super at 3 or 4 grand is kinda pricey. But that is for the whole entire kit, plumbing etc. Maybe we could buy just the blower for a couple grand. A friend of mine is a dealer for several different blowers, I'll have to ask him about it. Maybe even get a rebuilt for pretty reasonable.

 

[Powder Extreme]

Some more food for thought. To get away from robbing top end hp, what about using something like an air conditioner clutch. Have it set to disengage over 2000 rpm or something like it. Hmmm this is really sounding like a winter project

 

[Mark_Kendrick]

then you'd have to force air through it... would probably cause a restriction.

 

[tgbol]

A centrifugal blower still needs to spool up to build boost, granted you spin it from the crank so it isn't load dependent. A GMC blower is a positve displacement pump so it will force the same amount of air through it at each revolution. Now adding a turbo to the mix kind of supercharges the supercharger. It will work but you are going to build a ton of heat in the air by beating in the turbo and the blower. There was a Top Fuel car in the 70's that tried it. Twin turbos through a 6-71 on a 392 Chrysler.

 

[Powder Extreme]

I realize the centrifugal still needs to spool up. But you could change the pulley size so it is blowing a few psi at idle.



Speedo mentioned a bypass blower how would that work?

 

[ralphr]

I am sorry but if I remember memory is the first thing to go! a fewyears back I read an article about either volvo or an italian outfit equiping yachts with this kind of setup, advantage power thru out the rpm range, less smoke, no turbo lag. if I remember had some fancy controller to switch intake from super charger to turbo depending on rpm boost etc. just can't remember the engine manufacuter, mabey mann?