Has any one thought of Teaming up a centrufical supercharger with the turbocharger.

[Huff N Puff]

A company called Procharger makes centrufical superchargers that can deliver upto 2200CFMs at about 35psi They look pretty compact,and hooking up a belt to drive one looks alot easier than plumbing twin turbos to me. I was wondering if any one out there has tried such a thing. One problem has been bothering me, and that is once the main turbocharger spins up to max effiency will the super charger restrict it incoming flow. My thoughts are that because it's centrifical the main turbo would pull right through it. If any one out there as any suggestions or insights,please share them with me. Merv

 

[sdalton]

didnt they do that in some fighter planes of WWII. I think they were successful

 

[MLee]

super/turbo

yes there was an aircraft but i din't know which one. the 903cummins V8 was set up this way. but was not as efficient as the regular turbo engines. in these it was just one more thing to go wrong.

just me penny's worth



Marv.

 

[GWDiesel]

A good thought,It brings to mind A 8 V 92 GMC diesel blows through a roots supercharger with a big turbo(big for it's size)

The roots blower would have more power loss than the Cent.

charger! The GMC 2 cycle Inline 6 Stationary eng. of years ago

(not a 6-71) had just a cent. super without a roots blower and

made good torque. It sounds like your thought is worth a try.

good luck if you try! GWD

 

[24VChev]

Belt driven blower

Volvo Penta diesels in boats have this exact same set up. It uses a clutch just like an A/C pump. When you hit the throttle out of the hole the belt driven blower kicks in to help build bottom end boost. Once boost is up to a certain point the blower then shuts off via the clutch then the air is routed around the blower by a flap type gate and the engine is running on the turbo alone. These engines are about the same displacement as the ISB and pump out about 350hp or so.

 

[Hohn]

ATI Prochargers are good products, but like all other superchargers, they less efficient than a turbo. The Whipple-style superchargers are the most efficient, and do a a good job of compressing with minimal heating of the charge air.



Diesel engine would be the LAST candidates for a supercharger vice turbo because their limited rpm range makes it much easier to size a turbo that will work properly.



A gasser might rev to 6500. To keep from choking at the high rpm, the turbo is laggy.



The narrower rpm band of a diesel makes is more appropriate to a turbo-- you can size it for quick spoolup without choking at high rpm.



The main reason you also don't see the combination often is that it isn't as efficient as a properly sized turbo. A turbo uses wasted energy (exhaust heat) for a power source instead of stealing HP directly from the engine



A typical engine only converts about a third of its potential to actual RWHP. One third is lost in mechanical inefficiency, the other third is wasted in the form of exhaust heat.



If a turbo can recover 10% of the energy from that exhaust and convert it to work, then you will see (10% of 33%) a 3. 3% increase in engine efficiency.



A standalone turbo is also a much simpler setup then a combination turbo/supercharger. In rare cases, it may be appropriate, but by and large, there is a reason that it doesn't appear very often.



HOHN

 

[Huff N Puff]

Wouldn't the supercharger help the turbo spoolup quicker

Has any one seen the eRAM electric superchargers they claim 750CFMs my thought is to fabricate a Y for 2 in parallel which would keep the same pressure about 2psi and double the volume, feeding the turbo. You could play with micro switches relays and resistors to vary the flow with throttle opening. The nice thing is they are relativly cheap,and compact about 500$ for a pair.

 

[Idaho CTD]

The supercharger may not flow 2200cfm at the rpm's available in a diesel application though. Sure if you bypass it when the big turbo is rolling it will work but it kind of like building parrallel twins. It's a lot of work and not many if any have tried it. I guess someone has to be the guinea pig so I say go for it

 

[aviatorman]

Belt drive Centrifugal Huffer

The turbo charger currently equiped on your truck is centrifugal by design, as is the belt drive supercharger. The difference comes in the driver of the compressor. One is mechanical and one is kinetic conversion of hot gas into rotary torque force. The system you dream about won't work because of differential volume output of the two devices at any given RPM. One will always lead or lag the other. Using two turbo's is the cheapest and most efficient way to huff your way right into orbit.

 

[johnjackson]

Superchargers and turbos will work in conjuction. I had a ten wheel dump truck with 350 hp Detroit two stroke V-8 with exactly that setup. Ran like a stripped ass ape.



Also, about 6 months ago there was a thread, guy claiming to have a bunch of boost at idle. Next post was yea, right. Then next post was easy here, better look at the guy's sig. He's running a roots type blower. Then whoa, tell us more. Never heard another word. BS?? Be interesting to know what happened to the roots blower guy.



John

 

[andrewkoperdak]

Your idea is in application in the marine diesel catagory. Detroit 149 (16 cylinder) uses four turbos and two roots blowers to make the power. These are two strokers and the blowers help blow the exhaust out of the cylinders. I am not really sure how well this setup would work on a 4 stroke. But the blowers help keep the turbos spooled at a higher rpm so that they can take the load of the propeller loading and unloading as the ship pushes through the swells.



We use yet another setup on another pair of marine diesels. The MTUs (German marine diesels rated to 3450 Hp each) These engines use a triple turbo combination. One turbo or two will be online depending on loading. Each turbo gets progressively larger. No more than two turbos will be on at a time. To accomplish this the engine uses dampers to isolate one or two turbo exhaust ports. If any of you older guys remember 12 inch vinyl records than you can imagine the size of the turbos on these engines. These things sound like jet engines when the final two turbo stages kick in. Just incredible noise.



Just my two cents worth.



Andy

 

[JR2]

I recall seeing a picture of a truck that Dave Smith had in Idaho... it had some sort of blower on it...



I always thought it was a good idea, have a blower get you to 10 psi and then let the big turbo take over. 5 psi at idle would be cool.

 

[Hohn]

FWIW, ANY two stroke diesel HAS to have a supercharger, otherwise there's no positive pressure to feed the charge into the cylinders.



This is the link:http://auto.howstuffworks.com/diesel-two-stroke1.htm



So, yes, you can combine turbos and supercharging. But this is a Detriot-style 2 stroke, and I thought we were talking four-strokes? On the 2-strokes, the supercharger is not so much a power booster as it is rquired for the engine to operate. The turbo is the power booster.



There are a lot of sophisticated multi-turbo setups, and there are infinite variations.



But the fact remains that the cost/benefit goes dramatically DOWN when you start to get into such complicated systems. I mean, look how much more expensive a set of twins are compared to a single, yet they are MUCH simpler than some of the setups you have described.



IMHO, though, twins ARE worth it in the cost/benefit analysis.



HOHN

 

[dresslered]

There's Throttlejockey over at Dieselram.com using an Eaton MD 112 supercharger. I never did see any pics though. :{



http://dieselram.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=2;t=000506

 

[andrewkoperdak]

Hohn,



Pardon me... I was not suggesting that 2-strokers and 4-strokers were the same. I was merely attempting to add to the knowledge base. My point being the technology is there to make it work.

Like you mentioned, there isn't any economy putting a blower with a turbo. Our large Diesel 4-strokers would have them if it was worth the extra cost. Take MTU, they decided that multiple turbos was the route to go.



Andy

 

[redram]

Hohn,



Not ALL Detroit Diesel two strokes are supercharged. 3-71's, 6-71's, 8-71's, 12-71's, 53 series, etc are not all supercharged. Many have turbos but a 2 stroke does not need to be supercharged to work.



They work better when turbo'd but it is not a requirement for them to work.

 

[Hohn]

thanks for the correction. The article from the link I posted made it sound like ALL two strokes had to be supercharged to work.



HOHN

 

[TxDieselKid]

Originally posted by dresslered

There's Throttlejockey over at Dieselram.com using an Eaton MD 112 supercharger. I never did see any pics though. :{



http://dieselram.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=2;t=000506

Yeah, that's why I take that thread to the top every couple of months.

 

[RustyJC]

Since 2-cycle engines (not just diesels) do not have an intake and exhaust stroke, there has to be some provision made for scavenging the cylinders during the period when both the intake and exhaust ports (in the case of a ported engine) or the intake ports and exhaust valve(s) (in the case of a Uniflow engine) are open. This means the scavenging air manifold pressure must be higher than the exhaust manifold pressure - otherwise, there's no scavenging air flow through the cylinder.



The simplest and least expensive method of scavenging is that found on 2-stroke motorcycles. Crankcase scavenging uses the bottom of the piston to pump air from the crankcase into the cylinder. Unfortunately, crankcase scavenging prevents the use of conventional pressurized lubrication systems with the crankcase acting as the oil reservoir.



Larger 2-cycle engines have used such scavenging air devices as separate scavenging air cylinders (sometimes integrated with the crossheads on integral engine/compressors) and centrifugal, Roots or other types of blowers (note - these devices that pump scavenging air are not called superchargers since they do not elevate the initial compression pressure in the cylinder substantially above atmospheric pressure. ) It was common practice to augment these blowers with turbocharging from the mid-1950's onward. Note that, due to the back pressure of the turbocharger's exhaust nozzle ring, air could be trapped in the cylinders at pressures substantially above atmospheric pressure, so these turbochargers were indeed supercharging the engines. These engines could be series turbocharged (for instance, the turbo discharged into the inlet of the centrifugal or Roots blower) or parallel turbocharged (the turbocharger discharged into an airbox as did the scavenging air cylinders - with a check valve to prevent reverse flow. )



In the case of 2-cycle integral engine/compressors (natural gas fuel, spark ignited, port scavenged engines), our company did away with the parasitic losses associated with gear-driven centrifugal blowers and went to pure turbocharged engines in the late 1960's. This still produced the problem of how to get scavenging airflow when starting the 2-cycle engine and when it is running at light loads. To accomplish this, we use the turbocharger as a scavenging air blower for startup and at light loads. This is done by admitting compressed air onto the impeller blades to spin the turbocharger up to a speed sufficient to produce enough airflow for starting and unloaded operation - a process called "jet assist". Once the load comes up, there is enough exhaust energy to drive the turbocharger.



Regardless, some means must be provided to pump the scavenging air through a 2-cycle engine.



Rusty

 

[therabbittree]

most detroit diesels that are 2 stroke have 2 or 4 valves per cylinder and those valves are not intake valves they are all exhaust valves. . the 2 stroke detroit uses a supercharger as a intake valve to force air through the cylinder ports with out the supercharger it wouldn't run. so basically the the supercharger is intake valve. these engines are called naturally aspirated with the supercharger for that reason . . the forced induction ones use a turbo to supply boost.

later

deo

\x/ hillfolk!