Look at this 3L!

[mtnrgr]

0

 

[z3ro]

That seems kinda dumb. Wouldnt the spool time for the turbo be longer because now it has to wait for the RPMS to jump for the supercharger to push a lot of air?

And going with that, it seems like it would bog down at idle

 

[fleck]

Right, I'm thinking the exact same thing. There's got to be something wrong or useless about such a significant amount of power loss during power transfer, or something scientific having to do with vacuums, physics and electronics. Help me out here, knowledgeable people.

 

[z3ro]

Its pointless, thats basically all you have to know

Turbos work by taking exhaust gases and spinning a turbine, which in turns pushes more air into the motor

Blowers/superchargers work the same way, but with the use of a surpentine belt

Both have downsides

Turbos take a few k in the RPMs to fully spool and get the best gains. Also, a lot of the turbos product (compressed air) is thrown away through a blow off valve (releases excess pressure)

Supercharges also need a few k RPMs, and can only spin as fast as the crank, resulting in less gains

So basically, you have a supercharger which isnt going to do anything till around 3k RPMS, pushing air into a turbo, which is run off of exhaust gas, which sucks in more air, in this case from the outside (air filter), and from the supercharger.

Seems to me like:
A) you we need huge injectors for this set up, as with stock injectors you would run super lean
B) its pointless. Basically, your putting a crutch in the exhaust, for no reason (turbo manifold)
C) this setup would get EXTREMELY hot. your pushing hot air back into the motor, resulting in not as much net gains as possible. You would probably need some sort of methanol injection, or water injection (yes, you can inject water into the motor, with no problems) to keep the Air temps down



All in all, its one big waste of money for a decent length you tube clip

 

[rurouni20xx]

well this is an idea that has been done and has been proven to work, it involves computer programming and relay box timing tho. under full dump (70-100% throttle) the computer can be set to dump a short blast of nitrous to boost rpm and help spool the turbo, then once a certain rpm is reached (turbo fully spooling rpm) the nitrous is shut off and the turbo takes over. this has been used in drag race and some drift vehicles numerous times. its an interesting concept but if you really want to get your turbo spooled faster you can make like a centrifugal clutch and put on the turbo, then attach like an electric motor or something to prespool the turbo then when optimal rpm for the engine to take over is reached the turbo overspeeds the clutch and disengages it from the electric motor pulley. id do the nitrous thing but the emotor might be something dif to try. ive seen super over turbo setups b4 and they do work just not as well as you would imagine for the money.

 

[Rico]

Porsche uses a model of turbo that has variable boost. It's made of titanium and the fins inside the turbo adjust according to the heat made which delivers boost consistently from low all the way to high rpms. If only I had one of those.

 

[rurouni20xx]

thats too much shit to go wrong, ill stick to the good ole wastegate and wait a few secs to spool up. that turbo is prob thousands of dollars and technically experimental. not dogging porsche they make awesome shit, but i would hate to have my turbo fins stick in a certain position after a while and the motor run like crap.

 

[Beef52751]

6.0 Powerstrokes have variable geometry turbos as well, the fins inside the turbo fluctuate to make desired boost. There are things preventing the fins from sticking, although it does happen. When the truck sits at idle you can hear the turbo spool up and down (especially if its straight piped) to keep the fins from sticking, it also does it while cruise is set going down the highway. There is also a shit load of oil running through the turbos. Pretty good setup for a stock style diesel, but i wouldnt care to put it on much else.
Beef

 

[jasonrobo02]

Variable vane turbos are not anything too new. However, they are seen mainly on diesel engines due to the lower EGTs that diesel engines produce. The higher temps from a gasoline engine don't mix well with the current VNT turbos.

Also, a lot of the turbos product (compressed air) is thrown away through a blow off valve (releases excess pressure)

This is untrue. The blow off valve only operates during a rapid closing of the throttle and is used to prevent compressor surge which can actually break your turbo. I'm going to guess that you're mixing up a BOV and wastegate. A wastegate works by diverting exhaust gas around the turbine when a set manifold pressure is reached. The only thing that would cause a turbo to "throw away compressed air" in a detrimental way to the engine would be a boost leak at a coupler or something.

That seems kinda dumb. Wouldnt the spool time for the turbo be longer because now it has to wait for the RPMS to jump for the supercharger to push a lot of air?

Superchargers have ZERO lag. They are positive displacement, so for every rotation of the crank, they output a fixed volume. There is no way this will result in delayed boost threshold.

 

[4x4fun]

Superchargers have ZERO lag. They are positive displacement, so for every rotation of the crank, they output a fixed volume. There is no way this will result in delayed boost threshold.

X2

 

[z3ro]

sorry, i misspoke.

#1 correction: Wastegate, not blow off valve

#2 correction: Your right, they don't have lag, but they do rob the motor of power

 

[rurouni20xx]

my problem w/ this setup as i have been watching it a few times is the fact that hes using the super to help spool the turbo, fine, but after the turbo takes over, its pulling air past the super, which in turn uses the super as a flow restriction, and actually skrews the turbos efficiency cuz its not pulling as much air. its just way too busy and needs to be one or the other. its interesting but at the same time very flawed.

 

[bobbywalter]

this is a case where i would use a alum block 302 and 353 stroke it.





fawk all that turbo plumbing...

 

[Beef52751]

even if it does run inefficeintly, im sure that there are still substantial gains

 

[Beef52751]

Bobbywalter, I agree with you, i think an all aluminum 397, would be SWEET!!!