i dont intend on running a procharger. again a procharger is designed like a turbo. giving better boost and cfm at higher rpms. its a mid to high powerband supercahrger
i want to run a screw or roots style. more reading brought me to 6-71 and 8-71 superchargers. while the 6-71 was diesnged as a diesel application the company talks about nothing more then 10psi in gas motors being a limit and how compression ratio is key. unlike diesels this is not the case. we can run 21:1 Compresion ratio and be ok. ie 6.9/7.3 idid (yes i have a 6.9 with a ats turbo and it works great. memery severs on the 21:1 ratio
The efficiency of a traditional blower like you are referring to here is HORRID. Bare in mind at all times, what you are trying to achieve is not pressure itself. Pressure is just a means to allow you to increase the density of the intake charge. If the pressure is completely offset by enormous increases in temperature with a stupid flat-faced rotor slapping against the charge air trying to push it out, while it rushes back in, beats the sh*t out of the rotors, so on and so forth, then you're just chasing your tail, and eating up a LOT of horsepower spinning the wee out of the damn thing for tiny gains in actual density...
now the roots style supercharger (6-71/8-71) actually doesnt compress the air in the supercharger it compress te air in the manifold, while the scre (whipple) compress the air before it is fed down into the manifold.
Yes. The classic straight rotor supercharger is simply a pump. It pumps X volume of air and "stacks" it up in the intake manifold where it compresses at the discharge of the unit. Horribly inefficient. Try like 40 to 60%.... maybe...
The "whipple" is actualy what is called a Lysholm type compressor. It uses screws to gently compress the air along their length. This produces a much smoother compression, and allows for a much smoother introduction of the airflow into the engine's manifold. Instead of a constant beating with hammering pulses of flaming hot air, the lysholm sends a smooth flow of air out the screws. This is also why they are so much quieter.
again this is form the company that bolts the superchager to the manifold liek i was originally going to do. but now i want to feed the air to a turbo. so that mean the roots 9-71/8-71 superchargers may be the best bet. i was worred about a 60psi system blowing a SC up. but since the roots actually will compress the air between the turbo and the SC this means it should be capable of 60psi without hurting it.
If you are talking about placing the unit ahead of the compressor inlet of the turbocharger, then I just can't see this being a smart move. The supercharger is only going to move X CFM per rev, while the turbocharger will draw a wildly varying amount of airflow depending on engine power output and engine rpm. In other words, if you placed a boost gauge between the supercharger and the turbocharger, it might read out 5 to 10psi off idle, and with low throttle settings right on up to higher rpm. But as you started standing on the throttle and exhaust energy started going up as more fuel was introduced and more energy went across the turbine, the turbocharger would start building boost of it's own, in essence making your ____ cubic inch engine 1.5, 2, 3 or more TIMES that size in terms of the CFM flow into that turbocharger compressor. When you got on the pedal, you could actually watch the boost gauge between the blower and the turbo drop to zero if the turbo was even moderately sized and you had the fuel flow to support it. If you had a boost/vac gauge, you could probably watch it swing to the vac side...
I would never place a constant displacement unit
ahead of a variable displacement unit. No dice. It's just going to get in the way.
also with the roots it said id you are to over spin them (gas models running 6k+ rpms) that the air will heat up and actually making it act like a NA motor (from my understanding is the hot air expandes and i assume (drops the psi rating) even though the SC still spins and prushes air. all its doing is forcing more air (but not compressed air) into the cylinder.
This is the horrible efficiency of the units. When you overspin them they get so inefficient that the heat offsets the gains through pressure and leaves you with nearly the same density, but with much more heat and pressure. Pretty much the worst thing you can do to help the engine out. Same basic amount of oxygen coming in, but more pressure and temperature to try and tear things apart for no good reason. It doesn't move any more air, it just beats the sh*t out of the air it's drawing in so much that it heats up, makes more pressure and sends flames out the discharge.
so een if it was to max at say 3000rpms. it wouldnt give the turbos more air it woudl give it the same amount of air that the turbo would normaly feed if the supercharger wasnt there.
It's actually more likely that the turbo would be
worse off once it was up on boost trying to get air through a restrictive intake air heater.
iv been looking around the 6-71 and the 8-71 would cost me about the same as a 4.0 whipple and seam to be a small high unit and feed form the top of the SC. granted screws are more effesent then roots i like the idea of roots more i read about them. also the current duaramax in the diesel mags was running a 8-71 or was it a 6-71 i dont have the mag in front of me and it seamd to work well . i think i might try the 6-71 due to i the fact its a tiny bit smaller and i dont want it to be underpowered at lowe rpms. i dont care for the sc at top cuz a big turbo is what will produce that power.
You need a lysholm type if you want to make power. If you want something for nostalgia, get an old weiand. And a larger blower is only going to make more low end boost when pullied the same. And if you place the supercharger ahead of the turbo, it has every chance of completely stifling the turbocharger to death, killing all the top end power it was supposed to make because it's pulling a vacuum through a flame thrower.
also on the fact about how much energy it take to spool a sc vs a turbo. research shows that a twin kit (current diese tec mag) say a ats 5000 turbo will produce said hp. when switch with a ats 3000 and ats 5000 the boost might have been a couple psi higher but the hp was dropped.
Obviously if the engine could support the 5000 as a single, then adding a
smaller turbo was only going to help broaden the powerband, not make more at peak...
Now if they compared the engine power with a 3000 as a single, vs the 3000/5000 compound setup they would have shown something worth seeing.
due ot the fact that turbos are not free engery and require so much hp to spin. so the way i see it 1SC and one nice sized turbo should yeild in the same hp loss but will creat better off the line proformace.
The turbine makes use of thermal energy that the supercharger throws down the toilet. The hp loss will be greater. And off-idle performance is only limited by the strength of your bottom end on a well sized and tuned turbocharged engine.
now with the vgts. what to say i couldnt run a properly sized vgt with a turbo
this should provide a good lowe boost at cruise and the max psi when at wot. yes?!
Yes.
the procharged kits from empire ran a PC and the stock 6.0 turbo. i know my truck doesnt really feel like the turbo hit max till 2000rpms anyways but iv never really seen what the top enf proformace feels like past about 3000rpms. (only drove mine for under 2weeks and didnt play with it much)
i am realy thinking about playing with the idea and testing this out with a 6-71 and a stock turbo jus tto see how its sized. maybe tryign out new turbos with wastegate and blow off valves to make sure i wont drestory everythign during testing. theres not much info out there. hells there not much on the PC let alone dyno spec's. the reason i want this is cuz i spend most of my time babying my truck. never letting it hit high rpms. i love racing at lights and all i want is to beat any ricer and most corvetts and mustange at lights, why you ask because i am still very young and like to do that kinda stuff. i am looking for something that will provide me with the most amount of tq at bottom end and SC is the way to do that.
There's really no need. All you will do is punish the engine, spin the tires and then fall on your face when it really counts. A turbocharged engine would come out of the hole just as fast, and then leave you like you were sitting still up top and continue to pull away from you when it mattered.
If you just want to fry some tires at slow speeds and act tough, then what you're describing will probably pull the wool over most people's eyes.
also i like different, and to be different. im not afraid to test thing out and if all fails. ill buy or rebuild my 6.0 and probably just try compunds but i want to try and be different first. i i love going ot car shows with smethign different, i always have *back in highschoiol i had a 71 baja louder then any vett and the local burger joint car shower every friday night. one night we went mudding with my bro and his jeep. showed up covered in mud and they all wondered how a 7in clearnace bug could handle what a 4in cj and 31in tires could handle, i said becuase hes only got 7in of clearnace from ground to diff. my car weight maybe 1200lb totaly his weights 3k. i might have 60tq but i have no weight to sink into mug, and my all terrains worked in the top side of the mud. i also cleared the trails faster then he did. im just into things that make people rethink. if i can have a supercharger and turbo charger truck i can just throw that into muscle cars faces. most vetts were i am from will run turbos cuz they provide better top end, but they all envy SC classic and whish they could get top and bottom end. thats what i want, and i want to throw it into there faces and say i did this from scratch not just throw a kit on
I think I might get you to rethink the love affair with torque for starters, lol.
Pumping the turbocharger into a lysholm type compressor then into the engine would make more sense to me.
But good luck whatever you try.
