reddevil

Willing to bet a few dollars here but a positive displacement SC will not feed another positive displacement SC...... I tried both ways.....

Scott-EP

that doesnt mean ----. sinister has been trying to turbo a car for years and that hasnt happend. does that mean it wont work.


that just means that you couldnt do it.

before everyone gets back on the its pointless so dont do it bandwagon. im not condoning it, cause i think its a waste of time, but i bet it will work and it will be interesting to see. just llike the twin turbo LS that was posted here years ago

txdohczc

teah its going to be a waste of time and all but atleast the kid isnot asking a ---- load of dumb questions wasting your time. so ---- it let him waste his time either way i wanna see it

reddevil

Postive displacement into positive displacement does not work. Neither in series or in parrallel. I did both.

Now replacing one of the positive displacement pumps with a centrifigal pump, and it works great.....

turbo4life

i think you dont fully understand the whole cocept about higher octane

b18.

I don't think you fully understand the concept of SARCASM.

78NOVA

so where you sitting at with this project? i wanna see some more porgress on this pig. damn i cant wait to get my build underway. im getting antsy just thinkin about it.

bitchM0VE

Two SC's in parallel would be a 2 stage compressor. These are common. They work by the first pump compressing air, cooling it, then further compressing it. Any turbocharged or SC'd engine is a two stage compressor as the engine itself is a compressor. The reason it works is because the first pump is larger than the second.

Putting a pair of same size SC's in Series (one pumps air into the other's inlet) wouldn't do ---- because they both move the same volume of air. Now putting a larger blower blowing air into a smaller one would work, as that's a two stage compressor.

Now putting a pair in parallel is different. They will be working together. Esentially it's just one. Well it's still two but it's two little ones doing the job of a larger one.

The SC's will both take air at atmospheric pressure and compress it. Then cool it and it goes into the engine. Now ideally I would put a singe 1.6-1.8L twin screw SC and be done. It would be more efficient and a lot simpler. However they're expensive and hard to find while these 1L SC's are 35 bucks each and I can get them locally at the junk yard.

I've done the math, believe me. I know it will work and make boost. It will make my car faster. Now will it be ideal in every way? No. Ideally I would have a 1.6ish L SC. With a pair it's essentially putting a 2L SC on a 1.8L. You have to carefully study the compressor maps and make careful calculations to estimate how many CFM of air the engine will need at a given pressure ratio and snout speed. Then having two makes things more complex.

In short this setup will suck at low hp low boost. It's super inefficient on paper. These blowers are designed to turn 1.5:1 with the engine yet I will start out spinning them 1:1. SLow snout speed and a high pressure ratio = inefficient with this setup. They will only move about 70% of the air they should at 6500 snout speed (70% V.E., not talking about adbiatic or any of that. ). The motor turns 2 RPM's, ask for 1.8L, and the SC's deliver 70% of 4L so that's 2.8L of air. So were're talking a little over 8 PSI boost. That ain't ----.

But now let's pulley them to 1.5:1 and hit our target 10K snout speed. Now the SC's are up to 94% V.E. Motor turns 2 RPM's and ask for 1.8L, SC's pump out 94% of 6L so that's 5.64L. That's 31 PSI of boost. This setup kicks *** all of a sudden.

My setup will be somewhere between 1:1 and 1.5:1. As you can see 50% more snout speed moves a lot more air.



Now of course that math isn't spot on as it omits several efficiencies and variables that change with different PR's, snout speeds, and CFMs. But it gives you an idea of this setup's potential. On paper it looks like this setup will do 30 PSI pretty easy, but in reallity those SC's are not ideal for 30PSI. They will make it, but they will heat the air a good bit and use some HP doing it.


But if you know something I don't besides "it won't work, I tried it", I'd like to hear your reasoning. Seriously. I don't know you but you say positive displ. into positive doesn't work. That statement is wrong as hell. That alone makes me question your I tried it statement.

reddevil

OK, hard to say anything other than "I did it, it doesnt work" cause thats what happenened.....

Anyway, I had two clutch driven m62 SC installed. I tried them in parrallel and in sequence. Neither setup worked. Thats what I know. Techinically blowwer into blower worked, but it caused the belt to squeal like mother ****** and only made mediiocre boost over stock.

reddevil