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dean1484
dean1484 UltimaDork
9/16/14 5:20 p.m.

Say you were thinking of putting both a supercharger and a turbo on you car. If you were to run them in series what would you put on first? Yes I have an evil plan brewing in my brain.

Putting them in parell is a whole different thread.

Swank Force One
Swank Force One MegaDork
9/16/14 5:22 p.m.

Believe you're supposed to put the supercharger closest to throttle body. At least... that's how all the positive displacement blower + turbo setups i've seen have done it.

mad_machine
mad_machine MegaDork
9/16/14 5:34 p.m.

that is how Lancia did it with their's

Feedyurhed
Feedyurhed SuperDork
9/16/14 5:45 p.m.

I thought you meant..........which gives out first with long term use.

MrChaos
MrChaos Reader
9/16/14 5:58 p.m.

I believe for twin charging it goes exhaust -> turbo -> supercharger -> intake

McTinkerson
McTinkerson New Reader
9/16/14 6:04 p.m.

Been reading this article have we? Either way, I fully support this endeavor.

Mr_Clutch42
Mr_Clutch42 Dork
9/16/14 6:06 p.m.

When you say in series, are you talking about which one builds boost first? Since superchargers run off the crank, it must( I think) go first. The turbo needs to be sized to the supercharged engine power level, not the N/A power level.

David S. Wallens
David S. Wallens Editorial Director
9/16/14 6:08 p.m.

I don't charge my supper. I pay cash.

dean1484
dean1484 UltimaDork
9/16/14 6:28 p.m.

In reply to Mr_Clutch42:

nope I was not thinking that but it is something to think about. I was thinking about bypass valves though. Would I need two of them to bypass things especially in the tube between the two units.

And would you want to use two intercoolers one to pre cool the charge between the units.

dean1484
dean1484 UltimaDork
9/16/14 6:30 p.m.
McTinkerson wrote: Been reading this article have we? Either way, I fully support this endeavor.

nope just me looking at stuff I have. I have been debating the merits of a sc versus a turbo. Then I got thinking why not both. Then of course I came over here.

dean1484
dean1484 UltimaDork
9/16/14 6:37 p.m.

If you really want a look at how my brain works I was thinking of using a oversized suppercharger to power a turbo. Why? I don't know.

kevlarcorolla
kevlarcorolla HalfDork
9/16/14 6:48 p.m.

I think the additional weight/complexity isn't worth it unless you wanted to run a stupid big turbo and help offset the lag by feeding it with boost from the charger.Not sure if in that scenario you'd want the clutch on the SC to disengage to lighten up the drag on the crank or if it would become to large a restriction.

The SC14 isn't exactly cutting edge and power potencial is likely only 200'ish before its the limiting factor,I'd ditch the sc and go with the right sized turbo for the application....cheaper/easier/probably better results/easier to tune/lighter/MUCH easier to pkg etc etc.

dean1484
dean1484 UltimaDork
9/16/14 7:43 p.m.

Ya I realize it will be less reliable and more complex and slower. But think of the cool factor.

Stop being so logical

dean1484
dean1484 UltimaDork
9/16/14 7:44 p.m.

Let your mind wander in forced induction nirvana.

Vigo
Vigo PowerDork
9/16/14 7:47 p.m.

You guys may think this whole thing is a joke but i actually plan to do this to my new Caravan.

Lots of stuff i plan to do never happens, though.

I think this one has a lot of momentum though since i've spent a lot of time collecting parts and purchased the current van almost wholly on the idea of how cool it would be to do this to it. No guarantees, still.

EastCoastMojo
EastCoastMojo Mod Squad
9/16/14 8:00 p.m.

You only need the suppercharger if you're running the Car-B-Cue. Otherwise, the turbo should be sufficient. .

Trans_Maro
Trans_Maro UberDork
9/16/14 8:00 p.m.

Gonna be cool if it stays together.

When the car gives birth to a pile of oil and shrapnel, be sure to post pics!

Raze
Raze UltraDork
9/16/14 8:09 p.m.

Your next challenge: Compound Turbocharging, which incidentally could be tacked on after you work out your current challenge...

Knurled
Knurled PowerDork
9/16/14 8:17 p.m.

I've been interested in twincharging ever since reading about it on eng-tips. It's supposed to make detonation disappear relative to a turbo engine of the same power.

The key is, turbo into blower. Blower into turbo makes zero sense because the blower is not a compressor, it is a fixed displacement per revolution air mover. Turbo compresses the air going into the blower, which crams it harder into the engine. If the turbo is running 15psi (2:1 ratio) and the blower is running "7psi" (1.5:1 ratio) then you wind up with 30psi manifold boost (2x1.5=3) but, and this is the kicker, the exhaust manifold pressure is only that which is required to make 15psi at the turbo. And since you effectively have a much larger engine, you can run a larger hotside which helps the situation even more. This means you can scavenge out the exhaust residuals, especially on a 4-valve engine, which not only adds VE but removes heat that you don't want, thus the greatly reduced detonation.

Supposedly, when set up right, you can get max boost across a VERY WIDE powerband, with next to no lag. The largest problem is finding room for all of the plumbing. Well, that and having a drivetrain stout enough to work.

I have no idea why VW did what they did. Or why Lancia decoupled the supercharger on the Delta.

jmthunderbirdturbo
jmthunderbirdturbo Reader
9/16/14 8:23 p.m.

You will need a boost controller for the turbo, and its pressure signal will need to come from the turbo outlet, not the manifold. otherwise the supercharger will open the wastegate before the turbo has a chance to build pressure. your turbo will need to be sized for enough airflow to cover the supercharged engine, +20%. this is because at ambient pressure, as the turbo crosses over from vacuum to boost, right at 0 PSI on the gauge, you will be flowing close to maximum pressure on the charger, and high enough in the RPM range to be close to max CFM on the motor. then you add pressure to the front side of the charger, and raise the CFM again. undersizing the turbo will be disastrous for the charger. its usually about 14-17% (at 10-13 PSI). i do recommend you pipe the turbo to an intercooler at a minimum, but an air/water cooler would be better, unless you go through the hassle of a water aftercooler for the charger. then a simple air/air for the turbo would be fine. the above post mentions greater heat loss, and less heat retention in the cylinder, but thats an advantage you will lose without proper charge air cooling. you will need to size your injectors to about 400% of the motors maximum requirements N/A. your fuel system and management will need to be up to snuff, and spot on. you will need a VERY big blow off valve for the turbo side of things, and and an even bigger one for after the supercharger. bending a throttle plate or blowing the valve retainers when chopping the throttle at higher loads is a very real possibility.

Let me know if you have any more questions.

-J0N

turboswede
turboswede UltimaDork
9/16/14 9:18 p.m.

I've thought about doing this as well. I've got a 2.0L SOHC and a Holset HX35 with an Eaton MP45 supercharger from a Mercedes. Unfortunately the electric clutch is long gone. Should be interesting to get it all installed and piped up. I'm looking forward to reading this thread as it continues :)

Trans_Maro
Trans_Maro UberDork
9/16/14 9:42 p.m.

HKS used to make a twincharger setup for the MR2 IIRC.

Shawn

mr2peak
mr2peak HalfDork
9/16/14 9:42 p.m.

I came here for something delicious, and this thread is delivering..

Go do a search on mr2oc, there's a bit on dual charging. I remember seeing diagrams of the HKS kit from back on the day.

Vigo
Vigo PowerDork
9/16/14 10:02 p.m.
I've been interested in twincharging ever since reading about it on eng-tips. It's supposed to make detonation disappear relative to a turbo engine of the same power.

I dont see how that makes sense. The only real advantage of compound turbocharging is to get a wider powerband out of an engine whose peak power level dictates an extremely laggy turbo. In general i would say compound setups are no more adiabatically efficient than an optimized 'normal' turbo setup, so i dont see how they would magically cure detonation.

Also, not sure if everyone is on the same page regarding compound vs other possible twin-charger setups. In a compound setup the blowers are hooked in series with the larger one blowing through the smaller one and the pressure ratio across the smaller blower is multiplied by the pressure ratio of the larger blower. That's how on a compound setup you can have a 600hp engine breathing through what would normally be a 400hp turbo or super.

jmthunderbirdturbo
jmthunderbirdturbo Reader
9/17/14 3:11 a.m.
Vigo wrote:
I've been interested in twincharging ever since reading about it on eng-tips. It's supposed to make detonation disappear relative to a turbo engine of the same power.
I dont see how that makes sense. The only real advantage of compound turbocharging is to get a wider powerband out of an engine whose peak power level dictates an extremely laggy turbo. In general i would say compound setups are no more adiabatically efficient than an optimized 'normal' turbo setup, so i dont see how they would magically cure detonation. Also, not sure if everyone is on the same page regarding compound vs other possible twin-charger setups. In a compound setup the blowers are hooked in serial with the larger one blowing through the smaller one and the pressure ratio across the smaller blower is multiplied by the pressure ratio of the larger blower. That's how on a compound setup you can have a 600hp engine breathing through what would normally be a 400hp turbo or super.

did you miss the post about heat? basically, to make your theoretical 600HP with a standard turbo setup, you would need the heat and pressure from the exhaust to generate ALL the extra airflow. with a twin charger setup, only roughly half the heat is necessary, cause only about half of the 600HP comes from the turbo. the exhaust side of the turbo is usually MUCH larger in this case, sized to match the turbo you would use for 600HP by itself, think 1.01 AR, as opposed to a .63 or .82, but the cold side is sized for only a fraction of that, say 60 trim, or even a 50 trim if the VE is right. the exhaust pressure is greatly lowered, as is the temperature of both the manifold and the valves/combustion chamber. this drop in heat retention almost always results in LESS detonation ('virtualy eliminating it' is a stretch).

DO it! and post pics!

-J0N

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