A random thought about twincharging...
 

Back when I had my AW11 MR2, I remember that the supercharger had a magnetic clutch to turn the whole thing on or off. I'm thinking that in a twincharged setup, we could do something like run the supercharger up until around 6 or 7 PSI, at which point the turbo would take over and we could simply turn off the supercharger.

The setup would probably require one-way check valves on the output pipes of both the supercharger and the turbo, to prevent positive boost from one system from entering the other system. I've also thought about something like this instead:

https://www.miataturbo.net/attachmen...ine=1333400308

edit: the last image should be turbo < super PSI, lol.

Basically the bypass flap would prevent the turbo as well as the supercharger from seeing positive displacement from the other system.

Anyways, this all came about because I realized how much extra room I'd have in the engine bay after dropping AC and PS... just something fun to think about.

What do you guys think?

You and Falcone need to get together and :makeout:
https://www.miataturbo.net/diy-turbo-discussion-14/find-me-turbo-fits-these-critera-64606/

I think a properly set up turbo system will outperform a supercharger system at any rpm.

I agree... I'm thinking this is more for someone who wants to build something with a massive turbo and keep their low end. TD04s need not apply.

If you're serious about a twincharged configuration, why not just run the turbocharger and the supercharger in series (air filter -> Turbocharger -> Supercharger -> head) and use the supercharger's internal bypass valve (which is normally open only at idle and light cruise) to bypass the supercharger once the turbo is spun up and making boost?

Quick spool valve? This idea comes up once in a while and usually goes nowhere. If you want to do it just for the neatness of it, then by all means go for it. It would be pretty cool to see. However, I think that a properly sized/tuned turbo only setup will be more effective and certainly easier to build/fabricate.

This seems like an entirely doable idea... someone with a coldside kit should be able to rig something up easily. I don't know if those include a pulley clutch though, i'd still want to be able to turn the SC off above a certain PSI.

Would running all that air through the SC itself cause any issues, flow wise? We'd be aiming to use a rather large turbo i assume, and i don't know how well all that air would flow through a bypassed SC.

How about running the sc into the compressor side? Then use a bypass on the sc that starts to open at preset rpm/psi?
Would the sc help with spool? However minuscule?

Mass air -> sc->turbo->IC->intake.

Either way, torture test-track for air...

I remeber an Opel Manta with Volvo engine that did just this: SC at lower rpms which disconnected in favor for a turbo up high.

I'm at work, so I can't look for it, but search for "Opel Manta Hilmerson" and I'm sure you'll find something.

Use a regular turbo feeding into a positive displacement supercharger. And just put in a 1 way valve between the two for when the turbo is off boost. Using a MAP sensor this would work.

This set up actually compounds the boost; if the turbo was running at 6psi before, and the SC is setup for 6psi, you will see boost pressures over 12psi. Remember that this is using a positive displacement SC that will move a certain volume of air per revolution regardless of pressures involved. The heat added into the air is also compounded at the same ratio as the boost so a massive incercooler is necessary.

I'll dig up some more info on this once I go to sleep and wake back up lol

A certain model of the jdm nissan march uses a twin charge system from factory. There is also a newer vw also uses it. You could look into how they set up their systems.

For motorsport nitrous and other systems are proven to work.

For daily I dont think it would be reliable enough.

Compound turbo charging sounds more inteesting...

Of course one could always spend the kids' shoe money and run a twin-scroll turbo and a pulsed header...

A member (I think it was 1Hot4Pot) of TurboFord.org did just this using a Holset HX35w and reported lower spool times/rpms. HX35's are big. The motor was a 2300 sohc 2 valve with a decent, not great, flowing head. Most 2.3 hx35 combos were spooling from 3-3500. IIRC 1Hot reported 2800 or so with the pulsed header.

Then there's the VNT/VGT route, or just build a 9:1 motor and use less boost 'til the engine really gets turnin'.

Supercharger setups are more reliable than turbo systems anyway. It would be a complicated install but I see no reason why reliability would have to be sacrificed. Check out the information here and calculate theoretical HP figures for a twin setup:

http://horsepowercalculators.net/tun...ncharged-setup

Yes, obviously.

I mean, how could a huge device with lots of intricately-machined interlocking parts, a belt-drive system, and its own self-contained lubrication system possibly be less reliable than a much smaller device with only one moving part which is externally lubricated and has no gears or belts?

It's just basic logic, really.

I got sidetracked thinking about this the other day too, here's too diagrams I found of the vw tsi engine

https://www.miataturbo.net/attachmen...ine=1333579352

https://www.miataturbo.net/attachmen...ine=1333579352

heres another using the SC's bypass valve, would want to make sure that was big enough not to choke the flow of the turbo. Seems like this wouldn't be the best solution if you're using the sc to spool a big turbo.

https://www.miataturbo.net/attachmen...ine=1333579352

The placement of the turbocharger bypass valve is more optimal in the Audi illustration.


I'd need to see some kind of documentation from VW explaining why they would re-engage the SC at high load. Unless they have undersized the turbo and thus require the additional compression of the SC to achieve maximum boost (which would be stupid) then this doesn't make sense.

Google the wiertech emno twin charged civic. That thing is amazing and built very well. over 300whp on low boost with a d16 SOHC. It runs extremely quick in one lap of america and time attacks in Ontario. Someone should build a turbo/FFS set up. Or build a custom coldside manifold mount with an integrated air to water in the manifold.

https://www.miataturbo.net/attachmen...ine=1333579352

This is pretty much what I'm planning but without an IC between the turbo and super.

You could snag a supercharger off an old toyota previa mini van. We used one a while back to back yard boost a carb'd civic. They are small easy to mount and have an s/c clutch on the front so you can turn it on or off.

I'd thought going with a m45 and a bigger turbo.