Turbo + Super at the same time

[stefanzhr]

I heard someplace that it is possible to have a turbocharger and a suparcher in one car at the same time. Is this true?
If so, would it be possible to have twin turbo and a super in the same mkIV supra?
Any additional info/ opinions would be useful.

P.S.- I'm still a NEWB.

[projectsupramk3]

Yes twin charging is entirely possible and has been done many times in the past, but it's very expensive and it's very hard to get it to work correctly and efficiently. Just stick with one or the other, since the car is already turbocharged you might as well stick with those.

[stefanzhr]

Why is it so hard to do?

[TcmaBoy]

I don't see why its harder to setup a compound system VS any other set up. The only reason I see is that you would have to go to a stand alone engine management system. You wouldn't be able to cheat the stock ECU with a piggy back system. However if you are looking at a serious upgrade piggy back systems won't do either. With any major (by major I mean big changes in boost levels) change to your engine be it turbo or supercharged you have to fabricate new parts such as intake and exaust manifords, and you would have to have a new ECU put in seeing as how Toyota ECUs are not reflashable. Compound boost offers the best of both worlds. Roots blowers give great low end, and the turbo would just bee spooling up as the SC runs out of breath. I don't think this would work with a centrifugal SC though. Seeing as how a centrifugal blower is just a turbo compressor with a belt drive in place of the turbine. I remember reading about an MR2 in a magazine using the 3L v6. They combined the MR2 turbo system with the TRD blower for the V6 with excelent results. The fabrication and tuning is really not all that different with what would be involved with a big boost turbo project. Folks are just used to seeing off the shelf kits that just bolt right on. The company that developed the kit has already done the fabrication and tuning for you. Most of these either come with a "chip" or work within the factory ECUs limitations. They are also made for cost. If there was a demand for a compound kit I'm sure there would be one, but the cost of a new turbo and blower would put it in the custom work price class any way. If you are going big you need big money, and if you are in the big money class then why not consider compound boost. Another option is the screw blower. They cost, but they give the low end response of a roots blower and don't peeter out at the top. There aren't many out there either.

[stefanzhr]

Thanks for the info.

What stand-alone unit would you most reccomend and what the heck is a screw blower?

[TcmaBoy]

Its also known as a Whipple charger. This is because Whipple Industries is the bigest maker of them. You have 3 types of super chargers.
1. Roots type. They use rotors to force air into the intake manifold. The air is presurised in the manifold itself. They are the most common. The TRD kits are all roots blowers made by Eaton. They are not the most efficent, but give good low end performance, but have a poor top end.
2.Centrifugal. These are basicaly just a turbo with a belt drive instead of an exaust drive. Great top end, but no low end.
3. Screw blowers. Screw blowers use a pair of augers to presurise the air in the blower case. Think of a pair of screws side by side (hence screw blower) turning in synch pushing the air back in the case and thus presurising it. They offer the best overall efficancy. A screw blower can provide great low end, and they don't run out at the top.
Screw blowers are great. Its just a matter of finding one that fits your application. Whipple is mainly dedicated to the USDM V8 crowd. Centrifugal blowers have exploded because turbo companies merely have to dip into their already extensive compressor lines to create them. Where as a roots or screw blower would have to be developed from scratch.
Now when it comes to a stand alone engine management system there are a ton of them on the market. I would look for somthing that alows a laptop interface in real time and a data log capability. That way it can be tuned to a simple air fuel ratio in your driveway. Then if optimum power is desired, or if it is running rough you can take it to a dyno shop and have it fine tuned. Another important thing to look for is a self learning ability. This means that the ECU will watch the engine and fine tune itself over time. Make sure that what ever software it comes with is easy to use. Detenation monitoring is a must. I would also look for the ability to monitor multipule oxygen sensors. With this ability you can mount them higher in the exaust manifold and watch only a few cylenders with several sensors instead of them all with one. This helps with troubleshooting. It will help narrow down a rich or lean condotion to only one or two cylenders. Something like the HKS F-CON V Pro should fit the bill. hksusa.com Hope all this mess is of some help.

[JekylandHyde]

HKS also made a "Twincharge" set up for the MKI MR2. The twincharge was both super- and turbochargers.

Do a google on "twincharged MR2" and you will find gobs on info.