Where can someone find a good resource on twincharging?

[Majik]

I'm looking for a resource to answer some questions about twincharging using a roots style blower and turbocharger. I've been trying to find articles on it but most just immediately dismiss this as a bad idea. I'm looking for instant throttle and torque down low with the power top end. While my question is general in nature. I'm trying to understand the nature of a roots blower once it recieves a pressurized air stream and how it deals with it. Trying to determine at what level does it become a restriction to the system. Some have sugested to mount the blower remotely and then try and engage and disengage it with an electro magnetic clutch assembly. In my application this setup will not fit into the packing so all the way to redline the supercharger will be active. Also will the roots blower compress an already compressed turbo air or will the compressed air just be heated by the blower. I realize this is a very noob question but information on these systems is very sparce or maybe I haven't looked in the right direction.

 

[Blownbuick98]

ZZPerformance did this on a newer bodystyle Grand Prix with great success.

http://www.zzperformance.com

 

[amorrison]

I believe that the P-38 Lightning did this in WW2.
A big top secret idea at the time.

This is an interesting topic - I hope it gets a lot of traffic.

I hope the following sites are useful for the current SoA of this idea and equipment availability.

http://www.halfbakery.com/idea/Supercharger_20_2b_20Modified_20Turbo

http://www.petrolheads.co.uk/gassing/topic.asp?t=205696

http://en.wikipedia.org/wiki/Twincharger

http://www.geocities.com/MotorCity/Lane/1231/twincharging.html

http://www.answers.com/topic/twincharger

http://paultan.org/archives/2005/08/27/volkswagen-super-turbo/

http://www.greencarcongress.com/2005/08/inside_vws_new_.html

http://forums.beyond.ca/showthread/t-58774.html

http://www.automotiveforums.com/t417.html

http://paultan.org/archives/2006/05/15/2006-international-engine-of-the-year-awards-results/

 

[Methusalah]

HKS made a Twincharger system for the supercharged Toyota 4AGZ as fitted to the early MR2 and Corolla.

It added a Garrett T4 turbocharger to the standard Toyota roots type supercharger, which entailed various relief and bypass valves etc.

Sadly it is no longer available.

 

[globi5]

If you own a Subaru STI, you'd only need to buy this kit and you're all set:

http://www.forcedairtech.com/turbokits_wrx_stage5.html

 

[DBUTTOCOVOLO]

At one time, Detroit Diesel (still may?) turbocharged through a roost style blower on its 8-71.

The compressed charge from the turbo will heat up the blower enough to change the housing/rotor clearances. To allow for this, you will have to increase the clearances which will reduce the blower's effeciency.

 

[Fabrico]

Detroit Diesel does this on several ranges of 2-stroke engines. The 92 Series (92 cu in per cyl) have a turbo feeding into a blower that has a bypass valve. The blower is active at idle so throttle response is very good. The blower bypasses at cruise and becomes active again upon demand for full power. Parasitic loses from the blower are minimized with this arrangement. Intercooling is done by a compact air/oil unit mounted directly underneath the blower.

Turbo's can bypass, so can Roots type blowers. Your idea (or mine) may get dismissed by some here as well, but I think it can work splendidly.