Twincharger???

[Patrick Javert]

Has anyone ever thought of having a supercharger and a turbocharger on their engines before? this setup would use a roots-type blower to get low-end response with a turbo matched to the blown engine to spool up quicker and have large power gains at the top end. Does anyone think it could work? Yes, I do know it will be expensive, but any forced induction system is for our cars, especially since we have to get the custom made. Any and all comments welcome.

[camaro_zach]

Yes, quite expensive, and if done, definatly not a street car, lol. But god, it would be sick once its done.

[navyblue2000]

i've entertained the idea. it'd be hard and expensive, but you are right, the gains would be incredible. throw in some alky injection to cool the supercharger intake charge, and that would be awesome

[Defender24]

Ya, but the pblm is not putting both on the car, the pblm is whether your engine would support it. I have yet to see a 3.8 run 15psi of boost, much less the 20-30 psi you'd see out of that setup.

[Patrick Javert]

Once the turbo kicks in and surpasses the sc, the boost from the sc does not combine with the turbo. If the wastegate on the turbo is set to 15 psi and the boost on the sc is 9, the cars max boost will be 15 psi, not 24 psi. After the turbo reaches 9 psi, it just forces more air through the sc than it can pump. I've seen this setup on integra's before running low boost on stock internals. Thats the main reason I brought it up. BTW, does anyone know what the deck height of our blocks is and what the stock compression height is of our pistons? I'd like to know in case I'd like to stroke my engine out to 3.5/3.6 in. by lowering the compression height and/or by reducing rod length since we are not going to run much higher than 6000 rpm and I've seen engines run that have the same stroke as us run 8000 rpm easily.

[Dominic]

Something the military used to do was called a combined turbine engine compressor.

Basically you take a normal engine capable of handling immense amounts of ungodly boost - you tie a turbocharger to it but instead of mounting the output shaft to a intake compressor you mount it via direct-drive gearing right onto the crank... i.e. Exhaust gases spin the turbine and the escape of these gases pushes on the crank :D .

Then, you strap a supercharger onto that badboy - most likely a roots for them.

All in all you end up with a supercharger, which increases the combustion charge of the cyl, causing a superhigh amount of exhaust to be expelled, which is used to help turn the crank, which accelerates the engine RPM, and thereby pushes on the super faster, creating a higher combustion charge... you see the cycle :D .

It works extremely well - another little tidbit from my Navy book on internal combustion engine design :D

[Mike Mayron]

The supercharger would be a bad idea. If you had any turbo lag, N02 would help give you alot more torque down low then a supercharger ever could. Another plus is that it would cool off the hot air charge quite abit.

SC = Linear boost based upon RPM, so it's not going to have much boost @ lower RPM's
N02 = all @ once (single stage of course)
Turbo = Should build more boost sooner than a SC, but not as quick as no2. It all depends on the sizing of the exhaust turbine and the compressor aswell, but let's assume it was sized correctly for the sake of this discusion.

Another point would be that you could easily drop the compression and crank up the boost for much less then a supercharger plumbed into a turbo setup. It would be much more reliable and powerful aswell.

Just my $.02