Regardless of cost and feasibility and common sense, is it technically possible to both turbocharge AND supercharge an engine?

I was thinking about this on my ride home today, and came up with lots of 'maybe ifs' but no concrete solutions. Anyone know?

 

Sure, why not?

Well, here's why not. Here's where feasibility & common sense enter...

1 - There may not be enough room in the engine compartment for both.

2 - Superchargers & turbochargers you can actually buy, want atmospheric pressure on the inlet side. You may have to get something made custom. $$$$$$$

3 - You still have the same limit to how much boost before something explodes, so you probably won't get any more power vs. either turbo or SC alone.

 

It's been done.

Unfortunately, the main issue that arises is that you're adding a lot of heat into the intake tract, and usually the supercharger is in line after the turbo, so the efficiency RPM range is about the same as if you had the supercharger running at higher boost all alone.

On a 4 cylinder, I would just stick with a turbo. I've never been impressed with supercharged 4 cylinders. On engines with more cylinders, sure, superchargers/blowers are great for making power and simplifying plumbing issues, but turbos are generally much easier to tweak to generate more usable power across the band.

 

That's pretty much what I figured. I had, in my mind, the idea of multiplying boost levels... but the heat problem, leading to efficiency problems, makes it not worth it. Interesting, though, that it's been done before.

 

I think i've heard mentions of setups, where ppl will spray nitrous, for low end torque, until the turbo spools, and then takes over for the upper revs, anyone heard this?

-PHiZ

And what's the deal with sequential turboes. I think, one is calibrated to spool low RPM, and the other at high. However, when the high rpm is spooled, I would imagine the low-rpm turbo is causing an air restriction... I can only imagine they are a bitch to tune....

 

This is done all the time to help spool a turbo. The added heat generated by a nitrous burn helps make enough extra exhaust energy to build boost earlier than it would unassisted. Of course, with a proper sized street turbo tuned for high power, you'll build too much power for the amount of traction you usually have anyways... The way sequential turbos are normally plumbed, the smaller turbo usually is a restriction, but not so noticable that it kills it's purpose. Of course, with advances in turbo shaft bearings and such, sequential and twin turbo setups are largely pointless. Sequential turbo setups are better left for bi-turbo Maserati street cars and the like from the early 80's and before.

 

Ahhhhhh.... Maserati.....

I saw a Merak for sale in the local paper, for $35K. Dammit, why am I not a millionaire car collector..... >

 

Yes u spray the n2o before the turbo spools up, helps kill that thing known as turbo lag, so u dont let the competetion pull away from u during the intial spool up, plus u can get nitrous directly injected into the intercooler which drastically cools the incoming dense air mass to gain even greater hp since n2o is so cold upon changing into a gaseous state,

and on the turbo question its kinda the same idea, u use a smaller turbo to wind up quickly and give u quicker response and immediate pull forward, and then a larger turbo to take over and create massive quantities of boost once its fully reved and uve already got ur traction which takes over for ur little turbo which is at this point just dumping away excess pressure, while making a wonderful hissing sound.

 

so does twin turbo make sense in a 6 or 8 cylinder configuration, with a turbo for each bank of cylinders? Does that configuration exists anywhere? I wonder how tricky that would be to tune, hrm.

Direct port injection into the intercooler, that is different than a intercooler, sprayer, right?

-PHiZ

 

That's a parallel turbo setup, and is quite common.


Intercooler sprayers spray onto, not into the intercooler.