Super efficient FI setup for bottom end?

**stonebreaker** · 05-19-2006, 07:13 AM

Oh, and as far as the turbos go, do you worship them or something? Are they not allowed to have any faults in your mind? Turbos have good points and bad points, just like 99.9% of ALL engineering solutions. They're not the answer to everything automotive, or they would already be on everything automotive.

**ericwilloughby** · 05-19-2006, 01:06 PM

Okay, so your right. It has 67 HP at idle speed. It does appear to have about 34 HP at speed. But only the Prius.

**Zakar** · 05-21-2006, 06:39 PM

Originally Posted by stonebreaker

I also don't know where you guys get this idea that turbos run off of "wasted" energy in the exhaust gas. .

a book called "Maximum Boost" by corkey bell..

**stonebreaker** · 05-21-2006, 07:01 PM

Uh-huh. So, if the turbo is running off of "free" energy, why does the bsfc of an engine go up when you turbocharge it?

**Zakar** · 05-21-2006, 08:47 PM

Corky Bell, has 27 years of experience with forced induction design. Corky has earned an engineering degree from Texas A&M, and authored two books on forced induction "Maximum Boost" and "Supercharged". Bell has designed over 90 forced induction systems, of which over 15 are currently in production.

..

**stonebreaker** · 05-21-2006, 10:14 PM

That's nice, but you didn't answer my question. A naturally aspirated engine that has a bsfc of .50 will typically have a bsfc of .65 or higher when turbocharged.
http://www.precisionturbo.net/techinfotext.php?aid=22

So where does that extra 3 ounces of fuel per horsepower go? I contend that it goes to run the turbo. The turbo does work in order to compress the air, do you agree? And in doing this work, it creates backpressure. If there is 20 psi in the exhaust system between the piston and the header pushing on the turbo, then that means there is 20 psi in the cylinder, too - and in an LS1, with about 12 square inches of piston area per cylinder, that's 288 lbs of pumping loss the piston has to overcome.

It's like the adage "You have to spend money to make money." If you invest 20 bucks and make 150 back, that's a fantastic investment - but you still had to spend the 20. In this case, that initial investment manifests as a higher bsfc.