Quote:
Originally Posted by Ardent
 Nice!
Would compounds on a more ordinary, lower boost gas engine be an effective means of broadening the RPM range at which boost is available? Perhaps this is one of the reasons for what you're doing; however, with everything else going on. . . I'm not sure!
I am familiar with the use of compounding as a means of achieving multiplicative levels of boost in diesel applications (perhaps yours too?). |
Nice question.
This is one of the things I wanted to find out when running a gasoline turbo compound system.
What I have found so far is at normal freeway speed the compound setup acts like the single turbo set up. So no gain and no loss.
Where the compound system has improve FE is acceleration from a dead stop.
The car acts like a very large engine thats running a very small turbo that gives me boost at off idle.
I can run it in lean burn from the dead stop and accelerate up to the speed limit with no intake pumping losses now. With the large turbo before when it was a single turbo system it would have turbo lag and get terrible FE from a stop. The single turbo wouldn't start making any boost until around 4500 rpm, and thats way to high of a rpm for FE. Now I have boost at 1500 rpm. This also helps with my low compression engine. I would love to run a higher compression engine, but I can't because of the dual purpose of the build FE/High Performance. I'm making around 500WHP on pump fuel. Well pump fuel with waste solvent.
The thing I don't know and bugs the crap out of me is what would happen if the compression was higher??? Would it knock from a dead stop with the compounds instant boost??? IDK.
What I do know is this thing is a major turd when I blow a charge pipe off. To the point I think I killed the engine. I think my Insight would out run it.lol
So, yes to your part of the question "broadening the RPM range"
When at low rpm from a dead stop running around 8 psi of boost it helps and I think it would work for a down size engine that needs more power that would run at 14.7 A/F instead of my 18:1 A/F lean burn.
I also think we will see some DEP Divide Exhaust Period systems in the near future. This is something I would love to try in the near future. I'll save that for another post