Originally Posted by
SteveH
I was chatting to a guy at pod with a compound charged drag bike (hope to see them again this year, nice blokes) and he was explaining all the details of how he did his. I forget all the details now but he was saying how blowing one into another created a ratio of 3:1 for boost ie 1 bar +ve into the other turbo created 3bar +ve in the larger turbo. I seem to remember the reason being a small turbo will reach 1 bar (and thus create 3 bar total) faster than one big single turbo?
Thats all from memory though and I could have got my wires crossed
I have no personal experience of compound charging, only information gained from others who have done it.
Fundamentally though the basics seem to be:
- The large turbo wont make as much power as it would without the smaller one also present
- The small turbo wont spool as quickly as it would without the larger one present
- You'll make more power than the small one could, and will spool quicker than the large one can
- unless you are wanting to run huge boost pressure (the 3 bar you mentioned wouldnt even be the low boost setting on some compound charged competition diesel motors!) its very unlikely you will be able to better the spool and power of a well matched single turbo.