Impeller pic links are below.
I've been thinking of a gear change to reduce my 4.10's to 3.73's or even 3.42's. I pull my boat some (~3000 lbs) and would very rarely pull more, maybe up to ~5000 lbs. I would like an extra mpg if I could get it and I would love to reduce the noise & rpms while running down the highway/interstate.
I've read that the 6.5 is most fuel efficient at 1800 rpms, however as my truck drives now, I think it would struggle to stay in OD when at 1800 rpms.
Don't get me wrong, the truck runs great, after all the modifications it is a totally different truck. It really seems to take off at 2100 rpm and up. With my current setup running steady on flat ground 55mph I've got 1 psi, 60mph 2psi, 65mph 3psi. I got to thinking maybe my turbo is worn to the point boost doesn't build until later than normal, so I took a look (and a picture) and here is what I found.
impeller pic 1
impeller pic 2
impeller pic 3
Could the wear on the impeller cause the boost to be lower than normal at any given rpm? Or does the computer sense the lower boost and close the wastegate more to compensate for a worn turbo?
[ 09-22-2004, 02:33 PM: Message edited by: Big Red Suburban ]