I have a Rogers, 5.3 LS powered.
According to the impeller chart im making somewhere in the neighborhood of 400-425 hp on motor @ 5200 rpm, and about 600 on a 150hp shot spinning about 6200 rpm or so with a B- AT impeller.
The boat runs 70 on motor (repeatably have seen higher a couple times) and 85 on the bottle on GPS.
Heres where my Cavitation questions come in.
The Pump is a JC suction housing, Dominator Bowl, AT aluminum impeller. No inducer, no stuffer, everything is stock. Has a loader by GS i dont know what kind, and i believe a Backcut shoe. No Diverter, Full droop with a set of adjustable wedges. Wedges are setup at 3*up and i also have a rideplate. I dont know the angle of the rideplate somewhere around -3.75 degrees
Before the intake there is a pretty bad transition, think a Flat intake in a rounded hull. And not blended in. I have corrected this, but have not taken the boat out since.
I just put a brand new AT impeller in that was cut down for me to a B-, other than that the impeller is stock and non-detailed. I put a brand new non shouldered stainless wear ring in with this impeller. Clearance measured out to about .024" total. I did not check for runout. I should also mention, this was an issue before the new impeller.
If i flat foot it from idle, the boat will literally bounce off the rev limiter as long as i keep my foot flat (rev limiter is 7200). The boat does move and accelerate)
If i Flat foot it from idle, and i hear it come "unhooked" and back off the throttle, hold a steady throttle about half or so. Then stab it, its fine and pulls to my max RPM and holds
If i dont flat foot it, but get on it spiritedly wait til the boat planes then stab it she loads well and takes off pretty nicely. Will pull hard and run to WOT no problem
If i'm cruising from plane (say 3-3500 rpm or 45mph or so) and stab the throttle. The boat pulls to WOT and holds hard and accelerates very nicely
If i wait until the boat planes, and grab the Nitrous it hits hard as hell and pulls to the max RPM and the boat accelerates as expected.
Basically the boat blows the pump out from idle, but once im moving its fine.
I have a couple of thoughts, but id like to hear your ideas.
1. With no diverter, i go so bow up (from the droop/up angle) that it uncovers the jet intake, causing it to suck air
2. I need a stuffer
3. I need to buy a diverter
4. The transition into the intake was the issue, everything will be fixed when I take it out.
5. Im an idiot, and doing everything wrong
6. LS engines wont work in a jet boat
I have posted this on sjcb as well. And received some great ideas form them. I know a lot more people frequent this site so i wanted to hear your ideas also.
One person suggested it may be sucking air from the rope seals, they are new, but it amy be loose. The hand hole o-ring is brand new and tight