Rb25det ski race boat

[Bluejinx]

Hi all,

Just purchased my first rb25. I have been racing boats with in line six Holden engines for years and looking to upgrade (hopefully) to a boosted Nissan 6. I am currently working out how the marine conversion and will be running as close to stock rb25det to see if the boost will come early enough for a direct driven boat? Will it have plenty of low down and need top end? I'm not sure.. currently running N/A 202 Holden with around 300hp and max speed of 70MPH. Thought I would join the forum and get involved with the community for advice and sourcing parts etc

[GTSBoy]

It will boogy compared to the 202. You will need to properly intercool it. I'd go with water to air on a separate loop to the engine.

I think it is a highly strung kind of way to power a boat though. More cubes (ie big V8)  better than more boost, unless you have both.

[KiwiRS4T]

Jet boaters over here use the VH41 but I guess for skis you don't need as much power...

Oops just saw you are racing - more is better...unless you have a capacity limit.

[Bluejinx]

I do have a capacity rule, 1.7x for forced induction and have to be below 5000cc. If trials go well and the engine platform shows potential, then plan is to go to 2.8 stroked rb. I race short circuit ski sprints and boat only circuit races. Hopefully engine can spool up quick enough for a competitive launch and top end has enough torque and hp to get the mph

 

[PranK]

I love boats and I love RB's so i'm totally down for this. I'm super keen to see how it plays out - are you planning on keeping a build thread?

[PLYNX]

A 300hp holden 202 N/A engine is a very good power out put for that motor.

I know cause I cut my teeth on the Holden 6 for many years and am working on an ongoing supercharged nostalgia project.