Shit box 308 powered jet boat project

[73crownwagon]

Yeh they at the back of the boat I only had 35 litres in today so maybe quarter of what it would be full and still struggled 

[Roman]

This thing is fucken sweet

Nice work 

[73crownwagon]

It's all a process of elimination now as to why it didn't have full boost. 

So today brazed the impeller tips up and re machined them in the lathe. Hopefully It makes a difference tomorrow for test run mkii

 

[73crownwagon]

Mkii testing successful. Was raining and cold but testing needed to be done. Engine still needs tuning but otherwise am happy at current state

[peteretep]

bring it camping auuuu

[flyingbrick]

How much did ya increase impeller diameter?

[73crownwagon]

3 minutes ago, flyingbrick said:

How much did ya increase impeller diameter?

 

.50mm radius. Was snug fitment. Squeeled like a pig for 30 seconds or so on first start at lake today had to do some self clearenceing 

[Evan]

Yeah I hope this is coming to Arapuni

[flyingbrick]

Crazy. I know nothing about these things at all.. just amazed at the clearance they require 

[73crownwagon]

@Evan 

[73crownwagon]

17 hours ago, flyingbrick said:

Crazy. I know nothing about these things at all.. just amazed at the clearance they require 

I to was amazed by how .5 of a mm made all the difference! I'm actually interested to learn more about pitch angle and impeller design now because obviously the smallest of changes make improvements 

[HighLUX]

Yeah impellor and wear ring clearance is a big thing with jet units, too much clearance and you get cavitation.

Dont get thrust from bubbles

[kyteler]

15 minutes ago, HighLUX said:

Yeah impellor and wear ring clearance is a big thing with jet units, too much clearance and you get cavitation.

Dont get thrust from bubbles

Michael Jackson would disagree. 

[HighLUX]

Bubbles didnt want thrust from

jacko

 

[Testament]

On 25/12/2018 at 07:49, 73crownwagon said:

I to was amazed by how .5 of a mm made all the difference! I'm actually interested to learn more about pitch angle and impeller design now because obviously the smallest of changes make improvements 

.5mm is 20thou

Old Barry machinist would drive a truck through that!

Heck the rough/getrdun guy at work was called ten thou ted sometimes

Only needs as much clearance as there is play in the bearings + 1x beesdick

So by the squeeling of your impeller it is now right. 

[UTERUS]

A+ yarn there Tom. 

[73crownwagon]

So had this out at Arapuni with the lads for new years. It ran ok still needs engine work just doesn't have the HP to boogey like I'd like it to. 

 

[HighLUX]

The answer is forced induction

[RUNAMUCK]

Belt driven inlet manifold pleez 

[BlownCorona]