I read elsewhere that the little s300 shafts that are very common obviously are actually larger than the big K31 style shafts?

S300 = phat shaft

K31 = Aurora5000

????

 

So you're inferring that because they're "similar" in size, that the shafts between the A5K and K31 are identical?? Maybe a call to ATS would tell us for sure...maybe!

PourinDiesel...where are you. Care to measure your A5K vs. your K31 and tell us for sure?

Chris

 

There is more to strength than shaft size...

And no...the S-300 based turbos (Phat or not....LOL) have much smaller internals than K31/A5k's.

Looked hand in hand a month back...

 

i was crusing ebay yesterday and came across an add for a k31 brand new in box for like $225. now my question is it stated its the turbo used on a detroit series 60 motor. are they serious? thats a huge motor and i had no idea those turbos were the ones being used by some of youll on here

brett

 

Yep...and the Series 60 isn't all that big. Only 775 cubes. The big CAT's and Cummins are all near or over 900CID!

Chris

 

Where could you have read that??

I bet we'll bet to the bottom of it over here.

 

Maybe I should just call Bullseye directly as they seem to be the largest maker of these turbos...?

 

Identical.
This is very true..

Thats what we are using but we use a smaller hot side housing to match drive to our displacements.

The shaft of the K31/A5k might in fact be smaller than the S300 but I dont either way, but I doubt it is. I will say however that my S300 66/71 lasted 6 months before it had a thrust bearing failure. I currently have an Aurora 5000 that is K31 based from ATS and I have been pulling with it for 2 seasons now and there is no sign of it failing or wearing out.

S300's are great but dont last very long. K31's, S400's are more suited to the competitors and people that dont like to buy a new turbo every 6 months.

Here is a Aurora 5000 (left) sitting next to the "phat shaft" it is replacing (right):



'nuff said!

 

I guess we can assume the bearings are more stout and the shafts might be of a better material. That is a huge turbo. WOW!

 

not to hi jack the thread but how much fuel do you need to light the a5000/k31???