KKK K3T 3070MGA Turbo

[razmrtwo]

Hi guys, I bought a KKK K3T 3070MGA turbo for a steal last week. Yes, I know its an old type of turbo but it is perfect for my 3SGTE However when I opened up the turbine housing, this is what I found out



Need your advice if the turbo can still be use?

[alanmr2turbo]

im no expert but i would say it's in need of a rebuild

[Steve-O 2007]

dont people "Clip" the blades?

[Steve-O 2007]

My turbine is clipped. The blade tips are trimmed (clipped) back - this means they are less of an obstruction to exhaust gas flow. Just like making the sail smaller on a boat this means that you need more "wind" to get any movement (hence the slight delay in spool as exhaust gas volume needs to be higher to spin the wheel). All turbos saturate eventually and our stock turbo exhaust housings are relatively small and restrictive - thus you lose flow at the top end and power drops off. Reducing the obstruction by porting or cutting back the blades increases the saturation threshold a bit so top end torque is higher than unclipped. This sounds like a cheat but on my car I have a lot of low end torque and it does well for a small turbo up top. Owen Developments rebuilt my 19t (was Ashoks) with Garrett wheels as they are more robust when being clipped than stock Mitsubishis - also ported and polished housings. I haven't got a figure for how many degrees or mm's of clipping they did but I know that being over zealous with the lathe can really harm low end spool - best done by people who know exactly what they are up to. I really couldn't say what the effect would be on a diesel but in theory the torque band moves up the rev range. Are diesels meant to be revved hard?

[Steve-O 2007]

Clipping:
Clipping is the technique of cutting away some of the material on the fins of the impeller wheel of the turbocharger. In other words, to 'clip' a turbo is to make the fins in the exhaust path smaller. The cut is usually done at an angle of between 10 and 20 degrees - the bigger the angle, the more material is removed from the fins.

This may seem like a dumb thing to do, since smaller fins mean that the exhaust gases will impart less force to the turbine wheel and consequently increase turbo lag. This is true, but the benefit of clipping is found in the high RPM range of the motor. At higher RPMs, the turbo may have already surpassed the required user-set boost levels and is not contributing to engine power.

Since the impeller wheel in the exhaust stream partially blocks the exhaust gas flow (by design), it can act as a significant restriction at high RPMs, when the exhaust flow rate is highest. Clipping the turbo reduces this restriction and allows more air to flow past the turbo wheel at high RPMs, thereby improving airflow through the engine and increasing top-end response.

[alanmr2turbo]

But surely you would clip ALL the blades not 2 or 3 of them as this would make the turbine unbalanced. Spin this at upto 100k revs which they do and im sure it would not be long before it self distructs then it can be bye bye engine.

[bobhatton]

That has had it, put it in the bin

[razmrtwo]

im no expert but i would say it's in need of a rebuild

Changing the wheel and re-balance it?

[razmrtwo]

But surely you would clip ALL the blades not 2 or 3 of them as this would make the turbine unbalanced. Spin this at upto 100k revs which they do and im sure it would not be long before it self distructs then it can be bye bye engine.

This is what exactly I had in mind mate

[razmrtwo]

That has had it, put it in the bin

I am sure u're talking about the wheel right? I am not gonna bin the whole turbo into the bin mate

[NoddE]

Dont know if you saw my post on mr2oc, i didnt see this until now but this is what i posted there:

You can have the right person rebuild the blades (add material by welding) and then grind away excessiv material. I had this done to a turbine wheel on a rare IHI turbo (RHX6).

The guy needs to know what he is doing though and use the right material on the material added.

btw, the turbo i got fixed looked alot worse than that, all blades were ruined.