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Further updates:

We've done few modifications to the oil galleries in side the bearing housing hopping for less oil drag on the balls, as well as separate oil feeding setup for the comp side collar. Feels very smooth to spin.

Following some advises, I've added anti surge slots onto the comp housing. In theroy it reduces pressure resistance to comp wheel while acts as additional suction ports once boost hit. So the general benefit would be faster response and quicker spool time. Hopefully it works as expected.

comphousing.jpg

compturbo.jpg

This time its a ATR43G3 duel ceramic ball bearing unit. I'm hopping for 300rwkws with very fast response.

I hate when my balls drag in oil too.

:P With out oil balls would be cooked.

I'm hopping to get 300rwkws around 18~20psi, and expecting to see 20psi by 3500RPMs.

:P With out oil balls would be cooked.

I'm hopping to get 300rwkws around 18~20psi, and expecting to see 20psi by 3500RPMs.

That type of response would really be attractive, whens the test tune happening?

Putting it back into the car today. If every thing goes as planed should have it tuned the week after.

Also we are in the process of designing a duel ball bearing profile for OP6 high flow. Which has the capacity of 320rwkws with GT3076's response while looks stock standard. I will post photos of it when manufacturing process begins.

Hey mate if you already have a atr43g3 what kind of costs would be involved if you wanted to upgrade to this turbo? Assuming everything goes well with the testing

To get that comp housing with the surge slots to a ATR43G3 assume you have the .60 comp will cost $260. or just $100 to drill the slots if you have the .70 version.

Upgrading with ceramic ball bearing cartridge would cost way too much at moment.

I’m still exploring the actual benefits of having those ceramic balls and try to get them to work at their peek efficiency. We will be able to build them at an acceptable price with small batches. I will announce the final price after having a mature product.

So with just the surge slots are you saying you will get faster response and quicker spool time? If so how much better compared to what it is now?

Surge slots wont really make a difference unless the turbo is surging, it actually decreases the compressor effeciancy because it bleeds off air, it doesnt suck air through the holes, rather it releases air.

Surge slots wont really make a difference unless the turbo is surging, it actually decreases the compressor effeciancy because it bleeds off air, it doesnt suck air through the holes, rather it releases air.

Not all true. engine normally surges on low rpms while throttle is half closed. So its really taking out the opposing force out of the comp wheel.

The exducer or the bottom blades throws air out so that leaves more access area.

Thats all theory, and every one believes in different things. So I'm testing it out.

would a bov (plumb back) that leaks at idle/low throttle basically perform the same thing?

That only acts after the throttle is shut. The surge slots releases surge while accelerating.

Ie. exhaust wheel still spins while I’m half throttle, how ever the open on my throttle body does not create enough volume to swallow all that boost. So some bounces back, creating this Tu tu tu sound. I've seen quite few people mentioning that in the force induction section. But how much pressure exist while throttle is fully opened, If so, having the slots would show a increase in response.

Oh I meant similar to how the stock bovs operate, how they leak on idle and very low load, if you could tweak it so they leaked on slightly higher load (10% throttle) to give a feedback effect similar to the anti surge slots, this way you could tune it to suit so that you dont waste too much energy with air recirculating, but also achieve the anti surge effect.

Oh I meant similar to how the stock bovs operate, how they leak on idle and very low load, if you could tweak it so they leaked on slightly higher load (10% throttle) to give a feedback effect similar to the anti surge slots, this way you could tune it to suit so that you dont waste too much energy with air recirculating, but also achieve the anti surge effect.

It certainly feels like the case, I guess Nissan did put in lots of thinking in their design.

Also it leads me to think if the upper blades do any thing if the anti surge slots are set in between. I might just machine them all flat which leaves more induction area. Also I don't remember seeing any anti surge slots in the new machined wheeled turbos that Garrett is bringing out, apparently they don't run the lower blades.

Oh I meant similar to how the stock bovs operate, how they leak on idle and very low load, if you could tweak it so they leaked on slightly higher load (10% throttle) to give a feedback effect similar to the anti surge slots, this way you could tune it to suit so that you dont waste too much energy with air recirculating, but also achieve the anti surge effect.

The stock Stagea bov has a 4mm hole which seems to bypass all the time, I filled the hole with a grub screw and it surged badly, only at part throttle, and the whole car surged in time with the noise, I removed it and noticed the part throttle surge gone and bov response back to normal. This will be part of why I cant hold 20psi though. Perhaps a solenoid bypassing when the throttle is at less than 50% is the go?

The stock turbo has a surge groove but no port, I had that machined out with the highflow.

I havent seen the stock RB valves close up, I didnt realise they were different.

Photos of the bearings before installation:

bearings.JPG

Turbo's installed.

oncar2.JPG

Regarding to those anti surge holes, I think the best description would be driving with a massive air leak. Or unless I am driving with a massive air leak. They do make heaps of noises. I'll going to machine another housing without surge holes for comparison.

Technically you should just do testing on the "abe" spec atr43g3 without the surge holes so you can compare the journal bearing to the twin ceramics as a direct comparison...

If you are also adding anti-surge slots as well you are adding another variable and can't show true results!

After you compare the bearing types, then move onto anti surge slots :laugh:

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