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I've got a catco 3 inch cat, heading back to the tuner in a couple of weeks to get a retune with the cat now being single cell. So should give some insight into what type of restriction they cause, I have done a few other things though, so wont be an entirely accurate back to back from cat, to no cat.

Have changed to a apexi front mount kit (non return flow type), added splitfires, new fuel pump, and "high flow" cat.

Should be interesting to see what the OP6 highflow can do on my RB20 with these extra mods, previously was 240rwkw, will post results, tune is booked for 29th.

Other thing worth mentioning is the Ball bearing cartridges works extremely well with the new SAT turbine including the current ATR45SAT, G3, SS2 and OP6 high flows.

That have made a very noticeable difference to throttle response making the car feels much "lighter" on and off throttle. Highly recommended for street driving machines.

Needs to be 100 cell 5 inches cat, no cat with exhaust Tee will give you the best result.

5" cat is HUGE! Are you recommending a full 5" system Stao? or step down from 5" cat to 3.5 or whatever?

Other thing worth mentioning is the Ball bearing cartridges works extremely well with the new SAT turbine including the current ATR45SAT, G3, SS2 and OP6 high flows.

That have made a very noticeable difference to throttle response making the car feels much "lighter" on and off throttle. Highly recommended for street driving machines.

Was this included in my turbo Stao? Or did I miss out on this?

Cheers

ATR43's BB cartridges has been out for a while now. Except it didn't make much of a differences working with the older turbine end. Using the new SAT turbine there is a noticeable improvement on drive ability.

Turbine side looks like:

rear.JPG

Ok I see. 21u high flow sounds super responsive.

Re. The cat - I'm already getting the exhaust shop to make a few mods to the trust system I'm putting on. I was thinking of getting them to put some flanges on the below.

Anyone got a view on them - only mild steel but don't think it would cause too much issue.

http://www.ebay.com.au/ulk/itm/151798759239

Edited by benl1981
  • 2 weeks later...

Can't be lowered?

Depending on how free flow every thing are. If you have a cheap cooler with an 3 inches turbo back it will be running at lower boost. Far as engineering concern, this turbo is made to hold upper rev boost and getting close to 300rwkws as possible internally gated.

Yes it is. But we don't BB 21U high flows. They are already so responsive to a point any better will cause the turbo to surge.

Seems a backwards comment. Wouldn't you be better off slightly increasing flow then gaining response back with CBB. You would have more power with the same response, and better transient response.

For evaluations, I usually stick CBB catridges into turbos with tinny housings and run high boost, trial its reliability under extreme heat and back pressure. That 287rwkws run is with Ceramic ball bearings. it starting to surge light throttle in 3rd and 4th unless WOT, very loud on dyno. 20psi by 3500RPM 4th gear manual on a RB25det is about where the surging point is.

Because the 21U is so small, I couldn't feel any differences in down low throttle response.

Something interesting I found out today - Put a pod on my car for all the choo choo sounds (not really) but it makes more boost easier in all gears... 1.10 pound in second easily and full boost in third easily.

I had the stock airbox on but I put the pod on with the factory snorkel for cold air feed.

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