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Once the actuator bracket has been played with please make sure the actuator is preloaded. have a look at this video footage.

(ignore the sound as the camera was held my mouth lol)

It should have a 14psi actuator on there. Make sure the car has a free flow exhaust with a 4inch induction pipe and a free flow pod. Any restrictions in the cooler, intake and exhaust will cause boost drop.

Also check the idle timing with a light gun, make sure they match 15 degrees or what ever your ecu tell you before taking it off for tuning. Have seen few customers cars with few degrees out after cam belt change.

I adjusted the preload, had the hole half covering the pin then pulled the rod out and put it in place. Do I need to give more preload than that? I cant really tell how far back you have the actuator arm from the video.

Exhaust and intake should all be fine, I have a 4" metal intake, good cooler and 3" turbo back with a good cat.

My timing shows about 30 degrees with a light however. Has since I bought the car and I haven't changed it because it runs perfectly.

Edited by Daza33

Normally is half a whole, you can pull back more.

The cat needs to be in 100 cell with straight through mufflers. Also note some dump/front pipes don't match up with the inside part of OEM gasket that needs dressing up. see how it goes on dyno first, would prefer to try a run with cat dropped off.

The idle timing must be refer to user manual, 15 degrees @ 650 RPM, adjust it through the CAS. Or it won't take timing and pins when comes to boost.

Ok well I gave it about 5-6mm preload, still the same 10-11psi. I have a JJR bellmouth dump which I cleaned up with a die grinder and matched to the gasket.

Not running any mufflers, I'll adjust base timing tomorrow at work and see how it goes.

I'll throw my boost controller on tomorrow and see how much boost I can gain out of it.

The actuator on there is a 14psi low pressure actuator, I found many tuners don't like start tuning from 18psi, Pressure drop varies between setups, but a boost controller will definitely rise boost. I do have 18psi high pressure actuators, which you can buy and send back the one you don't need for a refund of the actuator.

Yeah thats what i figured, just found it a bit odd as with the stock turbo I was getting 10psi as well, and from my knowledge that is a 5psi actuator. Either way, as long as my controller gets it up to the 17psi sort of mark I'll be happy.

Can't wait to get it to Toshi for a tune, it pulls pretty hard on 10psi with the stock ecu so I can only imagine what it will be like with a tune.

Can't wait to get it to Toshi for a tune, it pulls pretty hard on 10psi with the stock ecu so I can only imagine what it will be like with a tune.

That's if the engine doesn't blow up before taking it to toshi. Keep it off boost til its tuned or your wallet might be very empty

That's if the engine doesn't blow up before taking it to toshi. Keep it off boost til its tuned or your wallet might be very empty

What I don't understand about this way of thinking is that if he's still running the stock ECU, then he's still running a stock AFM. How can it damage the engine if it still has R&R? Being a bigger turbo, it will come on later than stock anyway so don't have to worry about it hitting cells it isn't tuned for....so other than that, AFM measures airflow which means it shouldn't manage to lean out at all.

Running a MAP sensor and going to a larger turbo without a retune is a completely different story though.

Yeah I know all this, still running the stock AFM at the moment but have a z32 and s15 injectors waiting to be dropped in. Not thrashing the shit out of it, just gave a couple runs to see how laggy the turbo is compared to stock. And yes, it does hit R&R.

What I don't understand about this way of thinking is that if he's still running the stock ECU, then he's still running a stock AFM. How can it damage the engine if it still has R&R? Being a bigger turbo, it will come on later than stock anyway so don't have to worry about it hitting cells it isn't tuned for....so other than that, AFM measures airflow which means it shouldn't manage to lean out at all.

Running a MAP sensor and going to a larger turbo without a retune is a completely different story though.

The ECU goes to R&R based on a few basic inputs. AFM voltage, TPS, RPM. If the balance of those doesnt add up the ECU will flick into R&R.

1. That doesnt mean the ECU will go into R&R at all, as the R&R is programmed around parameters for the stock turbo. Areas of the map that just dont add up with the new turbo.

2. Theres nothing to stop it knocking before R&R. Again its basing its tune state on those simple parameters so it will be accessing areas of the map which are entirely irrelevant to what its really doing.

long story short, it has the ability to lunch the motor very quickly.

IF it registers on that part of the map. its a digital box basing its map position on inputs, inputs that are irrelevant once you change the fundamentals that create those parameters.

Each to their own. If you think its safe, go for it. Otherwise, avoid becoming SAU's flame flavour of the month.

I mean its not like there aren't threads on here already which prove it does f**k the motor or anything... Of course not...

I think you think I'm defending the practice. I'm not. What I'm actually telling you though is that the high load high rev parts of the standard shitty RB25DET maps are really rich and really retarded. If you go there, it will not lean out. If you instead manage to get to really high loads without the revs also being high, then you are a candidate for triggering real R&R, which should also be safe.

I would like you to put your thinking cap on and describe some real, indisputable scenarios where you could detonation causing conditions on a standard RB25DET ECU with a bigger turbo. Consider it a thought experiment.

Exactly as I was thinking....I thought the standard maps were only 2D - RPM and load, with load being defined as airflow

(disclaimer: this is COMPLETELY assumption, I actually have no idea and have never seen stock maps).

I have a mate who ran -5's turbos on his freshly built 32R for about 4 years on a stock ECU.

he gave it a pretty good thrashing too. Car still run well to this day, finally got a tune.

Racepace did a before run on the dyno and made 260rwkw

Some further updates, for the billet SS1 and SS1.5 .

The current SS1 runs a 71mm cast comp wheel, the newer version will be running a 60mm billet wheel with blade edge extension, smaller hub longer and cropped blade profile. This 60mm wheel should have the equivalent output as the current 71mm cast wheel with lot less in weight. Targetting is around the 240rwkws mark on 98 with excellent response. This wheel is ideal for people with Rb20det and SR20det engines.

60mm.jpg

60mm2.jpg

This is the SS1.5, the current 71mm compressor on the SS2 is rated to about 500HP, this 64mm wheel in theory should provide around the 470HP mark. I've packed large blades with extended tip on this wheel using a small 12mm center hub. Final goal would be 20psi by 3000RPMs using the SS1PU turbine while making towards the 270rwkws margin with very sharp throttle response.

64mm.JPG

64mm2.jpg

I think you think I'm defending the practice. I'm not. What I'm actually telling you though is that the high load high rev parts of the standard shitty RB25DET maps are really rich and really retarded. If you go there, it will not lean out. If you instead manage to get to really high loads without the revs also being high, then you are a candidate for triggering real R&R, which should also be safe. I would like you to put your thinking cap on and describe some real, indisputable scenarios where you could detonation causing conditions on a standard RB25DET ECU with a bigger turbo. Consider it a thought experiment.

Realistically neither of us can say what will happen, were both just guessing. Assumptions based on an understanding of how the system works.

You seem to think theres little that can go wrong as the high load areas are R&R enough to soak up most of whats going on.

I think that the change in exhaust restriction (bigger turbine and housing) coupled with the change in compressor efficiency (flow from the wheel aero iteself and difference in housing AR) can result in the ECU reading areas of the map which are irrelevant to what its actually doing. Running at an AFR and ignition combo with will start to see signs of det relatively easily. I think it is far more complex than high load or low load, otherwise we would not waste money on expensive tunes.

In my own case Ive had my car tuned OKish rich but with very little timing and it would ping its guts out the moment something wasnt 110%. Have also changed an exhast cam for a slightly larger item (both oem) and completely lost the tune. That tells me the sweet spot for a tune isnt 'thereabouts' in all cases and these things can be pretty sensitive. something I would prefer to advise people against.

Not to say Ive never put a T28 on a CA18 and thrashed its guts out as is for years.... But its just not the advice I would like to give, given my other experiences and understanding of how the thing works.

Hmm... billet goodness, Stao will that new compressor wheel fit into a stock RB20 housing?

Yes I can make it fit into stock Rb20 turbo housings and use as high flow.

Stao is that SS1.5 billet wheel different to my SS1PU wheel?

Yes, It is smaller in diameter with different wheel blade and hub configuration. It should have a strong none linear pull behavior similar to a K04 in the VW GTRs.

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