Supporting upgrades needed for turbo swap RB26DETT

Hello everyone,

I have a R32 GT-R that is nearly stock, the only differences from stock when it come to the engine operation is a free exhaust and blitz 'cold' air intake cones. The current power output should be slightly more than stock but nothing too far from it.

Recently one of the stock turbo died, the wheel on the exhaust side was neatly cut off from the axle and gone on the highway through the free exhaust. I think this is age and heat cycles on a ceramic wheel that is likely the cause. Anyway I wanted from some time now to swap the stock turbo because they were known to break and prevent what happened to me. Also my goal in term of power output in the futur would be around 450/500 HP, but right now I just want to be able to drive the car again safely while laying the fundation of the final build.

I'm undecisive for the turbo choice :

- GT2860R : one of the cheapest choice and known to be a solid option for the RB26 twin turbo setup, great for response, close to stock even though the wheel isn't ceramic anymore.

- GT2860RS : same price as before, also a known choice for the same setup, the max power output is greater but you sacrifice a little of response time.

- GTX2860R Gen2 : The modern equivalent that theoratically surpasses the previous choices, hard to find a set for the right price and it could need a lot of supporting mods to be able to drive the car again.

I'm not considering HKS twin kits, way too pricy for me. And i would like to stay with Garett for the turbos as it was stock.

Also, I want to stay with a low mount twin setup as stock, here in France car modification is.. let's say shunned.. and so I prefer the car to look like stock as much as possible, and I like to keep the essence of the car as it was stock, just with more vitamins.

I would like to know, which one of those turbos set you would favor for my objectives ?

Aside from the turbo choice, I came here to discuss about the needed supporting mods I should install when swapping turbos with those options.

1 - Standalone ECU

With the turbos swap, the fuel and ignition maps should be revisited, and the car tuned to check for knock/detonation.

I could limit the boost pressure to be below the fuel delivery system and MAF Sensors limits, the MAF sensors should still be able to get the mass of air entering the engine and so the ECU would know how to inject fuel to get the mixture to target lambda. Or do I miss something ?

However, I would still install a standalone ECU, namely the new Haltech Nexus plug&play for the R3X GTR with a wideband sensor, so I could remap if needed, set engine protection mecanisms and I could probably need it for the boost control for the new turbos, replacing the stock system.

2 - MAP + IAT Sensors

Again, if i'm not wrong I could limit the boost pressure to be below the MAF sensors max threshold. However I could swap for MAP + IAT sensors and map with MAP+TPS because of the ITB on the RB26 to be more secure and avoid lean mixture.

I believe I already have a MAP sensor on the intake inlet, there is a reading for boost pressure on the dashboard, I could add a 'T' to provide this input for the ECU ?

And for the IAT I think the best would be to modify the piping before the intake inlet.

I do believe there is experienced tuners and enthusiasts here that could provide me the right insights to make my vision clearer ! :)

Hi.

For your power goal I would choose gtx2860 by Pulsar turbo. Those are excellent quality turbos for half a price of Garret. We just ran our JZ engine with Pulsar turbo with 7.8ET. Also Jay from ex Real Street Performance was saying all good stuff about these turbos in his last interview. Each GTX2860 is good up to 300hp on pump gas and would still have reasonable spool response.

As far as ECU goes I think you need to find a reputable tuner in your area first and then go from there. It would be wise to discuss your thoughts with him and see how he suggests to go about it. I don't think you want to buy an aftermarket ECU and find out there is nobody to tune it for you so you will have to start looking for people to tune it remotely and it doesn't always work out in good way...

I redid all my calculations for the turbo choice, I'll go with the GT2860R-7, it would be at the same price than the pulsar GTX delivered at my address, and I want to have the best response as possible. For my power goal I will land in the most efficient part of the compression map without getting into surge.

For the ECU the haltech elite and nexus are widespread here in France for the RB in general, I will tune myself hand to hand with an experienced local tuner with a dyno.

I'm still looking for the needed supporting mods, first the MAF, injector, fuel rail, fuel pump limitation in term of power. But also about oil/water and anything to support safely the new power output (between 350 HP and 500 HP, first I focus on safely driving the car with workings turbos).