Bigger turbo on stock ECU?

[ToroGTS]

Has anyone run a turbo larger than the RB25 (or neo) on the stock ECU with relative success? I'm thinking of going to about a 0.63 A/R unit and I'm hoping that I could get away with just a SAFC, Wideband and playing with dropping the timing a couple degrees.

[garetth]

Running the stock ecu with a bigger turbo will not get you very far, An a apexi safc just tricks the maf into reading more or less air and is generally looked down upon. If you want to get a bigger turbo look into nistune it will only be $200-300 more then a safc.

[specialedition]

nistune where can i buy?

[nick-nismo]

You can buy nistune from their website. It's 270$. Easily the cheapest and best option other than full stand alone

[ToroGTS]

I'm not looking to make maximum power at the moment. More so looking to maintain the safety of the engine. Ultimately I will be doing the RB25 swap so this RB20 is kind of just a stepping stone. Still wondering if anyone has first hand experience running the OEM ecu with more than the basic mods.

[blackdeath]

i got my car with front intercooler upgrade t28 ran like poop on stock ecu . till my nistune

[ToroGTS]

T28 is quite a bit larger than stock, larger than I was thinking of trying. How was spool up on that though. I'm looking at a similar hot side.

[Skym]

With stock fuelmap, stock fuel system it will make engine run leaner at lower rpm (as high as 13.5:1 A/F with hybrid RB20 turbo, podfilter, 3" exhaust from dumppipe, BOV mods) and throughout powerband. But is very responsive (increased transient response). FMIC should make boost level rise 1.5psi or so, but that would result in a very lean A/F ratio (not recommended).

Fitting a bigger lph fuelpump (hard wired to get higher voltage to fuelpump) with stock FPR should put it into 10's (even with FMIC) with A/F ratio at mid to high rpm where injectors are open more.

[yanay]

I am running a rb25det s2 with a precision 5252e turbo external wastegate on factory manifold tune with just a wideband, bigger fuel pump fmic and adjustable fpr. I have it running about 7 psi and my wideband numbers are all still quite safe (setup has been on for about 6 months 20,000 kms). Never had a issue from this bigger turbo.. I even called autodream (local shop) one of the techs said he has been running a gt35 on his rb25 un tuned for years at 12psi.

[ToroGTS]

Seems like I should be safe. I'm looking at running a .63AR hot side with 0.5 cold side (Stock RB is 0.5 hot, 0.5 cold), compressor wheel/intake only ever so slightly bigger, on a higher flowing manifold and downpipe. Right now running stock RB20 turbo at 12-14 psi on a Walbro, Mines ECU, FMIC, HKS mushroom, stock FPR, LS2 coils and it is running so RICH I'm getting about 100 km on 20 L gas and throwing fireballs out the exhaust. Mileage went in half with the addition of the walbro. I'm actually thinking that extra air will do me big favours in this equation.

[Skym]

Running rich should make it feel sluggish and with running too rich you have to worry about washing the bores of oil.

Flames from exhaust can mean o2 sensor is fouled (due to engine running rich). Basically o2 sensor is slower to react, so makes ECU make engine run rich longer.

A stock ECU retune with Nistune, new o2 sensor should help to get rid of the running rich problem. There can be from 15hp (safe tune) to 30hp (aggressive tune) hiding away.

[ToroGTS]

My o2 sensor is brand new with very little mileage since the new fuel pump. I'm going to get the turbo on there with a wideband and see how she reads, then consider my management options from that point. My biggest concern is that the mines tune I have currently has the timing advanced with increased rpm, although it claims to be tuned for higher boost which I would assume means less advance with boost increase. I need to get my car on the consult software again and see what the timing map looks like. I recall it was in the realm of -27 btdc at WOT higher rpm... I would likely just back off my base timing at the CAS if I started getting crazy knock reading after all the upgrades I make in spring.... ohhhh custom engine tuning....