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How Much Power From Stock R33 Gtr Ecu?

Don Dada

By Don Dada,
in Engines & Forced Induction

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Don Dada Mentor

Don Dada

Posted
Posted

Ok guys, have a few questions about the stock R33 Rb26 ecu....

Firstly i have read that the Rb25det ecu has a "low octane map" it uses when the fuel is not up to scratch to protect itself in addition to the R&R feature when the ecu senses too much air flow, also some kind of violent cut which some refer to as a boost cut and others a fuel cut.

I have experienced these features on my 25 when boost is raised too high for the ecu liking.... but what protection does the stock 26 ecu offer?

The reason i ask is that there is only 95 available here, and using a safc2 just to determine knock, i was able to get increasing levels with increased boost(as low as 12psi), and as the temp became hotter.

Does this mean the stock ecu does not have a "low octane map"? because i could have trashed the 25 under the same conditions and get no knock!

The 26 ecu however have pulled timing on me once, but that was when i think i adv the ign timing waay too much(fu#&ed up timing light)

I will be changing the turbos to a set of -9 (GT-SS) soon and really don't have the paper to fork out for a pfc at the same time, so i was thinking of running the stock ecu and may be some water/meth since the stock ecu is designed to work on 100ron anyway the water/meth should be able to get me there.

So on that note , how will i know when the ecu has reached its limits?? I was thinking mostly of maxed air flow voltage??? which at this stage u should get some sort of cut?... or may be maxed inj duty cycle?

I know it will not be the optimum set up, but i think i could get away with it by maybe tweaking the fuel pressure a little and using the water/meth.

What do u guys think???

I know R31Nismoid and a couple other guys upgraded turbos and ran the stock ecu..... your input pls :P

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

250rwkw @ 13psi with GT-SS's :P

Didn't drive as nicely as a PowerFC tune for the setup, but was pretty good overall

But its all subjective, your running lower octane fuels with meth injection, so its really going to be a suck it and see kinda thing really.

The stock ECU is not as nasty as a RB25 one that's for sure. If you start playing wih fuel pressures then you are also bringing in another element so you really just have to get it on the dyno and carefully observe what is going on.

Don Dada Mentor

Don Dada

Posted
  • Author
Posted

Ok

I'm making 246rwkw now on Dyno Jet @14psi stock turbos, 3"exh, apexi pods with cai and the car pulls really smooth,although a little lean in the midrange since i installed the apexi pods with cai which i feel is contributing to knock, so i am interested to see the results with the water/meth and probably a little more boost than you were running.

paulr33 Grand Master

paulr33

Posted
Posted

i think youll find the stock ecu a limit once you add any reasonable level of power

everything aftere that is going to be comprimise for the tuner and what the ECU can phsyically support

ie with piggybacks and add-ons like the SITC and SAFC and extra injector controllers etc its all going to be a comprimise

there would come a point where whatever solution you had would cap at a given injector size etc

tuning a powerfc or other stand alone ecu's is exactly mega complex vs the stock ecu (remapping it)

so if you can find someone to remap a stock ecu, with some training and documentation they could learn PFC or other ecu's

all the same basic fundamentals of EFI tuning apply, its just the interface is a bit different in each, and how it looks, plus add-ons

they all have an AFM or MAF or MAP, a load axis, an RPM axis, variious standard sensors and correction etc

STATUS Grand Master

STATUS

Posted
Posted
i think youll find the stock ecu a limit once you add any reasonable level of power

everything aftere that is going to be comprimise for the tuner and what the ECU can phsyically support

ie with piggybacks and add-ons like the SITC and SAFC and extra injector controllers etc its all going to be a comprimise

there would come a point where whatever solution you had would cap at a given injector size etc

tuning a powerfc or other stand alone ecu's is exactly mega complex vs the stock ecu (remapping it)

so if you can find someone to remap a stock ecu, with some training and documentation they could learn PFC or other ecu's

all the same basic fundamentals of EFI tuning apply, its just the interface is a bit different in each, and how it looks, plus add-ons

they all have an AFM or MAF or MAP, a load axis, an RPM axis, variious standard sensors and correction etc

actually pfc's are among the easiest ecu's to tune, a remap is far more complex..

Don Dada Mentor

Don Dada

Posted
  • Author
Posted
slap in a r32 ecu and the AFM's become the limit, i have two 26's making high 300's on remaped r32 GTR ecu's.

The O2 sensors are probably the only difference between the R32 and R33 right???

In that case if i were to use a R32 ecu on the R33, will it recognize the O2 sensors and function properly in closed loop?

STATUS Grand Master

STATUS

Posted
Posted
The O2 sensors are probably the only difference between the R32 and R33 right???

In that case if i were to use a R32 ecu on the R33, will it recognize the O2 sensors and function properly in closed loop?

i did another one yesterday pretty much stock GTR with catback. It was a late model R33 Vspec and i gaurantee all the sensors etc work spot on including 02 sensors.

Brandon Veteran

Brandon

Posted
Posted

Something else I found when looking at HKS dumps.

After market dumps like HKS or Tomei has the same part number for 32/33 and in some cases (HKS) 34 as well. The only difference between 32/33 and 34 is the extra O2 sensor which is specific to 34 vspec (according to HKS, called supplier up) but Tomei for some reason have the same part number for 34 and 34vspec. They should just be bolt on mods in anycase.

Don Dada Mentor

Don Dada

Posted
  • Author
Posted
i did another one yesterday pretty much stock GTR with catback. It was a late model R33 Vspec and i gaurantee all the sensors etc work spot on including 02 sensors.

Just curious...What full load timing u guys run on a stockish gtr running about 14psi??

STATUS Grand Master

STATUS

Posted
Posted
Something else I found when looking at HKS dumps.

After market dumps like HKS or Tomei has the same part number for 32/33 and in some cases (HKS) 34 as well. The only difference between 32/33 and 34 is the extra O2 sensor which is specific to 34 vspec (according to HKS, called supplier up) but Tomei for some reason have the same part number for 34 and 34vspec. They should just be bolt on mods in anycase.

the ecu is only looking for a voltage so sensor type/size is not an issue when swapping out the r33 for the r32.

STATUS Grand Master

STATUS

Posted
Posted
Just curious...What full load timing u guys run on a stockish gtr running about 14psi??

i limited the boost to around 12psi on the v-spec as it still had stock front pipe filter etc, timing was around 24-26 degree mark at 8000.

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