Boost Restrictor Removal Opinions R33 Gtr

[livewire]

Ok, i know there are a few posts regarding this and its quite an old topic but through research it seems opinion is quite divided and a few comments on another post of mine have added to my curiosity. Im just wondering if i can get a few definitive answers as these cars are quite old now so some people would have had a lot of experience with them over the years now.

Ok so, as most people know, the famous brass boost restrictor inside the hose marked with the yellow band when removed apparently increases the factory boost to 1bar. Now while a lot of people have the opinion that 1bar is not safe at all others say its perfectly safe and after a comment that i have come across on other forums around the world even that the boost restrictor was placed in the hose to keep the cars horsepower output under its actual tuned potential under the 'Japanese gentlemans agreement' at the time and that the car was actually always intended to run 1bar and that the hose housing the restrictor was marked with a yellow band for the ease of locating it for removal after purchase.

Can anyone confirm whether this is the case or not? As i know they do run quite rich from factory which makes me think this is one possible reason?

Also, cars fitted with the 'nismo sports resetting' ecu's apparently increased boost to 1bar along with removal of the speed limiter. Now if this is the case, one would presume running 1bar of boost would be quite safe being a nismo option or were these ecu's maybe tuned richer again to counter the boost increase?

Would be good to get more clarification on this.

Thanks guys

Any

Also, apparentlecusports resetting

Edited June 9, 2014 by livewire

[niZmO_Man]

What? Just remove the restricter, standard ECU handles it fine (I get 0.9bar).

[XGTRX]

Will be fine.. it is a closed loop system, the AFMs and O2 sensor should manage your mixture fine. Don't worry about it. 1 bar will not push your tune to the limit.

[livewire]

Yeah, i have no doubt the ecu will handle 1bar no problem. Im trying to get more info on the truth to the comments about the boost restrictors being placed there to decrease the power output as per the gentlemans agreement and that the gtr was infact designed to run 1bar without turbo reliability issues like a lot of people seem to think removing it causes. More than just a handful of people strongly suggest against it where some have said nismo even reset some ecu's from factory as an option i presume to run 1bar so im just trying to get clarification if anyone has a definite answer as im probably not the only one who has wondered

[Ben C34]

Yeah, i have no doubt the ecu will handle 1bar no problem. Im trying to get more info on the truth to the comments about the boost restrictors being placed there to decrease the power output as per the gentlemans agreement and that the gtr was infact designed to run 1bar without turbo reliability issues like a lot of people seem to think removing it causes. More than just a handful of people strongly suggest against it where some have said nismo even reset some ecu's from factory as an option i presume to run 1bar so im just trying to get clarification if anyone has a definite answer as im probably not the only one who has wondered

You have answered your own question.

The fact the ecu doesn't spaz out and cut the fun when the restrictions are removed goes to show nissan are cool with you pulling them out.

If they didn't want to be able to run high boost they would have had the ecu cut when it senses too much airflow.

As for whether your old turbos can handle it,that's another story.

[livewire]

Well no i haven't answered my question because my main questions were whether anyone can confirm whether other peoples comments I've read are correct in regards to whether they were designed and tuned to run 1bar, whether the boost restrictor was only fitted to decrease the power output from factory etc and whether that answers the question of whether the factory turbos can safely run that boost because im sure Nissan would have been quite aware of the factory turbo limits but a lot of people say no so just trying to find out whether its just a myth or not.

I never once asked whether the factory ecu can handle it or not,

[Ben C34]

Ok

I will say iy again.

The ecu runs the car correctly at 1 bar.

If nissan didn't want that they would have made it dump in heaps of fuel and pull timing like they do on other ecu's when the boost is raised.

[scotty nm35]

I have seen factory 34 turbos run 300kw on 98, and 32 N1's up over 400kw in a Gibson race car. They are nowhere near their limits at 1 bar. The hassle is they are old, making the ceramic brittle. They would be fine if they had been changed at the 100,000k service like the Stagea service schedule stipulates.

[Ben C34]

Option one.

Ring nissan and ask them them for confirmation.

Option Two.

Pull restrictors and boost off into sunset like countless others before you. (Forever wondering if turbos will go bang)

Option three.

Open wallet. New turbos.

Boost off into sunset.

[iruvyouskyrine]

You are all missing the point.

Dear OP.

No one on this forum (as far as I am aware) worked for Nissan in Japan between ~1986-2003 so therefore cannot give you an absolute clarification on whether or not the restrictor was put in so that GT-R's would adhere to the 'gentlemens agreement'

What everyone else IS saying is that there are many logical conclusions all pointing to the fact that, yes, GT-R'a came from the factory at quite a bit less than their potential allowed for. This gives reason to believe that yes the restrictor was indeed put it place to keep the GT-R's tamer and not break the agreement. While attempting to adhere to the agreement though, I would not say it was the sole reason for limiting the cars output, there would have been many other factors influencing that particular decision.

So, once again. Nobody on this forums can answer your question in absolute terms. Although the answer is almost certainly yes.

[livewire]

Let me try ask it more simply.

Does anyone know whether the rumour is true that Nissan only fitted the boost restrictor to reduce horsepower as per the 'gentlemans agreement' power rating? And was designed and intended to run without it in place which is why the hose was marked with a yellow ring to make it easy to locate and remove?

I dont mean to sound like a prick but im not asking whether i should do it, im going to do it or looking to boost off into the sunset wondering if turbos will go bang. Im not asking whether the ecu is capable of running more boost etc, i just want to know whether the stories I've read about the boost restrictor have any truth to them, that's all.

Edited June 9, 2014 by livewire

[livewire]

Ok thanks iruvyouskyrine, that is the best response so far to what im actually asking.

Im just curious as to whether someone maybe has researched it more, maybe since 1989 has had confirmation from someone who does know or whether its nothing more than a presumption.

[XGTRX]

I would say these type of opinions are based on 20 odd years of research so just take them as gospel.

[djvoodoo]

OP your avatar mentions you have an R34 GTR.

For what it's worth.

I have been running my 34R with original turbos (car has done 116,000km) at 1.1 bar (restrictor removed, full exhaust and Power FC) for the past year with no problems. I put 5L of oil in each service, and 5 L of oil comes out. No smoke, no loss of anything!

Will be putting on -7 (34 N1's) next month, so will report back on the condition of the turbos once I get the car back

[livewire]

I did own an R34 gtr and my 34 was running pretty much an identical setup to yours and same boost with no issues as i was told the R34 turbos could actually handle more boost despite still being ceramic. I had stock turbos, 720cc injectors, walbro pump, power fc, profec b boost controller, 3" front pipe back exhaust and the car was great fun and tuner said that boost on factory turbos was fine. Never had an issue anyway. -7's should add even more fun for you :-)

Im currently in the process of getting an r33 gtr so just doing some research on its limits etc

Edited June 10, 2014 by livewire

[GD51LA]

I pulled the restrict or out, and got it tuned, the tuner said it was ok, it showed no boost spike on the dyno

Drove the car at night, suddenly get boost spike every time I put my foot down, it started pingining (allot)

Then again, my mate did the same thing in his 33gtr, it's been running fine for two years, using factory ecu (then again he doe sent really drive it hard)

I suggest using a proper boost controller