# Removing restrictor at boost valve



## MS33 (Jun 27, 2007)

I believe removing the restrictor will increase the boost pressure from .75 to 1 bar, does this make a big difference to performance?

Is this increase ok if you still have the stock turbos, being there ceramic internals? 

More curious than anything, but thought I'd better get the low down.

Also what's involved in a stage 1 mod?


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## LozGT (Dec 8, 2005)

Hi there. Yes removing the brass restrictor does appear to result in an increase of boost to one bar. You will notice a difference in the performance but I would be wary of increasing boost to 1 bar on the stock turbos. There are as many stories of people running 1 bar without issue as there are stories of those whose standard turbos have failed following an increase to 1 bar. Just to be on the safe side I'd keep boost to less than one bar with the standard turbos. Also, I'd be mindful of fueling/timing parameters following any adjustment to boost settings.

As for a ‘stage one mod’, it seems to come in the guise of bolt on items to modify intake, exhaust and engine running parameters (ECU changes for instance) and may involve adjustment to boost settings to gain the benefits of the enhancements. That’s my understanding anyhow. I may be wrong…..


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## JapFreak786 (Aug 29, 2003)

how'd you remove it guys? i've got 2510's on mine wouldn't mind some more boost


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## GOGS 2 (Jun 21, 2009)

i noticed a big difference when i removed the boost restrictor. when i first got my r32 gtr it felt slower than my old e36 m3. untill i removed the boost restrictor a healthy gtr should make about 350hp with the boost restrictor removed


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## MS33 (Jun 27, 2007)

Thanks lozGT, most appriciated.


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## MS33 (Jun 27, 2007)

Thanks guys, didn't relize I'd had more replys


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## MS33 (Jun 27, 2007)

Japfreak, if you look at the offside suspension turret, you'll see the boost valve with two pipes coming from it, one has a yellow ring around it, if you feel there, you'll feel the restrictor inside.


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## DrGtr (Jul 18, 2009)

LozGT said:


> Hi there. Yes removing the brass restrictor does appear to result in an increase of boost to one bar. You will notice a difference in the performance but I would be wary of increasing boost to 1 bar on the stock turbos. There are as many stories of people running 1 bar without issue as there are stories of those whose standard turbos have failed following an increase to 1 bar. Just to be on the safe side I'd keep boost to less than one bar with the standard turbos. Also, I'd be mindful of fueling/timing parameters following any adjustment to boost settings.
> 
> As for a ‘stage one mod’, it seems to come in the guise of bolt on items to modify intake, exhaust and engine running parameters (ECU changes for instance) and may involve adjustment to boost settings to gain the benefits of the enhancements. That’s my understanding anyhow. I may be wrong…..


Is nothing wrong with the ceramics at 1bar all r34 ukspec are 1bar and running ok. Does anyone know if the uk spec have the restrictors? i have never check


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## MS33 (Jun 27, 2007)

I've read since posting this thread that some people recommend not removing the restrictor but drilling it out to about 3mm in dia.

What are your thoughts?


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## miragev (Apr 11, 2007)

as i understand it nissan placed the restrictor there only to comply with the 280 hp gentlemans aggrement and they placed it in the boost pipe with a yellow ring so the car owners would know where it is so it could be removed easily ...! go for it i removed mine straight away with no problems and you will notice a difference 
alot of gtrs now are fitted with none standard turbos in any case did you check to see if yours have been changed ?


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## MS33 (Jun 27, 2007)

Thanks miragev, I haven't checked, more because of the hastle of doing so, do you still have the ceramic internal turbo's?


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## typerchris (May 8, 2007)

just remove it that is what most people do including me. Was fine even before it was mapped.


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## Pete G (Aug 18, 2008)

MS33 said:


> I've read since posting this thread that some people recommend not removing the restrictor but drilling it out to about 3mm in dia.
> 
> What are your thoughts?


I did that to mine and noticed the difference straight away,- then I took it out and it felt like it had a bit more


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## MS33 (Jun 27, 2007)

Pete G, are you still running the ceramic turbos? And how long for?

Just a bit apprehensive!!

Mike


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## miragev (Apr 11, 2007)

MS33 said:


> Thanks miragev, I haven't checked, more because of the hastle of doing so, do you still have the ceramic internal turbo's?


i was running standard turbos before with the restrictor removed with no problems i'm running 2530's now
mate thats whats it's there for to be removed thats why nissan made it so easy to do get on with it ...


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## MS33 (Jun 27, 2007)

Thanks miragev, I've removed the restrictor and will give it a run later.

Will let you all know how I got on...fingers crossed!!! :thumbsup:


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## nightcrawler (May 7, 2010)

ive got an r32 stock without a boost controller. if i remove the restrictor (which will give you boost up to 1bar) do i still need a boost controller?

i dont have any plans of going above 1bar but i feel my previous impreza is more faster than my gtr =(

how do i remove this literally?any pics of the restrictor?

sorry i might be ignorant on this


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## Pete G (Aug 18, 2008)

MS33 said:


> Pete G, are you still running the ceramic turbos? And how long for?
> 
> Just a bit apprehensive!!
> 
> Mike


Mike
Yes I've got stock ceramic turbos and a Power FC mapped by TR Racing at 1.0b,- that was 15k miles ago and although I don't have the pedal to the metal all the time, I do like to red line it, that's what they are for!

You should be fine as long as you warm it up & cool it down properly with regular oil changes.


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## Pete G (Aug 18, 2008)

nightcrawler said:


> ive got an r32 stock without a boost controller. if i remove the restrictor (which will give you boost up to 1bar) do i still need a boost controller?
> 
> i dont have any plans of going above 1bar but i feel my previous impreza is more faster than my gtr =(
> 
> ...


You won't need a boost controller,- I haven't got one, they are for cars with bigger turbos running higher boost where you might want to restrict it to 1.0-1.2b for normal driving then switching to max when the mood takes.

I took mine out by loosening the hose clip then taking it off and nipping the hose just below the restrictor and waggling the hose back and forth to work it up to the end until it came out. It is just a brass ferrule like the olive in a plumbing compression joint, only smaller.


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## nightcrawler (May 7, 2010)

Pete G said:


> You won't need a boost controller,- I haven't got one, they are for cars with bigger turbos running higher boost where you might want to restrict it to 1.0-1.2b for normal driving then switching to max when the mood takes.
> 
> I took mine out by loosening the hose clip then taking it off and nipping the hose just below the restrictor and waggling the hose back and forth to work it up to the end until it came out. It is just a brass ferrule like the olive in a plumbing compression joint, only smaller.




is it the pcm valve?

i had a look under the bonnet and i saw PCM valve which has 2 hoses clipped on. one has a yellow marked around it. do i just simply take that end off and thats it? what about the other end and what do you mean by "nipping the hose just below the restrictor and waggling the hose back and forth to work it up to the end until it came out"? sorry i just didnt get it.

is this safe? coz im planning to get an hks evc 6 soon to achieve only .82bar of boost to be on the safe side.

thanks dude


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## MS33 (Jun 27, 2007)

Well guys, just tried out the car and it pulls like a train, needle straight to 7mmHG and sits there, no spiking or anything, really great, still feeling apprehensive but see how I get on.

Thanks again pete.

nightcrawler, yes, the pipe with the yellow band and just wiggle it up and if you want to replace it just push it back down with the blunt end of a drill peice....simples!!


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## miragev (Apr 11, 2007)

MS33 said:


> Thanks miragev, I've removed the restrictor and will give it a run later.
> 
> Will let you all know how I got on...fingers crossed!!! :thumbsup:


okay mate ...:thumbsup:


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## nightcrawler (May 7, 2010)

MS33 said:


> Well guys, just tried out the car and it pulls like a train, needle straight to 7mmHG and sits there, no spiking or anything, really great, still feeling apprehensive but see how I get on.
> 
> Thanks again pete.
> 
> nightcrawler, yes, the pipe with the yellow band and just wiggle it up and if you want to replace it just push it back down with the blunt end of a drill peice....simples!!



nice to know about that dude.

ill try mine tom, and see how it goes. so i just pull the hose with a yellow band out of the PCM valve right? simple as that. no adjusting etc. as i dont have a boost gauge as well.

would appreciate if you or anybody can confirm this as this is the first time im going to touch my engine 

thanks


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## miragev (Apr 11, 2007)

nightcrawler said:


> nice to know about that dude.
> 
> ill try mine tom, and see how it goes. so i just pull the hose with a yellow band out of the PCM valve right? simple as that. no adjusting etc. as i dont have a boost gauge as well.
> 
> ...


no....
the hose with the yellow band has inside it a small plastic grommet remove the hose take out the plastic grommet and then replace the hose ..5 mins ..sorted


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## Pete G (Aug 18, 2008)

nightcrawler said:


> nice to know about that dude.
> 
> ill try mine tom, and see how it goes. so i just pull the hose with a yellow band out of the PCM valve right? simple as that. no adjusting etc. as i dont have a boost gauge as well.
> 
> ...


When you have taken the restrictor out (it's brass), refit the pipe.


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## DrGtr (Jul 18, 2009)

it would be nice if someone take some photos just to show to the people how simple it is.


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## JapFreak786 (Aug 29, 2003)

stupid question but i gotta ask,running 2510's on my car btw,but running 1bar of constant boost isn't going to affect my mapping is it? re-mapped on a power fc by the way...


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## nightcrawler (May 7, 2010)

@miragev

thanks for that dude. i almost did it wrong!

@peteg

thanks dude, much appreciAted.


@drgtr

yes it should have been much eAsier if there was a pic




ive removed the brass guys! thanks!
ill have a go later and see how it goes.
hopefully not blowing up my engine.
pardon for my stupidity! hahaha


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## Pete G (Aug 18, 2008)

DrGtr said:


> it would be nice if someone take some photos just to show to the people how simple it is.


OK










Slide the clip down the pipe past the restrictor










Carefully remove the pipe and feel along the pipe to find it then nip it just below the restrictor









Gradually work it up to the top










and out then replace the pipe and clip


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## nightcrawler (May 7, 2010)

Very nice and helpful peteG.

I managed to take the brass off but I accidentally split the hose right before the yellow mark
So I just cut the hose instead. Is that still ok? That's not a problem, is it?only an inch of hose but I managed to place the hose back to the valve.

Thanks


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## DrGtr (Jul 18, 2009)

Pete G thanks a lot i wish i could do it but i am not with the car now. Now its a helpful thread to everyone. I am really curious to see if my ukspec which already runs 1bar have one restrictor or not. Just a stupid question when you insert a boost controller do you cancel this one? yes isn't it? or this has the sensor for reading the boost in the screen inside the car?


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## nightcrawler (May 7, 2010)

Same question here. Want to have a defined boost so still planning to get an EVC. 

Now that I have taken the restrictor off, what boost am I running now?

Thanks


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## freakazoid3 (Jan 19, 2008)

Without the restrictor you'll be at 1 bar off boost


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## Shoryuken (Jun 20, 2010)

Don't want to sound like a broken record but is this 100% confirmed safe and will stay at 1 bar maximum? It's just that there are a lot of websites saying different stuff like it might go past 1 bar and that the stock ecu is set up to do only 0.6 bar and if you remove the boost restrictor, detonation will occur.


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## nightcrawler (May 7, 2010)

Shoryuken said:


> Don't want to sound like a broken record but is this 100% confirmed safe and will stay at 1 bar maximum? It's just that there are a lot of websites saying different stuff like it might go past 1 bar and that the stock ecu is set up to do only 0.6 bar and if you remove the boost restrictor, detonation will occur.


i removed my restrictor as soon as i read this thread. my car run smoother and faster. but if you want precise boost, then get an ebc buddy so youll be worry free. :thumbsup:


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## MS33 (Jun 27, 2007)

What ia a ebc buddy? Never heard of this.


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## nightcrawler (May 7, 2010)

MS33 said:


> What ia a ebc buddy? Never heard of this.


electronic boost controller dude :thumbsup:


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## RudeBoy (Jul 10, 2008)

cool info, gonna look and see if mine has the brass restrictor tomorrow


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## FreakensNL (Nov 10, 2010)

i have got a problem with it, i readed the manual, and it sayed to just remove the restrictor, so i did...
but after driving around it began to hold back, under full boost it spiked and it sounded like a misfire

so my questions:
do you have to remap it?
can you also drive on 98 octane or do you guys put in octane booster?


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## Samwest (Feb 23, 2009)

I wouldt remove the restrictor, its there to stabilize the boost, my advice, is get a boost controller. If you remove the restrictor and have a decat, then your boost will increae significantly. Dont remove the restrictor. I did and then put it back and got a BC


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## FreakensNL (Nov 10, 2010)

i still have a cat, everything is original on my sky, except for the walbro feul pump
i had some boost spikes on my silvia with the manual BC
but this looks like detonation or something, it sounds like launch control, when accalerating it goes fast but misfires 3 or 4time whene full load is applied


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## Samwest (Feb 23, 2009)

FreakensNL said:


> i still have a cat, everything is original on my sky, except for the walbro feul pump
> i had some boost spikes on my silvia with the manual BC
> but this looks like detonation or something, it sounds like launch control, when accalerating it goes fast but misfires 3 or 4time whene full load is applied


well just changing the fuelpump wouldnt give the car more fuel unless changing injector or do a remap. So either you are low on fuel on full load, or maybe you can check your coilpacks and sparkplugs if thats the case. Thats just my tips


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## FreakensNL (Nov 10, 2010)

coil packs i tested, they where ok, sparkplugs are also new

i thought that maybe more people had this problem


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## 400gtr (Sep 20, 2009)

Just wondering on my 33 Gtr it has has the ecu chipped/remaped to increase boost to 1 bar, question is will I still have the restricktor on and if so what will happen if I take it out ie boost over 1 bar or no difference I can't get to car to check as it is in storage


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## Samwest (Feb 23, 2009)

400gtr said:


> Just wondering on my 33 Gtr it has has the ecu chipped/remaped to increase boost to 1 bar, question is will I still have the restricktor on and if so what will happen if I take it out ie boost over 1 bar or no difference I can't get to car to check as it is in storage


Chances are that you will go lean if you remove it, do you have standard ceramic turbos? if so dont go over 1 bar boost.


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## 400gtr (Sep 20, 2009)

Standard turbos, I have no plans in removing the restrictor just wondered what if,


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## FreakensNL (Nov 10, 2010)

do you have to remap the ecu if you remove the restrictor, that is more my question


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## SteffanChyzak (Sep 12, 2010)

My R33 GTR was restricted and runs fine at one bar. Other way to do it safely is to get an electronic boost controller. These bypass the ecu and control the boost levels safely. R34 turbos are steel internals so can handle 1bar all day, older ones are more prone to breaking. Mine ran at 1.2 and held boost fine on the dyno. Shame the fuel pump couldn't manage to keep up and died but is now replaced. (another story another thread yes I know )


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## SteffanChyzak (Sep 12, 2010)

You don't need to remap the ecu. What is a good idea though, is that whenever you change a part of your car, eg: new filters, plugs, boost restrictor etc, is to disconnect your battery, step on the brake to get rid of any power, and reconnect it. This resets the self learning part of the ecu (short term memory if you will). Make sure that your wheels are straight when you do this as it can sometimes mess up your hicas for a while. Then let it idle for a good few mins and go drive it. It will pick up the new boost and work out whats going on


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## FreakensNL (Nov 10, 2010)

SteffanChyzak said:


> You don't need to remap the ecu. What is a good idea though, is that whenever you change a part of your car, eg: new filters, plugs, boost restrictor etc, is to disconnect your battery, step on the brake to get rid of any power, and reconnect it. This resets the self learning part of the ecu (short term memory if you will). Make sure that your wheels are straight when you do this as it can sometimes mess up your hicas for a while. Then let it idle for a good few mins and go drive it. It will pick up the new boost and work out whats going on


some helpfull info, so when mapping they just put it a bit more lean (on the edge)???
what kind of octane gas do you put in to it?
here, in holland the best gas you can get is BP ultimate and this is supposed to be 98/99 octane

how long does it take after resetting before the engine has to run smoothly?


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## Daniel Gray (Sep 10, 2010)

Can you do this on 95Ron? The best fuel you get in Shetland Islands is 95 RON. This is with 2x Apexi cone filters, Nismo front pipes, Abbey De-cat, new HKS Hi-Power 409 cat back, HKS 40 plugs. Standard apart from that mods. 1995 BCNR33 Non V-Spec import. 40,000miles. Thanks again, Daniel.


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## kannibal (Oct 1, 2010)

if we remove restrictor, it will increase to 1 bar , but if we drill the restrictor a little bit, it would make 0.8, bigger 0.9bar??

ps still have ceramic :chuckle:


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## edd_x2 (Jan 10, 2009)

i did it to mine and it worked but after a couple of mins it went into some sort of safe mode and would only boost to about .5 turn it off for half an hour and it would reset its self for a bit ...


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## samgtr (Aug 4, 2010)

im thinking of doing this but worried about the turbo shitting them self in the engine lol


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## MrGT (Jul 6, 2009)

just fit a electronic boost controller, no need for the stock item or restrictor at all then.


Tib


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## 34-gtr (Oct 10, 2010)

hi guys
if you cant see the yellow tag where else could it be on the r34. iv also heard the 34 doesnt have a brass restrictor but increses in boost when the hose is removed ???


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## TEN57 (May 29, 2010)

I ran on standard turbo's with restrictor remove for quite some time without issue. Didn't do a lot for performance though


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