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View Full Version : Boost restrictor pill Removal



Scubasteve
11-06-2009, 04:35 AM
Just wondering has anyone removed this boost restrictor pill and what changes good or bad have been experienced? I have a 3" Aftermarket System Fubi and HKS Drift filter but no aftermarket ECU. Any help thanks guys.

Kitty's VR4
11-06-2009, 05:48 AM
I've done it....

Definitely notice the difference, not great gains but it is noticable, if your light on the throttle - no real difference to economy. If moderate (bit of spirited and normal driving), lost about 50k's per tank...... during track day got 175km from 45litres...... so thirsty as hell if your into it.....

In the above pic the restrictor valve appears to be plastic, mine was a brass valve.... additionally great care should be taken removing the valve from the solenoid body, with under-bonnet heat the plastic of the boost solenoid body can become a little brittle, I had no problems removing mine carefully, but I know of a few members that have snapped the vacumn hose tube off, so use kid gloves........

I used a small crochet hook to get mine out...

Scubasteve
11-06-2009, 06:28 AM
Thanks Kitty, u can't get away from Q's LOL

Kitty's VR4
11-06-2009, 06:35 AM
I dont have a boost guage fitted so I don't know what difference it made to psi reading, have also fitted series 2 -2002 ECU since then... kitty feels to be 10-20% up on power..... a seat of your pants reading...... i'll get a better idea at the next dyno day

pu-11-me
11-06-2009, 08:12 AM
Just get a $30 MBC off ebay lol..... SOOOOOOOOO much easier

If you want regulated and controllable boost, get an EBC :)

The Vee
11-06-2009, 11:28 AM
Surprised to hear of power gains - in my understanding all it does is restrict the the amount of rapid change therefore smoothing changes in boost not actually altering the final amount. I have got mine completely bypassed and I do find that when accelerating, if you come off throttle quickly it will produce a jolt as I think the rapid change to off boost confuses things slightly!

Turbo_Steve
11-06-2009, 01:50 PM
That's also possibly caused by your dumpvalve "overdumping". That's what happens on the Evos.

peter thomson
11-06-2009, 01:51 PM
Surprised to hear of power gains - in my understanding all it does is restrict the the amount of rapid change therefore smoothing changes in boost not actually altering the final amount. I have got mine completely bypassed and I do find that when accelerating, if you come off throttle quickly it will produce a jolt as I think the rapid change to off boost confuses things slightly!

I also get that jolt with my VR4

Kitty's VR4
11-06-2009, 02:29 PM
Ummm, I haven't experienced the Jolt yet..... jolt... sounds violent..... my thinking was it reduced the boost spike, for example it smoothed the boost to an even 7psi, with the restrictor removed boost would spike out to 9ish psi, thats how it read in some of the japanese tuner forums.......

I think its time to buy a boost guage to see exactly whats happening, do some boost readings with the restrictor in and then again with it out......

Certainly felt like it made a difference...... was it the placebo effect???????

MPBVr4
11-06-2009, 04:08 PM
That's also possibly caused by your dumpvalve "overdumping". That's what happens on the Evos.

Yep I get it now with a GFB Hybrid BOV fitted when half open to Atmosphere.
Close it for recirc only and no jolt.

White Lightning
11-06-2009, 04:15 PM
That's also possibly caused by your dumpvalve "overdumping". That's what happens on the Evos.

I remember the JD used to do that when I drove it for a while ... that had an HKS SSQV fitted (and the Blitz EBC) and I thought it was probably caused by that.

Just one of the reasons I have decided not to fit a VTA dump valve to mine to date.

MPBVr4
11-06-2009, 08:19 PM
The Hybrid one is OK if it's only open a bit (not half way) It's still enough to make small kids and cat's run for cover:d
I will grow up one day/pan

Turbo_Steve
11-06-2009, 09:35 PM
It's all down to the spring rate, and how big the holes in the dumpvalve are.

Scubasteve
12-06-2009, 12:08 AM
Ok i'll test it with my boost gauge, but..... where the hell is it. I can't find anything that looks like that or even know where to begin please point a noob in the right direction :)

matchtheclown
12-06-2009, 12:19 AM
Follow the red tipped hose that is connected to the intake pipe which is on the end of your throttle body.

You will need to remove the intake pipe from the throttle body and bend it back out of the way because it is underneath it.

wintertidenz
12-06-2009, 12:46 AM
Here's some pics, excuse the weird piping - someone put my car back together the wrong way before I bought it.

You can see a pipe looped back in the top right corner, this is where the red tipped pipe starts:
http://i100.photobucket.com/albums/m23/wintertide/IMG_0097small.jpg

Clearer here:
http://i100.photobucket.com/albums/m23/wintertide/IMG_0233small.jpg

That pipe goes to two solenoids down here:
http://i100.photobucket.com/albums/m23/wintertide/IMG_0230small.jpg

The one with the WHITE connector is the boost solenoid.

Scubasteve
12-06-2009, 01:56 AM
Cheers guys where would VR4 Noobs be without u's. Probably driving Nissans or even worse Honda's lol

MarkSanne
18-03-2010, 08:11 PM
Did this myself after reading somewhere on here about these restrictors and thought I'd post up a few pics in the forums instead of links (I hate those linked-pics as they seem to stop working after some time, right at the time one needs them).

So here it goes:

Remove the air intake pipes for some clearance as much as you want. If you're used to fiddling around tight spaces and/or have small hands you might not need to remove this much (I removed the MAF too as I did that mod too).

WARNING: I read the plastic parts of these solenoid casings can get brittle so I removed the bracket (2 bolts) where 2 solenoids are mounted on first, then turned the bracket around and unbolted the 'white' one (white connector).

One hose didn't want to let go, so I used a very small screwdriver and pried/lifted the rubber hose. Carefully again! Then it came of without a problem.

Alright, here we go. Pics!

uploaded/1887/1268939094.jpg

uploaded/1887/1268939131.jpg

uploaded/1887/1268939158.jpg

I first used a small size paperclip that I bent slighty, but it wouldn't let go so I put the solenoid in a drill-clamp and on to the pillar type drilling machine with a very small drill. Ever so carefully applied pressure on it and within seconds without hardly any drilling done, the restrictor moved down a bit. Now it ws just a matter of using the paperclip method again to wiggle it out. All done within 5 minutes.

uploaded/1887/1268939183.jpg

AlanDITD
18-03-2010, 08:13 PM
im confused, thats two differnt parts of the car compared with what the firstpost in this thread is talking about.

MarkSanne
18-03-2010, 08:40 PM
That's why I like to take actual photo's and post them.

Nick Mann
18-03-2010, 09:00 PM
Alan - it's the same part. Just Mark has got actual pictures of the VR4 solenoid, whereas I would guess that the first post shows a "typical" boost solenoid and restrictor.

All the VR4 solenoids I have seen look just like the one in Marks photos. And as Kat says, the restrictor is normally brass.

scott.mohekey
18-03-2010, 09:01 PM
im confused, thats two differnt parts of the car compared with what the firstpost in this thread is talking about.

No, its the same bit. The picture at the top is actually from a GTO.

AlanDITD
18-03-2010, 10:37 PM
hmm ok, so on the bulk head theres also two solenoids that look like the first picture, and it definately had a weird blanking pill on it aswell...thats why im confused!

Mark - well done on your beautiful photography skills, i can only aspire!

MarkSanne
18-03-2010, 10:46 PM
hahaha thanks Alan, it's a 5/6 years old Sanyo compact digicam which I use as a 'garage-stuff' camera, but it does make pretty pictures despite it's age and all it's simplicity.

AlanDITD
18-03-2010, 11:09 PM
hahaha thanks Alan, it's a 5/6 years old Sanyo compact digicam which I use as a 'garage-stuff' camera, but it does make pretty pictures despite it's age and all it's simplicity.

Yeah they are very detailed tbh....pics like yours are far more handy for hobbiest mechanics than any service guide imo. well a combination of the two possibly :)

foxdie
31-05-2010, 04:44 PM
Okay, well, I thought I'd spend some of my bank holiday Monday on seeing if I could remove said pill, I got to the solenoid and both inlet and outlet weren't connected to anything..

I'm guessing that those of us with an Electronic Boost Controller no longer use the stock solenoid, and as such, don't need to remove this pill?

The Vee
31-05-2010, 05:29 PM
Yep the whole thing can be bypassed with EBC etc

Dom B
31-05-2010, 11:17 PM
The picture in the first post is from a website about tuning a VR4 or rather what the americans call a vr4 which to you and me is a GTO. Anyway the point is that the site is actually very informative and shows lots of dyno testing before and after pill removal etc if i remember rightly. If i can find it again i will post a link.

Dom B
31-05-2010, 11:22 PM
I am not sure if this is the website as original i think it is one of the ozvr4 guys.

http://www.rpw.com.au/shop/index.php/customer-vehicles-workshop-services-40/55-mitsubishi-galantlegnum-models/221--mitsi-legnum-vr4-awd-6a13-twin-turbo-271hp-atw

horseybusiness
07-06-2010, 01:08 AM
Just given it a go, after finally managing to drill out the restrictor :-) Good result, my car is def boosting more, getting a sustained 11psi up from around 9 before, no idea why this would happen? I

phosty
07-06-2010, 10:04 AM
A bigger hole in the boost pill allows the boost solenoid to vent more pressure from the wastegate actuators thereby allowing more boost.

Davezj
07-06-2010, 09:10 PM
so by removing this pill bit does that mean you now can not turn the boost down if you need to.

phosty
07-06-2010, 09:21 PM
How do you turn it down now? Do you use an EBC or similar?

Turbo_Steve
07-06-2010, 09:37 PM
All the restrictor does is make the boost spike more before settling. Removing it just makes the ECU boost control work worse, spiking all over the place: you'd do far better to just fit an MBC and have the option of going back to standard if you need it.

Davezj
07-06-2010, 11:11 PM
took the word out of my mouth Steve.

jb2815
08-06-2010, 09:23 AM
All the restrictor does is make the boost spike more before settling. Removing it just makes the ECU boost control work worse, spiking all over the place: you'd do far better to just fit an MBC and have the option of going back to standard if you need it.

hmm I've got a MBC but the solenoid is still plumbed in, should I be taking it out of the equation? The boost controller is one with a seperate T piece (turbosmart copy?)

Turbo_Steve
08-06-2010, 09:39 AM
Technically, your boost control will be more stable just using the MBC, however the VR4's boost control seems pretty noddy: I'm not sure it really notices!