So, last night I was having some drinks with another GT-R owner friend of mine (who coincidentally works for Nissan as a designer) and I asked about some free horsepower upgrades for the RB26DETT.

He told me about the in-line restrictor oriface for the stock boost control solenoid.

If you don't know, there is a solenoid on the R32 and R33 GT-R (maybe the R34, but I don't know for sure at this time) that has this little fitting in it to limit stock boost to about .7kg. A fairly well known secret down in Australia is that if you remove this fitting from the hose going to the solenoid, you can get 1.0kg off boost from your turbos.

But, be warned. Long runs at this boost level in the R32 and R33 can be hazardous to your turbos because your exhaust wheels are ceramic. If they get overheated, they have been know to grenade and cause all sorts of damage. Small burst here and there are fine, though.

To find this fitting, locate your stock boost control solenoid on the driver (left side if you are facing the engine bay) fender. There will be two hoses that are attached to it. One will have a yellow band about half an inch down from the solenoid. Squeeze right at that yellow band, you will notice that there is something inside there.

Here's how I got mine out.

Disconnect the hose from the solenoid and remove the squeeze clamp. Next, spray a very small amount of silicone lube down into the tube, but just a little bit.

Using a set of adjustable flat nosed pliers, easily squeeze the fitting up and out from the bottom, taking care not damage the hose. Just keep slowly working your way to the open end of the hose using this method till the fitting comes out. DON'T DROP IT! You may need to use it again in the future.

Replace the squeeze clamp to the hose and replace the hose on the solenoid. Test drive and enjoy 1kg of boost in your R.

The whole process shouldn't take more than 10-15 minutes for a somewhat experienced wrench turner.

What I noticed after removing the fitting was, of course 1.0KG of boost (although it did rise every so slightly higher when boost first came on, but settles right at 1kg very quickly and no boost creep), increased boost response, decreased spool up time.

**NOTE!!**Do not do this unless you have a boost gauge that is accurate. Either have one in KG/Cm or PSI. 1.0KG = 14.7psi.

If the boost pressure holds at over the limit of 1KG, you'll need to reinsert the fitting as it could mean the spring tension in the wastegate actuators is no good which will cause over boost and and you really don't want your turbos to go.

If you do need to reinsert the fitting, don't worry, you can still increase the boost.

Just take a drill bit set and find out which size drill bit fits through the fitting, then just increase the size a little bit till you get your desired boost level.

Isnt this old news lol?

Might be, but ya never know how many people don't know about it.

If you are all good I will tell you a similar trick to get about 1.5- 1.6 bar.

On stock turbos? I am hoping you're meaning aftermarket units. The stockers can't hold that much, right?

Stockers , only about 1.0 bar. 1.5 and they die pretty quick. Knock on the stockers, and they die pretty quick.

If you run 1.0 bar of boost, on a tuned ECU, on Cali 91 octane fuel, you will lose an exhaust wheel sooner than later. The MINES ECUs are notorious for that. I had so many customers lose exhaust wheels.

This is the same for GTS as well, same process. There was a detailed write up with pics a few years ago on SAUS. The GTS ones are on the opposite side near the power steering tank.

For the most part running a aftermarket boost controller will eliminate the factory one anyways so most people will not even run into this unless they stay stock. Mine has been sitting on my workbench for awhile now

Running a PFC with the boost kit will replace that as well, plug and play but sometimes requires a rewire of the plugs to the Apexi control.


Modified by Vandrel at 8:12 PM 1/29/2010

tyndago wrote:Stockers , only about 1.0 bar. 1.5 and they die pretty quick. Knock on the stockers, and they die pretty quick.

If you run 1.0 bar of boost, on a tuned ECU, on Cali 91 octane fuel, you will lose an exhaust wheel sooner than later. The MINES ECUs are notorious for that. I had so many customers lose exhaust wheels.

Sean, is there any way to by-pass the stock set up and just run a line from the boost source at the bottom of the intake to the actuators?

All that extra piping just appears to be soley for the control solenoid. Would make installation of a boost controller much easier, as well.

It should read whatever the vac pressure it's receiving. Off the top of my head I can't recall but if it's like the 25/20 solenoid it will have a connection to communicate with the ECU, if bypassed would probably kick a check engine light for you.

Best route is to go with a Power FC, pick up the D Jetro and toss out the MAF's. You can either run the PFC boost control kit which will let you set your levels in bar format via the commander from inside the car or you can upgrade your turbos for a external wastegate setup to control your boost which is what I run.


Modified by Vandrel at 10:18 PM 1/30/2010

LOL, so funny story. My front turbo lost the exhaust side turbine last night. I have been running this mod for about 6 months and theres only 51,000km on my motor. Time for a turbo upgrade lol.

Picture of the damage lol, HKS gt2530s on the way
Modified by nissans13240sx at 6:20 PM 2/7/2010