HOWTO: RB25DET High Boost mode with standard solenoid

[PTR33]

The other option for removing the 2 stage boost is to pull the two hoses off the solenoid and just use a small piece of pipe as a joiner. As long as you leave the original pipe with the restrictor in it in place you will get the "hi boost" pressure all the time. (about 7 or 8 PSI)

What you can also do is replace the small hose with the restrictor with a piece of vacuum hose and play with the size of the hole in the joiner pipe. I found that filling it up with "Lumiweld" (aluminium solder) and drilling it to 7/64" (2.78mm) I get a momentry spike to 12PSI which drops off to 10PSI and eventually decays to about 9PSI by redline.

The difference in the driving experience is fantastic.

Even just getting rid of the solenoid out of the system and getting standard hi-boost all the time makes the car much more fun to drive.

150% recommended.

[Airzone]

BTW, I did this about 12 months ago on a sickie. Car still works fine

[chrisgero]

I have recently purchased this Skyline and decided to follow these simple instructions. The Skyline had an adjustable boost control and either way I turned it to Positive or Negative it had the same boost Max 9lb.

Being new to the Skyline movement from the humble SS Commodore, I have been converted. However, not being a mechanic I placed all the hoses after removing the boost controller back to the standard solenoid and re-wired the white wire to the body of the car. I then tested the theory by taking the car for a spin around the block and it spiked to 20lb boost, it scared the S@#@ out of me because the Skyline backfired and I thought I blew the turbo, it was only for a split second then i backed off straight away. I got back home and found the hoses were in the wrong position.

.

Now the car is pushing 7 - 8lb and it is smooth. Could someone please tell me what the hell I did wrong. Have i damaged anything that will haunt me later. Im good with V8's but not with these TURBOS.

.

Chris , Sydney. :flamed: :throwup: :Bang:

[Nozila]

i think someone mentioned that it may be the black wire which is the ground wire and not the whire one.

[BEN 0]

hi im new to this business and my skyline i recently perchased at this setup already installed but my r33 has a stock 34 cooler and a custom air intake and 3' exhaust. with this boost setup my car runs just under 10psi.

is this normal?

if so can i run a switch of the ground wire and would the off position run the stock boost setup?

thanks for your time anyone?

[JAS-25T]

i think what would have happend when your car ran 20psi, is that the actuator wasnt connected and it just boosted infinatly.

ive set up a switch on my car, but found i loose around 50km per tank of fuel in economy if i run the 7psi constant thing so i switch it for having fun then switch it back off.

[Zoix]

what about cold starts? I dont hammer my car till the a/f meter on my blitz pen timer starts to work(means its warmed up)

Just wondering if this would do damage at all?

[Guest RedLineGTR]

Can’t you just disconnect the solenoid via the plug? I know it removes the two-stage boost but at what level does it keep the boost?? A while ago I did some tests with a aftermarket boost gauge (don’t have it now) is when I just unplugged the solenoid the car ran the same boost through the rev range as to before with the two stage sh1t.

[paulr33]

with the plug taken out or disconnected it stays in low mode which is 5psi, aka the solenoid doesnt open any wider

[R33vit]

hi im new to this business and my skyline i recently perchased at this setup already installed but my r33 has a stock 34 cooler and a custom air intake and 3' exhaust. with this boost setup my car runs just under 10psi.

is this normal?

if so can i run a switch of the ground wire and would the off position run the stock boost setup?

thanks for your time anyone?

Sounds like your car has a R32 GTS-T Acturator fitted which runs 10psi

[BOOST ON]

i am new to the skyline scene and i am looking at raising the boost... but i am more interested in like 10-11psi not 7-8.... i put a bleed of valve on for the moment becoz i am going to do all my mods in one hit... what i did was run the bleed of valve and diconected the soleniod by running one peice of vacum line like a loop from both of the nipples on the soleniod? becoz this is no longer connected to the wastegate shouldnt it not effect the controlling of the boost at all ?? but yet i can still only make 5 psi ? any help regarding would be super... thanks mick

[(B1) MR_fanny]

Sounds like your car has a R32 GTS-T Acturator fitted which runs 10psi

actuator as in boost solenoid?? so does this mean if i get an r32 one it will run 10psi...is it an easy fit?? i think id preferr this to a bleed valve.

[Nozila]

i believe the r32 runs 7psi all the time.

Im not quite sure about that, are you talking about stock or modded - im assuming stock. But my brothers run 11 psi stock. I believe its due to the turbo being ceramic.

[VIPERGTSR01]

I tried this mod today and I must say the car feels alot more reponsive at rpms below 4500.

[Sciby]

To add on my 2 cents...

You don't need the solenoid, yank it out. Connect the tube that connects to the top solenoid straight into the T piece that the bottom tube from the solenoid connects into... remove solenoid, throw it over your shoulder.

I also have a boost gauge with about 2m of tubing on it, so it allows it to hit the (so I'm told) factory max boost of 10psi. Works well. It's the stock turbo and no EBC, so I have no need for bleed valves or whatnot until I buy something better.

[fooey]

Without the solenoid, you should only be running max of 5psi (wastegate spring), if you are running 10psi, then you might be running a R32 wastegate actuator spring (which is apparently 10psi).

[Sciby]

Hmmmm... as far as I'm aware, the 33 was supposed to be 10psi max as well. *shrugs* It works, so I no complain.

Also, I believe mine is totally stock. The car was not really fiddled with when I got it. Only got mags, suspension and cat-back... no real power upgrades to speak of, so it'd be a wee bit weird if they changed the actuator spring... *scratches head*

Anyone with a definitely stock 33 turbo want to remove the solenoid from the picture and see what happens?

[benl1981]

You can only get as low boost as what the actuator opens the wastegate at.

The solenoid can only "trick" the actuator pretending there is less pressure there than actually is. Hence if you remove the solenoid altogether (connecting lines together) you should only get 5 psi (or the base setting of the actuator).

If you pull the hose off and leave them dangling then the actuator won't sense any boost and you will get heaps of boost, apparently the wastegate will open eventually due to the force of the air acting on the wastegate (depends on the spring tension in the actuator) anyway you will probably see 20psi or so before this??

[Sciby]

And see your turbine spit out into the exhaust 5psi before that.

My 'line is an early 94, so since I'm getting 10psi, it may be that I got an actuator off a 32 turbo. *shrug*

I'm happy with it at that until a new turbo comes along.

[benl1981]

Yeah - I wasn't suggest you do that.

Just checked on mine, the solenoid -ve was the black and the white was carrying the +ve 12v

Might try this mod, seems fairly good for some extra low end. Why would Nissan put such a thing on? Traction issues maybe...? Cant see it really helping the engine to last longer..

I was told to get a FMIC before playing with boost but this seems fairly harmless as the car is running the higher boost at higher rpm anyway..

Any thoughts?