HOWTO: RB25DET High Boost mode with standard solenoid

[smok74]

I too blocked off the top vac line from the solenoid to the Tee-piece. A lot of people says that this has no effect on performance but I think this should be looked at as the solenoid is obviously hooked up to the ecu, and by eliminating this device, would it effect the way the ecu makes it's calculations? Ive noticed my '97 serII is drinking a bit more after I blocked off this line.

The car will obviously still run, but what I'm really concerned with is if the engine is gonna run leaner/richer......i.e does this boost solenoid effect the way the ecu deliver the messages to the fuel system.....I doubt this solenoid is an independent device and it could be associated with the rest of the system in some way, would it alter the other parameters by turning it off?

[smok74]

Chrisgero, this happened to me too, but what actually happened was the vac line from the boost controller to the actulator wasnt tightened properly and popped off when I was givin it, the bitch peaked somewhere around 20 - 25 psi..... mine too made a huge-ass 'POP' as if the turbo had exploded, I freaked right out.

[kjb_r33]

Blocking off the hose to the solenoid will just give you no boost increase as it stops the bleed off of pressure. Bypassing the solenoid is asking for problems as the solenoid itself is also a restricter, bypassing it will just allow uncontrolable boost. The is no feedback from the solenoid to the ECU as it is an ECU output, simply switched to ground by the ECU to turn the solenoid on, thereby letting the bleedoff occur. The only reason fuel consumption would increase by turning the solenoid on all the time, or sooner, is because boost is increasing earlier, therefore more fuel is needed.

[imad]

thanks guys but i was wondering ,if i hooked the two ends of vacum ,whats the actual boost i get ?would it be the maximum boost ,in my stock rb25det turbo?

[kjb_r33]

which 2 ends??

if you took both hoses off the solenoid and joined them, you would get very high boost, as the solenoid restricts the bleed off.

[ricsvtr]

so the solenoid works just like a bleed valve right?

[kjb_r33]

Thats all it is, an UNadjustable bleed valve. They use that design so that if anything goes wrong, (open circuit to the solenoid) it doesnt go above the low boost setting.

[ricsvtr]

whats the best way to adjust a bleed valve anyway? ive just bought my car recently and it has one on it but i haven touched it. its supposedly set to 7psi but ive never really seen it go past 5psi. im thinking that the bleed valve is closed completely and seeing that the solenoid would have been disconected im just on low boost all the time.

[hanyou]

did this mod jus then haha wat a good find! scared to do it at first but yeah worked out all good i didnt even use that lead wire.. i jus cut the black, stripped it and wrapped it around the bolt haha same thing... gg paulr33 wid this mod

[paulr33]

haha no problems. glad your enjoying it. someone else had done it long before ive have but they never posted how to do it so i cant take the credit for all of it, i just tried it once after looking at the rb25 diagram and thinking how it could work and then tried it and it worked. enjoy

[hanyou]

by doing this mod , will it effect the running of my power fc (which i havent installed yet)?

mate ive got a power fc and i done the boost thing and the only thing i see going wrong is my petrol hahaha but other then that love it..

[RaMpAgE R33]

Hey all i just signed up cause i got a 94 r 33gtst

Just askin but when i got the car it wont run over 5 psi i tried a little pipework and ran it wayyyy past 7 pound cause the overboost mechanism kicked in lol. (put it back soon after)

i wanna do the wire job to test it but does neone have an idea on what could be wrong with my car?????

[MsG_ChRiS]

lol i thought i broke my car till just now lol!!!

i've chopped my wiring up now to =(

ahhh well least now it might work ???

dont know if this will help ne1 i got some of those lil screw down terminals from jaycar i think they cost a $1.50 made doin this a breeze and its also reversible if i want =)

[shong86]

can someone give me instructions on how to make a switch for the grounded bypass..?? Much appreciated..

Regards,

-SHONG86-

[mad34]

HI buddy,

Sounds like a quick and easy mod. Im just wondering it you can do it to an auto??? i have r34gtt tiptronic. i think they run slightly higher than standard boost when stock?? or is it just always on full boost no step up in boost levels after certain rpms like the step which this mod gets rid of?? I am not too sure

i would really like to know though coz if its the same as a manual i will do the diy mod asap.

any help would be appreciated

[justin911]

i got no idea bout auto's/34's etc.. but when your driving around do you get extra boost at 4500rpm ?

If you do, then you should be right to do the mod. Either way though, it only takes a second or 2 to fix back up if it doesnt work.

[Links]

Could someone please send me a link for the type of switch I would need to use for this setup. I want to put one in so I can flick it one way for 5/8psi other way for 8psi..

I've bought one from dick smith that has 3 prongs on it and I was guessing it should work however I can't even get it to work with 2 little LED's and a battery.. so either I suck - or I've bought the wrong switch - which I think is the case (hopefully)

[Links]

Never mind - i've sorted it myself - i've purchased the following:

http://dseau.resultspage.com/search.php?p=...34&site=&w=7701

for anyone that doesn't know anything about electronics you need a SPDT switch which is the following:

SP = Single Polarity - DT = Dual Throw - which pretty much means that if you flick it one way 1 thing turns on - flick it the other way the other thing turns on..

good luck!

[RedEmblem]

Could this damage the turbo?

I mean, to the turbo would this be like driving around @ 4500rpm+ all day?

:confused:

[Links]

installing a switch as i'm doing will stop this issue..

also - it only runs 8psi when it's spooling.. so really.. it's up to you and how hard you want to drive it...

shouldn't be to much of an issue.. most people drive with 10psi aftermarket..

thing you should be more worried about is the boost solenoid - having 100% grnd all the time..

put a switch in and only use it when you want to..