HOWTO: RB25DET High Boost mode with standard solenoid

[ranicx]

just wondering... i did this mod, but im unsure if it has actualy changed anything. but on the stock boost gauge (one in the dash), half way mark, what psi is that?

its a gts25t 95 model by the way

[Links]

+7 on the gauge is 14.5PSI I do believe.. so 1/2 way is about 7PSI.. should prob go a bit higher than that..

[ranicx]

ah kool.. well i guess the mod worked then =)

reason y i was unsure was i didnt cut the black wire, but striped it back on one section behind the black cover sleve that goes over both the wires, and then attached the grounding wire there, so that if the cops do inspect it, it wont look like anything has been changed cause its hiden

[soon2b33]

"+7 on the gauge is 14.5PSI I do believe.. so 1/2 way is about 7PSI"

wow, why is +7 14.5psi??

yes i had the same problem, saw that it only went just over halfway so i wasnt sure if it worked or not, so i changed it back.

pity i didnt try it just with myself in the car, everyone wanted to jump in to see what the difference was.. so with 4 people.. went even slower than normal obviously

[paulr33]

"+7 on the gauge is 14.5PSI I do believe.. so 1/2 way is about 7PSI"

wow, why is +7 14.5psi??

yes i had the same problem, saw that it only went just over halfway so i wasnt sure if it worked or not, so i changed it back.

pity i didnt try it just with myself in the car, everyone wanted to jump in to see what the difference was.. so with 4 people.. went even slower than normal obviously

<{POST_SNAPBACK}>

stock boost guage is in mmhg

7 mmhg = 1 bar = 14.7psi

[SDEWY5]

i installed a bleed valve and looped the two hoses going into the 5psi solenoid and all was merry when i booted it, and as soon as i got to 4500rpm the engine just went nuts and backfired, and hesitated shockingly before going back to normal, pulling like a train at roughly 5000rpm..any ideas? i guess the ecu doesnt like the boost solenoid not doing anything...was this hesitation in the engine the knock sensors retarding my timing?? it scared the hell outta me...happened a couple of times...thought it may have been overboosted by my bleed valve but in disconnectiong it, it made no difference...ill just ground the solenoid...should be safe that way..anyway..can someone explain what happened to make my engine go all crazy?

[SDEWY5]

nevermind..solved the problem...im such a retard i totally bypassed the wastegate actuator so it was bleeding off all vacuum..so wastegate just refused to open...this is very bad....i musta hit roughly 20psi at one stage...fu@king so lucky it didnt damage anything..

[RyanN]

i'll give it a try tonite with my er34 semiauto and see what happens. Might do the safe option and wire up a small switch in the engine bay to constantly ground it.

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yay! more power!

not too noticable in an auto but there is slightly better acceleration in the lower rpm range, no longer need to kick the auto down a gear.

[ct999]

I tried this and it works mad!!! Love it. What i also did though was i used a change over relay, i put a on off switch on the dash when the switch is off the computer controls the boost and in the on position the solenoid gets gounded,

its the best possible way this mod can be done without any effects.

Change Over Relay Conections

85 - Earth

86 - switch on dash with 12+ volt

30 - to solenoid

87 - to the wire you cut going to computer

87a - Earth

Hope this helps

Chris

[paulr33]

i dont have the original pics anymore or the solenoid. can someone take some pics of the mod done please and ill post them back to first post on page #1

[US_R33]

nobody is able to post up the pics of their solenoid and wiring for me??? i have about 30 minutes of daylight left and really would like to have this done before i go out cruising tonight

the next best thing would be if you could just direct me as to where to find this solenoid.......i've looked around the engine bay but i'm unable to find it

Late,

Daniel

[justin911]

the solenoid is near the stock airbox.

Its just behind it to the right... its like a funny looking gold thing with 2 hoses coming out of it...

Its next to some liquid container if i recall correctly, cant remeber which one..

but yeah its right near the airbox..

nobody is able to post up the pics of their solenoid and wiring for me???   i have about 30 minutes of daylight left and really would like to have this done before i go out cruising tonight

the next best thing would be if you could just direct me as to where to find this solenoid.......i've looked around the engine bay but i'm unable to find it

Late,

Daniel

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[US_R33]

thanx Jason

okay cool i just checked it out......but my wires aren't white OR black

i have a light green wire and a blue wire with a white chaser (stripe)......anybody know what to do with these colored wires???

Late,

Daniel

[US_R33]

Also get rid of the restrictive gause either side of the AFM, again, what is it going to stop other than air? If something is big enough to break thru the air filter, it deserves to break your afm and will regardless...

<{POST_SNAPBACK}>

if you're talking about the screen on the AFM i wouldn't remove that. That screen is there in order to create a venturi effect on the intake air just before it his the AFM device, this is important as it helps your AFM accurately monitor the amount of air coming in much better than it would w/o the venturi effect.

I know people who have removed this screen from their AFMs (not skyline owners) and the end result caused them to have to go out and buy a brand new unit. Just thought i'd put that out there

Late,

Daniel

[paulr33]

yeah dont remove the mesh, its a bullshit mod. keep it there

[US_R33]

did this mod a little bit ago :D:D

great mod.....car feels MUCH more alive in the low RPMs now.....well worth it

Late,

Daniel

[RyanN]

whats the boost after doing this mod? i noticed that it seems to go pretty close to 1+ on the boot gauge.

[justin911]

7psi

whats the boost after doing this mod? i noticed that it seems to go pretty close to 1+ on the boot gauge.

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[RyanN]

7psi

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so stock boost is about 5psi this mod increases it to around 7, isn't 1+ about 14psi?

[justin911]

nah stock boost is 5 - 7psi..

when you go past 4500rpm the boost solenoid thing opens and gives you the extra 2 psi.. so you get 7 in total..

What do you mean 1+ ?

7 on the stock boost gauge means 14psi if thats what your talking bout ?

so stock boost is about 5psi this mod increases it to around 7, isn't 1+ about 14psi?

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