HOWTO: RB25DET High Boost mode with standard solenoid

[so_tred]

Hooked up a switch for this on the weekend, great idea to do so

[R33_Smash_Deamon]

hey some of my mates tried to do this to my car but stuffed it up

1st they spliced into the white and earthed it and the car wouldnt start

so then they tried the black wire and spliced it and earthed it n still no start

so we put it back to normal and it still dont start

all u hear in the starter kicking away

anyone got any ideas on wat it might be

thanks tom

[Kinks]

anyone got any ideas on wat it might be

yep - your mates are morons. don't let them near your wiring again.

they shorted the +ve feed from the ECU to ground. At worst, they've blown up your ECU. At best, it's just popped a fuse and if you replace it you'll be fine.

[R33_Smash_Deamon]

yep - your mates are morons. don't let them near your wiring again.

they shorted the +ve feed from the ECU to ground. At worst, they've blown up your ECU. At best, it's just popped a fuse and if you replace it you'll be fine.

yeah it was just a fuse, all fixed now and running 7 all the time

thanks mate

[tappet]

heads up to the people using a switch...

i just thought this may have a bad effect on the ecu...

i take it people are joining in a switch to run constant negative while "ON"

and the ECU signal while "off"................... ie splicing a switched earth with the ecu signal still working...

the ecu is not going to like the constant earth while the switch is "ON"...

if u cut the negitave wire to the solenoid and earth it on the solenoid side only it is fine...

u can even run a switch to the earth but u will only get 5psi with the ecu signal gone...

aletrativly u can run 2 switches that will sort out the whole problem...

1. cut the ecu's earth signal between the solenoid and the plug and add switch "1"

2. on the solenoid side of the of switch "1" add another switch ur constant earth wire "2"..

now when u want to run high boost

turn off switch 1... (cuts out ecu signal and any constant earth from burning out the ecu)

turn on switch 2...(constant earth to solenoid meaning 7psi constant)

if anyone has any q's please reply and i will explain further..

[tappet]

this is an even better way to go about it...

hi all,

I wired this mod up this morning, works well. I wired it to an {on/on} switch inside my car. This allows me to flick the switch one way which puts it to standard where the ECU grounds the solenoid at 4500rpm, and when i flick the switch the other way it grounds the solenoid straight away so it opens and i have full boost as soon as i put my foot down,

Thanks for the mod,,,,!!

Edited April 11, 2007 by tappet

[Hotwire]

My 2 sec pictures of how a switch would work. The grey wire section is just to represent where the original connections were. DO NOT leave the wire connected accross the switch.

Note I dont have a skyline yet which I have performed this mod on, its purely based on reading this thread.

Edited April 11, 2007 by Hotwire

[tappet]

^^^perfect..

at least someone gets what im talking about....

[Turbo Tim]

I just did the simple straight to ground mod.

I didnt see the point of switching it, im more than happy to control boost (and fuel consumption) with my right foot.

Oh yeah forgot to mention, definately worthwhile, car has the low down torque its been missing, makes it a bit more fun to drive thats for sure. Its how they should have come from the factory. It is easy to pull up full boost at low rpm though.

Edited April 15, 2007 by Turbo Tim

[evesdropping]

^^^perfect..

at least someone gets what im talking about....

I think a fair few people have used that method mate. It's been mentioned numerous times throughout the thread.

another +1 for this being an easy effective mod.

[gargantua]

Would anyone in Melbourne be able to do this mod for me? I live in the Southeastern Suburbs.

I have no clue on what to do ive never done this kind of stuff before, and knowing me I will break something.

[daxter]

I tried this last night, I cut the black wire and earthed the black wire coming out of the solenoid then taped up the black wire going to the ecu.

However nothing has changed, the car runs 5psi till about 4500rpm then goes up to 8psi, I have a boost gauge so I can see what psi I'm running.

So whats happing?? should I try find a better earth? I sanded back the metal in the engine bay then bolted the wire down, thought that would be a perfect earth.

Edited April 26, 2007 by daxter

[MotoMan]

Would anyone in Melbourne be able to do this mod for me? I live in the Southeastern Suburbs.

I have no clue on what to do ive never done this kind of stuff before, and knowing me I will break something.

Im Northeast... Heidelberg... can do it for you if you want... its not really that hard

[evesdropping]

I tried this last night, I cut the black wire and earthed the black wire coming out of the solenoid then taped up the black wire going to the ecu.

However nothing has changed, the car runs 5psi till about 4500rpm then goes up to 8psi, I have a boost gauge so I can see what psi I'm running.

So whats happing?? should I try find a better earth? I sanded back the metal in the engine bay then bolted the wire down, thought that would be a perfect earth.

thats actually quite strange. If you cut the wire from the ecu and it is now connected to nothing, it shouldn't change psi at 4500rpm. It should be hi boost the whole way, or if you have a bad ground it should be low boost the whole way. It can't change at 4500 if the wire from the ecu isn't connected to the solenoid.

Strange

Edited April 27, 2007 by evesdropping

[Munkyb0y]

EDIT: WARNING: DO NOT use my method - below.

I tested it and my boost gauge showed 14psi, and climbing.

My foot was only half way down, and revs had only reached about 4500.

Wouldve kept climbing if i didnt back off.

Hope i didnt F*CK anything. Any thoughts on that ?

--------------------------------------------------------------------------------------------------------------

strip a wire long enough to feed through the male clip and around into the contact point.

you can feed the wire in thru the back of the clip, exiting as seen in the pics.

clip it back together, ground the new wire , or run it thru a switch first, and the mod is done.

totally reversable, no cutting, and not very detectable if you use a subtle colour like black.

see pics coz my explanation sucks.

super delayed update......

the reason mine spiked like crazy was because i had a unichip boost module hooked up thru the ecu using the stock solenoid.

i wasnt aware of it at the time. so ingore my dramatic warning above.

[daxter]

thats actually quite strange. If you cut the wire from the ecu and it is now connected to nothing, it shouldn't change psi at 4500rpm. It should be hi boost the whole way, or if you have a bad ground it should be low boost the whole way. It can't change at 4500 if the wire from the ecu isn't connected to the solenoid.

Strange

I connected the wire back up and it just kept running the same. So I have know idea what’s going on there.

It does not matter anymore though, I got a FCD and a ball and spring boost tap, running 10psi quite happy.

[innocente]

Pre-warning : VERY LONG POST

Hi guys,

I have been researching on matters related to the stock turbo on the ER34 GTT in many forums including this one. I have been looking at very different inputs pertaining to this matter. I have attempted many small DIYs with my ER34 GTT since I got the car last year.

Anyway, a background to the car intake/exhaust setup. Stock ER34 GTT Manual 2000.

- Apexi dual funnel intake

- Apexi N1 3" exhaust. 3" from the turbo downpipe. Unsure of the cat is of a high-flow one or not.

- Stock ecu, turbo, I/C, actuator, solinoid from what I can see.

- Pivot speed meter X (for speed cut removal)

Mod #1 - Hoses change

-----------------------

- Noticed that the vacumm hose between the solinoid & intake (before turbo inlet) had a crack in the opening.

- Decided to change some hoses to Sard Silicon hoses. Got a couple feet of the 4mm & 6mm spec ones. Noticed that the 4mm is really approx 2mm unexpanded in original state and the 6mm being about 4mm. This was the same for other brands like Samco, HKS.

- Changed the hose between intake (after turbo outlet) to the T connector. Original 6mm -> silicon 6mm (4mm). Also reduce the length of hose by 30%. Did not put in the so-called "restrictors".

- Changed the hose between the T connector to the actuator. Original 6mm -> silicon 6mm (4mm). Also reduce the length of hose by 30%.

- Changed the hose between the T connector and the solinoid. Original 4mm -> silicon 4mm (2mm). Also reduce the length of hose by 30%.

- Changed the hose between the solinoid and the intake (before the turbo inlet). Original 4mm -> silicon 4mm (2mm). Also reduce the length of hose by 30%.

- Changed the hoses between the boost sensor and the intake (Just before the throttle plate area). Original 4mm -> silicon 4mm (2mm). Also reduce the length of hose by 20%. Kept the filter in place.

* Noticed the car does not boost as before. Prior to this the boost would be @ exactly the 0.5kg/mm2 mark (0.49 bar or 7.25psi). Yes I know the standard gauge is not very accurate. After the mod, the boost is @ about 0.4kg/mm2 mark (0.38bar or 5.8 psi ).

Mod 2 - High boost Solinoid Mod

-------------------------------

- After reading this post, decided to do the mod. Found a hazard lights switch from the scrap yard that fits the emply slot in the area where the switch to adjust the headlights angle sits. Yep. perfect fit with the clips and everything. The manufacturer of this switch is NISIN, JAPAN. Unsure of what car it is from. This switch has a built in light. Naturally decided to use the light Wired the mod to the solinoid and the light in parallel. So 12V would be given to both solinoid & light when the earth end is connected. The switch toggles between solinoid-ecu and solinoid-ground with light indication when the circuit is completed. Hence when I turn it on, the light would be on and the solinoid would open allowing air to be bled out. When the switch is off and when the ECU gives the Ground signal, it switch & solinoid will also turn on. According to this post, it only happens past 4500rpm.

The ECU toggling the solinoid to open @ 4500rpm is not true. With my setup, when I tested my car. The ECU gives the ground signal even @ 2200rpms. After a good half hour testing, I realize that whenever the boost exceeds 0 kg/mm2 the ECU opens the solinoid bleeding air to achieve the alleged 7psi. There is really no 2 stage boosting in the ER34.

After that mod, I changed my hoses again.

- Reverted the hose between the T connector and the solinoid. Silicon 4mm (2mm) -> Original 4mm. Kept the length of hose like the silicon 30%.

- Reverted the hose between the solinoid and the intake (before the turbo inlet). Silicon 4mm (2mm) -> Original 4mm. Kept the length of hose like the silicon 30%.

- Inserted the "restrictors" into the 6mm silicon (4mm) hose between intake (after turbo outlet) to the T connector.

Results : I now boost to approximately 0.7 kg/mm2 (0.69 bar or 10.15psi). At the change from 3rd to 4th gear, the boost then goes higher to 0.8kg/mm2 (0.79 bar or 11.6psi). Noticing my switch light, it too lights up way before 4500rpm. It lights up (meaning the solinoid is open) @ about a little before 3000rpm. Toggle my switch on with the solinoid open at all times. Same results.

Conclusion :

#1. The mod does absolutely nothing for R34 or at least my car. The ECU is absolute stock. I am starting to believe that the solinoid opening is triggered by something other than the 4500rpm. Perhaps throttle opening ? There must be some difference for the R34 to produce so much more torque (approx 360Nm @ 3200rpm) as compared to the R33 (approx 280Nm @ 4800rpm). So my switch acts merely as an indicator of when the solinoid is opened.. heh heh. Now, I press it to give me pure psychological performance improvements. Afterall, we need to lie to ourselves every once a while.

#2. The restrictors are there not to restrict boost but to restrict boost pressure from hitting the actuator quickly. It reduces the hose's internal diameter from 6mm to 2mm at 2 points. It's more like speed bumps for boost pressure feed to the actuator. Hence, having the restrictors, you should be able to reach the set boost level faster when you floor it and also have some level of boost increase. If you would change that hose from 6mm to 2mm, your boost would also increase.

#3. If you change the hose to and fro the solinoid to someting smaller than 4mm, your boost will drop as the air bleed would be slower.

Guys, correct me if my understandings are wrong.

P/S: I know the standard boost gauge is inaccurate especially when it is closing to the 1kg/mm2 mark.

[Richie33]

Seriously, can someone proof read and edit the original post! Its silly the amount of contradicting references to the white/black wires.

- "Cut the black wire" (BLACK)

- "Be sure not to the modify the black one" (WHITE)

- "Basically the white wire goes to your new ground" (WHITE)

- "the white wire doesn't change." (BLACK)

- "tape up the loose end of the black wire" (BLACK)

Look, I know the black wire needs to be earthed but the original post should really be sorted out.

[petern]

I did this little mod on the weekend and the new feel to the car makes it worthwhile.

I went for the on/on switch option as I too don't like the idea of the solenoid/ecu being "on" all the time.

I had troubles trying to find a hole through all the sound deadener stuff on the firewall so I decide to cut the wire at the ECU. Looked like someone already did a bit of splicing

I cut the green wired after someone mentioned it in this thread, but also that it matched the colour in the engine bay going to the solenoid.

I though these might help someone.

[Shakkagts-t]

Hi can anyone tell me if this mod works on the R32, Ive a 1990 GTS-t with the RB20det and an auto box running 10-11psi on full boost (according to aftermarket gauge) with full 3.5inch exhaust from the turbo including downpipe and de-cat and a pod filter. Sounds like a great mod but dont want to fry anything also is the solanoid in the same place on the R32. Thanx

Edited May 23, 2007 by Shakkagts-t