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HOWTO: RB25DET High Boost mode with standard solenoid


paulr33

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u might wana read over the 11 pages again :P

not sure what the big issuel is.... cut the black wire... connect it to a bolt so its grounded...

put foot on accelerator... watch us gauge shows 7psi before you get to 4500rpm.....

I guess it wont work in *everyones* car but from what i've read in the last 11 pages.. looks like its worked on 90% of them...

Would it still work if you splice into the wire like a T.. or do you actually have to cut it ?

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try hook it upto a differant bolt ??

I dont know squat about electronics etc, but when i was trying to ground something else on the bolts near the gearstick inside the car, i found a few of them didnt work as a ground very well..

another thing to test.. try disconect the black wire completly and just make sure the boost never goes over 5psi.. (evan at over 4500rpm)

justin i'm not saying it is hard to do. Shit it's only a 2 min job all i'm saying is i can't notice any difference
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It works fine for me and I notice quite a difference. Try this. Get on a Freeway in 3rd gear. Get it on full boost at 3000RPM, then flick the switch. Sounds Crazy!!!

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Is it possible for this to work if you just bypass the control valve all together.

EG.

It has one pipe going in and one out. If you just take them both off and join together. Wouldnt that to the same affect????

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Guys this trick really does work, it makes a hell of a difference.

Just look at the Dyno sheets i was given after my mechanic did it.

It was on the dyno as he was tuning my SAFC but he noticed this mod hadnt been made so he took the liberty of doing it with dyno curves before and after.

Red line is before SAFC (Ignore)

Green line is after SAFC tune

Blue line is after boost controller mod

Gain of 200NM of torque, a shift in the power curve to the left, and boost comes on heaps earlier.

JUST DO IT!

post-23179-1143511011.jpg

post-23179-1143511038.jpg

post-23179-1143511060.jpg

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There is another way to do this with exactly the same results. The only difference being that it is not visable inside the engine bay, or if wanting to use a switch can be done from inside the cabin. ( no running wires through the firewall)

Items required

wire ( different colors prefered)

Spade conectors

12 v 30amp changeover relay

on/off switch

Tools required

- wire cutters

- wire crimpers

Time taken about 30 min

This involves cutting wores directly from the ecu located in the passenger kickpanle. if you are not able to, or are not sure of which wire to cut, DONT do this!

1 - Remove passenger kickpanel

2 - on ECU locate plug second from bottom ( while it is still mounted in car)

3 - locate light green wire coming from this plug.

4 - cut wire

5 - install relay

Wiring for relay is:

30 - to green wire car side

87a - to green wire ECU side

87 - to pin 86 on this relay

85 - accessory 12v

86 - switch

6 - install switch

Wiring for on/off switch

pin 1 - to pin 86 of relay

pin 2 - earth

7 - reassemble car

8 - test drive

When the switch is in th ON position you will have high boost mode all the time, when the switch is off, it will run as a standard car ( hi/low boost mode)

Notes:

- Test car was a R33 series 2 - check wiring colors on other models before proceding

- Make sure all electrical connections are insulated

- make sure that all wiring is secured and cannot be damaged by normal operation of the car

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Did this Mod.. worked like a charm.... the Car suddenly Came Alive hehe..

Anyways.. can u guys show me a pic of what you did or instruction.. on how u made a switch to turn the mod On and Off.. and another Thing

When i put my foot down, the needle on my Stock boost Gauge goes up to 3/4 or just little bit above that towards the full 1 Bar. So what PSI is my Car running on at the moment.?? only had my car for like a month.

P.S. ( I have HKS Filter and Full 3 Inch Turbo Back wif 4 1/2 inch Tip)

Cheers

SeSaR

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Cost effective and easy way to leave the current setup (ECU grounds controller @4.5K) and have an override switch in the system, Is to place a diode inline with the ECU switched ground (0v) and the switch after the diode (see Pic). The diode will let the 0v from the ECU through but will block the 0v from the switch going back into the ECU.

(Warning! Diodes are directional, placed in this circuit the wrong way around will harm nothing but it will mean that the switch when on will send 0v to the ECU and when the switch is off the 4.5K rpm ECU output will not pass through the diode)

post-27968-1144543058.jpg

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Why bother with all this passive relay / regualr relay stuff? A simple 3 way switch(PTT) will do just as good a job?

waiting for someone to shoot me down.....

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  • 2 weeks later...

Ok I did it today, I've attached pics to show my wiring. The car to me feels like it's got more urgency through the rev range now. I've also attached a pic showing where my stock needle goes to, it does this straight away and holds there. Can anyone confirm that this is the right place for the high 7-8psi factory setting as it's been a while since I booted it and could just be mistaking the feeling of power for standard 4-5psi.

Cheers

PICS!

post-23873-1145591985.jpg

We soldered this and then taped it up.

post-23873-1145592054.jpg

Then we rubbed some paint off and bolted our earth to the chassis.

post-23873-1145592106.jpg

Here you can see how it all looks, pretty tidy.

post-23873-1145592140.jpg

And this is where my needle sits now...

post-23873-1145592181.jpg

Hope that helps someone, now can anyone confirm that this is the right place for the needle to be sitting.

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very neat dan....

dont quote me, but i thought the wire had to be cut, not just tapped into like you've done?

I may be wrong, but thats how I thought it HAD to be done to work...

and your gauge is sitting on maximum vac....so that really has nothing to do with the high boost mod as far as i know

but at stock high boost the needle should be on or just above the middle slash on the boost side of the gauge....

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if thats where its sitting on full boost BELOW 4500RPM, id say its working fine....thats about where mine sits....

my car showed 8.4-8.5 the whole way on the dyno run...and my aftermarket gauge shows 8psi....and my stock needle is about where urs is in that pic :pwned:

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