Jump to content
SAU Community

HOWTO: RB25DET High Boost mode with standard solenoid


paulr33

Recommended Posts

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 ?

Link to comment
Share on other sites

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
Link to comment
Share on other sites

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!!!

Link to comment
Share on other sites

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????

Link to comment
Share on other sites

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

Link to comment
Share on other sites

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

Link to comment
Share on other sites

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

Link to comment
Share on other sites

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

Link to comment
Share on other sites

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.....

Link to comment
Share on other sites

  • 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.

Link to comment
Share on other sites

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....

Link to comment
Share on other sites

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:

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • Go to SP mufflers and get the muffler of size you want and make a nice mid muffler. It's about that simple! I have 2x 3.5 Magnaflow straight through Mufflers and while it's pretty loud with the Varex open, it's quiet enough with the Varex closed. You can also buy off the shelf Magnaflow straight through mufflers as well. You also have a turbo to quiet the car down too. Don't overthink it. Buy my extra Magnaflow muffler sitting on a shelf doing nothing (buy it new, ignore this part)
    • Centre-offset muffler under the floor, same as stock. Just....3.5". The change from straight pipe there to centre-offset will mean that you need to remake some of the pipe (add a bend or two).
    • Hey guys. So my R34 GTT has a custom 3.5” exhaust (done by previous owner) with a high flowing cat, and then just a Varex cannon muffler on the back. The car does drone alot and is really loud even on highway driving just cruising, as you can imagine due to the Varex muffler basically being a straight through with the valve open. As much as i love a loud RB, it can be a bit much with no other muffling in line and just driving casually. I wanted to lower the volume output on the exhaust a bit, as well as remove the drone (probably a way to do both at once), and was going to do it all myself as I am a fabricator and have done exhaust work in the past, so the fab work isnt my issue, im just not sure on the right product or type of product to use to get the job done, and i doubt an exhaust shop would be wanting to help me as they wont be making any money from helping me, unless they supplied the product? Anyway any help or guidance in best way to approach this would be awesome   Thanks in advance
    • Meh, whilst the Honda is a "really" good car and has potential if you want to drop coin on, it was uninspiring for me to look at, but, it did serve its purpose and is now in the boys hands, his happy, his girl is happy, as she wasn't to keen on the noisy old Patrol, and most importantly, the Minister for War and Finances is extremely happy that her "little baby boy" (6'2 nugget who is currently training to be a copper, which will make 3 coppers in the immediate "circle of trust") has a well sorted reliable car that doesn't guzzle diesel Me, I'm more than happy with the NC MX5 that I replaced it with, it's a fun little car that I like looking at, like driving, and yes..... I do like the fact that the maintenance and modifications that I have done/will do are plentiful and relatively cheap, well........ while staying naturally aspirated slow that is, and that's all I really need for a fun little daily, I can rev the 5hit out of it rowing through the gears and never really break the speed limit  In saying that wicked word, "modifications", I've already ordered something for some noise and an additional "3 ish" horse powers, or whatever it gives, in the form of a header, and, a new set of "cheapo" BC coilovers that are already sitting in the shed waiting to get put in, I had the same BC's in my old NB and found they were fine for the street, hwy, and the occasional track days I did in it, they have 6kg front and 4kg rear springs which is about 10% stiffer than the stock springs which I found worked well for their price  I've also already been in touch with MX5 Mania in Dural, so once the header is on it will get a ECUTek RaceROM tune there (I cannot rev match for 5hit, and I loved the RaceROM rev match and FFS in my old 86 "RIP") In other, maintenance news, I put some new sparkler plugs in it, and have a new set of DBA Street series pads to put in over the next day or so, I'm running the DBA street series in the SS and Honda and really like them, they work great and are not dusty at all I've also booked in a few days leave over this weekend to give me 4 days weekend do some paint correction and give the leather seats some conditioning and interior some Bissell and steam cleaning OCD lovin', the carpet and interior looks clean, but from my experience with the Bissell IRT carpet, and the steam cleaner IRT trim, looks can be deceiving I've also found that finding a detachable hard top is proving problematic, the main reason why I didn't like the NC initially was the power retractable hard top that I seen them with gave the roof line a weird look, the detachable roof though looks good, and is a same shape as a NA/NB hard top, similar, but unfortunately not the same as it has different fixture point on the front, so fitting a easy to get NA/NB detachable hard top is no bueno New Old cars are fun, cleaning, hunting and playing around brings much joy How are your beasties going? Do you still have the Skyline with the LS???, or Barra??? that you were playing with
×
×
  • Create New...