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HOWTO: RB25DET High Boost mode with standard solenoid


paulr33

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I just did this nifty little mod on the weekend in my R33 GTS25t. Sweeeeeet.

Used the wire through the plug method as in post 231 page 12 and 571 page 29...

except I put a switch in my centre console where the snow/power switch was.

(Used to be Auto but was converted to manual in Japan).

I just use it for that ocassional extra kick in the pants.:w00t:

Being pretty new to Skyline ownership, I find the extra little bit of boost is just fine for the moment.

I did read on another forum someone suggested using 2 stock boost solenoids might up the boost by an extra 2 psi. Would this work?

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When I first did this it was good for a day... excellent in fact. Up to 4500rpm it runs way better.... then after that its CRAP. Going to try tape/silicone the plug leads and replace the plugs on Tuesday/Wednesday... but tomorrow im putting it back to normal. After 4000rpm there is very little there until 6000rpm when it feels like the power comes back on.

I'd say I need an SAFC to do this properly?

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Been running this for a while with a switch wired in. I've decided to switch back for a while though because my Turbo bearings are starting to whine so the turbo is going to die soonish. Make of that what you will.

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I'd like two stage boost... but at 5-7/10psi. Unfortunately Im going to install an RB20 actuator and have to keep my foot off it at 10psi. What effect would an RB20 actuator and 10psi gate have on the two stage boost? Will it run something-psi/10psi two stage? I figure Ill have to just remove it altogether... or leave it as it is now.

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I'd like two stage boost... but at 5-7/10psi. Unfortunately Im going to install an RB20 actuator and have to keep my foot off it at 10psi. What effect would an RB20 actuator and 10psi gate have on the two stage boost? Will it run something-psi/10psi two stage? I figure Ill have to just remove it altogether... or leave it as it is now.

I tried leaving the two stage boost in-place with a 10psi actuator just to see how it would act (a long hope of 10psi bleeding into 12psi).

Unfortunately it runs closer to 10psi bleeding into 14-15psi... not good. That could probably be adjusted down if you got into the right maps via a nistune so the solenoid wasn't so open, but yeah. I've left mine disconnected for a solid 10psi all the time. Runs beautifully.

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So there isn't going to be issues with fuel maps or anything when upping the boost to 7/7psi or 10psi? Since I upped the boost the higher rev range is just crap... but I have to change my spark plugs and regap them and then probably silicone up the coil leads to make sure that isn't the problem. Mostly does it worse when it's hot. Going to remove the middle plug cover also for better cooling of that section. Will get another chrome one laser cut with some funky gfx I make in photoshop =)

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So there isn't going to be issues with fuel maps or anything when upping the boost to 7/7psi or 10psi? Since I upped the boost the higher rev range is just crap... but I have to change my spark plugs and regap them and then probably silicone up the coil leads to make sure that isn't the problem. Mostly does it worse when it's hot. Going to remove the middle plug cover also for better cooling of that section. Will get another chrome one laser cut with some funky gfx I make in photoshop =)

I've had no problems with mine on 10psi - it's an R34 though - each car is going to be different, I imagine.

It's a hell of a lot better kick in the pants than a pure 7psi (ie: locked high boost mode) and it holds the boost more consistently through the rev range.

Sounds to me like you have some sort of ignition break down. Plugs are one fix, but if it does fix it - likely that you just need to replace your coils. Yellowjackets are dead cheap - cheap insurance. I changed mine with the recent 100,000km service, despite the original Nissan ones working perfect.

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Well in the past month I've bought an R33 GTS-T, VT250F motorbike and a new helmet so I am pretty broke till next fortnight.

It's really crap after 4000rpm so I might just use the wasted spark DIY thread and get a VN coilpack setup.... tomorrow after work I'll pull the plugs and regap them to 0.8mm, and silicone around the coilpacks to ensure they aren't having problems from cracks. Ill test that out and then if it doesn't work Saturday Ill do the VN coilpack setup.

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Im getting under 300km's to a tank.... last tank I got 320km's because I babied it a bit... all I got is 3" catback and K&N filter. I filled up 57 litres today @ 1.50 of BP98 and cost me $88..

$88 for 60L for 300km's? - 20L/100km? and its not even that fast... my NA worked EB falcon will beat it nasty off the line and its only 157kw+ 350Nm or so. Plus falcon does 530km's off a tank. Really considering getting rid of the skyline because its eating into my wallet in petrol big time!

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Im getting under 300km's to a tank.... last tank I got 320km's because I babied it a bit... all I got is 3" catback and K&N filter. I filled up 57 litres today @ 1.50 of BP98 and cost me $88..

$88 for 60L for 300km's? - 20L/100km? and its not even that fast... my NA worked EB falcon will beat it nasty off the line and its only 157kw+ 350Nm or so. Plus falcon does 530km's off a tank. Really considering getting rid of the skyline because its eating into my wallet in petrol big time!

Wow that is high. i drive mine relativley hard and get 400km minimum. I know of people getting closer to 500. Mine only has a cat back exhaust and is in need of a service( which is happening this week) so i am expecting it to get better after that.

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When I did the solenoid mod it had nothing at 4-5000rpm so maybe it will pay for me to pull the plugs out and regap them and silicone the coil packs or change it to a VN one and run wasted spark. I sourced a VN coilpack for $20 and have a set of Eagle 9mm leads on my Falcon I could use. I just filled the tank yesterday and put the boost back to 5/7psi. I figured I would really need an SAFC, I seen dyno graphs of stock Skylines and how rich they run when they are working right on factory ECU, must be nasty when there is spark breakdown and thats where my fuel consumption is going out of the window.

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I've done 200km's and the needle hasn't come off full yet... wtf? I'd say Im having issues with the spark because even at 4500-5500rpm its very very slightly noticeably bogging down and then going full steam again at 6000-6400rpm.

your fuel consumption could also be 02 sensor related, i just recently changed mine, and i get round 400-450km out of a tank and thats driving in city traffic in a rb25det. also be careful with the waste spark alternative, as they can be hit and miss whether they actually work.

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I got 420km's from 55L with it back to standard... I can tell the spark is breaking down and the car is running really rich, so with the coilpacks fixed and a SAFC tuned it should be pretty economical after that. I guess I'll start with the silicone/tape method now and then turn the boost back up and see how it goes.

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  • 1 month later...

Just wondering, Has anyone had any solenoid problems running this boost mod without a switch from around 2004-07 to now?

Hey mate have you had the car long? Looks like exactly like Rene's previous car.

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  • 1 month later...

Hey Folks

New to the world of Skylines, and I have tried this modification but im still getting .5 till 4,600rpm and .7 after.

I have cut the black wire, added an earth wire and bolted it to the car. I have done this in 3 different holes and none seem to work, car still hits .5 and boosts to .7after 4600rpm

Any help, should i just keep trying different bolt holes etc??

Cheers

Magoo

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