Lower Pressure Boost Control

[pipster11]

hey guys

currently running 5-7psi on the stock turbo (rb25neo in a manual stagea)

just wondering if anyone has recommendations for my current situation.

I run 5psi most of the time and leave it set to that, my gf takes the car to uni a bit and i actually like to run it on lower boost and use more throttle and the natural torque of the engine

but at 7psi it was only dynoed at about 135awkw a couple of years ago (previous owner)

i want some more go and was thinking of taking the boost up to 10 or 12 psi

there is an eboost street going for about $250 locally to me that i was thinking about

or can i solder and redrill the restrictor out to allow more air to bleed off?

what do you think the best option is?

i'm also thinking about getting a nistune come summer, hence not wanting to run 10-12psi all the time

Thanks, Tom

[Bsa]

just get a bleed valve i bought one for 25 dollars and works a treat just make sure you have a aftermarket boost guage to set off. 10 should be fine i would do more mods before tune rather then everytime you make a change you need a tune but thats my opinion

[89CAL]

turbotech (?) boost tee off ebay, $20 and there are many people that swear by them

[T04GTR]

bleed valve.

[Room42]

Drumroll.....................Bleed valve! And attach a friggin huge spring to the outside of the actuator for quicker spool.

[pipster11]

yeah but i want to be able to run 2 pressures

one for me, one for everyone else

[Odium]

yeah but i want to be able to run 2 pressures

one for me, one for everyone else

How do you want to be able to switch between these two pressures?

With the Bleed Valve you can work out your two points (5 and 10) and put markings on the bolt where it needs to be screwed in to for each setting.

Simple pop of the bonnet, unwind the screw until the mark, and you're on your new boost setting. Always go easy and keep and eye on the gauge for the first run after you adjust, to protect against overboosting.

Switching between two levels of boost on a daily basis wouldn't be a great option in my opinion though...

The Engine doesn't run as amazing as it could after a change in boost, you need to get it to relearn (disconnect battery to drain power from the system and reset the ECU) and adjust its maps a little bit to accommodate.

My ECU relearning experience comes from an RB25DET in a S2 33 GTST, so your results may vary...

Its possible, but not recommended imho.

[chuckie]

jaycare ebc

,http://www.skylinesaustralia.com/forums/topic/375223-jaycar-iebc/

[kosmo90]

how about doing the earthing mod to the solenoid and putting a switch in the car?

Sorry just reread the first post, scratch that idea.

Edited October 13, 2011 by kosmo90

[pipster11]

how about doing the earthing mod to the solenoid and putting a switch in the car?

Sorry just reread the first post, scratch that idea.

sorry, i should have said, thats the method im using at the moment

its acutally a down grade for an rs4s as the stock ecu runs at 7 all the time, so my setup lets me force it down to 5 psi

i'll be driving from tas to qld again in about a month and its pretty good on the highway like that because on a big hill you can bury your foot and only use 5psi and the natural torque, this would also keep the air flow down and therefore stay on a leaner section of the fuel map

i might see if i can get the stock setup to bleed off a bit more on high boost with a slightly bigger hole in the stock restricter

[R31Nismoid]

i actually like to run it on lower boost and use more throttle and the natural torque of the engine

So by natural, you mean less – correct?

Because that’s what’s happening. Less boost = less torque. A lot of people that do the "wind down the boost" end up using full throttle everywhere and more RPM for the same cause. It’s a false economy really as more RPM more of the time is undue wear

The best boost controller on the market that I found was the right foot. You want more boost you simply press the foot further into the floor.

Works just the same for economy, you want better economy use less of the right foot. Regardless of if you run 5psi or 20psi the economy will be pretty much the same in off boost situations

[pipster11]

So by natural, you mean less – correct?

Because that's what's happening. Less boost = less torque. A lot of people that do the "wind down the boost" end up using full throttle everywhere and more RPM for the same cause. It's a false economy really as more RPM more of the time is undue wear

The best boost controller on the market that I found was the right foot. You want more boost you simply press the foot further into the floor.

Works just the same for economy, you want better economy use less of the right foot. Regardless of if you run 5psi or 20psi the economy will be pretty much the same in off boost situations

yeah your right but i am not the only one using the car

im also thinking that the stock maps are really rich at high load, more boost = more load, less boost = less load

also the more open the throttle, the turbulence and resistance from the throttle body (pretty negligible thats the theory to the warm air intake thats popular in the states, gives slight fuel consumption improvements due to using less dense air etc, less power, more throttle, less resistance)

also, wouldnt more boost = more load?

so running lower boost on a day to day basis (if you kept the driving style the same) would also be better

[89CAL]

I'll sell you my dual stage turbosmart boost controller. 2 boost settings changed by a switch in the cab. Hide the switch if you dont want anyone touching it.

PM Me if your interested. It worked fine when I was running stock boostish levels

[pipster11]

don't really want to mess around with bleed valves

will be stock or an ebc i think

[zoidbergmerc]

could you have a boost Tee and a 3 port solenoid to by pass it at the flick of a switch to run gate pressure?

That's kind of what I have on mine.

Solenoid off = gate pressure.

Solenoid on = Boost controlled by ECU

but instead of an ECU or EBC doing the work have a TurboTech boost Tee? I had one on my skyline for a bit and still using one on my WRX, they're win.

Could be a cheaper option?

[simark87]

Yeah the Turbotech Original can flow a low psi but the V2 controller can't really go much under 9-10psi.

The 3 port solenoid option in conjunction witha t-pice and a manual gated controller is an easy set that works a treat on most systems. I can help there with a kit if need..

Mark

[KiwiRS4T]

Yours is awd? Just run 12psi all the time. Its not like soemone is going to jump in your car and lose control through spinnng the rears.

[pipster11]

a hypergear rebuild is in the pipeline, just don't want to stress the turbo too much until i can afford to rebuild and tune

which could be a while unfortunately

i was thinking that a boost-t in the solenoid feed line would let me up the base pressure and then flicking the switch would bleed off some more pressure too

but then i'll only get the same rise as before

i've got a jaycar ebc, i just don't like that if the solenoid fails, it fails shut which = infinite boost

[pipster11]

ok, so i've been thinking about it, and had a look on the interwebs

what about a setup like this?

when open, the stock solenoid allows all the pressure to reach the wastegate, when closed the turbotech controls the amount of pressure getting to the wastegate

Thoughts?

[QWK32]

That will work, standard wastegate pressure, 5psi, with solenoid open, bleed valve boost when its closed. But I don't understand the need for dual boost.

Something to think about Tom, no matter what boost level you are running, when you plant the accelerator the ECU uses the last row on the fuel map. You don't see this on a map trace but it does it.

Without checking the table it is at about 3.8 - 3.9v TPS from 3000rpm and only about 2v TPS under that.

So at the lower boost level you are going to chew through unnecessary fuel at full throttle, which I can imagine with only 5psi on stock turbo you are going to do alot lol.