increasing boost in my gt legacy

[Guest]

How do i do this, and my engine makes a tapping noise,comes and goes every now and then, i brought some lifter cleaner stuff kind of worked but now it seems to have a faint tapping/knocking sound continuisly, maybe its in need of an oil change too, will this help, and what kind of oil do i use? cheers

[Guest]

There are various ways to raise the boost, it depends on how much you want to spend and what your trying to achieve. As for the lifter noise, Promar make a product which is quite popular and seems to work. I think from memory it is called MBL8 or something, but someone will correct me if this is wrong. Which oil? another source of great debate. I have always used Castrol and have never had any failures both on the road or the racetrack so stick to it, it works for me. Others will have their favorite, its something you need to decide for your self.

[Joker]

Wait you want to increase boost by changing oil?

most use boost tap or EBC...

What year/model GT that covers every model from 1990 to um 2008?

[zarnah]

my advice (assuming your gt is a gen 1) is keep it under 12psi unless you have the supporting mods to support more, learnt that as a younger man winding boost up to 15-16psi with no suporting mods, would detonate and miss like hell and cost me about 3 engines before I finally started listening to the mechanics. These days I stick to the 12psi rule, I dont really see the point other than straight line grunt for excesive amounts of boost, take your car around a windy track running 12psi and see if you can "outdrive" the boost you're running....

[DRFVDR]

and for my 2c worth

your engine is making tapping/ticking/unusual noises and u want to increase the boost on it....

I would not even consider it until i have fixed the problem.Yes it may be noisy tappets but it could also be other more serious things,get it fixed before u increase your boost.....

What other mods have you done...

with out supporting mods increasing boost wont really do much

your mod trail should look something like this. Exhaust make it free flowing as much as u can,intake clean it up make it breath,then boost.....

Also maybe look at brakes as making it go faster is all good but making it stop and handle better makes it quicker....

[wildturkey]

pretty much agree with everything that's been said but if ur hellbent on winding up the boost then ur biggest bang for buck mod is a boost tap. That should put u in the 12psi range (assuming ur engine is ok in the first place). once u get past 12 or so psi u might start getn boost cut which I believe is the factory map sensor fail safe telling you to turn down or detonate! In any event the factory settings won't let u run it over a certain psi. To go beyond 12 psi safely u will need other supporting mods and it can get pricey!..........and once u start it's soooo hard to stop :-) Good luck

[G-unit]

just took my tap off,running 7-8psi now,half bar, kinda suks tap will be back on 2moro, still under 1 bar, hate bar gauges, thinks its 12psi im at anyway, and hesitates but thinking now that its a bad injector or afm

[Guest Oscar]

 zarnah said:

my advice (assuming your gt is a gen 1) is keep it under 12psi unless you have the supporting mods to support more, learnt that as a younger man winding boost up to 15-16psi with no suporting mods, would detonate and miss like hell and cost me about 3 engines before I finally started listening to the mechanics. These days I stick to the 12psi rule, I dont really see the point other than straight line grunt for excesive amounts of boost, take your car around a windy track running 12psi and see if you can "outdrive" the boost you're running....

Interesting about the 12psi rule. I wasn't having any issues at 14psi, but then every engine is different. With that in mind, stick with the 12 psi rule.

It's also depending on the state of the fuel pump and the injectors and also the quality of the fuel.

[G-unit]

 Oscar']

[quote name='zarnah said:

my advice (assuming your gt is a gen 1) is keep it under 12psi unless you have the supporting mods to support more, learnt that as a younger man winding boost up to 15-16psi with no suporting mods, would detonate and miss like hell and cost me about 3 engines before I finally started listening to the mechanics. These days I stick to the 12psi rule, I dont really see the point other than straight line grunt for excesive amounts of boost, take your car around a windy track running 12psi and see if you can "outdrive" the boost you're running....

/quote]

Interesting about the 12psi rule. I wasn't having any issues at 14psi, but then every engine is different. With that in mind, stick with the 12 psi rule.

It's also depending on the state of the fuel pump and the injectors and also the quality of the fuel.

thats why my injectors are getting checked on wednesday and we only get 95 octane in my town

[zarnah]

yea just because you "think" you're not having any issues at 14 psi doesnt necesarily mean that your'e not, 12 psi is just a safe number

[Guest BLST!C]

Say you plan to ignore the noises made and want to raise the boost anyway.

I got 1.5 (ish) psi by removing the hose from between the resonator chamber and the boost control solenoid. I blocked the port on the resonator.

The next cheapest is to insert a multi-turn tap valve between the compressor outlet and the boost control solenoid. Closed = free-boost. Open = stock. Infinitely variable between the two.

That was on a 1st gen legacy

[Guest]

I think the prev owner did that to mine need to get it back to std as i dont like the 16psi boostcut engine shutdowns

 BLST!C said:

Say you plan to ignore the noises made and want to raise the boost anyway.

I got 1.5 (ish) psi by removing the hose from between the resonator chamber and the boost control solenoid. I blocked the port on the resonator.

The next cheapest is to insert a multi-turn tap valve between the compressor outlet and the boost control solenoid. Closed = free-boost. Open = stock. Infinitely variable between the two.

That was on a 1st gen legacy

[G-unit]

my car feels so much better on 7-8psi now,also not as laggy, will run 10psi if put tap in later on

[Guest Oscar]

 BLST!C said:

Say you plan to ignore the noises made and want to raise the boost anyway.

I got 1.5 (ish) psi by removing the hose from between the resonator chamber and the boost control solenoid. I blocked the port on the resonator.

The next cheapest is to insert a multi-turn tap valve between the compressor outlet and the boost control solenoid. Closed = free-boost. Open = stock. Infinitely variable between the two.

That was on a 1st gen legacy

110% fail right there. All it's going to do is make the BCS work harder to get it to stock levels. The whole point of a MBC is to eliminate the BCS entirely. Also freeboosting is not fun.

[G-unit]

theres a manual psi tap in here 4sale cheap, easy 2 hook up, remember 2 avoid stock controller when puting in a different 1

[BLSTIC]

Actually oscar, this can and does work on open loop boost control systems such as the first generation legacies and pre-bugeye WRX's.

What it does is make the bleed more effective (the solenoid is an electronically controlled bleed).

The closed loop boost controllers on V7 (I think) upwards need either re-programming or replaement, there's no way around that one... They will just lower the duty cycle (and bleed off less air) in response.

And yes I did try it on my own 1st gen legacy. It worked, but the valve I used was too coarse (not enough turns between open and shut) And 1/8th of a turn was about 5 psi... A different valve would have been great.

[Guest Oscar]

Well I tried it once too, and discovered that it didn't work. When it was partly open, all that would happen would be a short spike to Xpsi, and then it would just taper back down to the factory 9psi. It doesn't give proper control over boost as all it does is give you an increase in boost and then the BCS would overcome the tap and then everything will revert back to normal levels. The only way to have complete control is to bypass the BCS entirely and hook up the tap so it is connected to the turbo and wastegate directly. To keep the ECU happy, leave the BCS plugged in.

So please, stop spreading misinformation.

BTW, boost cut is at 16psi, so there isn't much to be had in freeboosting on a gen1 with a factory ECU.

[BLSTIC]

Well I know it worked fine for me, aside from having a valve that was too coarse. I adjusted the boost from 10psi (after removing the hose between the solenoid and the air intake, because it had a small restrictor pil in it for some reason, and I wanted more boost, it was at 8.5-9 stock) to the boost cut at 15, and anywhere in the small range between. I could get it to hold 14psi for 5 seconds (before I ran out of road or had to change gears) at full load.

Did you have the valve in the line between the compressor outlet and the solenoid, or between the solenoid and the wastegate? If it was between the solenoid and wastegate all it will do is delay the pressure from getting to the wastegate, rather than making the bleed more effective, causing the symptoms you had.

Alternatively you have closed loop boost control, what car do you have?

The boost controller I have now is effectively a check valve with adjustable preload and a fixed bleed. The solenoid has been disconnected. Aside from the fact that it uses different sized plumbing and the boost curve isn't completely flat (ie 15psi at 3000rpm if I load it up uphill or in 4th gear, down to 12psi at 5500) I couldn't be happier with it. The only reason I didn't buy another (finer) tap valve was because I already had this 'pressure reducing valve' lying around for another project that I stopped working on.

I got the idea from an autospeed article, I'll try find it.

[Guest Oscar]

 BLSTIC said:

Well I know it worked fine for me, aside from having a valve that was too coarse. I adjusted the boost from 10psi (after removing the hose between the solenoid and the air intake, because it had a small restrictor pil in it for some reason, and I wanted more boost, it was at 8.5-9 stock) to the boost cut at 15, and anywhere in the small range between. I could get it to hold 14psi for 5 seconds (before I ran out of road or had to change gears) at full load.

Did you have the valve in the line between the compressor outlet and the solenoid, or between the solenoid and the wastegate? If it was between the solenoid and wastegate all it will do is delay the pressure from getting to the wastegate, rather than making the bleed more effective, causing the symptoms you had.

Alternatively you have closed loop boost control, what car do you have?

The boost controller I have now is effectively a check valve with adjustable preload and a fixed bleed. The solenoid has been disconnected. Aside from the fact that it uses different sized plumbing and the boost curve isn't completely flat (ie 15psi at 3000rpm if I load it up uphill or in 4th gear, down to 12psi at 5500) I couldn't be happier with it. The only reason I didn't buy another (finer) tap valve was because I already had this 'pressure reducing valve' lying around for another project that I stopped working on.

I got the idea from an autospeed article, I'll try find it.

I tried putting the valve in both possible locations, between the solenoid/wastegate and also between the solenoid/turbo and neither had proper control over it. It was at the time a BF-5 GT. The best way is to just run the valve between the turbo and the wastegate. It eliminates the solenoid entirely.

But when I get my BC5 RA functional I doubt I'll be playing with boost levels at anytime soon. I got a chipped ECU to have fun with.

[BLSTIC]

If you do use just the valve between the compressor and the wastegate don't forget about a bleed.

Since when was there a 1st generation RA?

[BC5RA]

 BLSTIC said:

If you do use just the valve between the compressor and the wastegate don't forget about a bleed.

Since when was there a 1st generation RA?

http://www.autospeed.co.nz/cms/A_1905/article.html Heres the article previously mentioned.

Since when was there a Gen 1 RA? since 1989 not only that but technically speaking they are also an STI (albeit in a lower tech form) as a very early form of STI worked on the engines powering these.

[G-unit]

im sure my stock unit has a pill type thing in it,should i remove it for bit more stock psi?

[BC5RA]

Just leave it, Gunit.

[Guest]

This is how my BoV was installed, i got spare piped that are just blocked off..

after reading this i think this could be the reason im overboosting...... could it?

[G-unit]

will do

the bov looks like how mine was done in my TT but less pipe lengh