Max boost Plz help i dont wanna cook my engine!!!

[Lunchie]

Hey guys im thinking of upping the boost on my 1990 subaru gt and im wanting to know a safe limit. The current level is 9-10 with spikes of up to 12 for a millisecond on gear changes (its an auto)

From what ive read 15psi seems to be the safe limit but im not so sure. "speed mag" reccomends 15psi as the limit for wrx's in their tuning guide so i presume the same would apply for my engine since the differences between early wrx and legacy engines were very small.

My current idea is to purchase a "gizzmo" chip from turbo shop which remaps the fuel map and raises boost to approx 12psi ( so max boost would be about 14 psi for a fraction of a sec when my shit auto box changes). What do u guys think? is this a safe level for sustained reliability?

I know its not a toyota but there are sum really smart guys in here so id love to hear from you.

[craigt]

Just be aware that when those turbos come apart they do it in style.
Not designed for big boost

[Dell'Orto]

Single turbo joker eh? I wouldnt recommend more than 12psi, just to keep things safe. They use a VF8 (or is it the 10? Cant never remember), which is fairly small (smaller than the manual ones anyway).

[pervert]

12psi sounds about max, but if you really have to up it, don't go past 14psi, just to be on the semi-safe side.

Forget the Gizzmo idea, they are good chips, but when it comes to Subaru's you can do much better. Subaru NZ have a good range of piggyback chips available for your style Subie, just talk to them. The price range is fairly similar to Gizzmo, but Subaru making chips for Subaru's should mean better results.

Especially when it ditches that speed cut...

[CozmoNz]

are they ceramic turbines? BAHA! eat it!

yay for the steelies .

lunchie, like i said, go get yourself a BIGGER turbine.. trust me, youd love it.

wrx's old turbo's arnt that expensive..... and im sure either it will bolt stright up, or a $50 weld on job @ the exhaust shop for a new flange...


and your bling bling downpipe will fit .

if your feeling rich go buy a performance ej20 exhaust manifold... at only $800 its cheap at twice the price.. yeh right... fuking flat engines

im not completely sure, excactly how much but they are bloody expensive anyway .

but like i said, bigger turbo, same boost, more high end.. youll love it... .

[Volatile]

My brother has a legacy wagon single turbo manaul

don't put a boost tap in it!! only raise the boost by aftermarket chip

he's been running 15-18ish psi i think for over a year with no problems but he's running a TD05 of a wrx sti

[pervert]

The chips make a huge difference in the Subies, you WILL notice a difference, they might even be able to give you actual fact based difference if you ask them too.

[Dell'Orto]

My brother has a legacy wagon single turbo manaul

don't put a boost tap in it!! only raise the boost by aftermarket chip

he's been running 15-18ish psi i think for over a year with no problems but he's running a TD05 of a wrx sti

Even at 18psi, Im surprised it hasnt done nasty things to itself...the turbo will be able to handle those sorts of boost pressures fine, but the fuel system will be near maxing out.
A friend of mine had an RS with the TD05, PossumLink etc etc, and it nuked many a gearbox running 18psi, and then eventually the motor spat the dummy. A chip or aftermarket computer wont make an injector push more than it can physically flow.

[RS13]

I wouldn't mod an auto Subaru, those gearboxes are very well known to let go, even with a factory setup. If you really liked the car, and intend to keep it for a long, long time, it'd be worth getting a manual conversion, using a 5spd from a twin turbo, as those things are much better engineered over the earlier 4wd gearboxes, and can handle a LOT of punishment. Just make sure you get a decent clutch, cos doing a clutch in a Subaru is a PAIN IN THE ARSE!

But.. yeah, if you're going to raise the boost in any car, it ALWAYS pays to get the rest of the car up to scratch, so you don't get any broken bits and pieces, ruining a good night out!

[Lunchie]

thanks guys i think ill go with the gizzmo chip which im having programmed to run at 12 psi. Mike lyn at turbo shop told me it should stay at 12 most of the time although there may be fluctuations during gear changes of 2-3 psi.
So basically it wont even get above 15 and even then it will only be that high for a fraction of a second. Ill get back to you with the results

Thanks for the help

[1598cc]

are they ceramic turbines? BAHA! eat it!

yay for the steelies .

lunchie, like i said, go get yourself a BIGGER turbine.. trust me, youd love it.

wrx's old turbo's arnt that expensive..... and im sure either it will bolt stright up, or a $50 weld on job @ the exhaust shop for a new flange...


and your bling bling downpipe will fit .

if your feeling rich go buy a performance ej20 exhaust manifold... at only $800 its cheap at twice the price.. yeh right... fuking flat engines

im not completely sure, excactly how much but they are bloody expensive anyway .

but like i said, bigger turbo, same boost, more high end.. youll love it... .

Sadly, itd never be 50 bucks for that at an exhaust shop..

[Dr-X]

I wouldnt be paying more than $50, I'm not sure what exhaust shops you go to.