not really a race story...but...

[Shane Sawatzki]

Today at work i had a turbo supra owner ask me how much boost i was running and when i said 17-18 psi they said not a chance. I said explain?? they said "I have a t3/t4 hybrid turbo and I have trouble getting 15 psi boost" I simply said well you know the talon comes stock intercooled and with more boost than a supra right? lol thoughts?? could she have been right?? my mods are in my sig...i seem to hit what i think is fuel cut in first gear at around 5-6 k rpm the car kinda bucks and seems like it looses all power...but in 2nd and other gears it has all power and the autometer boost gauge shows 17-18 psi. is that a lie?? lol do I have enough supporting mods to produce taht??

[Jamie Oswald]

mark was hittin 20 psi and hes pretty much stock...

[Mark Guthrie]

ya ive been hitting 20 psi for the last couple months found my boost controller was broken, car pulls hard at 15-17 psi anything over that the timing goes out of wack and i get slower

[Mike Schmid]

I'd say there's something wrong with her car.  If Supras are anything like DSMs and she's having trouble making 15psi it's because there's something wrong with her wastegate or boost controller or the wastegate has too big a flapper or is super ported on the wastegate side or something like that.  If she's having trouble tuning the car to run properly at 15+ psi that's a different story and has more to do with injector size, timing, etc. 

[Shane Sawatzki]

so do you think im hittin fuel cut in first then?? im running 94 from chevron and thats all I run...it just seems if I run it really hard in first gear the car bucks and and i loose power fast

[Josh Royle]

ya i think so cause i get the same problem... but i get it in 2nd and 3rd gear... Feels like your car completely dies on u... ya i think it is... It happened to me after i installed my intake piping and 3" Turbo back exhaust.

[John Hartman]

for the 500th and final time, you MAY be running 17 psi but you SHOULD NOT BE!!  turn it down.  your car will go faster.  You don't have the fuel for that and you have no other mods to support it.  Almost certainly you will be knocking. 

As for the supra, its got a problem.  Most likely a boost leak and/or a boost control problem related to the actuator or the controller of the actuator.

Boost pressure is no the end all be all.  If each car was exactly the same(and I mean exactly, not just the same kind with the same mods, but the same level of carbon build up, the same intake air temps, the same fuel pressure, the same fuel, the same amount of crud in the intercooler, the same injector spray pattern, the same pcv action, the same egr action and on and on), and the boost was kept under the knock threshold for that car, then yes, more boost is better.  But once you change any variable, its a whole new ballgame.

ESPECIALLY with different turbos.  A 50 trim Garrett will flow more than a 9b Mitsu at half the pressure.  Her hybrid Garrett will be flowing more air at 14 psi than you are at 18.  For SURE!

Now, on the other side of the coin, once an turbo is at its limits, and the engine is using all the air, it won't hold that boost.  Boost is after all the air that the engine can't use.  I had an example of this on my red Talon with my 14b.  Yes it was ported and worked really well, and held at least 19 psi to redline, and 22 till about 6600 rpm.  Then I put in a good set of cams.  It would only hold 22 psi till about 5600, then fall off to about 17 by redline.  Sometimes only to 15 or so.  This is because the engine was inhaling the rest of it and the turbo can't keep up.

Bottom line.  Turn your friggin boost down until you do 3 things.  1.)  Get a datalogger so you can monitor knock.  2.) Get an upgraded fuel pump and if needed an ajustable regulator. 3.)  Learn how to interpret the datalogs and what does what.  There are several good sites out there on the data.  Go to our "specs, techs and reviews" thread and look at the pertinant ones.

If you can't do these things, pay someone else to.  If you won't do that, then please do not ask us ANY MORE QUESTIONS ABOUT YOUR BOOST, or any other boost related questions. NO ONE CAN HELP YOU until these steps are taken.

Or you can run stock boost and make sure you are running premium fuel and the complete rest of the system is STOCK AND IN WORKING CONDITION.  Then just drive it.

[Mark Guthrie]

lol  this guy still hasnt stopped asking about this lol