stock boost
 

im about to buy a 1994 supra but its got a boost controller. whats the stock boost on it. also whats the highest i should go on stock components other than exhaust. thanks, i did search just couldnt find anything

Stock boost is about 11.5psi.

The stock components can take as much boost as the oem twins can put out (really!)...BUT (and this is a HUGE "BUT") you MUST run a % of high-octane race fuel (or methanol) above about 14.5psi on 91 octane pump gas in Cali, or 16psi max on 93 octane pump gas in the rest of the US (eg. Florida). If you choose to increase your octane with (for example) c16 race fuel, then you should use at least two full gallons of c16 per tank of 93 octane to run 18psi, and at least 5 gallons (1/3 of a tank) of c16 to run max boost (with some brand-new oem twins you can probably get about 26psi of boost if you push them really hard)...

P.S. If anyone tells you that you can safely run 18psi on pump gas, then ask them if they'll pay for your engine when it blows. If you try to run 18psi on 93 octane pump gas, your engine won't blow right away, but it will start getting damaged, and over the span of several months your compression #s will get worse and worse ... and when you see the whitish smoke constantly coming from your tailpipe you'll find you need a new shortblock when you do a compression test & leakdown. Again, 16psi max on pump gas, unless you run a few GALLONS race fuel or a large 'shot' methanol injection kit. Note that a cup or two of an octane booster offers almost no significant change in motor octane. With the race fuel (or methanol) the stock 2jz-gte internals will take every bit of boost those oem twins can put out, and a LOT more. On pump gas, too much boost will easily destroy both stock internals AND even the most expensive aftermarket/'built' internals.

thanks a lot. thats a lot of good info. i deffinately dont want to be blowing my engine.

Sounds intense. Does that only apply to MK4 or would that apply to the mk3 as well?

I have hurd storys about 20psi in an MK3 running 5 gallons of 104 and the rest 93 Pump shell gas here in vermont...So im not totaly sure...but it sounds beleiable!

Only to the MK4 Turbo with the oem ecu. It might incidentally apply to some other turbo vehicles as well, but I'm 100% sure about these detailed numbers as they apply to this one application. There is one statement that applies to any forced induction vehicle: "On pump gas, too much boost will easily destroy both stock internals AND even the most expensive aftermarket/'built' internals.".