How much boost to run on a sc14 4agze

[wasfishing]

Hey guys,
My aw11 is currently having a sc14 installed aswell as 2.5inch intercooler piping and a W2A intercooler, my question is how much boost should i run through it? apparently stock setup should run about 10psi, i hav an option to buy 158mm crank pulley and boost it up to about 13psi or i could go all out and find a 164mm crank pulley and run 17psi (i like that idea alot ) only problem i'm having now is to convince myself its safe to do? keepin in mind this is my daily aswell as my weekender and sees abit of track work which option would u go?

look forward to see opinions



Cheers Shane

[GUN METAL]

Shane, you wont have any problem running like 20 PSI through the intercooler.

If the SC is going to like running that much boost or if the ECU is going to deal with it and the change in air mass is an entirely different matter.

thats why i was keen to see what boost you actually end up with with a certain pulley ratio.

From what i have read upto 13 PSI should be ok but i think you might be pushing your luck / engine life much past that.

The other thing to consider is the higher you go the more losses you get on the water pump and general efficiency of the SC.


I would start conservative and see what boost you get stock first. Then go from there

Its not difficult to put a larger pulley on later.

Just my 2 cents

Edit i think yor server at work doesnt like me, my to last emails have bounced

I will do some cutting and pasting in a moment

[GUN METAL]

so why wouldnt u run more than 13psi? isnt feral, adz and OMY running around 17 on stocko motors?

STOCK MOTORS MAYBE BUT ADS HAS AFTERMARKET ECU, DON’T KNOW HOW FREALS WAS SET UP AND OMY HASN’T HAD IT RUNNING FOR LONG AT ALL. SIMPLY THE MORE BOOST YOU RUN THE HIGHER THE RISK OF FAILURE. IF IT WAS ONLY ON THE ROAD AND THE OCCASIONAL TRAFFIC LIGHT DERBY THAT’S FINE, BUT ON THE TRACK YOU HAVE WOT FOR EXTENDED PERIODS OF TIME, HELL THE STOCK ENGINE WOULD PROBLY HANDLE 30 PSI IF IT WAS FUELLED CORRECTLY ITS JUST HOW LONG IT WILL LAST THAT’S THE ISSUE, REMEMBER IT ISNT EXACTLY A NEW ENGINE EITHER RIGHT ??


wat do you mean the differance between 10 and 13 is marginal? doesnt really feel much different?

THATS RIGHT IT DIDN’T FEEL THAT MUCH DIFFERENT AND ONLY MADE A FEW MORE MAX KW IT DID PULL A BIT BETTER MID RANGE BUT WAS VERY MARGINAL

AT THE END OF THE DAY I AM ALL FOR MAX BOOST BUT I DONT WANT TO SEE YOUR ENGINE DESTROY ITSELF THE FIRT TIME YOU DRIVE IT.

i KNOW THEY RUN VREY RICH WITH FACTORY FUELING ON STANDARD BOOST SO IT WILL PROBLY BE OK, I JUST DONT WANT TO TAKE RESPONSIBILTY FOR IT HENCE MY CONSERVATIVE THOUGHTS

[wasfishing]

no need to yell scott lol

will also be running bigger injectors lol will see how it goes stock first

[Duk]

I highly recomend a bigger throttle body.
The standard 1 is too small for the stock SC12 with stock pulleys.

[Adsport]

i only ever ran 13psi with stock management and 440's . dyno AFR readout was pretty on the button so i was never keen to push it more until i could fiddle with the fuelling.

in regards to feral running 17psi , 17psi from an SC12 is only a percentage of the volume of air an SC14 would push at 17psi so i think that should be factored into it. i think 13psi from an SC14 would be similar to the volume that an SC12 would push at 17psi (educated speculation) but with a lot more density and less temperature.

[Duk]

I pump 7psi worth of turbo air into my standard pulley SC12 (don't know what the engine is seeing ) and the standard computer and injectors are supplying enough for a full load 12.5:1 AFR (Innovate LM1)

[TERRA Operative]

4AGE throttle body, water pump under drive pulley (Nate tune have a nice one) and no more than 18 pound MAX (or you'll kill the charger).

[GUN METAL]

wasfishing, you got it going yet ? Tell us the pulley sizes and the resulting boost.

Plonka, sounds interesting, what turbo you running and what sort of power, you got a dyno you can post or performance figures please. also can you give me some info on the throttle body mods, i am pretty sure mine is factory AE101, what size are they ?

[Duk]

Plonka, sounds interesting, what turbo you running and what sort of power, you got a dyno you can post or performance figures please. also can you give me some info on the throttle body mods, i am pretty sure mine is factory AE101, what size are they ?

Turbo is a Mitsubishi TD06, but that's only temporary. A new tubular manifold is also on the wish list to replace the log 1 I built.
It hasn't seen a dyno, so power is unknown.
Standard GZE throttle body bore is 50mm. Standard 4AGE throttle body has a 55mm bore.
A standard GZE TB has enough meat to be bored out to 55mm.
A standard GE TB has enough meat to be bored out to 60mm.
With a standard TB, my GZE MR2 engine would pull 4"mercury (nearly 2psi) vacuum between the TB and supercharger above 6400rpm. That's with standard pulleys too.
The cast pipe that the TB bolts to has a rough internal finish but is actually more like 55mm in diameter and is only smaller at the TB flange.
A GE TB bored out to 60mm should be a minor improvement again, as the extra surface area is roughly equal to the area taken up by the TB shaft. ie, it's like having a 55mm TB without any shaft through the TB.

[TERRA Operative]

Check out the AE101 link in my sig for a full walk through on how to adapt a 4AGE throttle body to a 4AGZE...