what is the max psi i should boost on these mods to keep things "safe" until i can get a better fuel system and IC:

-to4e 57 trim
-rtek 1.7 chip
-720cc secondaries
-intake
-exhaust

other than the mods listed, everything else is s4T stock running on pisswater (only the best for us californians!) 91 octane.

 

Without the benefit of a wide band, and with 720s and NO other fuel mod, I would probably not venture much past 10..

 

i was the told the standard fuel system is good to about 290hp,but the injectors are then giong into overcycle.its not worth pushin the boost until good fuel pumps r installed.but i would think 9psi isnt too much too run. a mate of mines running 16psi with a frontmount and a bosch motor sport fuel pump. also how much boost will depend on wat fuel pressure u have

 

TII fuel pump is the FIRST thing that must be changed.

 

actually I would get that thing on a dyno pretty quickly because the rtek1.7 chip is for a stock turbo not a hybrid.

 

oh i forgot to mention a walbro 255lph fuel pump will be going in. even though the rtek chip is designed to run 720s with the stock turbo, i dont see why i shouldnt use it with my to4e. i know it will limit me to a certain degree if i try to run higher boost, but it was meant to control 720s with the stock ecu right? or am i wrong and 720cc secondaries are too small for my current turbo setup to be producing good, "safe", horsepower figures?

im a n00b to rotary tuning, but i suppose everyone starts somewhere right?

 

Your best option is to go to a dyno with a wideband O2 sensor to figure out the exact boost you should run. We can guess, but you can't beat precision measurements.

 

I have the same setup as you almost with a hybrid turbo and 720cc secondaries an upgraded bump and the rtek chip however the rtek chip has a fuel map for the 720cc secondaries and its set to the stock turbo however when you put in a hybrid turbo it throughs the a/f #'s off because of the larger turbo thus probably making it run lean.

 

A larger turbo will flow more air at the same amount of boost thus changing the volumetric efficiency of the engine. This will throw off the air/fuel raito's because an engine is tuned based on the efficiency of your whole system. The larger turbo will also most likely change where your peak V.E. occurs thus changing the whole shape of the fuel maps.

The tune will be close but not right, the best way you could bandaid this is by getting a wide band on it and uping you fuel pressure to accomidate for the lack of duty cycle. I would also recamend a piggy back fuel computer and some dyno time to fine tune the fuel mixture.