if i got an apexi gt spec exhaust, a down pipe, a blitz sus intake and a hks ss bov would i need to change my ecu or would the stock ecu be okay. also is the blitz sus intake for off road use only cuz i thought it was 50 state legal

 

Is that a general rule? 5+ engine mods = ECU?

Just curious...

 

Damn, is anyone reading the common sense thread?

This has been discussed 500 times. Recently.

It has been proven by dyno testing with a wideband that the stock ecu can handle pretty much all of the bolt-ons IF YOU KEEP THE BOOST AT 10 PSI.

Series7, he would NEED a boost controller to keep boost at 10 psi with those mods. You cannot run over 10 psi with the stock ecu (above 4500 rpm, the stock ecu will let you hit 11-12 on the primary) or you will hit fuel-cut.

EDIT: Series7, the 3-mod rule is bullshit. Wade Lanham proved it false, see his website for the proof. Several of us have also proved it with dyno testing.

 

The general rule is that you need an upgraded ECU when you either:

a) switch out the stock twin turbos for something larger
b) begin boosting over stock boost levels
c) using larger/more injectors

Using the stock ECU and any of those are not a good idea. You can put every bolt on mod you want, if you stay at stock boost levels you are fine.

Keeping it at stock boost levels can be the problem though...

 

http://www.newwave.net/~flanham/wlan.../3modrule.html

 

This assumes healthy injector flow & a clean fuel filter...

If you have close to 80K miles on your car then you should have the injectors cleaned & flow tested. Replace the fuel filter every 25K miles.