Stock Cpu help
 

Hi guys, i own a 99' series 8 and im currently going through the reliability mods. Im about to install down/mid pipe + exhaust system but i have heard rumors that the standard cpu is so sensative that once i change the exhaust system it will automatically start running too rich and back fire alot , anyone confirm this?
thanks.

you will go to rich. its all in the FAQ at the top of our section.

i dont really know if the series 8 have that problem though. you should reallyl try posting in your regional forum

It will not get too rich. It will get a little leaner due to increased flow.

What can happen with exhaust mods is that your boost levels will rise. The FD fuel system doesn't have a lot of extra fuel capacity, so if your boost goes up and you don't mod the fuel system and boost controller, you can end up with fuel cut, or worse, a blown engine and turbos. If you install a full exhaust (no cats) this will happen right away.

You need to install a boost gauge first, and know what your boost pattern looks like. If you want to stay on the stock ECU, you must keep your boost within 1psi of stock levels. If you want to go higher boost, you need to upgrade your fuel system and ECU.

Dave

Installing a mid pipe is one of the first mistakes that many new owners make. Don't do it until you have really done some research. Installing a midpipe can destroy your engine.

Just because the car backfires does not mean it is too rich. There are alot of misconceptions on here. The stock ecu cannot handle more boost as degeesaman said. I personally just tore down a motor that had detonation damage. Only mods were blitz intake, downpipe, and apexi catback. The car was driven hard in cold weather and overboosted/leaned out because of too many mods for the stock computer to handle. I put it together and made my customer install a stock intake for the time being. A full exhaust would be even worse.