I have a street ported motor, an intake, catback and high-flow cat. Is it safe to run a downpipe with this on a stock ECU?

 

no. get a stand alone and a good tune. before you go full exhaust.

 

Yes.. with the highflow cat at 10 PSI you should be ok on the stock ECU. but you must keep the boost at "10 psi max" its been tested and proven. anything over 11 psi will pop the motor. if you are going to boost above this you will need a pfc or pettit chip. read and search under stock ecu and 10 psi rule. there is a lot of info on this.
Jeff

 

I would be carefull. Just because boost pressure is consistant doesn't mean that air volume is. High flow cats add minimal restriction to the exhaust. I would definately add an ecu asap. Not worth blowing a motor.

 

I've been running a downpipe, high flow cat, and catback with intake for a long time on the stock ECU and have put the car in the position to nade many many times and still runs strong. Even in 30 degree weather at 8k RPM the car still wont give. That's just my experience though.

 

You are living on the edge of expensive adventures...

 

To be safe go rent a wideband and test when the weather is cold..

 

I wouldn't risk a motor for it.

 

You'll be at the limits of the ECU's ability i.e close to running lean/detonation. As stated above hook up a wide band to see what your situation is exactly

 

if u can limit your boost to 10 psi u should be fine. but why not get a power fc and crank that puppy up alittle.

 

im running intake,dp,high flow,cb,ic and streetport. IM on stock ecu and have boost controller set to 9psi. Thats so if i have a small spike it wont be that bad, i have yet to spike with my current boost controller setup. I have had no problems but am saving up to get the Power FC. DEFINATELY the next thing on the mod list.

but its possible