flat spot and misfire

[Stockevo51998]

Hi all, I have an E5 which I have just fitted an E9 80 series, new o2 housing and 3 inch downpipe system, since fitting I have a flat spot and misfire around 4000 rpm, Im not running the car at high boosts still at 0.8 bar on boost controller as I haven't had the map tweaked yet. Im running bpr8es plugs with a gap of 0.55 the car was running fine until I fitted these parts.

 

[B6lee]

I'd say your fueling is miles out. Also your plug gaps are too small

 

[Stockevo51998]

Thanks for the reply if I get a log from the car for the fuelling using a tactrix and post it up would you be able to give me a few pointers on how to sort it out so it runs better before I have the map tweaked as I don't want to blow the engine before I forge it in next few months also what plug gap should I run

 

[B6lee]

Get it to a reputable mapper now.
Getting it right means looking at more than just what you read off a laptop.
Also it could be a different problem that's causing the issues you mentioned. Difficult to tell without seeing the car.

Plug gaps I'd say 0.65

 

[Simon@NTS]

I run BPR8ES at .55 no problem, a datalog would be a good idea, or get it over to FCM