280 cam, what AFR?

[Elliot]

I just installed a 280 cam in to my m20. The motor was rebuilt at the same time. I will be installing exhaust and intake. Do I need to tune the AFM to change the AFR or will the motronic be capable of correcting the AFR?

Elliot

[digger]

I just installed a 280 cam in to my m20. The motor was rebuilt at the same time. I will be installing exhaust and intake. Do I need to tune the AFM to change the AFR or will the motronic be capable of correcting the AFR?

Elliot

neither

[NC325iC]

that wasnt much help was it

[Elliot]

nope not much help!!
This is my first E30 and I am not familiar with capabilites of the motronic unit. I used to drive subaru wrx. The subaru ecu is very adaptable and minor mods wont hurt the car. I just want to know if anybody had use a WO2 to check their AFR after the cam install.

[92 mtechnic cabrio]

I have a feeling the motronic will be able to cope with it fine.

I say this because I don't recall any threads about people switching their cams and then suddenly having drivability problems (besides the rougher idle). I'm also keeping in mind that I read in a thread that the AFM was laser-precision calibrated, and you shouldn't touch the AFM. (I say this even though I have a tweaked M30 AFM)

[Elliot]

anybody else want to throw in some of their thoughts?

thanks 92 mtechnic

[MrK]

Before I stroked my engine, I put my 304 cam in there, and as far as I know the AFR was just fine. So I wouldn't worry if I were you.

[Elliot]

at what rpm are iddling, my car is very rough
i need to check the plugs and the coolant temp sensor!!

[digger]

Elliot, do you realise that the E30 community is so cheap that it doesn't bother with tuning. We rely on theories based on nothing so you won't get anyone who has checked the AFR after only a cam swap.....lol.

Don't touch the AFM unless it has been touched before the spring should be a few clicks from the fully closed stop, and Motronic won't adjust the AFR for the cam becasue at WOT the AFM flap is against the fully open stop from around 4000rpm onwards so the fuelling will be preset from the chip regardless of the airflow. i wouldn't think it would make it run too lean to cause problems but you can always get a WBO2 and see for yourself and get a remap if its way off.

[92 mtechnic cabrio]

don't forget that aftermarket cams do make for a rougher idle. I'd talk to somebody in person with experience and find out if that rough idle is indeed exclusively caused by the cam

[Elliot]

but I mean really rough almost stalling!!

[Elliot]

I have a WB02 so i'll check the air fuel ratio I was just being lazy!!

[nando]

be sure to check for vacuum leaks.. my idle is pretty smooth with a 284 @ ~600rpm.