70's emission controls

Post your E12 technical questions and comments here. Please, no off-topic posts.

Moderators: Mike W., Pierre

Post Reply
T.Hanson
Posts: 1696
Joined: Wed Jul 26, 2006 7:39 am

70's emission controls

Post by T.Hanson »

The charcoal canister, throttle switches, catalytic converter, oxygen sensor. Mandatory smog testing, or no longer for state reasons. $100 to replace the charcoal filter, $$$ for cats...

Question for the real tuners, sans the political band aids : Is a 528i engine maintained in excellent condition still in need of the (old) fiddle fuddle air attachments ? The age of the cars alone allows legal cat free exhaust systems. The number of survivors on the road, polluting ? IF in excellent mechanical condition.

What happens if I take all the old smog things off ?
User avatar
Mike W.
Posts: 2889
Joined: Wed Aug 30, 2006 12:12 am
Location: Sonoma County

Post by Mike W. »

About the only smog components on a 528i are the evap system, the cat, O2 sensor and the little green vacuum valve on the t stat housing. None of the air related parts are emissions related, just part of the FI.

None of them hurt performance or mileage any, but if you disconnected the O2 sensor you would probably lose about 2MPG. It was really an exceptional system for its day, especially compared to the madness of it's predecessor, the E12 530i.
Mike W.



02 525ita. Wife's, aka grocery getter
02 530i. New to the fleet, 3 pedals.
03 QX4, AKA the Datsun. Finally got the 4WD vacationmoble to stop smoking.
07 Xterra. Still on the DL, a purchase from hell.
canada karl
Posts: 1065
Joined: Tue Jan 06, 2009 3:50 pm

Thermal reactors?

Post by canada karl »

I took them off my 76 530i years ago. Was 76 the only year that had them?When did BMW stop using those cylinder head crackers?
1976 530i. BMW 59 Triumph TR3A(rolling resto). 67 Triumph TR4A(salvageable). 86 900S Winter car
User avatar
Mike W.
Posts: 2889
Joined: Wed Aug 30, 2006 12:12 am
Location: Sonoma County

Post by Mike W. »

All 530s used the full thermo reactors, EGR valve, smog pump and retard only distributor. All 528s used the much more modern O2 sensor and three way cat. 78/79 was the change. 528i heads still crack, but nothing like the 530 ones. Castings changed over the years with an improved one I think in '80 and a still better one around 82. I believe metallurgy changed also to a more crack resistant alloy.
Mike W.



02 525ita. Wife's, aka grocery getter
02 530i. New to the fleet, 3 pedals.
03 QX4, AKA the Datsun. Finally got the 4WD vacationmoble to stop smoking.
07 Xterra. Still on the DL, a purchase from hell.
T.Hanson
Posts: 1696
Joined: Wed Jul 26, 2006 7:39 am

Post by T.Hanson »

Hey, maybe there's hope. There I was, noticing the technical FAQ list (after how many years ? ) and there was / is a pdf, printable file by Mr. Peter Florance, for me to read.

All about how the 528i injection system works. Every sensor, part and piece. There's a chance I might learn things, and try things, instead of just posting questions about junking charcoal pots.
Post Reply