Performance camshaft and emissions.

[MagicRat]

How would installing a mild performance camshaft in an otherwise stock EFI engine (not OBD II) affect drivability and emissions.

My wife's car is an '87 Mustang with a 2.3 4cyl, auto trans, and 213,000 km. I am rebuilding the cylinder head to correct an oil AND coolant burning problem, but otherwise the car is like new.

Since I cannot ever leave things alone, I would like to install a Crane mild performance camshaft, (intake 272 deg advertised duration, exhaust 280 deg.) So, how would this affect the stock EFI system, especially in terms of emissions?
Two problems come it mind......the longer duration intake lift may reduce manifold vacuum, causing the MAP sensor to send a misleading signal to the ECM.
Also, perhaps the extra flow at wide open throttle would go beyond the fuel deliviery capabilities of the EFI system, causing a lean condition

Finally, yes I know this is a poor platform for a project car, but I hate the idea of installing a new stock camshaft when a bit of power can be gained for no extra effort by installing a performance cam.

Thank you any input you might have,

[curtis73]

You are so much like me its scary.

The big thing that affects vacuum, emissions, and drivability is valve overlap. You can go up one step in duration and widen your LSA. Actually, you can probably get away with just more duration and still not notice much drivability difference, but widening the LSA will theoretically keep the same overlap and therefore same vacuum and idle. The increased duration will shift your cylinder pressures up in the RPM range which might increase NOx. The other downside to longer duration is HC emissions, but for the most part you have some play room. Check out this thread. It has nothing to do with Mustangs, but there is some good cam and smog theory there.

http://impalassforum.com/noncgi/ulti...c;f=1;t=000062

[MagicRat]

Originally Posted by curtis73

You are so much like me its scary.

I will take this as a compliment
My thoughts too, after reading about your twin turbo 500 cid Caddy.
At some point I'll tell you about my Fleetwood with a .60 bored Olds 455 with just about everything.

Thank you for the input on the cam specs. There is some room to tune a bit without the car going too dirty. Emissions tests for older cars do tend to loosen up a bit around here.
The worst that will happen is that I'll have to put the old cam in, just for the test, then swap it out afterwards, which is very easy in this car.