Title pretty much says it all!

The exhaust smell is awful- reminds me of the situation I had when I put in new (bigger) injectors and didn't modify the chip. Problem was solved once I chaned the constant.

The car is an'89 (mass air). The cam is basically mild but the lift is significantly higher than stock.

I don't know about drivability yet (tomorrow) so this could be the subject of another post.

Any ideas? I'm going to pop over to Third Gen and talk it up there too.

 

where are u from? what cam did u install? and who did the install? i am from barrie, just up the street.

 

Did my own install of a gm "zz4" which is the cam used in the ZZ4 crate engine.

 

i know thew camshaft....did your own install, cool! how did it go? going to cayuaga oct 23rd if you are interested. btw, i read an early post of yours.......actually headers do make a difference on our cars. Gained about 2.5 MPH with exhaust= 25 CHP.

 

The installation went well- although much slower than anticipated.

I made sure I checked everything twice. I didn't count on this rich thing, though.

Cayuga? No. I don't do the track thing. I only tinker for fun, I don't want to be (more) obsessed.

 

your no fun!! let me know how this ZZ4 works with a basically stock L-98? or is it stock? what is done to your motor to a T..........

 

Engine's stock. I'll let you know as soon as somebody ventures a couple of guesses as to a fix
We'll see. All I can say at this point is "ttt"

 

Performance cam theory 101.

I don't know the specs on the ZZ4 off hand but it is very likely that it has a lot more overlap at idle than your stock cam did. Overlap refers to the time that both the intake and exhaust valves are open. At higher RPM's this helps make more power because of the following.

As the hot exhaust gasses rush out of the cylinder they create a negative pressure inside the cylinder. This helps the fuel / air charge be drawn into the cylinder through the open intake valve. At high RPM's this allows more air and fuel to be drawn into the cylinder, where it combines for a bigger explosion which means more power.

At low RPM's everything is moving MUCH slower. There is actually time for some of the air / fuel mixture to travel in through the intake valve and straight out the exhaust without ever being burned. This is why the car smells rich, you're blowing unburned fuel straight down the pipes. You can correct for this somewhat by leaning out the idle fuel mixture in the computer chip, but it is still going to happen to an extent.

This is why as you go with a more aggressive camshaft it's harder to pass emissions. Everything that makes your engine more efficient at a higher RPM costs you efficiency at a lower RPM, and this is where you will fail emissions. If you make the cam very efficient at low RPM's it won't be able to fill the cylinders quickly enough at high RPM's and it will cost you upper end horsepower.

You can help your car in a number of ways. Lean out the idle and make it idle a little faster than stock. I also promise you that you're now running lean on the upper end. You really need to get everything you need to program a chip and then get to the dyno. Spend some time with the wide band O2 sensor and get it tuned out right. If you don't do that you're wasting a lot of time and gas trying to "guess" on the tune.

 

Nathan is right. I have the ZZ4 and you really need the chip done to go with it. Im on my 4th burn and it still idles a bit rich. Did you get your Datamaster going ? If so try and get your IAC #s down to 30 or less. This will help.

 

Let us know how it turns out. I'm interested in this cam.

 

I will let you know.
I may have a lead on a bin...