Did i just get richer or am i running leaner after my 1.6 roller tip rocker swap? Car is a 91 350 tpi. The exhaust note is noticable throatier and sounds good. Feels like I picked up about 10-12 hp or so. However, i have noticed than when i used to turn the fuel pressure up on my car that the car's exhaust would sound deeper. I assume this would be a rich condition. So, with this rocker swap, then am i running richer or leaner? I guess i could connect my laptop and have a look in Datamaster at the BLM's,. but i havent had the time lately.

 

Since you're TPI the ECM should be using the o2 sensor to adjust the injectors.

Rockers are just a multiplier. You're just pushing the intake and exhaust valves a little further allowing for extra flow. Fuel is injected in the lower manifold so it should be mixed with air before it reaches the valves.

 

if anything leaner

 

Buddy did this swap and got a lean code. he then put AFPR on and made code go away for awhile anyway.

 

I guess you can think about it like this:

Why did you install the higher ratio rockers? Well you probably wanted more power.

Therefore, how would the rockers give you more power? Whenever I explain what rockers do, I say that a rocker is simply a see-saw as you can observe that when one side goes up, the other goes down.

Now the higher ratio (1.6.1, 1.7.1, ect.) only means that the position of the pivot point is now higher which means that the ends of the rockers (see-saw)are going to be going down and up farther than normal, hence you are opening your valves wider and allowing for more air/gas to go into the combustion chamber.

Now what does this all mean? Well if you are allowing more Air/Gas and not changing the rest of your setup to compensate for it, if anything you will be running out of gas/air (lean) but dont worry, rockers wont do something that drastic, thats what your O2 sensor is for. It will sense that you need more gas/air now and will compensate for it.

Your ECM will allow your injectors to spray more fuel to reach the perfect 14.7 Air fuel mixture that your ECM tries to keep your engine at.