Running a 10% bigger injector for #3

The temps I saw, front stayed at the same temp, rear dropped quite a bit. Changing the port size can lead to other issues, definitely worth some research on that aspect though, just a little outside my realm of knowledge.

I do recall seeing internet lore that #3 runs leaner due to intake design and such, but that's been a lot of years ago that I read it, don't remember the source.

I believe Anthony Hyde says the factory race cars did on his site. I'd want a lot of proof this was happening in my specific engine before trying something like this.

And don't think it's a good choice for a street car at all.

https://people.physics.anu.edu.au/~amh110/group_a_volvo_specs.htm under "fuel injection"

will740turbo said:

I am wondering if +10% on one cylinder will really richen the exhaust enough to lean out the other 3. I don't know what engine the volvo race team did this with - for all I know, it could have been CIS with no O2 sensors.

I don't want to put in the effort to change to a custom ECU. I would never stop fiddling with it.

Click to expand...

Yes it will. However the volvo racing team was not trying to meet emissions or fuel mileage standards. They were not running the car in closed loop, your car should be in closed loop. In open loop what was asked will work, open loop doesn't care what comes out the tail pipe. Open loop fuels off of fixed tables, closed loop looks at the O2 content of the exhaust to determine fueling trim.

Sounds like why I don't like graphic EQ's, they have to be adjusted for every song. But I love my custom ECU.

This is mentioned on 240grupp-a.se as well so I am inclined to believe it. I still wouldn't do it on an engine that isn't almost always running at full throttle.