Been putting some thought into the ideas of IMRC deleting and the benifits associated with a street driven B head 4v or the ideas per say of how the IMRC plates could make a centrifugal setup car more fun.
All Gunking Aside
A concern with most is the upkeep of the IMRC plates. The secondary runner is dry. There is no fuel and thus seems to lead to a froth buildup on the plates. Deleting prevents cleaning and failure. My posing question is would increasing port velocity deter this?
The IMRCs are in place to keep runner velocity maximized. The B head has a combined runner volume of something near or over 230cc. That's insane for a 281 ci engine. People lose the IMRCs for a loss of restriction and simply gear the balls off the car to keep engine speed and runner velocity higher. Almost like a bandaid fix.
Now with a centrifugal setup you now are starting to fill those single set of runners. At lower rpm points. Increasing the velocity until transition. I would feel a car moving a displaced volume of @ 315 ci or so at lower rpm levels would really make for snappy lower end with the primary runner of around 120cc. Despite having a numerically lower gear in the rear; say 3:73s for my instance. Obviously there would be more air during IMRC transition that could be harder to tune around like a part throttle lean. Has this beeen documented? Also this greater volume and velocity of air could keepthe plates cleaner. Documented?
Does anyone have a dyno of a centri car with a back to back IMRC and delete test? Id be very interested in seeing the results.
Thoughts? Opinions?
$.02
All Gunking Aside
A concern with most is the upkeep of the IMRC plates. The secondary runner is dry. There is no fuel and thus seems to lead to a froth buildup on the plates. Deleting prevents cleaning and failure. My posing question is would increasing port velocity deter this?
The IMRCs are in place to keep runner velocity maximized. The B head has a combined runner volume of something near or over 230cc. That's insane for a 281 ci engine. People lose the IMRCs for a loss of restriction and simply gear the balls off the car to keep engine speed and runner velocity higher. Almost like a bandaid fix.
Now with a centrifugal setup you now are starting to fill those single set of runners. At lower rpm points. Increasing the velocity until transition. I would feel a car moving a displaced volume of @ 315 ci or so at lower rpm levels would really make for snappy lower end with the primary runner of around 120cc. Despite having a numerically lower gear in the rear; say 3:73s for my instance. Obviously there would be more air during IMRC transition that could be harder to tune around like a part throttle lean. Has this beeen documented? Also this greater volume and velocity of air could keepthe plates cleaner. Documented?
Does anyone have a dyno of a centri car with a back to back IMRC and delete test? Id be very interested in seeing the results.
Thoughts? Opinions?
$.02
