will_p

I have a lsj manifold going on a 2.2 ecotec that I am smothing out the inside and measured the collector. It is about 1.8" where the sensor goes and then opens up to 2.25".

Now I have read the post that has the different cfm ratings and it states a stock lsj manifold flows 425 cfm. Is this really possible when the collector is not 2.25" the whole way through? plus once you have the sensor in there it will be in the way of flow even more.

My thought is that maybe it is able to flow this much because the cylinders fire at a different time therefore only the air from one passes through the collector at a time?

My 2 biggest questions is how can this small of an area flow close to a 2.5" downpipe? and should I remove as much of this area without making the walls to thin or is there a reason for this design?

Has anyone ever seen actual flow charts on the manifold and not calculations?

thanks

will_p

Any ideas? what I do know from the guy who posted the cfm #'s is that some places claim a 7% increase in flow and some claim a 30 cfm increase. 30 cfm is 7% of abour 428 cfm, so I guess this is probably accurate? any ideas from anyone feel free to chime in.

YSUsteven

Can't tell you why, but it was made for a motor with 25%+ more horsepower, so should be fine the way thats its made.

Air is compressable, and what will happen when the air goes from the 1.8" to the 2.25" section is it will slow down and lose pressure.