okay the professionals and the b series gurus thats been doing this for a long time really need ur help..

i'm building a b series motor.. my main question is based on ALL motor.

1. say i wanted to slap on a 73mm throttle body to a stock manifold say 63mm would it even line up... because the diameter of the Tb would be bigger than the IM and it wouldn't line up.. the tb would overlap..

2. okay is it possible to have a port and polish head and not port the manifold. how would the gasket work.... baisically ur putting a gasket on the head where its been ported so the holes lines up.. but lets say the manifold isn't how does that work.


3. if u port just the head and not the manifold is that restricting air flow?

4. what about if u port just the manifold and not the head.. i think this is restricting airflow because all that extra air can't go in.. into a smaller hole so backpressure is created... i guess...


i would appreciate if u help. i search but notihng..wanna build me a nasty b series motor thanks..-

 

theres not going to be anything nasty about a polish or an oversized TB.... lol, try going a high revving and compression route.

 

bump soneone that can answer these questions

 

a larger TB will reduce the air velocity. you want velocity. (the 30mm or so TB on the cx is meant to be restrictive. all the others do just fine untill you are pretty far into building a motor)

if you do go with a bigger TB or port the head or open up the manifold you would just match the mating inlets. some call this port matching.

invest a few bucks in a book or two on power tunning and porting. i can't explain things as well as those guys but i can tell you that your ideas on how air flows into an engine will get you in trouble and hurt your engines potential.

i'll give you one tip i think i am beginning to understand myself: consider that the valves are opening and closeing pretty fast creating waves of high and low pressure air as well as pulses that move up and down the runners. timing the pulses and the high pressure waves to be at the back of the valve when it opens is more important that hogging out the ports or the TB.

Honda has already put half a century or racing experience into these motors. it's gonna take some considerable research to build on top of that.

 

say u enlarged the manifold ports but not the head.. how would a gasket work for that... i don't get how that would work a larger hole with air going into a smaller hole isn;t that restrictive.. and do they even have a manifold gasket like that..

 

you would just trim the gasket to fit... it's not hard. also the gaskets are often bigger than the ports and runners

 

you sound like you got pretty good plans, except in the All Motor section, more people might respond.