BHAF - HP vs. Efficiency once and for all

[JWareing]

Hey all - thought i would post this here because im not sure it fits neatly into a "generation" discussion, maybe it does - but i was thinking of it as a more general question:



I have done a lot of searching and reading threads here on the merits of adding a BHAF in to the system on CTD engines... but most of these discussions seems focused on "upping horsepower" or "getting that great turbo noise louder" neither of these am i against on principle.



But i am having a hard time findind a real answer to the question: all other things aside, does putting in a BHAF increase the efficiency/fuel economy of running my truck? and in what other ways does it affect it - both good and bad?



My 1996 2500 4x4 bought used this summer came to me with a home made "medium honkin air filter" basically a medium K&N cone clamped to a homemade PVC elbow routed into the turbo intake..... propped up where the stock filter box used to be with some home-made hardware... .



After I did my first oil change - ( i dropped the filter to turbo elbow to get at the oil filter) I noted dust on the collar of the turbo - and said "Uhoh!"



worried about doing further damage before resolving my questions- i put the stock filter box back in and put a stock flat air filter back in. I cant say that i have noticed a big change in fuel economy, but i havent been driving the truck alot lately for a fair comparison... .



but i do notice i dont hear the turbo spool up anymore, and it does seem to "hesitate" on acceleration, and that if im on the pedal, then let off- there is kind of a "cough" from under the hood that i didnt notice prior to making the change... ... . any connection? and - does more air flow only contribute to noise/acceleration- or does it make me more fuel effecient also- or none of the above?! lol im confused!



PS- the only other thing I wanted to note for you sharpies is that the guy i bought the truck from had removed the "resonator" from the exhaust... . what effect if any does this have on things?



Thanks again for entertaining my long post and questions, and I look forward to any insight you guys can offer -



Sincerely- an enthusiastic but still green CTD newbie-



Jim

 

[Joe G.]

There is some efficiency to be gained by a better flowing air filter, but for a stock engine the gain is not that effective.



There is no resonator on a '96. There is a cat convertor in front of the muffler. It's illegal to remove it, but if you are not somewhere that inspects for it being there then it's not a big concern.



The cough is turbo bark. Not a problem unless it's excessive. A stock '96 does have some turbo lag. Not really a problem, but it can be reduced by doing some adjusting on the AFC.



You should fill in your signature with at least the year and transmission type. Location would also be helpful for local members to give you a hand if you need it.



Email me at -- email address removed -- for instructions on blocking the KDP and my write up on the 12 valve fuel system, how it works and how to fix it.