Got an E-mail from ARD to bore T.B. to 55mm $100. To bore T.B. to 56mm $140.
How much gain if any will boring a T.B. to 56mm instead of 55mm give?
I think not much but I don't know, so what do you guy's/gal's think?

prolly not too noticeable, imo..

this is what afxmanufacturing (board name) had to say in a diff post..

<<< 49mm TB flows 252 cfm
52mm TB flows 283 cfm
55mm TB flows 317 cfm
60mm TB flows 377 cfm
At 8200 RPM a 122 cubic inch engine will need 290 cfm at 100% volumetric effiency, using the formula ((Max RPM/2)*Displacement)/1728. Rule of thumb is to go 10% over because a naturally aspirated engine can go above 100% volumetric efficiency because of cam overlap, header design, etc. Go above that and you kill low end because of reduced velocity, go below that you starve the engine for air at top end. 110% is volumetric efficiency is 319 cfm.">>>>

made me feel good about my 55mm purchase from them.... for forced induction, bigger=better... but for n/a applications, u may go "too big"

there are other interesting posts on that thread, its talon95stangs thread about the jeepTB order..
http://www.2gnt.com/dcforum/DCForumID13/5084.html

good luck

oh ya, i doubt u would feel the gain of 1mm bigger t/b, and the 40$ markup isnt sumthin i would invest in....

><<< 49mm TB flows 252 cfm
>52mm TB flows 283 cfm
>55mm TB flows 317 cfm
>60mm TB flows 377 cfm.....

good info!! :thumbsup

Thanks vegasdsmr that is good information.