BALC: Sizing throttle bodies

Rich H · Post by **Rich H** » Thu Aug 09, 2007 9:28 am

Hey all,

When choosing pikey bike throttle bodies how do you get the size right or is it just suck-it-and-see? Say for example if I wanted to fit ITBs to a 2L van engine?

The Audi 20V 5pot is too much of an unknown at the moment so its bike throttles and EFI for the porker (Eventually

)

CHeers
rich

mac · Post by **mac** » Thu Aug 09, 2007 8:56 pm

You need Robin for this one I think......but I'll have a go.

I'd assume that you need to do some calculations for flow rates and cubic capacity.

I suppose if you can work out how long the valves are actually open for then you can work out how much air it can suck in on any give stroke (easy shug)

Alternatively (and this is a total guess) if you have a single TB & Plenium you could work out how much air flowed through the TB into the Plenium on a single stroke and then 1/4 it.

Mac

Rich H · Post by **Rich H** » Thu Aug 09, 2007 10:31 pm

Cheers gents!

I'm looking at GSXR 1000 TBs as they are plentiful and cheap, I reckon a 1000cc at 14000 rpm needs more air than a wheezy 2000cc at 6000 rpm.

The calcualtion works as follows:

Available cash - living expenses - SWMBO tax - broken / worn out bits + crap flogged on ebay = amount left

Amount left + Ebay = size of throttle bodies

hiscot · Post by **hiscot** » Fri Aug 10, 2007 6:36 pm

some bike t bods are not suited to cars and can even be to big
check out

http://www.locostbuilders.co.uk/

realy intresting site with all the info you need