Author Topic: individual throttle body design input needed. (Read 4934 times)

kowalski · « **on:** May 26, 2007, 10:53:55 AM »

Ok, so i visited this site
http://www.jenvey.co.uk/~TBins.htm
and going by their charts i need at the maximum a 45mm throttle body for a naturally aspirated engine. going by the planned modifications of a 2.1L with custom JE pistons, rods, an m47 crank lightened and knife edged. All of this balanced and blue printed. Top end will be a head with lots of port and polishing work, light weigh vw lifters titanium retainers with new stiffer valve spring and oversized valves. Cams i currently have are 264 degrees rotation and .388 lift, I will probably leave them at this spec until a later date depending on funds and dyno results.

So, i figure i should at least hit the Metric mechanic number of 205hp with this settup giving me at least 51.25 hp per cylinder. I don't want to end up with throttle bodies being the limiting factor so i will allow for 60-65 hp per cylinder and get myself a throttle bodies between 42 and 45mm. This chart is assuming 150mm intake runners after the butterfly, so i will of course built to this spec, and 50 mm trumpets to give the system an over all length of 200mm which, again according to their charts is optimum for an engine reving between 7 and 9,000 rpm. Of course i should be on the lower range of that, so perhaps i should move to a 25mm trumpet? This is going to be my first set of ITB's that i build and i would very much enjoy doing it right the first time...

zav3n · « **Reply #1 on:** May 27, 2007, 09:20:27 PM »

im currently working on a itb setup with 42mm gsxr itbs off my cousins totaled 05 bike. ive striped it down of all the crap on it. ive jb welded the stock Fuel injecter inlets. the fuel rail is gunna be stock... for now. im planing to get this set-up up and running and then rebuild my enigne and throw bigger injectors on. im going to cut the stock intake manifold and weld it to the itbs.. ill post pics soon..

kowalski · « **Reply #2 on:** May 28, 2007, 01:33:14 AM »

Quote from: zav3n;26670

im currently working on a itb setup with 42mm gsxr itbs off my cousins totaled 05 bike. ive striped it down of all the crap on it. ive jb welded the stock Fuel injecter inlets. the fuel rail is gunna be stock... for now. im planing to get this set-up up and running and then rebuild my enigne and throw bigger injectors on. im going to cut the stock intake manifold and weld it to the itbs.. ill post pics soon..

nice. When do you think this is going to be done?

dino245 · « **Reply #3 on:** May 28, 2007, 12:19:40 PM »

I am using a set of Hayabusa Throttle bodies which are 46mm and are designed as 4 individual components and can be seperated and spacers installed to acheive the 91mm bore spacing. I had an aluminum adapter made that incorperates the port shape change and the mounting to the head. I will get some pictures.

zav3n · « **Reply #4 on:** May 28, 2007, 02:44:17 PM »

i think ill be done early next month but if i go the route that dino245 went it will be done probably sooner.. please post some pics!!! especially of the way you spaced the itbs to 91mm
thanks
-zav

nickmpower · « **Reply #5 on:** June 01, 2007, 02:45:01 PM »

Quote from: dino245;26706

I am using a set of Hayabusa Throttle bodies which are 46mm and are designed as 4 individual components and can be seperated and spacers installed to acheive the 91mm bore spacing. I had an aluminum adapter made that incorperates the port shape change and the mounting to the head. I will get some pictures.

any pics/ more details on your motor?