pros and cons on dual webber 45 side drafts

[sam]

i wanted to know whats the cons and pros on doing dual webber side drafts 45 mm for autocross . experience please

[datzenmike]

On a stock motor they're too big. You want the intake velocity to remain high. Perhaps on a purpose built motor with modified head and cam with big rear gears to keep it revved up.

[sam]

well my motor is semi built , it has a mild cam with zx valves port and polished and head shaved alot ! peanut head and l20b block with racing oil pump and electronic dizzy , 6a msd

[sam]

its for my scca car , and weekend car , im wondering how bad is my mpg

[sam]

So I'm guessing its not worth it ?

[hobbes_the_cat]

If you're worried about mpg it's probably not for you. It sounds like your motor is fairly built tho, so some big sidedrafts should really make it sing compared to a 32/36 downdraft. Twin 40s might be a better choice if you want to drive much on the street and not run at WOT all the time.

[banzai510(hainz)]

wHAT hOBBES THE cAT SAID!

I run 40mm Mikunis and have a 3.7 GR in my 510 and get about 20-22 in my 510 with regular driving.

 

If racing ? Who cares your there to win.

Im thinking nothing wrong with Webbers but its harder to understand the jetting numbering system webbers got. Its not incremental the numbering system.

 

40s might be better and a low gear ratio also.

 

You could try a 38/38 weber DGES if one is avail and use the stock type manifold. But I like sidedrafts myself.

downdrafts are good daily driver simple carbs.

[sam]

currently i have dual su , for some reason when im in hard turns the car wants to stall when i get off the turn like if inran out of gas because my wide band shows no fual and then it jumps back to normal , idk if i should stay with my SUs or got side draft webers , i would love some mikunis tho ! wish some one sold me some