18rg mikuni solex carbs?????? HELP!!

[luke ae86]

hey guys, a friend just converted HIS 18RG TO EFI and he sold me his mikuni solex carbs.. they are 2x twin 38mm barrel and was just wondering if they would suit my 4a-c if i got them re jetted to suit if thats possible?? anybody done this before?? would it require a custom manifold? im out of my depth here

[2004lowlux]

first youd want to see if the manifold fits on

[luke ae86]

if worse comes to worse i will fab up a manifold, i am handy around shop tools but im unsure as i was told a webber 38/38 dgv would be the limit of carb upgrades for this engine and it seems to me that a twin barrel mikuni solex 38mm carb is equivelant to the webber38/38 dgv and i have two of these mikuni solex carbs??? but then another guy told they would be fine?? both guys are qualified mechanics so i neeed a third opinion

[2004lowlux]

i always thought the best upgrade for a 4a-c is a 4age lol! i cant see it being an issue they might need rejetting down to suit the 1.6 they should cope as long as they're set up correctly

[luke ae86]

yeah i know im taking my sweet ass time in building my off tap 16v small port but i want more power in the mean time

[o_man_ra23]

I would look at fabbing a manifold to use a single mikuni. The lower revs and smaller capacity of the 4A-C should utilise a single carby reasonably well. If you can get the barrels to feed 1 and 4 through one barrel, and 2 and 3 out of the other barrel, that would work the best as far as flow through the carb is concerned.

These would actually be 40mm carbs, choked to 38mm (standard fare for 18R-G units), hence the 38mm butterfly.

Of course jetting the carbs right down would allow you to use them as a pair of twins.

[Rhyno]

Hey Mate,

Keeping them as twins would make it easier to cut and shut a 4AC manifold to suit and give more potential for power.

To really get the most out of them you would want to upgrade your ignition system as well to get the most of the extra fuel; A heavy duty coil and leads, some Iridiuim Plugs at a minimum, and new dizzy cap and rotor, should make for an interesting package.

[Rhyno]

Double Post...

[o_man_ra23]

A lumpy cam would also help to make the carbs work a bit. With a single cam 4A-C that shouldn't be too hard to swap out too.

[Celica RA45]

the venturis are std 34mm in the 18rg solexes and mains are 145 and airs are 170 pumps and the butter flys are 40mm

[Rodger]

Go with using the pair.

If they are indeed Type Ts, for your 4A-C i suggest a change of Main Fuel Jet from the normally #140 to a #125 and the Pilot Jet from the normally #63.8 to a #57.5. The Outer Venturi (large or choke) change from the normally sized #32 to a #30 if you can get them.
Remove as much of the polution reduction stuff off them and block the rear carb/rear barrel vacuum port, down near the throttle shaft.
While you build up a manifold consider how you are going to make the throttle mechanism. If you can space the carbs correctly you can make use of the existing throttle levers and balance mech, perhaps shortening the rear carb lever tab to bring the two carbs closer together. You will need to make up a cable assembly.

Do you plan to run the carbs on the 4A-G?

Regards
Rodger

[luke ae86]

thanks for the info guys, i spoke to a few people in the know at the local carby shop and he told me it would be way too much trouble than what its worth as these particular carbs are very hard to source parts for, and as im not intending on keeping the 4a-c for any longer than a year im just going to get the biggest downdraft webber i can find and whak that sucker on there, it was a nice idea but i have been talked out of it, and nah rodger im building it up to be a standard small port 100kw engine, with all modern internals and alot of head work i have an addiction worse than heroin..... the sound of a toyota 1600 revving at 10,000rpm gotta love it