Carb upgrade options

[manoa matt]

1978 1800 stock engine, stock cams, stock pistons, recently rebuilt cylinder head, 4-2-1 headers with free flow exhaust.

Currently considering the following options:

1) Dual 40 Solex downdraft carbs
2) Dual 40 Solex sidedraft carbs
3) Double barrel Weber 38 ADL

I know the 38 will be the least maintenance and easiest to tune, but I've heard that I need to increase compression and/or get performance cams to take full advantage of the carb.

The only reason I'm considering the dual 40's is I can get them at half of the price as the 38adl, plus they just look awesome.

Matt

[mdrburchette]

Will the sidedrafts even fit with the booster in the way? Would you have to source an intake manifold or do the downdrafts or sidedrafts come with one? You've already got the open intake on your car. I think I'd go with the 38. The 4-2-1 exhaust and free flow muffler should help performance and you can rejet the 38 for optimal performance. This is from a girl with dual 40's on both 1608 cars.

[mbouse]

gold plated dual 40's !!

[manoa matt]

Yes, the 40 downdraft comes with a manifold, and the 40 sidedraft comes with a manifold. The sidedraft setup has been recently removed off a fiat. I am running a 79 ignition with vac advance. I know the 38 has ported vacuum but I don't know about the 40's

[racydave]

All I can say is Im very happy with my 36 ADL. And it seems to want more mods...

[stefhahn]

Hi -

my experience: don't go for the Solex twins. They may look very similar to the Webers and - if in tune - will get you similar performance, but: you won't be able to find gaskets for them. And if you're going to cut them - fine - then still you will never ever be able to locate a accel. pump diaphragm - and if you will (after some years) be able to locate one, it will be the "old style" red one - which will rot away in some months as todays fuel is a lot more agressive than it was back in the 70s.
Go for whatever Weber.

ciao,
Stefan

[spiderrey]

36 ADL?

[stefhahn]

Starting with a 34 ADF or 34 DMS would be a good idea. The increase in HP is dramatic - if you have a 4-2-1 header w/ out the emission cr*p. The 36/38s are not a lot more than this breathtaking first step.
ciao,
Stefan

[racydave]

36 and 38 ADL http://www.mirafiori.com/faq/content/we ... 38_adl.htm

[manoa matt]

The problem I'm having is that I can get a 34 ADF, a 36adl , and a 38 ADL all for about the same price.

I'm thinking with my setup a 38 ADL would be to big unless I made some other mods, also my car is a daily driver so MPG is a consideration, the 38 would burn a hole in my wallet.

So if you could get a 36 ADL for the same price as a 34 ADF, why go smaller? If I go with a 36 ADL would I need to re-jet?

[racydave]

Matt, I recieved mine used, but it was a bolt on and run thing. It was dialed in well, a little fat for straight stock, but it should handle your needs. I got mine from Ralph ( the one in the pics ) and he has been very helpfull.

[racydave]

Matt, id also suggest sending out your spare dizzy for a re-build and re-curve. Some of the experts on some other forums will lead you south. With some mods, you obviously could map a timing scheme that will make it run best performance and economy wise. I couldnt tell you how to set up a cent and vaccum adv and achieve the optimum, so I opted to go centrifugal only, then completly electronic. But this is just my opinion. Aloha