Single Solex VS Webers on 1600 TI

[magista]

I have a question regarding the merits (or not) of converting the single Solex carb on my 1600 TI to dual Webers (or even a single downdraft Weber). Doesn't seem like this would be too difficult (coming up with a manifold might be) but would the gains be worth it or would there be any real gains in power?

I'm not saying that I will do this, I'm just kinda of just thinking out loud at this point.

Any thoughts?

[Curtis]

Sorry, I can only comment on downdrafts and full race prep experience. If you have the early Solex with big primary and secondary barrels, then in my opinion the 36DCD weber isn't going to make any more outright power than the Solex. If you have the (I think later solex) with a smaller secondary bore, then a 36/36 weber would probably make a noticeable difference in outright power. In a modified street application, the weber is certainly more tuneable in the low and mid range. I am going to play with a 36DCD some more on the dyno this winter, but expect I will still be running the solex next year. FYI many downdraft webers off fiats and the like will bolt on to the stock Solex manifold without an adapter.

While there is nothing wrong with a Solex downdraft, side draft DCOES are hands down, absolutely the way to go when the budget (or rules) allow.

[magista]

Thanks for the info.

This would be for street application. I have 40DCOE32s on my Berlina and I love them. The TI is coming with a slightly modified 1600 (1750 pistons have been installed).

So how hard is a side draft conversion? I assume the manifold for a 1750/2000 engine will not fit a 1600.

Once again I'm just thinking out-loud and may be just fine with the single Solex.

[JoeCab]

Damian,

Both conversions (to single DGV or dual DCOEs) will be a big improvement. I'm pretty sure the DCDs are gone (new) so I wouldn't consider those an alternative. The DGV will be much smoother and easier to tune, and the DCOEs will give the power and throttle response they are famous for. It all comes down to how you plan to use the car.

(assuming all new carbs)

Dual DCOEs - around $1,500. Finding a 1600 manifold will not be hard as they are not useable for the Spica-to-Webers conversion on 1750 or 2000 motors.

DGV and air cleaner - around $500

Joe

[Andrew]

For sure I'd drive it awhile with the setup it has, assuming it works OK, and see what you think, before deciding whether to swap. Single-carb setups on relatively large engines can result in very smooth, torquey power (witness most classic American iron). And the carb setup is a breeze compared to Webers. The Webers will certainly snort and snuffle in an exhilerating way, and give better top end, but may not be better at the bottom end. Plus you'd be doing the setup for a pretty odd engine (nonstock approx. 1700 cc). I've driven a number of single-carb 1300 Giuliettas recently and was really impressed, compared to my dual-carb Super.

Also, the 5.12 with this larger engine will probably really wind out, assuming you can get the column shift to work adequately. The car ought to feel like a rocket, at least in off-the-mark acceleration.

Has anyone calculated what displacement you get on a 1600 stroke crank with 1750 pistons, which is what this car has?

Andrew Watry

[papajam]

1649cc with standard 1750 pistons; 1690cc with oversize (81mm) 1750 pistons.

[magista]

Thanks for all the feedback.

This is just me thinking out loud and I will probably end up being just fine with the set up it has now. I already have a hotrod holligan mobile (the Berlina) so a stock, or semi-stock TI will be fine I'm sure.