jetting for a 1750

[figleaf11]

I'm putting a 1750 into my Giluia and need to rejet my webbers set up for my old 1300. Currently using:
40DCOE27
120 main
F11/50
30mm choke tubes (venturi)
air correction 195
emulsion F16
Using 10548 euro cams

What would be the best starting places for a 1750 street engine? I see Centerlines recommendations but was wondering if the real world is different.
Thanks guys,
Ralph

[101/105guy]

I would be interrest to know also.
Just started running the 1750 in my super and bolted the 1600 Webers up as is. Same specs as yours. Low speed runs fine, but I know that I shoud rejet for higher RPM use.

[alfavirusnz]

Venturi should be 32mm(should have been 28mm with 1300)
Aux venturis 4.5
mains 130
air correctors 200
F9 emulsion tubes
idle jets 50F8
accel pump jets all same -35`s
float needle valves all same-150
starting jets generally all 65F5`s.
Float level setting is 7.5mm.
Hope this helps.

Richard J

`65 Giulia Ti, `69 GT Junior, `74 GTV 2000, `76 Alfetta GTV, `77 alfetta GTV, `84 GTV6

[papajam]

And for another slightly different setup, the following is what I ended up with on our stock Series 1 Euro 1750 with 10548 cams;

venturi - 34mm
main - 135
air - 160
emulsion - F9
idle - 50F14
sparkplugs - Champion C57

These settings returned about 30mpg if driving in economy mode and high teens/low 20s on the track.
Keep in mind that driving style, type of fuel, climate and altitude will play a role in your setup.

[alfavirusnz]

Jim wouldn`t that have made it a bit flat at low and up to mid range-airspeed in my experience is important through these carbs-the euro cams (std where I come from) with std carb settings give very nice torquey engine with broad power curve and excellent steady speed economy of high 30`s/early 40`s at 100kph/60mph. The 1750 engine is particularly economical, better than 1600 and far better than 2 litre.

Richard J

`65 Giulia Ti, `69 GT Junior, `74 GTV 2000, `76 Alfetta GTV, `77 Alfetta GTV, `84 GTV6

[Gary Williams]

You can also download the ever popular -- and very helpful -- Dave Andrews carb setup software here: Carb software

[alfavirusnz]

The thing is though why reinvent the wheel when all the factory settings are available enabling you to capitalise on all the development work the original engineers put in, and lets not forget we are dealing with some of the top engineers of their day with incredibly vast experience in this field.
If your engine is factory setup why waste time and money-it`s not as if these cars were trying to be clean, they were during this time setting for best engine performance from idle speed to max revs.

Richard J

`65 Giulia Ti, `69 GT Junior, `74 GTV 2000, `76 Alfetta GTV, `77 Alfetta GTV, `84 GTV6

[Gary Williams]

Not sure who you're directing your comment to Richard. The factory recommended setup is great for a box stock engine. On the other hand, the Andrews software allows you to decide if you're after economy, maximum performance, or something inbetween, then provides a recommended setup. The software gives options depending on the driver's requirements.

[alfavirusnz]

Yes I`ve seen and used the software and it is a ready and rough guide only speaking as a former Eurocar garage proprietor who has spent many hours setting up Webers, Dellortos, Solexes and mechanical fuel injection systems such as Kugelfischer, Lucas and Bosch K-both bog std road,and racing cars. The software is a reasonable place to start but isn`t Ralph`s (figleaf11) car a standard 1750 so why confuse the issue.
Bog std euro spec = bog std euro carb settings developed by experienced and brilliant factory engineers-you are not going to better them regardless.
A good road car and an occassional track car needs as broader torque and power curve as you can give it that`s one of the reasons why Alfas have always been very quick point to point cars but very seldom the quickest outright accelerators.

Richard J

`65 Giulia Ti, `69 GT Junior, `74 GTV 2000, `74 Alfetta GTV, `77 Alfetta GTV, `81 Giulietta,`84 GTV6

[papajam]

Quote:

Originally Posted by alfavirusnz Bog std euro spec = bog std euro carb settings developed by experienced and brilliant factory engineers-you are not going to better them regardless.

[figleaf11]

Thank you sooooo much fellows, got a good handle on it now. Yes it is a stock 1750,converted from spica to weber w/10548's. Nothing special just a good street engine which should really perk up my giulia TI.
Ralph

[alfavirusnz]

That`s what I have in my `65 Giulia Ti Ralph, except obviously the 1750 was Euro spec 2nd series (10548`s std). Often when the engines are traded here the carbs get sold seperately -very popular conversion on classic rally cars, classic road cars and Lotus 7 replicas. As a consequence the previous owner has obviously bought athe 1750 without carbs and then bought a set of Dellortos for it but unfortunately off a Australian specced Alfetta GTV so have wrong era carbs. Car had been sitting for a number of years so the carbs were well and truly gummed up.
I`m just finishing off body (just made and installed new front floor and new middle and outer sills)-still have bottom of rear guards to do from behind whell arch.
After repairing the original Dunlop brakes and having a structurally sound car again I`ve driven mine on the road a couple of times and I reckon I don`t need a gearbox -5th is fine it`s so lowly geared. 1st is essentially redundant and I can easily take right hand corners in 4th at 5mph and still pull away like a train. Have you found that?
My car was originally 1600 ( floor change).

Richard J

`65 Giulia Ti, `69 GT Junior, `74 GTV 2000, `76 Alfetta GTV, `77 Alfetta GTV, `81 Giulietta 1.8, `84 GTV6

[figleaf11]

Richard, I hope to fire up the engine today so have'nt driven it yet. Car was euro import to here w/1300 and single carb. I picked up a complete 1600 weber set up and ran it with the 10548's I installed. Ran well but little torque as usual for 1300. Have installed a berlina diff which was tall for the 1300 (went like hell after 3500 tho) It should do fine with 1750. Just gotta sort out the jetting etc. Many thanks for the insight/info.
Ralph

[la_strega_nera]

Thought I'd drag this one back up - going to be re-choking and re-jetting mine - now has a heavily ported head, stock sized exhaust valves with 45* seats and 1mm oversize intakes with 45* seats, cams are 11.7mm with 246* duration (intake) and 10.8 with 242* duration (at 0.050thou).
Compression is about 10.5ish :1
Re-choking up to 34mm chokes in 40mm webers - I'm guessing that the jetting will be somewhere around 135 mains and 180 air correctors?

[la_strega_nera]

End result after a dyno session was
mains 135
air correctors 200
F9 emulsion tubes

Curiously, the s1 1750 carbs on my car were 130 main, 185 airs...