Technical What sized carburettors are used on a 1500?

[Chas Uno]

Hi All,

Quick question here. Could someone tell me what size Weber carburettors are used on the 1500 models? I'm assuming the standard carb was a twin choke Weber (DMTE? DMTR?), but does anyone know what sized chokes (barrels) are used? i.e Weber DMTE 28/32 with the 28 and 32 denoting the choke/ barrel sizes?

Many thanks

 

[H105Daz]

34 DATR
primary secondary
Venturi ..........23.0mm .................26.0mm
Main jet .........1.07 .................... 1.30
Air corr' ..........1.60 ....................1.50
Slow running .... 0.47 ................... 0.70
Emulsion tube .. F30 .................. F30

 

[Chas Uno]

Many thanks for the response

So the venturi's on the X19 carb are 23mm and 26mm? Reason I'm asking is that I've bought an X19 1500 engine and am hoping that a rejetted Uno SX Weber meant for the 1301cc engine can be used. The Uno uses a Weber 30/32 DMTE 12/150 carb with venturis of 19mm and 23 mm, so it looks like it will struggle with the bigger engine

Are there any good places to find the bigger X19 carbs?

 

[jimbro1000]

The 1300 X1/9 used a 32/34 DMTR - even that was sizably bigger than the one on your Uno - but then again it developed 75bhp and not 60bhp. It takes more than just the carb though. The X1/9 camshaft was quite aggressive (by Ford standards it would be classed as a fast road spec). The 1300 Uno engine was also based on the 1500 X1/9/strada engine not the 1300 X1/9 engine. It has the stroke of the 1500 but not the bore, this may also sound like technicalities but it makes a big difference to how the engine performs - in this case the 1300 Uno engine was more economical but wouldn't rev like the 1300 X1/9 engine used to.

 

[Chas Uno]

The 1300 X1/9 used a 32/34 DMTR - even that was sizably bigger than the one on your Uno - but then again it developed 75bhp and not 60bhp. It takes more than just the carb though. The X1/9 camshaft was quite aggressive (by Ford standards it would be classed as a fast road spec). The 1300 Uno engine was also based on the 1500 X1/9/strada engine not the 1300 X1/9 engine. It has the stroke of the 1500 but not the bore, this may also sound like technicalities but it makes a big difference to how the engine performs - in this case the 1300 Uno engine was more economical but wouldn't rev like the 1300 X1/9 engine used to.

Many thanks for this information. It sounds as if the 1300 X1/9 engine was the same spec as that fitted to the 127 1300GT and the 128 3/P?

From what I've read in the Fiat literature the original 1300 S/ SL/ SX Uno engine produced 68bhp, but this was slightly detuned for later SX models to produce more torque at the expense of power. Weirdly, I have a road test of an earlier 70 SL that didn't perform as well as another road test I have of a later 70SX!

Regardless, the reason I was asking about 1500 carburettors was that I was buying a 1500 X1/9 engine for my Uno 70SX. Luckily, I managed to buy an X1/9 carburettor as well when I went to collect the engine so hopefully all will be fine on the fueling front.

You can see more details of my purchase here:

https://www.fiatforum.com/uno/220198-i-can-has.html

Thanks again H105DAZ and Jimbro1000 for your help

 

[jimbro1000]

Just remember that power is not the answer to everything, torque is far more useful, not just peak figures either.

You are quite right about the engine configurations, the 128 engine was the one originally used in the X1/9 but was never used in the Uno (by Fiat at least).

Good luck with the new engine and carb.

 

[Chas Uno]

Just remember that power is not the answer to everything, torque is far more useful, not just peak figures either.

You are quite right about the engine configurations, the 128 engine was the one originally used in the X1/9 but was never used in the Uno (by Fiat at least).

Good luck with the new engine and carb.

Cheers!

And I agree totally with your sentiment regarding power not being the answer to everything. My thinking was that I could have tuned the 1300 engine I already have to make more power but at the expensive of moving torque and power peaks further up the rev range, or I could fit a bigger engine and leave it in standard tune. Much like VW did when they dropped the Audi 80 based 1.6 and 1.8 engines into the mk1 and 2 Golfs. Neither engines were especially powerful for their size, but with a good spread of torque and a light(ish) body shell the original Golf GTi's were amazingly tractable cars with plenty of low down power and torque. This is similar to the effect I want to re-create by fitting a 1.5 litre engine into my Uno.

Now I just need the weather to stop playing artic winters so I can actually go outside and do some work on my cars...