Spanish 48 webers

[Gregs]

How good are the SP 02 webers compared to the original?
My 2.1L pinto has always run on 45 dellorto and is very strong.(over 200 bhp)
I am building a bigger motor and have bought a set of 48 for this.
ive tried to run them on my current motor but car is 20 kw down on power.
It is very lean low down and has a flat spot right up to about 3500 rpm and then gets better but wont rev past 7000rpm.

weber has 40 chokes
f16 emulsions
55f8 idles
45 pump jets
100 bowl bleed
180 air
160 main

Any advice would be greatly appreciated

[Dyno]

My experiences with 48 DCO are about the same, your are probably not correct tuned yet but even if they are, they seems to be too big for a Pinto, never being as good at low end as the 45 Weber (or in you case Dellorto). The only way to make them work (or a least do something) is fitting small chokes. So small you are back where you started. All DCO's I've ever seen coming in for a rebuild had machined small chokes.

[rick deregus]

i would stick with the 45s torque is better

[Gregs]

Would you stick to 45 carbs even with a 2.3 L ?

[Graham]

if your after every last hp at the top of the rev range, 48's will be good, but probably only 2-3bhp more than 45's.

the head will only flow so much air, doesn't matter much what size bottom end its fitted to, which is why in general 2.3's dont make much more hp than 2.0/2.1, what the bigger capacity does though is bring the power lower down the rev range.

i recently reworked a 2.3 pinto, in my opinion the mapping session was cut short, so perhaps we didnt get the best from it, but thats almost beside the point. I changed the exhaust to one proven to be very good, i increased the size of the throttle bodies, reworked the head to get more flow, we ended up with exactly the same power as before, although torque was up and at lower revs, so i only saw 208bhp but at a mere 6500 rpm

[Graham]

i would stick with the 45s torque is better

i wouldn't expect better torque in terms of more, but i would expect a better more users friendly power curve

[Dyno]

I've been using one and the same head on a 2,3 ltr and later after planing a very little on a 2,0 Ltr. 2,3 Ltr made 210 Bhp, 2,0 Ltr 193 Bhp but 2,3 Ltr had a complete different torque curve, a lot better to drive compared to the 2Ltr. All with HT1e cam.

By accident, the head is currently back in(whole 2,0 Ltr) and was last time fitted with RL31, making 189 Bhp. I've made small changes to the head, hoping to see little over 190 Bhp

All with Weber 45 mm

[rick deregus]

could you try a 41mm choke in the 45s

[Graham]

you could but i suspect it wont work very well, if the choke size is too close to the throttle size you have no venturi effect, and it wont draw fuel through the mains properly, rather like having a choke way way too big

[Forest_rallying]

When I finally get my car finished off I am going to try 36mm chokes on my engine that's fitted with Italian 45's with a GTS4 cam and see how the it pulls. I also have a Spanish set of 45's to try with 38mm chokes off another engine.

[Miniliteman]

How good are the SP 02 webers compared to the original?
My 2.1L pinto has always run on 45 dellorto and is very strong.(over 200 bhp)
I am building a bigger motor and have bought a set of 48 for this.
ive tried to run them on my current motor but car is 20 kw down on power.
It is very lean low down and has a flat spot right up to about 3500 rpm and then gets better but wont rev past 7000rpm.

weber has 40 chokes
f16 emulsions
55f8 idles
45 pump jets
100 bowl bleed
180 air
160 main

Any advice would be greatly appreciated

First of all, did you compare the power figures (45's and 48's) on the same day?
How did you test the power with the 48's? Rolling road?
What cam did you use?
The maximum chokesize for a set of 45's I would use is 39 mm.
If you still want to ahead with the 48's try fitting F11 tubes, 60F6 idles, 50 pump jets and reduce the back bleed considerably.

[Gregs]

The test was done on a rolling road 2 days apart.The 45 have 38 chokes. My cam is a Rc31 ( Kent).

[Forest_rallying]

If I am not mistaken the KC RC31 is a Full Race cam with over 320 degrees and very high lift. Getting driveability and jetting correct is going to be a challenge for the most experienced Rolling Road operator whether it be 45's or 48's.

[Gregs]

Yes it’s a full race car!