I don’t know, I want to go faster, i have a stock 650 and thinking to put a bigger carburetor, a Solex pbic 34 might be the one since it can be found quiet cheap and I don’t want to spend a small fortune on a carb. A faster cam, suitable for daily running so not the wilder one and maybe bigger valves, combined with my 500 lighter flywheel and sport exhaust I think little car is going to kick a little and maybe reach 30hp. May I hear you opinion on valve sizes again for daily use, which camshaft to choose and what about this solex pbic 34 carb?
Tuning Looking to go faster
- Thread starter gordinir8
- Start date
Currently reading:
Tuning Looking to go faster
the hobbler
Distinguished member
- Joined
- Jul 25, 2012
- Messages
- 4,406
- Points
- 1,107
Hi Thomas:-- I will send you my thoughts on the tuning of the '126'engine---both the 594cc and 652cc versions. It will answer a lot of your questions. If you can find a 34PBIC complete and in good condition, well done (a manifold is still available for it), but parts might be a problem. An alternative is a Weber---the 34ICH. This will use the PBIC manifold (on a 3 port head), can be obtained BRAND NEW and with a bit of 'fettling', the choke can be made to work exactly the same as the standard IMB carb on the 500
Seems to me that you pretty much got a handle on the formula for upping the hp whilst keeping the car road suitable. In my opinion you only need to up the size of the inlet valves to achieve a better inlet/exhaust ratio. Porting the head can help a lot and you might consider a light skim on the head or at least run a thin copper head gasket. The Solex 34 PBIC carb was used on the top of the range Giannini cars. I too was interested in getting my hands on one so looked on the usual sites. Seems they were used on a range of cars including the Willis Jeep. Looking at some of images I could see that some of them were not configured to easily fit the Fiat. I saw one on Italian eBay that had come from a Fiat 500 and they were asking €700 for it.
Well first of all there is a Solex 34 PBIC about 90 kilometers away from me for 60 euros and looks from the pictures in pretty good shape, price is low but i will know in the morning if it is still available. Now i will agree about the bigger valves but if i remove the head to rework it, it is a good idea to replace the cam also, along with the carb i think it will give me some pretty good results.
Thanks Tom, already read it and it is a good guide, i am not looking for anything different than this i think, most tricky part is the cam installation and alignment but nothing that can't be done, those guys at Blitz racing have detailed info about how to do it. Another thing that considers me is the ignition system and the heat of distrubutor and coil because of their location in the engine so Nanoplex is also in my list but last, i am just not sure if this system has a kind of electronic advance or not. A few pictures of a polished and smoother head might also help.
So i still looking for the solex 34 pbic, But i have other alternatives in mind like the Weber
30DGS from panda (which is smaller than solex but also just a little bigger than 28IMB so i am not sure which one is better for my engine. I have also noticed that 30DGS comes from many cars except panda, like from Citroen, are they identical except the jets of course? Do i need to source one from Panda?
30DGS from panda (which is smaller than solex but also just a little bigger than 28IMB so i am not sure which one is better for my engine. I have also noticed that 30DGS comes from many cars except panda, like from Citroen, are they identical except the jets of course? Do i need to source one from Panda?
A traditional upgrade carb conversion is the Weber 30DIC , also the Holley version. A twin choke downdraught carb that was originally fitted to the Fiat 850 Sport coupe and Spyder. Later came the Panda 30 twin choke carbs, the Weber DGF and Solex C30 DID/1. You can buy manifolds for these carbs off the shelf and the latter two are already jetted for an uprated 650 twin cylinder engine.
Found at my local junkyard a weber 30DGS1 / 250 from Citroen zx. I think DGS is panda 30 carb but i am not sure if the ventury size match with the one from panda. What you think? It also has an electric on/off of switch.
Hi Thomas, I have run one engine with a Panda 30 carb (Weber 30 DGF) for some time and can testify to the simplicity of the fitting and of the driving experience. With a low level mount the DGF will sit well below the engine bay roof, my engine has a mount from 500 mania in Italy. The main advantage is that the twin venturi are both 23mm, but because the carb is progressive you only use the second venturi when pressing hard with your foot, thereby causing lower fuel consumption while cruising gently - or not!!! The standard jetting will work straight away but you can improve this as the jets are easy to change.
Ian.
The one I have found is from Citroen GS NOT ZX I I wrote above. Looks pretty similar but I am not sure if it will work as good as the panda carburettor. Not sure if ventury is the same. Anyway looks like a good carb and I have the feeling that it might be more economical in fuel use if you hold your leg. Trying to locate also a panda carb but in a badget since I also need a camshaft plus the labor cost to mod the head. So trying to keep overall cost as low as possible.
The problem you may have by going for a random carb is that you will not be able to get a manifold to fit it and be faced with the prospect of having one made or doing it yourself.
Finally decided to go for a panda carb. If anyone knows the exact p/n and if there is early and late version. I am a little confused with those because there are also DGF that comes from fiat 126 BIS, something I want to avoid. I have seen lot of variations like 1/251 to 1/254 and all those types according to Axel Gerstl site comes from BIS Don't want to buy something that has smaller Venturis for instance.
Yes as you say the ones fitted to the Bis had restricted 19mm venturis. I have examples of both the carbs, Weber & Solex, that were fitted to the Panda 30 plus a couple of the Weber 30DIC carbs if you need any pictures or information.
Yes that is correct. The Panda 30 carbs have the 23mm venturis. On the early Weber 30DIC carbs they are 21/23 and then 23/23 on later carbs. Considering the 30DIC carbs were only fitted to the Sport Coupe and Spyder they had many revisions from 1 to 11 then there was a Weber 30DICA which was fitted to the American versions. These were a bit of a nightmare to me as they had all the whistles and bells demanded by the US emission rules. Of the DIC range I prefer the simplicity of the early models.
Problem is that BIS weber 30 carb also has 23 23 stamped on so i am not sure if this number has to do with venturi size or not. Anyway i have asked a couple of sellers if their carbs come from Panda or not.
I am wondering if they just used the same main body casting for the Bis. The Weber Venturi sizes are quoted in the relevant Haynes manuals then shown on the carb bodies as you highlighted. Shown below are a 500 and a 126 carb as well as a Solex which is still bolted to the Panda 30 manifold. I noticed that there are three Solex carbs on Italian eBay not badly priced.
If it is as you said, then panda and bis have the same Venturis at 23 mm, but in the real world they don't! I think that number 23 is stamped either if it is 23 or 19mm and differences can only be seen by eye if someone has both carbs in hand. I might ask Axel Gerstl about it.
No because on some of these carbs the Venturi is removable like the 40DCOE. I do not have a Bis manual or carb to hand to check such things.
