45 DCOE Progression Holes & Fiat T/C Engine
Discussion
Good evening, every day is a schoolday for me and "wot I learned yesterday" is that Weber 45 DCOE are all not equal, they differ in several ways including the number of progression holes they have. I apologise for this but the existance of different numbers of progression holes in what I thought were all the same carb was new to me.
When I rebuilt my Morgan some 18 years ago I transplanted the 2l engine from my Fiat Mirafiori 131 Sport (Guy Croft tuned Stage II) into it, it had a single downdraft carb on it and I bolted a pair of twin Weber 45 DCOE to it and took it to the local Weber Concessionaire to jet and tune it on his rolling road and I've done so every year since then. I don't race the car, I merely use it on the road. Around 4 years ago I was told that the alloy on these carbs had gone porous and so I bought a new set and replaced them using the same person to set them up. Anyway, I had my car rolling road tuned again yesterday at a different place (the previous dealer closed up this Christmas) and was told that the flat spot I have at low revs is not down to tuning but is due to my carbs only having 3 progression holes. I checked and my previous carbs also had 3 progression holes.
I done some looking on the Web and note that the 45 DCOE 152G can come in 3, 4 and 5 hole versions with the higher number to specifically to eliminate this low rev problem, but I can't find out which would be more suitable for my car. Guy Croft's Fiat T/C book doesn't note these differences, I note that Webcon sell a 45 DCOE kit for Fiat T/C's but they don't state how many progression holes the carbs they supply for this have. I've found nothing else on other various Fiat forums (should this be fora?).
Can anyone help me here please? I would much appreciate it.
Many thanks in advance.
Stoat
When I rebuilt my Morgan some 18 years ago I transplanted the 2l engine from my Fiat Mirafiori 131 Sport (Guy Croft tuned Stage II) into it, it had a single downdraft carb on it and I bolted a pair of twin Weber 45 DCOE to it and took it to the local Weber Concessionaire to jet and tune it on his rolling road and I've done so every year since then. I don't race the car, I merely use it on the road. Around 4 years ago I was told that the alloy on these carbs had gone porous and so I bought a new set and replaced them using the same person to set them up. Anyway, I had my car rolling road tuned again yesterday at a different place (the previous dealer closed up this Christmas) and was told that the flat spot I have at low revs is not down to tuning but is due to my carbs only having 3 progression holes. I checked and my previous carbs also had 3 progression holes.
I done some looking on the Web and note that the 45 DCOE 152G can come in 3, 4 and 5 hole versions with the higher number to specifically to eliminate this low rev problem, but I can't find out which would be more suitable for my car. Guy Croft's Fiat T/C book doesn't note these differences, I note that Webcon sell a 45 DCOE kit for Fiat T/C's but they don't state how many progression holes the carbs they supply for this have. I've found nothing else on other various Fiat forums (should this be fora?).
Can anyone help me here please? I would much appreciate it.
Many thanks in advance.
Stoat
Boggs couldn't sort mine - they just put richer idles in which made it worse.
It was Peter Burgess who used to post on here who made a massive improvement after over 3 hours on the rolling road and numerous dyno plots and tweaks - proper old school, solder, jet drills the whole painstaking process. If I took a carb'd car anywhwere it would be to Peter, he's a true gent as well.
OP - he's in Alfreton, Notts.
It was Peter Burgess who used to post on here who made a massive improvement after over 3 hours on the rolling road and numerous dyno plots and tweaks - proper old school, solder, jet drills the whole painstaking process. If I took a carb'd car anywhwere it would be to Peter, he's a true gent as well.
OP - he's in Alfreton, Notts.
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