Hello all,
Those of you who've been there and done it, just how cramped is the twin side-draft set up on an early Beta coupe with the old style radiator? The big disadvantage is always said to be that one of the carbs is basically pulling hot air, whereas the other is not facing the radiator so gets cooler air, making the tuning extra difficult. To complicate matters further, my car is an 1800 with the shorter block, so I'd be looking at a GC manifold for an upright Fiat 131 engine with an adaptor plate to correct the angle, and I can't picture how bulky that set-up would be. What I'm wondering is whether I'd be able to fit any kind of thin airbox between the original radiator and the carbs, so that I can draw cool air from elsewhere and feed both carbs at the same temperature. I don't really want to change the radiator and distributor if I can avoid it.
Alternatively, how well do the down-draft set-ups fit with a block-mounted distributor and the original radiator? I'm still tempted by the 2xDCNF option because I reckon it would look a lot less conspicuous and would probably fool a French MOT-tester, especially if I could get a sensible-looking airbox like the one sold by Chad at the Monte Hospital (anyone know if that would fit under the bonnet of a coupe?)?.
Any thoughts/advice much appreciated.
Cheers,
Andy
DCOE or DCNF
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Todd D.
Re: DCOE or DCNF
Hi Andy,
I have been there and done that. I purchased a set of 42mm DCNF's plus a Guy Croft manifold to mount on my Scorpion. Since the Scorp was being restored at the time I thought I would mount them on my 77 1800 beta coupe. I really didnt have any problems other than rigging up a throttle linkage that used the original throttle cable. I had to cut about 10mms off the air cleaners so they wouldnt touch the hood and used special flat head alan key 'furniture nuts' to hold the air cleaners together.
The whole set up was removed and is now in the Scorpion.
I tried to mount a set of 40mm DCOEs in the Beta coupe but finally gave up . I used very short Piper intake trumpets but that left side carb was always an inch from the rad. I built a cold air box out of aluminium and sucked cold air from just right of the rad. In that area there is a metal plate that has 2 metal screens . I removed the screens and used it as the intake.
I had problems with the dipstick hitting the manifold and the manifold hitting the alternator. My next step was to re-engineer the tensioning bar for the alternator. The manifold was a straight shot Guy Croft ,but in hindsight alot of the problems would have been solved if I had the manifold that is angled off to the left a bit.
In the end I had the original 32DATRA rebuilt and installed in the coupe.......and it runs great. The lesson I learned is that unless you go full out and install long duration cams with increased compression and free flow exhaust., going the dual weber route is not really the best option in a stock 1800 motor.
K&N make a filter and housing for DCOEs that is very thin (1-1/4 inches thick) and could be used with out hitting the rad.
Good luck
I have been there and done that. I purchased a set of 42mm DCNF's plus a Guy Croft manifold to mount on my Scorpion. Since the Scorp was being restored at the time I thought I would mount them on my 77 1800 beta coupe. I really didnt have any problems other than rigging up a throttle linkage that used the original throttle cable. I had to cut about 10mms off the air cleaners so they wouldnt touch the hood and used special flat head alan key 'furniture nuts' to hold the air cleaners together.
The whole set up was removed and is now in the Scorpion.
I tried to mount a set of 40mm DCOEs in the Beta coupe but finally gave up . I used very short Piper intake trumpets but that left side carb was always an inch from the rad. I built a cold air box out of aluminium and sucked cold air from just right of the rad. In that area there is a metal plate that has 2 metal screens . I removed the screens and used it as the intake.
I had problems with the dipstick hitting the manifold and the manifold hitting the alternator. My next step was to re-engineer the tensioning bar for the alternator. The manifold was a straight shot Guy Croft ,but in hindsight alot of the problems would have been solved if I had the manifold that is angled off to the left a bit.
In the end I had the original 32DATRA rebuilt and installed in the coupe.......and it runs great. The lesson I learned is that unless you go full out and install long duration cams with increased compression and free flow exhaust., going the dual weber route is not really the best option in a stock 1800 motor.
K&N make a filter and housing for DCOEs that is very thin (1-1/4 inches thick) and could be used with out hitting the rad.
Good luck
-
andy b
Re: DCOE or DCNF
Thanks for the useful info, Todd. You conclude that, without other modifications (cams, exhaust, compression, etc.), any twin Weber setup is not really worth it, which I'm willing to believe. But does that apply, in your view, to both US-spec and Euro-spec 1800s? I have a European 1800, and the standard 9.8:1 compression and 120hp seem fairly good. Do I still need other engine mods to get a good result from twin carbs? Also, thinking about the GC downdraft manifold you used, I assume that the engine in a Scorp is inclined in the same direction as the coupe, ie. it leans towards the exhaust side by about 20deg, right? Haven't seen a Scorp since about 1978...
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Todd D.
Re: DCOE or DCNF
Hi Andy,
I have mounted the 42mm DCNF carbs back on my Scorpion along with a Guy Croft Monte Carlo manifold. As far as the 20 degree angle tilt, it is the same as in the Beta 1800 and will fit fine. The only problem I had was the aircleaners touched the hood a bit. I just cut @ 1/2inch off and they were fine.
I have finally got the Scorpion on the road last week and can make a back to back comparison with my 1800 beta coupe.
The coupe has standard 8:1 compression with stock cams and a 4-2-1 Ansa header. With the 42mmDCNFs mounted it ran well but required some finesse when accelerating. If you just stood on it it would bog down and slowly catch up. I really noticed the dual carbs at high speed. It seemed to just keep accelerating...and even when you let off the gas it would keep accelerating untill all the excess fuel was used up. I would sum it up by saying that the engine breathed really well, but the standard cam cannot process the huge amount of air and fuel going through the engine. I should mention that I repeatedly pulled the plugs and checked them. That includes using Gunsons Colortune ( a great little tool) and the carbs were jeted corectly . The engine was new with good compression and I still got fuel in the oil.
Now the same carbs and manifold are on the Scorpion. It has 10:1 compression, plus Kent 40/80/80/40 long duration cams and a free flow Monza quad tip exhaust. This engine hasn't even begun to wear itself in and I can feel the difference with the cams. It revs to 5000 so fast Its scary. I need to keep an eye on that. It pulls well from low revs and drops back to idle very quickly. I thought I would have trouble with it idling but it purrs like a kitten at 600RPM. So... I guess give the DCNFs a try. It cant hurt and they sound great but keep an eye out for bore washing if you have the stock Cam.
Good luck.
PS. I have a cold air box for DCNFs from Chad. It fits the Scorp but I dont think it would fit under the hood of a Beta Coupe.
I have mounted the 42mm DCNF carbs back on my Scorpion along with a Guy Croft Monte Carlo manifold. As far as the 20 degree angle tilt, it is the same as in the Beta 1800 and will fit fine. The only problem I had was the aircleaners touched the hood a bit. I just cut @ 1/2inch off and they were fine.
I have finally got the Scorpion on the road last week and can make a back to back comparison with my 1800 beta coupe.
The coupe has standard 8:1 compression with stock cams and a 4-2-1 Ansa header. With the 42mmDCNFs mounted it ran well but required some finesse when accelerating. If you just stood on it it would bog down and slowly catch up. I really noticed the dual carbs at high speed. It seemed to just keep accelerating...and even when you let off the gas it would keep accelerating untill all the excess fuel was used up. I would sum it up by saying that the engine breathed really well, but the standard cam cannot process the huge amount of air and fuel going through the engine. I should mention that I repeatedly pulled the plugs and checked them. That includes using Gunsons Colortune ( a great little tool) and the carbs were jeted corectly . The engine was new with good compression and I still got fuel in the oil.
Now the same carbs and manifold are on the Scorpion. It has 10:1 compression, plus Kent 40/80/80/40 long duration cams and a free flow Monza quad tip exhaust. This engine hasn't even begun to wear itself in and I can feel the difference with the cams. It revs to 5000 so fast Its scary. I need to keep an eye on that. It pulls well from low revs and drops back to idle very quickly. I thought I would have trouble with it idling but it purrs like a kitten at 600RPM. So... I guess give the DCNFs a try. It cant hurt and they sound great but keep an eye out for bore washing if you have the stock Cam.
Good luck.
PS. I have a cold air box for DCNFs from Chad. It fits the Scorp but I dont think it would fit under the hood of a Beta Coupe.
-
Todd D.
Re: DCOE or DCNF
Hi Andy,
I have mounted the 42mm DCNF carbs back on my Scorpion along with a Guy Croft Monte Carlo manifold. As far as the 20 degree angle tilt, it is the same as in the Beta 1800 and will fit fine. The only problem I had was the aircleaners touched the hood a bit. I just cut @ 1/2inch off and they were fine.
I have finally got the Scorpion on the road last week and can make a back to back comparison with my 1800 beta coupe.
The coupe has standard 8:1 compression with stock cams and a 4-2-1 Ansa header. With the 42mmDCNFs mounted it ran well but required some finesse when accelerating. If you just stood on it it would bog down and slowly catch up. I really noticed the dual carbs at high speed. It seemed to just keep accelerating...and even when you let off the gas it would keep accelerating untill all the excess fuel was used up. I would sum it up by saying that the engine breathed really well, but the standard cam cannot process the huge amount of air and fuel going through the engine. I should mention that I repeatedly pulled the plugs and checked them. That includes using Gunsons Colortune ( a great little tool) and the carbs were jeted corectly . The engine was new with good compression and I still got fuel in the oil.
Now the same carbs and manifold are on the Scorpion. It has 10:1 compression, plus Kent 40/80/80/40 long duration cams and a free flow Monza quad tip exhaust. This engine hasn't even begun to wear itself in and I can feel the difference with the cams. It revs to 5000 so fast Its scary. I need to keep an eye on that. It pulls well from low revs and drops back to idle very quickly. I thought I would have trouble with it idling but it purrs like a kitten at 600RPM. So... I guess give the DCNFs a try. It cant hurt and they sound great but keep an eye out for bore washing if you have the stock Cam.
Good luck.
PS. I have a cold air box for DCNFs from Chad. It fits the Scorp but I dont think it would fit under the hood of a Beta Coupe.
I have mounted the 42mm DCNF carbs back on my Scorpion along with a Guy Croft Monte Carlo manifold. As far as the 20 degree angle tilt, it is the same as in the Beta 1800 and will fit fine. The only problem I had was the aircleaners touched the hood a bit. I just cut @ 1/2inch off and they were fine.
I have finally got the Scorpion on the road last week and can make a back to back comparison with my 1800 beta coupe.
The coupe has standard 8:1 compression with stock cams and a 4-2-1 Ansa header. With the 42mmDCNFs mounted it ran well but required some finesse when accelerating. If you just stood on it it would bog down and slowly catch up. I really noticed the dual carbs at high speed. It seemed to just keep accelerating...and even when you let off the gas it would keep accelerating untill all the excess fuel was used up. I would sum it up by saying that the engine breathed really well, but the standard cam cannot process the huge amount of air and fuel going through the engine. I should mention that I repeatedly pulled the plugs and checked them. That includes using Gunsons Colortune ( a great little tool) and the carbs were jeted corectly . The engine was new with good compression and I still got fuel in the oil.
Now the same carbs and manifold are on the Scorpion. It has 10:1 compression, plus Kent 40/80/80/40 long duration cams and a free flow Monza quad tip exhaust. This engine hasn't even begun to wear itself in and I can feel the difference with the cams. It revs to 5000 so fast Its scary. I need to keep an eye on that. It pulls well from low revs and drops back to idle very quickly. I thought I would have trouble with it idling but it purrs like a kitten at 600RPM. So... I guess give the DCNFs a try. It cant hurt and they sound great but keep an eye out for bore washing if you have the stock Cam.
Good luck.
PS. I have a cold air box for DCNFs from Chad. It fits the Scorp but I dont think it would fit under the hood of a Beta Coupe.
-
andy b
Re: DCOE or DCNF
Tod,
Thanks very much for taking the time to answer all my questions. Think I'll give it a try!
Regards,
Andy
Thanks very much for taking the time to answer all my questions. Think I'll give it a try!
Regards,
Andy