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To many CFMs


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Well Im learning without haveing spent much money, for the first time, lol. I was trying to use a Rochester 36mm 2 barrel on a 1.8, not going to work. The vacume drop at just a crack is enormous, causing the rotating assembly to lag several seconds. So I am researching the proper CFM. In my search I found a few Carbs that might work, all are Weber designs or manufactured. I hope to find if a Weber 32/36 is tuneable for such a small engine.

I've been told that I should have around 130 CFM, 32/36 is around 300, progressive. I found a 32/32 from a Fiat, just hard to get rebuild kit.

I should mention the Rochester that I have is 278 CFM non progressive, might be the difference, all at once. Just playing with it and hoping to hear some feed back. Thanks.

Edited by machineit
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Port the heads and open up the exhaust alot all that air and fuel have to have somewhere to go And then you have to burn all that extra air and fuel so a ignition upgrade would be needed Maybe give the air and fuel more time to mix before hitting the botom of the plenum by using a thicker carb spacer would help the factory spent a lot of time and money getting things right they have people who do nothing but study this stuff the problem with that is we want more MORE bigger stronger faster in order to get more you have to redesign the entire system not just the intake if the ports in the head can't take flow then how can it suck in all the extra fuel if the exhaust is the same size how will it get the extra burnt gasses out of the motor I personally I'm not smart enuff to redesign the system but I did study how other people did it on rubies and other motors to come up with what I have now I added 1" spacers between the head and the manifold and another 1" under my throttle body full port job on my heads and I opened up the exhaust a little and upgraded my ignition system I am still using the spfi system though and have no real flat spots I gained about 20% more power but it was as a system using proven methods not just changing one or 2 parts in the system I've seen guys run 4 barrels on Volkswagen's so I know it can be done just have to match the flow on the rest of the systems or use a sensible progressive carb like most people already do

 

Personally judging by the quality of your work I would love to see you go hog wild on this thing I mean come on let's see some porting and polishing and some sweet custom exhaust work to match

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Some good food for thought, I have another set of heads that I started on, shaved .08" off them, New valves, seats and guides, suppose I could write a program to remove some material from the intake and exhaust, port. Wouldn't cost me anything just a little time. Thank you for the input and encouragement. In the meantime I found a 2 barrel Holly from a 79 Jeep 4 cylinder, ordered a rebuild kit too. Just want to drive it at this point, I've had it almost a year and been working on it here and there, however, would be fun to build a high output E 82 for it, if I do my research as you say, I could make it a little screamer, hog wild ????

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Port the heads and open up the exhaust alot all that air and fuel have to have somewhere to go And then you have to burn all that extra air and fuel so a ignition upgrade would be needed Maybe give the air and fuel more time to mix before hitting the botom of the plenum by using a thicker carb spacer would help the factory spent a lot of time and money getting things right they have people who do nothing but study this stuff the problem with that is we want more MORE bigger stronger faster in order to get more you have to redesign the entire system not just the intake if the ports in the head can't take flow then how can it suck in all the extra fuel if the exhaust is the same size how will it get the extra burnt gasses out of the motor I personally I'm not smart enuff to redesign the system but I did study how other people did it on rubies and other motors to come up with what I have now I added 1" spacers between the head and the manifold and another 1" under my throttle body full port job on my heads and I opened up the exhaust a little and upgraded my ignition system I am still using the spfi system though and have no real flat spots I gained about 20% more power but it was as a system using proven methods not just changing one or 2 parts in the system I've seen guys run 4 barrels on Volkswagen's so I know it can be done just have to match the flow on the rest of the systems or use a sensible progressive carb like most people already do Personally judging by the quality of your work I would love to see you go hog wild on this thing I mean come on let's see some porting and polishing and some sweet custom exhaust work to match

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