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I’ve stripped out the original air filter box and support bracket and fitted trumpets and k&n pan filters to twin Webers dcoe 40’s. I removed the bracket which supported the old filter box (bolted to the engine mounting) because it got in the way of the k&n’s. Great induction and noticeable power improvement but I’m concerned that the carbs may need support.

I’m sure that many other series 2 spiders have been converted to after market filters and trumpets. should I be concerned?
 

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Welcome to Alfabb. You need to install the support bracket. The carburetor mounts are not sufficient to support the carburetors without the bracket. Among other reasons, the support is needed to keep the fore and aft carburetors from moving with respect to each other and adversely affecting synchronization. I am assuming you are using rubber mounts.

If induction noise is the goal, then the K&N filters will accommodate you. Trumpets and K&Ns sucking in hot air from the engine compartment are not likely to improve power and more likely to decrease it. The OEM setup has been proven to be very good and better than most alternatives. There has been lots of discussion on this topic over the years. I encourage you to use the search capability to locate old threads on this subject.
 

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Welcome aboard, you will find the crew at Alfabb to be probably the best advice available for our sports cars. If you were running the standard airbox, but have since removed it, there will be problems. Centerline offers aluminum support brackets or you could install heli coils into stripped internal threads in your air box.
 

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Discussion Starter #4
Welcome to Alfabb. You need to install the support bracket. The carburetor mounts are not sufficient to support the carburetors without the bracket. Among other reasons, the support is needed to keep the fore and aft carburetors from moving with respect to each other and adversely affecting synchronization. I am assuming you are using rubber mounts.

If induction noise is the goal, then the K&N filters will accommodate you. Trumpets and K&Ns sucking in hot air from the engine compartment are not likely to improve power and more likely to decrease it. The OEM setup has been proven to be very good and better than most alternatives. There has been lots of discussion on this topic over the years. I encourage you to use the search capability to locate old threads on this subject.
Thank you Rich, your advice is much appreciate!
 

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Welcome aboard, you will find the crew at Alfabb to be probably the best advice available for our sports cars. If you were running the standard airbox, but have since removed it, there will be problems. Centerline offers aluminum support brackets or you could install heli coils into stripped internal threads in your air box.
Thank you Cabman, I shall seek out the Centerline solution and search for past threads on the subject. It’s reassuring that folks like you and Rich are out there for good advice.
 

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Here you go. You'd be amazed at what Google will do.

 

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TB, you're welcome. I used to have K&N oval filters on my '78 Spider. Flat head screws were needed to connect the mounting plate to the support bracket to avoid interference with the filter. Unless your filters are significantly different, you should be able to get the support bracket to fit without too much difficulty.
 

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Here you go. You'd be amazed at what Google will do.

Many thanks Samakijoe. I joined Alfabb only yesterday and have been bowled over by the help and experience I have been offered from yourself, Rich and Cabman. I have searched Classic Alfa (UK) and Alfaholics (UK) websites for the support plate but no luck so have just placed my order with Centerline.
 

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It is easy enough to take some strapping steel and make your own if you have a vise, drill and some vise grips. You put the strapping steel in the vise and twist it 90 degrees. Drill a hole down on the engine side and loosely bolt it in. Run the other end up to your plate between the K&N filters and the carb. Mark the holes and bend the carb side for your bolt and drill. You need the support bracket eventually or your gas will vibrate too much in the carbs. I ran a while without the support when I was in college, but got smarter. It's pretty quick to do and you can do it in a couple hours with steel you can find at almost any hardware store. You just need to remember to twist the steel away from the linkage. Actually, I think it was my Stanford Engineering Dad who showed me the trick. Your K&Ns aren't original so what the heck. Make your own bracket
 

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It is easy enough to take some strapping steel and make your own if you have a vise, drill and some vise grips. You put the strapping steel in the vise and twist it 90 degrees. Drill a hole down on the engine side and loosely bolt it in. Run the other end up to your plate between the K&N filters and the carb. Mark the holes and bend the carb side for your bolt and drill. You need the support bracket eventually or your gas will vibrate too much in the carbs. I ran a while without the support when I was in college, but got smarter. It's pretty quick to do and you can do it in a couple hours with steel you can find at almost any hardware store. You just need to remember to twist the steel away from the linkage. Actually, I think it was my Stanford Engineering Dad who showed me the trick. Your K&Ns aren't original so what the heck. Make your own bracket
I like that a lot Dr G - both the idea for making the carb support with strap steel and that you got smarter after college! I guess you can congratulate your tutor for a job well done ?
 

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Also the fact as a very poor college student my Dad helped me out. God rest his soul. Merritt Carden helped me out as a poor college student many times too, at non Alfa of Palo Alto rates, LOL. Miss them both.
 
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