attn: weber experts

[carrerarsr65]

i need help going to weber carbs but i started to find there a different types of 40size webers, ida etc. is there any performance advantages btween the different models, thanks again guys for everyone advice. the engine is a 3.0sc row also looking for any cam suggsetions also this will be used for autox and overall thrashing!

[KTL]

Performance Oriented

[Joe Bob]

Webers are old aren't made anymore. They have flat spots due to no accel pumps. If you insist on carbs consider new PMOs (updated Weber replicas).

The 964 or 20/21 cams are nice upgrade.

Take a look at the rules you will be competing under. Many engine mods put you in a class that is high dollar. Better to consider suspension and handling mods first.....along with some driver seat time.

[SCrescue]

Weber 40mm IDA 3C carbs "Made In Italy" (or PMO as Joe Bob suggests) are what you should look for if you want to build a good setup for a mostly street driven car. Look for 46mm carbs if you are interested in a more track dedicated setup. You will need to buy manifolds matched to your 3.0 ports, as original manifolds had significantly smaller port sizes. You also need to consider backdating your exhaust at the same time to maximize the benefit of carbs, SSI's are a great option.

CIS pistons are a notoriously limiting factor for racing purposes, but are acceptable for mid level street performance with a decent cam profile such as 964. I went with DC-19 (re-profiled SC cams) from Dougherty. They are basically 964 cam profile with a tad more lift.

Good luck!

[1QuickS]

IDA and IDAP Webers are good, IDTPs are inferior for larger main venturis like you need for your car. IDTPs will have a flat spot (lean mixture) at transition onto the mains.

All Webers have accelerator pumps.

I modify IDTP carbs to eliminate the flat transition but it is an addition to other service packages I offer.

Also, I modify 40mm throttle bores to be anything from 40mm to 46mm so sourcing a set of 46's may not be necessary. If you increase engine performance much your engine will want venturis that are too large for 40mm throttle bores.

If you don't have Webers already then the expense of buying used Webers and refurbishing them may well be equal to that of buying a PMO setup.

[Joe Bob]

You're right was thinking of the two barrel models.

[T77911S]

Originally Posted by KTL

Performance Oriented

this is an INCREDIBLE site!

i wish this was around when i had webers because i learned by trial and error, and some things i thought i new i found out were wrong based on this site.
mainly that the throttle plate is a "mechanical" setting and once set, it is left alone, IE, its not really for sttetting the idle, the air bypass screws do that.
i wish there was more info like this on carbs. even though i dont have them anymore, i really enojoyed reading and learning about them.

BTW, he explains the differneces in the webers.

[KTL]

Originally Posted by T77911S

this is an INCREDIBLE site!

i wish this was around when i had webers because i learned by trial and error, and some things i thought i new i found out were wrong based on this site.
mainly that the throttle plate is a "mechanical" setting and once set, it is left alone, IE, its not really for sttetting the idle, the air bypass screws do that.
i wish there was more info like this on carbs. even though i dont have them anymore, i really enojoyed reading and learning about them.

BTW, he explains the differneces in the webers.

Agreed. That website is a wealth of information. Plus you have "the man" Paul Abbott himself from Performance Oriented right here in this thread to get some feedback if need be. Man really knows his craft when it comes to the Weber style carbs. He's provided us some fantastic info over the years.

[T77911S]

he is the man
he was going to hook me up with some more reading but i never heard back and i did not want to bother him over that.

[1QuickS]

I like being "bothered"; it helps keep me fresh! Plus, I get to visit with fellow enthusiasts!