Upgrading stock carb vs Aftermarket
 

OK guys i keep having a debate with my brother. He says that by porting out the stock carb, allowing for larger primaries and what not, it will do the same job as lets say a dual webber, or any other reputable aftermarket carbs. Now since i have never dealt with carbs in my life, i can’t really say why he is wrong, other than knowing he must be, because evry first gen i see with Serious mods, all ditch the stock carb, and have an upgraded one put on.

Basically, why is a aftermarket webber or any other brand better than a stock carb ported / larger primaries, and what not. What are the limits to the stock carb, even if you modded it to the fullest extent, and why can it never be better than a good aftermarket carb?

HE has a 260HP first gen, 13B, no turbos, and i keep telling him, ditch the stock carb (modded mind you)and put in a nice aftermarket one, as im sure it will help him with HP, or at least attribute to a more responsive motor.

thanks.

I haven't heard of anyone getting more flow out of the stock Nikki than Sterling while maintaining good drivability. Sterling's carbs are rated at 465 CFM at 1.5" Hg. A Weber 48 IDA is over 600 depending on how it's configured, and there are plenty of even bigger carbs around, especially of the square-bore 4bbl variety. In terms of airflow capability, a Nikki will never be able to compete with these.

Do you need more than what a Sterling carb can provide? Depends. If you're running a stockport 12A, maybe not. A bridgeport 13B, on the other hand, wants more than even a 48 IDA according to Racing Beat's dyno testing.

There's also the problem of the stock intake manifold, which is apparently quite restrictive (but I haven't seen any actual flow numbers on it).

I need to see this :scratch:

there's no way he's getting that kinda power from a normally aspirated 13b, especially with the stock carb.

I call BS on the HP numbers also. Maybe 160 more likely.

That just made my day! 260HP on a N/A 13B? Whats he smoking?

I have no experience with the stock carb, except before i switched to my weber. ( i have a IDF, not IDA not much difference)
I didnt like it of course, until after it was rebuilt. The driveablity was great. Loved it.
But then i dropped a Big Street port in my car and my weber, etc.
Of course the 'steetability' of my car has gone way down. I have to set my idle once the weather changes slighty. Sometimes change jets, of course you really mess with jetting once you first get the carb or swap motors.. (those are the down sides.)
Up sides are great power up high, the airflow capabilities of the weber are second to none.. Which i love this. But i hate all the tuning i need to do sometimes, and the poor driveablity.

That's my two cents.

My Weber DCOE drives as well as a stock carb except for the lack of a choke and the bog if you try to floor it from idle (you'll have the same problem with a 4bbl with mechanical secondaries). It just has more power and it's easier to tune.

Maybe he means 260 HP at the flywheel? That's around 220 to the wheels, which is quite believable if he's got a big port and a good exhaust and intake setup. With a stock carb, though? Not so much.