I'm running a stock 12a, and I want to make more power than I am with the stock nikki carburetor. I've been looking into the weber 48 IDAs, though I've heard they're very hard to get it to run correctly with the stock port. I do plan on porting (complete bridge port) the engine as soon as the motor blows (350k original miles, itll probably last a good while longer.) What carb make the most power for the time being while being easy to use and reliable?

 

Also looking to get rid of the rats nest

 

There's lots of mods for the Nikki, that are much better than messing with a different brand. A little research will get you all you need.

Why delete the rats nest?

 

Hands down the best carb is a modified nikki. A big weber or weber clone will also work but will need more care in tuning. The traditional 4 barrels are not very well suited for the rotary (Holley/Edelbrock/etc). The best weber setup is the dual DCD 36 but its not available new anymore.

 

The best is a stock NIkki.
It starts in all conditions, even in winter, even at different altitudes, it has the best mileage, it passes emissions, it gives relatively good torque, low noise and is very flexible.
If you can compromise and lose some of those advantages for a slight power increase, you can use an aftermarket carb and delete the rat's nest. The carb alone is useless; you need to upgrade a lot of thing, and it is NEVER plug and play, you need to do some tuning.

I went for a Webber 45 DCOE, I love the sound of it, the quick response, the additional power, the relative simplicity to change the jets BUT I invested also into:
- Racing Beat complete exhaust
- fuel pump and fuel regulator
- Intake manifold
- AEM Uego AFR gauges and sensor
And my fuel consumption went to the roof, not to mention the noise of that thing (but I think it is glorious), and in cold winter days it is nearly impossible to start.

 

Agreed, stock Nikki with the rat's nest is best for performance, fuel economy and, since you probably already own one, your wallet.

 

Nikki.

 

So don't delete the rat's nest? Is there a decided power difference with and without the rat's nest?

 

Now power difference with or without rats nest.

 

Any reason not to remove the rat's nest then? Easier starting, torque, or fuel efficiency?

 

Rats nest can be problematic when the solenoids and vacuum hoses start to deteriorate. Yanking it just simplifies your whole engine bay and reduces the number of potential failures. But you won't pass emissions if that's a concern.

 

All those solenoids control fuel and air delivery during warm up to optimize fuel efficiency and power.

Delete the rat's nest and expect harder starts, rougher idle, lower fuel efficiency, increased emissions and uneven accelerator progression, especially until the engine reaches normal operating temperature.

 

Okay, so to build off that, would anything change if you were running a bored out nikki? Would you get an advantage from deleting the rat's nest if you're modding the carburetor and changing jetting?

 

You have to start with the exhaust mod first before you do anything other. Spent your money racing beat in Anaheim and feel the free breathing of your engine.😜

 

I agree with RX7fb spirit r on starting with the exhaust. I have been racing RX7's for 20 years. Using an unmodified Nikki, a stock 12A with stock exhaust manifold, but cats removed makes about 110-115hp (assuming engine in good shape). Stock 12A with RB street header is around 130hp. YMMV depending on dyno type and conditions, but that has been approximately my experience.

I don't know how the Holley works on the street, but my direct experience is that it is not ideal for road racing due to the configuration of the floats (even after changing to center pivot). It seems like it should work OK on the street, since you should not be cornering hard enough to cause the float problem. Not sure if others have experienced an increase in HP with the Holley on a stock 12A, especially if the exhaust has not been modified.

My rats nest is long gone and have no issues as such in the racecar. I never drove the car as a daily driver without the rats nest, so don't know how removing it affects "street driveability".

 

I'm not sure we defined best, but here is my $2

the Nikki
Drive-ability: excellent
Emissions/Economy: being a stock carb its best here
Cost; excellent, it came with the car
Power: good, it works well on a stock 12A with a stock or mild exhaust, which is what most people seem to be running

Weber IDA
Drive-ability: it needs tuning, but can be excellent
Emissions/Economy: being a big 2 barrel vs a 4 barrel means its probably not going to be as good as the nikki
Cost: bad, carb is not too bad, but once you jet it, its on par with EFI
Power: best. its flexible and will work on everything from a stock 12A to a 13B peripheral port.

Holley
Drive-ability: bad, needs tuning, and will not run around hard corners no matter what
Emissions/Economy: if you fiddle with it long enough economy can be ok, but even the big three couldn't get a Holley to pass emissions
Cost: worst. its more expensive than the weber (new parts vs new parts)
Power: on the big port engines its always 10-15hp less than the weber, and you can' change the venturi so it doesn't scale like the weber either.

Weber DCOE, its like the IDA, except the wrap around manifold that is typical puts the powerband in the mid range, which makes it a nice street carb, but peak power is in the middle too. the accelerator pump is a PITA on these...

 

You forgot the moded nikki works better with 12 A street and bridge port in cold aria and make it very streetable and economic. The nikki was constructed especially feed rotary no other carb was that.
The most 12 A BP power you will get with the Holley.The most 12A PP power with the Weber.

 

I feel all of it, im open headers lol

 

in my experience rats nest removal just makes the car smell more, definitely doesn't start any harder or idle any rougher

 

How does a Dellorto compare to the others?

 

Dellorto = DCOE, carb is a little different, but wrap around intake dictates power band