Dual or single plane?

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68fastback

68fastback

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I am new to the performance world and wanted to know what the difference is between a single and dual plane intake. Why is it not recommended to use a single plane on the street?
 
Single plane intakes kill off bottom end power and add power on top. Dual plane intakes are more street friendly because they match the cam power ranges better for street applications.
 
Yeah, dual planes offer a wide range of throttle response especially more at lower rpm (where most street driving occurs) whereas single planes are more for wide open throttle and really perform well in the upper rpm range. Unless you`re doing more racing than street cruising I would suggest going with a dual plane intake.
 
Torque converters with higher stalls make up for the rpm range on single plane intakes during launch when racing.
 
If the car spends more than half the time at the track, a single plane would be better with a converter that has a high stall? Would that work on the streets at all?
 
Oh, Spokane, that's right. Duh! Anyway, I use an Edelbrock Performer Dual-Plane. It plays very nice on the boulevard. You could move up to the RPM version for the track. It's still very streetable.
 
I have a LD340 dual plane but I dont know if that is the best choice. I am willing to sell the LD340 and buy a better one if there is that big of a difference.
 
The LD340 is essentially a performer RPM and works great. There is a draw back with the LD340 though, if you want to run a mechanical temp gauge. There is not a spot for the probe to thread into on the front of the intake. The performer RPM and performer RPM airgap are good dual purpose intakes.
 
Robzilla said:
The LD340 is essentially a performer RPM and works great. There is a draw back with the LD340 though, if you want to run a mechanical temp gauge. There is not a spot for the probe to thread into on the front of the intake. The performer RPM and performer RPM airgap are good dual purpose intakes.
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so its not worth selling the LD and buying another intake?
 
In my opinion, unless you are going to use a mechanical temp gauge, use the LD340.
 
Robzilla said:
The LD340 is essentially a performer RPM and works great. There is a draw back with the LD340 though, if you want to run a mechanical temp gauge. There is not a spot for the probe to thread into on the front of the intake. The performer RPM and performer RPM airgap are good dual purpose intakes.
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Yeah, I just bought mech gauges, and when I got to the water sensor..wtf?
 
With the right combination dual planes are just fine for the track,i've gone 11.0's running one,know guys that are running single planes that wish they were running that quick..
 
dont forget about tunnelrams they are truly awsome when setup properly on a motor that can take it with the right gearing and converter, i have run one and a friend of mine runs one and they are great!

stroked340 you should realy try a tunnelram i bet you would never look back if you did and took your time geting it right!
 
On the LD340 I bought someone drilled and tapped for a mechanical gauge on the left of the thermostat to run both gauges.
 
68fastback,

The main difference in a single plane and a dual plane is the path to the cylinder heads, Dual planes are usually a less direct path and therefore are better suited to wide rpm range torque production at lower rpm(under 6500). Single planes are designed to produce maximum power in a smaller rpm range usually at a higher rpm at the expense of some lose of lower end torque.

Unless you have a high compression, large cam, high rpm engine, your usually better off with a dual plane, That's what I'm running. And the higher torque is especially important with a heavier vehicle. Torque is also what you feel when you mash the gas... HP is a function of torque x rpm... But we wont get into that.:read2:

Hope this helps,

Bjkadron
 
Who needs torque when you have a 5000 stall! Although probably not that streetable.8)
 
bjkadron said:
68fastback,

The main difference in a single plane and a dual plane is the path to the cylinder heads, Dual planes are usually a less direct path and therefore are better suited to wide rpm range torque production at lower rpm(under 6500). Single planes are designed to produce maximum power in a smaller rpm range usually at a higher rpm at the expense of some lose of lower end torque.

Unless you have a high compression, large cam, high rpm engine, your usually better off with a dual plane, That's what I'm running. And the higher torque is especially important with a heavier vehicle. Torque is also what you feel when you mash the gas... HP is a function of torque x rpm... But we wont get into that.:read2:

Hope this

Bjkadron
Click to expand...

thank you so much. All the help is so great. All of the help you guys give is great.

Thank you

brad
 
To expand on Bjk's response... it's two sections that make or break an intake. The plenum, which is the area directly below the carb/throttle body and the port runner, which is the passage from the plenum to the head. Very basiclly, the smaller the plenum, and smaller and longer the runners, the more responsive and more low-rpm oriented and intake will be.

Single plane intakes were the original designs for most V style engines for years. The plenum is usually larger (at least in the performance designs), and the runners each feed one cylinder and all directly come off the plenum. The plenum allows the air/fuel mix to bend easier and enter each runner. However, too big is worse than too small in terms of plenum volume because when they are too large for a given package the air will slow down, the fuel can fall out of suspension, and the engine loses torque. This is why most single planes have the reputation for feeling sluggish. The plenums are larger and designed to move air better at faster rpm rates. So they will make more power over all in many cases, but the power curves tend to be more peaky, rather than flat or gentle curving toqrue curve of a street engine.

Dual planes combine ports that enter the plenum area, and they usually divide the plenum in half so the engine "feels" like it has a smaller plenum volume, however they also use larger runners to let it breath better at higher rpms and carry that power higher. The best dual plane factory style intake is the '71-'72 Thermoquads. Those are what the discontinued LD340 was designed after. They feed 4 cylinders, two from each side, into 1/2 of the plenum. Same design is now used in the Performer Edelbrocks, Stealths, and various others. The RPMs have a larger runner cross section, and a slightly larger plenum area to extend the power range up higher than the Performer with no loss of low end. Because the dual planes tend to idle better and make a flatter torque curve, they are the primary intake for the street. However, when you start looking at a complete pacakge, if a single plane intake ca work, it will almost always make more power. But the whole car has to be able to make use of the power they create in whatever rpm that happens.
 
moper said:
To expand on Bjk's response... it's two sections that make or break an intake. The plenum, which is the area directly below the carb/throttle body and the port runner, which is the passage from the plenum to the head. Very basiclly, the smaller the plenum, and smaller and longer the runners, the more responsive and more low-rpm oriented and intake will be.

Single plane intakes were the original designs for most V style engines for years. The plenum is usually larger (at least in the performance designs), and the runners each feed one cylinder and all directly come off the plenum. The plenum allows the air/fuel mix to bend easier and enter each runner. However, too big is worse than too small in terms of plenum volume because when they are too large for a given package the air will slow down, the fuel can fall out of suspension, and the engine loses torque. This is why most single planes have the reputation for feeling sluggish. The plenums are larger and designed to move air better at faster rpm rates. So they will make more power over all in many cases, but the power curves tend to be more peaky, rather than flat or gentle curving toqrue curve of a street engine.

Dual planes combine ports that enter the plenum area, and they usually divide the plenum in half so the engine "feels" like it has a smaller plenum volume, however they also use larger runners to let it breath better at higher rpms and carry that power higher. The best dual plane factory style intake is the '71-'72 Thermoquads. Those are what the discontinued LD340 was designed after. They feed 4 cylinders, two from each side, into 1/2 of the plenum. Same design is now used in the Performer Edelbrocks, Stealths, and various others. The RPMs have a larger runner cross section, and a slightly larger plenum area to extend the power range up higher than the Performer with no loss of low end. Because the dual planes tend to idle better and make a flatter torque curve, they are the primary intake for the street. However, when you start looking at a complete pacakge, if a single plane intake ca work, it will almost always make more power. But the whole car has to be able to make use of the power they create in whatever rpm that happens.
Click to expand...

Thank you! That's what I was going to say but I was short on time and was approaching "nerd territory" very quickly! Not to mention it was late and I was having a hard time getting a coherent thought pattern :) Glad to hear their is another Technical nutball on here! And I say that with the best possible connotations.
 
Not just one but a bunch here I've seen but I've learned when moper talks you better listen he knows what he is saying.
 
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