In the beginning, when I put all this on Desktop Dyno, it was saying I would be making 360hp@6000 and 365ft-lb@4500
If I put in a single plane intake... when I put in a dual plane, it drops the hp by 20 and the torque by 10.
Here's the setup I was planning on running:
*327
*Vortec heads modded for lift
*XE268H cam .477/.480 DUR: 268/280 1600-5800RPM
*TBI bored to 48mm

I'm not sure about the intake though.. if I use a single plane manifold, I get the power above.
But if I use a dual, I get these numbers:
340hp@5500 and 355ft-bl@4500

So pretty much my question is.. will a single plane work with vortecs on a daily driver? O should I just go with a dual plane performer?

 

i thought a single plan was suppose to give u more top end power, which the dual plan was better for low end

 

You sound as if you have something against using a single plane manifold with that engine? If it's going to make significantly more power why not use a single plane, I'm sure many can be adapted to vortec heads and there's probably some out there too just check around the usual places like jegs and summit. If you're running TBI a single plane shouldn't be a problem at all for your engine combo.

 

If it were me I'd seriously consider looking at gas prices and torque converter/hook instead of simulation software (unless virtual 4-stroke). If you drive a lot, full weight, auto, gas prices high, cruise with it, and have a relatively tight converter, it's no question. Go dual plane. If you want the most hp, lighter vehicle, stick, don't care so much about gas milage, or have a higher stall converter then go single plane. Another reason to go with single plane is the fact that you can get away with a slightly smaller TB and make more hp with it than you would be able to with a dual plane. I would go with an RPM high-rise intake. These manifolds are solid and just as good if not better than most any wet-flow intakes on the market for a 200-400hp engine. Seriously it's almost the best of both worlds. I don't really understand how they designed the divider but it's just enough to share the plenums. Seems to work very well without any moving parts.

 

I was thinking one of those Performer RPMs, but I need it to fit under the stock hood. I guess the only way to get around that is a drop-base air filter.

 

Mine fits under the stock hood with a non drop and the huge Holley adaptor on top of the RPM.

 

Fact? Who told you that?

Going with a smaller carb on a single plane is an attempt to make it more streetable. By putting on a smaller TB/carb/whatever, you're effectively reducing the amount of airflow to the engine. That simply defeats the purpose of a single plane.

Hot rodders back in the day would do that. Run on the street with a 600 cfm carb, drive to the strip, throw on the 780 and WHHHAAAAAA!!!!!!!!

This may not seem like a big deal if you're spending a lot of time on the street because you're not using the upper RPMs a lot. But if that's the case, why use a single plane anyway? The whole purpose of a single plane (EFI or Carb) is to allow more airflow at upper RPMs. But sacrifices low, and sometimes even mid RPM torque.

Putting a smaller TB on a larger plenum will only be a crutch to make it streetable. It makes as much sense as using a 1200 stall TQ and a 2.73 rear end behind 450 HP at 6500 RPMs.

 

BTW, did you know that a TPI setup is effectively a single plane intake. Tell me, is it fact that what you say about a single plane allowing more airflow at upper RPMS but sacrificing low/mid torque is true? Who told you that?
In general a single plane has very short runners but still there are zero degree's of freedom between intake valve openings. This effectively means that with a single plane (common plenum) has a constant air draw from both throttle bores. A dual plane seperates the engine effectively into 2 4 bangers and takes advatange of both pressure waves to make a motor more VE (more torque). This alone accounts for why it's fact that you can flow more air through 2 bores so close to each other on a constant draw of air than you could alternating between them. Also a single plane intake almost always has a larger plenum volume making a larger TB almost useless.
If you want to learn more about intake design and effective power ranges and WHY/How they work, take a class in automotive engineering or get a hold of a few good books.

 

How can you hate engine building when it seems that the only engine you've "built" so far has been on a computer simulator.

 

LOL.. yeah... I guess I hate the planning aspect of it so far. Thanks for all the help. I'm sure hoping I'll be able to fit all that under the stock hood. I'll give it a shot and if it doesn't wrok..I'll go with that drop-base filter.

I'm holding you to it Chuck!
I sure hope your right.

 

There is a calculaton you use to determine an engines airflow requirement. Carb manufacturers suggest that you add 20% to your engines required airflow when running a dual plane. This is why an engine like edelbrocks performer RPM package uses a 750 CFM carb instead of a 600 that is more inline with what the engine actually consumes. Not nessicary with a single plane.

Since we are limited by a 2" bore throttle body that does not flow all that well the single plane has a definate advantage.

There is something else that people keep missing... that is dual planes were originally designed for carbs as a band aid to thier method of metering fuel. Yes its true that when you have a small diameter runner you will increase velocity at lazy low rpm speeds and pick up a little low end torque but at the same time you are creating a restriction in the upper rpms. TBI cars do not need this band aid to help them meter fuel (and thus improve drivability). If you need the extra 10 ft/lbs at 1500 rpm... thats only the difference between a 3.4 and a 3.5 : 1 gear ratio. On street tires most people dont have enough traction to put it all to the ground anyway. Look, its not like you have a 1.8 litre puddle jumper... you have 5+ litres... maximizing low end torque should not be your objective. Its power to weight ratio that makes your car faster. Let that engine spin into the upper RPM's where it will make power and dont restrict it with a dual plane. I ran both intakes on the same mild 350 in the same car. There were no advantages in drivabiliy with the performer. I was traction limited with both intakes. The Weiand street ram 7525 pulled stronger up top.

The car had a 3.50 rear gear (ford 9" rear) 700r4 with a 2050 vortec v6 s-10 converter, home ported 70's smog cylinder heads, 219/227 @.050 hyd roller cam with .480 lift. Based on the one track outing I had with that combo it was making around 330-350hp.

 

whats the difference betweent the 305 tbi engine and the old 327?

 

I've experienced it.

Quote:

In general a single plane has very short runners but still there are zero degree's of freedom between intake valve openings. This effectively means that with a single plane (common plenum) has a constant air draw from both throttle bores. A dual plane seperates the engine effectively into 2 4 bangers and takes advatange of both pressure waves to make a motor more VE (more torque). This alone accounts for why it's fact that you can flow more air through 2 bores so close to each other on a constant draw of air than you could alternating between them.

You're forgetting that the OTHER advantage of a dual plane is the longer runners which build velocity and 'tune' the RPM range (similar to TPI. More so than a single plane). That's why they build more torque down low. Faster cylinder fill at lower RPM. Granted you'll lose some upper RPM HP because of the narrower runners and the decrease in overall flow due to the multiple angles. Plus the CFM to each cylinder is decreased because (as you said) the each cylinder only gets the flow of one bore (when speaking TBI).

A single plane increases the available flow to each cylinder, effectively increasing upper RPM HP. The other advantage is the 'straight shot' the air flow has into the intake port. It reduces direction changes, which decreases turbulance, But since there's a loss in velocity, the low RPM torque suffers. That is true regardless of TBI or carb.

Quote:

Also a single plane intake almost always has a larger plenum volume making a larger TB almost useless.

How does it make it useless? When using a single plane you want the largest available flow. That's the whole reason behind using a single plane in the first place. To use a smaller TB is useless. It defeats the purpose of even having a single plane.

Quote:

If you want to learn more about intake design and effective power ranges and WHY/How they work, take a class in automotive engineering or get a hold of a few good books.

Take your own advice. I have real world experience with these two intake manifolds. I've run each on the same engine. Granted it was carberated, but that doesn't dismiss the basis of how each works. And the engine responded accordingly.

Using EFI doesn't change the characteristics of how an engine uses airflow, especially when using TBI. Saying "TBI isn't effected as much" is total wrong. Regardless of how fuel is admitted into the engine, airflow is still airflow. It's still changed by the different type of intake design.

 

AJ, I don't need to take my own advice. I'm already doing it and it's why I replied telling you to do the like. EFI and carb is not the same. Carb is a different animal, pulling the fuel into a wet-flow is no where near the same as injected regardless of TBI or TPI. EFI in general dismisses all carb applications an "experience" since it eliminates the whole delta pressure between the low and high sides of a carb venturi. Don't even get me started.
Intake design isn't based on just effectiveness. It's also production processes and profit. Single planes only take advantage of a peak runner pressure at that back of the valve at high rpms making it more VE in a higher rpm range. Dual plane has two power peaks but when the plenum is shared you need to supply enough air to keep the "middle grounds" from slopping off. THIS is why a single plane can get away with a smaller intake. A dual plane intake with a rev-kit could show the duel torque peak if and only if the plenums are seperated completely. This is old school, new stuff like the RPM have a sized divider to make the manifold act like a single plane or a dual plane depending on variables like air velocity and volume/revolution. It's amazing what you subject yourself to when you take carb technologies and keep them in the back of your mind instead of thinking with them! Next step is dual runners, variable length runners, variable duration cams, no cams, variable plenum, and multi fuel compatible engines. Get a book, read, get an SAE magazine that talkes about specific topics but ONLY after you read the basics about intake design and take some dynamics and fluids classes.
For TBI, I'd go with a single plane only because most if not all TBI motors have no problem with low end torque and besides, you guys have v8's, forget about low end and think about making the car faster. It's not a towing compitition, it's a race!!!!
Only thing TBI and carbs have in common is the wet-flow intake. Nothing else can even be considered without taking out the significant variables (venturi design, temp, etc.)

 

There are quite a few things that people 'think' happens, and what actually happens. The only thing that changes from carb to TBI is HOW THE FUEL IS ENTERED INTO THE ENGINE. CFM is CFM. AIR FLOW IS AIR FLOW. You need to go back to the basics and learn, how the FUEL gets into the engine has very little effect on the basic principals of how INDUCTION works.

You're so quick to critisize carbs that you overlook the fact that everything on an engine still works the same. The basic principals don't change. Using TBI doesn't allow you to bend the rules. Single planes are MUCH MORE SENSATIVE to proper CFM from the carb or TB. They're harder to tune and have a much more narrow usable RPM range. They are not practical for the average person.

He asked which he should go with. Based on the cam he's using, and using Vortec heads, he should go with a dual plane. It better matches his other components. You get so wrapped up in your opinion that you overlook what would be best for the person asking the question.

 

Read my 1st reply to the post, then read yours. , lol
air flow is air flow and cfm is cfm....fuel goes in the same way blah blah blah. I guess it never occured to you that carbs are more sensitive because they can't be too big else fuel atomization is an issue. TBI doens't have this problem because it's a form of INJECTION. At low engine speeds a single plane drawing from both tbi bores will atomize the fuel better than a carb of equal size. This is why you can't be so stupid as to saying a single plane with a carb needs cfm and is more sensitive when the carb is out of the question. Only thing in common is wet-flow. Even then I can assure you that a 4 barrel carb doesn't come close to having the same fuel/air distribution issues as a 2 barrel TBI does. It's a game, a wild game.
Dual planes are great for a carb or a street motor with a mild cam and looking for a low/mid range boast in torque. If you've got a sports car with good gears in the back with a high stall converter, go with a single plane. TBI will give you great throttle responce (another short comming of mismatched carbs) and plenty of low end. There have been countless posts about this topic and listen to the guys that have run with both before you make a decission. Do a search for TBI single plane and it should give you some good reads. Don't go over to the carb board asking for manifold selection. Like AJ said, they'll start asking you why you don't have carb or jump to conclusions and tell you to be real careful about what size carb you install. It's all useless information since a carb is more picky.
AJ, I don't get wrapped up in my opinion. I just answer the question with TBI facts, not carb facts. Go back to school if you're having such difficulty understanding the more complicated principals of TBI induction. Basics are great for understanding the basics, but to understand why and how some stuff works you can't skip class!
As far as harder to tune. . I think a single plane is easier to tune. Single planes let you tune for one torque peak and almost always has a more gradual slope from off idle. Different length runners is one BIG change but also the divided plenums. You'd be amazed what tuning can be done when you split the v8 into 2 4 bangers and keep it EFI.

 

Jon, MeThinks that you are arguing with a cinder block. . . Check out his argument with me about pinning rocker studs, his premise was apples and oranges. The guy is blind, must be the bricks he has for retinas.

RBob.

 

Who's talking about fuel atomization? That's a whole other subject. I'm talking about the design and intentions of the two types of manifold designs.

Dual planes are set up to increase low/mid RPM torque. We both can agree on that correct? It's basically the same attempt as TPI (just using that as a relative example so others can relate). The runners are designed to be as equal in length as possible to equalize the pulse waves to the cylinders. You can see that by looking at which of the runners go to which cylinders.

The divided plenum is needed to further equalize the amount to each cylinder. What this does is create a broader (more usable) torque curve under peak torque. A great advantage for a street driven car.

You normally do need (or more like "can get away with") a larger TB (or carb) to make up the lack of plenum volume available to each cylinder.

Single planes are set up for upper RPM HP. The runners are short and straight, and offer a larger plenum available to each cylinder (which you've pointed out). This enhances upper RPM HP, because as a lot of us know, the more RPM an engine spins, the more cfm each cylinder requires in order to put out more power. That's why the plenum is not divided.

The trade off is each runner is shorter and different lengths, so torque below peak is lower because the VE is lower (as you've also said). Because they're shorter, the pulse wave of each cylinder is 'tuned' to a higher RPM. Very bad for VE, as well as MPG.

I think we agree on that.

The consequence is you need to use a cam that has a ton of duration, goobs of lift, and a close LSA (more overlap) to take advantage of the upper RPM HP that single planes offer. Being the 'great tuner' you are, you should know that the ECM does not like the shorter LSA (more overlap) at idle because it does not provide enough vacuum to keep the MAP sensor 'happy'.

When using TBI the LSA needs to be wider to keep idle vacuum high, the upper RPM HP drops, which totally defeats the purpose of using a single plane intake in the first place. Why is that hard to understand?

Everything needs to be matched together to provide good results. Putting an LT1 cam (just an example) on stock heads (or slightly better than stock) with a single plane intake is not going to provide good power in the lower OR upper RPM ranges. They're "mixed parts", as it's called.

I've said, you can provide a 'band aid' for a single plane by using a smaller bore TB to build velocity at low/mid RPMs, but that's all it is . . . trying to make up for something that shouldn't be used in the first place.

The Holley TB that you use only flows less than 500 cfm @ 1.5"Hg (to compare it to a 4V carb). That's not enough CFM to justify the use of a single plane. I'm sure the plenum volume of a single plane is sufficient for an immediate burst of power off idle, but once the air that's 'lingering' there is gone, that TB is not enough to compensate for the loss in velocity, nor provide HP above 5500 RPM.

Until someone gets a cam that has more than 230* @.050", and use heads with 220 cc intake runners, there's no need for a single plane. "Plane" and simple.

When I say "tuning" I'm not talking about sitting in a chair punching numbers on a computer. I'm talking about tuning the engine for drivability and practical purposes.

Believe what you want, but single plane intakes have a very narrow RPM range they're good for. Sure they provide higher HP numbers, that's what they're made to do, but that's not everyone's intentions. You're so focused on trying to prove everyone wrong (Carb VS. TBI) that you concentrate on HP numbers and 1/4 mile ETs. That's not practical for most people.

What I hope you do is either figure a way (inexpensively) to use 2 stock TBs, or buy a 4 bore TB and run four injectors. I commend your persistence on giving TBI a better name , but IMO, you're treading water. Thinking the way you are here, I can see why.

BTW, don't anyone take this as I'm against TBI. I'm not. If I was, my car would have a carb on it right now. When I can afford to buy the Holley Commander 900 CFM, then I'll brag about it. I can assure you. I'm just against trying to make high RPM HP with a 2" bore, 2 bore TB by using a single plane intake.

 

yeah, yeah, yeah.....
you are ignoring what Pablo and many others have said who have used a single plane intake with TBI. that is, it doesnt lose low end torque. this is coming from people who have done it, have you? i know i havent, i run a 750 edlebrock in the winter and a 600 holley with no choke tower in the summer on a stealth intake (its a dual plane). i have no intentions to go to a single plane intake..............

 

And to show what kind of person AJ_92RS is, here is a PM I just received from him:

>>Make another personal comment about me and see what happens <img src="images/smilies/added/nod.gif" border="0" alt="">.

There you go folks. . . Shows what kind of person he really is.

RBob.

 

Pablo switched to carb. Why would I use him as a basis for 'what others have done'?

Show me dyno numbers that prove this and I'll believe it.

And 1/4 mile times are not a dyno.

Actually I'll accept 1/4 times IF and only IF that was the only modification or switch made. From an aftermarket dual plane to an aftermarket single plane that are of comparable design.

Oh wait..... when you guys say 'single plane', you're not talking about a REAL single plane? I suppose you're talking about the open plenum 'dual plane' design which (as I said earlier) is a sad attempt to combine the advantages of both.

Maybe that would work "OK". But still, I wouldn't be one to gamble on it. I'll stick with what I know works.

 

You showing that shows what kinda of person you are. Not able to hold a 'non name calling debate', so you resort to those kind of actions.

That's mature.

BTW, moderators have been informed. And you have another PM.

Just so you know....... PMs are just that. You posting mine is just immature. VERY immature.

 

Not everything is as black & white as you'd like it to be. Too many variables in life. I keep an open mind and listen to what everyone has to say. I then filter that information and make a choice based on that input vs. the requirements. Different circumstances call for different solutions.

This list isn't about who can argue the best, it is about giving & receiving decent information. Relax a bit and we will all benefit.

RBob.

 

(double post)

 

Well I don't have anything to say about the thread itself. There seems to be two opinions being discussed, and without hard proof, both are just that. Different avenues.

Although I have to say everything was going OK until you stepped in with the above comment.

If you believe this then follow it. Making comments about someone beyond what you know about them is as idiotic as saying chocolate ice cream tastes bad even though you've never tried it.

Everyone seems to be trying to help the original poster, just giving the info they've used and believe. Calling someone a cinder block is far from keeping "an open mind".

 

I think AJ_92RS, you are a little too focused on runner length and resonance tunning. When runner cross section and "location" are probably more important. A single plane manifold with small runners create velocity too.

Maybe not the best example, but look at the LT1. It has 3" runners a huge plenum, a little cam, yet they make lots of torque down low stock (~300+ rwtq from 2500 rpm to 4500 rpm). You're saying the LT1 is a poor mismatched combo right? How much more torque does a L98 have over a LT1 maybe 10-20 ft-lbs, but how much HP does the LT1 have over the L98, ~50 hp.

You guys can tear me up if you think I got it all wrong.

 

Jeez, this was almost a waste of everyone's time.
AJ, since I'm in a good mood I'll just say that I disagree with too much of what you say to even reply. You're last post about hp and torque and mixing cam selection blah blah and then narrow rpm range powerband is just all so off base I can't think straight. I'd need either money or some SERIOUS freetime to reply to everything. I guess I have a big problem with how you compare apples to oranges to coconuts to carrots. If any of you want to continue this topic either PM me or start a new thread.