Single plane vs dual plane intake using performance throttle body EFI

[folkenheath]

So I decided to start a new thread since a discussion has surfaced in @Chevy305 's EZ-EFI upgrade thread here starting at post #15...

https://ck5.com/forums/threads/ez-efi-1-0-upgrades.333912/

Rather than simply guestimating and being a spectator, I decided to dig into it a little more so we can learn things. I was going to suggest Glenn check his plugs and see what they look like since he is considering swapping intakes. Then I thought, I haven't changed my plugs in probably 9 years (seems crazy how time flies but the engine only has about 6k miles on it). So why not change my plugs and inspect. When I built the engine I just installed the plugs it recommended for those cylinder heads. NGK BKR5E. However, when building my 632 pump gas BBC (11:1 compression) for the regal more recently I called NGK and from the info I got for that I realized 5 was a little hot for this. So I am switching to BKR6E as well.

Some history, my engine runs good overall, pulls good, runs strong, gets 11 MPG on the freeway even with the stall converter slipping 400 RPM and usually tears it up at the sand drags in silver lake. The only spot I ever had a noticeable issue is just above idle with very low throttle (~5% or so) and low load where there is a slight hesitation. Its not there with more throttle, so overall, the self learning does pretty good. I built this engine for a carb in 2009. GMPP Bowtie Oval port heads, 10.2:1 compression, 231/[email protected] Lunati hydraulic cam with .600 lift, Edelbrock RPM Air-Gap Intake. A pretty mild dual purpose street/truck engine for my standards. Switched to FAST EZ-EFI 2010 and I still like it, nothing compared to the Holley Dominator ECU but it works good for what it is.

Lately I have been driving it about 10 miles each way once a week for a mountain bike ride. Pretty easy driving, low RPM (under 3k) stuff, so the plugs should be a good estimate of the lower RPM range (which is more in question). Now I have had mine set a little rich at idle and cruise (12.5:1 A/F) because it seems to lessen the hesitation just above idle at very low throttle, so I figured it would be richer than it needed to be, as I have it running leaner at WOT (12.9:1 A/F) but haven't run it at WOT in quite a while. My plugs are shown in the picture.

Other than the high temp copper colored antiseize still on the threads, I can definitely see a pattern. First they are all rich as I expected at low RPM operation, maybe more richer than I expected. Furthermore, there definitely is a difference between the upper and lower planes of my dual plane intake. The upper plane plugs on my intake are marked with a sharpie...2,3,5, and 8. They are definitely richer. The lower plane plugs are whats left...1,4,6, and 7, those are closer to optimal but still rich I would say. My Air-Gap intake does have the large opening in the divider between the upper and lower planes, however, there still seems to be a difference.

So after seeing this information on my engine and knowing I have an auto trans with a 10" converter for playing in the sand mostly, I decided to order a Dart single plane oval port 4150 style intake to try out. I never thought I would have a single plane oval port intake as to me I would normally go rectangular port with single plane along with a solid roller, but its on the way. I figure I can sell my RPM air gap for a decent penny to help cover the costs.

More info to come as I complete more testing. Testing has shown there is a rather large A/F ratio window to hit while still getting near max performance. So the question is will the slightly longer runners of the dual plane intake do better or is the better distribution of the single plane intake going to work better with this performance throttle body EFI setup?

I hope to get some real numbers to find out...

 

[AJs72K5]

This'll be interesting to see. I was already planning on going single plane when mine goes back together. But, you'll prolly get there well before I do Heath at the rate my stuff progresses.

 

[Chevy305]

Oh wow big difference in plugs between the different planes. I'm really curious about how the single plane will turn out. I can't wait to get my single plane intake installed. Just gotta find the time.

That reminds me, i haven't checked my plugs since I installed my Dart heads.
I need to pull them and check them.

Also how does plug temp effect their reading? Also what is plug temp? I've always just ordered plugs listed my application and never given it anymore thought.

 

[K85 Octane]

It was either Roadkill or Engine Masters that mentioned the idea that EFI might like single plane over dual plane. Had something to do with carb vacuum through the venturies not caring about the intake VS the injectors spraying down on a split level intake. It came up when they noticed a difference in plug/ cylinder health.

 

[folkenheath]

Also how does plug temp effect their reading? Also what is plug temp? I've always just ordered plugs listed my application and never given it anymore thought.

The plug temp is how hot the plug tip gets during operation. A colder plug can transfer more heat away and a hotter plug leaves the tip hotter by allowing more area to contact the combustion chamber. Too cold of plug will foul out. Too hot of plug can cause detonation/pinging. Generally the higher compression and higher power need a colder plug. So as you go up in compression or power you need to drop to a colder plug to hold off detonation.

Here is some info from NGK...

https://www.ngk.com/learning-center/article/207/i-have-slightly-modified-my-motor---do-i-need

This image comes from that page...

This is a chart to convert different manufacturers. I almost always use NGK plugs, they have a nice plating on the threads that helps prevent galling, and they have excellent customer service and good quality. I have used Autolite, Champion, Delco, and NGK previously. From speaking with NGK as a starting point they use compression ratio as the most important.

This website has some info about reading plugs...but there is all sorts of conflicting info out there so be careful. If you are trying to tune your WOT A/F ratio then you can't let the engine idle before you read plugs, which is difficult.

http://members.uia.net/pkelley2/sparkplugreading.html

Cross reference chart from NGK..

It was either Roadkill or Engine Masters that mentioned the idea that EFI might like single plane over dual plane. Had something to do with carb vacuum through the venturies not caring about the intake VS the injectors spraying down on a split level intake. It came up when they noticed a difference in plug/ cylinder health.

Yes the theory is that a carb uses the different planes and runner lengths to give the venturis better signal at both low and high engine RPMs. Speed density EFI mainly reads the signal from the RPM along with manifold pressure and temperature. It calculates the airflow from that (among several other compensation factors like throttle position, throttle movement, coolant temp, etc). Anyway, it injects the fuel based on that, and unless you are running sequential MPFI, it cannot compensate for individual cylinders. So a TBI motor just injects the same amount of fuel and the intake delivers it to the cylinder head ports.

Now, irregardless of carb venturi signal, a typical dual plane intake still should have slightly longer runners on average than a typical single plane because of the overlapping runners, which should theoretically give you more torque down low, and a single plane has high flow short runners which is better for top end HP. However, if the fuel distribution is not equal with the EFI, the engine might make less power across the entire RPM range. That is what we are trying to investigate here.

 

[folkenheath]

This'll be interesting to see. I was already planning on going single plane when mine goes back together. But, you'll prolly get there well before I do Heath at the rate my stuff progresses.

Yes after looking at single plane intakes for an Oval port BBC with a 4150 flange I didn't like my options much, most of the really good ones seemed to be for a rectangular port and/or a 4500 flange, until I found the Dart one. That looks like a good flowing performance intake, exactly what you would expect from Dart.

 

[sweetk30]

if you think about it . . . .

almost all efi is basicly single plane . . . just we would be adding fuel in the mix unlike stock adding it in the port runners .

so i am also in for the results on this one .

 

[Chevy305]

http://www.hotrod.com/articles/19-single-plane-small-block-chevy-intakes-test/

Based on this comparison test I bought the Holley Strip Dominator. Seems to be the best all around intake for the best bang for your buck. Unfortunately most single plane intakes don't have provisions for the factory alternator bracket. I had to buy an aftermarket turnbuckle style to go with the intake.

 

[folkenheath]

http://www.hotrod.com/articles/19-single-plane-small-block-chevy-intakes-test/

Based on this comparison test I bought the Holley Strip Dominator. Seems to be the best all around intake for the best bang for your buck. Unfortunately most single plane intakes don't have provisions for the factory alternator bracket. I had to buy an aftermarket turnbuckle style to go with the intake.

Wow, I figured the Super Victor II would be toward the top for peak HP, but I did not expect it to be 1.3 ft-lbs from being the best in average torque as well, beaten only by the Titon. If you examine one of those in person (at least for the BBC) it makes the original Super Victor look more like a Torker, ha ha. I figured the huge plenum volume would drop the low end more, but I guess they were only measuring from 3500 up, and they used a 406, which is not a typical small block. That intake is probably huge compared to most of the others in the test, its 1.25" taller than even the Dart.

The new Weiand Track Warrior intakes look like very good finish quality with the permanent mold castings (Like the modern Edelbrocks such as the Super Victor II). However, the such low price makes me wonder where its made?

The Dart looks like it did toward the top in most of those performance tests, they typically build very efficient components. Also they use a stronger more durable 355 aerospace aluminum vs the 356 most everyone else uses.

Of course my BBC test is a completely different animal so we'll see what happens. AJ is swapping his BBC to single plane too but he is also changing a few other things at the same time so the results will be different. Your results for the SBC would be good too Glenn.

 

[Smokinthehippies]

I’d be curious to see the results on a more “standard” engine. All of your engines have enough work done to them where I could see them making a single plane work.
Im wondering if a basic “350 with a cam” type engine that would normally see an air gap or performer, would be better or worse going to single plane with the tb efi.

Does the efi offset or make up for the engine being “over-intaked” for its intended usage? Most single planes advertise 3500-8000 range. But after seeing the plug difference it doesn’t look like the dual plane is doing the engine “right” either.

 

[beags86]

Sub'ed

 

[folkenheath]

I plan to swap the intake this week but I have to port match it just like a did the dual plane in 2009. Where does the time go.

I took it to chassis dyno (I've used real engine dynoes before but never a chassis dyno) for a baseline last week. The ole super swampers didn't like going 120 MPH so we had to shut it down early. Was shaking the truck at that speed and the curves were not smooth. I switched to low range 2WD for a couple other pulls just to get some numbers up to redline at 5800.

I consider my engine pretty mild but its all relative. It peaked at 5200 RPM like I expected and that would normally be better with a dual plane under a carb. So we'll see how the single plane does but the converter limits what I can measure at lower RPM and I'm not pulling the engine and spending mucho bucks on a real dyno. These pulls cost me $86 and I expect a little more when I go back because I want to swap tires at the end.

I will say with the super swampers it didn't put down what I expected knowing it will smoke my Dad's trailblazer that runs 13 flat in the quarter. Which means its a solid 12 second 5500 lb truck with me in. I think something is going on with the big tires and converter interacting with the chassis dyno. I may try some stock type tires next time but I will still get a number with the swampers because we need a comparison curve not a peak number. Peak numbers to the wheels were only 322 hp at 5200 and 336 lb-ft @ 4600. I will share the whole graph later when we have final numbers to compare too.

If I put all the drivetrain and engine data into the computer software it estimates 525 hp and 600 lb-ft at the crank and will run 12.80s at 101 MPH in a 5500 lb truck with me driving, which actually seems pretty close to reality knowing what I know. Which means there is almost 40% missing(not the 10 - 20% you read about), but that same 40% isn't missing when I actually race it, it puts the power to the ground. So its very strange.

Maybe I should of taken it to the track and gotten a 1/8 mile times (too fast for the tires on blacktop in the quarter). It would likely give me more realistic results that the chassis dyno. But I was trying to measure low RPM power. I even did a 15% and 40% throttle pull for comparison but we really didn't get any data below 3000 RPM. I did measure my engine vacuum and all that stuff at idle so we can compare that to the after if there is any change.

I think I need new tires, these tires are from 2003 and they aren't made for that stuff. But they work fine offroad and sand drags and tooling around running errands and going mountain biking and stuff. ha ha

 

[beags86]

Surprised they let you run with 36s. I had to twist the guys arm to let me run a set of 33s once. I suppose money is money.
You probably lost alitte hp/tq to some sidewall twist and defection.
I'm interested in to see what it makes with some Dyno rollers.

 

[Chevy305]

tooling around running errands and going mountain biking and stuff. ha ha

Sounds like a job for a Subaru...


I'm really looking forward to seeing the Dyno comparisons. Life has been getting in the way of me swapping my intake as well. But good idea, I will definitely write down all the stats in the ecm to see how they compare.

 

[AJs72K5]

I sent Jegs a bundle of cash for my single plane on Sunday night.

I've got a set of Procomp Extreme ATs. They're not Swampers by any means, but they're 10 years old at this point. The thought of them throwing chunks of rubber on the dyno crossed my mind more than once.

 

[folkenheath]

So I yanked the old intake and bolted the single plane on with a set of "blank" gaskets to let it sit overnight that way. It's a trick I use to get an exact indentation of the cylinder head ports on the intake manifold. I simply spend 10 - $20 on a set of blank gaskets, put silicone around the ports on only the intake side, and then bolt it down. The next day you pull it off and the gaskets are stuck to the intake with an exact indentation of the head ports with proper alignment on both sides using the same thickness gasket you will run during actual install. You just be careful to center the bolt holes front to back before you bolt it down and do the same on final install. Once you pop it off I like to take a sharp silver sharpie or pencil or something and make a manual outline right where the head ports indented. Just make sure you pay attention to what side of the line you need to port to. That way if the gasket decompresses before you are finished porting you can still see the line. It costs a little money but the amount of time it saves trying to measure it all scribe it, and the accuracy it produces even over that or just a simple gasket port match is worth it in my opinion. Spend less than $20, save time and get better results too.

I’d be curious to see the results on a more “standard” engine. All of your engines have enough work done to them where I could see them making a single plane work.
Im wondering if a basic “350 with a cam” type engine that would normally see an air gap or performer, would be better or worse going to single plane with the tb efi.

Does the efi offset or make up for the engine being “over-intaked” for its intended usage? Most single planes advertise 3500-8000 range. But after seeing the plug difference it doesn’t look like the dual plane is doing the engine “right” either.

I don't think there is an engine that works best with a performer. The RPM version (air gap or not) almost always makes more power than the regular performer, and I mean throughout the entire RPM range, not just the mid to top. I say almost because although I have never seen one, its not impossible for it to exist.

Also, I think this Dart intake is normally "overintaked" for a 5200 RPM HP peak oval port big block. I would normally not put one on this engine with this cam. I would typically stick with oval port heads and a dual plane intake with most hydraulic cams. However, this EFI is not creating even fuel distribution to the cylinders even at lower RPM. So mainly because of that data from my plugs, I figured the EFI would be better off with the single plane. We'll find out soon I hope.

 

[Chevy305]

 

[Bent77]

I’ve secretly been lurking on this. Curious about the dyno pulls

 

[folkenheath]

Well I got the intake swapped last week. I port matched it a lot, had to match what I did with the Edelbrock back when I built it. This Dart intake had a lot more material to work with which took more time, I had to make sure to port it back in far enough to keep the runner taper correct and not create a restriction before the head. I also had to get a new upper radiator hose and water neck because the new thermostat mount was lower on this intake but it turned out to fit better once I got a better angle on the water neck. That water neck would of hit the engine cross bar before. I did end up having to mill the intake because it was sitting so high the intake ports and water jackets were barely touching the gasket at the bottom. Once it was milled it fit perfect.

Anyway, back when I first started it with the dual plane it died when I put it in gear with a fresh base tune. Then it learned and I tuned it over time to get better. Well, I started over with a fresh base tune since it was obviously not running optimally in the lower RPM range with the previously learned tune. And it fired up immediately and I immediately put it in gear to back it out a little so I could set the timing and it ran perfectly from the beginning, I set the timing at exactly what it was before. It now makes slightly more vacuum at 800 RPM (~15 inHg) than it did before at 850 RPM (13~13 inHg). Also, before I had to richen the mixture to reduce the hesitation at very low throttle just above idle. Now even with the stock base settings the hesitation is gone. I can barely press the throttle and it will just idle away.

For some other idle parameters. I did not touch the butterflies and the timing is the same, so the warm idle parameters can be compared. Previously it idled best around 850 RPM, was using 9 lb/hr of fuel(would wander between 8-10), had 12~13 inHg of idle vacuum, the IAC was hovering around 27.

With the new setup it idles at 800 RPM while using 6 lb/hr of fuel. It has 15 inHg of vacuum, and the IAC is only open to 5. If you change the RPM to 850 to match the previous RPM, vacuum is about the same and the IAC opens to about 15. So it is using less air and fuel to idle at even the same RPM, and I haven't even played with the A/F like I did before to try and optimize it yet.

HP so far feels similar. I beat on it all weekend and at the dunes and I can't feel a difference. We'll see later on if I can measure one or not. However, I can tell an obvious difference at low throttle low RPM low load. Overall so far I think it is running better and it was worth the swap. I'm not sure if it makes any more power or not but it does run smoother down low with this intake manifold. I'll keep you posted when I get it back to the chassis dyno but it might be a month or more.

 

[AJs72K5]

Sounds promising. Curious what the long term looks like. I pulled up an old vid from when I first fired my 496 and at idle it was using 10lb/hr.