EFI Boxer

I might be able to get a stock intake flowed on a bench. I have two engines worth in pieces right now. I could bolt the plenum onto the runners and see what we get.

 

Just an idea for straight ITBs but lining up the trumpets with the BBI lid

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If you go with plenums again then I dont see the advantage in going with the ITB's anymore.

550's dont run ITB's and have two throttle bodies. You could use the stock intake, cut the neck off the bottom of the plenum and weld on a flange that accepts a larger throttle body. Assuming the manifold flows enough.

 

I was thinking more like an scurve as per the porche pic, that would then center the top of trumpets where they need to be on a BBI decklid. That's a far easier proposition than changing to and painting a BB decklid not to mention the fitting of different decklid on a hand built car. Koning intakes with window, S curved
trumpets to line up widow with BB decklid.

Interesting to see how the BBI intake manifolds slow as per Newman.

Besides cosmetics I understand ITBs can take some pretty wild cams. However Itb's and wild cams are a negative when it come to midrange tq. I guess the question is what would that Tq look like.

I wonder is anyone has 308 cam and ITB data to look at it might give us a clue as to what the TQ looked like vs stock.

Ill get some data pistons/.cams for the 512BB that had 470 hp.

 

To increase plenum volume on the stock intake you could machine a 1" spacer (for example) and sandwich it between the upper and lower half.

 

How are you directing outside air to the air filters and sealing them from engine heat?

 

Since you're drawing things all custom you can do just about anything you want. There's also something to be said for having the butterflies a bit higher, and even tapered to open more with even larger butterflies as that increases the total port volume and all the math that goes along with having more port volume. Porsche of course did this with their 2.8L and 3L RSR 'high butterfly' mechanical injection systems

 

I remember seeing some pics where the black covers on the hatch had holes drilled in them, not sure this helps.
Fresh air from somewhere is best, the roof intakes are not only great looking but have that period 513M and can am car for road vibe.
Putting an s curve in the trumpet would have the tops line up with the BBi lid.
Stock plenums may be best/easiest if they flow well enough.

one of the things I Remember from your Koning was the awesome intake sounds, I suppose some of that is just carbs, but a BBI is missing a big part of that symphony. Would ITBs sound similar tot he webers.

 

These are the specs from carobu on their 470 hp BB, efi should be able to do better than that, at least for tq. Does one need more than 450-470 hp, Imo not if it kills midrange Tq..


Model: 1981 Ferrari 512BB Boxer
Engine Specs:
399 lb-ft of torque @5100-rpm, 471-hp @7000-rpm

Click here to see details and dyno sheet on this motor.
Type: Flat-12, 512BB
Bore: 82mm Razzo Rosso forged pistons
Stroke: 78mm
Compression ratio: 10:1
Cylinder heads: intake ported and tested on flow bench, intake and exhaust manifolds matched
Camshafts: 246-degrees at .050", intake and exhaust, 9.1mm lift
Induction: Weber 40IF3C, 3-barrel carburetors, 32mm venturis
Exhaust: standard Ferrari headers, port matched and ceramic coated
Ignition: Stock Ferrari electronic ignition, new plug wires, BP7ES plugs

Suspension and Brakes:
Suspension: stock Konis revalved and converted to threaded-body coilovers, Eibach racing springs
Brakes: rebuilt with cross-drilled rotors

Wheels and Tires:
Wheels: 17x8-inch front and 17x10-inch rear Razzo Rosso wheels
Tires: 235/50-17 and 255/45-17 Pirelli P-Zero



The Engine Work
Before any modifications were finalized, the critical engine dimensions were measured and incorporated into an engine model for dyno simulation purposes. The most critical aspect of an engine, when it comes making power, is the efficiency and balance of the intake and exhaust port flows coupled with a complimentary camshaft design.

Cylinder Head and Camshafts

The first step in cylinder head modification is to establish the weak aspect of port flow. We test the heads on a Superflow SF600 flow bench that is computerized with a FlowCom attachment and fed into Performance Trends Flow Analyzer software. Most 2-valve Ferrari heads are intake flow deficient. In the case of the 512BB, the original intake port flows 160 cfm @ 28" and .350" of valve lift. At the same point, the exhaust port flows 125 cfm. Our calculations from our engine simulation software showed that an intake port with 180 cfm would improve power while keeping the torque curve needed for decent street performance.

The necessary porting work was done to the intake side and the intake manifolds were matched to the new port dimensions. We left the exhaust port stock, but used new sodium cooled exhaust valves from Zanzi in Italy. As a side-note, sodium cooled exhaust valves get a bad reputation in the Ferrari service business due to valve breakage. Sodium filled valves were made in the old days by welding the valve head onto the hollow stem. After 25-30 years of hot/cold cycles, the exhaust valves (this applies to 308, Daytona and Boxers) had a bad habit of breaking off the head which then embedded itself into the top of the piston; usually at high rpm. The result wasn't pretty. Modern designs use a one piece hollow stem valve so that the head doesn't fall off. As Ferrari designed the Boxer engine with sodium cooled exhaust valves for better cooling, we recommend putting new ones in during a rebuild and not using aftermarket stainless valves without sodium cooling. Granted, there is a price difference, but since we were planning on generating more heat in the engine (by making more power), it is a worth while cost.

Once the port flow numbers are finalized, they can be plugged into the engine simulation program. The camshaft profile can now be designed to take maximum advantage of the flow increase. The goal was good mid-range torque and top end power with street driveability. As it turned out, our 'Daytona' cam profiles tested well in the simulation. With 247º of duration @ .050" and a total lift of .363" (9.1mm) on both the intake and exhaust lobes, this would fulfill all of our goals. This profile would also allow the use of stock Ferrari valve springs (new ones were used). Later dyno tests would confirm the engine simulation work.

Engine Block

The standard 512BB bore/stroke dimensions are 82mm x 78mm yielding just under 5 liter of displacement. We didn't plan to make any big increases in engine size so the original cast iron liners were over-bored 0.5mm to give a fresh surface for the new Razzo Rosso forged pistons (10.2:1 C.R.). The original crankshaft was cleaned out, magnafluxed and balanced. The connecting rods were inspected, magnafluxed and rebuilt using new Razzo Rosso specification rod bolts and nuts. The basic 512BB bottom end is very strong so no additional modifications were needed.

Exhaust System

The standard Ferrari exhaust headers were retained and port matched to head. Ceramic coating was applied to keep the heat in and the rust out. To compliment the headers, a new polished stainless steel Tubi sport muffler system was installed. The light weight (over 40 lbs. less) Tubi bolted right on and sounds great!

Dyno Testing

After the engine build was finished, the dyno break-in and power testing/tuning begins. The engine started easily and ran the low speed break-in cycle without a hitch. Dual oxygen sensors were installed (one for each bank) so that the Weber carbs could be dialed in. As predicted, richer jetting was necessary to realize the maximum power numbers (see dyno test). The end result was almost 400 lb ft of torque with over 375 lb ft available from 4,000 to 6,500 rpm - perfect for strong street driving! Maximum power at 7,000 rpm was 470 HP. This is a 100+ HP gain over the standard engine. We achieved our goals and verified all of the engine simulation and design work.


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I would machine that entire growth off the bottom of the plenum and weld on a 4 bolt flange. The stock throttle plate bore is 56mm which seems small but that injected car I hot rodded with CIS friendly cams is a quick car.

Regarding the Carobu engine, Im surprised they ran 32 mm chokes. My 512 had 36's. The 3.4L V8 engines get 34's. That 512 is a pretty mild build with very unremarkable parts, the porting would be the key to those numbers.
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I love the look of the ITB's and knowing how my carb'd car worked with them (essentially ITBs), it did not lack bottom end torque and when you put your foot in it, it got up and went. So your car would respond similarly with supporting mods but run better, start better and get much better fuel economy. It would just be better all around.

I think there are two paths to take. Stick to the simple straight up ITB's with the tallest stacks that will fit copying the Koenig approach without windows. You could have a narrow base plate thats symmetrical around the throttles but keep it narrow to show off the engine as much as possible, then in the underside of the scoops you could have another sealing plate mounted with the oval slot cut off to one side with a seal on it. This way the visual of the stacks with the open lid is what you want and the offset upper plate on the lid obscures the misalignment with the scoops or makes it look intentional. Make sense? Cold air problem solved, looks great and it'll work great.

The other option is stick with the stock intake setup but mod it in a subtle way. Add volume to the plenum as discussed with two throttle bodies. The 400i and 412 uses the same throttle body / plenum piece as the BBi, it's just flipped upside down on the 400i. You'll notice the underside of your plenums say Ferrari on them where you cant see them, thats so the plenum when flipped over works on the 400i. Its not a rare part so hack up the used ones you buy. The car will make great power and more torque down low than the ITB setup but no slouch when you're winding it out.

 

hard to imagine these engines breathe through such small openings/throttle plates etc. It certainly seems simpler to mod the existing plenums. Also taking air from the stock vents sorta makes sense as that's supposed to be high pressure air coming off the roof.

The question that comes to mind is cam choice, would there be cam that would work with he stock plenums, and also be really good if one swapped to ITBs later.

Seems like a cis car with cams and pistons is a 400hp car. Is the difference to a 450+ hp car just loosing the cis, or does even the updated cis cam still present limitations to work with cis and there is more to gain on a different came if one is going with efi. Or put another way if one had efi would the cam be the same as the moded cis car, or something more agressive.

You're doing a cams and pistons car now, owner is a freind. I should be able to give an comparison report when he lets me drive it this summer, can compare to a stock car and also to your Koning which is still etched in the memory, as well as a subjective opinion as to whether this is already all the motor the car needs.

I guess next step up from that is efi stock intake for the easier conversion and stock look, then last stop are the ITBs, eye candy and immediate throttle response.

Interesting on the carobu car, basicaly cams and pistons plus some porting.

 

LM cars seem not to have too much done, maybe some compression, cams and that injection. Seems like if one removes the blockage of cis add cams and pistons its a 450+hp motor, maybe ITbs add another 30 hp, but one gains immediate throttle response. Either option is going to be a vast vast improvement over stock 340hp 9.0/1 compression and flat cams.

The Lm motor below seems to have made its extra power over the 470 hp car above by simply by being able to spin to higher revs 7700
.
https://www.carobu.com/bb-512lm-491-hp

 

Both are great solutions, the first one is choice in a budget free world. If porche guys can do these thigs and make their cars mroe desirable/valuable why cant we.
the all we need to figure out is workable Ac, lol.

 

The cams in the CIS car are still a big limiting factor of the engine's potential but a necessity as well or the car wont run right at idle. I've already pushed beyond what the accepted max is in the Porsche world when I first started toying with cam changes in CIS cars. I "got away with it" on the GTSi builds I've done as well so I know what I can use for cam specs without a big headache but they still dont compare to what I would run without CIS in the mix.

Using my 79 as an example, the heads and compression were untouched, I had the heads off so I could verify that. So with stock ports and compression, better cams and induction transformed the car. Will the induction be the cork in the system with cams and efi? Maybe but flow testing will tell. I'll see what I can do there and try to isolate if the throttle plate itself is the issue, an easily resolved issue.

The 4V 3.4 I built with EFI and a ported stock plenum and runners (with stock throttle body) produced 375HP on the dyno so the stock parts can be made to work. I wouldn't be quick to scrap them unless ITB's are what I needed to have so I could sleep at night.

 

Thank you, makes sense.
Would the cam with efi and stock plenum be the same as the one with ITBs for a street driven car. If so then its easy to do the whole thing in stages.

The two starting points are efi, and pistons/cams.

 

You could run cam choices on a sim program but you would need to know everything else about the parts you're using then fiddle with the cam only then swap the induction only and see whats best but.....If you want a streetable car then that dictates a few things in advance such as compression ratio, cam and fuel availability. I prefer pump gas so that becomes a limiting factor and means you have to keep it tame and other things might matter less because the fuel and the cams say this is how it's going to be. Pump fuel and street use being the goal dictates cam selection because you don't want it to ping from having your dynamic ratio too high and you don't want it to come in at 3500 and up. You can't have it all. You can't have the ideal cam for what the ITB's will support and the sim says is perfect then expect a streetable car in return with power that comes in at 2000rpm. You have to give something up. My cam choice would be based on a 10.5:1 compression ratio that that might fall off at close to 7K or under knowing that Im spinning it beyond that for the thrill only but it peaked somewhere back there - but I still had fun regardless of the induction. Swap the induction and you'll move your torque peak up or down depending on which you swap it to and leave the rest the same.

 

Thank you, this makes sense. Sp based on pump gas Cr ratio and street ability the cam is more or elss decided whether one runs stock plenums or Itvs. In that case if one started with the stock plenums machined to take a throttle body, and decided later to do ITBs, internally nothing needs change internally in the motor.

Itbs would move the TQ peak up the rev range and give snappier throttle response, add indication sound and visually be the bomb. One could possibly play with tq on ITBs by having narrow trumpets. I wonder in any how noticeably different the tq curve would be from plenum and runners to ITBs.

7K rom seems to be the reasonable limit for various reasons from mechanical empathy to gearing etc.

I guess one other question then, the 365 had a shorter final drive, how complex is it to achieve that on a BBi box. Slightly shorter gears would also wake the car up a lot. For modern highway ie below 100mph 5th is already tallish more of a cruiser than a performance gear