EFI Boxer

I believe I have the manifolds pretty close to final. I'll need to refine once the Jenvey throttle bodies arrive, and once I remove the stock manifolds. As mentioned above, these are heavily inspired by the BBLM manifolds.

I have the internal diameter at 42mm throughout, but I believe the head ports are only 35mm (at their widest). I was thinking of lofting the 42mm circle down to the exact shape of the head (including the cutouts for CIS injectors). Then, future engine work can port the heads and manifolds (up to 42mm).

I am operating under the assumption there are three manifold designs:

• cylinders 1-3 (coolant on 2).
• cylinders 4-6 & cylinders 7-9 (same manifold, just rotated)
• cylinders 10-12 (coolant on 12)

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I have "instant quotes" from Xometry to CNC the manifolds (aluminum), and Protolabs to DMLS (3D printed aluminum). CNC will cost about $4k for all four manifolds, and DMLS will cost about $9k for all four. DMLS seems unnecessary – I only mention it because I find it really fascinating.

I did a test print out of ASA for the 10-12 manifold. I won't do any test fits on the car until after I've had a chance to dyno it with the stock runners / plenum.

 

Status update.

Still waiting on the Jenvey parts. I've been doing a lot of research on the Competizione and BBLM cars. Unfortunately, Dugan hasn't respond to my emails, but I did pick up a good book "Ferrari Berlinetta Boxer, The Road and Race Legends" (no longer in print); which has over 100 pages on the LM cars. Not to be confused with the recent "Berlinetta Boxer, The Legend" book.

I'm working through two different intake approaches:

1. Competizione / Koenig styled scoops.
2. BB styled under-lid intakes with half-windows

I'm leaning slightly towards option 2. I'm not super in love with either option yet, but I've included some screenshots so you can see some of the ideas I've been trying. The intakes would be part of the engine lid, so when the lid is raised, you'd see the trumpets without obstruction. Working through a few options for the filters, but the idea is that cooler air pulls from the rear, and comes up on the side of the trumpets. I might be trying too hard to make the window work. I go back and forth between thinking it looks cheesy or looks awesome. Might need to see it in person to really know.

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I'm also working on a throw-away sheet metal fixture that will allow for testing the roof scoop. It's way overkill for just that purpose, but I am hoping it also gives me a rough sense on what a scoop would look like. The scoop inlet would be 3D printed, and mount to the ducting on the other side of the bracket.

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Hoping to get on a dyno in the next week or so. Otherwise, more CAD work and waiting for Jenvey.

 

Status update.

The Jenvey parts arrived! My guesstimates on dimensions based on their drawings were pretty much bang on, but the upper horizontal support borrowed from the BBLM design interferes with the primary throttle lever. A few ways to address this, but I figured nixing the top support was the easiest. I'm adding a new upper support that spans all 6 cylinders which should give a good amount of rigidity, and it's also borrowed from the LM design (although, the LM were per-cylinder, and used as essentially a clamp on the trumpet).

Also, I updated the manifold design to loft a 42mm top circle to the head inlet ellipse (~30mm x ~35mm). This creates a smooth transition that can be opened up via porting during the engine work phase.

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In the picture, you can see that the throttle position sensor is mounted on one end (replacing the string pot I am currently using). The fuel rail is the same length as the one I am currently using (570mm), and uses the same 6AN fittings. The fuel lines will wrap around to the current regulator location (the ones in the pic are too short and just for illustration – but it's the same style).

While I figure out a long-term solution for the intake path (eg, LM scoops), I purchased push-in filters. They're basically little K&N filters per cylinder. They likely interfere with air velocity, but I appreciate the minimalism.

Worth mentioning, I plan on stripping the blue anodization and polishing the trumpets.

Idle Control
Currently, I am only using timing; which dynamically advances / retards timing to maintain a target idle speed. This works well, and I'd be on the fence saying anything else is needed when using the plenums. However, I have heard ITBs can be a bit more tricky – particularly at idle. So I purchased an idle air control valve that will feed small amounts of air to the manifolds via vacuum ports. This is essentially a stepper motor controlled by the ECU. The idea works similar to the stock AAV, but when and how much air is let through is programmable (not on/off like the AAV). The combination of dynamic timing and idle air should hopefully result in quick cold starts and smooth idle.

Now that I have the IACV in hand, I can model it in CAD and design a vacuum bus. This will have a MAP port as well. Even though TPS will be the primary driver for tuning moving forward, MAP is still useful as a secondary.

Dyno
After many phone calls around Miami, I finally found one. Many stated "oh, it broke a few years ago and we never bothered to replace it". I have family in town this week, so I probably won't be able to have time to dyno the car for another week or so.

Schedule
After the dyno, I'll start the plenum tear-down and test fit the manifolds before having them made. I can already start modeling the IACV / vacuum bar, as well as prep the wiring. Also, I can switch from MAP to TPS (alpha-N) for the tune before switching to the ITBs. I think if all goes to plan, I should be up and running with ITBs by June 10th. Then I'll street tune, and dyno again.

 

I'm open to all ideas. I don't think I've seen that specific treatment before though (other than the Silhouette body, of course). Do you have any pictures / serial numbers?

 

Oh, I believe those are the Testarossa Koenig Specials, but I see what you mean. I don't think I've seen that treatment on a Boxer other than the Silhouette body. I haven't given a ton of thought to this because it seems like a pretty drastic change, but I have thought it would be kind of cool to create something custom that borrowed from the Silhouette rear. I rather like the rear grill of the Kimera 037; which I think would look really sharp with the "BB512" logo in the grill (usually painted white on the LM cars). I think it's even the same pattern as is used on the BBi rear valance (or very similar).

Anyway, that's a bit out there.

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I've heard similar. My understanding is that the MAP signal becomes a secondary layer of tuning ("background fuel compensation"). I'm not sure to what degree this compensation can't just be handled by closed loop compensation (lambda sensors), but I figure the sensor is already wired up, and I'll already have a vacuum balance bar for idle control (IACV), so it can't hurt. How did you handle idle? Did you use an IACV?

In a perfect world, the car would have modern road car startup and idle, but with performance somewhere between BB and BBLM (after engine work).

 

Interesting! Makes sense, now that you say it. You're referring to the throttle body though, not the manifolds, correct? Do you know if they just used BB manifolds since they were already designed to mate with the Webers?

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Yeah, I've come across a few pics that show this. For mine, the stacks bolt to the throttle bodies, but I also added a plate that spans the length of the bank to keep everything aligned up top. Thanks for the info. Explains a lot.

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Status update. Good news and bad news.

Bad news first. I went to have the car dyno'd. Maybe it had something to do with the VERY hot weather we've been having in Miami this past week, but the dyno was having issues (calibration?) and the owner didn't feel the numbers could be trusted. We think the dyno calibration was working at first, when I was warming up the car with a partial throttle run. It was meant to be a throw-away run so I could get comfortable with the dyno controls, but it came back with 260 HP and 300 FT/LB. We didn't even save the run because it just a quick test. Again, this was partial throttle (85%-ish), and I bailed at 5500 RPM. Even on that partial run, torque and horsepower were strong all the way up. There was definitely more to be had there.

If there's a silver lining, even though we ignored the actual dyno numbers, I did run the car hard to test my tune. The car ran fine, and the road tune only needed minor tweaks of the VE table at WOT. Everything else was spot on. This supports the idea that you can get a very decent road tune, given enough time to tinker. Unfortunately, this was really my only shot at dyno'ing the car after the EFI swap as I don't want to hold up the ITB install. After the ITB install, I'll try again. So basically, I would not get discouraged about the 260 HP number, but I wanted to be transparent that I did attempt to have the car dyno'd since I know many were interested to see what EFI alone would have accomplished. I feel confident the car has 300HP+ on what amounts to a "stock tune".

Okay, onto the good news. The very next day, I started ripping out the CIS intake. I did a test fitment of the ITBs, and they are very close. A few minor tweaks are needed to get a perfect fit (which was expected). One thing I did not consider is that the AC low pressure connection interferes with the fuel rail. A few options to solve this, but one quick experiment was to simply rotate the throttle bodies and have the fuel rails on the outside. I think this works well, and I think I actually prefer the aesthetics of the center area of the engine being clean. So, I guess that worked out fine. Also, it looks like I'll be able to use the existing wiring harness and fuel lines from the EFI phase.

It should take a few more iterations to get the manifold fitment perfect. Once finalized, I'll have them made; which will be about a two week turnaround. During that time, I'll finalize the vacuum block and IACV wiring. I'll also try to clean up the block a bit, replace the coolant hoses while it's drained, etc..

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I think I have a final design for the 10-12 manifold. After test fitting, I decided to bump the total height an extra 5mm (now 60mm total); which leaves just enough room for the throttle levers to rotate without touching the top of the coils. Also, with the manifolds off the car, I am able to 3D scan, allowing me to match the coolant port dimensions. I also added 1/8 NPT ports which will be used for vacuum and idle air from the vacuum block.

Hopefully, it's apparent that I am trying to create manifolds with an OEM feel. I basically cherry-picked aspects of the BB and BBi manifolds, and made tweaks to work with the Jenvey throttle bodies.

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Thanks. It's nice to see it move from the computer screen to the real world.

The dyno was an AWD Dynojet.