EFI Boxer

Status update.

Tuning
Road tuning has worked pretty well. I'd still like to tune on a dyno, but I'm confident driving around town. At this point, I feel the dyno would be a matter of optimization, not absolute necessity (which I believe echoes some previous comments). The car appears to be running really well. I'm now tweaking / refining things like cold-start and warm-up routines; which require the car to be completely cooled off. I basically only get once a day to try it. Granted, it never gets freezing here in Miami, so I can't test that, but even without an IACV, the car starts up and idles almost like a new car.

Tach
Got this working. I needed a pull-up resistor on the signal to the tach (which my Motec dealer pointed out). I am reusing the connector to the Dinoplex, where the new connector only has the ECU tach signal (TE Connectivity / AMP 180906). Since the existing connector already has a 12v IGN SW supply, I simply jumped pin 6 (12v) to pin 5 (tach) with a 1.5k resistor and the tach signal from the ECU. Quick calibration, and I have a working tach.

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Intake Air Temp
I experimented with ducting that went straight back to where the old air boxes were. This was very crude, as I didn't create new boxes that protected the cooler / cleaner air being fed in. Still, temps were 5 deg cooler than when pulling air from the lower corners. So basically, I'm looking at 15-20 C above ambient with crude ducting straight back. 20-25 C above ambient going to the lower corners. 35 C above ambient with no ducting at all. Maybe I shouldn't have been so skeptical of the wing after all. I am going to try a few more air locations before finalizing the intake path – including pulling air off the roof a la Competizione / Koenig.

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Misc.
I wasn't able to do much else as I lost a day replacing a CV boot. Funny the juxtaposition going from keyboard clicks back to a messy job like CV boots. Really though, all that's left is finalizing the intake path, and a dyno day to test my results. The rest is minor (eg, I should probably do something about the crankcase breather, and some other odds and ends). Afterwards, I'll tally the costs, and call this phase done. Hopefully this thread will give enough of a blueprint (good and bad) to others who might want to do an EFI conversion.

 

Something like this? I was thinking of something similar, trying to avoid a scenario where opening the engine lid just unveils a bunch of intake boxes covering up the trumpets. The sealing box would be attached to the lid (not the intakes). I also figure, even if I don't go full scoop, I can at least do something similar to the 365 with the cutouts on the sides.

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It does seem these are the two options:

1. Vertical ITBs and figure out where to get cool air. Probably skip the windows.
2. Modify the stock plenums with more volume and larger throttle bodies.

I think an argument can be made for both, but I think I just have an irrational desire for ITBs at this point. I've always liked the look and sound of them. They even make the Honda K20 sound good.

 

I've all-but made up my mind to go with Jenvey ITB, and orientated vertically (a la the LM cars). Even if the plenums could be modified to work well, I think the look and sound of ITBs is just hard to beat, plus the homage to the BBLM; which the upgraded engine internals would also be reminiscent of (hopefully a similar exhaust lope as well).

I'll figure out something for the intakes covers, and I can pretty easily experiment with trumpet heights. It's not exactly twisting my arm to do a Koenig-style roof scoop, but there are probably a few ways that can go. None of this seems like deal-breakers or blockers to really getting started. Thankfully, the engine management work I did (ECU, harness, injectors, coils) should all carry over.

I have had a few exchanges with the folks at Jenvey about what parts they'd recommend. So far, nothing beyond what's already been discussed here, and we're finalizing a formal quote.

After all, why should Singer have all the fun with ITBs on a flat engine?! Just imagine this, but... twice as cool.

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Status update.

Intakes
I experimented with removing the lids over the plenums, and routing the intake ducting to the air above the engine lid. This resulted in 25C above ambient temps. That is 10C lower than pulling in hot engine bay air, but 10C hotter than pulling from the stock location (rear, above exhaust). So far, Ferrari's original design is proving best. I will try pulling the air from the roof as one more experiment. Attached is a photo (don't judge too harsh, it's only temporary).

It seems the empirical evidence is supporting most people's assumption: either pull from the stock location, or roof scoops. Everything else is sub-optimal.

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Phase 1 (EFI) Costs
I've pulled together most of the costs to convert from CIS and mechanical ignition to EFI. I'm still tallying some of the wiring and heat shrink costs, but the bulk is accounted for. At the moment, it's looking like $18k in materials. This does not include the costs for R&D; which I estimate is another $3k. For instance, I changed injectors, went through multiple iterations on brackets, etc.. This also doesn't include the costs of specialized tools (eg, 3D printer). This does include a $3k expense for the PDM; which really was unnecessary (but I don't regret). Obviously, this does not include the cost of labor; which was substantial (mostly the wiring harness). When I'm finished with the tally, I will make the spreadsheet available so everyone can see what is and isn't applicable to them.

It's worth pointing out (before someone else does), this can be done cheaper. I tried to use the best components I could though (practically speaking), and that comes at a price.

Phase 2 (ITB)
I am moving forward with ITBs. I need to really dig into the manifold design, but the plan is to mimic the stubby manifolds from the LM cars. I purchased the throttle bodies, fuel rails, and levers late last week, so it'll be a few weeks before they arrive. I went with 42 mm Jenvey ST throttle bodies. Jenvey is making custom fuel rails to replace the ones I created. I probably could have reused mine, but their rails mount nicely to their throttle bodies, so I went with that. The plan is to reuse the stock throttle lever and tweak the tie-rods. The "primary" throttle linkages are placed between cylinders 2/3 and 10/11 (similar to the stock locations). I thought about doing something similar to the BB throttle linkage, but we'll see if I can make the BBi setup work.

I also need to figure out the air box / filtration piece of this. The BB route would be more discreet, but limit trumpet height. The Koenig route would be flashy, and allow for taller trumpets. FYI, there is about 10" / 255 mm from the cylinder head and the top of the engine lid flange (pic attached). With my currently designed manifolds and Jenvey throttle bodies, a 150 mm trumpet would put the tops right about 10". If I want to go taller, I need to find taller trumpets, have them custom made, add a spacer between the TB and the trumpet, or increase the height of the manifolds.

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Side note, the 4.0L Singer engine pic I posted the other day is made by a collaboration between Ed Pink and Kinsler. Those are Kinsler throttle bodies. I believe Kinsler also makes a custom trumpet with screw-on filters. I think they look really sharp (not sure about the HP drop). I am going to reach out to them to see if I can get more info. Ed Pink and Kinsler both sell a Porsche direct-to-head intake kit that is identical to the one used on the Singer (they don't use the Singer name in their marketing). Could be a dead-end, but I figure it can't hurt to reach out (all part of the R&D process).

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Misc
I think it's just about fair to say that Phase 1 is complete. I am going to put most of my effort towards the manifold design while I wait for the Jenvey parts. Probably going to be an uneventful few weeks while I wait.

 

Thanks, Romano. It definitely is a lot of work, but I'm also happy with how things are turning out. These are great cars, so I feel they deserve the effort.

I wish I was retired! No, I just have a very understanding wife and a job with a flexible work schedule. I am a software engineer by trade, and I am the CTO of a real estate software company I co-founded. In 2022, I sold another company I also co-founded; which is how I am able to fund such an expensive hobby. I'll take a little break when I send the car to Paul so he can work his magic (at least that's what I am telling my wife).

 

Tough question, and I imagine that somewhat depends on the person's preference for filtering vs breathing. Considering the reputations of Singer, Ed Pink, and Kinsler, I'd like to assume they did their homework in finding the right balance. But yeah, I am curious myself. I'm also interested in the heat issue. As I am experimenting with the plenum intake, it's pretty apparent that I wouldn't want the trumpets ingesting the hot engine bay air. It's only recently that Singer started pulling air from elsewhere.

Also, Kinsler got back to me. They are swamped right now, and aren't taking on any new projects. They declined to provide any detailed information on the trumpets and the filters, so it's a bit of a mystery. Attached is another picture of the trumpet with the filter off. It seems like a straight-forward (but clever) design that I could replicate if I really wanted to.

Another option is PJ Motorsports. Not quite the same aesthetic though.

If I go with a roof scoop or under-lid airbox a la BB, then the trumpets may be sealed in an airbox that itself is filtered (negating the need for per-trumpet filters). Personally, I think it would be really cool to see the trumpets from outside the car – especially if they stick up above the engine lid (a la Can-Am). I'll figure something out, but I'm still just spit-balling / exploring different options.

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Status update.

I should be receiving my Jenvey parts (throttle bodies, 90mm trumpets, sensors, and IACV) in about two weeks. In the meantime, I've been working on the manifold design. The assumption right now is that I'd have them CNC'd, but I may be able to test a short-term solution using laser cut flanges and 3D printed runners. The tricky part (in both cases) is accommodating the coolant.

At this point, it's fair to say this "modificata" exercise is very much inspired by the LM cars. This makes sense for a few reasons, not least of which is that the LM cars actually had ITBs. I've been doing a lot of research; which is helping both with inspiration, as well as creating structure / rules for myself. Particularly around the manifold design; which appears to have been tweaked between the Series 2 and Series 3 cars. 35527 underwent a restoration in 2017; where they took a few photos (some of the best shots I've been able to find, albeit low-res). One change is that the manifolds are not connected at the base (as they are in both BB, BBi, and Series 2 manifolds). Rather, they are connected at the top flange. Probably a meaningless difference, but it's now part of my design. I reached out to Dugan Enterprises (who did the restoration) requesting any info / pictures they'd be willing to provide. In the meantime, I am mostly winging it. Note, in my design, the bolt holes for the throttle bodies are on the same side as those on the manifolds. This will face the injectors inward.

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I also received my first parts for this phase; which were 150mm trumpets that bolt to the Jenvey throttle bodies. I 3D printed dummy manifolds and throttle bodies with correct heights to get a sense of proportion (I had some red ASA I wanted to use up).

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I also 3D printed a dummy flange with the correct cylinder spacing to see how close the trumpets get to each other.

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The total height in the engine bay photo is about correct (~260mm). As you can see, the trumpets are almost touching. A little different than the BBLM trumpets which do not flare outward as much. For now, I am going to use these as the primary trumpets, but I may decide to fabricate something custom that has the exact height I want, the exact top diameter, and maybe even incorporate the threaded bellmouth like the Kinsler. I think the most important thing is getting the manifolds right. The trumpets are something I can experiment with.

I'm still just poking at intake path and filter ideas. Nothing concrete yet. I started designing a roof scoop a la Koenig, but with side windows, and angled towards the outsides since the trumpets are not centered like they would be on the BB lid. Not sure how I feel about it.

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A simpler solution is to use shorter trumpets to keep them under the engine lid, and an air box with an inline / integrated air filter that pulls air from the rear (like the BB).

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I have other ideas as well. My preference is longer trumpets that aren't all covered up by filters / air boxes. I'll keep poking at it. All designs are based around the idea of vertical trumpets though.

 

I haven't tried pulling from the roof yet, but so far, Ferrari's original design of directing air to the rear louvers via the wing is proving to provide the coolest air.

To your point though, with stock compression, I think I can be a bit more lax with air temps. With higher compression, I think it'll be more important to get as cool air as I can to limit detonation / knock running pump gas.

 

Same! I definitely will not remove the plenums before I've had a chance to dyno the car so it's clear the difference ITBs made.

 

Thank you. Trying to do these cars justice.

Yeah, the BBi's engine lid intake covers are not directly above the cylinder intake ports like they are on the BB. I'd prefer the trumpets to be centered, but I don't want to angle them to make that work – opting for a more BBLM appearance (vertical manifold / throttle body / trumpet). Still mulling over ideas on how to address this.

BBLM ITB (1-6):

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BBi ITB (1-6):

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Thank you. Like so much of this project, I think about it in my sleep, and often just stare at the car thinking of different ideas. I'm sure I'll come up with something that "feels right". Obviously, a custom engine lid would solve the problem, but that seems really extreme. I'm sure there's a more practical solution in there somewhere.