Road going ITB setup

[squirt46]

To summarize:  I'm trying to build a throttle body efi system for a 1973 BMW 2002, using the complete EM-5 system from Simple Digital Systems, which controls ignition and fuel) and gutted Weber DCOE carbs as throttle bodies.   My initial preference was to go port injection but there is not enough room to install the injectors on the underside of the induction system ( I was/am targeting a 'stealth' system such that it would appear to be a period appropriate hotrodded engine using Weber carbs.) .  All the hardware (manifold, linkage, air cleaner, weber bodies with injector bosses welded on, fuel manifold; fuel pump; adjustable fuel pressure regulator,  crankshaft timing magnets, etc. etc. has been bought and paid for.  

This has been on-going for some ten years (sporadically).  The engine starts, but I don't have suitable injectors (I'd erred on my original calculations when picking the pressure.  I now want 20 lb/hr at 13 psi; I don't know where I obtained the injectors currently installed but they appear to be  “https://www.atpower.com/products/magneti-marelli-pico-330cc-m-iwp043-fuel-injector” or equivalent.  I don't remember specifically what they are, or where I obtained them.  They appear to be bosch style connectors

Can anyone suggest where/how to search for injectors that will match my flow concerns and physically fit the injector bosses?

Thanks for the various suggestions.  I just dropped a note to RHD (was about to phone, and then realized that they were located on New Zealand's West Island), asking if their port injection manifold used the DCOE bolt pattern and would they sell me one along with the associated fuel rail, with the idea of buying it and going to port injection, but with the Weber bodies providing the butterflies. 

 

[AustrianVespaGuy]

2 hours ago, squirt46 said:

I was/am targeting a 'stealth' system such that it would appear to be a period appropriate hotrodded engine using Weber carbs.

=>

BMW M10 Heritage Throttle Body Kit

STORE.JENVEY.CO.UK

---

BMW Individual Throttle Body (ITB) kit for fuel injecting your BMW M10 4 cylinder from Jenvey Dynamics includes a pair of TDP45 Heritage throttle bodies,a Jenvey Dynamics EFI inlet manifold and 40mm long airhorns. Jenvey throttle bodies and all Jenvey throttle body...

 

Just gotta spend the money but then you get EXACTLY what you want. . .

[Mark92131]

2 hours ago, squirt46 said:

https://www.atpower.com/products/magneti-marelli-pico-330cc-m-iwp043-fuel-injector

 

The fuel injector you referenced is designed for top-feed, but you have them mounted under the carbs?  They also appear to be EV6 style.  Would it be possible to machine your injector bungs to accept EV1 style injectors and then find the appropriate flow rate for your application?  The longer EV1 injectors should protrude farther into the air flow and may help with your pooling issues.  I am assuming the SDS ECU is driving High impedance injectors.  So if you want 20lbs, maybe a Bosch 0-280-150-503 is a high impedance EV1 injector that will flow 20.15lbs at 3 bar.  Lots of EV1 options to help you dial it in.

 

Published Injector Data - Injector-Rehab

INJECTOR-REHAB.COM

---

Published Fuel Injector Data

 

Just a thought.

 

Mark92131

[TobyB]

I really don't think you're going to be able to find electronic injectors in the 'rail' form factor that are rated much below

2.5 bar.  The ONLY ones I've come across on this continent are the GM version, and they're set up to 

sit inside the induction passageway-   and they're big enough to almost block the throat of a DCOE!

I recall looking at the flow pattern of the GM injectors, and it was pretty good- looked a bit like a hose nozzle.

 

At less than a bar, the typical 2.5 bar injector looks like post nasal drip.  Pretty terrible for atomization.

 

In your shoes, I think I'd look for a 20 lb/ hr- ish injector in the pico form factor at 3 bar, or similar.

Hey- thanks, Mark- that looks like about what you have.  So, just 

change the fuel pump.  Run it at 3 bar, and see what happens.  And yes, there will be some puddling at idle,

but that's also true of plenum carbs, so with some tuning, you might be able to mitigate its effects...

 

Alternately, I keep the Sherryberg page open on AliBabaLitetakeallyourmoneysyesyesyes

https://www.aliexpress.com/w/wholesale-throttle-bodies.html?SearchText=throttle+bodies&catId=0&initiative_id=SB_20230426164211&spm=a2g0o.best.1000002.0&trafficChannel=main&g=y&page=2

because dayumn, I don't think I could buy the fittings for what a set of throttle bodies cost, there...

 

t

not so serious about the Burg of Sherry.

[jimk]

Ya can't avoid puddling when spraying on a throat that has no flow.  And that is no flow in semi sequential and batch.

[squirt46]

Thanks to all; just got a note back from RHD Enginneering in Australia:  "yes our manifolds do have the weber bolt pattern, yes we can sell you just the manifolds and fuel rail, price $280usd and $65 respectively (plus post to Canada about $90)". 

I've asked them for an approximate length of their manifold, so we can see if our approach (using the DCOEs for their butterflies) will fit.

Put the rad/hoses/alternator/fan belt/etc. back in today and were able to start it and let it idle for an extensive period of time.  Big oil leak from the valve cover; looks like there's a transmission oil leak (not happy about that one!).  Adjusted the fuel pressure to 13 psi (roughly:  the increments are about 2 psi and the gauge is oil filled but the needle still bounces.  Still got got puddling, but we're making progress.  And if it all goes to heck, RHD might be the optimum back-up.

[squirt46]

Note from RDH:  "intake manifolds are about 115mm long (from the head face)

Rama

Looks tight, but we'll try to dummy up a spacer next week to get a feel for how tight.

[Dudeland]

The RHD product is a nice-looking kit.  Does it fit with a standard brake booster?

 

Does it handle boost I wonder? 

 

 

 

 

 

BMW M10 Complete ITB Kit Includes Gloss Carbon Air Box - Racehead Engineering

RACEHEAD.COM.AU

---

Full bolt on ITB kit BMW M10, vacuum accumulator and all the associated fittings and hose tails, gloss carbon airbox. Proven Performance.

 

 

Edited April 29, 2023 by Dudeland

[tzei]

@squirt46 Was/is your set up like one small(ish) ”fuel rail” on top of a left frame rain and from there about 50 cm hoses to the injectors?

[xr4tic]

On 4/28/2023 at 11:28 PM, squirt46 said:

Note from RDH:  "intake manifolds are about 115mm long (from the head face)

 

Rama

 

Looks tight, but we'll try to dummy up a spacer next week to get a feel for how tight.

 

Let me know if you want some measurements/pictures, mine is sitting in the basement.  The manifold is ~4 5/8" center to center, with a slight angle.

 

On 4/29/2023 at 6:57 AM, Dudeland said:

The RHD product is a nice-looking kit.  Does it fit with a standard brake booster?

 

Does it handle boost I wonder? 

 

I asked him if it handled boost, he didn't answer.  He did say it *should* clear the booster.  It's about 12" overall length.  I suspect worst case is that one of the trumpets will hit, but I'll find out (eventually)  Getting an air filter on it will probably be the hard part.

[squirt46]

tzei:  we've got a solid chunk of aluminum (except for all the holes...) bolted on to a bracket just below where the battery mounts on the drivers side.  From there we've run stainless steel braided hoses up to the injectors on the underside of the DCOE bodies.   Have a look-see at the photo I posted Dec. 18/22, on page six of this thread, for the red anodized manifold piece.  We've replaced the fixed fuel pressure regulator on the end with an adjustable one, so thing will look different in a subsequent photo.

[squirt46]

xrtic:  thanks for the photo and offer of further measurements.  Good fortune developing an air cleaner systems.  We've got 90 degree ells from Ireland Engineering on the intakes to our DCOEs, and 'pod' style filters on them.

I'm going to pull one of our carbs and stop by to see Ross at Simple Digital Systems to see if he has any suggestions, and to ensure that I'm using the correct phrasing when referencing our injectors, as I figure I'll drop a pile of e-mails to the various sources, asking if their injectors can measure and work at 13 psi (or anything close). 

[Tommy]

5 hours ago, squirt46 said:

xrtic:  thanks for the photo and offer of further measurements.  Good fortune developing an air cleaner systems.  We've got 90 degree ells from Ireland Engineering on the intakes to our DCOEs, and 'pod' style filters on them.

I'm going to pull one of our carbs and stop by to see Ross at Simple Digital Systems to see if he has any suggestions, and to ensure that I'm using the correct phrasing when referencing our injectors, as I figure I'll drop a pile of e-mails to the various sources, asking if their injectors can measure and work at 13 psi (or anything close). 

Still fixated to 13psi... it doesn't seem to make a difference what is said here but maybe Ross can turn your head.

[squirt46]

Good Grief!  Tommy:  we're trying to build a throttle body injection system, not port injection.  If we end up moving to port injection, by (for example) installing the RHD Engineering manifold with it's port injectors, then we'll use the pressure that is appropriate for port injection. 

However, throttle body (e.g. General Motors in the 80s and into the 90s; Patton Machine's current kits for converting SU/Stromberg et al carburetors to EFI) injection uses pressures in the 12 to 14 psi range.

My understanding is that Detroit adopted the TBI approach initially as it required minimal retooling:  effectively, replace the carburetor and fueling pump/lines, and you had fuel injection.

Where I screwed up (with my minimal knowledge) was in not recognizing that the injectors that GM used were completely different than modern injectors  (Patton uses GM injectors).  I'm guessing here, but I expect that GM did their original injector design based on using the low pressures so they could keep their initial systems low cost & simple.  However, the fact that they were injecting the fuel upstream of the throttle plates such that the spray could be hitting the plates may also have impacted their pressure choice and injector design. 

My problem now is that the injector bosses welded onto the DCOE bodies will only accept current high pressure injectors, and I do not have the skills/equipment/money to machine up something that could accept a GM injector and then be successfully welded onto the DCOE body - have a look at the Patton Engineering page for the beautiful adapter that he's designed and that can be bolted onto the SU/Stromberg body.      

I expect that an adapter could be designed to accept the GM injector and be welded onto the underside of a DCOE body, but (per above) that certainly exceeds my abilities and level of commitment.

My understanding is that the minimum pressure that modern injectors are designed to operate at (i.e. open and close reliably as directed by the ECU) won't drop as low as the GM etc. pressure.  And - per the above - I have no idea if there is an inherent problem (gasoline dropping out as a liquid as it hits the throttle plate?  other issues?) with going above GM's 12-14 psi range. 

I'm not sure of the manufacture/model  of my injectors, and need to find out what their minimum pressure is; have a look to see if I can find a modern injector that has a lower minimum operating pressure; etc.

We'll spend some time  trying to get what we have running, but I'm thinking that I need to identify my injectors (and find out their minimum design pressure) and then try adjusting the fuel pressure back up to that minimum and see what the effects are. 

I would appreciate any suggestions based on knowledge. 

[squirt46]

I'm thinking again:  if I can determine the minimum design pressure for our current injectors, and we still have fuel puddling concerns, then modifying the bodies to allow different DCOE venturis to be installed might increase the air flow to help with fuel vapourization (the injector location means we can't use the normal DCOE choke/venturi system)