Twinductionâ„¢ Injection system for Log Burners

[xctasy]

Hey, here's what I've been doing lately.

While having a good hard look at the log head, and milling over indepedent runner carb systems like triple Holley 2300's and the like, I started looking at more modern systems.

I've always liked the simplicity of the log 144-250 engines. They are very strong, very reliable engines that suffer from a restrictive intake runner design. So I looked at what I could do to build a good flowing log head without cutting the log off and welding a plate to it, like what the old guys used to do in Australia in the 60's and early 70's, before 2V's and Cross-flows.

So the idea I've come up with is to use the stock log head, and build a jig which allows the log to still remain in place, but get some savage modifications. This involves the following four things.

1. The drilling of 12 pilot holes, indexed in position against the two casting plugs at end of each extremity of the beloved log intake. 6 are for the Bosch/Siemens injectors used in GM 3800 engines. The other 6 are for half a dozen stub stacks or trumpets, which area as big as they can possibly be, 40 mm in internal diameter.

Each of these holes is enlarged die grinder, and then finished by plung drilling using a tungstan carbide boring bar.

2. These holes are then tapped with a die to allow the bosses of the injector to be placed in the heads intake runners. (There is also a pre located pod for the extruded aluminum fuel rail, which holds the injectors in place)

3. The six 40 mm ID intake trumpets are screwed into the intake manifold, with no slides or throttles at all.

4. The real good part is that there is no throttle slides at all. This is a MAP driven system, which runs off two throttle bodies mounted adjacent the groups of each group three intake trumpets. Hence the Twinductionâ„¢ label. These are mounted on a combined upper plenumb, reminiceint of the Rover 3500 Vitesse/ Holden SS Group A 'Walkinshaw' efforts which used twin throttle body set-ups in there homologation Group A forms in the late 1980's. This allows a range of existing Delco P4 (Melcal or Calpak units from GM 3800 V6's)/ EEC / Haltech / Motec / Zyteck /SDS/ Megasquirt engine management systems to work.

I favor the Delco P4 in this part of the world, as it is not saddled with some of the nasty dual pulse ingition set-ups which make post 96 Aussie 4.0 liter sixes such a beggar to tune with big cams. It also offers the opportunity to run a distributor-less ignition system, making more space for a supercharger of some kind on the left hand side of the engine.

Advantages:-

1. This set-up allows the intake manifolding to be optimised for peak power. Don't expect Tunned EFI-style low-end grunt, there isn't the space for long sweeping 4.9/5.0/5.8 EFI-style runners.

2. It will allow sequential or bank fire EFI to be used with a minimum of hassle, and will produce the best fuel mapping for anyone wanting to really work that Log headed anachronisim in to a Log-Burning normally aspirated, supercharged, or turboed small six.

3. The good later heads, with good size valves and induction hardened seats or hardened inserts, can be use. No 2V heads needed.


Once I get the critical dimensions sorted out, and a 200 buck produced, I'll spill the beans on how it all goes together.

 

[Asa]

sounds good man, can't wait to see/hear more

Advantages:-

any disadvantages you can think of?

 

[Bort62]

Essentially the same thing I am doing, but I am opting for a single TB mounted to the carb inlet. Ive got a complete Gm 2.8L w/ infuction I am using for parts.

I don't see any real advantage to the added runners(trumpets). And even so, it would be much simpler to run them into a single plenum.

I am a P4 fan myself, and have all the parts just need to do it.

One of these days. T5 first.

 

[Bort62]

The dis advantages are primarily that it will be a hassle to build.

Also, the log casting is not thick enough to support injector bosses without adding extra material.

If you run them directly into the runners you may avoid this problem, but you might start having some clearance issues.

Its just a lot of work, that's all. No one part of it is rediculous, but all added up its alot of time and grunt work. Not your average shadetree jobber.

 

[addo]

Still cheaper to knock up a pattern, cast a new manifold or adapter, and hook it all into a 2V head.

 

[xctasy]

Disadvantages.

I think Bort62 coverd it.


1. I looked at the intake trumpets. It's not an issue about the thickness of the casting. It will be threaded in with a large BSP thread, practically an interferance fit. Easy to die-grind, then no linkage to deal with. But knowing how to make a jig that can allow a Backyard Bob to do it is another step up. Its just a 60 degree from vertical plunge at the log, and the spacings are fairly simple to index, but there's a few tricks to it.

2. Expertise. I've often said that if you give people enough rope with out knowing the laws of injection, they'll hang themselves. So there is a risk things can turn to custard. I have no real issues with a lower perfroamnce 130 hp 200 running TBI, but people do want more.

Any issues about the nature of the work is going to have to be based on someone doing it, and sharing it, no closed shop. If people want hot sixes for small quids, they have to share all, not keep it to themselves.

Presently, in Aussie, the earlier injected 1988 to 1995 Holden Commodore 3.8 V6's have between 168 to 177 hp, depending on if its a clean Aussie spec catalyst model, or a 'dirty' NZ-spec version. And there are chips galore for it. The ignition, coil-over plug ignition, and general availibilty is just brilliant. The Buick Super Charged 3800 ones were at the 205 hp level, still with the Delco computer.

3. Time again, the issue of setting up the throttle levers for triple carbs seam to cause problems. The idea of running twin throttle bodies is negotiable, but I see it as an important inclusion for performance. This is a bit techie, I guess. Plenty of people will start thinking the same about twin carbs as with twin throttle bodies. What if they fall out of synch, how will the throttle position sensor be wired to set curb idle and wide open throttle.

4. Then there is the return line and fuel tank issues. I hate the idea that an EFI vehicle needs only two failsafe devices, a crash 'gravity' switch, and the electronics. I've heard about the EFI pumps, and Holley fuel pumps being wired in a dangerous way, spilling fuel in an accident. This is where the system must follow a benchmark EFI donar vehicle.

5. Welding gas tanks, getting the lines crossed with brake lines, exhasts or powered wires.

6. The faults EFI vehicles exhibit. How do you trouble shoot an installation that has been hacked, and is no longer your dads Oldsmobile 88's?.

7. There is more to go wrong.


But we all are more conversant with the technology. There is more on line help for EFI than carbs. Carbs are good things, but there is a wealth that can go wrong with them, too.

I'm a hater of electronics in many ways, but theres a furrow field of tough sixes with poeple asking the same questions, over and over, not believing they can do it. We've got to change that.

I also have some LPG ideas, and I think the turbo six mob in America possibly should look at EFI first, since LP Gas is not as cheap or favourable in the USA. Impco have just locked out the 'hayseed technical bulletins' which allowed everyone to see how to do there own electronic hook-ups, and have purchased the Italian BSC company, who have had electronic LP Gas set ups since 1995. So information is going to get locked out from us.

Ever tried to get a manual on Toyota Camry pistons, rods, bearings or electronics? Can't get the info, its all intellectual property, paid for by them, and not for sharing. This is where things are heading, and we've got to get EFI technology by the private parts, and make it work from Detroit to Dunedin. If Jack Collins can do it, so can we!

 

[Bort62]

I have a pretty intimate understanding of the delco port injection systems if you need a hand.

 

[xctasy]

I'd like to take you up on that. Thanks.

I've got the centre spacings and extruded injector rail pretty well covered. I'm interested in massaging the fuel tables as a bankfire 123, 456 out fit, and run a seventh injector near the original carb base.

The ignition needs to follow the CCC Buick process

I spent 7 years behind my old companies GM 3800 (Holden Commodore, an intermediate RWD Opel), and the initial enrichment is always a couple of engine revolutions slow, but I loved the crisp power delivery. Our 120 000 mile machine could still lay down 17 second flat quarter miles, with 177 hp and 1.7 tonnes to drag around. (220 pounds of pig iron in the back to settle the May's meter we used for road roughness surveys).

 

[Bort62]

Well, the computer fuel and spark tables will have to be completely re-done for this application, but that is trivial.

As far as the ignition, that's pretty easy. Use a GM TPI module (or msd 6AL etc) and use it to fire a duraspark.

Disengage all the vac advance and centrifugal advance on the duraspark, and you are set.

the electronics part of it is all pretty simple. It's the fabrication that is tricky.

btw, why a 7th injector ? that serves absolutely - purpose. Also the bank fire systems fire simultaneously so there is no reason to distinguish there.

 

[CoupeBoy]

As far as the ignition, that's pretty easy. Use a GM TPI module (or msd 6AL etc) and use it to fire a duraspark.

Disengage all the vac advance and centrifugal advance on the duraspark, and you are set.

This is a little confusing, to me anyhow, why would you need a GM module and a duraspark module?

I have a GM HEI module working with my DII dizzy now, with no need for a ford module. And I understand that possibly the TBI ign module might not work the same as the old school module I have, but with the advance locked out of the dizzy I think the ford module will not be up to par to keep things in time, so unless the GM ECM can adjust the timing signal to resend back to the ford module I think there might be issues.

Also I thought the MSD 6A family of controllers only converted the square signal from the DII to a ground signal to control the coil OFF/FIRE? I thought you had to spend more $$ to get up to the digital 6 series to get timing control?

Of course all my rambling is useless if you meant that you should use a Duraspark to trigger a GM TPI or 6A.

-ron

 

[Bort62]

I meant you use a GM TPI HEI module to trigger the DII dizzy.

You lock out all the built in advance and let the computer do it's thing.

 

[Bort62]

If you can give me a head with 6 mounted injectors, a fuel rail, and a mounted Throttle body - The rest is childs play. Wouldnt take more than a day to get running with parts I have in my garage.

I just havent had the time or the inclination to do that part yet. It involves a little more legwork and intuition than I have been willing to give it lately.That will be the next project after I get this current motor into the car.

One thing I have contemplated is using the fuel rail frm something like a BMW or Nissan 6. Have to go out with a measureing tape and see what they got to offer.

Keeping the fabrication of parts to a m inimum is key to keeping it simple. the more you can borrow frm other applications, the better off you will be.

 

[xctasy]

The injector rail has to be alloy extrusion to locate the type of injector used. I don't like brazed rails out of tube, or having to find another rail which would then shove the injectors in the wrong position. The injectors are tilted and then located by the aluminum extrusion, just as per GM parctice. There is no other rail I can use.

The injectors are actually too close to the intake valve. The alloy head cross flow has it's injectors about an inch and a half further away, and get more spray atomisation as a result.

The Commodore engine runs a coil over plug, distributorless ingition system , as per post 1988 front drive GM 3800 compacts and intermediates. With a bushed distrubtor shaft, rather like the last 5.0 and 4.0 Explorer set ups, I'd like to use the even fire ignition system, but I'm not sure how I index the ignition pulses. Should be the same.


The seventh injector is just to cold enrich.

 

[Bort62]

The cold encrich is 100% useless as the $8D Mask has cold enrichment procedures already inclused. That's the beautfy of programmable efi is you don't have to screw around with stupid stuff like that.

Also, there is no known way to fire a DIS system like you describe with a p4 ECM. You would have to use something like a Northstar ECM with the northstar DIS module. Ive been down this road before.

As far as the injector spacing, it's fairly unimportant Get 6 injectors mounted somewhere in the log and it will work fine. Weather it be ontop of the valve or otherwise.

 

[xctasy]

The 88 to date GM 3800 has a six coil system which is DIS-type in its operation. It's just like a normal disy, but re-aranged with a crank trigger, and the igniton ramps are built in to the calpack, I think.

Whatever, its works very well. I'll post the set up when I find it. It's little different to the Buick set-up.


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