The Stovebolt Site Forums The Shop Area The HiPo Shop 261 EFI

My Stovebolt self tuning EFI system that I have builtfor the 261 than I am building.

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Thats nice, Is it a injector system.

It is a self tuning EFI system (FAST EZ-EFI) with custom injector manifolds/plenums on top of GM TBI throttles and custom adapters to fit a 2-15/16 bolt pattern 1 barrel flange.

By self-tuning I assume you mean closed loop with a sensor or 2?
It won't necessarily get as close as you could with carburetors. The common plenum makes the sensor reading only partially representative of the mixture in each pair.
What exhaust?

How about posting some dyno run documentation and controlled route road tests showing the power and/or fuel mileage gains compared to carburetion?
Jerry

@panic.

Closed loop and actually, it can get close if not closer than a carb and be able to adjust for altitude as the system uses a map sensor, temp sensor and wide band 02 sensor to adjust as needed. The wide band 02 would read both manifolds, which are Fenton headers (if merged, which will be on the engine build). To get exact cylinder mixture, a temp probe would be required (K wire thermocouple if I want to get fancy to data log the engine as it runs) rather than pull plugs and visually check.

@Hotrod Lincoln

Too early for the engine that this is going on is is a current build with the block at the machine shop, so no dyno numbers as of yet. It most likely won't see an engine dyno, as it isn't a power seeking experiment and the $1000 for a full day isn't something that I have to spend for an engineering exercise. Road test will happen once the chassis for this engine is finalized (currently, the most has no intended home. I just like the Stovebolt engines and have been tuning/building them for 30 years (them and almost any other engine). The control system itself is a proven one (COMP CAMS FAST EZ-EFI). The build itself is just a means to occupy my idle hands and mind.

Hmmmm- - - - -if dyno work is that expensive these days I really need to get mine back into operation. It's been in storage for at least 15 years. I dyno tuned just about every round track engine I built.
Jerry

rhussjr Wow now if that gets some real economy,that will be impressive. I assume you will still be at about 7.5 to 1 c/r. Know of any reasonable way to raise it ?? Would like to have 10 to 1 !!

"Good grief, Charlie Brown!"

I am on the edge of my seat hoping that you learn something new about gaining significant performance gains with one of these tractor engines (essentially).
I do have some serious concerns about going with dual injectors though. It seems that would compound the effort to tune this setup by a factor of 2 if not more.

Can the 2 injectors be adjusted separately?
Each adds mix to all cylinders, but the intakes are grouped differently: left FI serves 1-2 and 3, right FI serves 4 and 5-6, but the exhaust grouping separates 1-2-3 and 4-5-6 completely. Reading each manifold will give you data from all cylinders because of the plenum.
How will it do cylinder to cylinder distribution?

52 carl You got that right,tractor engine...we are locked into lopo world. That 100,000$ turboed super 261 what?? 750 horse was a good example of silk purse out of a sows ear !!!

This is the HiPo shop. We are boys playing with toys without babysitters watching us.
I say, if a guy wants to try to build something using parts out of an Erector Set to build a Lincoln Log cabin, why, that's his bidness.
We learn from our mistakes. As long as the OP is footing the bill, why should we care? Worst case scenario for us is we get free lessons.

As I have pointed out many times, this is the HiPo Forum and unless what is being proposed is a danger to the OP or others, snide remarks, criticisms and general overall bulling is totally inappropriate. If the gentleman wants to mount a leaf blower on top of the Rochester 1bbl, it’s his choice and he doesn’t need to be picked on for doing it. That is the exact reason this thread was moved from the Engine Shop Forum to the HiPo Forum. Y’all play nice!

I'm interested in this build. I think that the EFI would be a great improvement to the overall driveability of any inline 6. With cold starts being a thing of past and being able to adjust to elevation changes it seems like a Win Win to me.

To address the questions about the injectors for 52Carl and distribution concerns for panic:
The injectors are batch fired and can be tuned out (turned off in configuration settings). Running a dual system (two throttle bodies), driven 1:1 just like a set of carbs, each throttle body will have a driven injector to distribute fuel as normal and a second driven or second batch. Since the system has two injector drivers, the second injector is driven and only comes into play when demand requires it. If I used the injectors from my base system (which are 100lb or 1050cc), they would be able to support up to 650hp. So I have elected to use a smaller 37.5lb injector (394cc) for the system, which are enough to support about 240hp (using all four driven at 80%). Essentially, all four can fire at a low duty cycle and increase output as load requires, especially if even small injectors are used.

Cylinder to cylinder distribution on these engines are always a concern and depending on the intake design, things will vary. If this was setup as a single unit (1 barrel), naturally cylinders 3 & 4 get more fuel. The advent of the 2x1 intakes helped alleviate some of this, but added complexity in tuning. Then with the 3x1 intakes, you got better distribution, but we all know this. I have actually plans to test and tune a 3x1 system and the components ready to go.

The invention of fuel injection (from the original mechanical) helped add hp, but has its complications. As things progressed, TBI, TPI/PFI, then GDI have made massive advancements in fuel control capabilities. So, I am merely using what newer technology I can to create a simple system that will provide some advantages over the old carbs on the 261 engine that I building. The better fuel atomization in itself will lend a hand when it comes to distribution issues. The closer you can get gas to being gas vapor, the less likely it will have flooding and fouling issues. The ECM will monitor that via the wideband (adding a secondary wideband monitor (or thermocouples) on each manifold prior to the merge, will help in tuning, but this is overkill as the motor itself will not require this amount of accuracy).

Now, just a little background on myself. I have done work in several fields over the years as an engineer and have been in the automotive field for more than 30+ years. My last job I helped develop a fuel management components and active cylinder displacement/deactivation components.

rhussjr,

Thanks for sharing your project with us.

I have a 58, 3100 with a 235 and a Rochester carburetor. Needless to say, I think there has to be a better way.

I’d like to go with the Holley Sniper, Autolite 1100, EFI. I’ve been doing some planning and I think I have all the details worked out except for one. The coolant temperature sensor for the EFI needs to be installed into the coolant jacket of the head. There is no place to install it in the stock head configuration. I’m not keen on drilling a hole in my perfectly good head for another port, especially with the head installed on the engine.

The installation instructions for the EFI unit clearly states that the sensor needs coolant flow over it. I do have a tee that I can use to install both temperature sensors into but that would eliminate the flow over the sensor. I’d like your opinion on how critical it is to have the coolant flow over the EFI temperature sensor vs being deadened at the tee installed in the head?

Others on here, who’s opinions I respect have advised against the tee installation.

Thanks in advance for any info you can offer.

Why not use sequential port injection? TBI has always been a really poor substitute for real fuel injection, even when it was first introduced in the 1980's.
Jerry

The guy from Kings Mountain who is selling on ebay (https://www.ebay.com/itm/274826263944). Howdy neighbor.

Fitech, Holley Sniper, Fast EZ EFI and other controllers have their pros and cons. Most of their R&D goes to the bigger market of V8 engines, Jeep 6 and marine.
I imagine it will be a long while for a proven turn-key total package for a Stovebolt comes on the market.
So, it's up to the adventurer.

One thing that bugs me is the heat off of the exhaust manifold affecting the longevity of the sensitive parts incorporated into the injector body.
I was wondering if it would be better to have a water cooled/heated intake manifold and heat shields to protect the EFI.
The issue of where to mount the coolant temperature sensor (D B Cooper's comment above) would be in the intake manifold.
It may be worth while to first do a temperature study in the engine compartment on a stock engine setup.
You know, the typical 90 degree summer day headed down to Myrtle Beach SC.

There are numerous locations on a stovebolt cylinder head to put a sensor that will be exposed to moving coolant. All it takes is a drill press and a pipe tap.
Jerry

http://www.langdonsstovebolt.com/store/#!/NEW-OEM-quality-Thermostat-housing-w-outlet-on-both-sides-for-216-235-261-&-GMC-Alum-With-Gasket/p/62857064/category=18665950

This is one solution for adding a sensor or relocating the sensor for the gauge. Given, the ECM will give a temp readout on the hand held programmer and has the ability to control an electric fan.

Thanks, that’s a great solution.

I can relocate the temp sensor for the gauge to the thermostat housing and put the EFI coolant temp sensor in the head.

I'm pulling for you.

rhussjr,

I spend way too much time on the gm tech forum (of which I I am one, for a while longer anyway!), don't think I brag about that system over there!
Many AMF/ DOD lifers fail before the 1'st oil change. Wound seem to be a manufacturing issue as failure rate much lower from 2017 to around 2020.

I seem to remember another Rube Goldberg project from the 1980's- - - -the Cadillac V8-6-4. A bunch of train drivers thought that was a good idea, too! How about the mid-1970's Vega high-silicon aluminum cylinder block with the acid-etched cylinder walls and the cast iron plated pistons? I made a bunch of money installing flanged cast iron sleeves and conventional pistons in those things!
LOL!
Jerry

You have 2 sensors above the throttle plate in your image.

One looks like an IAT and the other looks like a standard GM MAP sensor, but MAP is generally measured between the throttle plate and the cylinders.

What are those sensors?

My design is relative to magnetics and component weldability related to the GM GDI pump fill valve. Prior designs were bolted on and newer designs are laser welded. I dealt with the design flaws that were involved with welding 420 stainless steel to 17-4 (and 420 to 420). Redesign of the valve body allowed to welding 17-4 to 17-4 (no issues with root cracking, much easier to weld).


IAT sensor and AP are both above the throttle plate. The throttle body on my base system has the MAP above throttle valve, so I carried it over. Referencing it after throttle plate isn't an issue as it can be plumbed to do this.

rhussjr Do you do any tturbo work,an advisor said not to try for economy with turbos,do them for power. Turbo-cummins does both !! Maybe they have a bigger engineering departmennt the we are used to !!

Thank you for sharing this project. Please continue to do so.

I have been doing turbos for the past 25+ years in VW and diesel applications. One project was a compound turbo on a VW TDI that made mad torque. For gas applications, I did a VR6 with 617hp / 513lbft to the wheels back in the late 90's early 00's. You can do turbo for economy, but given most do for power as it is the main purpose as a power adder. Low boost for additional power and torque on a stovebolt (or any other motor) can be had with the right setup.

I think this is a cool project. Plenty ambitious, but cool.

As much as we poke fun at these “tractor engines”, I’ve often wondered what would have been possible in terms of performance/ longevity/ economy if one could solve some of the inherent issues with Stovebolts:

* Crummy fuel distribution
* Crummy drivelines they were used with
* Pre-PCV blow-by covering internal parts with sludge.

Yes, they don’t flow air very well. They are heavy. But they are simple, rugged, well-balanced, and generate plenty of usable torque even as they are.

The driveline issue has been largely solved for those willing to do the T5 swap. Plenty of folks have created serviceable PCV systems for their stovebolt. Fuel delivery/ distribution seemingly has much room for improvement. Aside from the side draft YH setup that is unobtainium…and a few theories I’ve seen about custom manifolds with side draft motorcycle carbs….your project seems to be the most serious effort I’ve seen in that direction.

I suspect it isn’t going to create a practical solution for “the rest of us”, but I’m interested to see what you learn.

That’s a Thickstun or Thickstun-replica manifold. I’ve read that the theory with those goofy looking things was to equalize the runner length, but I’ve never read anything that proves any benefit.

Did you select the Thickstun because of the runner length?

The degree of atomization and droplet size has been tunable for many decades, it's what an emulsion tube (and its functional equivalents under other names) adjusts. In many carburetors it's a sized series of holes, which is why CFM is not a perfect comparator of accuracy on a different engine.

Vizard demonstrated that engines starved for air (low VE) produce more power with larger droplets, and engines with excellent VE do better with finer mist. The reason: a fully vaporized molecule of gas is 400 times the volume of liquid, and displaces air in the charge mass.
The degree of vaporization also affects how mixture behaves in a manifold (fine mist has lower inertia), and at different vacuum and temperature levels.

The "Slant 6" intake runners are made in different length on purpose to broaden the torque range.

I like listening to David Vizard.

52 carl Just saw your comment about tractor engines,very true,I think they will run on coal oil too !! It is satisfying though to update to better stuff and get a durable,easy to work-on outfit.

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Subscribing!

Your last picture looks like a different year engine from your youtube video. Just curious.

Like Raphael, the artist who left a hidden self-portrait in his painting, I see you left one in your picture.

Started the prototype mounting plate for progressive / direct throttle linkage setups for 2x1 and 3x1 intakes.


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Ok, you're gonna need beta testers. I'm here if you need me.

That's nice beyond words. Best of luck (although luck really isn't required from what I see)

RonR