Let’s find ideal throttle body for EFI conversion

[TheFieryMan]

In anticipation of my big conversion project this winter I’m doing lots of research to try and find the “ideal” parts for the project. Obviously I realize that different people have different ideas of what “ideal” is so let me give some context for what I’m planning. I’m doing a speeduino project and planning to use all Bosch sensors and electronics for ignition. I’m sticking primarily to new parts and not too interested in retrofitting other EFI Goldwing parts (besides possibly using the 85-86 runner elbows with the injector ports) I’m also planning to CAD design an intake plenum that incorporates applicable ports for sensors etc.

Bike is 82 naked Aspencade. I have a dedicated thread (https://www.ngwclub.com/forum/viewtopic.php?t=78221) but wanted to start a separate topic for this.

What I’m having trouble with in this early planning stage is a decent throttle body. The plan is to use a single throttle body. What size would you go with? I estimated 50mm or so but what would your ideal be? Having as many applicable sensors built in is great of course but I’m planning to run injectors close to each cylinder (like the factory locations for the 85/86 system).

What I’m finding is mostly cheap chinesium or ultra high end race parts. A regular factory automotive replacement is fine as long as it’s made by a decent brand.

So what would be your ideal within that context? Let’s discuss.

[TheFieryMan]

One thing I’m noticing is that it’s possible to get one with an Idle Air motor built in. That seems like it would solve some issues but I have no idea how they’re controlled. If its possible to control it with the speeduino that might be pretty sweet.

[theailer]

Looking at this thread with great anticipation
Speeduino seems to be able to control a couple of different idle controls:
https://wiki.speeduino.com/en/configuration/Idle

[TheFieryMan]

Looking at this thread with great anticipation
Speeduino seems to be able to control a couple of different idle controls:
https://wiki.speeduino.com/en/configuration/Idle

One of my goals with this project is to actually be able to give someone who wants to do this type of thing a somewhat straightforward semi-foolproof parts list and "how-to" so that we all dont have to spend 3 years getting it working enough to ride a little. Im planning on putting together some CAD files that people can use to replicate some of the custom parts themselves without all the trial and error. Well, at least trying to reduce the errors as much as possible.

[TheFieryMan]

Hey, what is the inner diameter of one standard carb on the GL1100? Im trying to figure out what diameter throttle body I should be looking for. I know that the airflow works differently from a carb to a throttle body but I am just trying to get a general idea of the diameter I should be looking for. So far i've been trying to find something in the 50mm-54mm size. I was also excluding TBs that didn't have an idle air valve built in but ive decided that it would be better to make a provision for one to be added on the Intake plenum itself. I think that will make it easier to change out if needed and it gives WAY more options for different TB options.

Has anyone done CFM measurements on the GL1100 intake or carbs?

[Rednaxs60]

Will be following your thread. Always interested in another EFI conversion.

I agree with your wanting to use newer components. Even an EFI upgrade for an '85/'86 GW CFI model will require some newer components primarily because of the lack of data for the older Honda components. Without component data there is a lot of experimentation to get the engine tune settings optimal.

You are considering a "single" throttle body for all four cylinders, approximately 50/55 mm? The air plenum for an '85/'86 GW CFI model is quite large in area, would think you would need an air plenum of similar size.

If you are going to use the injector holders, maybe consider the fuel rails as well.

The Speeduino will be good. There is a company in the US, openlogicefi: https://openlogicefi.com. Has some interesting Speeduino compatible designs with case/enclosure. I like the Pre-Ignition x4 Slim ECU Assembled kit - Fully Speeduino Compatible, as well as the Spark Gap X4 - Standalone Engine Management Kit. Both have the barometer sensor already installed. The Pre-ignition x4 is quite similar to the Speeduino interface board v0.4.4. Reasonably priced as well. The Spark Gap pinout specifies using high impedance injectors - will be contacting the company to clarify this. Should be able to use low impedance with a resistor block, the x4 can use low impedance or high impedance.

I would recommend using Hall Effect sensors instead of VR sensors. You can use a dual wheel trigger system. The '85/'86 crank 8 tooth trigger wheel works well.

You might consider getting an '85/'86 right side head with the camshaft extension for camshaft sensors. This would enable you to incorporate a camshaft sensor for a dual wheel configuration, and in the long term, allow you to consider sequential fuel and ignition. As long as you can find a position for a second engine rotational input operating at half crankshaft speed will do. The camshaft or half crank speed sensor is a good consideration. Allows the ECU to accurately do fuel, ignition and engine timing. With a single crankshaft sensor, the ECU is approximating the position of the cylinder TDCs, works well but using the camshaft sensor is a best practice even if you don't have sequential fuel and ignition. That is the reason Honda had two camshaft sensors on the '85/'86 GW FI models for semi-sequential fuel injection.

A good coil driver is the Bosch 211. Can control up to 4 ignition circuits, again future proofing the install.

You have probably seen the post by socrace. He used COP units - I have these installed on my '85 GW, work well in sequential ignition. More difficult to install on the '85/'86 FI models because of space. The dwell time for these are 1.5 ms for cranking and running. Spark duration that I use is 1.8 ms. These settings work well for these COP units. The COP units I use are: https://www.amazon.ca/dp/B07HNQTF2J?ref ... title&th=1

The GW CFI model coolant and air inlet temp sensors work just as well as any new sensors. These work well with the sensor readings set at:

Bias resistor value: 2490

0 degrees - 5896
20 degrees - 2500
80 degrees - 250

I use the Cherry Hall Effect sensor Cherry GS100701. Work well and easily installed for the crank and camshaft sensors. This eliminates the need for a VR conditioner board. Socrace found the camshaft VR sensor did not send a reliable signal to his new ECU because of the half speed, so did I. Resulted in a lot of sync losses, MS and Speeduino.

Map sensor. You will probably have a board installed MAP sensor. Socrace used a vacuum block, I followed suit. Run the four hoses into it (one from each cylinder) then one hose to the FPR, and board MAP sensor.

I mentioned the openlogicefi units have the both the baro and MAP sensors installed. The baro install future proofs your install. Once you get the engine tune done, you can enable the baro sensor. One more input to the ECU to assist in the engine tune.

The size of fuel injectors is worth spending time on. The '85/'86 GW CFI injectors are 285 or 315 cc/min injectors at 43 PSI 30 lb/min - work well for the entire engine operating range. Honda derates this to approximately 260 cc/min at 28 to 32 PSI fuel pressure. The '85/'86 injectors give an indication of the size to shoot for. You don't have to spend a lot of money on injectors as long as they are all the same and serviced. Recommend getting a set that has the operating data such as injector open time. In Speeduino this is the time to open the injector to fuel flowing, and closing time. It's added to the fuel calculation for injector pulse width. Once installed, you can adjust fuel pressure and required fuel to suit, nice aspect of being able to access the engine tune. The open time for the '85/'86 GW FI injectors is 0.8 ms.

There are a lot of older FI components that are still in production that work well and have stood the test of time. Coil drivers, coil packs, and such.

I have learned a lot about the engine tune as well. The engine operates in a very small MAP window for all operating scenarios. This is what I am working on now, adjusting spark and VE tables for good engine operation and performance by doing road trials.

Hope you find this post informative. Good luck.

Cheers

[ericheath]

Going from highly suspect memory, 75-77 had 32mm Venturi’s, 78-79 had 31mm and I think all 1100’s did as well. 1200’s were 32mm I believe but used considerably smaller intake runners and ports, around 17% smaller I think. The Valkyrie 1500 has 24mm I think.

[Rednaxs60]

Good morning. Have been researching the various Speeduino and Speeduino compatible ECUs that can be had. Did a post on on a thread in Classic GWs: https://classicgoldwings.com/threads/19 ... ost-231295. These units are getting smaller every day. There is a C2C - Compact 2 channel unit from DIY-EFI that is no bigger than a deck of cards, amazing. Intend to upgrade/change the Speeduino unit I am using because I want a unit for bench projects.

Have been looking into using Alpha-N fuelling instead of Speed Density (SD). This took me down the multi-port (point) fuel injection (MPFI) versus ITB road. I have an engine tune in development using Alpha-N for my 1200 GW FI model - had the engine operating on it yesterday. Going to investigate it because there is a very small MAP window that the engine operates in.

The difference between ITB and port fuel injection is primarily the location of the fuel injector(s) and what results from this. Research indicates that Alpha-N is a good fuelling strategy with ITBs, and SD with port fuel injection, although the new aftermarket ECUs allow for blended and switched fuel strategies.

Having mentioned the above, curious why you are going with an ITB(s) and not port fuel injection.

Cheers