Greetings,
I hate carbs! OK, there, I said it ... I have an HKS 700E and a 912UL that both use the Bing 64/32 series carbs, and I'm going to try to make an EFI replacement. I'll start with the HKS engine since I'm in the process of setting it up on an engine stand now. The plan is to make sure it's running OK with the carbs, then switch to a custom EFI.
I've got some experience with the megasquirt ECU, and I'm thinking the microsquirt will be more than capable of running EFI on these engines. In both cases, I'd leave the current stock EI alone, and only control EFI with the microsquirt. The plan would be to have two independent EFI systems for each engine.
The first thing I need to find is a good throttle body to replace the carb. Unfortunately, finding a universal TB that small is not nearly as easy as finding larger ones, and none of them seem to be in the US. 40mm is about the smallest I can find so far, and I think that would be a good size to shoot for. This is my leading pick at the moment- Single injector Port Throttle body Parallel Bore I like this one because it has an injector port built in, and it's not outrageously expensive. I'm completely open to inexpensive OEM TBs, but I've had a hard time figuring out what sizes they are, since they're usually specified for a particular vehicle. They also always have stuff I don't want on them.
For the HKS, I'd run one TB. The initial plan would be to have the single injector on the TB work with one microsquirt. Eventually, this would be the backup system, but it's easier to set up and test first. If testing goes well on that, I'd fabricate injector mounts at the cylinder end of the intake runner, and run the primary system using those two injectors.
My main question now is whether there's a better choice of TB? I know SDS makes some lovely parts for the 912, but they don't sell them separately. I do have a CNC mill, and could probably make everything but the actual TB if needed.
I guess I should also ask if there are any other bolt on EFI systems for these engines. I fear the price would be much higher than I'd want to pay, particularly since I'd enjoy the DIY process, but it doesn't hurt to ask.
Thanks,
Rusty
I hate carbs! OK, there, I said it ... I have an HKS 700E and a 912UL that both use the Bing 64/32 series carbs, and I'm going to try to make an EFI replacement. I'll start with the HKS engine since I'm in the process of setting it up on an engine stand now. The plan is to make sure it's running OK with the carbs, then switch to a custom EFI.
I've got some experience with the megasquirt ECU, and I'm thinking the microsquirt will be more than capable of running EFI on these engines. In both cases, I'd leave the current stock EI alone, and only control EFI with the microsquirt. The plan would be to have two independent EFI systems for each engine.
The first thing I need to find is a good throttle body to replace the carb. Unfortunately, finding a universal TB that small is not nearly as easy as finding larger ones, and none of them seem to be in the US. 40mm is about the smallest I can find so far, and I think that would be a good size to shoot for. This is my leading pick at the moment- Single injector Port Throttle body Parallel Bore I like this one because it has an injector port built in, and it's not outrageously expensive. I'm completely open to inexpensive OEM TBs, but I've had a hard time figuring out what sizes they are, since they're usually specified for a particular vehicle. They also always have stuff I don't want on them.
For the HKS, I'd run one TB. The initial plan would be to have the single injector on the TB work with one microsquirt. Eventually, this would be the backup system, but it's easier to set up and test first. If testing goes well on that, I'd fabricate injector mounts at the cylinder end of the intake runner, and run the primary system using those two injectors.
My main question now is whether there's a better choice of TB? I know SDS makes some lovely parts for the 912, but they don't sell them separately. I do have a CNC mill, and could probably make everything but the actual TB if needed.
I guess I should also ask if there are any other bolt on EFI systems for these engines. I fear the price would be much higher than I'd want to pay, particularly since I'd enjoy the DIY process, but it doesn't hurt to ask.
Thanks,
Rusty
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