Best Engine Management...

[mushroom_toy]

Another option that the brains over at the Megasquirt forum figured out is to use a single MAP sensor for each runner and then use a clever electrical circuit to always take the signal from the sensor reading the lowest MAP level and send that to the ECU. The reason for this is that the runner with the lowest MAP will be the one that is closest to it's intake cycle, which is where you want to take reading. With a common plenum the runners are all at the same pressure, but not so with ITBs. The circuit to do this is amazingly simple and I think you can even still get all the parts at Radio Shack (minus the MAP sensors). I'll have to dig up a link to the circuit later and I'll also get some pics of the MAP sensor box I built. It's really neat stuff.


C|

Yeah definitely find that circuit if you can I might try that. Yeah the gsxr tbs are around 42mm I think, so it should work reasonably well, also they were already set up amd spaced with spacers so the almost matched up perfectly to the a series manifold, when I had my runners welded on, I just had the runners conform to the tbs instead of lengthening the tb spacing, so theyre pretty much almost stock spacing, so there is only 1 adjustment to adjust all 4 together, or you can adjust each one seperately, but i dont plan on doing that since each individual tb should have been set right from the factory and im pretty sure they havent been messed with.

ill try to take and post some pics up soon of my tb setup, I read a lot of your pages on pp originally, but Id still like you to give any suggestions you might have when you see mine.

[cygnus x-1]

Yeah definitely find that circuit if you can I might try that. Yeah the gsxr tbs are around 42mm I think, so it should work reasonably well, also they were already set up amd spaced with spacers so the almost matched up perfectly to the a series manifold, when I had my runners welded on, I just had the runners conform to the tbs instead of lengthening the tb spacing, so theyre pretty much almost stock spacing, so there is only 1 adjustment to adjust all 4 together, or you can adjust each one seperately, but i dont plan on doing that since each individual tb should have been set right from the factory and im pretty sure they havent been messed with.

ill try to take and post some pics up soon of my tb setup, I read a lot of your pages on pp originally, but Id still like you to give any suggestions you might have when you see mine.

Another thing that helps if you can do it is to have the cable drive the TBs from the middle (between cyls 2 and 3) instead of from the end (1 or 4). With paired TBs it's not such a big deal but with separates, if you drive the throttle from one end you have to go through 3 linkages to get to the other end. That's 3 points where the system can flex and create a difference in throttle opening. From the center you only have one or two points where flex can occur.
Anyway it sounds like you've got the mechanics worked out.


This is kind of a cryptic schematic but the important stuff is there. I can interpret it later if it doesn't make sense (just about to head home from work so I'm in kind of a rush).




Basically what it does is to use the diodes to select the lowest voltage which then get amplified by an Op-amp (triangle thing). I'll get some pictures up of the one I made later.


C|

[mushroom_toy]

^Sound good...i cant see your pic. XD

[guaynabo89]

open yer eyes.



It says its download, not a picture though. only megasquirt forum members can see it I think.

[cygnus x-1]

^Sound good...i cant see your pic. XD

Uhhh.... hmmm. Wait, here it is.








Ok, it's fixed now. Not sure what happened. It worked when I first posted it.



C|

[mushroom_toy]

Ah ok I see it, so where would be a good place to tap it, Id love to tap the runners but theyre short, and Id rather not tap the manifold since it isnt replaceable, I was gonna ad some runners on the opposite side of the tbs, so I could tap the runner there right? Since it will be pullling vacuum from there?

[cygnus x-1]

Ah ok I see it, so where would be a good place to tap it, Id love to tap the runners but theyre short, and Id rather not tap the manifold since it isnt replaceable, I was gonna ad some runners on the opposite side of the tbs, so I could tap the runner there right? Since it will be pullling vacuum from there?

You can tap for a MAP signal anywhere between the throttle plates and the valves. Really doesn't matter exactly where though. The TBs should have at least one vac port on them already right? Those would be perfect.


C|

[mushroom_toy]

You can tap for a MAP signal anywhere between the throttle plates and the valves. Really doesn't matter exactly where though. The TBs should have at least one vac port on them already right? Those would be perfect.


C|

Ah ok yeah I would have to tap into the vac line setup im already running between the ports....before I got the tbs someone had already jb welded and put vacuum line fittings in all of the tb injector holes, so I guess ill have to tap there.

[Civic Accord Honda]

pics of tbs please :p