Spittybug - Designs for converting stock setup to EFI

[lazabby]

So you're taking orders for EFI conversions...? Houston is not too far from Dallas...

We've learned a lot with my conversion. I think Owen just about has all the bugs worked out. Don't know if he's taking orders or not. But it definitely seems worth it.

[opethmike]

Next logical step: heads, cams, exhaust

[Spittybug]

I'll let Shannon chime in and upload some pictures of his finished product, but we drove it around today and used VE Analyze live to tune it a bit. It didn't need much at all; the base tune I provided from my car was fairly close. It starts RIGHT up, idles nice and evenly and drives without hiccups, backfires or other glitches. We still have it sitting at 14.1 air/fuel across the board and no acceleration enhancement yet, but driving it was fine. After addressing the above it will increase the performance even more.

Right now it is still using the distributor for timing (although vacuum is not connected, so that there would improve things a bit too) and must be adjusted to run full EFI spark as well as fuel. Shannon has the choice of going all-in or leaving the distributor in charge and we can simply put the vacuum solenoid back in place (easy) and have it controlled by Megasquirt (open/closed based on throttle and coolant temperature, just like the microswitch and thermovacuumthingy in the stock setup). I'm still playing around with my advance table but I think it is close enough to share at this point.

The second car, which wasn't going to undergo conversion until we proved the first, is also running, albeit with some odd problem that I can't associate with Megasquirt. Ian's manifold vacuum is not nearly as low as it should be (80 vs. 40ish on the MS load scale in kPa) and we're perplexed. We have confirmed with an analog gauge as well as MS. The unit responds to pulling a vacuum manually, so the MAP sensor isn't bad. OK, opening the butterflies (engine warm, idle air now off) increases the vacuum (indicating that it was just not getting any air and couldn't stay running) to where I would want it to be, but this is at >1500rpm. We can't get the combination of proper rpm and good low manifold vacuum. We have some suspicion about his stock distributor as we actually saw the amount of advance increasing as we brought the rpms down (WITHOUT the vacuum advance connected). Some odd stuff going on, but clearly mechanical in nature since megasquirt plays no role in the idle speed which is a function of the quantity of air coming in. One cannot tune anything fuel-wise until the idle is fixed. The rule of thumb is to set the idle where the manifold vacuum is at its strongest. We've got some head scratching to do here. Oh, at higher rpm and less engine manifold, it runs pretty nicely too!

So! Fuel rails, idle air block & valve, MS unit and an LC-1 controller all replacing K-jet and all of it's wiring and controls. Looks almost stock except for the idle air block. We learned tricks on the rail mounting angles, injector heights, fuel hose routing and all of the right fittings for a tight system. Who's next?

[lazabby]

Owen was right. It starts very nicely and runs very well. I plan to run it more later this week and let the Megasquirt work on the autotune. Here are a couple of pictures showing the fuel rails and injectors.

[AdmiralSenn]

Owen, did you ever find a way to handle a throttle position sensor? I know it's not necessary for a stock setup but I'd like to have one on mine for some future expansion work I'm planning out.

I saw a picture of one you had earlier that was on a stock throttle spool. Did that one work okay (and if so, what was it)? It looks like it was mounted better than my attempt.

[Spittybug]

Nope. Ditched it. The stock setup just isn't conducive to one; although Bitsnycmaster (Dave M.) suggested a pedal sensor. It really isn't needed. By using MAP based acceleration enhancement, or better yet, the enhanced acceleration enhancement (is that redundant?) that I'm currently learning about, the TPS sensor isn't required. Of course, if some enterprising individual were to figure one out, that is just cream on the dessert!

Of course, in the case of a very wild cam (not like mild stage II) there is difficulty in using vacuum based fueling algorithms because of the valve overlap. In that case the best course of action is throttle based fueling. THEN one would need a throttle sensor.

[opethmike]

Of course, in the case of a very wild cam (not like mild stage II) there is difficulty in using vacuum based fueling algorithms because of the valve overlap. In that case the best course of action is throttle based fueling. THEN one would need a throttle sensor.

As I have found out!

[Farrar]

Bitsnycmaster (Dave M.) suggested a pedal sensor.

This is what I would go with.

(...eventually...)

[dmc6960]

Huh? You "stock" folks aren't using a TPS? Even if your using MAP based AE, I think that may come back to bite you. What about attaching something to the top of the throttle spool. I saw that done by one of the first EFI'ers whom I dont remember his name or screen name.

[DARCOM]

That might be me with the tps on the spool.