Spittybug #2329 Peugeot 604 manifold custom conversion

[Spittybug]

In this thread I'll post pictures and data files about the custom conversion of my car.

[Farrar]

Farrar

[Spittybug]

Here is my current .msq file for anyone interested. Stock engine internals, 19# injectors, full EFI and spark control. Running nicely, but still want to refine the cold start and warm up since we are now getting some colder mornings to worry about. The acceleration enhancement needs revisiting too, I just needed a break from it. While playing with it a while back I had times when it would buck or bog and other times where it would unexpectedly pin me to my seat (really good), but I didn't get to finish up tweaking. I think that is an area where collaboration would be helpful. I've also attached a log file for reference, but we seem to be limited in size to only very small ones....Sean, can we bump this up? Hope this helps someone.

[opethmike]

I'm currently using your VE table for my nearly stable idle, so it has already helped me

[Spittybug]

I finally got off my ass and started optimizing my tables. They are pretty good I think, but the ignition advance is a bit of a black art I think. I did some more internet searching and I think I may have initially configured things a bit off. Here are my new understandings:

• Static advance - how much a stock distributor is physically rotated to advance the spark. 13* BTDC. This is also the idle value to use since the idle micro switch prevents the vacuum advance from seing any vacuum at idle.
• Vacuum advance - Here is where I think I was off a bit. Our book says 5"Hg is 3*, 10"Hg is 10* and 15"Hg is 20*. This translates into a range between 50kPa and 83kPa on the Megasquirt tables. So immediately after idle, the vacuum advance is at its maximum of 20* until MAP hits 50kPa, then it decays down to 3* by the time MAP hits 83kPa. I had it ramping up, then down, but not giving up that much.
• Mechanical advance - Book says 1000 RPM no advance, 2000 RPM gets 10*, 3000 RPM gets 14* and 4000 RPM gets 20*. I've had some car savvy friends tell me that I can be more aggressive on this and get it "all in" by 2000, gaining performance. Any opinion on that?
• Maximum advance - Not listed in our book anywhere that I can see, but again using some online calculator tools I think we max out at about 37* based on our valves, bore and era of the engine. Too much to potentially lose with too much advance, so if I'm leaving some performance on the table being conservative, so be it!

So, in the "idle zone", 13* looks to be the number.

As you move "up" the kPa scale on the table (Y axis), it starts at a high value (13*static + 20*vac) right after idle and decreases to only 13*static by the time you get to 83kPa. Of course by then you've increased your RPMs and you never really hit these bins on the table.

As your RPMs are increasing at WOT, the base 13*static gets mechanical advance added to it up to a max of (13*static + 20*mech). As you ease off the gas and the load goes down (decreasing kPA), the vacuum advance starts coming back in (13*static + 20*mech + upto 20*vac) all subject to the maximum of about 37*.

At cruise, or light throttle with your kPA sitting mid-low and RPMs at ~2000, the advance is (13*static + 20*vac + 10*mech) subject to maximum of about 37*.

The biggest change this will mean for me is in the shape of the vacuum decay. For some reason I have 17* in my idle area too that I will change. Nice thing is I can do this with just a few keystrokes and then burn it to the ECU no problem. If I make a mistake the roll back feature is nice. After the new timing table is in I'll run around with the VE tuner running and let it recalculate VE levels to get the target AFR of 14.1 I have set across the board. I still may tweak that table to go lean in cruise or decel and go rich on acceleration, but I want the timing dialed in first.

If this ends up being an improvement I'll post the final table.

For the non EFI folks reading this, don't let it deter you if you are on the fence! It's actually fascinating to see how much control you actually have over the operation of your car and how much performance you can actually get. Once over the hurdle of fixing everything to get ready for EFI and the learning curve (which hopefully these forums are helping to reduce), this part is really rewarding and fun. Better yet, you don't even have to open the engine compartment; just use your laptop!

[Bitsyncmaster]

I had to add a little hysteresis the vacuum advance (turn off 100 RPM lower than the turn on) to prevent a jerking if your in gear at that RPM. So you would not want to do sudden advance with your ECU.

I still want to put a vacuum gage on my engine and see what values it sees at higher RPMs

[opethmike]

I would advise against keeping 14.1 for every cell. You'll be going rich when you don't need to (cruise), and going lean when you don't want to (WOT).

[Spittybug]

I would advise against keeping 14.1 for every cell. You'll be going rich when you don't need to (cruise), and going lean when you don't want to (WOT).

I shouldn't; the VE autotuner adjusts the amount of fuel based on the desired AFR. In other words, it should give me less fuel at cruise and more fuel at WOT, right? While I do indeed intend to alter the AFR table, since it is the target for the VE optimization, in theory I'd be close to stoicheometric under all circumstances as is.

[opethmike]

Yeah, but you don't always want stoich. Stoich is good for cruise, but under acceleration you are going to want more fueling.

See the MS doc:

http://www.msextra.com/doc/ms2extra/...anual.html#afr

Getting the fueling right in the areas that require more fuel will make your accel enrichment much easier to get right.

[Byrne H&A]

Hello,
Set the distributor via vacuum guage (advance slowly) at idle: expect about 18". At 2000-2500 RPM the vacuum guage should read 24-25". Byrne