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76 K5: Megasquirt EFI, Electric Fan, and ICON Coilovers

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Team208Motorsports said:
@sreidmx Seriously.... Post it up or email it. [email protected]
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That's awesome, thanks! I'll shoot you what I've got so far, messed around with it a little last night driving it around. Got some of it pretty close. I am a little concerned about one corner of the map, you'll see it when I send it over. The ve is cranked up over 100 and still running lean. I'm wondering if my injectors are undersized... Wouldn't surprise me, most calculations show me needing 80 lb/hr, I've only got 65's in there. Worst case I'll swap them out. I'll try to get some datalogs to go along with the tune if you wouldn't mind giving me some pointers there...

The other thing I'm thinking is that my ignition offset is off a bit. I got it lined up to match my balance marks, but I'm pretty sure my timing pointer isn't correct. It gets real unhappy if I give it more than 12-13° advance, which doesn't make much sense. Starts popping in the exhaust pretty bad at around 2500 if I push any more timing.
 
Standard gm crate motor internals and heads, RPM Air Gap intake, Holley tbi, comp cams x4262h camshaft, full length headers.
 
I've been running Megasquirt on my K5 for a lot of years. Let me know if any of my tables would be helpful. VE should be similar even with TB vs MP, not close enough to run right, but maybe for sanity checks or smoothing out the parts of the tables you haven't driven in yet. Don't know if my warmup or transient settings would help (I use GM stepper IAC). Getting the fuel map right is easy. It's the transient settings that take a lot of trial and error.

Do you have the auto-tuning software? I had to pay for TunerStudio (http://www.tunerstudio.com/index.php/tuner-studio/tunerstudioms-menu), but it makes things much faster. Maybe by now there are other packages that do it. Do you have a WBO2?

For a while I had an HEI distributor (locked out) and found it finicky to set up right so that higher advance levels didn't put the rotor out past the edge of the cap contact. It would go to like 2200 RPM and then just sputter out. Not from the RPM, but from the higher advance.

IIRC, # of cylinders is not # of injectors. You should be telling it both of those numbers.
 
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Team208Motorsports said:
4 injectors or 2?
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2 injectors.

Blue85 said:
I've been running Megasquirt on my K5 for a lot of years. Let me know if any of my tables would be helpful. VE should be similar even with TB vs MP, not close enough to run right, but maybe for sanity checks or smoothing out the parts of the tables you haven't driven in yet. Don't know if my warmup or transient settings would help (I use GM stepper IAC). Getting the fuel map right is easy. It's the transient settings that take a lot of trial and error.

Do you have the auto-tuning software? I had to pay for TunerStudio (http://www.tunerstudio.com/index.php/tuner-studio/tunerstudioms-menu), but it makes things much faster. Maybe by now there are other packages that do it. Do you have a WBO2?

For a while I had an HEI distributor (locked out) and found it finicky to set up right so that higher advance levels didn't put the rotor out past the edge of the cap contact. It would go to like 2200 RPM and then just sputter out. Not from the RPM, but from the higher advance.

IIRC, # of cylinders is not # of injectors. You should be telling it both of those numbers.
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If you wouldn't mind sharing that, I won't turn the info down. I do have the pro version of tunerstudio with the autotune, it definitely makes tuning a bit easier...

I wonder if the issue you're describing is what I'm coming across... There's not any way to phase the rotation of the rotor with the variable reluctor below it, is there?

I currently have the distributor set to 8° when the bypass is unplugged, and my offset is somewhere in the 60's if I remember right...
 
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secutright said:
the engine wouldn't rev above 2080 rpm. The second it would go above that the engine would totally cut out and flutter a bit until it recovered into a normal idle.
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The simple test to know if you're running past the dizzy contacts is to dial back the timing and see if the rev limit moves higher.

Did you use a timing light to match up what the ECU thinks timing is to what it really is? Having to run pig rich seems odd. IME a SBC does like a fat idle (13.5-14), but if it doesn't run smooth at stoich off-idle and so on, something is wrong. In fact, it should idle at 14.7, it just won't be as smooth. Either it's misfiring, the timing isn't what you think it is, there's an exhaust leak, etc. Also keep in mind that you're smarter than the WBO2 and there's times you shouldn't listen to it. Misfires or an exhaust leak can make it read incorrectly.

Are you driving the HEI module input or driving the coil directly?
 
What you guys are describing is incorrect timing latency. You need to command a static timing, rev the engine while watching the timing and adjust the latency as needed. Anything that is spinning with fewer teeth usually has this issue.
 
We did use a timing light to get the reading but as scott said the indicator is likely off some, That is simple enough to fix and the values will have to be adjusted on the table but st this point it's just a mismatch in relation to what the base timing is, the total amount it will tolerate won't change from now to if we adjust the offset to show the correct number of degrees..

Also I'd classify 10-11:1 as pig rich and 14:7 as perfect.
This is still a wet manifold with a cam that has 20somthing degrees of overlap so it will require a richer 13s for an idle mixture.. I'd be shocked if it actually would idle at 14:7.. just my opinion..
we have tuned it to be close at this point and have driven it one time so these results are pure 1st draft.. I think it's pretty dang good so far and can only get better.

Blue85 said:
The simple test to know if you're running past the dizzy contacts is to dial back the timing and see if the rev limit moves higher.

Did you use a timing light to match up what the ECU thinks timing is to what it really is? Having to run pig rich seems odd. IME a SBC does like a fat idle (13.5-14), but if it doesn't run smooth at stoich off-idle and so on, something is wrong. In fact, it should idle at 14.7, it just won't be as smooth. Either it's misfiring, the timing isn't what you think it is, there's an exhaust leak, etc. Also keep in mind that you're smarter than the WBO2 and there's times you shouldn't listen to it. Misfires or an exhaust leak can make it read incorrectly.

Are you driving the HEI module input or driving the coil directly?
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This Rev limit was caused by a firmware issue, we reflashed the ecu and it's good now. No issues at all.
 
No but if you do not know true timing and your latency is off then how do you know how much timing it will take or how much timing there actually is? LOL. You've come to far for "good enough"
 
Team208Motorsports said:
No but if you do not know true timing and your latency is off then how do you know how much timing it will take or how much timing there actually is? LOL. You've come to far for "good enough"
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I totally agree but we had no idea it was an issue until we realized the offset wasn't right, obviously we'll fix it before we mess with it anymore. And ya good enough isn't gonna fly here!
 
Team208Motorsports said:
No but if you do not know true timing and your latency is off then how do you know how much timing it will take or how much timing there actually is? LOL. You've come to far for "good enough"
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I do agree with that. I think I'm gonna have to order an adjustable timing pointer or something. The one that came with my timing cover is for another size balancer than what I have, sits a good inch away from it. Once I get that, I'll set the engine to tdc with the pencil in cylinder 1 and set the pointer, then reset the timing offset to match. Running it like this was just kind of a stop gap until I get the correct pointer.

As far as the mixture, I was also thinking it would run a little happier being rich at idle because of the bigger cam, but I could definitely be wrong also.
 
I've never messed with Mega Squirt stuff but heres some perspective on my FAST system: I have to set the idle to about 13.0:1. The idle is the smoothest there and doesn't drop or stumble when you put a load on the engine like turning the wheel while parked, however the exhaust smells pretty bad but that's where the engine is happiest so I have to live with it.
 
I personally don't feel the ecu matters, the type of injection port vs tb matters and the intake and cam combo play a bigger part in what the engine will tolerate at idle, if you have a wet manifold and lots of overlap you likely would have some reversion which pushes some of that fuel and air mixture back up and out the throttle bore, this is evident it you were to look at the carb at idle you could almost see the cloud above the engine, if you watch some you tube video of engine dyno's you can see some of them doing this.
Efi is great at making a big cam sound smaller because the events are timed so the issue with reversion is less of an issue because there is some control vs a carb where you basically "flood" the intake with enough fuel to satisfy the engine, it's pulling in what it needs because of vacuum and the venturies discharge the fuel and shear it but it is still more fuel than it might use. So that fuel that isn't burned wets the floor and walls of the intake and is consumed when the load or rpm changes.. this is sometimes where dieseling or run on come from in carbed motors.
Small cammed engines have little or no overlap and most efi stuff likes a wide lobe separation like 112+ most oem are using 114 and up so the cam events are timed so the intake and exhaust events are far enough apart to give exhaust scavenging a chance to help pull the intake charge into the cylinder vs using intake overlap to stuff the cylinder with fuel and air..
The short story is radical cams require more fuel regardless than an engine that is closer to stock or less cammy..
This is my opinion only and observations of what I've seen it's not gospel or fact..
 
Team208Motorsports said:
We'll go over all that. I'll publicly walk you guys through the tune if you like.
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If you're up for it, I'd love to have that. It would be dumb of me to not take a professional's guidance on this, and it would be good for general knowledge too for anyone else following my path down the line. So far I know I need to get a new timing pointer and dial it in to check my offset for what it really is. What's your thought on my injector sizing?

Just so you know too, right now I'm running without any accel enrichment or overrun cut, wanted to get the base ve table kinda close without having too many variables involved. Where I'm having an issue with leaning out is in the high kpa and low RPM corner, I'm not mashing the throttle, kinda easing in to it, but could lack of AE be causing that?

I'll post my tune up when I get to my computer.
 
Team208Motorsports said:
You need AE. You only want to make VE corrections with stable fueling anyway..... Need AE though.
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Ok, I'll mess with that. I got a timing pointer ordered that should match my balancer better, should be here Friday. Out of curiosity, any suggestions for staying AE values?
 
Ok, so I've been asked to provide part numbers for the various adapter fittings I used throughout my fuel system by people who are looking to do a TBI swap such as mine. I like AN fittings, it's nice to have standard hoses that, one adapters are installed, don't require me to remember all kinds of random fitting size. So, here's the list of adapters used on my own build.

Starting at the fuel tank, to adapt the OEM metric fuel pump fittings to -6AN:

Russell 640820 - M14 x 1.5 O-Ring to -6
Russell 640830 - M16 x 1.5 O-Ring to -6


Then I used some compression style fittings to adapt my stock fuel lines to AN, they work pretty good. Obviously a flare with the nuts would be a better connection to use here, but I did this with the lines still in the truck, and couldn't get my flaring tool into the locations where the ends of the lines are. Note that these are only recommended for use on aluminum tubing. I have had success using them on steel tubing, but your mileage may vary...

Earl's 165056ERL - 5/16 to -6, qty 2
Earl's 165006ERL - 3/8 to -6, qty 2

Then for the hard ones to find. These screw directly into the TBI regulator body, and stub out -6AN. These come with the necessary Teflon O-Rings to seal into the TBI.

Russell 640803 - M12 x 1.25 O-Ring to -6
Russell 640813 - M14 x 1.25 O-Ring to -6


Beyond that I got an assortment of -6 hose ends, including Straight, 45°, and 90°, and I believe about 25' of -6 braided hose. If there's any other questions, let me know, I'll try to get the information posted up to accompany this.
 
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