Dominic Sorresso

Part throttle tune is even more critical in EFI ECM comtrolled motors because it establishes the baseline for all other fueling. And yeah I tuned carbs way back when which actually helps in understanding what you are doing w EFI.
I can text u my # to discuss remote tuning. Easier to
review the process that way.

Rkreigh

amen! I'm really interested right now in the megasquirt approach to tuning an lt5

the factory ecm is quite capable, but the new stuff is easier and more fun and I've been wanting to get into a megasquirt so what better project than to do an lt5. My buddy Dr. Phil has one, I'm going to get my grubby little hands on it !!

I think we can use possibly the saturn coil on plug setup, and fire both injectors except at idle (I have no secondaries).

no doubt the megasquirt offers some very nice capabilities!

Dominic Sorresso

Ron,

Unless you are running something exotic for the motor and don't care about comms w the CCM, I don't see that the MS unit offers any advantage over the stock ECM. Don't think u can find better software for running a motor for day in day out than what GM has done. The aftermarket units are optimized for one or two modes of operation, while the OEM stuff has to deal w all the contingencies required to get EPA certification. I'd love to be able to add some additional or substitute code to the OEM programming to provide additional functionality. Have a look at www.dynamicefi.com for a good example of what can be done w OEM ECMs.

KJL

Now on with port matching heads to gasket and IH's.

KJL

Here are some updated IH post porting numbers.

KJL

Here are the final values. Did not expect much of a change with the secondaries IH ports. I did not record Pre Port data for the intake plenum at -11"wg. The value 1.7" is approximate based on a sampling of the ports. This was done just to get a feel for how well the plenum values matched with the IH. Greater is good!

Dominic Sorresso

Just goes to show how much more the LT5 was capable of.

KJL

The intake horn all ready to go.

Paul Workman

It would be worth knowing what the change in flow is between the stock air horn and one that has been "ported". Same for the stock vs. one with the primary ported to 63mm, and a third scenario, 63mm with the material removed from the air-horn and regions adjacent to the primary ports (to enhance flow).

Can ya fill in any of these blanks?

KJL

Paul-
My guess is there would be a small improvement in flow through the horn at high velocities. I just removed some casting imperfections and some of the sharp edges where the air transitions into the throttle body. My guess is the horn, given its size relative to everything else is not a pinch point for air flow. My little flow bench setup could not flow enough air to register any meaningful values for that.

Dominic Sorresso

If using a 63mm TB, it would be more beneficial to port match the plenum to the TB

Rkreigh

I want to retain the ccm functionality and splice in rather than unplug the factory

I'm looking to turbo and the wideband correction and faster processing, fail safes, ect make the after market stuff attractive. coil on plug, and control over the turbo with one ecm is really what I'm looking for so I can do boost by speed, traction control (that works!) and other new tech that aren't available in the factory ecm

I do agree with you that the factory ecm is great if you can deal with the klunky tuning tools.

the modern interfaces IMHO are easier to use and you can road tune without buying so much stuff.

tuning the low end with the big cams is a hassle too. while I've gotten good streetability, I'm still chasing some low end tip in issues and the factory narrow band o2 stuff really isn't helping me.

for me the logging and road tune of an aftermarket system is a great option.

I'm not ready to go there just yet, but it does look attractive! MS stuff is about 1300 for the ecm and wiring. Now all I need is lots of smarts!!! (oh and cash)

Dominic Sorresso

I would agree w aftermarket only because the OEM system has no support for power adders like NOS, FI, CnP etc. I wish I knew how to program my own routines. There's plenty of stuff that could be removed from the factory code and replaced w custom.
As for the tip in issue, my cams (Pete's Intake and Exhaust) may not be as big as yours, but then I have stock displacement as well. I have no issue whatsoever w tip in. Throttle response is immediate and it beats the ASR activation at times. Idle is between 875-925, no stalling, 30mpg at 70mph cruise. Little rattle from Fidanza at idle and absence of drone at cruise using no resonator. The driveability and streetability is in Closed Loop.
But u do need to know your way around the calibration params beyond just fuel and spark tables.

KJL

Finally putting her back together. Mods include ported intake and injector housings, port matched primary head ports, locked open secondary throttle blades, MH chip to support mods, new Stant thermostat, new serpentine belt, new FIC fuel injectors, new fuel system o-rings and plugged throttle body coolant system.

Dominic Sorresso

Have fun.

KJL

All I need to do is turn the key.....always stressful. Will do today. Is there anything I should do before hand like spray some oil in the cylinders? The car has been sitting since may.

Dominic Sorresso

You can always pull the ignition fuse and just crank the motor to get oil up onto the cams.

KJL

Where is the fuse? I see one for FI1 and FI2 but nothing that specifically says ignition.

Dominic Sorresso

Pull the fuse on INJ 1 (20A). That supplies power to the coil packs.

KJL

Sooooo....it worked, however when I plugged the fuse back in it still would not start. A plug, the one to the left of the the large connector that screws into that module located up under the intake plenum as come lose. Once I get my borescope charged I can get a better look. I am hoping to be able just push it back in. The day I can start a car following an extensive project the first time, I will know hell as truly frozen over.

Update: I forgot to plug the two connectors into the coil packs. That would explain no spark......

Looks like I get to practice removing the plenum again. I will try and access by just removing the map sensor bracket first but I doubt I will be able to get to it from there.