Megasquirting a 383 SBC

Recently I have been setting up and learning a lot about the Megasquirt EFI system which I plan on using to run the engine in my brothers 1989 Firebird. We (my brother and I) decided to go with this system due to its affordability and how its designed to work with GM sensors. It also has the option to connect to the factory harness making installation much easier. This is also my first foray in tuning an EFI system.

I’ve never been much of an engine guy. I know what makes them tick and the theories behind how a lot of things in the engine work, but I never cared much about engine building or lusted after tons of horsepower. Road racing doesn’t have to be about big horse power numbers, and generally, if you road race with a lot of power, it makes everything more expensive. Having a reliable engine is what I feel is the most important thing, and its hard to get more reliable than a stock engine.

I noticed early on that we have a surplus of engine people here in America. Lets face it, this is the land of drag racing and we have people that push just about every engine to the limits of its block. What we don’t seem to have are people that know how to make a car handle, so that’s the direction I went. But the great thing about all these drag racers is that we have a wealth of engine knowledge at our finger tips. They give us great parts warehouses like Summit Racing and they also give us local engine shops where you can order anything you ever wanted… for a price.

After we blew the Firebird’s engine in the banked turns of the Milwaukee Mile race course (those extended turns in the oval parts of the course caused the oil to go to one side of the engine, running the sump dry), we contacted a local engine builder for a 383 short block. My brother has some experience building engines since he modified the 350 that was in the Firebird some time ago. Since we had those parts, we would just complete the short block ourselves. This time around, we decided to go with a stand alone EFI system since the old configuration was never tuned well.

At this point,¬† the Megasquirt and the engine are not totally completed so I haven’t run anything as of yet; so mostly I have been doing research on what it takes to get the engine running with this thing. At first I was quite frustrated; I loaded up the tuning software and looked over the settings. None of the settings them had any values. I then went looking for some sort of base line to start off of – a starting point for my hardware. With the Megasquirt being known as the DIY system, you would think that there would be an extensive library of maps and settings for you to pick and chose from. Unfortunately, this isn’t the case. There is a lot of information out there, but all of it is very general. For instance, Injector open time – which is explained as how long it takes the fuel injector¬†solenoid to open the injector after its been energized- is easy to understand. But, knowing this information doesn’t help you in setting a value for your injectors. I then learned that the firmware for the Megasquirt comes preloaded with base settings. So all my frustration was unfounded! Of course, there are nuances to everyone’s engine, so you will have to find information on those specific things – Mine was the old GM HEI ignition which requires soldering jumpers in the Megasquirt and special settings ignition settings. Though, with a chevy small block which has been megasquirted countless times, this information was published on their site. If your going to Megasquirt somthing more exotic, this can be tricky.

Right now, we are waiting on a few things for the engine before we can proceed any further. I will update as we make progress.

Here’s the specs of the engine:
383 sbc
AFR 190cc heads (no longer in production)
10.x:1 Compression
Comp cams hydraulic roller cam: .576 lift (gross). 230 intake, 236 exhaust @.050
LT-1 intake modified for gen 1 SBC
TPI throttle body
24# svo injectors which are too small for this engine. I’ll have to upgrade those later.
Short tube headers. That’s all that fits on a 3rd gen f-body.

We are hoping for at least 450hp at the fly.

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