tuning Haltech on a performance car for FE
This is an experiment of sorts. I've recently purchased a "sleeper" of a performance car. It's got plenty of power with a VERY easy potential for consideral more power, but with gas prices as high as they are, I can't drive the car every day while getting 20 mpg. So, I want my cake, and I want to eat it.
The car in question is a 1991 Chevy Cavalier station wagon. Under the hood is a fully built 3.1L cammed and turboed V6. The 2 good things about the car for FE are the 5 speed manual transmission swap the last owner did and the Haltech standalone fully programable ECU.
As it sits right now, the car will/has run a high 13 second 1/4 mile at 105 mph. The last owner told me that it got 20 mpg on a regular bassis, on the highway. That's not acceptable to me.
My goals are to be able to carry my wife and 2 kids anywhere in comfort along with any luggage we have while getting a minimum of 25 mpg city/35 mpg highway AND be able to run a 13 second 1/4 mile.
I've owned the car for just 2 weeks and I'm already learning a great deal about the Haltech and how to tune it for fuel mileage. Here's some things that I tuned......
1. I lowered the idle from 1200 rpm to 800 rpm and it doesn't hunt for an idle anymore
2. I turned closed loop operation on! (I can't believe it was turned off!!)
3. I solved the overheating issue (stuck thermostat wouldn't open till 210 degrees, I replaced it with a 160 degree thermostat)
4. I turned the accelerator pump program down slightly
I've not goen through a full tank of gas yet with these changes, but I can already tell a VERY good improvement in gas mileage!
So, does anyone have any experiance with tuning a Haltech computer? I'll be borrowing a wideband air/fuel meter to help fine tune the air/fuel maps in the next couple of weeks, but that brings up a question. I can run a wide band O2 sensor connected to the Haltech and I can tell the Haltech what O2 sensor voltage to shoot for. So it will effectively adjust the air/fuel mix automatically. However it can only adjust the air/fuel mix up or down 20%. What should I do? Find the money to get a wideband O2 and wire it in, or spend a few days tuning the air/fuel maps with the wideband air/fuel meter?
Once I get the car running where I want it to, I'll be working on aero mods!!
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