1991 GMC Syclone - Elite 2500

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Joined: Tue Oct 25, 2016 7:30 am
Location: Pittsburgh, USA

1991 GMC Syclone - Elite 2500

Postby Aeroking » Fri Nov 11, 2016 6:05 am

I have converted my vehicle from a FAST ECU to a Haltech Elite 2500. My fun car is a 1991 GMC Syclone truck. I purchased the truck stock in 2006, and I have upgraded everything on the truck myself. I was running a FAST ECU from the late 90s with a universal harness. The Fast ECU was very basic, and had no expansion capabilities, no safeguards, and no advanced features.

Factory Specs:
    • 4.3L V6 All-Wheel Drive GM compact-size truck
    • Mitsubishi TD06 turbo and Garrett Water intercooler
    • 4 speed mechanical automatic transmission
    • Distributor ignition with ECU spark advance
    • 6 injector batch-fire fuel injection
    • MAP based VE

My modifications:
    • forged Pistons & Con Rods
    • forged custom crankshaft
    • custom spec camshaft
    • aftermarket aluminum heads
    • fabricated intake manifold
    • 1300cfm throttle body
    • Precision 6766 turbo, stainless headers & aluminum exhaust
    • Spearco Air intercooler
    • Tial 38mm wastegate
    • SMP 1200cc injectors & Magnafuel 4303 pump
    • LS3 (D510C) ignition coil packs (direct fire)
    • custom built race-prepped automatic transmission & custom billet torque converter
    • chromoly rollcage with 5-point harnesses
    • upgrade disc brakes front & rear, with 17”x9.5” wheels
    • converted front to coilovers, with upgraded swaybars, rear leaf springs with traction bars
    • Elite 2500 & Premium harness
    • EFI Connection retrofit crank & cam position sensors (60-2 & 1x)
    • GaugeArt LCD dash gauges
    • PWM controlled fuel pump & thermofan
    • and a slew of smaller upgrades to the engine, fuel system, cooling system, suspension and brakes.

Prior I was plagued with ignition problems on this truck. When using the factory style ignition I would blowout the spark at low boost. Upgrading the ignition components proved to be move problematic. The MSD ignition parts were way to powerful when mixed with stock components. I had to switch to a matched ignition system. This allowed me to run the boost I wanted, but at the sacrifice of parts wear. The MSD parts literally ate themselves. I replace the distributor cap, and spark plug leads every 500 miles. If I try to run them longer I melt the caps, and deteriorate the plug leads. The ignition is too powerful. My goal with the Haltech is to have a direct-fire system using standard duty coilpacks, and do away with the racing ignition system. Also I would like to wire the injectors for sequential control.

I rarely drive the truck. It is a weekend fun car, and I go to the dragstrip 2 or 3 times each year. Due to ignition problems, and traction problems the results of my setup are less than ideal. My best track time is a 11.0 but with a speed of 109mph. My best top speed was 123mph, but the lap time was 12.4 seconds. All of these were at 19-20psi of boost, so if I got my issues fixed the truck should be really impressive. However, I primarily use the truck for the street, and it is a blast to drive. No track results yet with the Elite.

My requirements for the Elite include:
    • Direct-fire ignition for 6 LS3 coilpacks
    • Full-Sequential fuel injection
    • Closed Loop wideband
    • Closed Loop boost control
    • FlexFuel
    • Knock control
    • Front & Rear wheel slip traction control
    • Inputs for Fuel Pressure, Oil Pressure, Speed Sensor, Fuel Level, Trans Temp
    • Outputs for Fuel Pump, Idle stepper motor, Radiator fan, Intercooler fan, Torque converter lockup,

A couple pictures:


I will post again when i get some results. Thank you
1991 GMC Syclone AWD - 4.3L turbo V6, 528awhp @ 19psi
- Elite 2500, CnP, Boost, Knock, IAC, FlexFuel, WBO2

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