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Old 12-27-2009, 07:36 PM   #34
Mark42
 
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Well the gears and Truetrac have been in for a few days, and the car has been driven nice and easy for 150 miles. So I thought its time for an update.

The gears make a slight noise that has diminished some since being installed, and if the gears don't quiet down any more, then I figure a layer of Dynomat over the rear axle hump might help deaden the residual noise. The last few days of driving before having the gears installed the rear seat was in the down position so the rear end could be heard better. I noticed that the factory gears make ever so slight wind noise at 50 mph and higher. Nothing you would notice unless you really listened for it. By comparison, the new Summit 3.73 gears make a distinct "white noise" sound when feathering the throttle and at steady cruise, but no noise accelerating or coasting down.

Yesterday I got to drive the car in the rain. Was pleased to feel the Truetrac doing what it is supposed to. Pulling out of a parking lot into 50 mph traffic would have been a real problem with the previous open rear, spinning one tire and not picking up speed. Now with the Truetrac, the car is much more sure footed, and it scoots right into traffic and accelerates with no wheel spin. Around the roads near my house the tires didn't spin at the usual places; inclined intersections, right hand turns uphill from stop sign, etc. But if too much throttle is applied, the car does what is expected in the wet... locks up the Truetrac and spin both tires.

Today the sun came out and I got to drive on dry pavement. Decided to be a little more aggressive with the throttle. I was surprised to feel both tires break loose on dry pavement with only modest throttle input. I guess 3.73 is really multiplying the torque compared to the old 3.08's.

So its still being driven mildly, no more than half or 3/4 throttle and then only for a short bursts.

Still need to have the PCM updated for the speedo. While that is being done, I figure the fan temps should be lowered to match the new 180* thermostat on order, ( Low Speed On/Off: 194/185 °F - High Speed On/Off: 204/195°F ), and remove the high speed limiter.

A real noticeable change is how quickly the car accelerates even under modest throttle. And long inclines don't feel like the car is straining to get up and lugging the motor. Car is much more responsive to even modest increase in throttle.

I can hardly wait until 500 miles rolls around!!!
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1998 Firebird Coupe
Mods: 3.73 Gears, Eaton TrueTrac, PCM Tune, LS1 Aluminum Drive Shaft, Cold Air Intake, 180 Thermostat, Magnaflow Cat-Back Exhaust, Moog LCA busings.

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