Displacement On Demand: Part III, Tuning Golen’s 383 LT1 For 435 Horses

Displacement On Demand
Part III: Tuning Golen's 383 LT1 For 435 Horses (Continued)

Deavtivating sensors

C.A.T.S. allows the user to observe virtually everything that is going on inside the engine as it is happening. You can see on the top screen that four degrees of timing was being pulled, which was attributed to the engine stand creating vibrations that falsely set off the knock sensors. To remedy this Matt deactivated them and also pulled several other sensors like those that interact with the air- conditioner and speedometer while he was at it.

Making changes with C.A.T.S.

Even with those changes, however, something was not right. Not only was the engine not making the power it should, but also it didn't have that WOT scream. Instead it sounded lackadaisical, lethargic and just plain lazy.






	Not knowing what could be causing the aforementioned laziness, attention was turned to the air/fuel ratio, which was at a rich 10 to 1. Injector pulse width was trimmed 3 percent, then 10 percent, to try and lean out the mixture. However, only a slight improvement resulted, generating 409 hp and 421 lb-ft (corrected).

Optispark failure At last it seems we had found the culprit of our misadventures. The dyno session was abruptly interrupted when the rotor blew apart, as you can see in the picture; the metal tip in Dan's hand was originally connected to the white plastic base. This is a common problem with the Optispark and can even happen on practically brand new units such as this one. While Dan was rebuilding the distributor, owner Chad Golen put in a call to Bryan Herter with the current data. Bryan then sent over a new program, which, when combined with a fresh distributor, seemed to do the trick.

The horsepower got up to 448.5; and environmental corrections pegged customer Val Becker's 383 at 435 hp and 447lb-ft of torque. It's alive! The (uncorrected) horsepower got up to 448.5; and environmental corrections pegged customer Val Becker's 383 at 435 hp and 447lb-ft of torque. It seems the extra port work may have robbed a little torque, as the base 383 package usually makes around 464. However, it seems well worth it for the 35 extra horsepower, which now peaks at 5800 rpm as opposed to 5000 rpm.

These boneyard treasures are quite common as the police and some taxis used LT1s in their Caprices.

These boneyard treasures are quite common as the police and some taxis used LT1s in their Caprices.
Hard to believe this rusty rat's nest could be the heart of your new 400-plus horsepower hot rod after only a few weeks at Golen.

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This article was originally published in the April 2005 issue of GM High Tech Performance and is copyrighted by Primedia Inc., All Rights Reserved.
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