Dyno Testing 7 Popular LT1 Engine Modifications

Fact Or Fiction - Part 1

Eric McClellan Apr 9, 2013 0 Comment(s)
Ghtp 1304 01 Dyno Testing 7 Popular Lt1 Engine Modifications 1/23

Ok fine, you got us. We have a thing for the LT series of motors, we just do. Sure, the trend is shying away from the LT1 right now for the more popular LS series of engines, but for a good number of you out there, the LT1 is in your ride right now. We are here to put some of the popular simple bolt-ons on the dyno and show once and for all what's worth what in terms of your dollar. We set out on a field trip to TPIS in Chaska, Minnesota, home to a group of LT1 gurus who've been racing the plucky little engine since its inception. TPIS put together a test mule and operated the dyno while we made changes and recorded the results.

Test 1 – Baseline Stock Engine
Max Power: 367tq, 316hp
Average Power: 330tq, 264hp

First, let's go over what our test motor is and get that out of the way. The motor is a .040-inch over-bored LT1 block with a lot of the standard stock parts such as the crank, heads, cast exhaust manifolds, intake, 1.5-ratio rockers, oil pan, 48mm throttle body, stock 24-pound injectors and stock (43psi) fuel pressure. Coolant temps were a constant 175-180 degrees throughout our testing and oil temp stayed right at 180-190 degrees. For reliability reasons several aftermarket parts were added including Scat rods (stock length), Speedpro hypereutectic flat top pistons (with valve reliefs), and the block was zero decked with a 10.5:1 compression. Fuel was your standard 91-octane from the local Gas-n-Blow gas station.

Our motor was broken in with the standard methods and then given 20 solid pulls to first make sure the motor was ready for our tests, and secondly to create a baseline. Our baseline pulls netted us a healthy 316 horsepower and 367 lbs-ft of torque completely naked, no accessories or cats. The following tests were progressive, which means that each item was added in order and left on the motor to see the cumulative effect of each part. Each part was given three pulls on the dyno to ensure that it didn't get a bum pull and we could be as accurate as possible.

Ghtp 1304 05 Dyno Testing 7 Popular Lt1 Engine Modifications Stock Dyno Run Chart 5/23


Test 2 – Plugs and Wires
Max Power: 365tq, 320hp
Average Power: 332tq, 266hp
Cost: $85

Ghtp 1304 09 Dyno Testing 7 Popular Lt1 Engine Modifications Spark 6/23

We replaced the stock plugs and wires with a set of Bosch Platinum plugs and a set of TPIS proprietary wires. Most stock engines come with a pretty flimsy set of wires; sure they get the job done, but they don't allow for a greater spark. Upgrading the wires to a thicker, spiral bound core will improve spark plug discharge, thus creating a stronger ignition source and in theory, more power. Our plugs were gapped to 0.050-inch with a stock heat range, but the upgraded platinum plug has greater efficiency. While we may have lost a bit of max torque, we did make slight gains in our average power numbers. Sure, the power per dollar cost here may not seem worth it, but if you plan on bigger upgrades in the future, these are a must.

Ghtp 1304 07 Dyno Testing 7 Popular Lt1 Engine Modifications Plugs And Wires Dyno Chart 7/23

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