lg4 vs lb9
12-05-2012, 01:45 PM
#1
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Car: 2012 Ram express
Engine: 5.7 hemi
Transmission: auto
Axle/Gears: 3.55
lg4 vs lb9
why does the 87 lg4 have 20 less hp then the 87 lb9 automatic? Same heads and cam. Does the tpi induction give the 305 20hp over the qjet?
12-05-2012, 04:47 PM
#3
Re: lg4 vs lb9
The LG4's got different heads, cams, and exhaust compaired to the LB9 cars.
Look up specs on the L69 and compare them to the LG4. The L69 high output 305 motor is a factory hot rodded LG4. Bigger exhaust, higher lift cam, better breathing intake, and steeper gears.
The LG4 and L69 motors had the same heads but different pistons - flat for the L69 and dished for the LG4. That is also part of the performance equation to because the L69 had a 9.5:1 compression ratio and the LG4 had 8.6:1 compression ratio.
The L69 was the basis for the LB9 that came along later. The LG4 would perform a lot better if just a L69 style intake and L69/LB9/L98 factory style exhaust system was installed on a 100% stock motor.
Look up specs on the L69 and compare them to the LG4. The L69 high output 305 motor is a factory hot rodded LG4. Bigger exhaust, higher lift cam, better breathing intake, and steeper gears.
The LG4 and L69 motors had the same heads but different pistons - flat for the L69 and dished for the LG4. That is also part of the performance equation to because the L69 had a 9.5:1 compression ratio and the LG4 had 8.6:1 compression ratio.
The L69 was the basis for the LB9 that came along later. The LG4 would perform a lot better if just a L69 style intake and L69/LB9/L98 factory style exhaust system was installed on a 100% stock motor.
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