5.3 trailblazer vs 5.3 silverado

[atv hauler]

Does anyone know for sure why the LH6 engine in these 2 vehicles have different outputs? exhaust system???, ecm set up??? any ideas?
2006 Trailblazer 5.3 2007/2008 Silverado 5.3
300hp@5200rpm 315hp@5200rpm
330lb.-ft.@4000rpm 338lb.-ft.@4400rpm

keep in mind the LH6 is a 5.3L V8 with active fuel management.

[ShadowClutch]

Some years have diff ratings, Maybe there is a difference between the 06 LH6 and the 08 LH6. Compare them year to year to find out. Just my guess.

[bartonmd]

The '03 5.3L Trailblazer is rated at 303hp... Still not 315... I suspect exhaust and ECM differences...

Mike

[DZP]

Vehicle weight can play a role as well as gearing and many more variables.

[atv hauler]

The '03 5.3L Trailblazer is rated at 303hp... Still not 315... I suspect exhaust and ECM differences...

Mike

03 5.3 trailblazer is NOT a LH6 engine
The 315hp rating is for the 07/08 silverado.

[hailtoby]

I think that the car manufacturers have some room to play with the numbers. Im willing to bet that they are closer to the same, but they say the silverado has more output just for marketability.

[bartonmd]

03 5.3 trailblazer is NOT a LH6 engine
The 315hp rating is for the 07/08 silverado.

Sorry, that was a typo... The 3 is right below the 6... and the '06/07 Trailblazer is rated at 303hp (at least the '07 is)...

I suspect it has something to do with us having a "Y" pipe in the exhaust, and the trucks having duals back into one muffler, then coming out as one pipe. (at least that's the way the trucks used to be)

BTW, I suspect the trucks have less torque management than the SUV's... My dad's 2000 5.3L silverado (285 horse), will EASILY outpull my buddy's 5.3L Avalanche, because the AV, being on the Suburban chassis, has the SUV programming with more torque management... He said his '97 Z71 350 actually pulled better than this AV does, and my dad's 2000 5.3L truck is WORLDS better at towing than my buddy's '97 350 was... (I realize the AV weighs more, but not THAT much more, for how it feels towing)

Mike

[SandCountry]

Sorry to go :offtopic: but I feel some clarification is needed!

I would guess that the Silverado probably had a shorter final drive than the Avalanche- I would bet that a lot more Avalanches came with the tallest gear available, where a good number of pickup truck buyers get shorter ones for more serious towing/off-roading. Also, don't discount the weight of the Avalanche as a factor. IIRC, an Avalanche actually weighs more than a Suburban due to added structural stiffening (not to mention the extra cladding! :dielaugh:). No Silverado, short of a 3/4 ton, weighs what a Suburban weighs. And since I don't think the HD crew cab 1500 came out until 2001, yours is probably extended cab. Even lighter. And if one's 4wd and one isn't, all bets are off. Ever driven a 2wd TB and a 4wd TB? If not, you'd be amazed at how much slower the 4wd feels. Even with the same rear end (I checked). These things aren't Accords, you can't just make sweeping generalizations about performance. Different equipment makes a big difference in feel.


Oh, and it doesn't make sense that GM would put more torque management on SUV's than on Pickups. The want the vehicles to be as fast as possible. They only limit them due to driveline life requirements. If they both have the same driveline, wouldn't they be "managed" in similar fashions? But, this wouldn't be the first time GM's done something stupid like that...

Back on topic- the Impala SS also makes 303 hp. And marketing definitely plays a big role. I want to say that dyno tests showed that the last-gen Camaro SS & Trans Am actually made the same HP/Torque as the base Corvette- not 325hp as advertised, but the same 350hp as the C5. But we couldn't have the little brother sneaking up on the Corvette, could we? :hahano: Same deal with the Mercedes AMG 55's. The S55 was rated at 493hp, but the E55 was kept down to "only" 469. Mercedes claimed exhaust tuning differences. However, as before, dyno tests revealed otherwise.

[bartonmd]

Sorry to go :offtopic: but I feel some clarification is needed!

I would guess that the Silverado probably had a shorter final drive than the Avalanche- I would bet that a lot more Avalanches came with the tallest gear available, where a good number of pickup truck buyers get shorter ones for more serious towing/off-roading. Also, don't discount the weight of the Avalanche as a factor. IIRC, an Avalanche actually weighs more than a Suburban due to added structural stiffening (not to mention the extra cladding! :dielaugh:). No Silverado, short of a 3/4 ton, weighs what a Suburban weighs. And since I don't think the HD crew cab 1500 came out until 2001, yours is probably extended cab. Even lighter. And if one's 4wd and one isn't, all bets are off. Ever driven a 2wd TB and a 4wd TB? If not, you'd be amazed at how much slower the 4wd feels. Even with the same rear end (I checked). These things aren't Accords, you can't just make sweeping generalizations about performance. Different equipment makes a big difference in feel.

All (3) vehicles are 3.73 final drive, all 4WD, and the trucks were extended cab. The AV does weigh 350-400# more than the truck, but they would feel about the same when the AV was pulling a 4000# trailer, and the silverado was pulling a 5500# trailer... At least in the first 2 gears, then they felt closer to the same.


Oh, and it doesn't make sense that GM would put more torque management on SUV's than on Pickups. The want the vehicles to be as fast as possible. They only limit them due to driveline life requirements. If they both have the same driveline, wouldn't they be "managed" in similar fashions? But, this wouldn't be the first time GM's done something stupid like that...

Ah, but it does make sense... I suspect they tq limit the SUV's they way they "want to" for drivetrain life, but because competition between the trucks of different brands is so close, I suspect they sacrifice some drivetrain life for drivability and tow rating, and so they perform more favorably up against the competition. Actually, the friend with the AV traded it in on a 4-door pickup (the first year of them... '04 maybe?), and is VERY happy with the performance... same gears, 4WD, everything... We haven't lined them up or anything, but I have the 5.3 in my SWB TB, and I'll tell you that have driven both of them, his truck (that weighs 600# more than the TB, BTW) feels as strong in the first 2 gears as the TB... except the acceleration of the truck slows down in third and 4th like you'd expect, but the TB just keeps trucking like... well... like it weighs 600# less...

Back on topic- the Impala SS also makes 303 hp. And marketing definitely plays a big role. I want to say that dyno tests showed that the last-gen Camaro SS & Trans Am actually made the same HP/Torque as the base Corvette- not 325hp as advertised, but the same 350hp as the C5. But we couldn't have the little brother sneaking up on the Corvette, could we? :hahano: Same deal with the Mercedes AMG 55's. The S55 was rated at 493hp, but the E55 was kept down to "only" 469. Mercedes claimed exhaust tuning differences. However, as before, dyno tests revealed otherwise.

I do agree, but I suspect our Y-pipe doesn't help our cause compared to the way they come together in the muffler in the trucks (or at least the way they used to do it a few years ago)...

Mike

[Nukedog]

It's 15 crankhp difference and the trucks also have electric fans (my 5.3 Sivys did) and that is usually good for....15 crank hp...:thumbsup: