5.3 compared to 5.7

[RED TAHOE LS]

Just curious how you think the two engines compare. My Tahoe 5.7 Vortec is as strong as it was when new. I've played with few 5.3's while entering freeway and notice one close to my rear bumper, so I just ease into it and have yet found one that compares to the torque. Just curious.
David g...........

 

[iamdub]

More power per cube, lighter, smoother, less potential for leaks, more efficient, stronger architecture. The Gen3 5.3 has 30-55 more HP but about 20 lb-ft less TQ. I'm sure the loss in TQ is from the smaller displacement and cam chosen to help with fuel economy which resulted in higher HP.

Punch the 5.3 out to a 5.7 and run the same sized cam as the Gen2 5.7 and the Gen3 would beat it in numbers as well as all the other attributes.

 

[swathdiver]

Just curious how you think the two engines compare.

Help revive my memory David, what's the horsepower and torque ratings of the motor and how much does your truck weigh?

My LC9 is rated at 310 HP @ 5200 RPMs and 335 FT/LBS Torque @ 4400 RPMs. It's detuned some compared with Chris' Tahoe for example which if memory serves makes 320 @ 5200 and 340 Torque @ 4200 that year. When the 5.3s got VVT the peak torque came in at 4000 RPMs and 5 FT/LBS less and HP peaked at 5400 RPMs. Them new Gen V L83s make over 350 horses.

 

[RED TAHOE LS]

James, thanks for the reply, never having put my Tahoe on scales, I'm thinking probably in the 5000 # range. I'm not a numbers guy, just recognize power easily, and since it has 3.73 gears, the 255 hp makes for a lot of zip with a good trans.
Rated hp was flopped around by mfg's like a yo yo in the late 60's/70's to help sell muscle car's so that the average guy could get affordable insurance. Since being a gm guy for a long time, everyone remembers the Z/28 camaro's from 67-69, they were rated @ 290 hp which was a joke.
Having campaigned a 1970 SS/DA Hemi Cuda in NHRA Division 2 , I know what performance feels like.
I was just getting pros/cons of the comparison.
David g.........

 

[swathdiver]

My calculated RWHP through the traps is 302 horsepower. That's with one bad cat and a BlackBear tune. Your SBC of course generally makes way more torque than horsepower and were low-revving engines compared with the LS. Actually, I don't know what engine you have, what is it?

 

[iamdub]

My calculated RWHP through the traps is 302 horsepower. That's with one bad cat and a BlackBear tune. Your SBC of course generally makes way more torque than horsepower and were low-revving engines compared with the LS. Actually, I don't know what engine you have, what is it?

Likely the L31.

 

[RED TAHOE LS]

Just thought it was a simple question, rest my case.

 

[swathdiver]

I looked up your L31, thanks Chris, and that is a great engine. Nice flat torque curve and you and I know torque is what get them moving and the more down low the better.

 

[rockola1971]

I own (2) 5.3L (In 03 Tahoes) (Not including the one sitting on my engine stand and one sitting on a pallet) and I own a 5.7L equipped Z71 Sierra (Vin R) and I can tell you hands down the 5.7L equipped Sierra pulls my 5400lb 32ft camper better. My 5.3L Tahoes do ok but the 5.7L just has the torque and in the right place to get the weight moving.

 

[swathdiver]

...the 5.7L just has the torque and in the right place to get the weight moving.

Down low! This is why GM went with the 6-speeds to get the 5.3 trucks moving; first gear final drive is 13.77:1!