5.3 has more power than GM advertises?

MSPT · October 11, 2016

I was speaking with my local GM expert and he informed me that most of the 2014+ 5.3 trucks he puts on his dyno have been putting down anywhere from 305-320 to the rear wheels. With a 20% drivetrain loss that's 366-384 at the crank. Has anyone else seen this? He told me this is pretty common because GM doesn't want to hurt 6.2 sales by admitting the 5.3 is a lot closer in power than people think. He's also seeing some great numbers from bolt ons and a tune, nothing mind blowing but still nice gains from the basics.

I'm waiting on my RCSB to arrive and I'm already planning on some basic upgrades, it's nice to know that we are not as far behind ford and dodge as I thought. I'm a die hard GM fan but 355 vs 385 and 395 almost had me looking into other brands.

LongrangeLauber · October 11, 2016

My tuned 5.3 will keep with my buddies 5.7 Hemi. I think he has highway gears though and I have the 3.42's.

Considering this is GM's second biggest V8 in the half ton segment, you should be comparing to the 5.0 Ford (which I think you did above) and if ram has a smaller v8. If you wanna compare the 6.2, gotta do it to the 3.5 egoboost and the 5.7

Rawyzf · October 11, 2016

Those numbers seem high for baseline (at least if you're talking 4wd), are you talking about 2wd?

MSPT · October 11, 2016

All the pulls he does are in 2wd. Most of the trucks would be 4wd if that makes a difference. The closest awd dyno is over 12 hours away so I don't know of anyone locally who has had their truck on a awd dyno

Rawyzf · October 11, 2016

Yeah, I figured the numbers were taken while Dynoing in 2wd. I was just wondering if the trucks themselves were 2wd or 4wd. You will have more drivetrain loss in a 4wd truck on the dyno.

My baseline was in the 270s I believe, but that was not 100% stock. My baseline included AirRaid MIT tube and a catback. They could have cause my baseline to drop, as I was not tuned for them.

SILVER SLED · October 11, 2016

I've heard that and wondered that even more since I wooped my brothers 5.7ltr 4.10 geared 14 Tundra with my 5.3. Even though my 5.3 is tuned. And a 5.3 on e85 is supposedly rated at 385hp.

Rawyzf · October 11, 2016

I have 323hp to the wheels after e85 and tune, so that 385 crank claim from GM on e85 seems about right.

If you add that 25% drivetrain loss into my 323whp, that puts me at 403 crank. So, that seems about right considering I'm tuned as well.

MSPT · October 11, 2016

Interesting stuff, I'm also looking forward to seeing what a 6.2 puts down stock. He has one coming in sometime this month for a few upgrades. Also all these pulls were done on 91 not E85. I'm going to guess his dyno is probably reading a bit high but even so 355hp stock with a 20% drivetrain loss is only 284. Even if they're putting down 300 consistently that's still more than GM advertises. Like someone said above, I think these modern drivelines probably rob closer to 25% than 20%. I'd be interested to see the difference in pulls done in 4wd vs 2wd as well.

Now if they would only sell me a 6.2 in a RCSB I'd be really happy

MSPT · October 11, 2016

Also off topic, but would having a 4wd truck in 2wd still have more drivetrain loss than a 2wd truck would? I got a 4wd because I plan on daily driving it and I've read that you're better off putting the truck in 4 hi than 2wd for drag racing anyways. Not sure how much I like the idea of launching my truck in 4wd but once I get it and the new factor wears off I guess we'll see.

bassJAM · October 11, 2016

Also off topic, but would having a 4wd truck in 2wd still have more drivetrain loss than a 2wd truck would? I got a 4wd because I plan on daily driving it and I've read that you're better off putting the truck in 4 hi than 2wd for drag racing anyways. Not sure how much I like the idea of launching my truck in 4wd but once I get it and the new factor wears off I guess we'll see.

A 4WD will have more drivetrain loss than a 2WD, even if the 4WD is being driven in 2-high.

They're 2 reasons that I can think of, the transfer case will suck up a small amount of power, and heavier all-terrain tires will as well.

It won't matter on a dyno, but having a front axle will add 150 or so lbs to the weight as well.

glcbn · October 11, 2016

Really nice info! Thanks!

Croak · October 11, 2016

I don't have any dyno numbers yet, but as far as not wanting the 5.3 to cannibalize 6.2 sales because they're closer than expected... my buddy has a 2016 5.3 Sierra DCRB and I gap him all day long in my 2015 6.2. No contest. The only stock-ish trucks I've run into out there that concern me are bolt-on RCSB Hemi Rams or tuned 3.5 EcoBoost F150s.

Rawyzf · October 11, 2016

Click the e85 link in my signature. My tuner has done a 6.2 as well and should have baseline numbers.

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Rawyzf · October 11, 2016

I don't have any dyno numbers yet, but as far as not wanting the 5.3 to cannibalize 6.2 sales because they're closer than expected... my buddy has a 2016 5.3 Sierra DCRB and I gap him all day long in my 2015 6.2. No contest. The only stock-ish trucks I've run into out there that concern me are bolt-on RCSB Hemi Rams or tuned 3.5 EcoBoost F150s.

I agree that, GM wouldn't post lower than actual numbers on the 5.3 to help 6.2 sales. The 5.3 is their best seller and they want those numbers looking as good as possible vs the competition.

I would say if anything, GM 6.2 numbers seem a tad low based on how those beasts run and dyno.

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KnappAttack · October 12, 2016

My tuned 5.3 will keep with my buddies 5.7 Hemi. I think he has highway gears though and I have the 3.42's.

Considering this is GM's second biggest V8 in the half ton segment, you should be comparing to the 5.0 Ford (which I think you did above) and if ram has a smaller v8. If you wanna compare the 6.2, gotta do it to the 3.5 egoboost and the 5.7

My stock 14 using E85 will also outrun my buds 5.7 Hemi, when warm in the summer, it flat out annihilates it!

Also off topic, but would having a 4wd truck in 2wd still have more drivetrain loss than a 2wd truck would? I got a 4wd because I plan on daily driving it and I've read that you're better off putting the truck in 4 hi than 2wd for drag racing anyways. Not sure how much I like the idea of launching my truck in 4wd but once I get it and the new factor wears off I guess we'll see.

I have to use 4-HI for drag racing or it just blows the rear tires away. Forget about trying to run in 2 WD. I also shift the six speed manually turning off traction control.