Torque! Rocket power vs LS power

[Northernregal]

I have never disputed any of this, it has to be a tune issue, has to be. GM must be wildly optimistic and obviously only some are hitting the mark. That 6L dyno test was with Holley software, no doubt way better than a stock truck tune. I assumed the lousy low end tune was protecting the fragile 4L60-70E. The shift programming on the 6 spd was also garbage on the 11 with the 5.3, always hunting and never finding low rpm power. My only experience with these motors is the stock truck tune. When I borrowed my Inlaws 04 Avalanche, I ready was to be impressed, wow 295 hp and 335 ft/lbs. It had to be way more than the 307 headed Olds 350 in my 94 Z71, it wasn't where it counted as a truck. I was warned that the head light fell out and along with blowing fuses, it really disappointed me. The only bonus was better mileage. All rest were the same, disappointing. When I finally drove the two 17's, 5.3/8spd wow what a difference, they went like hell. I should have bought my BIL's 17 GMC for the 28K he sold it for, a steal in today's market. Way better mileage than my lousy Dakota.

It is more the trans tuning to be honest. I tinkered with the shift points on my ZR2 blazer with a 4.3 and eventually really like the way it felt. I only increased the shift points by about 20% and the throttle to downshift by about 15% and it was SOOOOO much better feeling.

Once you turf the OEM's multiple layers of redundant safeties, these motors really wake up.

 

[87National]

Once you turf the OEM's multiple layers of redundant safeties, these motors really wake up

Particularly the lq4. The factory tune was extremely conservative.

 

[motorheadmike]

Sorry Mike. It'll be some time before you get your suspender privileges.

Damn, no Red Green for me.

This debate...

 

[olds307 and 403]

Honestly, between these motors feeling way under the rated power, dragging out POS transmissions for too long, cancelling the brands I like and having some of the ugliest cars on the road is why I am not a GM fan anymore. It is no longer the 1970's, Ford's aren't horrible, unreliable, gas guzzling junk anymore. You know how many carbed Ford's were hauled into the dealership flooded, plenty. A 20 year Ford tech commented on since Ford's switch to EFI, how many fewer motors needed rebuilt. Dad was a Ford man who switched, bought a few awful 70's versions. He bought a 75 Cutlass with a 350 Rocket that was abused badly at the end. The 81 Delta 88 with 307 went over 420,000 km, the 307 was still decent. I was working at a Ford dealer in the late 90's as an apprentice, I got Dad to switch back, their cars weren't horrible anymore. Even Dodge no longer has hokey engineering with questionable parts, our Challenger is way better than the 2010 it replaced. The imports aren't tin cans anymore either. GM sh*t the bed years back and has been rolling in it ever since. You go to their show room, they reach on their bed, grab a lump and say you want this, I don't so no thanks GM. There are parts now available for the most reliable 350 motor of the 1970's, like the 1mm ring pack Mahle pistons, roller cams and the soon debuting ultra modern Edelbrock heads. That same motor I posted here will soon have the swap to Edelbrock heads. Mark has the only sets in existence right now. I will post the results, good, bad or indifferent. Unfortunately, I have one of GM's under engineered transmissions behind this 358, that can't survive a 50 year old designs power output without some serious hard part upgrades. Also the unique Type O 8.5" with bolt in axles is strong enough but the aftermarket is minimal and weird. I really don't know why they they picked the 3.08 and 3.23 carrier to work with aftermarket gears. The vast majority of these cars had the 2.56 or 2.78 gears. The performance cars almost all had the 3.42 or 3.91 or the 4 something GM dealer add on ratios. You guys also realize that this is a distraction from my real life situation, this only matters so much in the end.

 

[motorheadmike]

Probably the DBW controls, they are designed to learn to go "lazy" over time to conserve gas. Its one of the many reasons I hate DBW, the response is unpredictable because of the self learning feature .

It is more the trans tuning to be honest. I tinkered with the shift points on my ZR2 blazer with a 4.3 and eventually really like the way it felt. I only increased the shift points by about 20% and the throttle to downshift by about 15% and it was SOOOOO much better feeling.

Once you turf the OEM's multiple layers of redundant safeties, these motors really wake up.

Both of these statements are very true. I remapped both the throttle and transmission (especially delaying TC lock-up) in Natasha's 2015 Colorado to be like the same year V6 Camaro and what do ya know: it stopped driving like crap. Almost sporty. Still way low on torque.

There was a TSB to reprogram the trucks it was so bad.

Come to think of it, now that it is out of warranty, I really should give it the tuning beans. I have a spare upper intake I was going to port, and can hog out the lower one too... might need a turbo since I am in there.

---

On LSeseses. Natasha's '02 Camaro's LS1 (the same unit in the wagon) had a gutless peanut cam from the factory (smaller than the 99-00 cars) and made up the performance difference with intake flow (LS6) as Supercharged111 pointed out. With nothing more than transmission tuning, some light intake and exhaust mods, and some 4.11s that car went mid-12s.

I got called a liar for doing it without a stall converter or internal mods. I just optimized what I had.

 

[olds307 and 403]

Mike, what does LS1 converter stall? I think the intake and exhaust track is also pretty constipated on these trucks as well. Most of the LS series have smaller cams that should produce good torque, so that is confusing as well. Dodge didn't include the better intake or higher compression on the 3.6 in my or any Challenger, like they did the Jeep. It would have made the Pentastar much closer to GM's 3.6 in output. I think the PUG intake, Hellcat Redeye hood in semi gloss black and its air box, the AFE down pipes and a Hemi fever tuned ECM will go in once the extended warranty is up. With all these trips that will come soon enough😈.

 

[Texas82GP]

Stock tuning is extremely conservative. They do this to minimize warranty events and to hit the fuel economy numbers they are looking for. The tune is a huge factor here. And yes, the stock exhaust is very restrictive. The stock muffler on my 08 Sierra was enormous. Probably the same cross section as an overstuffed large duffel bag and at least 3 feet long. Just a cat-back exhaust made a big improvement.

You can't judge the LS based on how it runs in a stock truck. That's similar to judging your 374 by how a stock 307 performs in an Olds 98.

An LS with exhaust and tuning improvements and a small cam runs like hell.

 

[L92 OLDS]

Disagree.

Since you're looking 2013-down years it's really the 8.1L trucks are the ones to get. Gets you a superior motor and out of an ls altogether.

I’ll be the judge of that. My nephew runs a garage for his business. They had five trucks equipped with the 8.1 and he said they all burned oil like mad. Currently I am rebuilding an 8.1 because it self-destructed from detonation. So far I’m not impressed.

 

[ck80]

I’ll be the judge of that. My nephew runs a garage for his business. They had five trucks equipped with the 8.1 and he said they all burned oil like mad. Currently I am rebuilding an 8.1 because it self-destructed from detonation. So far I’m not impressed.

View attachment 183836

Not to poke a hornets nest, but, is your nephew competent? I'll concede the 8.1 uses oil in an era when the ninnys are used to pouring their synthetic in and not opening the dipstick for 10k miles taking things for granted. But usually the loudest complainers have other issues going on

The oil burning is mostly attributed to the integral PCV (no typical pcv valve). They had their TSB about a revised intake service and many guys also added a 45* bend to the internal tube making it harder for oil to get sucked into the intake. (Example of what works on a little 3.8 motor may not be good on a 8.1l)

Are you punching out that 496 into a 540 with the raylar forged bottom end? And/or adding the twin screw blower?

The 8.1 is beautiful at towing and bottom grunt. And, gets better mileage doing it than the ls motors. It really doesn't feel much different driving the truck off a light with 10k in rock behind it versus when it's empty as we found when cleaning a house up for sale.

Big difference between struggling with tons of weight and low torque until you're up over 3000rpm and having even more torque instantly available at 1500rpm from a drivability standpoint.

 

[Northernregal]

The difference with the LS and the Olds, is you can't adjust the LS factory tune with simple hand tools and knowledge. Even moderate tuning completely wakes up the LS equipped vehicles, and dollar to dollar I think they are equivalent in ROI for horsepower to an older motor like an olds, Buick or pontiac mill.