Engine Output comparisons(splinter thread)

[Hog]

In order to not muddle up what is promising to be an excellent thread about stock cube LT5s, I am starting this splinter thread.


Here is Todds Stock 350 cube thread
http://www.zr1.net/forum/showthread.php?t=28786&page=2


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Originally Posted by tpepmeie

You guys know what I think about converting rwhp on a dynojet to brake horsepower on an Engine dyno...

Originally Posted by efnfast

Sure Todd, but that's all most of us can do. -Steve

Originally Posted by tpepmeie

427 LT5 build 1 observations

• 1/19/2011: SF901 Engine Dyno, 300 rpm/sec, SAE1349 correction - 669 bhp [703 using STP correction]
• 8/9/2012: Dynojet shop "A", SAE1349 correction - 637.2 rwhp
• 5/10/2013: Dynojet shop "A", SAE1349 correction - 638.2 rwhp
• 5/10/2013: Dynojet shop "B", SAE1349 correction - 634.1 rwhp

I realize this is but one like-for-like comparison, but three different chassis dyno tests, across two days and two shops, and nearly 1 year apart. the variance is 4 hp.

The same engine, on the superflow engine dyno, at the same atmospheric correction, was only 30-35 hp higher. Maybe that engine dyno is a bit stingy? However, using the internet accepted 15% driveline loss, that engine should have made close to 750 brake horsepower on the engine dyno. Unlikely.

I've tested a couple others on that engine dyno, but unfortunately haven't done a chassis dyno on those. Not my engines, so not so easy to do the comparison testing.

Sorry, didn't mean to get off topic. I'm expecting a solid 550-560 brake hp out of this cammed 350 cid project.

Originally Posted by Top Toy

Engine dyno numbers don't make good comparison points, either, because you're no longer using using the in car accessories (IAF housing, exhaust, cooling, drivetrain et al). The only valid comparison is SAE on the same day and same chassis dyno. Should also be based on area under the curve to account for the full range of operation, not just a one point spike or engine tuned for peak HP only. Anyone up for a shoot out? [emoji6]

Sent from my HTC U11 using Tapatalk

An engine dynoing 600hp@6000rpm/650 torque@2500 will still outaccelerate an engine that dynos at 550hp@6000rpm/600lb/ft torque @ 2500 rpm once you get both cars into the car, the same car that is.


The great equalizer came for Model Year (2006) when Chev voluntarily made the GEN IV SBC 7.0/427 the very 1st engine to officially use the SAE CERTIFIED Power rating SAE J1349.
Many Japanese engines lost engine power while many North American cars increased. No more rounding up toth nearest 10 horsepower, no more using an oil sump with 2 literrs of oilmissing, no more stone cold engine temps for testing.


Before J1349 the LS7 was 500 hp at 6,300 RPM with 475 lb.-ft. of torque.







After SAE Certified Power it was 505HP @ rpm and 470 lb/ft torque







The application that has the biggest diffrence for GM has to be the Cadillac Northstar LC3 supercharged VVT engine. in the XLR its rated at 443hp@6400rpms and 414lb/ft@3900rpms and the SAME engine in the Cadillac STS is rated at 469hp@6400rpm 439@3900rpm.
These differences come from different intakes and exhausts forced upon the engines due to the different vehicle packages.


I still cant believe the SAE Certified power numbers for the 2019+ LT5, which is pretty much a warmed over LT4, with a slowed down blower that makes 13.9psi of boost being fueled by 8 Direct Injection squirters for conventional cruising idling duties and using a separate fueling controller, the 8 conventional port fuel injectors come online 2hen the boost starts a flowing.
Hey at least the "new" LT5 got 16 injectors.