Daijoubu
Seasoned Member
Last edited:
Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
BMW is off the charts. At least for the S58. I recall a dyno report on the manual M3 or 4 that had almost the entire listed HP at the wheels, and even more torque than listed. Still good numbers by the LT4 compared to how it is rated.Solid baseline! Seems as though GM might be pulling a page from the BMW playbook and underrating these a bit.
Solid baseline! Seems as though GM might be pulling a page from the BMW playbook and underrating these a bit.
My S58 was awesome, I very much doubted it was putting out the 503hp they advertised. More like 550 at least.BMW is off the charts. At least for the S58. I recall a dyno report on the manual M3 or 4 that had almost the entire listed HP at the wheels, and even more torque than listed. Still good numbers by the LT4 compared to how it is rated.
Can't they claim SAE ratings if they exceed them?Let's be clear: there's no underrating of GM engines since they started SAE ratings back during the LS7 days. Chassis dynos are not good ways to calculate your flywheel HP. Never have been, never will be. Their only proper use is to baseline the car, then do mods, and get another readout.
The engine is making 668HP +/- a very small percentage. Otherwise they can't claim SAE ratings.
Can't they claim SAE ratings if they exceed them?
No, and no launch control either. Just quick, decisive shifts between gears. Been banging gears since I was 15 with a learner's permit (45 now). I can't trigger my brain consistently enough to not do a momentary throttle lift between shifts.@quikag was that with no lift shifting?
I was in the same boat; I never got comfortable with it on my c7 z06. But I forced myself to keep practicing on the 5BW, and I am now a convert! The shifts are just soooo good and sound so nice. Worth it just for the soundNo, and no launch control either. Just quick, decisive shifts between gears. Been banging gears since I was 15 with a learner's permit (45 now). I can't trigger my brain consistently enough to not do a momentary throttle lift between shifts.
I did practice it at Spring Mountain earlier this month with their 5BW six-speed cars, but couldn't get very comfortable with no-lift shift. It did work quite nicely though, so maybe just need to practice more. It's very well developed.
This a German thing, but McLaren also does it. Why? Because they know that advertised horsepower the way everyone else does it only guarantee's that in ideal conditions. They want to advertise their horsepower in the worst possible situation so that you are guaranteed that number even if you were at the bottom of the ocean or on top of Mount Everest. This is why they are underrated, because in the worst possible situation you would get their advertised horsepower but in ideal conditions you get much more.Fair point on SAE. I actually found an earlier edit (not current) version of the SAE J1349 standard and read through it. There is a section that describes how to determine the certified results and it's average of the runs, but the published number needs to occur at least twice in the series. It's interesting to see how comprehensive the testing and reporting standard is.
With that said, it is interesting how BMW in particular seems to outperform expectations of the published numbers. Also, collective pool dyno data seems to support underrating which perpetuates this myth. While the intent of the J1349 is to prevent overrating, it would seem to eliminate underrating simultaneously. At least in the edit I read, I didn't see anything about period sampling of production engines.
@Daijoubu I made 621hp and 598tq on a hub dyno, so I would not think that the dyno you were on is "happy" it seems pretty on par with what I have seen for manual bw5's stockView attachment 15504
View attachment 15503
View attachment 15502A bunch of my BMW friends rented a dyno, so I thought I would tag along and put my car on the rollers if they had time. As you can tell, 620whp and 595ftlb of torque is pretty healthy for a car advertised at 668hp. I don't really think it was a happy dyno either, because a couple of the BWM guys were a little disappointed with their pulls. They were all modified though, so hard to compare. I tried to find someone with a stock Hellcat to come dyno the same day to compare, but to no avail.