JerryU

Made what was just a simple table that presented data points I picked from the two graphs- - into a spreadsheet that used RPM and Torque to calculate HP! i.e. HP = (Torque x RPM)/5252

Now the only thing in question is my interpolation of Torque and RPM values from the graphs!
Here is the result:


Adjusted two Torque values from my estimate made from the graphs to match the reported HP@RPM published data. My eyeballs can't interpolate to more than +-5!!

redzone

Actually, the ZR1 makes 145 pounds of lift, zero DF. The Stingray and stage 1 Z06 are very close to neutral while the Z06/Z07 has ~400 pounds of DF with 80% of that due to rear spoiler design.

All info gleaned from GM.

JerryU

Be careful, you may get an undesirable result with the higher hp asked for! I'll explain.

Bought a stripped down Chevy S10 truck when we were building our new house, served it's purpose. Loved the truck but found a new metallic silver, Step Side S10 with all possible options including: 2 inch lowered ZQ8 suspension, "axle hop damper shock," quick steering, stiffer frame, Positraction, larger aluminum wheels and wider tires, high end interior, etc. It also had ~20 more advertised HP (with the same cid V6.) Dealer was having a hard time selling it because it had a standard shift. Perfect for me at a very good price!

However when merging to a 4 lane divided highway from our street it bogged, if I did not use much more throttle than my older stripped down S10! Brought it to the dealer and fortunately the Service Manager was a drag racer! He drove it and said, "Yep they have provided more top end power but scarified low end torque."

He suggested getting a Hypertech programmer and set it for 93 octane. I also installed a Hypertech suggested 160 degree thermostat, added an MSD ignition, dual exhausts and a K&N air cleaner with a modified air intake duct. That significantly improved low end torque and power. No longer needed half throttle to enter the highway!

Looking at my above post #41, would not want that "extra power" all at the top end. Hard to have your cake and eat it too! GM has done a great job with the LT1 in balancing low end torque and high end hp. The variable cam timing is definitely a benefit. As noted GM had to eliminate it with the LT376/535! Great for racing but not for the street, IMO and experience.

dovervold

Lingenfelter's H/C package dyno'd 461 rwhp/422 rwtq (vetteweb.com May 2016). Pretty consistent with this 535 package. Higher rev's and HP but not much TQ. LT1 is pretty effecient stock so not seeing the big gains like the LS platform.

I did bolt ons and got 435/435 and the car screams. For 13K I would trade up to a new GS and swap out my headers and intake from my Z51

JerryU

Long tube headers, modified throttle body and low restriction air intake would retain the variable cam timing and with a good tune get the best of both worlds!

thegame

Just get an ECS kit and call it a day!

DickieDoo

Doesn't have AFM ! that's where half the HP comes from!

djnice

Is the LT376/535 compatible with dry sump?

JerryU

Good point, most (if not all) Chevy crate engines are wet sump!

This engine isn't really meant for a Vette. Looks like you could achieve that power with an aftermarket cam, lifters, a set of large port heads, etc. and keep your dry sump.

DickieDoo

Interestingly, the torque on this motor doesn't fall off as compared to the LT1 so this is truly a track motor... should be part of the Z07 package on the GS. I bet we'll see an HP/TRQ increase in 2018. 485/480 would be a real nice number... just strong enough to notice and make us want to trade up!

stevebz06

I wasted a lot of time trying to explain that HP is simply derived from torque (which explains why the two curves ALWAYS cross at 5252 rpm), but I got nowhere.

lakemg

I seriously doubt that you'd even feel the increase in power going from current output to 485/480, since you're only looking at a 5.4 % increase. You'd see a slight improvement in track times, but not night and day. Increase it 50 HP/TQ and it would be more worthwhile in my opinion. But as stated, for street use, I'm perfectly fine with what the general gave us. Hell 65 mph comes super quick on the street and anything faster than that around here will quickly trigger the blue lights behind you...

stevebz06

So, let's see; you guys want an engine that has pushrod valve activation, normally aspirated, 6.2 liters in displacement that is cheap and runs reliably for hundreds of thousands of miles with good economy and makes over 500 ft pounds of torque at low rpm and almost 600 hp at high rpm.

No sweat! We'll get right on it!

Niw, I'm not going to claim to be a cam designer, but it's obvious that they were looking to gain hp, and without resorting to tricks like vvt and FI, they had to rely on a cam that was intended for high rpm operation with a lot of overlap. When a cam has a lot of overlap, low rpm performance suffers because cylinder pressure is lost out of open valves. To get a performance advantage out of this engine, you'll need to keep the thing spinning pretty fast.

There is a technology that is being worked on that looks like it might fix this weakness of internal combustion engines where you could have a torquey low rpm engine along with screaming high rpm power all in the same unit, and that is electrically actuated valves. There are some running prototypes and the results look very good. It gets rid of the cam, pushrods, probably don't need rocker arms. Very interesting technology if it is reliable enough.

JerryU

Yep in post #41 showed the simple equation and as you say hp is just a derived value from torque and rpm.

I had put a table in showing torque and hp by just picking values from GM graphs for the LT1 and LT376/535 engines. Best interpolation that can be made from those graphs is =-5! In post #41 just estimated torque and rpm and calculated hp in a spreadsheet. At least it provides the two data points (working backwards) that GM published for their peak HP.

The relative point is the same - the LT376/535 just pushes the curves higher in good hot rod fashion!

How if we could eliminate valve springs and use pressurized nitrogen to manage valve closing we could get get closer to the the hp/cid of F1 engines! This is a video of various Honda F1 engines operating up to 21,000 rpm!

sunsalem

Great video...thanx.

marcouvo

Probably not tuned right -- lean in the mid-range. And that's too big a cam for a mild street application, IMO.

JerryU

But it also reflects the great engineering in the current LT1. Decided to look at the original LT1.

Recalled Duntov was always trying to achieve 1 hp/cid. And that was Gross HP in the day. The industry switched in the 1971/1972 time frame as evidenced by the comparison of power in the LT1 in those two years.

Today all power is measured as Net. Note the 2014 LT1 far exceeds the old engine! Squeezing more power across the rpm range is not easy! Also note, looking at torque at one rpm is not really relevant to the engines performance. Have to look at the power graphs, area under the curve etc, depending on how the car will be used.


Comparing 2014-2017 LT1 with LT1 engines of old and the LT376/535

LoganExplosion

nobody ever wants to talk about the LT1 from the 90s. haha
It DIDN'T EXIST!

Suns_PSD

That would be the perfect drivetrain for the GS obviously even though I'd have rather had a 427 version. Maybe next year.

stevebz06

Those 3 liter NA F1 engines from the 90's positively make the current engines sound like appliances.