Either the CTS-V will make more than 550hp or this is a very inefficient supercharger
Just brainstorming here with some ricer math.
The LSA is basically a low compression LS3 motor, right?
LS3 makes about 430hp @ 10.7:1 compression.
LSA makes about 550hp @ 9.1:1 compression.
If you made the LS3 down to about 9.1:1 as a naturally aspirated motor, it would lose 1.6 points of compression, and each full point is worth about 4%.....so dropping the LS3 down to 9.1:1 compression would bring N/A hp to about 400-405hp.
Now, the CTS-V is going to run 9psi on 9.1:1 compression......
So boost is what would bring up this theoretical 400-405hp motor to 550hp. That's a 150hp gain with 9psi. That's about 15.5hp gain per pound of boost.
That seems kind of weak to me. Maybe GM really cranked the timing down, but still. That doesn't seem very efficient for a blower on a hp/psi measure, especially for a 6.2L motor.
Re: Either the CTS-V will make more than 550hp or this is a very inefficient supercha
I think you are onto something. I am just wondering if it is derated, or Caddy is sandbagging so the Germans are shooting at a low target with their counter stroke. Or it just has a lot of easy hp to gain for when the answering counterstroke comes. I suspect the LSA will be capable of 600-650, and the LS9 700-800.
Re: Either the CTS-V will make more than 550hp or this is a very inefficient supercha
You guys are digging pretty good for this one. Keep in mind that the recommended, not required, fuel for this vehicle is 91/92 but it will run on 87!! They have a secondary fuel map that the vehicle will switch to when it needs to. The engine most likely runs full timing when the conditions are just right. They (GM) can kill power at will via the timing. So the boost really isn't as important as one would make out. Plus the boost reading is most likely taken before the intercooler, meaning the engine is most likely only seeing about 7-7.5 psi. Bottom line is the blower is very efficient. Its the tune that alters the numbers....
Thanks,
Dr. Design
D3 Cadillac
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Re: Either the CTS-V will make more than 550hp or this is a very inefficient supercha
Quote:
Originally Posted by BLACK_CTSV
So, it sounds like there may be some very low hanging fruit to be had with a tune...
You bet. Timing makes all the difference in the world on a blower motor if everything else component wise is set up efficiently. They will yank a lot for heat soak, fuel grade and torque management. Lots or cars run on this principle right now. It's easier to pull timing and put it back in within milliseconds rather than bleed boost off through the waste gate and wait for repressurization, only to have to adjust the computer to its' effects.
I'll bet we'll see 10-12 degrees in spots and the car will be running around 10:1 AFR.
Re: Either the CTS-V will make more than 550hp or this is a very inefficient supercha
Quote:
Originally Posted by Dr. Design
You guys are digging pretty good for this one. Keep in mind that the recommended, not required, fuel for this vehicle is 91/92 but it will run on 87!! They have a secondary fuel map that the vehicle will switch to when it needs to. The engine most likely runs full timing when the conditions are just right. They (GM) can kill power at will via the timing. So the boost really isn't as important as one would make out. Plus the boost reading is most likely taken before the intercooler, meaning the engine is most likely only seeing about 7-7.5 psi. Bottom line is the blower is very efficient. Its the tune that alters the numbers....
Thanks,
Dr. Design
D3 Cadillac
Aren't most cars' boost levels rated before the IC anyway? I hear you on GM killing timing.....with only a 1.5psi difference between the LS9 and LSA, something else has to make up the 70hp difference....