Engine Sound C7 ZR1

[1971 Judge]

Originally Posted by Hib Halverson

You are never gong to hear the S/C noise over the exhaust with the bypasses open and the engine being run as hard as the driver (probably Jim Mero) is driving the car.

Plus, I think it's unlikely the 4G ZR-1's engine could make 750-hp and pass emissions without being supercharged or turbocharged.

Astute observation! I concur....wish it was N/A, but it will be forced induction per Hib's comments above.

[Ryan Chappel]

There is a video on You Tube(I'll try to re-find) of a ZR1 at Nurburgring and the car definitely has some kind of waste-gate or popoff valve pop when shifted...gotta be some power-adder there.

[Hib Halverson]

I spent a lot of time watching/listening to that footage. Couple things I noted...

1) There is littlie doubt in my mind the engine is supercharged because you can hear the blower whine and those two big air intakes at each side of the front fascia are likely bigger charge air coolers.

2) I heard no "pop-off" valve or wast gate but I did here the typical "drop-throttle cackle" one often hears from C6/C7s with bypass exhausts when you lift at high rpm.

3) The car is loud. in fact, it sounds just like my '12 Z06. I uses a stock exhaust system, but with a backdated, 2-cat mid-section off an '11 to replace the stock, 4-cat mid-section which came on a '12. That coupled with the lower-restriction '12/'13 mufflers makes the car louder when the bypasses are open and makes the cackle louder, too.

4) Sounds like the engine in that car has a somewhat higher rev-limit which doesn't surprise me because they may need to turn the engine faster to gain some power. I'm going to bet that "LT4+" has stuff like an upgraded rotating assembly, Cadillac racing valve lifters, upgraded valve train and etc.

Let me know what you think.

[XfireZ51]

Hib,

There's been photographic evidence of the C7 ZR prototypes wearing
ZR1 Supercharged badges on the fender, I believe the center cap also says the same on the new "zr1 star wheels". The wheels themselves have zr1 as part of the casting.

[Hog]

Originally Posted by Hib Halverson

I spent a lot of time watching/listening to that footage. Couple things I noted...

1) There is littlie doubt in my mind the engine is supercharged because you can hear the blower whine and those two big air intakes at each side of the front fascia are likely bigger charge air coolers.

2) I heard no "pop-off" valve or wast gate but I did here the typical "drop-throttle cackle" one often hears from C6/C7s with bypass exhausts when you lift at high rpm.

3) The car is loud. in fact, it sounds just like my '12 Z06. I uses a stock exhaust system, but with a backdated, 2-cat mid-section off an '11 to replace the stock, 4-cat mid-section which came on a '12. That coupled with the lower-restriction '12/'13 mufflers makes the car louder when the bypasses are open and makes the cackle louder, too.

4) Sounds like the engine in that car has a somewhat higher rev-limit which doesn't surprise me because they may need to turn the engine faster to gain some power. I'm going to bet that "LT4+" has stuff like an upgraded rotating assembly, Cadillac racing valve lifters, upgraded valve train and etc.

Let me know what you think.

Considering thet the LT4 wears upgraded components as compared to the 14 LT1, I'd bet you are correct. When comparing the LT4 to the LS9, the LS9 does include more "exotic" componentry.
The R1740 TVS 1.7L supercharger of the LT4 spins at up to 20,150 rpm – 5,000 rpm more than the supercharger on the previous 2.3 liter LS9 engine. With 9.4 vs. 9.7psi of boost pressure LT4 vs. LS9.


LS9 was redlined at 6600rpm, GEN 5 LT4 is the same at 6600rpm for fuel shutoff.
We'll probably see forged aluminum pistons, like the GEN IV Ls9 and GEN V LT4, the only other modern GM V8 engines to use such pistons.


Itll be interesting to see whats inside the new GEN V SBC engine.

[XfireZ51]

Paul,

If in fact the C7 ZR is using an LT4 w a larger blower, it will be interesting to see what differentiates this car from a Z06 sufficiently to warrant the premium
No doubt Chevy will be asking. Chevy never published the Ring times of the Z06.
Disappointing? Now maybe a balls out track version?