[arpad_m]

Originally Posted by asthmamax11

GM should have paired the LT4 with a 2.3 or 2.65 in the first place

$$$, they probably got a sweet deal from Eaton on the puny 1.7.

[AMOR]

Maybe it’s because a larger supercharger spins slower?
And the 1.7 TVS was selected so that car is more responsive throughout RPM range?

[NG329]

Originally Posted by AMOR

Maybe it’s because a larger supercharger spins slower?
And the 1.7 TVS was selected so that car is more responsive throughout RPM range?

Nah, I doubt it as the Corvette ZR1 runs a 2.6L supercharger.

[CW3SF]

I get that the larger one has more headroom (potential) up top but I really like how hard the little 1.7L hits. And unless you are are racing A lot it’s hard to make use of power over ~750 wheel anyways. JMHO

[Joshinator99]

Originally Posted by arpad_m

$$$, they probably got a sweet deal from Eaton on the puny 1.7.

Originally Posted by AMOR

Maybe it’s because a larger supercharger spins slower?
And the 1.7 TVS was selected so that car is more responsive throughout RPM range?

My understanding was that GM wanted the smallest supercharger possible due to Z06 packaging challenges and minimizing parasitic draw. They actually started with an even smaller rotor pack than 1740, then stretched the rotor pack size to 1740 when they realized they were going to have trouble hitting their 650 BHP target for the car.

[Z OH 6]

Originally Posted by NG329

Nah, I doubt it as the Corvette ZR1 runs a 2.6L supercharger.

It had a much higher power target than the ZL1 so that's the difference.

[Joshinator99]

Originally Posted by Z OH 6

It had a much higher power target than the ZL1 so that's the difference.

[FRANK121]

Originally Posted by NG329

Nah, I doubt it as the Corvette ZR1 runs a 2.6L supercharger.

Speaking of that, Can a 2.6L ZR1 Supercharger fit our ZL1

[JSH]

Originally Posted by FRANK121

Speaking of that, Can a 2.6L ZR1 Supercharger fit our ZL1

Yes. It's early here and my coffee is still full, but this site has at least 10,000 posts on that topic. It's actually 2.65L or 2650cc. Magnuson's fits easily, Edelbrock's requires a notched hood.

[KingLT1]

GM didn't use the 1.74 because they got a sweet deal on it... LOL. It's actually more efficient then the 1.9 LSA used on the 5th gen CTS-V and ZL1. Also bigger isn't always better. Sizing the supercharger correctly for the power goal and intended use is important. The 1.74 @ 9psi peak would be faster and more responsive then the 2650 pullied for 9psi peak. The Z06's cooling issues had nothing to do with the supercharger...it's the lack of airflow across the motor hence why GM added the huge Nostrils to the front bumper of the ZR1. The 2650 on the ZR1 produces 15psi stock to hit 750bhp. That is where the 2650 starts to shine.

[radz28]

Originally Posted by KingLT1

GM didn't use the 1.74 because they got a sweet deal on it... LOL. It's actually more efficient then the 1.9 LSA used on the 5th gen CTS-V and ZL1. Also bigger isn't always better. Sizing the supercharger correctly for the power goal and intended use is important. The 1.74 @ 9psi peak would be faster and more responsive then the 2650 pullied for 9psi peak. The Z06's cooling issues had nothing to do with the supercharger...it's the lack of airflow across the motor hence why GM added the huge Nostrils to the front bumper of the ZR1. The 2650 on the ZR1 produces 15psi stock to hit 750bhp. That is where the 2650 starts to shine.

Isn't about 15-psi what the GT500 runs, too? It seems like that's the sweet part of the efficiency island of this blower.

[Idaho2018GTPremium]

Originally Posted by AMOR

Maybe it’s because a larger supercharger spins slower?
And the 1.7 TVS was selected so that car is more responsive throughout RPM range?

You’re onto it. GM Performance selected the 1.74 because of its smaller size, they were able to pack the intercoolers between the rotors and heads, instead of on top, lowering the center of gravity. It is also more efficient and ~30 lbs lighter than the LS9 blower (6th Gen ZR-1 engine), and has 9% more intercooler capacity, despite the small size. The main reason though, is with the 1.74 (custom size, btw), they were able to beat the peak hp of the 6th Gen ZR1, and destroy it in torque in the midrange. The small 1.74 liter blower met GM’s power goals for the Z06 that it was developed for. They knew all along they were doing a 7th Gen ZR-1, so they had to leave some on the table for the LT5.

LT4 met GM’s goals for the installation. Plain and simple.

[SATINSTEEL1LE]

Magnuson tune vs Teds tune. Yeah.

[arpad_m]

Thanks for the information, guys. I will add that the 2650 obviously didn't exist 6-7 years ago when that blower decision was probably made, so its optimal performance range is irrelevant, but I do see the points made about these optimizations and meeting design goals.

Originally Posted by Idaho2018GTPremium

The main reason though, is with the 1.74 (custom size, btw), they were able to beat the peak hp of the 6th Gen ZR1, and destroy it in torque in the midrange.

The C6 ZR1 blower has 40-45 lb-ft less torque in the midrange from approx. 2000 to 5500 rpm (and for a 3300-pound car vs a 3900-pound one), this is nowhere near the difference I'd use the term "destroy" for, after all, we're on a forum and not youtube/twitter/instagram/tiktok