A member here posted over in the GS forum, that the "alternative" build/configure tool built by a salesman at a Chevy dealership is now showing a $1300 GG tax for '27 Stingrays/GSs.

Thoughts?

 

Not according to Microsoft Co-Pilot (AI): The new Corvette Grand Sport (GS) is not subject to the Gas Guzzler Tax.

The Gas Guzzler Tax applies only to certain passenger cars that do not meet the required fuel economy standards set by the Energy Tax Act of 1978. Trucks, SUVs, and most sports cars — including the C8 Corvette GS — are exempt from this tax because they were not widely available or used for non‑commercial purposes when the law was enacted U.S. Environmental Protection Agency.

The tax is calculated based on a vehicle’s unadjusted average fuel economy, with rates ranging from about $1,000 to $7,700 depending on how low the mpg is. High‑performance Corvettes like the Z06 and ZR1 are subject to it because their fuel economy is low, but the GS is a more efficient, entry‑level model and falls outside the tax’s scope U.S. Environmental Protection Agency+1.

Bottom line: If you’re buying a Corvette Grand Sport, you won’t have to pay the Gas Guzzler Tax — the cost will be based on the standard federal sales tax and any state/local taxes.

 

 

According to https://www.kbb.com/car-advice/gas-guzzler-tax/, the 2020-2026 Corvette should have a $2100 gas guzzler tax because the combined fuel economy rating of the LT2 is 19mpg. The article also states "Without wading too deep into the weeds, the EPA employs a more comprehensive set of tests when determining the mpg numbers it posts on the Monroney label than it does for identifying gas guzzlers." This is probably why the Z06 has a $2600 and not $4500 GGT.

The LS6 would have to have significantly worse fuel economy than the LT2 to get the tax. With the dual fuel injection set up, I am speculating that GM is getting better fuel economy vs direct injection alone. However, is this moot due to having to feed the extra displacement?

 

I thought the engineers at the Bash touted a 6% increase in efficiency, due to 13:1 CR, etc.

 

Yeah, don’t see how it does get gas guzzler tax when mpg rating should be better making more torque keeping it in V4 mode more during the EPA cycle.

 

That increase was likely referring to combustion efficiency and if it was fuel, it was probably negated by the shorter final drive. I think at best we can hope for the same gas mileage as the LT2.

 

I wouldn't think GM would produce a base Stingray engine subject to the tax, if only for the sake of optics.

 

I agree the 7% final drive increase on the Z51 will offset it, but the base model has the same gearing.

 

without the AFM and auto start/stop the EPA would apply the GGT

 

I would find that surprising if true, considering that new LS6 V8 is supposed to be slightly more fuel-efficient than the LT2 was. Unless it’s only on the Z51 (5.56 gears) equipped Stingrays? Or, the other new models (Grand Sport, 721hp Grand Sport-X, increased truck sales?) have lowered the overall averages and now they’re trying to spread the gas guzzler tax costs across the entire line?
Hoping that it’s just a typo.

 

So the new Stingray and Grand Sport engines have a 13:1 compression ration. What if I can't buy 93 octane, will the engine run OK on 91 octane?

 

Yes, it might just make slightly less power.
Not sure about using 87 octane though?

 

Yes, 93 octane isn’t available everywhere and premium fuel is defined as 91+. The 5.0 in my F150 had 12:1 compression and only required 87 octane though it knocked less on E15/88 octane, but it ran best on E85 as it was flex fuel. The LS6 is going to love liquid corn! The LS6 cam intake lobe is the same they said, but the ICL has been retarded 7* which will help lower DCR.

 

Not sure if that is technically accurate BUT on my E-Ray I NEVER shut off Stop/Start! I also have zero concern of V4 when I drive in MY Mode.
Is it because I don't like paying $5.00/gal, partly. BUT it's mainly a matter of not wanting to wasit energy where it's not needed!

ICEs are VERY inefficient. Only about 15% of the energy in the fuel that you put in the tank goes to propel the car forward. They rest goes to heat coolant, exhaust etc. That includes about 20% of the power that does get to the rear wheels that goes to heat when braking! The E-Ray, as will the GSX does recover some of that wasted braking energy.

So does Stop/Start help mpg! Jason Fenske (Engineering Explained) in a "Reel Video" summarized recent SAE tests that showed in "real world testing" they saved from 4 to 8.7% using Stop/Start versus not. My wife has had Stop/Start on several BMW X5 SUVs and we have never turned it off. No need, it's unobtrusive. So is the E-Ray Stop/Start. Can't get your foot from Brake to Gas Pedal before the cars starts! (BTW Jason comments with a smile, that engineers can use electric starter motors that last! One augment I hear as well, perhaps with some old systems!) BTW Josh Holder in In an After Bash Steve Garrett Podcast also noted the front wheels also start moving hybrids forward when your foot leaves the brake pedal. That is when my wife's BMW and the E-Ray ICE start! Not when it gets to the gas pedal!

Nope it's not just money but I "feel good" knowing when I use my right foot for fun (which I do often) some of the fuel I waste was from some I saved!

 

Looks like, as of today, the GGT on that configurator has been removed.

 

Did they ever explain the afm design/system on the new LS6 yet?

Could the GGT could be for full aero cars only?

 

It is removed from GS, but still showing under Stingray (which wouldn't be true). Who knows.

 

Who cares... been there, done that.

 

Wait.

Has it been confirmed that the ‘27 LS6 Corvettes will have A.S.S.? If true I must have missed it.