Mpg
Le Mans Master
Joined: Aug 2000
Posts: 6,486
Likes: 1,659
From: Las Vegas NV
It's the GS's bigger/heavier tires which have more rolling resistance and inertia to overcome than the Stingray-sized tires.
Weight? There's not enough weight difference between a Z51 and a GS to make a noticeable difference, and any increased fuel consumption from the tiny drag increase from the wider body is non-existent in town and likely less than 1mpg at legal highway speeds.
Drifting
Joined: Aug 2015
Posts: 1,434
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From: Maple Ontario
It's the GS's bigger/heavier tires which have more rolling resistance and inertia to overcome than the Stingray-sized tires.
Weight? There's not enough weight difference between a Z51 and a GS to make a noticeable difference, and any increased fuel consumption from the tiny drag increase from the wider body is non-existent in town and likely less than 1mpg at legal highway speeds.
Le Mans Master
Joined: Aug 2000
Posts: 6,486
Likes: 1,659
From: Las Vegas NV
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Racer
Joined: Dec 2005
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From: Hertford NC
Drifting
Joined: Aug 2015
Posts: 1,434
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From: Maple Ontario
1: weight and rotational mass Bigger Rim is heavier
2: Wider = more aerodynamic drag.
Case in point, on my Cadillac Escalade the jump from 18" to 22" makes a significant difference in fuel economy. I will have to look that one up . BUT, going back to the 288/45R22 from a 305/40R22 made a significant difference in throttle resonse and fuel economy 0.5 L/100Km better... which is a bit less than 1MPG but with just a change back to OEM size, that's pretty significant.
Le Mans Master
Joined: Aug 2000
Posts: 6,486
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From: Las Vegas NV
Z51 vs Stingray (M7): Same rear end gears, but Z51 has slightly numerically higher transmission gears (except 5th gear, which is actually numerically lower than non-z51, inexplicably).
The differences are slight, especially above 3rd gear, so I'd be quite surprised if there was a noticeable mpg hit.
I didn't notice in any of GM's literature that the Z51 had a lower MPG than non-Z51, but it's possible that I missed it.
The differences are slight, especially above 3rd gear, so I'd be quite surprised if there was a noticeable mpg hit.
I didn't notice in any of GM's literature that the Z51 had a lower MPG than non-Z51, but it's possible that I missed it.
Instructor
Joined: Sep 2013
Posts: 103
Likes: 11
A larger diameter tire could increase highway fuel economy as the overall drive ratio decreases. Said another way, a larger tire diameter would reduce engine revs vs a smaller tire diameter. Lower revs typically (not quite always) raises mpg.
However, as mentioned above me, a larger diameter tire and also a wider tire has more inertia requiring more fuel to accelerate and lowering mpg.
GS has wider body than Stingray or Z51 and a bit more drag, decreasing mpg more.
A more aggressive aero package would also decrease mpg.
For some reason, I can't find gear ratios in the GS. As mentioned above though, if gears are longer, then the lower engine speed should raise mpg.
However, as mentioned above me, a larger diameter tire and also a wider tire has more inertia requiring more fuel to accelerate and lowering mpg.
GS has wider body than Stingray or Z51 and a bit more drag, decreasing mpg more.
A more aggressive aero package would also decrease mpg.
For some reason, I can't find gear ratios in the GS. As mentioned above though, if gears are longer, then the lower engine speed should raise mpg.
