Maximum Speed?
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IN CARS
New member
Speed rated tires?
Can someone help clear this up for me? I was curious about removing the speed limiter on my Sonic simply because this isn't Russia (this isn't Russia, is it?) and because apparently Trifecta can do this. Call it "the Millennium Falcon effect"--the ability to get out of trouble faster than I get into it. But I digress....
Trifecta says they will not remove said limiter unless my tires are Z rated. From the web:
"When Z-speed rated tires were first introduced, they were thought to reflect the highest tire speed rating that would ever be required, in excess of 240 km/h or 149 mph. While Z-speed rated tires are capable of speeds in excess of 149 mph, how far above 149 mph was not identified. That ultimately caused the automotive industry to add W- and Y-speed ratings to identify the tires that meet the needs of new vehicles that have extremely high top-speed capabilities."
The tires I am looking at are W rated. Again, from the web:
"While a Z-speed rating still often appears in the tire size designation of these tires, such as 205/50ZR17 91W, the Z in the size signifies a maximum speed capability in excess of 149 mph, 240 km/h; the W in the service description indicates the tire's 168 mph, 270 km/h maximum speed."
The tires I'm looking at are 205/50ZR17 W93, so I should be good, yes?
This mean they are Z rated, W max, yes? When I asked Trifecta if W ratings were OK (which seemed better than Z) they said no, they had to be Z rated. After some research, I discovered the Z tucked in the tire code, meaning they are Z and W rated. Hate to keep bothering them what with the Christmas rush and all, but want to make sure what I am buying before I do. Any thoughts?
CG
Can someone help clear this up for me? I was curious about removing the speed limiter on my Sonic simply because this isn't Russia (this isn't Russia, is it?) and because apparently Trifecta can do this. Call it "the Millennium Falcon effect"--the ability to get out of trouble faster than I get into it. But I digress....
Trifecta says they will not remove said limiter unless my tires are Z rated. From the web:
"When Z-speed rated tires were first introduced, they were thought to reflect the highest tire speed rating that would ever be required, in excess of 240 km/h or 149 mph. While Z-speed rated tires are capable of speeds in excess of 149 mph, how far above 149 mph was not identified. That ultimately caused the automotive industry to add W- and Y-speed ratings to identify the tires that meet the needs of new vehicles that have extremely high top-speed capabilities."
The tires I am looking at are W rated. Again, from the web:
"While a Z-speed rating still often appears in the tire size designation of these tires, such as 205/50ZR17 91W, the Z in the size signifies a maximum speed capability in excess of 149 mph, 240 km/h; the W in the service description indicates the tire's 168 mph, 270 km/h maximum speed."
The tires I'm looking at are 205/50ZR17 W93, so I should be good, yes?
This mean they are Z rated, W max, yes? When I asked Trifecta if W ratings were OK (which seemed better than Z) they said no, they had to be Z rated. After some research, I discovered the Z tucked in the tire code, meaning they are Z and W rated. Hate to keep bothering them what with the Christmas rush and all, but want to make sure what I am buying before I do. Any thoughts?
CG
Last edited:
Swordsmith
242hp/252 ft-lbs BNR EFI
Still haven't seen an answer to the question:
What, if any, speed limit does the ECU on a stock Sonic prevent the car from reaching?
I know it's over 125, since I've been that fast and no problem. It could be 126, for all I know, or it could be 140 (I think I heard someone say they'd gone 140) or who knows... if there is one at all.
The guys at my local tire dealership laughed when I was worrying about the rated speed on my tires, they said if I was just doing occasional drag strip runs that no tire would have any problem, that the "rated" tires are for prolonged racing at speed, not for short bursts, particularly in a straight line.
What, if any, speed limit does the ECU on a stock Sonic prevent the car from reaching?
I know it's over 125, since I've been that fast and no problem. It could be 126, for all I know, or it could be 140 (I think I heard someone say they'd gone 140) or who knows... if there is one at all.
The guys at my local tire dealership laughed when I was worrying about the rated speed on my tires, they said if I was just doing occasional drag strip runs that no tire would have any problem, that the "rated" tires are for prolonged racing at speed, not for short bursts, particularly in a straight line.
firstorbit84
New member
Yeah, it still hasn't been determined if there is a factory limiter.
If you need to go 125 or more in your sonic, please be on a race track. No matter what tire you've got.
If you need to go 125 or more in your sonic, please be on a race track. No matter what tire you've got.
SonicBoy24
New member
Yes.
The Sedan has Less drag because it has smaller vertical area at the back of the car.
The Hatches have much more drag because they have that huge vertical hatch at the back. the hatch weighs less, but not enough to make a difference at these speeds.
Swordsmith
242hp/252 ft-lbs BNR EFI
Drag limit, though, is for a given hp, not for the car in general, there's not some magic line that says you simply can never push the car past this fast because of drag. With all the different ways Sonic owners on this forum have modified their rides, the only hope for a "drag limit" would be when referring strictly to a stock model, and even then you'd have to take into account which fuel they are running and how far above sea level and how cold it is out and... well, I just don't see a hard and fast "drag limit" being something you can establish.
It is a real thing, though, a question of how hard you can possibly push versus how hard it is to travel that fast thru air, sort of like Terminal Velocity, the speed at which gravity is no longer accelerating you downwards because it's being countered entirely by wind resistance.
What it sounds like Trifecta is saying though is that there's some preset governor in the car, tied to your speedometer, which is going to prevent you from exceeding some predetermined speed, regardless of whether your car and engine is capable of doing so.
I'm mystified at why that speed wouldn't be something unreasonably fast for US highways, like say 100mph. I'm mystified at why, if it's not set down there, at why they would even bother putting one in at all at speeds higher than 125, which is pretty close to drag limit for a stock car. But Vince isn't a fool, and unless he's reading something wrong, or unless we're misunderstanding him, it does sound like there is just such a limit, which he perhaps can and will raise if you send him proof your tires are rated for it.
It is a real thing, though, a question of how hard you can possibly push versus how hard it is to travel that fast thru air, sort of like Terminal Velocity, the speed at which gravity is no longer accelerating you downwards because it's being countered entirely by wind resistance.
What it sounds like Trifecta is saying though is that there's some preset governor in the car, tied to your speedometer, which is going to prevent you from exceeding some predetermined speed, regardless of whether your car and engine is capable of doing so.
I'm mystified at why that speed wouldn't be something unreasonably fast for US highways, like say 100mph. I'm mystified at why, if it's not set down there, at why they would even bother putting one in at all at speeds higher than 125, which is pretty close to drag limit for a stock car. But Vince isn't a fool, and unless he's reading something wrong, or unless we're misunderstanding him, it does sound like there is just such a limit, which he perhaps can and will raise if you send him proof your tires are rated for it.
Swordsmith
242hp/252 ft-lbs BNR EFI
That would be hilarious, I was caution limited at 125, if I was 1 mph away from discovering the hard limit I would just plotz at the irony.
Swordsmith
242hp/252 ft-lbs BNR EFI
If he was pulling away then he wasn't limited to 125. Unless you think his tune removed the limit? Also, how long did it take you to get to 125, is it possible you were drag limited?
SonicBoy24
New member
I have been wondering this since I was old enough to drive...
Swordsmith
242hp/252 ft-lbs BNR EFI
Sounds like you may have hit drag limit then, governor shouldn't have felt like anything until you hit it.
ThatTmoGuy
New member
"drag limited" only means you don't have enough power to battle the forces of drag on the vehicle. Since it is drag limited more power would overcome this effect so you guys running E85 should be able to get well passed 125.
ThatTmoGuy
New member
I would love to go for 130-135 but the cops out here are ruthless if you go over 85.
ThatTmoGuy
New member
Easier said than done.
