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If you watch the Steve Garrett podcast, right after last year's BASH (still available) you'll find more info about the E-Ray in that 1hr interview of Tadge, Josh Holder and Harlan Charles than anything written. Need to see what all three say in context of how unusual it was for a model to have the same settings with and without summer tires.
CorvetteBlogger is NOT a GM source. Like many they are not always right. And if you read the GM ZER description it has a different part number for the suspension and alludes it may be more.
Steve Garrett asked for questions for his next Podcast with the trio. I listed that as one of three. That included one about how well Stop/Start works. Like my wife's BMW SUV I don't hear the starter motor. Was informed by a very smart BMW Service Writer, who reinforced what I read some car companies use to restart after a short stop, It captures combustion pressure near TDC when it stops and that is what turns the motor over as soon as your foot is off the brake pedal.
I find the same with the E-Ray, mostly don't hear the starter motor. Before I could possibly get my foot from the brake to gas pedal the engine is started ad car moving forward. Asked if it (similar to the Coffman Starter used on plane and tanks in WWII and apparently the only way to start the British Spitfire) is what is being used.
A Draggy can't deal even with small inclines. Understandable as GPS satellites at 12,500 miles away. Just look at the trig numbers and you see why it cannot compensate.
GM uses a matrix of accelerometers to supply signals to the MRC etc. Accelerometers don't care about inclines, etc. Very accurate. Now I don't know if the dash 0 to 60 mph test display (that was not on my 2020 C8 Z51 but is my E-Ray) uses accelerometers or the PDR. But GM pays nothing for accelerometers that are generating signals they can use. Don't know what they pay Cosworth for the PDR and for what they can use for whatever fee.
Nope just because it uses the Cell Phone some think is an appendage to their body does not make it the "be-all and end-all devise" for supper accuracy!
Don't have an answer, someone will have to find out from GM.
A Draggy can't deal even with small inclines. Understandable as GPS satellites at 12,500 miles away. Just look at the trig numbers and you see why it cannot compensate.
GM uses a matrix of accelerometers to supply signals to the MRC etc. Accelerometers don't care about inclines, etc. Very accurate. Now I don't know if the dash 0 to 60 mph test display (that was not on my 2020 C8 Z51 but is my E-Ray) uses accelerometers or the PDR. But GM pays nothing for accelerometers that are generating signals they can use. Don't know what they pay Cosworth for the PDR and for what they can use for whatever fee.
Nope just because it uses the Cell Phone some think is an appendage to their body does not make it the "be-all and end-all devise" for supper accuracy!
Don't have an answer, someone will have to find out from GM.
The Dragy produces accurate numbers with inclines, it just tells you they are not valid and shows you the incline/decline.
Obviously times are much better going downhill.
The in-car PDR is just for amusement purposes, it is not accurate consistently.
I find it is off by a minimum of 0.2-0.3 most of the time, 0.5 some of the time, it is always overly optimistic.
Think about it, would most Corvette owners rather tell his friends his car does 0-60 in 2.8 or 3.3?
The Dragy produces accurate numbers with inclines, it just tells you they are not valid and shows you the incline/decline.
Obviously times are much better going downhill.
The in-car PDR is just for amusement purposes, it is not accurate consistently.
I find it is off by a minimum of 0.2-0.3 most of the time, 0.5 some of the time, it is always overly optimistic.
Think about it, would most Corvette owners rather tell his friends his car does 0-60 in 2.8 or 3.3?
I prefer to be accurate.
No from what I read. It can't deal with any slope accurately! Sure compared to drag strip number folks like to plot it's close. BUT drag strips are flat! Second no one has any idea if the GM dash test is using the PDR. They pay Cosworth something for that and for what use we don't know. An accelerometer doesn't care about slope and GM using those to control MRC for example NOT some satellite 12,500 miles in the sky. Heck my G-Tech Pro (I used 23 years ago when setting up launch of my 8.2 Liter BB Street Rod) uses an accelerometer, and I did not need a cell phone or high in the sky satellites. Great comparative.
BUT I'll end this silly discussion because we don't know what GM is using. Until then, fire away after all, it uses your Cell Phone and that can't be wrong! .
From what I've read, Dragy uses a number of sensors (GPS, Accelerometer, Gyroscope), likely all used for different purposes working in unison to generate it's data. GPS for knowing location / altitude, Accelerometer for sensing the start of movement, etc. I haven't reached out the manufacturer, but multiple reviews of how it works talks about multiple sensors working in tandem.
It can deal with slopes. It even records the amount of incline or decline.
It's just, if you have a decline it will 'invalidate' the results as the time will read faster (accurately) than it would have if it was a flat road.
Originally Posted by JerryU
No from what I read. It can't deal with any slope accurately! Sure compared to drag strip number folks like to plot it's close. BUT drag strips are flat! Second no one has any idea if the GM dash test is using the PDR. They pay Cosworth something for that and for what use we don't know. An accelerometer doesn't care about slope and GM using those to control MRC for example NOT some satellite 12,500 miles in the sky. Heck my G-Tech Pro (I used 23 years ago when setting up launch of my 8.2 Liter BB Street Rod) uses an accelerometer, and I did not need a cell phone or high in the sky satellites. Great comparative.
BUT I'll end this silly discussion because we don't know what GM is using. Until then, fire away after all, it uses your Cell Phone and that can't be wrong! .
From what I've read, Dragy uses a number of sensors (GPS, Accelerometer, Gyroscope), likely all used for different purposes working in unison to generate it's data. GPS for knowing location / altitude, Accelerometer for sensing the start of movement, etc. I haven't reached out the manufacturer, but multiple reviews of how it works talks about multiple sensors working in tandem.
If it used an Accelerometer that would be different that I read. Dragyuses high speed GPS satellites to accurately measure your vehicles performance within 1/100th of a second.
BUT a BMW source noted: "In testing we conducted at PBIR with 3 different Dragys, it was within 0.04s for the 1/4 mile time."
However a Youtuber who was promoting a Dragy compared it to 1/4 mile accurate light beam data and , said it was very good. BUT then said it varied and in some cases it was within a 10th. His bottom line was you can buy below.
I'm not trying to say the Dragy isn't good BUT IF GM is using an accelerometer which is what is used for MRC etc, it may also be close. Don't know until someone from GM says just how the "new to me" dash test" in my E-Ray operates and hopefully it's accuracy.
SIDEBAR
I started this Thread to show without Lauch Control I matched the GM Spec of 2.5 seconds. Jason Cammisa with no doubt GM techs/marketing present, showed in the Hagerty Video versus Ferrari and Lambo 2.4 seconds 0 to 60 in the GM display. Little doubt they were using launch control but as he noted on an unprepared Track.
Bear quoted GM Folks who said at the GM proving ground, using Z06 Wheels and Tires (probably low inertia Carbon Fiber wheels and Cup2 R's) they were doing 2.1 seconds.
Some who posted on the Tread give the impression they don't want to believe these numbers. So beit!
No from what I read. It can't deal with any slope accurately! Sure compared to drag strip number folks like to plot it's close. BUT drag strips are flat! Second no one has any idea if the GM dash test is using the PDR. They pay Cosworth something for that and for what use we don't know. An accelerometer doesn't care about slope and GM using those to control MRC for example NOT some satellite 12,500 miles in the sky. Heck my G-Tech Pro (I used 23 years ago when setting up launch of my 8.2 Liter BB Street Rod) uses an accelerometer, and I did not need a cell phone or high in the sky satellites. Great comparative.
BUT I'll end this silly discussion because we don't know what GM is using. Until then, fire away after all, it uses your Cell Phone and that can't be wrong! .
They don’t use PDR as it doesn’t match timer, so which is accurate?
Thought I'd add to my 2.5 second 0 to 60 test runs (using the GM test in the E-Ray dash screen, so data is relative to my prior tests.)
Now have ~1050 miles and outside temp today 85F. Had my cousin in the car- 190 lbs versus prior no passenger for prior 2.5 second result.
Tried several quick attempts on a two lane road no traffic. Was in MY Mode set to Sport. 2.8 seconds for both. Left foot on brake, right WOT while lifting left. Still don't have the 1500 miles to try launch control.
Then drove in Z-Mode Power set to Track. Accelerated rapidly and stopped aggressively (as I had done before) to put some heat in tires. Performed 0 to 60 test. Result 2.5 seconds. Dash looked the same so this is old pic.
Just some thoughts for those trying.
BTW: My cousin has a Porsche Carrara 4S. He was impressed when he was pinned to the seat!
I ran my 23 Z and the dashboard showed 2.6 my dragy showed 3.27 I would not bet on that dashboard being remotely close.
Using the test on the right center dash that is on my E-Ray and was NOT on my 2020 C8. Also Don't care about applying for a Guinness Book of Records, just comparing what I do to achieve the test numbers.
Did that when I turned my street rod 23 years ago with my G-Tech Pro that uses an accelerometer. Worked great in making the major changes to my 850 Holley Double Pumper on my 8.2 Liter BB. Also setting the instant center on my adjustable 4 bar link rear suspension. Also helped define with adjustable height on my rear coilovers to counter rear axle torque.
Still have the G-Tech pro but what bother to complicate the testing when I get simply by setting up the test on the dash! If GM is using the matrix of accelerometers, they use to control MRC, all the better. If they have roll out in the numbers, don't care. I post comparative numbers based on what I do to achieve. Not looking to break a record.
I ran my 23 Z and the dashboard showed 2.6 my dragy showed 3.27 I would not bet on that dashboard being remotely close.
I have been preaching this since I bought my 1st C8, but it falls on deaf ears.
My C8 Z51 always said 2.8, and that was on 3.3 0-60s according to my Dragy.
My C8 Z06 best on so far in cold weather, full tank of fuel, and high tire pressures of 36lbs my Dragy said 3.09, the PDR would probably have said 2.4, lol.
Originally Posted by 123sugey
Every single Z and E should come with a Dragy 😃
They should build it in to the car.
I will say, with AWD and no lag on launch the PDR might be a little more accurate compared to the Dragy. I think it may only be off by 0.2.
I can't see the E-ray being worse than 0-60 in 2.7-2.8 on unprepped streets and I definitely can see 2.5-2.6s on a great run.
Gotta love how some guys call BS on 0-60 in the lower 2's and spot on at 3.0 seconds. Hillarious. Denial and pre-conceptions are powerfull mental tools indeed.
I have been preaching this since I bought my 1st C8, but it falls on deaf ears.
My C8 Z51 always said 2.8, and that was on 3.3 0-60s according to my Dragy.
My C8 Z06 best on so far in cold weather, full tank of fuel, and high tire pressures of 36lbs my Dragy said 3.09, the PDR would probably have said 2.4, lol.
They should build it in to the car.
I will say, with AWD and no lag on launch the PDR might be a little more accurate compared to the Dragy. I think it may only be off by 0.2.
I can't see the E-ray being worse than 0-60 in 2.7-2.8 on unprepped streets and I definitely can see 2.5-2.6s on a great run.
Yeah, I am willing to bet a lot of cars are 2.9-3.1. in the real world.. including 9 sec Mclarens..
I've never called BS on anybody, just stating the proven fact that the PDR is not accurate.
Keep in mind I've probably owned more Vettes than most on this forum, it's not like I am not a fan of the Vette.
I just know every time my Dragy said anything over 3.19 in my previous C8 Z51, the PDR said 2.8.
That car was a consistent 3.3 0-60 car, yet the PDR always said 2.8.
I have never used the PDR in my C8Z, so far my best Dragy was a 3.09 in cold weather with full tank of fuel and high tire pressures over 36#.
Lower the tire pressure, run with less than 1/2 tank and warmer weather for stickier streets and I could see 2.8-2.9s easily, but I would not want to go from a dig vs the AWD E-ray. From a roll, different story, the Z is an absolute animal once it is hooked up and moving.
Keep in mind, I am a huge fan of the E-ray, love AWD for the street and consistently fast launches.
If I didn't have my Porsche 911 Turbo S which s AWD I would own an E-ray and my C8Z.
BTW, I've never had anybody call BS on my consistent 0-60 in 2.6s per my Dragy in my Porsche on unprepped street surfaces on all-season radials with a 560 treadwear rating.
The E-ray should be able to do that also as it has a bit more power than my Porsche, but weighs a bit more.
Yeah, I am willing to bet a lot of cars are 2.9-3.1. in the real world.. including 9 sec Mclarens..
I wouldn't want to attempt to beat a McLaren from a roll in anything, they are absolute beasts bone stock, I still wouldn't want one.
Once they release a C8 with the C8Z engine and AWD I will be in line.
04-05-2024, 06:47 AM
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