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I’m doing research for the future, is that ok with you? Obviously I know more about tires than you do, so you’re welcome for the free education. I’ve also driven a C8Z07 on the race track and laid down a time that was a second off the ACR Viper’s track record on that track, so I recommend you get one if on the fence. Had it been my car and the owner not riding shotgun I think I could have matched it if given more than the few laps he graciously allowed me to take.
What led you to believe I was referring to you? As far as tires that is a matter of opinion, and you are entitled to yours. I appreciate the info you share though.
Last edited by Shinobi'sZ; 03-20-2024 at 06:33 PM.
What led you to believe I was referring to you? As far as tires that is a matter of opinion, and you are entitled to yours. I appreciate the info you share though.
Who were you talking about then? Tires can be subjective, but that’s why I posted the results and categorization by a national auto sport association as figure they’d carry more weight. The R888 isn’t a bad tire, it’s just not the go to tire for people who compete in my experience. Manufacturers are competing for bragging rights, so the 2R is what’s ran by Porsche, Ferrari, Mercedes and Chevrolet. My apologies for my initial reaction, the R888 is like the Nitto of the drag racing world imho. People who are serious about going fast run M/T or Hoosier.
Who were you talking about then? Tires can be subjective, but that’s why I posted the results and categorization by a national auto sport association as figure they’d carry more weight. The R888 isn’t a bad tire, it’s just not the go to tire for people who compete in my experience. Manufacturers are competing for bragging rights, so the 2R is what’s ran by Porsche, Ferrari, Mercedes and Chevrolet. My apologies for my initial reaction, the R888 is like the Nitto of the drag racing world imho. People who are serious about going fast run M/T or Hoosier.
The GT3RS has been wearing 2Rs since 2018 and believe was the first production car to use them as they’re the biggest reason for it’s dramatic drop in Ring times. Before the 2R the bespoke Kumho ACR Viper was the fastest production car tire imho, then the 3R on the ZLE Camaro would be next. https://www.motor1.com/reviews/24043...rst-drive/amp/
Who were you talking about then? Tires can be subjective, but that’s why I posted the results and categorization by a national auto sport association as figure they’d carry more weight. The R888 isn’t a bad tire, it’s just not the go to tire for people who compete in my experience. Manufacturers are competing for bragging rights, so the 2R is what’s ran by Porsche, Ferrari, Mercedes and Chevrolet. My apologies for my initial reaction, the R888 is like the Nitto of the drag racing world imho. People who are serious about going fast run M/T or Hoosier.
I think that's where we were getting wires crossed, I was mainly thinking of the R888 as a street/strip straight line performance tire that is still great for cornering, wasn't comparing the CUP2R vs. R888 on a track. For road course the best tire is clearly the CUP2 or CUP2R.
Last December bought my wife the Tesla X Plaid. The 1020 hp and instant torque is just crazy - no other way to describe it. 0-60 2.5 and quarter mile in under 10 seconds - from a family car that seats 6. So for future ERAY owners beware if you see a funny emblem on the back of a Tesla S or X. The X might be a good race, the S would probably just walk away.
Yep, I'll beware! But I made 2.5 seconds WITHOUT LAUNCH MODE! That was after my 500 mile brake-in but won't use launch mode until I have ~1500 miles! That matches what GM quotes but Jason Cammisa who MC's the Hagerty video where the E-Ray bested the Ferrari and Lambo in the quart showed 2.4 seconds.
I think that's where we were getting wires crossed, I was mainly thinking of the R888 as a street/strip straight line performance tire that is still great for cornering, wasn't comparing the CUP2R vs. R888 on a track. For road course the best tire is clearly the CUP2 or CUP2R.
I understand, but a tire that is fastest on a road course means it has the most grip as long as it’s up to the right temperature. Which GM knows that and is going to put their best foot forward if going through the trouble of testing it on an E-Ray as someone claimed happen.
Yep, I'll beware! But I made 2.5 seconds WITHOUT LAUNCH MODE! That was after my 500 mile brake-in but won't use launch mode until I have ~1500 miles! That matches what GM quotes but Jason Cammisa who MC's the Hagerty video where the E-Ray bested the Ferrari and Lambo in the quart showed 2.4 seconds.
No disrespect but the car timer is great for using as a reference but there not accurate. They use a roll out start and don't factor in incline/decline. There is a few posts on this forum that people tested it against dragy's and vbox's. The car timer was roughly around .3 low. There is a video floating around of a company testing the eray and they got 2.2 and 2.3 0-60 on the car timer which would make sense since this would equal chevy's claim of 2.5. I'm not sure how most of these places tests these cars, if they use a roll out 1' start or real start. I bet when you start using launch control you'll see the 2.2 or 2.3. This is the reason I passed on the z06 and waiting on my eray.
Yep, I'll beware! But I made 2.5 seconds WITHOUT LAUNCH MODE! That was after my 500 mile brake-in but won't use launch mode until I have ~1500 miles! That matches what GM quotes but Jason Cammisa who MC's the Hagerty video where the E-Ray bested the Ferrari and Lambo in the quart showed 2.4 seconds.
Not saying the E-Ray isn’t fast, but figure you’re on here enough Jerry that you know the on board timer isn’t always accurate. Regardless how much ET is the launch control worth do you think? Obviously the electric motors assist with instant propulsion and the LT2 has good low end torque along with fairly steep gearing. Has anyone done back to back testing with and w/o to see the difference? Imagine it’s 2-3 tenths
^^^
Well aware, more than most, see SIDEBAR!
Who cares about accurately I just do comparisons to see if what I am doing is an improvement! Not looking to get in a Guinness Book of records. As Einstein would say "It's All Relative!"
As long as it's consistent it's GM's system and good enough for that purpose. When I watched the Jason Cammisa MC'd Hagerty video 2.4 to 60 is what it showed on the E-Ray screen! (Note: That video was made with GM engineers and marketing folks present, how else would Hagerty get an E-Ray BEFORE there were any out! Also the video was professionally made NO HOME MOVIE like most Youtuber's. Bet GM wrote the Story Board and words. Cammissa is a Pro and delivered well.) The dash showed 2.4 to 60, which was GM's system. Also noted although they quote the E-Ray being faster it the 1/4 than the Z06 they tested they did NOT show a pic with E-Ray. They no doubt knew some folks/writers could take that clip and use it as a negative in articles! Yep half my career was in R&D the other marketing- do know the tricks! I post the one with the Ferrari and Lambo:
SIDEBAR Sorry, not trying to be an *** but when I post that pic see enough of these comments about accuracy that looked back at MS class courses! One in the MS in Mechanical Engineering there was one ME 218 on Instrumentation. Statistically there are errors in all measurements and they stack up. In welding, my field, we're terrible for measuring volts and amps as when using high current, like the ~3000 amp system I developed that made a two pass SAW in the long seam in much of high pressure gas and oil pipe in the ground today. The magnetic field around the large welding current carrying cables induced errors on the meter reading wires!
See in my Management Masters ME 304 Advanced Analytical Statistics. Yep lots of measurement methods, all have some error. The key is consistence and repeatability. "It is what it is" and if constant it's great for my purposes. Better that the G-Tech Pro (based on an accelerometer) I used 23 years ago when making many measurements 0 to 60 in my Street Rod as I fixed the bog! The relative numbers are all that matters!
No disrespect but the car timer is great for using as a reference but there not accurate. They use a roll out start and don't factor in incline/decline. There is a few posts on this forum that people tested it against dragy's and vbox's. The car timer was roughly around .3 low. There is a video floating around of a company testing the eray and they got 2.2 and 2.3 0-60 on the car timer which would make sense since this would equal chevy's claim of 2.5. I'm not sure how most of these places tests these cars, if they use a roll out 1' start or real start. I bet when you start using launch control you'll see the 2.2 or 2.3. This is the reason I passed on the z06 and waiting on my eray.
Originally Posted by PRE-Z06
... the on board timer isn’t always accurate.
^ This
It's notoriously inaccurate as reported by many here on the forum who have done comparative tests...
It's notoriously inaccurate as reported by many here on the forum who have done comparative tests...
It's ONLY important relative to the next measurement!
Did you know the International Standard for the Meter is no longer a physical item kept in Paris! Nope, quoting:
The metre, symbol m, is the SI unit of length. It is defined by taking the fixed numerical value of the speed of light in vacuum c to be 299 792 458 when expressed in the unit m s–1, where the second is defined in terms of the caesium frequency ΔνCs.
SIDEBAR
And recently they have argued since even more accurate methods are being developed each country can use their own more accurate method! Yep the SI folks have just finally defined the teaspoon that has been different across Europe! Not affecting my field but medicine! Yep been a member of our society Metric Practice Committee since it started in the mid 1970's (we have an ANSI approved Publication as well.) Been Chair for >10 years (can't find anyone who wants to take over!)
Great book on the subject, called "The Measure of Things," that quotes George Washington's Inaugural Address that said we MUST change our currency (at the time. British pounds, Ditch Guilders, Spanish Doubloons, etcwere all in use) AND measurement system. Ben Franklin and Adams (who owned or were affiliated with banks) also pushed for the base 10 Metric Measurement System being accepted in France. Typical of Congress they only installed our base 10 money system and did nothing with our foot, yard, foolish need for fractions based system! Yep follow the money!
^^^
Well aware, more than most, see SIDEBAR!
Who cares about accurately I just do comparisons to see if what I am doing is an improvement! Not looking to get in a Guinness Book of records. As Einstein would say "It's All Relative!"
As long as it's consistent it's GM's system and good enough for that purpose. When I watched the Jason Cammisa MC'd Hagerty video 2.4 to 60 is what it showed on the E-Ray screen! (Note: That video was made with GM engineers and marketing folks present, how else would Hagerty get an E-Ray BEFORE there were any out! Also the video was professionally made NO HOME MOVIE like most Youtuber's. Bet GM wrote the Story Board and words. Cammissa is a Pro and delivered well.) The dash showed 2.4 to 60, which was GM's system. Also noted although they quote the E-Ray being faster it the 1/4 than the Z06 they tested they did NOT show a pic with E-Ray. They no doubt knew some folks/writers could take that clip and use it as a negative in articles! Yep half my career was in R&D the other marketing- do know the tricks! I post the one with the Ferrari and Lambo:
SIDEBAR Sorry, not trying to be an *** but when I post that pic see enough of these comments about accuracy that looked back at MS class courses! One in the MS in Mechanical Engineering there was one ME 218 on Instrumentation. Statistically there are errors in all measurements and they stack up. In welding, my field, we're terrible for measuring volts and amps as when using high current, like the ~3000 amp system I developed that made a two pass SAW in the long seam in much of high pressure gas and oil pipe in the ground today. The magnetic field around the large welding current carrying cables induced errors on the meter reading wires!
See in my Management Masters ME 304 Advanced Analytical Statistics. Yep lots of measurement methods, all have some error. The key is consistence and repeatability. "It is what it is" and if constant it's great for my purposes. Better that the G-Tech Pro (based on an accelerometer) I used 23 years ago when making many measurements 0 to 60 in my Street Rod as I fixed the bog! The relative numbers are all that matters!
It’s inconsistent is maybe a better way to put it, so comparing results aren’t relative. What starts the timer exactly? GPS movement, wheel speed or a combination? The GPS signal and tire spin are the two variables that I believe cause the issue, though someone can correct me if I’m wrong.
It’s inconsistent is maybe a better way to put it, so comparing results aren’t relative. What starts the timer exactly? GPS movement, wheel speed or a combination? The GPS signal and tire spin are the two variables that I believe cause the issue, though someone can correct me if I’m wrong.
The GM system is probably very consistent. It's computer based and IF biased it is the same each time out many significant figures.
I have fun answering these questions as obviously some would like to not believe the E-Ray is faster than say the C8 Z06 to 60 (and probably the quarter as several have published!)
As I have said, have driven many fast cars, like my friend and colleague's 1967 425 hp, 454 Vette. Although it was exciting (had side pipes and made lot's of noise) fighting the flexible chassis torque steer, those 205 section width tires are quoted as only going 0 to 60 in 5 seconds. Think I did better as I slipped the clutch significantly to maintain launch traction BUT nowhere near the E-Ray's 2.5 +/- whatever folks want to put on the error. Yep the '67 was exciting, lots of trauma. Little trauma with the E-Ray as I expect the 2.4 (or better) I'll achieve in Launch Mode.
And that is NOT on a prepared Track as when I was on the Lauch pad with Tom Hammon in his ProStock car at a National Event at the Charlotte Motor Speedway a few years ago. I was tightening a Duez fastener on the body as Tom requested and almost tripped as forgot the start line is so sticky you must lift each foot straight up, can't slide!
Yep my 2.5 was on pavement starting in the center of the two-lane road so it's camber did not affect tire angle!
I understand, but a tire that is fastest on a road course means it has the most grip as long as it’s up to the right temperature. Which GM knows that and is going to put their best foot forward if going through the trouble of testing it on an E-Ray as someone claimed happen.
I should have clarified that when I was referencing R888, I was referring to the R888R as I thought they replaced or superseded the R888. I run R888R 345/30 19's on back of my C7Z. I get very good traction with them at 700whp. The dragstrip near me closed permanently in December, but luckily there is a dragstrip that operates with a tree a few times a year at a local airstrip a few times a year close. Looking forward to trying them out soon on a strip.
The GM system is probably very consistent. It's computer based and IF biased it is the same each time out many significant figures.
I have fun answering these questions as obviously some would like to not believe the E-Ray is faster than say the C8 Z06 to 60 (and probably the quarter as several have published!)
As I have said, have driven many fast cars, like my friend and colleague's 1967 425 hp, 454 Vette. Although it was exciting (had side pipes and made lot's of noise) fighting the flexible chassis torque steer, those 205 section width tires are quoted as only going 0 to 60 in 5 seconds. Think I did better as I slipped the clutch significantly to maintain launch traction BUT nowhere near the E-Ray's 2.5 +/- whatever folks want to put on the error. Yep the '67 was exciting, lots of trauma. Little trauma with the E-Ray as I expect the 2.4 (or better) I'll achieve in Launch Mode.
And that is NOT on a prepared Track as when I was on the Lauch pad with Tom Hammon in his ProStock car at a National Event at the Charlotte Motor Speedway a few years ago. I was tightening a Duez fastener on the body as Tom requested and almost tripped as forgot the start line is so sticky you must lift each foot straight up, can't slide!
Yep my 2.5 was on pavement starting in the center of the two-lane road so it's camber did not affect tire angle!
How do you know that it’s the same? Is the cell signal the same if it uses GPS distance to start as that accuracy can vary? If it uses wheel speed to start is that always the same? FWIW I did high 2s in my manual NA stock bottom end C5 back in the day before getting into road racing. Can’t tell the difference in a 1.4 60’ it did and the 1.5 60’ my C6GS when I took it to the drag strip for fun as it’s pulling 1G acceleration. Same on the road course, it’s hard to feel an extra tenth of G in a corner imho. It’s easier to sense you went a little faster visually or by the sound of the engine.
Originally Posted by Shinobi'sZ
I should have clarified that when I was referencing R888, I was referring to the R888R as I thought they replaced or superseded the R888. I run R888R 345/30 19's on back of my C7Z. I get very good traction with them at 700whp. The dragstrip near me closed permanently in December, but luckily there is a dragstrip that operates with a tree a few times a year at a local airstrip a few times a year close. Looking forward to trying them out soon on a strip.
I don’t know the difference in the R888 and R888R, but the results I posted were the latter and it still wasn’t very fast compared to more modern rubber used by OE cars. If it had a softer sidewall I could see that helping the launch, but I didn’t think it was a drag radial. I’ve wondered how much of a difference in compound there is in the Hoosier drag radial and Hoosier A7 as imagine it’s more about sidewall construction for lateral forces instead of just longitudinal.
How do you know what folks think is better is more accurate. Do they have the military satellite positioning accuracy? How would you know?
Frankly thought my G-Tech Pro, that uses an accelerometer was very consistent. After a lot of work and changes to the Holley Double Pumper carb was able to eliminate the slight bog at launch in my 8.2 Liter engine 53% rear weight street rod!
When I first tried three times in a row I got the same 2.7 seconds. No decimals after as they don't pretend more accuracy than it probably is! Yep that was the same as Tim McGaw lasted on a Bull names Fu Man Chu!
Is it as accurate as timing lights in a drag strip? Probably not! But when I saw, as I have validated even yesterday, when in Z-Mode the battery charges to close to 100% versus only ~80% when I made those first tests. that could be the reason. Was that the reason I got to 2.5 seconds. For what I'm doing good enough. No prize for getting accuracy to hundreds!
I don’t know the difference in the R888 and R888R, but the results I posted were the latter and it still wasn’t very fast compared to more modern rubber used by OE cars. If it had a softer sidewall I could see that helping the launch, but I didn’t think it was a drag radial. I’ve wondered how much of a difference in compound there is in the Hoosier drag radial and Hoosier A7 as imagine it’s more about sidewall construction for lateral forces instead of just longitudinal.
The A7s look good and come in a 345/30 19 as well, but they also caveat that they are DOT for marking and Not For Highway Use, the R888R states recommended for competition. From a tort liability perspective that's not the same language as "Not for highway use". Also the R888R has siping that makes them much better if encountering a wet surface, something I try to avoid in my sports cars or motorcycles, but still an added benefit.
How do you know what folks think is better is more accurate. Do they have the military satellite positioning accuracy? How would you know?
Frankly thought my G-Tech Pro, that uses an accelerometer was very consistent. After a lot of work and changes to the Holley Double Pumper carb was able to eliminate the slight bog at launch in my 8.2 Liter engine 53% rear weight street rod!
When I first tried three times in a row I got the same 2.7 seconds. No decimals after as they don't pretend more accuracy than it probably is! Yep that was the same as Tim McGaw lasted on a Bull names Fu Man Chu!
Is it as accurate as timing lights in a drag strip? Probably not! But when I saw, as I have validated even yesterday, when in Z-Mode the battery charges to close to 100% versus only ~80% when I made those first tests. that could be the reason. Was that the reason I got to 2.5 seconds. For what I'm doing good enough. No prize for getting accuracy to hundreds!
I’m not talking hundredths that it’s off, it’s been shown to be multiple tenths off. Vbox and Dragy have shown more consistency than the timer in car, my AIM that I use for road racing I believe is more accurate when I’ve used it to compare times at the drag strip. I was hoping you could tell me why that’s the case with GM’s timer as I’ve asked multiple times and yet to get an answer.
The A7s look good and come in a 345/30 19 as well, but they also caveat that they are DOT for marking and Not For Highway Use, the R888R states recommended for competition. From a tort liability perspective that's not the same language as "Not for highway use". Also the R888R has siping that makes them much better if encountering a wet surface, something I try to avoid in my sports cars or motorcycles, but still an added benefit.
The R888R does have more grooves than the Hoosier, but not a tire I’d want to run in the rain personally. One reason I like the C6 over the C7 is the ability to carry 2 tires in the back hatch…
03-20-2024, 06:26 PM
Sorry, not trying to be an *** but when I post that pic see enough of these comments about accuracy that looked back at MS class courses! One in the MS in Mechanical Engineering there was one ME 218 on Instrumentation. Statistically there are errors in all measurements and they stack up. In welding, my field, we're terrible for measuring volts and amps as when using high current, like the ~3000 amp system I developed that made a two pass SAW in the long seam in much of high pressure gas and oil pipe in the ground today. The magnetic field around the large welding current carrying cables induced errors on the meter reading wires!
