11-02-2020, 04:24 PM | #43 | |
Drives: like an old lady Join Date: Jun 2012
Location: indiana
Posts: 2,394
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Quote:
i don't see the auto 1LE doing any better because of the gear ratio. maybe the tire.
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2016+ camaro: everyone’s first car
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11-03-2020, 07:55 AM | #44 | |
Drives: 2018 Camaro SS 1LE Join Date: Aug 2018
Location: Tampa Florida
Posts: 1,980
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Quote:
Yea that mph wasn't very impressive, I've gone a bit faster on 13 second runs lol.. could also be an error or issue with the track sensors, who knows.
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2000 Miata - aventi storm wheels, roll bar.
2019 Mustang GT pp1 - svt pp2 wheels, mbrp cat back, sync 3 upgrade, p1x procharger + stg2 intercooler. 2018 Colorado zr2 - zr2 sport bar, showcase spare tire. 2018 Camaro SS 1LE - GM cai, black bowties, suede knee bolsters, 1le plate frame, black fuel door, dark tails + 3rd brake light, euro side markers + led's, GM all weather floor mats, velossatech big mouth, GM strut brace. 2017 Corvette Grandsport (sold) - untouched. 2006 GTO (sold) - iat relocation, air box mod, monero side marker lights. |
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02-02-2021, 04:46 PM | #45 |
Drives: Red Hot 2017 Camaro SS A8 Join Date: Oct 2017
Location: Port St Lucie Florida
Posts: 41
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I got a 1.75 60 ft on a M/T ET Street S/S with just a K&N Blackwing Cold Air Intake & Ported Throttle Body 11.66@119.79
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02-02-2021, 05:29 PM | #46 |
Drives: 2021 LT1 10 speed auto Join Date: May 2013
Location: Connecticut
Posts: 2,343
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Super nice pass, congrats for sure. Running a 10 speed auto ? do you remember if the car stayed in 5th gear thru the traps? or did up upshift real close to the end of the 1/4?. Great MPH, car is making some horse power, what was the DA or what was the temp? Did you flat foot the car off idle or did you foot brake torque it up and then go? I am prepping my 2021 LT1 10 speed auto to get do at least a 11.80 pass, please understand my interest and thank you.
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02-04-2021, 03:44 PM | #47 |
Drives: C6 Vette Join Date: Jul 2008
Location: NC
Posts: 88
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I think you guys are bass-ackwards on your shift point thinking. If the car shifts by MPH from the rear wheels, then a taller rear tire will make your shift point (rpm) higher. A smaller tire will see more revolutions of the tire at a given MPH. So the car will THINK it’s doing 60mph when in fact it’s only doing 58 mph.
I just put a set of the 275 35 20 Nitto 555r2’s on my car yesterday. The stock LT1 with run flats says they are 27.77 inches diameter according to the tire spec. The 555r says it is 27.56. Pretty close so I went with it. The car shifts at 6300 rpm in full auto. I didn’t pay attention to where it shifted before I put the tires on but plan on switching back in order to check. My phone GPS shows the car to be off by 1 mph. The car will show 60mph when my phone GPS shows 59mph. Despite the measurements per the specs, here is a side by side of the stock 245 against the Nitto 275/35. I’ll tell you what the REAL measurements are in the next few days as I’m going to measure them. |
02-04-2021, 04:43 PM | #48 | |
Drives: 2021 LT1 10 speed auto Join Date: May 2013
Location: Connecticut
Posts: 2,343
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02-04-2021, 05:34 PM | #49 | |
Drives: Red Hot 2017 Camaro SS A8 Join Date: Oct 2017
Location: Port St Lucie Florida
Posts: 41
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Quote:
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02-04-2021, 05:49 PM | #50 |
Drives: 2021 LT1 10 speed auto Join Date: May 2013
Location: Connecticut
Posts: 2,343
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02-04-2021, 07:21 PM | #51 | |
Drives: C6 Vette Join Date: Jul 2008
Location: NC
Posts: 88
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Quote:
At least that’s my theory! |
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02-05-2021, 06:31 PM | #52 |
Drives: C6 Vette Join Date: Jul 2008
Location: NC
Posts: 88
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So I swapped the wheels back to stock and measured them. The Nitto 555R2 275/35/20 has a circumference of 86.875 / 3.147 that’s 27.60. The advertise 27.56 so pretty damn close! The stock run flat measured a circumference of 87.750 / 3.147 is 27.88 so pretty damn close to their specs too. Despite the optical illusion in the picture, they are in fact pretty close in size.
Then with the stock setup against my phone GPS the speedometer was off by the same as the DR’s and the shift points were pretty much the same too. Looks like we won’t know how tires change shift points until someone does similar experiments with tires more different in size vs stock. |
02-05-2021, 09:47 PM | #53 |
Drives: Red Hot 2017 Camaro SS A8 Join Date: Oct 2017
Location: Port St Lucie Florida
Posts: 41
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02-06-2021, 03:40 AM | #54 | |
Drives: 2016 Camaro 2SS Join Date: Apr 2017
Location: Stansbury Park, Utah
Posts: 1,087
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Quote:
I know this because I went to the track with shifting set at stock tire height, but at the track I switched to my 26" DR. I hit the limiter on my 1-2, 2-3, 3-4 shifts. Informed my tuner and 1st thing he said was "are you using a shorter tire?". He sent me a new tune with lower mph shift points.
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2016 2SS, MRC, NPP, A8. Procharger P-1X,Stage II,std bypass, 3.9, Alky Meth - 10.84 @129 - DA+2000
New Mods - GPI drop ins, Kooks 2", LT4 fueling, Cam, Circle D Converter, 3.5 pulley & dual nozzle meth. |
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02-06-2021, 07:42 AM | #55 | |
Drives: 2024 Toyota Camry XSE Join Date: Sep 2017
Location: South Texas
Posts: 155
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Quote:
Actually, the transmission shifts by MPH AND RPM. The shift is a two-step process that is MPH Initiated and RPM Completed. The shift tables require both parameters. I pay a lot of attention to shift points and log every run on the drag strip to tweak the tune shift points. The shift is initiated at the MPH number in tune (can vary 1 MPH) and completed at the RPM number in the tune (again this can vary by 50-75 RPM or more). Think of it as "nominal" 6500 RPM if that is the target. For example, my 2-3 shift will initiate at 45 MPH and complete at 6543 RPM (50 MPH). 3-4 shift initiates at 72 MPH, completes at 75 MPH and 4-5 shift initiates at 95 MPH, completes at 95 or 96 MPH. The 4-5 shift illustrates that the shift will not initiate until the target MPH is reached and if the RPM already exceeds the parameter in the tune the shift will complete almost immediately with only 33 RPMs between initiation and completion. As for tires, the computer looks at tire height (measured with tire on car sitting on ground) not diameter. There is a place in the tune for that number and it affects the transmission shift points and speedometer. IF you put a taller or shorter tire on the car and don't change that parameter in the tune it will not shift correctly, as grandpa_ss said. I don't want to question your tuner or you grandpa (and this could be just a matter of semantics), but I would not want lower shift points alone to fix the problem, I would also want the correct tire height parameter changed in the tune. Of course, that would mean one tune for your street tires and another one for the drag strip.
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2016 1SS - Bought: 8/2017 Sold: 12/2023
Last edited by Yosh6; 02-21-2021 at 06:18 AM. |
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02-06-2021, 07:58 AM | #56 |
Drives: 2022 Lt1 A10 Join Date: Nov 2015
Location: clark, mo
Posts: 8,857
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I run the 305-35-19 Nitto 555r2s and really like them for my power level. My best et with those are 11.18@125 w/1.63 60ft. Just a few simple mods, E85, Speed Engineering long tubes and not cats. My C7 consistently hooks every time and rarely see over a 1.67 60ft. I hope to do some tuning on the tranny and break into the 10s this spring. I may need to find a ported MSD if I can't do it with just tuning. I know my Vette is a couple hundred pounds lighter then the Camaro so that is worth a couple tenths. The 305 I run is bout 1/2" taller then the 285 so I don't see any advantage with a 10 speed of running a shorter tire then stock since the A10 has a lower 1st gear the my A8. Yosh6 is right on the shifting on the RPM and MPH, its critical to have those correct so it shifts on time and doesn't hit the rev limiter.
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2022 Lt1 6.2 A10, Maggie 2300, THPSI Port Inj/10 rib, Rotofab, E, Nickey, SCOL, Griptech, RC Bandits, Hoosiers/MT 9.80@142.96 1.44 60ft, 6.34@112 707/669 RWHP/TRQ. 16SS Maggie 2650 9.41@147 1.35 60ft, 5.99@119. 16 C7 A8 10.90@128 Bolt on stuff
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