Correct Speed
Thread Starter
On The Tree
Joined: Nov 2003
Posts: 175
Likes: 0
From: Pacific Beach/San Diego/US Navy,LSCM
Correct Speed Right now I have 255X45Zx17 inch with 4:10 gear and my speed reads 75 at 1800 RPM'S // 70 1600 with 26.1 set in the PCM.
Does this sound right?
Any input would we greatly appreciated
Thanks in advance
Bruce/StoreKeeper99Z28
Does this sound right?
Any input would we greatly appreciated
Thanks in advance
Bruce/StoreKeeper99Z28
It looks a little off, even when I put in the correct tire height 1800 was 68, 1700 was 64, and 1600 was 60. Your tire height should be about 26.035 but I know it varies by tire brand and type and of course they wear down over time so that is dynamic as well.
Did you look here http://www.f-body.org/gears/
Did you look here http://www.f-body.org/gears/
This is with 4.10 gears and your tire size so yes it seems a little off. I've used this calculator for my manual transmission and it worked pretty well. A mile or two off when compared to GPS was all but that was probably just tach and speedo that were off. Hope this helps, go to the link I posted so you can play around with the ratios for yourself.
RPM 1st Gear 2nd Gear 3rd Gear 4th Gear 5th Gear 6th Gear
500 4 5 7 9 13 19
600 4 6 9 11 15 23
700 5 7 10 13 18 26
800 6 8 12 15 20 30
900 6 10 13 17 23 34
1000 7 11 15 19 26 38
1100 8 12 16 21 28 42
1200 9 13 17 23 31 45
1300 9 14 19 25 33 49
1400 10 15 20 26 36 53
1500 11 16 22 28 38 57
1600 11 17 23 30 41 60
1700 12 18 25 32 43 64
1800 13 19 26 34 46 68
1900 13 20 28 36 49 72
2000 14 21 29 38 51 76
2100 15 22 31 40 54 79
2200 16 23 32 42 56 83
2300 16 24 33 43 59 87
2400 17 25 35 45 61 91
2500 18 27 36 47 64 94
RPM 1st Gear 2nd Gear 3rd Gear 4th Gear 5th Gear 6th Gear
500 4 5 7 9 13 19
600 4 6 9 11 15 23
700 5 7 10 13 18 26
800 6 8 12 15 20 30
900 6 10 13 17 23 34
1000 7 11 15 19 26 38
1100 8 12 16 21 28 42
1200 9 13 17 23 31 45
1300 9 14 19 25 33 49
1400 10 15 20 26 36 53
1500 11 16 22 28 38 57
1600 11 17 23 30 41 60
1700 12 18 25 32 43 64
1800 13 19 26 34 46 68
1900 13 20 28 36 49 72
2000 14 21 29 38 51 76
2100 15 22 31 40 54 79
2200 16 23 32 42 56 83
2300 16 24 33 43 59 87
2400 17 25 35 45 61 91
2500 18 27 36 47 64 94
You really need to compare it to a GPS or radar.
You can change the numbers, tires, etc all you want and the speedo and tach will read as any calculator says it should. Problem is you have no idea how fast you're actually going.
And for factory tire size, using HP Tuners and the factory programmed stock tire size, the closest I could come to compare to their programmed size was by doing a rollout measurement on the tire.
You can change the numbers, tires, etc all you want and the speedo and tach will read as any calculator says it should. Problem is you have no idea how fast you're actually going.
And for factory tire size, using HP Tuners and the factory programmed stock tire size, the closest I could come to compare to their programmed size was by doing a rollout measurement on the tire.
Teching In
Joined: Dec 2008
Posts: 48
Likes: 0
RPM 1st Gear 2nd Gear 3rd Gear 4th Gear 5th Gear 6th Gear
500 4 5 7 9 13 19
600 4 6 9 11 15 23
700 5 7 10 13 18 26
800 6 8 12 15 20 30
900 6 10 13 17 23 34
1000 7 11 15 19 26 38
1100 8 12 16 21 28 42
1200 9 13 17 23 31 45
1300 9 14 19 25 33 49
1400 10 15 20 26 36 53
1500 11 16 22 28 38 57
1600 11 17 23 30 41 60
1700 12 18 25 32 43 64
1800 13 19 26 34 46 68
1900 13 20 28 36 49 72
2000 14 21 29 38 51 76
2100 15 22 31 40 54 79
2200 16 23 32 42 56 83
2300 16 24 33 43 59 87
2400 17 25 35 45 61 91
2500 18 27 36 47 64 94
chris
500 4 5 7 9 13 19
600 4 6 9 11 15 23
700 5 7 10 13 18 26
800 6 8 12 15 20 30
900 6 10 13 17 23 34
1000 7 11 15 19 26 38
1100 8 12 16 21 28 42
1200 9 13 17 23 31 45
1300 9 14 19 25 33 49
1400 10 15 20 26 36 53
1500 11 16 22 28 38 57
1600 11 17 23 30 41 60
1700 12 18 25 32 43 64
1800 13 19 26 34 46 68
1900 13 20 28 36 49 72
2000 14 21 29 38 51 76
2100 15 22 31 40 54 79
2200 16 23 32 42 56 83
2300 16 24 33 43 59 87
2400 17 25 35 45 61 91
2500 18 27 36 47 64 94
chris
RPM 1st Gear 2nd Gear 3rd Gear 4th Gear 5th Gear 6th Gear
500 4 5 7 9 13 19
600 4 6 9 11 15 23
700 5 7 10 13 18 26
800 6 8 12 15 20 30
900 6 10 13 17 23 34
1000 7 11 15 19 26 38
1100 8 12 16 21 28 42
1200 9 13 17 23 31 45
1300 9 14 19 25 33 49
1400 10 15 20 26 36 53
1500 11 16 22 28 38 57
1600 11 17 23 30 41 60
1700 12 18 25 32 43 64
1800 13 19 26 34 46 68
1900 13 20 28 36 49 72
2000 14 21 29 38 51 76
2100 15 22 31 40 54 79
2200 16 23 32 42 56 83
2300 16 24 33 43 59 87
2400 17 25 35 45 61 91
2500 18 27 36 47 64 94
chris
500 4 5 7 9 13 19
600 4 6 9 11 15 23
700 5 7 10 13 18 26
800 6 8 12 15 20 30
900 6 10 13 17 23 34
1000 7 11 15 19 26 38
1100 8 12 16 21 28 42
1200 9 13 17 23 31 45
1300 9 14 19 25 33 49
1400 10 15 20 26 36 53
1500 11 16 22 28 38 57
1600 11 17 23 30 41 60
1700 12 18 25 32 43 64
1800 13 19 26 34 46 68
1900 13 20 28 36 49 72
2000 14 21 29 38 51 76
2100 15 22 31 40 54 79
2200 16 23 32 42 56 83
2300 16 24 33 43 59 87
2400 17 25 35 45 61 91
2500 18 27 36 47 64 94
chris
Keep posting like that and you'll be up to 50 posts in no time!
Trending Topics
Thread Starter
On The Tree
Joined: Nov 2003
Posts: 175
Likes: 0
From: Pacific Beach/San Diego/US Navy,LSCM
took it out for a run
(4:10's) 255X45ZX17
80 MPH = 1950RPM
85MPH = 2100 RPM
It seems I'm off about 6 MPH at 2100 RPM
Mine is a M6.
Falkin ZIEX /ZE512 the Falkin rep said 26.1 to set the PCM at some other location say 26.4
Hope to get tis resolved.
You people are great !!
Rx Bruce
(4:10's) 255X45ZX17
80 MPH = 1950RPM
85MPH = 2100 RPM
It seems I'm off about 6 MPH at 2100 RPM
Mine is a M6.
Falkin ZIEX /ZE512 the Falkin rep said 26.1 to set the PCM at some other location say 26.4
Hope to get tis resolved.
You people are great !!
Rx Bruce
This is with 4.10 gears and your tire size so yes it seems a little off. I've used this calculator for my manual transmission and it worked pretty well. A mile or two off when compared to GPS was all but that was probably just tach and speedo that were off. Hope this helps, go to the link I posted so you can play around with the ratios for yourself.
RPM 1st Gear 2nd Gear 3rd Gear 4th Gear 5th Gear 6th Gear
500 4 5 7 9 13 19
600 4 6 9 11 15 23
700 5 7 10 13 18 26
800 6 8 12 15 20 30
900 6 10 13 17 23 34
1000 7 11 15 19 26 38
1100 8 12 16 21 28 42
1200 9 13 17 23 31 45
1300 9 14 19 25 33 49
1400 10 15 20 26 36 53
1500 11 16 22 28 38 57
1600 11 17 23 30 41 60
1700 12 18 25 32 43 64
1800 13 19 26 34 46 68
1900 13 20 28 36 49 72
2000 14 21 29 38 51 76
2100 15 22 31 40 54 79
2200 16 23 32 42 56 83
2300 16 24 33 43 59 87
2400 17 25 35 45 61 91
2500 18 27 36 47 64 94
RPM 1st Gear 2nd Gear 3rd Gear 4th Gear 5th Gear 6th Gear
500 4 5 7 9 13 19
600 4 6 9 11 15 23
700 5 7 10 13 18 26
800 6 8 12 15 20 30
900 6 10 13 17 23 34
1000 7 11 15 19 26 38
1100 8 12 16 21 28 42
1200 9 13 17 23 31 45
1300 9 14 19 25 33 49
1400 10 15 20 26 36 53
1500 11 16 22 28 38 57
1600 11 17 23 30 41 60
1700 12 18 25 32 43 64
1800 13 19 26 34 46 68
1900 13 20 28 36 49 72
2000 14 21 29 38 51 76
2100 15 22 31 40 54 79
2200 16 23 32 42 56 83
2300 16 24 33 43 59 87
2400 17 25 35 45 61 91
2500 18 27 36 47 64 94
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Verdad Gallardo With those things you can do a rollout test on your tires and put that number in your pcm. Your pcm is reading rollout of the tire, it's not talking to the rep on the phone, it doesn't care about diameter or circumference.
