Easy Speedometer Calibration with HP Tuners

[@charliecorrell2161]

I know your video is a few years old. But thank you for your time and info man! i dialed my truck right in and it has a funky setup. 40" tires and 5.13 gears. got it perfect now

[@bluecollarhotrods9781]

I recently changed the gears in my Silverado. I have HP Tuners, but i am no tuner by any stretch of the imagination. I did what I thought would fix my speedometer Saturday morning... nope! Your video helped me figure out why, and how to fix it. Thank you! You have earned a new subscriber.

[@justintc93]

Glad I could help

[@bluecollarhotrods9781]

@@justintc93 Now I just need to get a wideband and figure out actual tuning... fuel and spark tables. I grasp the concepts of target a/f and timing. I just need to know how to apply that.

[@justintc93]

@@bluecollarhotrods9781 there is a lot of good content out there, and a lot of bad. I find most of the KZbin instruction to develop for habits for people. I would recommend doing a good bit of searching around on the HP tuners forum. They're is a lot of stuff even from 10 to 15 years ago that is still very relevant and very helpful

[@bluecollarhotrods9781]

@@justintc93 Thank you, looks like I have a lot of reading to do. I come from a background of EPROM tuning in the 2000s. I hadn't attempted any type of tuning since then and a lot has changed. The TBI/TPI stuff is much simpler and archaic.

[@DillZilla923]

Awesome video, was getting so frustrated not being able to get my speedo dialed in. Now it's perfect!

[@solo3071]

Greetings from New Zealand. Thanks so much for this video. Ive got 2 C5's 1 race and one street and the gears have been changed in both, 3.73 and 4.10. I have just calibrated the speedos and now both are shifting under WOT which wasnt happening before. which was very frustrating, I even tried adjusting the WOT RPM values and the speed values too, it didnt work. There are lots of threads on the forums saying you need to calibrate the speedo but you are the only one actually showing us how to do that. I was just about to enlist the help of a tuner. thanks again.

[@justintc93]

Glad I could help!

[@pcmfrenzy1089]

This was a good video. Learn something new everyday. The GM cluster stepper motors are junk. You want a video to make, I got one you can make. People are taking the 5.3/6.0 and putting them into the 80's square body trucks. They are using the stock 208 transfer cases, then using the Dakota Digital 8k sensors for VSS pickup to shift the 60e/80e transmission. Setting this up can be a real pain. Been using Blue Cats to help along the way. No body has this video yet.

[@justintc93]

I typicall try and stay away from swap stuff honestly unless it's simple and straightforward stuff I'm not a huge electrical guru.

[@michaelhodges9951]

Thanks very helpful!

[@matthewjeschke]

I have a problem with this... My PCM reports correct speed when I observe it with a scan tool. However, the speedometer reads wrong speed. The speedometer needle is 15% off. So I'm not sure about calibrating in PCM as it already has the correct speed... Is there a calibration for JUST the speedometer needle itself?

[@scubastevoo8404]

You probably have a bad stepper motor in the gauge . It will stop working altogether soon like mine did.

[@MrRoyalfelix]

Great info helped alot thanks

[@oscargasca6469]

So I’m going to put 4.56 gears on a 04’ avalanche and it has 35 inch tires do I put that information on the wizard and then do those changes you did

[@mrmidnight32]

Does this function require a license? I used my license on my 85 c10 with an LS swap. But bumped to 35’s on my 2015 Silverado and need to do a speedo correction and was hoping it would be free.

[@justintc93]

GM requires edits in the calibration and writing to the ECM which does require a license.

[@mrmidnight32]

@@justintc93 thanks!

[@dutywilliam]

Which Version of software/Tunner are you using. I know it’s hp. Just looking at which one to buy?

[@justintc93]

I always stay up to day on latest software release download from the website. MPVI2 is the only hardware option. Credits and pro features can be added at any time later on. I'm a dealer for HP Tuners if you're interested.

[@factoryspeed6786]

if you take your observed and divide it by your true you skip atleast 3 steps of this

[@justintc93]

It's not skipping 3 steps, it's doing almost the same thing as calculating the percent error and applying it, just not quite as precise.

[@factoryspeed6786]

@@justintc93 it actually is just as precise and you don't have to do nearly as much math

[@anthonywiseman1403]

I'm confused on the correct math for this. My speedo and scanner read 82ish while I'm going 40mph. I tried to do it identical to this but my numbers and that makes it way worse

[@justintc93]

Try going the opposite way

[@austinanderson7636]

Did this got the speedo on but when running wot when it goes from 2nd to 3rd it just hits rev shift back an does it again until I let out

[@justintc93]

Sounds like you need to adjust your shift mph setpoints

[@DanMcD80]

What about when the vss pulses per mile reads 7mph slower at the pcm when speedo reads correct?

[@justintc93]

Doing to depend on the pcm and operating system. Its also not uncommon to see the scanner averaging multiple readings, or the needle in the cluster actually be off some as well.

[@darinr9424]

how about just do the math on tire size ( tire roll out) to get the actual tire size and gear ratio to properly setup the speedo calibration. gps has accuracy issues.

[@justintc93]

It usually will get you very close, but not always dead on. Also some tires will grow more than others on the highway that rollout measurement won't quite get. If you're already driving the car for logging, a quick check with GPS will get you dead on in 1 change the vast majority of the time.

[@darinr9424]

@@justintc93 yep. roll out with the tire on the car to account for squish. not just measured unmounted.

[@deathbeforestock4426]

I will pay you to take a look at my tune

[@justintc93]

Any specific issues you're having you want looked at?