Speedo Correction for Larger Tires - Page 3

carringb · 02-14-2010, 12:22 AM

Quote:

Originally Posted by geoffff

Hmmm, thinking about the idea of the ABS sensor being used for speed -- I just read online a thought that makes sense to me: How can it be using the ABS sensor if the speedo is 4x (or whatever) off when the Atlas transfer case is in Low range (as it is on my van)?

If my van was really using the wheel ABS sensor, it should be unaffected by anything but wheel speed, right...?

-- Geoff

Means your van is taking off the tailshaft sensor. If you put a switch on the 4x4 shifter, you can connect to the 4x4-lo wire under the hood, and it will apply a correction factor for the NV T-cases. I think Atlas offers several lo-ratios, so your could be close.

Steve_382 · 02-14-2010, 11:09 AM

Looks like Hypertech also makes several different tuners and speedo correction tools. 4 Wheel Parts seems to carry a lot of different options also. I am in the market, but haven't decided yet. 4 Wheel Parts in my area recommended a Hypertech tuner that was supposed to increase HP and Torque as well as correct the speedo for about $350 or so.

http://www.4wheelparts.com/Electronics. ... =74&t_s=33

http://go.hypertech.com/products-max-energy.aspx

http://go.hypertech.com/products-speedo ... rator.aspx

Christopher Thwaites · 02-14-2010, 12:38 PM

Herb,
My calcs are by hand. I don't have a scan guage. Yet......!
Also, SCT 5star creates custom tunes from a 3 page questionair completed by the customer. For the basic cost of about $375 you get 3 custom tunes. From the sounds of other posts on tuners it seems most come pre-loaded with generic tunes. I might be uninformed but it makes sense to me that every van and driver are different so each tune should be taylored accordingly.

**BroncoHauler** · 02-14-2010, 12:52 PM

Thanks Chris. Yeah I know that most, if not all, SCTs are custom programmed. That's one reason it's my choice if I go with a tuner. I think this is especially important with a van. I think most tuner manufacturers don't care if you have an F series or an E series. I think given that vans have a challenge in getting rid of heat, it shouldn't be a one-size-fits-all solution between the pickups and the vans.

I think the hand calculation for mileage is important too.

Herb

cellularSTEVE · 02-14-2010, 01:27 PM

Quote:

Originally Posted by Christopher Thwaites

I'm half way through a 2500 mile trip and so far my avg. mpg has improved by 2 mpg. The tuner also corrected the speedo error for my larger tires.

Hey Chris,
I was just thinking. Could the 2mpg increase just be a perception since your speedometer/odometer were previously off, due to the larger tires?
steve

Christopher Thwaites · 02-14-2010, 03:24 PM

Steve,
Before I corrected the speedo error I always drove with my GPS on and used it to check mileage. I also checked the speedo against the GPS after the new tune was set. Since I only have a 30 gal. tank I have to pay attention on road trips when I'm not sure of the next availble gas. SCT made no warranty as to better mpg but the tech I worked with by phone said 1 to 2 mpg improvement would not be unusual. I also forgot to mention I stick to 60 mph or less on freeway so maybe that is a factor as well. I plan to keep track over time and different driving situations so stay "tuned" for further impressions.

luked · 08-18-2010, 04:31 PM

will any of these options work with my 2003 7.3 PSD?

Luke

carringb · 08-18-2010, 06:02 PM

Quote:

Originally Posted by luked

will any of these options work with my 2003 7.3 PSD?

Luke

I believe the 7.3L have a remote render, and a speedometer gear mounted on the transmissions. This gear can be swapped out for different ratios, and are a regular dealer stock item. At least 2000 PSD vans use that method. I'm sure about '03.

ANZAC · 09-15-2011, 09:42 PM

Has anyone used one of the 12 o'lock labs modules?

Any other options I should look at?

(edit) Hypertech has a programmer for $199 (I found it for $164....), that according to their web site, will program a 2002 V10 computer for different tire sizes...

Anyone try one?

SheepShagger · 09-16-2011, 09:53 AM

I put in a SCT tune not so long ago, when I deleted the EGR cooler as I didn't want the check engine light be on. It's given me about the same round town, ~17mpg, but on the freeway I'm up 3~4mpg. That's checked by hand and scangauge. I was in the 12's on the freeway, now I'm between 15 and 16mpg.

My local independent PSD shop recommendation was not to do custom tunes unless you have done modifications to the engine. These guys do some serious PSD engine work, so I do trust their knowledge.
Since I have no performance mods and have no intention of doing any, they recommend I stick with the stock SCT tunes for the van. BTW, The stock SCT tunes are different for the Truck, Van & Excursion, none are the same.

If you do a tuner, I'd recommend an EGT gauge, I also did boost gauge as I didn't believe SCT tune hadn't increased the boost pressure as there is so much more power. But they hadn't, I think they increase fuel pressure and set the boost to come on lower.