The 5.29 Mega Thread!!

Yep ECU doesn’t know the R&P. That’s why we are hitting cutoff at ~85 as opposed to 104mph. The ECU thinks the truck must be going 104 because it’s in 6th gear at 2600rpm. Because we changed gearing we hit it at a lower speed.

@JoeCOVA do you know what ECU version your on? Maybe this isn’t necessarily related to vintage but to ECU version. I am on A61.

@im2122 are you A60 or A61?

 

This is easy to prove with a scan tool that reads data parameters. Look at fuel cut status when hitting stated speeds. Until then, y'all just toying with each others emotions.

 

I’m on a61 with ovtune 1.05.1 Gearlock 91 Octane

I have a scanner app that ill use later.

 

I'm not on a tune. I'm stock.

I definitely can't speak to your trucks but I know my truck does not limit the speed because its at 2600 rpms in 6th gear. The would have made my trucks top speed 77 mph. My truck cruises all the time at higher rpms in 6th gear.

When I was in Utah I easily hit 90 on stock tires with 5.29s..

 

Got to get into the nittiust of the gritties!

 

Is it true the locker seal is not compatible with synthetic oil? Or is that only for the ARB air locker?

Edit: I got the Lucas 80w140 non-synthetic anyway since that has a lot of recommendations.

 

https://youtu.be/3tOG2xuYuig
https://youtu.be/YNQdskCSdV0

I made two screen recordings. The first video is 6th gear. Notice the two gauges at the top. The right is the accelerator pedal position, the left is the actual throttle position. Neither one goes to 100%, not sure why.

I was wrong about fuel cut off, the truck doesn’t cut fuel when it’s limiting speed, it limits the throttle position.

Notice when on the first one at the :06 mark the throttle is limited to 50% even though the pedal position is still max. Then when the truck is still speeding up(0:11) it shuts it all the way down to 24% until the truck speed goes down, then slowly ramping it back up. Notice I’m both videos the accelerator pedal position doesn’t change.

I posted two to show what the lower gears do, in 4th it allows the truck to almost read 90. As you can see the gps speed is significantly higher, so I’m not too concerned with the limitations, but it’s good to know when you’re overtaking someone.


You may notice in the second video, there is a point where both the vehicle speed and gps speed match, that is because I didn’t set the range high enough on the gps gauge. Notice it maxes at 90.

 

I have a set of used nitro 4.88s front and rear if anyones interested

 

I’m sure there are some people interested in the 4.88 thread.

 

Those videos are weird. It shows an increase in rpm when the throttle is pulled back. It also shows a massive spike in speed when you lift the accelerator position.

5.29 and 33s at 90 mph is 2800 rpm. That’s where you were cut off.
5.29 and 33s at 100 mph in 4th is 5300 rpm. That’s where you were cut off.

EDIT. My calculations were off but now corrected. So basically you are limited to 90 in 6th but in 4th can go to almost 100

Good info if anyone ever intends to race their truck.

I wonder now if it’s an Overdrive thing. Try a test in 5th

 

Best decision ever going with 5.29 at 1000+ lbs on a 3rd gen AT and on 285/75/17’s the before and after difference is HUGE!

 

It’s the upgrade you kick yourself for not doing sooner! Welcome to the club!!!

 

How many have changed from 4.88's to 5.29's ?

 

Better question is how many have changed from 5.29 to 4.88z

 

https://youtu.be/9DA2M3G7pqs

 

How much?

 

But they are 4.88!! Go big or go home!

 

No one has replied to my question about a second gen 6MT on 5.29’s yet

 

Most likely because this is in the third gen section.

 

They are for a 16+