Real World Info for guys thinking about 4.30's

There's not as much info out there on guys running 4.30's as there is for 4.56's and 4.88's, so thought I'd share.

Took my first ride on the interstate with 4.30's and here are results/first impressions.

My tires measure 34.5" and each tire and wheel combined is right under 100lbs each. (heavy combo, so take that into consideration)

For sure solved the transmission shifting problem. No more struggling to get to overdrive, then kicking in and out, etc. It's not over responsive, like 4.56's or 4.88's, feels more like what it actually is now, a 'stock geared' truck hauling an extra few hundred pounds. Doing the math, 4.30 with this size tires puts me as close to stock ratio as available.

When dash speedometer reads 61-62MPH, the RPM's are at about 2100. With 34.5" tires, GPS speedometer reads 70MPH

When speedometer reads 70-71MPH, the RPM's read about 2400. With 34.5" tires, GPS speedometer reads 80MPH.


Hopefully this info can help you guys out some when making your decision on gears. I know some folks have expressed concerns about high RPM's on the highway with 4.56's or 4.88's.

 

Thank you for the information.

That wide of a delta between indicated and actual speed concerns me. Personally, I would correct that.

 

You can't... I mean you can fake it, but can't fix it. To me, that's one of the single worst things about Tacoma's

 

I thought speedo-healers and Toyota software can do it. I can't think of the actual name. Too tired. Maybe HP Tuners.

 

I did all the math, if you could reprogram the ECU, right Now I'd be right under 10% over geared. If ECU could be recalibrated, I'd get better than OEM gas mileage

That's a downside to these trucks, on previous builds, you could regear and the transmission would report to the computer that everything is OK, run normal, you can't do that on these. The ECU always operates like you run 265/65/17 or other OEM 30.5" tire.

 

You can trick the dash speedometer, not the ECU. In other words, you can make the dash read close to right, but the ECU won't change fuel/air mixture or AT shifting.

 

Cool. Thanks for the info.

Stock 5th gear rpm at 70 should be around 2075 for anyone else looking to compare.

Auto right? Cause mine is and the 62/63 indicated is 70mph gps as well so id imagine you are.

Why bother. Shows less mileage on the truck

 

Bro, what's really concerning is that all our trucks dash speedometers are off from the factory. Mine was 1.5MPH at 70MPH according to GPS speedometer. Doesn't sound like a big deal.... Until you have a major failure just a couple hundred miles out of warranty! this didn't happen to me, but let's suppose....

My speedometer from the factory, like yours and everyone else's is off. Mine was about 1%. With 70,000 mile warranty, my warranty ran out according to the dash odometer 700+ miles too soon! Follow

 

Bro, what's really concerning is that all our trucks dash speedometers are off from the factory. Mine was 1.5MPH at 70MPH according to GPS speedometer. Doesn't sound like a big deal.... Until you have a major failure just a couple hundred miles out of warranty! this didn't happen to me, but let's suppose....

My speedometer from the factory, like yours and everyone else's is off. Mine was about 1%. With 70,000 mile warranty, my warranty ran out according to the dash odometer 700+ miles too soon! Follow

I dug up my on paper calculations for comparison.

 

Why bother... Better fuel/air mixture and AT shifting, better performance....

Problem is it can't be done

 

I meant fixing the dash itself.

 

now time to invest in hyper-tech speedometer calibrator.
https://www.amazon.com/gp/product/B001G9AMES/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

All that does is fix the clock.

Folks have tried those, all it does is make the speedometer read closer to normal. Doesn't affect performance. I'll give it a shot, I'll contact them and see what they say as far as my purchase vs impact on performance. If the math doesn't add up, do I get my money back?

Anyway, back on track, just wanted to share some real world info on 4.30's.

 

I just installed one of these this weekend. Couldn’t stand the speedo and trip odometer being so far off. Plus I didn’t want to explain to someone else driving the vehicle that the speedo was off 10%

 

My issue is, all it does is it fixes the display. It doesn't recalibrate how the truck systems run. In other words, it shows your friend who is driving, his real speed, but doesn't tell the truck to adjust fuel/air mixture OR shifting as if your running at that speed. Follow?

Example. I put 5.13's in a bronco II running 35's. That set everything back to OEM performance because the truck thought it was running 28" tires again at normal RPM's. The gearing took up the slack.

With 2nd gen, that doesn't happen. You regear, but the truck still sees and runs like you have bigger, heavier tires. What hypertechypertec does is change the reading on your speedometer. Like a camera trick. Follow?

 

Not exactly. I’m not sure why gearing would have any real effect on you commanded a/f ratio. I thought that the commanded values were more predicated on throttle position, load and other variables that are fed back with sensors. Transmission performance is controlled by other tables as well. Or at least I thought? What are your concerns about gears effecting you a/f ratio?

 

If the ABS sensors are telling the ecu that you are traveling at 50MPH with 265/65/17 tires traveling at 'x' RPM's, that how it will calculate the f/a. When in actuality, you are traveling at let's say 60MPH at the same RPM's because of gearing and larger tires. You have already reached the 60MPH inertia point, less fuel needed. Etc...

 

Same here. mine sat in my garage collecting dust for almost a year before I installed it. Couldn't be happier with how it performs. I know this can be considered vanity, but after so many mods/$$$ spent it doesn't seem too bad.

 

I just tell everyone drive the speed limit and its fine. Or point out the ultragauge. But i also have to tell them to put it in 4 and not D.

Only a few people get to drive my truck so it hasnt been a concern. I have better things to spend money on