'98 Power Problem

Ill just put this here,

 

With a 3.4 and a 5 speed I still can't imagine its terrible on 33s with 3.91. I had a v6 auto Prerunner on 31s with 3.91 and it was fine. Not a race car but fine.

4.88 is way too high of a gear for a v6 with the 5 speed for 33s.

 

With a 3.91 gear ratio it's going to put your rpm at 70 at around 2300, which isn't bad. With 4.88, it'll be at almost 3000, which is pretty high. The engine is going to be working at highway speed to maintain that speed.

 

Hey can you use my data for that chart? 4.10gears 5speed V6. 265/70/17

 

http://www.grimmjeeper.com/gears.html

 

so feeling so close to a solution, and having something to search, "4.88 gears" I've spent most of the night realizing there is more opinions than gear ratios. I went to a few other forums "link chasing" and these guys were calling each other idiots, morons and liars. It's like arguing Ford or Chevy. I appreciate the more mature thoughtful TOYOTA minded atmosphere.

 

You had a Prerunner which did not have a transfer case to rob some of your output power like a 4x4 does.

3.4 motors love rpm.

A factory tire 225/70R15 with 4.10 gears and a 5 speed trans runs 2,337 rpm at 60 mph in 5th gear, and 2,726 rpm at 70 mph in 5th gear.

My 295/75R17 tires with 4.88 gears and a 5 speed trans runs 2,364 rpm at 60 mph in 5th gear, and runs 2,757 rpm at 70 mph in 5th gear. That is as close to stock gearing with 33" tires as you can get.

So, in essence 4.88 gears are not too low of a gear ratio to use with 33" tires.

A 265/70R17 is 31.6" tall. Running them with 4.10 gears and a 5 speed trans, will run 2,093 rpm at 60 mph in 5th gear, and 2,441 rpm at 70 mph in 5th gear.

 

4.10 gears stock.

 

I did have an auto trans though vs a 5 speed, which robs some power. The torque of the 3.4 was fine.

He'll be at almost 3000rpm at 70mph with 4.88 and a 5speed trans. That's a bit high, especially if he wants to go faster. The taller gear is also going to make the engine work more to maintain a higher speed than a lower gear ratio. His highway mpg will reduce.

I'm running 4.56 with 31s and it's a tad high. At 80 I'm at almost 3000rpm.

 

Did you not see my statement above about the stock rpm of a 3.4 & 5 speed with 4.10 gears and stock 225/70R15 tires running 2,726 rpm at 70 mph, and then with 4.88 gears and 33" tires running 2,757 rpm at 70 mph? How is the extra 31 rpm going to reduce his fuel mileage running 4.88 gears vs his fuel mileage on stock 4.10 gears and 28.3" tall tires?

I'm running brand new 4.88 gears with my 295/75R17 Toyo MT's which equals 33.3" tall. I have way better fuel mileage now with the 4.88 gears vs the 4.10 gears I just pulled out. Before I couldn't even get 200 miles on 3/4 of a tank, and now I have 200 miles on just a hair over a 1/2 tank used.

 

It's never too late for a thread to turn into a mileage or oil thread.

 

OP,
I have the 3RZ (2.7) motor, auto trans and gear driven transfer case. I run 285-75-16's and turn 2750 rpm @ 70mph running a 5.29 gear ratio. My truck weighs in @ 4300lbs. I do get around 16-17 mpg all day.
The higher the ratio number means lower gears, where the lower numbers are high, tall or steep gear ratios.

Good luck.

 

But he doesn't have 4.10s, he has 3.91s. And how do we know his truck came with 225s factory and not 31s?

My truck had 4.10 gears on 31s and when I put 4.56 in there, my highway mpg dropped. My rpm increased, and the engine has to work harder at higher speeds to maintain the speed.

It's like when you ride a 10 speed bicycle. In the lower gears and low speed, acceleration is great, but when start going faster, you have to work extremely hard in that low gear to maintain your speed. Or, you can shift up to a higher gear and it's much easier to maintain that speed.

A trucks rear gear works the same way. Lower gearing is better for acceleration, but not high speed highway driving.

 

In post #15 of this thread he posted the door sticker and his Tacoma came with 225/75R15 tires.

You can't maintain speed if the gearing is too tall (Numerically lower number) on the gear set, and you're running tires that are 2.5" or more taller than the stock tire size.

If he does any towing at all, he's going to want the 4.88 vs going to 4.56 gears. 3rd gen Toyota SR5 4x4 pickups that came with 31x10.50 tires stock had 4.56 gears on a normal basis. 3rd Gen pickups and 4Runners with Automatic trans that came with 31x1.50 tires had 4.88 gears in most instances.

 

Woah..so many numbers! I've got a Tacoma just like yours, except it's a 97. Do you have a lift on it? I have Bfgoodrich ko2 tires size 32x11.50xr15 and they slightly rub at full turn

I don't really have a power problem. Don't see why a size up would take such a huuuge toll but it could, I don't know.

Everyone is taking about regearing, why not start with the easiest and cheapest stuff

Change the spark plugs, change COILS and plugs change all fluids (engine, trans, diffs, transfer case), grease the drive shaft, clean throttle body, clean mass air flow sensor, clean iac, replace air filter, check your vacuum lines for cracks or kinks or vacuum leaks, replace fuel filter, USE FUEL SYSTEM CLEANER, (maybe do deck plate mod??!!)

Dude, try looking at your throttle cable. Maybe it could be tightened for better throttle response and the throttle plate isn't opening up fully when you floor the gas pedal.

Make sure your catalytic converter isn't clogged. There are many videos that show how to clean it with or without taking it off the truck. Check o2 sensors and if they are shot, replace them. Maybe get a nice exhaust to let the truck exhale easier


I'm being silly but why not check to make sure your parking brake cable isn't sticking causing the shoes to touch the drums.

Check the simple stuff first before you go blowing money. Autoxone let's you use their code scanner for free. Try it and see if your truck throws codes

If none of that works downsize to 32s or 31s.

 

I bought my truck new from the dealer. It has the an auto trans and was originally equipped with 4.30 gears and 267-70-16" BFG Rugged Trails. They gearing was awful, I never used OD.
The engine doesn't make enough power @ 2100 rpm and 70mph to get out of its own way. This issue and many others has been remedied.

 

Bringing the thread back. Didn’t want to start a new one. From what I’ve researched run 5.29s with 35s for an auto. It’s a weekend wheeler but does seem many road trips travelling at 75 mph for 4-6 hrs at a time. Will the 5.29s be to wound out for this highway travel?

 

What motor do you have?
I suggest 33's and 5.29's for the auto. I currently run that configuration. It's perfect for the area in which I daily commute.
Power... what's that? The auto trans kills anything power. Don't bring up 0 to 60 times as they do not exist.
Also, I have the 3RZ motor, can't say about one having the 5RZ.
Good luck.

 

I used to be a part of the Chevy crowd in the forums because of the car I owned (05 6.0 GTO) there were a lot of guys on that forum who were just legitimate assholes without a cause.

Don't get me wrong, this forum as well as any other one you go to will have that going on as well, but for the most part this crowd seems to be a bit more open minded and adult in their responses, and are less juvenile as a whole.

You would like the supercharger option. It is a great compromise between power and proper highway drivability. These trucks are not known for their high power making abilities, and in most cases you will be dogging it up the hill most of the time. Not with a supercharger!