20 replies to this topic

[Frstnflt]

I have a 3rd gen Tacoma with a Swift full camper. Stock tires but would like to step up slightly in size. The power is inadequate both from a dead stop and highway. Downshifting to 4th and even 3rd on the interstate is often necessary. The orange virus tune helped a tad but not IMO as much as the forums raged about. My main question is how much would a regear help? I can see some value with dropping first gear lower but above that can it do anything that shifting behavior would not do(manual trans)? Would $2,200 (local quote for g2) be spent better elsewhere? Should I just rev the hell out of it and get over it? Assuming a catback exhaust and intake would improve it nominally.

[rubberlegs]

Have you weighed your truck/camper? This would not affect highway power much, but would affect from a dead stop.

[Ace!]

Re-gearing provides more torque, so it can be of great benefit, possibly at all speeds (your RPM will be higher at any given speed).  I've regeared one or two vehicles and it was money well spent.  I'm considering it for my full-size that has 4.30 gears.  If you do go off road it is also a great time to add a limited slip or locker since the differential is already open.  You can add a limited slip to the front differential, a TrueTrac.  It is gear based and does not give the feedback that clutch-based limited slips do in the front.  They are very driver friendly and provide a great deal of traction over the open differential.

Edited by Ace!, 11 December 2018 - 03:12 PM.

[rando]

I am surprised that you think it is inadequate.    I have a 2016 Tacoma (v6) with a Fleet Flatbed (heavier than your Swift) and have no issue with power.   It is no sports car, but can keep up with traffic with no issues.   I can cruise at 80 on the flat interstate (although I don't), maintain at least 60 up the steeps grades to the Eisenhower tunnel on I-70. 

 

One thing to realize is that the 2GR-FKS is a modern high revving engine, peak power (278hp) is near 6000rpm and peak torque is near 4500 rpm, so expect to be revving high when you are pushing it.    It takes some getting used to.

[Vic Harder]

One thing to realize is that the 2GR-FKS is a modern high revving engine, peak power (278hp) is near 6000rpm and peak torque is near 4500 rpm, so expect to be revving high when you are pushing it.    It takes some getting used to.

If peak torque is at 4500, then that is where you want to be when climbing up hills.  It might not be right at the max efficiency for that engine, but it might close!  If a regear helps you you be at around that RPM more often, then that's a good idea.

 

FYI, many a Honda S2000 and Miata spend most of their time well above 4000 RPM, and run many hundreds of KM/miles that way.  High revving engines really don't mind it.

[ntsqd]

If you do go off pavement I would caution against anything like a K&N air filter, in any form. Contrary to what their marketing might imply those are not used in desert racing except by those who are sponsored by them. And for good reason. They allow grit past them. I've experienced this first hand, it is not some internet legend. Nothing that I tried, the usual tricks for sealing an air filter like greasing the rubber seals etc., would stop it. Moved to a paper element and the grit stopped.

 

It does take some getting used to sustained reving of an engine to what for an older V8 would be near redline.

 

I've re-geared two trucks and drove one that had been re-geared prior to my buying for 125k miles. I consider the proper axle gearing for the use and tire size to be one of the most important mods that can be made. Some sort of rear Traction Adding Differential should be considered while the axle is opened up. This is probably the second most important mod for off pavement travel. A TAD in the front comes with some undesirable complications, I wouldn't do it under a truck intended to carry a camper unless you plan to go rock-crawling with the camper.

[cwdtmmrs]

I am surprised that you think it is inadequate.    I have a 2016 Tacoma (v6) with a Fleet Flatbed (heavier than your Swift) and have no issue with power.   It is no sports car, but can keep up with traffic with no issues.   I can cruise at 80 on the flat interstate (although I don't), maintain at least 60 up the steeps grades to the Eisenhower tunnel on I-70. 

 

One thing to realize is that the 2GR-FKS is a modern high revving engine, peak power (278hp) is near 6000rpm and peak torque is near 4500 rpm, so expect to be revving high when you are pushing it.    It takes some getting used to.

 

Interesting. What RPM's do you like at level freeway cruising speeds? Must be over 3200ish.

[Vic Harder]

Having driven a few vehicles that love to rev, I like this topic!  Granted my current 8.1L does not like nor need to rev much, however here is what I dug up on this engine:

http://www.exploring...omas-new-engine

https://en.wikipedia...oyota_GR_engine

http://www.toyotaref...ma16_engine.pdf

 

This post is informative as it points out that from 2300 RPM up the engine has good torque with about a 10% bump up centered around 4800. The BSFC Map appears to show max efficiency around 2000 RPM when under load, and a huge high efficiency range from 1200 to 3600 RPM when not (I think that is what it is showing).

https://www.tacomawo...6#post-11154522

 

FYI, stock Miata's are quiet happy at 4000 RPM at highway cruise getting 35 mpg doing so.  The flat roller 347 stroker I stuffed into my Miata was cammed to come alive over 2600RPM and redlined at 8200, and cruised at 3K at 75mph.  It got 30 mpg while doing that.

[craig333]

That'd be hard to get used since my Jeep redlines at 3000 and the diesel even less

[JHanson]

Frstnflt,

 

You actually answered your own question.

 

As you surmised, installing higher numerical diff gears would give you some extra pull in first gear with your manual transmission. Beyond that, all it's going to mean practically is that in each gear the engine will be turning slightly (depending on how drastic you go) higher rpm. So you might wind up in a situation where you might be doing, say, 70mph in 6th gear at 3,000 rpm, where with your stock gearing you'd be doing the same speed at the same rpm in 5th gear. But so what? The engine doesn't care what gear you're in. 

 

Furthermore, both your fifth and sixth gears, IIRC, are overdrive gears, and thus slightly weaker than the 1:1 or "underdrive" gears. Pulling a load up a hill the transmission is better off in the lower gear. The simple fact is, as was mentioned, these engines produce their highest torque (not to mention horsepower) at absurdly high rpm, and you need to keep the engine up in that region to get the best power.

 

Also, remember that a higher numerical ring and pinion is weaker than a lower one. It's been argued ad nauseam how much this affects durability and reliability, but the indisputable fact is that a 4.56 r&p is weaker than a 4.11 r&p, and a 4.88 or 5.29 are weaker yet.

 

If you plan to install taller tires the equation shifts a bit, and re-gearing will compensate somewhat for the added diameter. But you'll still be weakening your diff, and compounding that stress with the added rotational inertia and mass of the larger tires.