2.7 upgrade to 3.4 is it worth it?????

[95tacoma4x4]

I have a 95 xcab with a2.7 180k+\- a few miles. Currently running 255 BFG mudders and the engine is really sluggish. Been thinking of upgrading the engine to a 3.4 for better power and performance. Found engine for a good price. Not sure if worth upgrading the engine or not? Also not sure what all the other parts I will have to replace??? I would imagine exhaust manifolds for sure what about the ac unit, also can I swap over current ac unit parts mount to 3.4. Torque convert also. Anyone every do this and is it worth me spending the $1700 on another engine plus extra parts if needed???
Any thoughts????

[Enola Gaia]

(1) Welcome to CT!

(2) Has the 3RZ been getting 'sluggish' for a long time, or did it suddenly seem challenged with the last tire / wheel modification (or any other mod)? I'm asking because something you've recently done may have challenged the stock setup and made it seem doomed when some sort of adaptation / adjustment may be all you need.

(3) There are multiple additional parts you'd need for a conversion - such as a 5VZ ECM, probably a whole new engine bay wiring harness, V6 motor mounts, etc.

(4) 4-cylinder and V6 Tacos used different transmissions and rear differentials (for both manuals and automatics). Even if you try to use your stock (4-cylinder) tranny, you'd probably be facing some tricky issues mating the 5VZ (bell housing, etc.)

(5) The 5VZ didn't change as much from 1995.5 through 2004 as the 3RZ and 2RZ did. However, there were some changes (mainly having to do with sensors and other auxiliary components). The farther away from 1995.5 the donor 5VZ is, the more such issues you'd have to deal with.

This might be one of those situations where you'd do as well to simply trade off for a V6 Taco. For a 18-year-old truck approaching 200K-miles, you might well be looking at total conversion costs on the order of what the truck is currently worth.

[thomas dominguez]

Dont forget about the ECM and all the wiring the front springs cuz the 3.4 is a lot heavier and the A/C pump is the same but all the brackets r different ..


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[95tacoma4x4]

The 2.7 only got sluggish when I put on bigger tires on. Sluggish might not be the wright words either. Have to down shift and keep the rpms high. I talked to a Toyota mechanic and he said with 2.7 when putting on a larger tire its know kinda issue power loss or issue turning toss tires.

Guess another option I could do is put gears to help keep the power there.

Or like you said trade up

[DanielTaco]

I would suggest trading. I used to have a 95 Extra Cab 2WD with the 3.4 and 32" tires. it never felt sluggish at all. I always had a good amount of power. I had the stock rear end gearing with a lock rite locker.

[Enola Gaia]

Originally Posted by 95tacoma4x4

The 2.7 only got sluggish when I put on bigger tires on. Sluggish might not be the wright words either. Have to down shift and keep the rpms high. I talked to a Toyota mechanic and he said with 2.7 when putting on a larger tire its know kinda issue power loss or issue turning toss tires.
...

It's certainly true that larger wheels / tires can add weight and make a 3RZ have to work harder.

However ... If you significantly increased the diameter of your tires, you've thrown off the ECM, and that by itself could cause 'sluggish' or odd engine behavior. The ECM uses the speed signal to determine how to control ignition and fuel. Bigger tires mean the speed signal is decreased (per unit distance traveled down the road), and the ECM 'thinks' the truck is moving slower than it actually is.

There are two typical remedies. One is to manipulate the speed signal to make the speedometer and the ECM accurate again. The other is to modify the final gear ratio so the speed signal is more or less accurate again.

What are the full spec's on your current wheel / tire setup? And what did you have on there before?

[95tacoma4x4]

I had been running stock tires BFG A/T. Recently jumped up to 255 and that's when noticed the sluggishness or lower power. Will have to look into the ECM sounds like that might be the fix that I need.

Truck needs some tlc I did put a new grip force clutch and it did help out a lil but will look into that.

[Enola Gaia]

The problem isn't the ECM. There's nothing you can do with or to the ECM itself to address this issue.

... And you still haven't posted the FULL spec's on your current tires. '255' is no more than one-third of a size specification (and, in most cases, the least relevant one). We need to know precisely what you've got mounted.

[S.Tacoma]

My truck has the 5VZ. Its pretty awesome. 171 000 miles on it, runs like a champ!

Yeah the springs for sure. A340F auto transmission. Be a good chance to beef up your frame in the front of the ladder right by the differential and in front of the cab where it gets a little thin. Bigger rad. If you're 2.7 has the same 4 piston calipers the 5VZ does, while you're there convert to Tundra calipers/discs.


Isn't there a mad assortment of aftermarket support for the 2RZ/3RZFE engines? 5VZ is gaining support but not as close as the others.

Funny enough I was thinking of going to a 3RZ from my 5VZ one year.

If you build a 5VZ the 3VZFE (not to be confused with the 3VZE) from the Camry has a forged crankshaft. LCE sells a forged crank for $800. Bet you its the same thing.

Good luck!

[Chris D.]

since you upped to those mudders, have you regeared the rear end?