nunsa

First off I got rid of my '89 w/ the 3.0, The rust and the nickle and diming was killing me! If I had to compare the both, let me think about it. Here we go, My modded 3.0 difinetly had more low end torque without a doubt, that was the thing I love about the 3.0, the low end torque, power was about the same, the 3.4 has a little more throttle response than the 3.0! The fuel mileage is better on the 3.4 > 23 - 24 mpg, my 3.0 was getting around 21 - 23 mpg, a little savings! The only thing I hate about this Taco is the seats, they absolutely suck! My old '89 had full power seats from a Chevy, Jimmy, they would go up down recline...! The stock 3.0 puts out about 150 HP I've yet to feel that or see that, whereas the stock 3.4 puts out 190 hp I felt it and seen it. There's a reason they call them the 3.slo, don't get me wrong, I love the 3.0, it's a workhorse and a half it just needs some more goodies to get her to run w/some power!
Take Care,
Harry

94x4

Thanks for the comparison info, "nunsa", although I'm working on something with the 3.0 that would flat out spank that 3.4! As I feel it should have been doing all along!, but that's for the future.

So how about your "expert" input on the crossover pipe/stock header conversion method that I mentioned above??

nunsa

Your post is interesting, have you evr seen the exh. manifold on a 3.0?
Kinda small, it's not taking enough air in or letting enough air in!
A lot of people don't belive me when I tell them that the biggest problem with the 3.0 is that it can't breathe, it's congested so to speak! Replace the x-over, get yourself some headers, 2 1/4" exh., freeflow cat, air intake mod., now the engine can start to breathe, ahhh! Whether you believe me or not, that x-over is a mis-engineered power robber, it causes the engine not breathe and burns up that #6 valve! True story! When I r & r'ed my 3.0 last year she screamed, no sh**! No one ever believed that you could get close to 190 hp out of the 3.0, I did! I also had the heads ported & polished, Supra AFM,oversize valves and injectors. That timing spec is wrong for the 3.0, as I mentioned in another post, My timing was retarded 5 Degrees! She screamed! You couldn't beat the Low end torque!
Good Luck!
I want to see your 3.0 put a 3.4 to shame!

CoedNaked

See it's interesting your thoughts NUNSA because I know a master Toyota tech up here in Canada who is of the general opinion not to screw with the 3.0 and it'll go forever. And I get the impression from him that once you start modding it your durability goes for a crap. However my opinion after analyzing this as well as your thoughts is that if I did mod out my 3.0 a little bit - maybe even just headers and a good 2 1/4" exhaust as you recommended, I wouldn't have to push the engine so hard and thus durability/reliability would probably be about the same - yet I would have that extra kick for towing/hauling, etc. when needed which is what I want for later on down the road when I buy a boat. However I think there are little idyosycracies (sp?) about the 89-95 pickups that make me feel overall they are just a downright better truck than the 96-04 Tacoma's (at least in similar configuration). Except the engine. While I love the 3.0 - it has character, and like you said - she's a torquey mofo, the 3.4 is in some respects is everything the Toyota learned from the 3.0 expierience as much as the 2.7 is everything Toyota learned from the 22RE expierience. Thus the 3.4's and 2.7's have excellent reputations so far overall.

The only real problem I have with headers & exhaust is the sound - I personally prefer the stock exhaust system on the 3.0. It's quiet, and has a good sound to it. I don't want more noise - but I do want the performance.
I guess she's all about trade offs?

miket223

Whenever I perform a valve adjustment service on a 3VZ-E I set the #6 exhaust valve as loose as the clearance specification will allow. I have never seen one come back with a torched valve. I have gotten a few minor complaints from customers about a valve tick. But, we all know how easy it is to brush off that complaint with injectors, VSVs, and "that is how the valves are supposed to sound when adjusted properly" excuses. And then I check for the busted steering shaft seal and they are all busted pretty much and that shuts them up. I don't want customers thinking things are making weird noises because I'm compensating for an obvious fault in the 3VZ. That scares people and I want them to come back and buy more Toyotas. It's okay if it's on our own 3VZ-Es since we understand the issues.

94x4

Having a 3.0, I would have to say that, "yes", I have seen the exhaust manifold, "nunsa". It's their being "kinda small" in size that makes them ideal for this mod, afterall, imagine just how much flow you would achieve porting them; the exhaust would dump straight from the the engine, to the almost nonexistent headers (particularly after porting!), to the exhaust & out with there being no restrictions on flow but the cat(s) and muffler(s).

So what's wrong with, say, removing the crossover all together;
Losing the driver's side exhaust manifold & replacing it with one from the passenger side that's been turned upside down;
Porting both stock manifolds (just how easy would that be, what with their short runners & all, you could open them up easily!!);
And then running the 2.25" exhaust out from there through one (with a "Y" or "X" pipe to join the two together), or two (if you stick with duals all the way out), high flow cats, humh ?!?

Would that not allow the engine to "breathe" & at alot less expense by eliminating the need for aftermarket exhaust manifolds ? Remember, the goal here is to remedy the problem without creating another problem...expense.

Still looking for input on "this" mod.

And you WILL "...see..." it (nunsa) after I drop a T3-T4 hybrid in there !

The 3.0 being such a "...torqey mofo..." (CoedNaked) on it's low end is what is another indicator that points out to me that the motor is supposed to be turboed.

[p.s. Uh, excuse me, "Mods", but do you think that there is anyway that I can get this info about the crossover mod posted in a "post" of it's own, starting with the initial 2:52 am one from early this morning & pasteing together the other responses about this mod into one thread or something, so that it would recieve wider review by the site's members to gain more input ????
Would much appreciate it, as surely would all other members as this is going to save everyone alot of money so they'll be able to better spend it on, say, "suspension mods"
Thanks in advance guys! ]

94x4

What happened, nunsa, did I scare you away or did you finally grasp the feasibility of turboing a 3.0 and that it would, indeed, spank the 3.4 !?!

phorensic

I've been wanting to turbo my 3.0 for a long time. Here's my take on a possible exhaust plan for doing it. Use the path that the crossover used to cross the exhaust to the drivers side, but use custom manifolds and tubing to get it done. Why use that stock restrictive stuff? I'm sure there's enough room to fit at least a 2" pipe back there. You will get rid of that resonator/pre-cat thing that I'm sure doesn't help flow. It *does* look like the stock system is designed for a turbo, but custom work can polish the design. Oh yeah, and you wouldn't dump the passenger side backwards into the drivers side manifold, of course, they would both coverge at a turbo flange.

Now you just need the MAF conversion that they are working on in another thread on this board, the split second unit to tune, and a fuel system that can keep up (bigger injectors, bigger pump). Just wish I had the cash, because I know a fabricator who can make the custom manifolds. 250whp should be possible without blowing the bottom end to bits, and if you do there is always upgraded parts at http://toyotaperformance.com/3_0l.htm . I'm going to port my heads before delving into this turbo thing, should make making power easier.

94x4

Hey, phorensic, while you're having the heads ported, why not drop off the exhaust manifolds for porting as well ??

They'll be easy to do due to their size (shortness), you won't have to finance aftermarket headers and because they are sooo short, once ported, it will be like they're not even there and dump right into the exhaust pipe (if you intend to maintain the stock, single outlet exhaust), or pipes (if you intend to run dual exhaust, although I suggest [as I did in a previous post]obtaining another passenger side header, to put on the drivers' side, and porting that).

Why have'nt I suggested "...custom headers and tubing..." ? Because this has been about eliminating the crossover and associated issues as inexpensively as possible, foregoing the expense of aftermarket equipment when, by all appearances, everything that you need has already been provided for you by TOYOTA. It's merely a matter of sorting out the puzzle of convoluted intake tubing and oddly arranged exhaust configuration.

p.s. With the stock setup, there's actually enough room for a 3" pipe back there!

Bumpin' Yota

ok there are TWO trains of thoughts goign on here:

First is that we are modding a N/A 3vze for power using the inverted/flipped manifold making a poor man's headers.

Second is the turbo application and that's what I want to address. If you turbo, you will WANT the crossover to be smallish. Stock size only mandrel should be fine. Remember you want that exhuast gas HOT and moving FAST when it hits the turbine.

And ideally you'd build a set of turbo header from a ISHTLOAD of u pipe. *shudder* (I have experience doing this - its worse than fiberglassing custom boxes...weld grind weld grind weld grind jbweld grind jbweld sand jb weld sand....aaaaaaaahhhhh wheres my 45??) Anyhow that would give the best results as far as a hot side turbo application. Now if it's actually WORTH doing all that work for ~40hp....i dunno you tell me.

Bumpin' Yota

ps - check the #6 exhaust valve's valve lash every 80k! Its rediculously easy to pull that valve cover and shove a feeler gauge in!

You will want the lash to be at 0.013"!

The normal range specs are 0.009" to 0.013" for exhuast valves

94x4

Oh, and I'm looking at a bit more than a "~40hp" increase.

94x4

99_Runner

So 94x4, when are you actually going to do this mod? I'm just curious as to if you are really serious about this, or just making it sound believable. It sounds good to me, but I will believe it when I see it.

If you do pull this off, then my hats off to you for coming up with a great, and hopefully cheap, way to get some more power out of the 3.0.

94x4

As soon as my friend gets some free time at his shop, although things are pretty busy for him, what with summer here and all, there's alot more people on the roads and, apparently, not all of them know how to drive and/or about maintaining the maintenance on their rides, but what can you do ?

Another thing is that my 'Runner is my DD and it would be a serious hurt for me to be without it, which is why I need to wait for "free time" so that I can get in there and out all in the same day, but I'm not letting that stop me as I'm currently salvaging about for an exhaust system so that I won't have to incapacitate my 'Runner any longer than the time required to swap out exhaust systems.

phorensic

My thoughts exactly. That's why I quoted 2" pipe. I figure 2.5" would slow the velocity way too much. Of course, you would want 3" from the turbo to the muffler.

40hp gain is weak. I want 100 more HP. Hell, 250whp requires more than a 100hp gain (at the flywheel). Maybe we can show those 3sgte, 7mgte, 2jzgte, rb26dett, and 13b guys that they aren't the only ones doubling and trippling their horsepower easily.

94x4

That's why sticking with the "stock" setup has been encouraged...now you're catching on.

Bumpin' Yota

No, no no, wrong comparison....

In a turbo application, the differences in turbo manifolds...

A custom built from scratch turbo manifold should produce 40odd more hp than a OEM modified turbo manifold for the 3vze. And considering the work involved in building a set of custom manifolds, 40hp aint worth it unless you are pushing 300hp....

Of course a turbo application had BETTER increase hp output by 75% or something is wrong...

94x4

Does T3-T4 Hybrid mean anything to you ???

99_Runner

Yep, it means something. How much boost do you really think you are going to be able to pump into an engine that already has a problem blowing HG's? I just don't think that I would be ready do put a turbo on the 3.0 unless I rebuilt the whole thing with forged internals so that I knew it could handle the boost.

Again, if you can pull this off, and have it be reliable for several thousand miles maybe even a hunderd thousand miles, then I will be one of the first to say congrats.