Why such little power for the 3.4L V6?

I think when you compare the 3.0 to the 3.4 there is a large difference. however Toyota tuned the cams for lower end as usual for the American market. My experience with flow benching the Toyota heads (4 valve) is that Toyota detuned the intake came to match the 52% average Volumetric efficiency to maximize the 0-40 times.

All the 4 valve double over heads cam heads did this. If the engine had the cam timing position sensor or the distributor on the exhaust cam you can retard the intake cam and improve you hp by about 20%. Toyota smallest head with 1.1" valve bench tested at 188 CFM (With he first generation 1.25" intake runner). In the next generation the cut 1/4" out of the runners and added significantly longer intake manifold runners to decrease the 0-40 times.

If you do a .050" base circle reduction on the cams, move the valve seats up and port the exhaust runners to 75% EV you will not only gain Hp you will also gain fuel economy. It has to have the 1st generation heads or J spec heads. I have found this to be true for all the 4 cylinders, this engine, and also the 4.0 v8. This is a direct result of the "V" block Hemi developed in direct partnership with Yamaha in 1960. It was only do to the American Market that they reduced the intake runners on the second generation DOHC 4 valve heads.

Moreover, you can see this in how they developed the VVTI's. They started with only changing the intake cam timing. Toyota has been detuning the intake timing for years. America was not read for for 90 to 105% VE engines.

I think I'm going to need to come back and re-read this again when I'm not stoned
 
Not to be a hater but that's BS.

The QX4 has tons of problems, and you see almost none of them wheeling anymore.

And every G35 or G37 I've ever seen is worn out as hell by 100k miles and burns oil.

https://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2679069

The 3.5 Pathys and QX4s are great fun, but I honestly think the 3.3 is more reliable. Engine issues in the G35 and G37 usually stem from the issue that they most often end up getting purchased second hand by some college aged dumbass that loves to bounce of the rev limiter in parking lots.

The problem with this thread is that nobody knows what they are talking about. Obviously, if you compare a 5VZ to a larger or newer engine it was come out as unimpressive. If you actually look at it from a comparison that makes sense, like same year and displacement, then this is an impressive engine. Main competition for this engine included Nissan VG33E, Mitsubishi 6G74, Isuzu 6VD1, Chevy 4.3, and Ford 4.0 Cologne. Compared with these, the 5VZ managed to be quite advanced without sacrificing reliability. There are competitors with high power figures, but they also had higher displacement. In terms of power related to displacement it is again quite good.

I guess the VQ35DE in Pathfinder tuning was a competitor, but it came five years after. Frankly that engine was a HUGE achievement when it came out. I'd put it somewhere up there with the direct injection 6VD1 in the 2004 Isuzu Rodeo as those late to the game V6's that had some seriously impressive advancements for the time, but didn't have the displacement size to keep up with the advertisements.
 
The 3.5 Pathys and QX4s are great fun, but I honestly think the 3.3 is more reliable. Engine issues in the G35 and G37 usually stem from the issue that they most often end up getting purchased second hand by some college aged dumbass that loves to bounce of the rev limiter in parking lots.

The problem with this thread is that nobody knows what they are talking about. Obviously, if you compare a 5VZ to a larger or newer engine it was come out as unimpressive. If you actually look at it from a comparison that makes sense, like same year and displacement, then this is an impressive engine. Main competition for this engine included Nissan VG33E, Mitsubishi 6G74, Isuzu 6VD1, Chevy 4.3, and Ford 4.0 Cologne. Compared with these, the 5VZ managed to be quite advanced without sacrificing reliability. There are competitors with high power figures, but they also had higher displacement. In terms of power related to displacement it is again quite good.

I guess the VQ35DE in Pathfinder tuning was a competitor, but it came five years after. Frankly that engine was a HUGE achievement when it came out. I'd put it somewhere up there with the direct injection 6VD1 in the 2004 Isuzu Rodeo as those late to the game V6's that had some seriously impressive advancements for the time, but didn't have the displacement size to keep up with the advertisements.

Except some do know what they're talking about.

The Vqs are nothing special. They have the oil issues I linked about. There's a saying, "the candle that burns twice as hot burns half as long."

That pretty much explains what's going on.

Toyota detunes their engines so they're never pushed anywhere near their max abilities. This helps them go ungodly far without rebuilds, but it costs a little hp and torque.

Nissan went the other way. They tuned their 3.5L way up, and that's basically why they all start running poorly just as Toyotas are getting their second wind.

As for tq/weight...

The 3rd gen has 3950lbs/220tq.

The 5th gen has 4600lbs/265tq. Barely a change of a few % between the two, so if you don't feel the 5th gen is particularly weak, I doubt you'd complain about the 3rd gen.

Anyways, pretty much any modern engine will get the job done if it works hard enough. You could put a 2.0L 4-cylinder in a 5th gen and fill it with people and luggage and it'd still be able to top 80mph lol. It just wouldn't be able to tow much.

I'm always surprised how puny the engines in 1930s work trucks and big cars were by modern standards of power... yet they got the job done fine.
 
lol

Well, I'm not stoned, and I still don't really understand WTF he just said.

But I think i'm starting here

https://www.youtube.com/watch?v=FeO-oZVILRk

This video explains VE of the cylinder. When I studied the VE of a cylinder head we are comparing the amount of air that can be pull into a specific sized piston through differing valve setups. The VE of an engine is more a ratio of HP to CC's or liters. Thus a 90% VE engine of 1500cc would be 135HP. Most engine berfore 2010 averaged 65 to 75% VE or about 75 to 86hp.

Developing HP is really about the math of the cylinder head more than anything because it determines you VE of the cylinder. This VE video does not take into account RPM. This is where Yamaha really opened thing up. Two 1.1" valves with .325" of lift with a 1" x 1.25" oval runner can flow 188 CFM Naturally aspirated. where a canted over with a single 3" valve and .650" lift flows 164 cfm. Moreover the torque loss variable between different valve trains has to be taken into account. I do not know the numbers but the shim over bucket DOHC has a significantly lower internal torque loss. The spring rates and seat pressures are much higher on .650" of lift.

Next there are two factor at that point that will determine power development. When the intake valve closes, arguably the single most important event in developing Horse Power, and the % of that volume of exhaust the cylinder can expel. Now there are several opinions about which % is best. For racing 85% plus is good but leaves little street-ability. 75% is a good number and seems to work well with the Toyota cams for the pent roof 4 valve DOH cam engines.

So far what I have found about these cams is that the profiles is well suited for 8300 to 8500 rpm before the power band runs out. while there are certain exceptions most will turn 7200 rpm. I have found that this is determined by the type of rod Toyota choose to use and the piston metallurgy.

The shim over bucket dohc design will easily turn 9k to 11k rpm, what hold this up is the crankshaft, rod length and composition, as well as the piston. Bottom line when piston speeds get up over 4300 the piston and con rod construction requirements become expensive, moreover the rod angle a bit touchy. How much the Rod length grows and the piston expand become very important.
 
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Fast enough for me!

Our belolved 3rd gems maybe numerically underpowered but those, I dare say, are just Specs.

Specs to me mostly are just that, data. Just like stereo specs - gobs of watts, they don't really mean much, what it sounds like does.

To me what really matters in this threads case is how you feel about the acceleration, again don't go to the specs 1/4 mile time or 0-60 times, go to how You feel about it.

I feel mine keeps up with anything on the road acceleration wise Except of course V8s or larger. I often find myself letting off the throttle cuz I'm way ahead of all those who just took off from the same red light. Would I like a bit more power for hills or towing, maybe but I'd rather have the longevity and ease of maintenance instead.

Enough said, now go drive! :cowboy:
 
Can we throw this thread in the bucket with the "Why Does Toyota Say to NOT Use The Frame For Safety Stands" thread?
Great info by a few here, but- judging by his responses so far- it will do the OP no good.
 
Can we throw this thread in the bucket with the "Why Does Toyota Say to NOT Use The Frame For Safety Stands" thread?
Great info by a few here, but- judging by his responses so far- it will do the OP no good.

OP is long gone anyways. For the life of me I don't understand why people consistently revive 2-3-5-7 year old threads unless they are seeking info, which is OK and the purpose of these forums anyway.
 
I think when you compare the 3.0 to the 3.4 there is a large difference. however Toyota tuned the cams for lower end as usual for the American market. My experience with flow benching the Toyota heads (4 valve) is that Toyota detuned the intake came to match the 52% average Volumetric efficiency to maximize the 0-40 times.

All the 4 valve double over heads cam heads did this. If the engine had the cam timing position sensor or the distributor on the exhaust cam you can retard the intake cam and improve you hp by about 20%. Toyota smallest head with 1.1" valve bench tested at 188 CFM (With he first generation 1.25" intake runner). In the next generation the cut 1/4" out of the runners and added significantly longer intake manifold runners to decrease the 0-40 times.

If you do a .050" base circle reduction on the cams, move the valve seats up and port the exhaust runners to 75% EV you will not only gain Hp you will also gain fuel economy. It has to have the 1st generation heads or J spec heads. I have found this to be true for all the 4 cylinders, this engine, and also the 4.0 v8. This is a direct result of the "V" block Hemi developed in direct partnership with Yamaha in 1960. It was only do to the American Market that they reduced the intake runners on the second generation DOHC 4 valve heads.

Moreover, you can see this in how they developed the VVTI's. They started with only changing the intake cam timing. Toyota has been detuning the intake timing for years. America was not read for for 90 to 105% VE engines.

I vaguely understand what this is about but have to agree the porting/valvetrain/tuning, and gearing, contribute to the '99 3.4's lack of power. My '03 Tundra base model 5-speed is like a whole different vehicle - peppy, quick and way more fun. It also gets about 4mpg better fuel mileage. Let's just hope gas prices stay down for a long time...
 
It's a shift in the standard of how much HP should be mad compared to the displacement.

3.4l is 207cinch which is 183/217 so about 195/207 and right about 94%
the new standars is 3.4l= 340 195/340 is 57%

57% is quite often the percent of exhaust CFM's divided by the Intake CFM's

if a 1.5l has 200 cfm going in one side of the head and 75% of that leaving the exhaust you get 150 Cfm and that is the target VE and HP for that engine. Now after all the pluses and minuses it's actually about 135 HP or 90%. When you compare that to the original 97 Hp of the 92Cin you can see why the rest of the world has made a shift in their colorations about observable power.

That's a 38 Hp improvement with a 5 mpg increase.

The only thing holding up our generation of engines is where Toyota place the cam position sensor.
 
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As above, its not really a comparison at all...

Different engines for different uses.

My old BMW was only a 3.2, but made 343BHP from an N/A straight 6.

That was in 2003 so hardly modern.

The engine in my truck is from a '99 and only makes 290 bhp from a 4.0.

Regarding quoted figures, most manufacturers will quote at the fly.. that's why they usually say "Engine output". It's a marketing thing.
 
Our belolved 3rd gems maybe numerically underpowered but those, I dare say, are just Specs.

Specs to me mostly are just that, data. Just like stereo specs - gobs of watts, they don't really mean much, what it sounds like does.

To me what really matters in this threads case is how you feel about the acceleration, again don't go to the specs 1/4 mile time or 0-60 times, go to how You feel about it.
Haha geez I literally made this same comparison talking to my wife last week. I have a 250 watt hand-me-down 5.1 stereo that I got for free, and a coworker just bought a 600 watt that he was bragging about.
I can barely turn mine up halfway without it literally hurting my ears. Why would I want more than twice as powerful? It's completely useless. Looks great on paper, but that's it.

I never understood the horsepower 'war'. Other than to make a better machine for the sole purpose of just because you can (totally fine; this is America), it's pretty pointless. Except for those rare places like the German Autobaun, unless you go to the track, you'll never be able to legally utilize the full HP of a vehicle, especially muscle/sports cars. It's all just for show. For bragging rights.



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Wasn't engineered to be super powerful. It's 9.6:1 compression, non interference. Supposed to be somewhat torquey and last a long time. Came out in the 96 runner? Was probably developed in 92 or something. It's way old at this point, especially compared to a VQ.

The 3.5 VQ is prob 11:1, variable cam timing, all sorts of engineering and tech advances.

You'd have to look at BMW's old M division inline 6's to find similar hp/liter back when toyota made this engine.
 
I know this has been brought up before and I'm sure beaten to death.

1UZ-FE . It was around during the same time and mated to the same transmission with a vehicle that weighs about the same 4,000lb curb weight.

I know torque of the devil did this swap already.

I have that engine in my 1999 LS400 and it is such a dream of an engine. Great power.

Anyway, this isn't about bragging rights at all. Horse power does mean you won't have to downshift on small hills. To me, it makes the whole driving experience more enjoyable.

I understand that horsepower alone is not the only factor that would help a vehicle hold gears better but it sure doesn't hurt


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