Driving at 1000 RPM

I've thought about it, and there certainly is a good reason to vary your RPM to the higher range every now and again. You probably haven't noticed, but if you give it the berries above 3-4k, the valve timing changes and things get a lot more exciting. This is because of the dual nature of the 3.5; the lower RPM range uses an atkinson cycle whereas above a certain range more valves are used and power produced because the engine operates as a normally aspirated engine. I would want whatever machinery is involved in the changeover and each mode to get some work at least some of the time.

Compare and contrast with engines that disable cylinders for "eco" mode, and subsequent gummed cylinders and ring wear as the cylinders come back online.

 

It was said that most of the 3,500rpm surge is just the ACIS valve opening at a non-optimal RPM. OVT changed that and that surge is gone.

But like you said, the VVTi and other functions working in this motor produce some interesting side effects and should be exercised, or exorcised.

 

one of the nicest things about that tune, the power isn't just saved for high rpms, but fills out the low mid. makes the truck so so much nicer to drive.

 

That is the truth and would be the exorcism route!

 

Break in. That is a long debated subject. I can tell you from experience that after a rebuild ( diesel engine ) here at work the engine goes into the dyno room. It gets fired up and checked for leaks and obvious problems and if none show up, the throttle is pegged and left there for about 8 hours. These engines then go into equipment and get beat for 750,000 to 1,000,000 kms. I am not overly concerned about break in.

 

Ok, now that is the kind of explanation I can accept. I tried to inform myself about what the 'Atkinson' cycle is precisely but I am still rather vague about it. Maybe I lack background knowledge. Just to be on the safe side I'll go ahead and rev it up to 4500 once in a while.

Am I right in assuming that using OVT will void the warranty?

 

it cannot be detected by the dealer under normal circumstances.

 

Atkinson is simulated on this engine using the VVTi system. Just hangs the intake valve open a bit on the compression stroke.


Technically it voids the engine warranty, but it is not detectable, and given the characteristics of the stock tune, it is most likely better for longevity.

See the attachment for a good explanation of the engine.

 

I have an automatic, and just realized the other day, that I rarely go over 2k on my daily drive. Unless of course I have to pass some slow spaz.

 

Thanks.
So now I need to think about Overtune, removing accumulator, rust protection (meh, I am in Nevada), suspension upgrade, tires. Holy long-suffering wallet, Batman!

And what is 'normal circumstances'? Abnormal being that, if for some reason, they take a checksum of the code and compare it to what it should be? In case there is a Toyota mandated firmware upgrade?

 

I told you! Get out while you can!

If you still see gaggles of spotless 1st Gens running around, like we do here, you don't have to worry about rust. OVT will most likely pay for itself in about 5yrs of normal driving.

There is no checksum on this ECU. If the dealer plugs in, all they see is the code for the stock configuration, 04B90 in your case. The ECU does report time and mileage since the last DTC reset, but any common OBD tool can reset the DTCs (diag codes).

 

Yes, I think that has been explained by the need to tune the automatic towards high gas mileage. It is also the reason why I think driving low RPM won't hurt the engine - after all, there are about 20 times as many automatics out there as there are manuals and if this would be bad for the engine - oh boy.

 

Could be too late...

Yeah, I am not going to worry about it. Especially since I am garage-parked. (Barely, got about 5 inches to spare)

This is starting to sound sexy. Especially since I am a software guy. I gots to look into it.

 

This engine likes to rev. The tach goes up to 6200rpms. The older 4.0 only went up to 5600.

 

rust in Nevada can be attended with a steel brush and a little black spray paint when & where you need it.

not a quote but more or less understood from OV Tune's posts, is normal circumstances would be anything except a 1 in a million engine problem that got Toyota Corps attention to the point they literally go through the code line by line to see what's up. and that would likely never happen.

also want to chime in on what @tonered said. i strongly agree - and there are many of us here that do - that the OV tune offerings are a healthier choice for engine life not to mention performance, and you can hear it and feel it when you drive. there's more discussion on this around here.