Last post on Dec 14, 2011 at 12:46 PM
You are in the Mazda MPV
What is this discussion about?
Mazda MPV, Van
Oct 14, 2003 (8:20 am)
IIRC, Honda had VTEC (their first US-bound VVT system) in the 1993 Acura Integra.
Mazda has been using VVT engine technology in other markets than the US but hasn't imported the technology until now.
Really, when you look at the power to displacement ratios, Honda's 3.5L/240hp motor is not much better off w/VTEC than Mazda's 3.0L/200hp motor. The Honda makes 68.6hp/ltr and the Mazda's motor makes 66.7hp/ltr. This would indicate that a 3.0L VTEC motor in the Ody would generate 205hp, but the Mazda's makes 200hp, without VVT. Throw the Mazda6 motor in the mix and you get 218hp for 3.0L... even more efficient than Homda's motor. But really, the VVT in the Honda makes at best, 1-2hp/ltr of an improvement over a non-VVT motor such as the Duratec used in the MPV. So, as the old adage goes, 'there's no replacement for displacement.' Well, there's always forced-induction!
The way that I see it, VVT generally moves the powerband north where it's less useable in daily driving, while you gain better fuel economy down low on the revband.
Oct 14, 2003 (8:39 am)
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Oct 14, 2003 (9:44 am)
tom: So Honda and Toyota are "cheapskate companies" selling "crappy" engines ? I don't think so, and neither does the majority of the market. Both Honda and Toyota have demonstrated over many years that they can mass produce these engines, deliver superior performance/efficiency/emissions, and keep them together over the long haul. It's not like their engine reliability has plummeted over the last 5 years, isolated trouble-spots notwithstanding.
javadoc: Your stats only speak to peak power output on the high end. It's my understanding that VVT(-L) has been used to extend the torque curve downward where everyday drivers can really use it. Isn't that how Toyota gets 95% of peak torque at just 1800 rpm without sacrificing high end power ? Honda does the same. So yes, in terms of peak output the differences are small. But the overall performance difference over the entire power band is considerable.
They have up to 3 cam lobes per valve to account for low-, mid- and high-rpm settings. There is no way to get optimized engine output over such a large rpm range without varying both the cam timing and the lift (VVT-L, and similar). Or have I completely missed the boat here ?
#6666 of 8223 good discussion...
Oct 14, 2003 (11:19 am)
No, I was saying that the benefit of VVT is not earth-shaking, but it does make small improvements. It's kind of like when twin cams came out in the '80s in full force,in the US. You had all of these single cam, 8valve engines, and all of a sudden everyone had twin-cam, 16valve motors. The power difference wasn't incredible, and the power was all made up at the top of the rev band, while the 8v motors had great torque down low, but gave up a few ponies on the top. I guess I'm just saying that mechanical complexity isn't the cure-all, and that the Honda motor makes it's torque and power numbers more by displacement than by VTEC.
Good point on the torque however. I forgot to mention that. The latest versions of VVT technology are incorporating ways to bring the torque curve lower, into a more useable realm.
However, if you drive an Ody, you'll notice a large soggy section in the midrange, although off the line torque and high end hp is good. The Toyota version is better though. I don't know if Toyota is using VVTL-i in their Sienna (I've only heard them call it VVT-i), but I'll let you know how well the power is distributed, when mine arrives in a couple of months.
Oct 14, 2003 (12:04 pm)
Just finished a trip over the Columbus Day weekend.
We drove a little over 500 miles. Mostly 70 mph with the A/C on. Two adults, three children 8,10,13. Approximately 100 lbs of cargo.
26 mpg on Mobil 87 octane. I run Mobil 1 5w-30 in the Duratec. 19,000 miles on van. New OEM air filter at 15,000 miles.
The DW regularly gets around 21 mpg in her city commutes.
#6668 of 8223 Good-bye sulfur smell (I hope)
Oct 14, 2003 (4:42 pm)
A Mazda rep called to say that Mazda has come up with modified catalytic converters that they will install in smelly MPV's - free. Then my dealer called to say that they are waiting on the parts and they'll do the work. Yea! Good-bye smell!
#6669 of 8223 No change
Oct 14, 2003 (4:51 pm)
Nothing can replace Displacement....
Cheapskate companies with crappy engines use VVT.
Plus it is insane to use this nonsence for everyday cars... "Oh boy, I can get 2or3 hp after all that work and complicated flaky technology while driving 20-45 mph to work"...
Why not build a slightly bigger engine with a simple reliable timing system???? Which will get better milage.... If you were burning gas/kerosene/propane, ok VVT is necessary... Or trying to make different engines run with the same tranny(cheapskates)..
I don't like to use a beautiful highway engine like the MPV Duratec to do commuter work. We use the other car for town driving..
Honda and Toy are major cheapskates that is why I will never buy their products again after being burned....
"KISS" is the golden rule for engineers..
#6670 of 8223 re: help
Oct 14, 2003 (5:37 pm)
Try automotive "Goo Gone". It can be purchased at automotive stores and I think Wal Mart. It worked wonders on the massive road tar marks that I had on my vehicle and is very easy, safe, and inexpensive if it doesn't work.
Oct 14, 2003 (7:14 pm)
Honda and Toyota are major cheapskates? There might be a few million people who'd disagree with that statement.
Oct 14, 2003 (8:41 pm)
I would disagree as well. I think that Honda and Toyota have vast budgets for engine technology development, and they come up with some very good powerplants, with a few exceptions.
What does this have to do about MPVs? Hmmm... I'll scrounge for content. Not having this type of technology deployed in the MPV (as of yet) hasn't been a point which has cost the company much, if anything with the press, I think. Sure, the sheer hp figures are a tad lower than the big-two, but ah, what's a few ponies among friends?