4.0 vs. 4.3

legacy2 · Post by **legacy2** » Fri Jun 24, 2005 12:43 am

ok, easy question that i cant answer. a friend has a mazda truck with a 4.0 V-6 in it and it has 210 horsepower and my mom has a 4.3 V-6 Vortec and it has 190 horsepower. with experience i find out that its easier to burn out with the 4.3

so does that mean that the 4.3 has more torque becasue its bigger? dumb question but im curious

dzx · Post by **dzx** » Fri Jun 24, 2005 2:11 am

It might depend on the bore and stroke. Most of its power may be geared down low and has a low hp rating because of it. Dunno tho.

corsair · Post by **corsair** » Fri Jun 24, 2005 3:44 am

Mazda max torque is 238 ft-lbs.
Chevy max torque is 250 ft-lbs.

Displacement? Mebbe.

BAC5.2 · Post by **BAC5.2** » Fri Jun 24, 2005 6:10 am

Gearing, cam grind, intake setup, exhaust setup, bore, stroke, brake weakness or strength.

There's about a dozen variables that can dictate what can burn out better.

Easiest solution: Research. Find out which truck makes more torque, and find out where they make the torque. Easy.

legacy2 · Post by **legacy2** » Fri Jun 24, 2005 12:49 pm

corsair has it right, chevy has 250 at 2800 rpm and the mazda has 238 at 3000 rpm. not that it really matters anymore but im not talking about powerbraking, im talking about flooring it from a stand still.

BAC5.2 · Post by **BAC5.2** » Fri Jun 24, 2005 2:18 pm

Yes, but that doesn't mean the extra power comes from the extra .3L, or that the chevy does better burnouts from a standstill because of the extra power. There's a ton of differences. The 4.3 is a pushrod motor, the Ford 4.0 is an SOHC motor. The gearing is different, and that's just a few things.

The added torque could be one reason, but other factors can effect things more than power. A friend of mine built a 1.8T Impreza with an RS tranny and could spin all 4 205/50/16's slightly more than my SS can spin 225/45/17's. I make a lot more power. It's all about setup, not just about power.

legacy2 · Post by **legacy2** » Sat Jun 25, 2005 12:31 am

ok, this has nothing to do with the topic, but what would you rather have or which is better, OHC or pushrod?

scottzg · Post by **scottzg** » Sat Jun 25, 2005 12:49 am

depends on the application.

OHC tends to rev higher, is more mechanically simple and tends to return better mpg, pushrod has a lower CG.

BAC5.2 · Post by **BAC5.2** » Sat Jun 25, 2005 7:03 am

Pushrods tend to be louder, which is cool, and they clack a LOT with a hot cam, which is also cool. They can make a ton of low-down torque.

I wouldn't want any of the OHC Fords until they FIXED the problems they had in 1997 when they went with the new SOHC 4.0. Pre 97, they used a pushrod setup, and it licked the balls unless it was the 4.0, and the new 3.0's outperform the old pushrod 4.0's.

scottzg · Post by **scottzg** » Sat Jun 25, 2005 9:41 am

BAC5.2 wrote:Pushrods ... can make a ton of low-down torque.

Torque is determined by displacement and flow (ignoring forced induction) Cam position, cyl configuration, etc have nothing to do with it.

Pushrods tend to make a lot of low end tq because we dont have too many small displacement pushrod engines running around anymore.

evolutionmovement · Post by **evolutionmovement** » Sat Jun 25, 2005 11:46 am

They make low end torque because they are two valve engines with breathing characteristics that suit low rpm as well as being large, of course. Comparing them to older relatively large displacement OHC engines (mainly European engines from pre variable valve timing days as that screws everything up) would make it appear that the pushrods had something to do with the torque characteristics, but it is really down to tuning for a specified range. Euros went for HP and top end while the Americans went for low end as preferred by their particular clientele.

Steve

legacy2 · Post by **legacy2** » Sat Jun 25, 2005 6:07 pm

well, they must have fixed the problem with the Ford engine, becasue that little 4.0 can go, and has never had a problem with the engine, im saying this even though im not really into Ford

legacy2 · Post by **legacy2** » Sat Jun 25, 2005 6:10 pm

also, does anyone know what good the "posi" rear end does, the mazda truck has it and you can always get a squeel out of a tire when you are turning sharp, and its always one of the back ones. anyone know what the "posi" rear end is good for???

scottzg · Post by **scottzg** » Sat Jun 25, 2005 6:37 pm

posi is limited slip differential. it locks both rear wheels together to a point. When youre turning, the outside wheel goes faster than the inside, so the inside has to fight the posi differential.

legacy2 · Post by **legacy2** » Sat Jun 25, 2005 7:10 pm

but is there a positive to having posi?

corsair · Post by **corsair** » Sat Jun 25, 2005 7:16 pm

uh when you stomp on it both wheels grip?

it has all the same positive qualities as a LSD, increased traction, and uh increased traction?

scottzg · Post by **scottzg** » Sat Jun 25, 2005 7:24 pm

a posi delivers power to both wheels at the same time, better traction.

legacy2 · Post by **legacy2** » Sat Jun 25, 2005 7:47 pm

yea when i stomp on it both wheels squeel and leave nice long blackies, i was just wondering, i didnt know if it had anything else it did but better traction

entirelyturbo · Post by **entirelyturbo** » Sat Jun 25, 2005 7:57 pm

Plenty. Better traction both in turns and in a straight line.

Ever see these dumb-ass Honda guys do one-wheel burnouts?

That's because they have an open diff instead of an LSD. If they had an LSD, they'd burn out both wheels.... actually.... they probably don't have enough torque to burn out both wheels, so they'd just stall

legacy2 · Post by **legacy2** » Sun Jun 26, 2005 5:24 am

well, im just sayin, i love honda's as well as subaru's, my brother had a 1999 Civic Si, and currently has a 1999 Honda Civic hatchback, but yea, i agree the non-Si honda's have no power. another question, so like say a honda, if you burnout all of the torque goes to the wheel that will spin first right? without a lockup TC or LSD?

scottzg · Post by **scottzg** » Sun Jun 26, 2005 5:29 am

lockup tc is a different thing, but that's true of a lsd.

LaureltheQueen · Post by **LaureltheQueen** » Sun Jun 26, 2005 6:13 pm

I'm going to argue with you that "non-Si honda's have no power. That was a completely incorrect blanket statement to use. Not even "Si Honda's" have power most of the time. Guess how much power a stock 91 crx Si has? That's right 108 hp, and 105 ft lbs of torque. and you're right, that's a huge leap from the 96 that the dx has. :rolleyes: Hondas are nearly incapable of producing torque as well. It's the problem with their inline motor, inline 4 cylinder engines just have lots of trouble producing any kind of tq.
Another point is even if VTEC HONDAS (a huge difference from just Si Hondas) are capable of making any kind of power, how high up in the powerband is it? Usually just past redline.

The Si isn't even very much better than the non-Si Hondas anyway,and in some cases it's not even the top model. In civics, it's generally true that the Si is a quicker car, but not always. I bring up my crx example again. In the 4th gen prelude, the models went S w/ 135hp @5200 rpm and 142 ft lbs tq, Si w/ 160 hp @5800 rpm and 156 ft lbs tq and the VTEC w/ 190 hp @6800 rpm and 158 ft lbs tq. The horsepower increases, but the tq stays the same. You'll also notice that as the hp increases, so does the rpm that it's measured at. If you don't mind going up to your redline just to get power, then go for it, but I'd prefer a usable power curve to get going without sounding like a bumble bee.

I believe a more correct statement would be that Hondas equipped with VTEC have the possibility of being better performance wise, if all you compare is horsepower numbers.

Oh, and the apostrophe after the auto manufacturers seems to indicate a possessive, there's no need for it.

Sorry to be a bitch, I just woke up with a hangover, and this is the first thread that I clicked on.

BAC5.2 · Post by **BAC5.2** » Sun Jun 26, 2005 6:23 pm

My Honda only makes like 68lb-ft or so.... at 10,000 RPM...

entirelyturbo · Post by **entirelyturbo** » Sun Jun 26, 2005 6:28 pm

BAC5.2 wrote:My Honda only makes like 68lb-ft or so.... at 10,000 RPM...

But it's only moving a total of... what? 500 lbs?

I wouldn't mind having a screamer car like an S2000 that needs you to get it up to 6k for it to even go anywhere, but I would only use that as a weekend car or something. I'd go nuts using it as a daily.

scottzg · Post by **scottzg** » Sun Jun 26, 2005 7:54 pm

Non si hondas do have power compared to non si's. Power = torque / time, which is exactly what that peaky dyno chart you posted is showing.

LaureltheQueen wrote: It's the problem with their inline motor, inline 4 cylinder engines just have lots of trouble producing any kind of tq.

They have just as much trouble making torque as any other cyl configuration. Configuration DOES NOT MATTER... except for concerning harmonics.

And torque doesn't matter all that much either since with those hondas you get to stay in the lower gear longer, the lower gear is a better torque multiplier. With torque tapering off, it makes no difference if you short shift since it can't produce the power to take advantage of the top of the gear.

And describing where peak torque is doesn't tell much about the area under the curve. A good torque band is pretty flattish, and the way to make power is to keep torque at a high rpm.

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4.0 vs. 4.3

4.0 vs. 4.3