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New GM LT1 engine

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Ferzerp said:
The Dodge 6.4L is thirsty too. It's not thirsty compared to something like that from 10-20 years ago, but it is compared to cars now. Only car I've ever paid a gas guzzler tax on. The one I'm looking at now is almost 200hp more, and gets better mileage (and is DOHC).
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I think the perception of the efficient pushrod engines is solely due to the Corvette. Compare gas mileage between the old Ford 5.0L pushrod that made 215hp, and the new 3.7L DOHC V6 with 305hp.
 
I think it's going a bit far to say that an OHV engine is automatically more reliable than a OHC. Maybe that was true twenty years ago, yeah...

But how many people are worried about the reliability of their DOHC, typically VVT equipped Honda/Toyota/ect 4cyl engines? Especially when VVT literally just means variable timing- the variable lift and other more complex stuff is obviously a little less proven.

But so is VVT for both exhaust/intake on an OHV engine (relatively speaking).

And yeah, I know, apples/oranges and whatnot; I'm just saying that even on a V8, dual cams don't exactly make it less durable by default. The only real weak point is the timing (as in cam/crank) system, and those have gotten a lot better in recent years.
 
Fritzo said:
Why is it Germans and Italians can get 500HP out of a 5.0L engine and we get 450 out of a 6.2L?
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Chevy could do it as well, but they are smart enough to know, they don't have to. That's what the aftermarket is for. Compare the aftermarket for small block Chevy's vs any of the Europeans.

Chevy can play conservative with their engine numbers to increase reliability and simplify maintenance which keeps costs down for the masses. For those people that don't care about warranties and 100,000+ mile reliability, the huge aftermarket will let them push their engine as far as their wallet can handle.
 
Fritzo said:
Why is it Germans and Italians can get 500HP out of a 5.0L engine and we get 450 out of a 6.2L?
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I have seen 800 hp out of 1.3L motors... just a matter of time/$.

I agree that a big engine like a 6.2L putting out 450, is a bit lack luster, but down the road there is more to be made.
 
Pariah said:
Chevy could do it as well, but they are smart enough to know, they don't have to. That's what the aftermarket is for. Compare the aftermarket for small block Chevy's vs any of the Europeans.

Chevy can play conservative with their engine numbers to increase reliability and simplify maintenance which keeps costs down for the masses. For those people that don't care about warranties and 100,000+ mile reliability, the huge aftermarket will let them push their engine as far as their wallet can handle.
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"they don't have to"?????

they don't want to is probably more accurate IMHO. They want to keep costs down, especially warranty costs. Also, they want to keep the base model fairly low power to allow them to make small changes that cost very little, but develop significant bumps in power to higher cost models, so they have increasing margins.

there are many reasons, but they mostly revolve around $
 
phucheneh said:
I think it's going a bit far to say that an OHV engine is automatically more reliable than a OHC. Maybe that was true twenty years ago, yeah...
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OHC isn't unreliable by any means, but any system with less parts is going to be more reliable, all else equal.
 
Howard said:
OHC isn't unreliable by any means, but any system with less parts is going to be more reliable, all else equal.
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The assumption that OHC engines are superior is successful marketing at work 😉

They each have their strengths and weaknesses.
 
Sounds like an awful lot of on-paper peak HP number comparisons going on with out much attention being given to the torque and the power band of the engine.

Sure, engine X may get 280HP out of 2.8 liters while engine Y gets 250 out of 4.0, but if the torque is low on engine x and requires high revs to get that HP number and that additional 30 HP doesn't show up until right at at the end, while engine Y has more torque and a flatter power band, engine Y will still perform far better over all. Peak HP numbers mean very little without everything else taken into account. Except for marketing, I suppose.
 
SparkyJJO said:
Sounds like an awful lot of on-paper peak HP number comparisons going on with out much attention being given to the torque and the power band of the engine.

Sure, engine X may get 280HP out of 2.8 liters while engine Y gets 250 out of 4.0, but if the torque is low on engine x and requires high revs to get that HP number and that additional 30 HP doesn't show up until right at at the end, while engine Y has more torque and a flatter power band, engine Y will still perform far better over all. Peak HP numbers mean very little without everything else taken into account. Except for marketing, I suppose.
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Very true.

The BMW N55 and newer Nissan VQ are a good example- similar horspower, maybe 30ftlbs les torque on the Nissan.

The former smokes the latter. At least, it sure as hell feels like it does when you drive a 335 versus a G37- even if you took the extra peak torque away, the Bimmer just has a lot more grunt.
 
SparkyJJO said:
Sounds like an awful lot of on-paper peak HP number comparisons going on with out much attention being given to the torque and the power band of the engine.

Sure, engine X may get 280HP out of 2.8 liters while engine Y gets 250 out of 4.0, but if the torque is low on engine x and requires high revs to get that HP number and that additional 30 HP doesn't show up until right at at the end, while engine Y has more torque and a flatter power band, engine Y will still perform far better over all. Peak HP numbers mean very little without everything else taken into account. Except for marketing, I suppose.
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In 1996 Jeep had a 4.0L I6 putting out 190hp at 4600rpm, 225lbft at 3000rpm, 5300rpm redline

BMW had a 2.8L I6 putting out 190hp at 5300rpm, 210lbft at 3950rpm, 6500rpm redline
 
Throckmorton said:
In 1996 Jeep had a 4.0L I6 putting out 190hp at 4600rpm, 225lbft at 3000rpm, 5300rpm redline

BMW had a 2.8L I6 putting out 190hp at 5300rpm, 210lbft at 3950rpm, 6500rpm redline
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The 4.0L is known for it's resilience even now, you cannot say the same for the BMW M52.
 
Throckmorton said:
In 1996 Jeep had a 4.0L I6 putting out 190hp at 4600rpm, 225lbft at 3000rpm, 5300rpm redline

BMW had a 2.8L I6 putting out 190hp at 5300rpm, 210lbft at 3950rpm, 6500rpm redline
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So... BMW had a smaller motor putting out 15lbft less at 1000 higher rpm's? I'll bet that torque curve on the Jeep was dead flat. Are you making the argument for or against the OHV motor? And the GM 3800 series of motors through the 90's were also known for their flat torque curves.

OHV motors have their advantages. Which is why people get so defensive about them. HP/L is just one of many ways to judge a motor -- arguably the worst way.
 
KnightBreed said:
So... BMW had a smaller motor putting out 15lbft less at 1000 higher rpm's? I'll bet that torque curve on the Jeep was dead flat. Are you making the argument for or against the OHV motor? And the GM 3800 series of motors through the 90's were also known for their flat torque curves.

OHV motors have their advantages. Which is why people get so defensive about them. HP/L is just one of many ways to judge a motor -- arguably the worst way.
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motorcycle engines get 150-200 hp/L. jesus, why can't dumbass car manufacturers do the same? 😀😀😀

</troll>
 
KnightBreed said:
So... BMW had a smaller motor putting out 15lbft less at 1000 higher rpm's? I'll bet that torque curve on the Jeep was dead flat. Are you making the argument for or against the OHV motor? And the GM 3800 series of motors through the 90's were also known for their flat torque curves.

OHV motors have their advantages. Which is why people get so defensive about them. HP/L is just one of many ways to judge a motor -- arguably the worst way.
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My point is that the BMW is not that high strung, even though its almost 2/3 the displacement
 
My example wasn't arguing either way, just pointing out that different engines are...well, different. Not sure what the following post was about.

The N55 (3.0 DI turbo) is a fucking torque monster throughout the RPM range. The Nissan 3.7 isn't. At all.

If you're trying to argue that displacement = power/torque, the Jeep 4.0 is kind of a bad example. Really inefficient, underpowered engine. Its torque probably stems most from that fact that it's an I6, which has always seemed to produce more than V6 designs. Not sure what the science on that is...or if there is any. But I gotta think so, what with the rather ubiquitous nature of I6's in big trucks (as in semis).
 
phucheneh said:
My example wasn't arguing either way, just pointing out that different engines are...well, different. Not sure what the following post was about.

The N55 (3.0 DI turbo) is a fucking torque monster throughout the RPM range. The Nissan 3.7 isn't. At all.

If you're trying to argue that displacement = power/torque, the Jeep 4.0 is kind of a bad example. Really inefficient, underpowered engine. Its torque probably stems most from that fact that it's an I6, which has always seemed to produce more than V6 designs. Not sure what the science on that is...or if there is any. But I gotta think so, what with the rather ubiquitous nature of I6's in big trucks (as in semis).
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I6s are probably cheaper than V6s as long as you don't have to do anything crazy to fit them in (e.g. Volvo transaxle)
 
Zivic said:
"they don't have to"?????

they don't want to is probably more accurate IMHO. They want to keep costs down, especially warranty costs.
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Which is what I said. You're arguing semantics. If the competition made it necessary to bump the engine output, GM would do it whether they wanted to or not, so it is more accurate to say they don't have to, so they aren't.


Also, they want to keep the base model fairly low power to allow them to make small changes that cost very little, but develop significant bumps in power to higher cost models, so they have increasing margins.
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In theory, but GM has not done this with recent models, if they ever have. Neither the LS2 or LS3 were tweaked for more power during their lifespans to created higher cost models. The LS7 in the Z06 has no relation to either the LS2 or LS3. Though the LS9 is basically an LS3 with a TVS2300, it takes more than a few small changes that cost very little to upgrade an LS3 to an LS9.

there are many reasons, but they mostly revolve around $
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Which is what I said, but for some reason you felt like disagreeing to agree.
 
ND40oz said:
Torque curve on the M52 is pretty good, BMW tuned it for torque while sacrificing topend power due to the intake manifold. Tons of dynos here: http://forums.bimmerforums.com/forum/showthread.php?t=478545
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And here is a dyno sheet for the Jeep 4.0L from the same era with 130k miles http://image.jpmagazine.com/f/9052717+w750+st0/154_0412_litr_10_z.jpg

Jeep
0jUaV.jpg


BMW from here http://www.bmwfanatics.co.za/showthread.php?tid=20349 (stock but at high altitude apparently)
Edit: Forget this one, something is wrong with the graph because HP and torque never meet numerically


BMW 2.8 from here http://forums.bimmerforums.com/forum/showthread.php?t=478545&page=2
OQygH.gif
 
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Throckmorton said:
Wait, why don't HP and FTLB meet at 5250 on the BMW dyno?
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It's not hp on the left and ft lbs on the right like on most dyno graphs...does that say 'ambient power consumed'? 😕

edit: Ah fuck, ninja picture change. Seriously, what the hell was that other one?

Also, LOL@ Jeep 'dyno.' Sorry, man, someone just drew that. I mean, it could be a translation of a real dyno graph, but still...that kind of seems like something someone on a ricer forum would post.

edit2! : I have to look at stuff longer before I comment, shit. 3300-5300rpm 'dyno'? Really? I was wondering how torque could continuously fall off from idle...how about we see the uphill part of that rollercoaster graph?
 
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crappy graph is crappy.

I'm not saying one engine was better than the other because I don't know much about either one. My only point is you can't use peak numbers on paper to determine which engine is truly superior as there is a lot more to it.

That said, I'm happy with my 4.2L I6 pumping 275-ish HP/TQ peak numbers, and my 3.8L V6 pushing... well, no idea. It isn't stock so the only way to find out would be to dyno it 😀 When the 3.8L dies I'd like to swap in a 6.2L LS3 😀
 
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