New GM LT1 engine

[Howard]

I just dyno'd my car, check out this power curve.

Your car has two horsepowers!?!?!? Oh shit NOS

 

[Throckmorton]

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

What I6 is that?

Edit: Oh must be the GM Atlas... Awesome engine. It would have been great in a sports car I think http://en.wikipedia.org/wiki/GM_Atlas_engine#LL8

 

[Throckmorton]

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?

It's from JP Magazine

 

[phucheneh]

It's from JP Magazine

I was still lost, then I looked at the image source and went to the home page...and I still don't know what JP means. Is it just their way of saying 'Jeep?' Or 'Jeep Power' or something?

Either way, I figured that it was a mag for Jeep guys. Which explains why it (the graph) sucks. A) They had to redraw it so it would fit in a little image box next to some text and still be readable and B) fanboys are silly. They really did try and make the pretty-tough-but-not-that-great-in-any-other-respect 4.0L look like the most beastly torque monster ever. For its power level, at least.

Also, to be fair, I6's in general, especially iron ones, are pretty tough. I drove a Ford 200ci small six like ten miles with the lower radiator hose blown off and it didn't even need a head gasket. :awe:

 

[SparkyJJO]

What I6 is that?

Edit: Oh must be the GM Atlas... Awesome engine. It would have been great in a sports car I think http://en.wikipedia.org/wiki/GM_Atlas_engine#LL8

Yep, the atlas. Aptly named. Very stout, I see a billion of them with 200k+ on them. I have 165k on mine. Providing the body doesn't rot too fast (went the wrong direction and bought it from north of here, and NY and Cleveland weren't too nice to it) I hope to get 250k+ out of the original engine/trans.

 

[Fritzo]

I just dyno'd my car, check out this power curve.

I dinoed my car. I don't think I did it right.

 

[LTC8K6]

http://www.wjjeeps.com/misc/curve_40.jpg

Why are we comparing a pushrod and a DOHC engine again?

 

[ND40oz]

http://www.wjjeeps.com/misc/curve_40.jpg

Why are we comparing a pushrod and a DOHC engine again?

I think they're trying to compare engines from the same era.

And wtf is up with that dyno? We'll use this scale for torque and this other one for hp, brilliant.

 

[LTC8K6]

I think they're trying to compare engines from the same era.

And wtf is up with that dyno? We'll use this scale for torque and this other one for hp, brilliant.

One is nearly flat, and one is a mountain.

 

[ND40oz]

One is nearly flat, and one is a mountain.

What does that have to do with the scales being different for torque and hp?

 

[LTC8K6]

What does that have to do with the scales being different for torque and hp?

It affects the way the graph looks, and, looking around, it's not unusual at all.

It gets both lines in the same area, and works well.

 

[ND40oz]

Eh, you glance at the graph and think it's making good power over 5250 rpm and it's torque curve is ridiculously long because of the point the two curves intersect. Then you realize that scales are all screwy and the curves should probably never intersect because it stops making power at 4600 rpm.

 

[Ferzerp]

HP to lbft ALWAYS intersects at 5250.... In fact, you don't even need to plot both lines since they are functions of one another. With one line you can always get the second. People just don't have a good understanding of it.

hp = (torque * RPM) / 5250

Always (in the proper torque units). There is nothing magic. That's why the guy who missed the units being N*M was confused when they didn't meet. The equation at 5250 reduces to hp=torque (in lb*ft)

 

[ND40oz]

Right, this graph is in HP and ft-lbs, the problem is they used different scales for HP and ft-lbs.

 

[LTC8K6]

Eh, you glance at the graph and think it's making good power over 5250 rpm and it's torque curve is ridiculously long because of the point the two curves intersect. Then you realize that scales are all screwy and the curves should probably never intersect because it stops making power at 4600 rpm.

The redline is only 5300...

It was designed for torque for rock crawling. People loved the engine for that. Hated the 3.8 V6 that replaced it.

Here's the Pentastar which they like again because of that torque.

http://www.wk2jeeps.com/engine/3.6_liter_pentastar_graph_01.jpg

Here's the 4.7HO V8 graph done the same way.

http://www.wjjeeps.com/misc/curve_47h.jpg

 

[Ferzerp]

I see that on a lot of charts. I don't prefer it, but it is common.

 

[ND40oz]

The redline is only 5300...

Right, Chrysler used different scales to try to make things look better, instead of just putting the numbers out there.

It was designed for torque for rock crawling. People loved the engine for that. Hated the 3.8 V6 that replaced it.

Here's the Pentastar which they like again because of that torque.

http://www.wk2jeeps.com/engine/3.6_liter_pentastar_graph_01.jpg

Here's the 4.7HO V8 graph done the same way.

http://www.wjjeeps.com/misc/curve_47h.jpg

Yeah, the 3.8 was a dog, the reason I didn't buy a JK, my 1GR-FE was a much better choice. The pentastar was the engine they should have had from the start when they ditched 4.0.

 

[Carfax83]

Since we're comparing European made engines to American, here's another comparison:

The updated W-12 engine that is now in the 2013 Bentley Continental GT is 12 cylinder, 6.0L, DOHC, twin turbo, 48 Valve that outputs 616hp and 590-lb-ft of torque.

For comparison, the new Viper SRT engine which is 10 cylinder, 20 valve OHV, 8.4L, naturally aspirated that outputs 640hp (est. likely higher) and 600-lb-ft of torque (est. likely higher)..

 

[Ferzerp]

Since we're comparing European made engines to American, here's another comparison:

The updated W-12 engine that is now in the 2013 Bentley Continental GT is 12 cylinder, 6.0L, DOHC, twin turbo, 48 Valve that outputs 616hp and 590-lb-ft of torque.

For comparison, the new Viper SRT engine which is 10 cylinder, 20 valve OHV, 8.4L, naturally aspirated that outputs 640hp (est. likely higher) and 600-lb-ft of torque (est. likely higher)..

If you're going to do that comparison, make it with the Trinity engine from Ford. 5.8L, supercharged, 662HP, 630 lbs ft.

 

[Howard]

Since we're comparing European made engines to American, here's another comparison:

The updated W-12 engine that is now in the 2013 Bentley Continental GT is 12 cylinder, 6.0L, DOHC, twin turbo, 48 Valve that outputs 616hp and 590-lb-ft of torque.

For comparison, the new Viper SRT engine which is 10 cylinder, 20 valve OHV, 8.4L, naturally aspirated that outputs 640hp (est. likely higher) and 600-lb-ft of torque (est. likely higher)..

Would be interesting to compare the BSFC of these two engines. I feel like the V10 is almost certainly going to be shorter than the V12, with a lower center of mass.

 

[Carfax83]

If you're going to do that comparison, make it with the Trinity engine from Ford. 5.8L, supercharged, 662HP, 630 lbs ft.

I wanted to use a naturally aspirated motor.

 

[Ferzerp]

Well, ok

 

[Throckmorton]

Would be interesting to compare the BSFC of these two engines. I feel like the V10 is almost certainly going to be shorter than the V12, with a lower center of mass.

The Bentley has a W12 not a V12... way too complex IMO

 

[Carfax83]

The Bentley has a W12 not a V12... way too complex IMO

You're right, I thought the W-12 name was just a codename or something, but apparently, it has 4 banks of 3 cylinders each, hence the "W."

Anyway, I was genuinely surprised at the relatively low power output of such an engine, despite it's size and performance enhancing features.

Does any American manufacturer make a V-12?

 

[phucheneh]

The W12 is just two VW VR6's stuck together. VR6 being a V6 with banks so close together that they share the same cylinder head. The W12 design is not too terribly different from a V12. The extra complexity is mainly in the heads.

There are still two rods per crank throw. Seven main bearings.