IS GM capable of making a small block DOHC

[GretchenGotGrowl]

Originally Posted by demonspeed

Do you have a link to a LFX curve? I tried searching but can't find one.

Here's a LS1 curve: http://www.geareddrives.com/LS-1%20HP%20vs%20Torque.jpg

That's great that the LFX makes 250tq at lower rpm, but the LS1 belts out 325tq at 1800.

Now, when we introduce E/T's, do we also want to consider trap speed? If so, you're going to see several mph lower with the LFX simply due to the lower power.

As an FYI, I'm not trying to infer the LFX is an inferior engine. I'm only speaking in the context of racing against a LS1 in equally-bodied vehicles.

Yeah, DGThe3 posted it earlier.
http://www.camaro5.com/forums/showpost.php?p=6811088&postcount=32

The LS1 will kill it off the line. If I remember right it was stalled right around 1800 on the autos, so it was making about 110 HP when it launched. The LFXs are stalled to about 1700 and only make 80 HP off the line. But they are redlined at 7000 RPM and the torque drops off a lot on the LS1 after about 5500 RPM. They have to shift more to keep it in the power band. With 3.55 gears the LFX will stay between 5000 and 7000 the rest of the way down the track. That's pretty close to peak power. Still less power than the LS1, which is why it will be slower, but the difference is a lot less than just looking at peak numbers.

Not knocking the LS1, they are amazing engines and knocked Ford back on its heels. Mostly I got to thinking about all of this because the new LT-1 engine has a torque curve that is very similar to the LFX, just higher numbers. That thing will be a beast at the track with the right gearing and stall.

[Stew]

Originally Posted by SEVEN-OH JOE

Wow! You're right, of course, as the Town Car was certainly a beacon of performance for Ford in '92, Stew.

Now it was for the 55 plus club.

[demonspeed]

Originally Posted by GretchenGotGrowl

Yeah, DGThe3 posted it earlier.
http://www.camaro5.com/forums/showpost.php?p=6811088&postcount=32

my bad.


So, are we all in agreement that there is nothing left for GM to prove in the context of this thread? They've been there, done that, chosen to go a different route.

[GretchenGotGrowl]

Originally Posted by demonspeed

my bad.


So, are we all in agreement that there is nothing left for GM to prove in the context of this thread? They've been there, done that, chosen to go a different route.

Yeah, I sorta figure the DOHC/OHV argument is moot. If you want a DOHC V8 in your performance car then face it, your aren't getting it from GM anytime soon. If that's a deal killer then I'm sorry, but you are sweating the small stuff here.

[fielderLS3]

Originally Posted by demonspeed

Another aspect that gets overlooked is gearing. One could build a weak engine but put it in front of an optimally built (ratio-wise) transmission/axle.

Originally Posted by DGthe3

You own an Alero, which makes up to about 200 ft-lbs of torque (unless you've got a 4 cylinder) from a 3.4L engine -same as my Grand Am, and we can now get V6s slightly larger with 1/3 more torque. How is that not a big improvement in a decade? The V6 in the Camaro makes almost twice as much torque as its counterpart from 30 years ago.

The 1/3 increase from the Alero/Grand Am 3.4 in 10 years is a bit misleading, because even when these cars were new, the 3.4L wasn't exactly cutting edge (it was arguably about 15 years or more old then already). And the 2.8 fuel injected Camaro had about 165 ft-lbs. Per displacement, that is only about a 30% increase in specific torque in about 30 years. Not bad, but certainly not a doubling.

Demonspeed made another good point that I'll admit was probably unfair to overlook. The engines themselves do somewhat better torque-wise than they used to, yes, but some of the gearing they are going with nowadays is starting to get ridiculous. Now, I don't have as much experience with newer GMs as newer Fords...maybe GM does a better job...but Ford is a seriously bad offender when it comes to mating their engine characteristics with gearing and transmission shift points.

So maybe in this discussion with me complaining about torque, perhaps it would be more accurate to say that my issue is more with the overall powertrain package, and not so much the engine alone in a lot of newer cars.

You brought up my Alero (and yes, it is a 3.4). As a daily driver, it is not that bad of a powertrain. It only has 4 gears, but it drops down more eagerly when you step on it than a lot of the overly fuel economy minded newer 6 speeds I've driven. And yes, it may run out of breath at higher RPMs, and never come close to the 300hp a modern V6 will make, but as a daily driver/commuter, 99.9% of the time is spent at or below 2000 rpm. In 171k miles, I have literally only taken it to the redline 4 times.

Well, I've probably made myself look crazy enough for the night. I'm thinking of getting a diesel to replace the Olds when it dies. Anyone else think that would be a good fit for my driving style?