HT4100 4.1, 4.5, 4.9 Discussion, What's so great about the 4.9 engine? in Cadillac Engine Technical Discussion; Is it better than the Northstar? Why? How much power/torque does it have? I'm just curious, really... I'd like to ...
The 4.9 is a standard two-valve pushrod engine. The NS is a four-valve OHC. The NS has higher peak torque and HP numbers, but they happen higher up in the revs. Displacement is a wash, as Cadillac was getting essentially the same 4.9 numbers out of the 4.5 in the Allante with tuned-port injection.
The 4.9 used throttle body injection or direct port on a cast manifold, the NS is essentially tuned port injected, with long runners.
4.9 used a single-coil electronic distributor, NS is fully electronic ignition with multiple coils.
4.9 was mated to the 4t60, NS always came on the 4t80. The 4t80 is a big part of handling that increased hp/torque on a heavy FWD car.
FWIW, I've heard that the 4.x series can be pushed to 300hp without much fuss, but the 4t60s couldn't handle the corresponding torque increase with acceptable longevity so it was never done.
I don't know about the NS, but the 4.x series of engines is an aluminum block with cast iron cylinder sleeves. So, the original 4.1 engine had larger sleeves installed with correspondingly larger pistons, and became the 4.5. Replacing the crank and rods on the 4.5 stroked it to 4.9.
And you're right, in this case "best" is DEFINATELY a subjective term.
As was just pointed out, the NS is quite a bit more powerful on paper but in the REAL world, the SOTP performance difference isn't huge. The reason is probably found in the power curve difference. The NS does produce more peak power but down in the "normal" rev range where most people are likely to spend MOST of their driving time, the two become much closer. I can't say for sure since I don't have the dyno charts to compare but, these kind of comparisons sometimes show the engine with LOWER peak power, actually has HIGHER power in the normal low to mid-range. I know several people that have both 4.9 and 4.6 engines that swear the 4.9 feels every bit as strong in most cases. But the specs don't lie. The bragging rights go to the NS.
In my experience, the true reason many people like the 4.9 better is it's reliability.
Is the HT-4100 the transverse 4.1? I know there was a longitudal 4.1 that may or may not have been the same engine.
I'm not sure what can be done to the 4t60. Cadillac modified the 440t4 in the Allante and called it the F7. The 4t65 is supposedly a better version of the 4t60, but (I think) the 4t65 and 4t80 both require powertrain control modules to manage the transaxle. I think (and I could be wrong) 4t60s are electronically shifted, but not electronically controlled.
Originally posted by ckucia Also, as the old adage goes "Horsepower sells cars, but torque wins races".
That makes me curious. Who would win a race between a 8.1 litre Suburban making 340 horses and I dont know how much torque, but more, and a 6.0 litre 345 hp Escalade with 380 ft-lbs torque? I'm not sure which would weigh more, cause the Suburban has more body and the Escalade has more heavy computers and gadgets.
Originally posted by 03EscaladeAWD That makes me curious. Who would win a race between a 8.1 litre Suburban making 340 horses and I dont know how much torque, but more, and a 6.0 litre 345 hp Escalade with 380 ft-lbs torque? I'm not sure which would weigh more, cause the Suburban has more body and the Escalade has more heavy computers and gadgets.
There's too many variables in that scenario to say for sure.
I dont understand why an engine with 4 valves in one cylinder has less power down low than an engine with 2 valves in one cylinder. It seems like there would be greater exhaust and intake flow which means more power. Someone educate me about this
Originally posted by 03EscaladeAWD I dont understand why an engine with 4 valves in one cylinder has less power down low than an engine with 2 valves in one cylinder. It seems like there would be greater exhaust and intake flow which means more power. Someone educate me about this