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Is it better than the Northstar? Why? How much power/torque does it have? I'm just curious, really... I'd like to know more about it...
 

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"Better" is a subjective term. The Northstar is a fantastic engine, but its also about 10 years newer - a lot happens in engine design in a decade.

Some numbers:

1991 4.9
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1997 NS
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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.
 

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Great post :thumbsup:
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.
 

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Also, as the old adage goes "Horsepower sells cars, but torque wins races". The torque figures are pretty darned close on the two engines in the useable rpm band.

4.9s are also relatively cheaper, although there are zero performance parts out there.

I do love that N* engine though...
 

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the 4.9 is basically a HT-4100? the HT4100 was such a bad engine.... how did they work out all the problems for the 4.9?

could the 4t80 tranny be mated to a 4.9, or not? or is there a way to make the 4t60 more heavy duty?
 

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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.
 

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ckucia said:
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.
 

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03EscaladeAWD said:
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.
 

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:histeric: :rofl: :histeric:
 

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n00b question - the 4.9 is carburated, correct?
 

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Port fuel injected!
 

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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
 

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03EscaladeAWD said:
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
Reason = GM

'nuff said
 

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03EscaladeAWD said:
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
Do you have comparable figures for the 4.9 and the 4.6 at various RPM? I don't know what they are, but I suspect the difference at a given low RPM is pretty minor.

Think of an engine as an air pump. The 4.9 can process 4.9 litres of air per revolution. The Northstar can do 4.6 litres. At a slow speed, like 1RPM, the amount of air that has to flow through the valves in order to move 4.6 or 4.9 l of air is pretty minimal. However, at say 1000rpm, the 4.9 is flowing 4900 litres of air per minute and the N* 4600. As RPMs continue to increase, the total amount of air flowing through the engine (and thus through the valves) will reach the limit of the capacity of the valves. It is here that multivalve engines have an advantage - they increase the upper limit of how much air can flow into the cylinder, thus they also increase the effective operating RPM of the engine. The valves are essentially the "doorway" into and out of the cylinder.

In other words, at low RPMs, the engine has excess flow capacity through the valves, so having more valves offers relatively little advantage - the engine isn't using the capacity it has.

Of course, all things aren't equal. There are all kinds of other considerations including the intake runner characteristics, exhaust characteristics, plus the control and ignition systems, compression, bore, stroke, etc. I'd suspect the 4.9 to have more bottom end torque mostly because it has a slight displacement edge over the Northstar. i.e. its a bigger engine (although only slightly). Because of the other design characteristics, the engineers can build the engine to meet a given specification. The 4.x engines were designed to have lots of torque on the low end and to have an overall lower operating RPM than the Northstar. That's the way they're supposed to be by design.

There are several reasons why Cadillac put pushrod V8s in their vehicles. A big one is that the technology for a OHC multivalve V8 hadn't yet matured enough to be able to deliver the performance, longevity, and quiet operation that Cadillac owners expect. Pushrod engines have been made for so many years now, that they're nearly bulletproof. The N* is quite a technologically advanced engine, especially in the details, but its also a complicated engine. Also, its easier to make an engine quiet at low RPMs, so an engine that has lots of low-end torque doesn't need to rev high to pull around a heavy car. Cadillacs haven't had a stick since the 40's or 50's until recently, so running a parasitic automatic transmission (with lots of slip to give smooth shifts) was also likely a design consideration.

All in all the 4.1/4.5/4.9 engines did exactly what they were supposed to do - haul around (relatively) heavy, sedate, FWD cars quietly, with decent performance, and respectable fuel economy.
 

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Discussion Starter #17
Panther said:
Could the 4t80 tranny be mated to a 4.9, or not? or is there a way to make the 4t60 more heavy duty?
Can anyone answer Panther's question? I'm interested in knowing the answer too...
 

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Sal Collaziano said:
Can anyone answer Panther's question? I'm interested in knowing the answer too...
I don't know if they will physically bolt up, but that isn't the big issue.

The 4t80e is fully electronic controlled. All 4t80e controls are integrated into the ECM (Engine Control Module) to the extent that GM renamed it the PCM (Powertrain Control Module). As far as I know, you can't make the transaxle portion standalone, and since the 4t80e only came with the Northstar, the 4.9 wouldn't be compatible, at least for street use. Even if you could get an early PCM that ran a speed/density EFI system (early N*s were speed/density, later were MAF) and were able to tweak around the engine management incompatibility via changing fuel pressure, etc., you'd need a custom ignition, as 4.9s used a distributor-based ignition, while N*s used a coil pack.

I'm sure if you could figure out all the above issues, physically bolting the transaxle is easy enough. If it isn't a direct-bolt, then an adapter plate could be fabricated without much trouble. Depending on the clearances, a different torque converter might be required.

The 4t60 is essentially a beefed up 440t4. You can get transgo kits for them. If the trans is high-mileage, than a rebuild is prudent. Here are shift kits
http://www.bulkpart.com/cgi-bin/miva?Merchant2/merchant.mv+Screen=CTGY&Store_Code=MDITP&Category_Code=440T4sk

Here are rebuild kits and hard parts
http://www.bulkpart.com/cgi-bin/miva?Merchant2/merchant.mv+Screen=CTGY&Store_Code=MDITP&Category_Code=440T4

Here's a place that has transaxle controllers (standalone, I presume) for the 4t80e (among others)
http://www.transmissionadapters.com/Pricing.htm

BTW, the 440t4 and 4t60 are electronically controlled, to an extent. ECM signals the torque converter lockup and there are solenoids that manage the shifts. However, with those its more a matter of the ECM telling the transaxle "shift now", and the transaxle uses its own mechanical modulator to determine the shift characteristic. With the 4t80e, the PCM is able manage the characteristics of the shift electronically. I don't know the details, but its more complicated than the half-dozen relays and a vacuum modulator in the 440t4/4t60.
 

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Discussion Starter #19
Thank you. So the best bet would be to work on the transmission that comes with the 4.9.. I doubt I'll ever take on something like that - but this is good information to know...
 

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ckucia said:
Do you have comparable figures for the 4.9 and the 4.6 at various RPM? I don't know what they are, but I suspect the difference at a given low RPM is pretty minor.

Think of an engine as an air pump. The 4.9 can process 4.9 litres of air per revolution. The Northstar can do 4.6 litres. At a slow speed, like 1RPM, the amount of air that has to flow through the valves in order to move 4.6 or 4.9 l of air is pretty minimal. However, at say 1000rpm, the 4.9 is flowing 4900 litres of air per minute and the N* 4600. As RPMs continue to increase, the total amount of air flowing through the engine (and thus through the valves) will reach the limit of the capacity of the valves. It is here that multivalve engines have an advantage - they increase the upper limit of how much air can flow into the cylinder, thus they also increase the effective operating RPM of the engine. The valves are essentially the "doorway" into and out of the cylinder.

In other words, at low RPMs, the engine has excess flow capacity through the valves, so having more valves offers relatively little advantage - the engine isn't using the capacity it has.

Of course, all things aren't equal. There are all kinds of other considerations including the intake runner characteristics, exhaust characteristics, plus the control and ignition systems, compression, bore, stroke, etc. I'd suspect the 4.9 to have more bottom end torque mostly because it has a slight displacement edge over the Northstar. i.e. its a bigger engine (although only slightly). Because of the other design characteristics, the engineers can build the engine to meet a given specification. The 4.x engines were designed to have lots of torque on the low end and to have an overall lower operating RPM than the Northstar. That's the way they're supposed to be by design.

There are several reasons why Cadillac put pushrod V8s in their vehicles. A big one is that the technology for a OHC multivalve V8 hadn't yet matured enough to be able to deliver the performance, longevity, and quiet operation that Cadillac owners expect. Pushrod engines have been made for so many years now, that they're nearly bulletproof. The N* is quite a technologically advanced engine, especially in the details, but its also a complicated engine. Also, its easier to make an engine quiet at low RPMs, so an engine that has lots of low-end torque doesn't need to rev high to pull around a heavy car. Cadillacs haven't had a stick since the 40's or 50's until recently, so running a parasitic automatic transmission (with lots of slip to give smooth shifts) was also likely a design consideration.

All in all the 4.1/4.5/4.9 engines did exactly what they were supposed to do - haul around (relatively) heavy, sedate, FWD cars quietly, with decent performance, and respectable fuel economy.
Thanks for the info. So the one big reason that the 4.9 has a slight advantage down low is because of displacement. It has more air flowing through thier valves even though it has less valves. So if a pushrod Northstar was made, same displacement, same everything, then the 4 valve northstar would have more horsepower down low. (But only very slightly) All these factors are probably shadowed in performance by the different weights of Cadillacs from the early 90s to present day Cadillacs.
 
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