4.8L Daily/tow rig naturally aspirated upgrades...cam?
03-05-2016, 07:17 AM
#13
10 Second Club
iTrader: (18)
A quick Google search netted these results - LR4 9.5:1 CR, L20 8.8:1 CR. The combustion chamber on the 799/243 heads used on the newer engines is slightly larger, not enough to lose .7 points of CR. So possibly different head gaskets were employed as well.
03-08-2016, 02:08 PM
#17
TECH Enthusiast
Different engines entirely, but I put Tri-Ys/Long Tubes on several 350s and the difference was night and day even down in the low-midrange. On my Ram with the 5.7 it was also night and day difference.
03-08-2016, 02:26 PM
#18
The whole hp vs torque thing is misunderstood by a lot of people. Think about it like this, there is no such thing as horsepower, there is only torque and an rpm associated with that torque. "High HP Race" engines have high torque at high rpm, "towing" engines have high torque at low rpm. Both could produce the same amount of torque, but just at different rpms. Power is when you multiple torque by rpm.
The ONLY WAY to increase torque at a given rpm is to:
1.) increase engine size (bore and stroke, etc.)
2.) increase engine volumetric efficiency (VE) (cam, heads/intake/exhaust, VVT-which isn't on your truck, supercharging)
3.) increase oxygen density into the engine (turbo, blower, nitrous)
If you don't want to to do number 1 or number 3, then your only option is to spin the engine faster, throw on some better heads, a cam swap, or more likely a combination of all 3. All these mods will likely increase torque of the engine across the powerband if spec'd properly. You can install a looser torque converter so you skip over the low portion of the powerband and don't spend any time there, giving the feel of more power.
You didn't mention what size tires you have, but if they are stock size or larger I would do a gear swap to 4.56 as this will give you a big increase in tractive effort at the wheels for little cost. Its ok to let the 4.8 rev, it doesn't need to lug around at 1500rpm on the highway. After that would be a tune, then cam and headers.
The ONLY WAY to increase torque at a given rpm is to:
1.) increase engine size (bore and stroke, etc.)
2.) increase engine volumetric efficiency (VE) (cam, heads/intake/exhaust, VVT-which isn't on your truck, supercharging)
3.) increase oxygen density into the engine (turbo, blower, nitrous)
If you don't want to to do number 1 or number 3, then your only option is to spin the engine faster, throw on some better heads, a cam swap, or more likely a combination of all 3. All these mods will likely increase torque of the engine across the powerband if spec'd properly. You can install a looser torque converter so you skip over the low portion of the powerband and don't spend any time there, giving the feel of more power.
You didn't mention what size tires you have, but if they are stock size or larger I would do a gear swap to 4.56 as this will give you a big increase in tractive effort at the wheels for little cost. Its ok to let the 4.8 rev, it doesn't need to lug around at 1500rpm on the highway. After that would be a tune, then cam and headers.
03-08-2016, 02:50 PM
#20
Yep, do 4.56s and a tune and call it a day. I don't think you will ever be happy with the engine power from the 4.8 without a power adder, so its easier to let the gears work for you. As a bonus your gas mileage may get better as well with a more suited towing gear.