RustyRatRod's Guide To Hot Rod Bliss
So called RV application, it's not really about more torque.
Yes it is, it’s all about the torque. The idea of the “RV” cam was help more easily move a heavier vehicle.
Torque is mainly based on displacement most engines will fall in between 1 to 1.45 lbs-ft per Cid, for most average street builds gonna be more like 1.1 - 1.25 lbs-ft per Cid, if your above 1.2 your doing good, the other mainly way is Volumetric efficiency (VE) how well your filling the cylinder in percentage so basically actual displacement being used which cam among other things effect this.
Not exactly correct ether. Never mind the values of torque you place on the displacements. For one it’s to general. Second, it’s misleading. The main focus of the “RV” cam is to increase the amount of air and fuel to make more power for more torque no matter the size of the engine. While a bigger engine “should” make more torque, this is not the actual case since depending on the year, some small blocks out power big blocks. During the dark years of the first introduced emissions standards that cut power dramatically during the era which spans from ‘72 on up for decades, even the big blocks were struggling to pull and push around small campers. Hence the introduction of the RV cam & as suggested by name, to help the RV vehicles.
While volumetric efficiency has a big roll in power production, it’s not the most easily fixed with OEM / stock parts. The OEM parts only work so well so you just increase the amount of time the valve is open to fill up the cylinder a little more.
Now for RV basically doesn't mean more torque but where torque is made,
Mostly very wrong. While the improved torque is the goal, the main idea of the RV cam’s rpm band is a few hundred rpm above the OEM cam which is sometimes as low as 600/700 rpm starting point. The RV cam is a few hundred above this mark, camshaft dependent.
And below you over estimate and push the camshaft as if it was pushing the rpm limits beyond its basic usage of description. This is so not the case.
Being the OE camshaft is very small in most cases never mind the big 114 LSA’s, the RV cam (normally) narrows the LSA, increases the duration a minor amount as well as the lift.
The rpm band of the cam barley increases any meaningful amount.
for a street car off idle to 3000 rpm is more important 'rv range' than 3000-5500 rpm street performance range. Most low power/truck type engines have a powerband of idle - 4500 rpm. It's hard overly increase power in the idle - 2500/3000 rpm range the trick with a street type performance engine is to increase the useable powerband from 4500 to 5000/5500 rpm without losing much and or small gain down low idle - 2500 rpm, higher stall deeper gears lighter car etc... Makes that less important. Efficiency is the third way, mainly low restriction intake and exhaust 'pumping loss' Cr there's others but those are the main. So it's about what's more important idle-3000 or 3000 - 5500 and the balance/compromise of the two.
In the above paragraph, your stretching the rpm range and unjustly assuming his targeted goal of what rpm he wants to perform in and the stretch is very wide and not a balance between a RV cam and a mild cam just above it but way beyond since you labeled the rpm range.
3K-5K? Seriously?!?!
And more direct to your question cam has the biggest role in this.
Above you listed that last.
“Now for RV basically doesn't mean more torque but where torque is made, ”
But it’s the cam keeping the valves open for more cylinder filling.
How is it not the cam that is important?
Changing the stall, gear ratio and tire size helps in a lot of areas just through math alone. Better torque release. You didn’t help the engine power.
Are you sure about what message your sending?
Do you even know what your talking about?
