AJ's Opinions; for the Teener Street guys. You know; zero to 60 and a decent cruise rpm.
that your 318 is making at most 140 psi, more likely it's closer to 130.
Let that sink in.
The factory 318 cam is about the smallest cam ever available to it.
Almost every bigger cam that you put into that thing is gonna drop the cylinder pressure.
Pressure is heat is torque is power. So
if you drop the pressure you automatically lose power in the range from idle to 3500rpm,
Based on what evidence, it just your speculation that torque is gonna drop off between 2000-3500 rpms with a mild cam.
Beside 318willruns car that contradicts what you are saying, here for the 100th time which you'll ignore any evidence to the contrary, is a low cr 318, Base is stock 2bbl with headers so base with manifolds would be even less torque and Mod 1 is 4bbl and fairly decent size cam xe262h and probably the biggest cam most would recommend on stock 318 long block and Mod 3 is spacer.
As you can see the mods made huge gains in low end torque with crap cr how could that be ?
And as you can see made huge power gains not just up high but down low also there's no reason it didn't gain across the entire range. 2000-5500+ rpm.
https://www.motortrend.com/articles/mopp-0312-318-long-block-bolt-ons/
| TORQUE SUPERFLOW 901 DYNO-TESTED AT WESTECH | | | |
| RPM | BASE | MOD 1 | MOD 2 |
| 2,000 | 292 | | |
| 2,500 | 287 | | |
| 3,000 | 287 | 338 | 336 |
| 3,500 | 272 | 335 | 340 |
| 4,000 | 248 | 326 | 330 |
| 4500 | 218 | 309 | 319 |
| 5,000 | 188 | 285 | 296 |
| 5,500 | | 250 | 258 |
| HORSEPOWER SUPERFLOW 901 DYNO-TESTED AT WESTECH | | | |
| RPM | BASE | MOD 1 | MOD 2 |
| 2,000 | 112 | | |
| 2,500 | 137 | | |
| 3,000 | 164 | 193 | 192 |
| 3,500 | 182 | 224 | 227 |
| 4,000 | 189 | 248 | 252 |
| 4,500 | 186 | 265 | 274 |
| 5,000 | 179 | 271 | 282 |
| 5,500 | | 262 | 270 |
the range that with your factory gears being from 2.73 to at most 3.23s, your engine is destined to be in, for 95% or more of it's life.
Let that sink in
Even if you had 3.23s, 3500rpm is ~32mph,
your bigger cam is gonna start adding power right about there, one hp atta time.
But, you gotta get to 32mph first, and your pressure is down, so it's gonna take looooooonger to get there!
IS THAT WHAT YOU WANT?
If it makes more average power basically over the useable rpm range, then yes.
Furthermore,
with the reduced cylinder pressure, it takes more throttle-opening to find the power to cruise with, so there is a very good chance that your fuel economy will suffer.
Furthermore,
with less pressure, getting off the line is gonna be lazier than with the stock cam. I repeat
IS THIS WHAT YOU WANT?
What are we talking 0 to a mile or two maybe even possibly a gain? it really just an assumption that gas mileage will automatically suffer.
Less pressure is the wrong way to go, and with a smog-era-teen, there is no easy/cheap way to get the pressure back.
My 318 friends;
listen to the Power junkie-clowns at your own peril.
Ideally more cr, cylinder pressure, V/P etc.. Is desired but sometimes you got to play the hand dealt to you.
Now then; Here's an example. Clowns take note, I said example.
Suppose your 2bbl-318 stalls at 2000rpm and at WOT makes 160 ftlbs there.
Seems excessively low to exaggerate your point, above says 292 tq with headers so maybe 275-280 tq @ 2000 rpm not over a 100 tq lower.
Thru first gear, and the thru the 2.73 gears that most of your cars will have, this multiplies to 1070 ftlbs into the rear axles, irrespective of what's happening inside the convertor. Remember that number.
Way off
Now pretend you install a 4bbl and a 2800 stall, so now your torque is up to 200 ftlbs/WOT, an increase of 25%. Let that sink in.
Now think about it, what cam could you install to match that, at 2800?
Now lets install 3.23s which will multiply that increase another 18.3%, so now, into the rear axles are going 1583 ftlbs,a total increase of
47.8%
Convertor only multiplies torque not power you got the same power at stall rpm going to the driveline.
You are gonna need to install a mechanical supercharger on top of your stock-cammed 318 to match that.
But wait, at 2800, the 4bbl is barely being tickled, and those 3.23s are adding their 18.3%, all the way to shift rpm.
ISN'T THIS WHAT YOU WANT?
Who cares about 20/30 hp at 5000rpm which with 2.73gears doesn't come around until 60 mph in first/101 in Second? Hmmmmmmmmmm?
Again power is increased over most if not all the powerband just not the top.
The truth is, that if you up-cam your 318, then you are gonna HAVE to do one of FOUR other things;
1) stall it up, or
2) gear it up, or
3) pressure it up,
You don't have but will make improvements
or
4) some combination of the above. just to get the low-rpm sub 3500rpm torque back.
So then, you might as well stall it up and gear it up, right from the start.
Based on speculation.
Over the last 55years, I've done it every one of those ways, and bar none, stall and gears is where to start, and if you can only afford one of those, let it be stall.
To the rest of you clowns that cannot read, you are not my target audience.
It would be good if people would add stall, gears and cr to a mild 318 but it's quite obvious most at least want to start with engine mods no matter how many threads you go into a try to brow beat them into doing the driveline first/only.
Go start your own thread.
We can do that and question your exaggeration of facts, like I said many times I agree with your basic premise it's when you twist unrealistic numbers to try to get your way, and refuse to modify your example's based on reality. And your true purpose discourage anyone from doing up a 318, since your recipe is not to lol.
Eg.. Like a cam automatically loses a ton of bottom end, zero gains in the mids and only gains up above where you'll never reach in the streets apparently no exception :)