Science has nothing to do with it. All it takes is a fat wallet.
What would it take to make 1.44 lbs-ft per cid ?
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I want to see him build a 273/292 like Jim's. it seams he posted the dyno sheet and pointed out the lack of torque.
Maybe he can do better.
Not saying I could but 1.14 lbs-ft per cid ain't too high that would be a 408 making 465 lbs-ft.
Was kind of the point of the thread to see what it takes to build more in the 1.35-1.45 lbs-ft per cid.
33IMP
Well-Known Member
E85....and a turbo.
You guys know me and horsepower numbers but my old Econo W2 headed 408 ran 9.82 at 2750-2800 pounds on BP93 pump gas. .520 lift Racer Brown solid lifter cam, 2.02 valve W2 heads flowing 300cfm, ported W2 Victor intake, 750 Holley, 4.88 gears, I think it had my CRT 727 transmission at the time. This engine had lots of rum to grow. None of that NoS crap needed.
This 500 ish hp 10:1 355 Chevy with tunnel ram only made 448 lbs-ft, 1.26 lbs-ft per cid. Obviously it don't mean much in itself, it did gain over the single plane and dual plane and 10 more cid and a little more cr would help but just bolting on a tunnel is still far off the 1.35-1.45 tq:cid in this case.
This stock 6.0l LS with cam and headers made 514 @ 5,900 rpm and 493 lbs-ft @ 4,400 rpm so 1.35 lbs-ft per cid. Cam was only a 228/230 on 112 lsa so obviously the stock heads and intake work well a bump in cr probably would get closer to 1.40 tq:cid. Similar peak power and rpm as the 371 and 408 but like the 371 under the curve is a bit shy.
At 6:50
At 6:50
Interesting topic. I think it's more interesting than hp/cut in because you can always head flow and rpm your way to higher power.
I don't have a ton to add here. I would ask, what fundamentally yields more torque? Do that.
I would also ask, what fundamentally reduces parasitic losses. Do that.
It may be that there's a sweet spot where you get better efficiency between bore stroke and displacement. Put another way, I'd bet that st the extremes you get reduced tq/cu in. So a 273 or a 572 might make lower tq/cu in.
Stating the obvious here, but a cam and intake matched to both make peak torque at the same rpm seems like a big fundamental one to get right.
I don't have a ton to add here. I would ask, what fundamentally yields more torque? Do that.
I would also ask, what fundamentally reduces parasitic losses. Do that.
It may be that there's a sweet spot where you get better efficiency between bore stroke and displacement. Put another way, I'd bet that st the extremes you get reduced tq/cu in. So a 273 or a 572 might make lower tq/cu in.
Stating the obvious here, but a cam and intake matched to both make peak torque at the same rpm seems like a big fundamental one to get right.
Basically torque is per powerstroke (1revolution) & hp is all the powerstrokes over time (rpm).
So more torque is basically how much air/fuel can be crammed in per powerstroke (VE%) and how efficiently you can turn that potential energy into rotational force.
Obviously we basically know all the ingredients to do a decent job 1.15-1.30 tq:cid, and vaguely know above that, obviously getting the velocity right (VE%) plays a big role, but beside knowing that don't seem like to many can give a less abstract idea of what it takes velocity wise and other aspects to be more in the 1.35-1.45 tq:cid club.
And I get it for the most part it doesn't matter, cause it's generally easier and probably cheaper to build a less efficient larger engine for a given hp & rpm.
The cheap and easy way? Procharger all the way.
Tom
Tom
It takes more than just money.
Dan the man
Well-Known Member
Question: If a decent running 365 can make 450 horsepower which works out to 1.2329 horsepower per cubic inch. 1.440 x 365 = 525 horsepower. That's difference of 0.2071 horsepower per cubic inch of displacement. Did I calculate this correctly? If so, I don't understand why it would be so expensive to make the additional 0.2071 horsepower per cubic inch. I'm sure that I'm not understanding something here, but it seems to me that the extra power could be had with more compression and cam
Scody21
Just send it
Just to throw a curveball into this, 1963 technology, 3 liter or 183 inches making 500 HP at 10k rpm and 295 TQ at 8500. 12.5 to 1 comp, 112 leaded gas, 2-1.25 inlet and 2-1.16 exhaust valves per wet liner hole, gear driven dual cams on a 102 centerline, pushing flat tappets, mechanical injected, dry sump. Rebuilt every 20 hours. 2.73 HP per inch…. Takes money and the right combo of parts to make the power level your asking for…
Were talking peak torque per cid, it's a measure of efficiency.
If you look at average built 360's they make around 380 lbs-ft to about 450 lbs-ft that's 1.06-1.25 lbs-ft per cid, All out max effort engines can reach about 1.67 lbs-ft:cid, if you getting 1.20-1.30 lbs-ft your doing pretty good. Above 1.35 lbs-ft per cid is a fairly high goal.
Dan the man
Well-Known Member
Basically when you modify your car your re engineering your car.
Plus 1.61 lbs-ft per cid.
Dan the man
Well-Known Member
When talking torque per cid were basically talking efficiency so for a given hp per cid say 400 hp 318, a less efficient (tq:cid) 318 engine is gonna need more rpms to make 400 hp cause it's making less torque per revolution, where a more efficient 318 can make the 400 hp at a lower rpms cause it's making more torque per revolution but for the most part both are able to make the 400 hp.
So like in this example in this thread if you could make a 515 hp 365 make 1.44 lbs-ft per cid it should make the power at the same/similar rpms as the 515 hp (1.29 lbs-ft per cid) 408.
I'm not a coyote engine expert. In fact I know very little about them. But I do know they make good specific output. From the tiny bit of searching I've done, the 2020 mustang 5.0 coyote makes 1.39 ft-lb/cu in.
I find this interesting but unless anyone has anything specific to do to get there it's only bench racing.
I know for me, this stuff is out of reach right now and I'll be happy if I can just get my car running and driving. I'd be very happy with a 475ft lb 4" stroke engine.
I find this interesting but unless anyone has anything specific to do to get there it's only bench racing.
I know for me, this stuff is out of reach right now and I'll be happy if I can just get my car running and driving. I'd be very happy with a 475ft lb 4" stroke engine.
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