1970dartcustom
of the Moore clan
Is there a reliable calculator online, or another good method or something you guys recommend?
Is there a way without running the quarter mile?Weight of car in pounds x 197 then divide by ET cubed equals horsepower put to ground. Not sure how to type that better on here. Did that make sense?
DYNO-Rad, or
G-Tec Pro windshield mounted accelerometer.
Weight of car in pounds x 197 then divide by ET cubed equals horsepower put to ground. Not sure how to type that better on here. Did that make sense?
NO!Is there a way without running the quarter mile?
3200 lbs. car X's 197 = 630,400
ET cubed (or X's 3)
12 second ET X's 3 = 36
630,400 / 36 = HP
Except I got 175,011.
Dang, I missed it....
Yeah, IDK... The reason I posted this thread is because my Dad said that the setup we've installed in my Dart will make about 400 hp... Maybe a bit more...That's a pretty cool formula.
You got the back calculation for 1/8thM?
Oh, I seem to remember; 1/4M ET/1.57 = 1/8M et, So 11.8/1.57 = 7.5 does that seem right?
According to to that My 367 would be pushing 450hp. IDK aboout that....
Here's How I came to that; the Car went 7.92 in the 1/8th @ 2.2 60ft.
Suppose I got a traction aider to knock it down to 1.7-60ft. Would the car then go 7.92 less .5 = 7.42? Well let's say it did for a sec.,Then 7.42x1.57 = 11.65 in the qtr. Ok, well car is 3650 at the line. So your math says (3650x197)/ 11.65 cubed = 455 hp
Idk that seems like a stretch to me
But I tell you what; That formula might not apply to me, on account of I used the GearVendor to split gears on that. So I think I did that with 4.86s and the A-833 od with the GV. So the ratios were 3.09-2.41-1.67-1.30, and I trapped at 93mph.
So I used 4 ratios to get to 93 where most would use 2(automatic) or 3)stick-car)
but honestly, first gear was useless with 15/1 torque multiplication, I had to baby it out for quite a ways, hence the 2.2 60ft. I coulda probably got the same ET with 3.73s, which woulda been an 11.52 starter gear.
I cruised home at 65 =2116rpm in double O/D;how do you like that? heehee!
My conclusion is that the 4 ratios artificially enhanced my numbers so that the little 367 appeared to make 455 hp. And that is exactly what I was hoping for, when I built it the way I did.
There is no way my engine is making over 400/420. I have piloted 500hp 340s. and that is a raging beast, compared to my little sweetheart. But I might be able to reconcile the improvement in ET, to an approximate 8%increase in average hp during the run, due to the tighter gear splits.
In any case, I am very happy with her.
I bought a nearly new 1970Swinger 340 4-spd/3.55 in fall of 70. The next summer a bunch of us highschoolers boogied out to the track to see who was king of the hill.Well that totally stock little Dart couldn't do better that 14.4 at 98 in the qtr. I was a jubilant 17 year old.That car crossed the scales that day at 3310pounds.
In 2005, my 3650 pound, 68 Barracuda went 7.92 at 93 in the 1/8. I was a jubilant 51 year old.
Sorry OP, I got carried away again....
PS; 3310x197/14.4 cubed = 218 measly mal-nourished midget ponies; according to this formula.
323 gears in rear atm, and I have 2800 stall, and 27 diameter rear tires... the XE (extreme) 268 that I have is different than the 268 regular cam isn't it? Sigh, not something I know a ton about...273
Empirical numbers amassed by Mopar, back in the 70s. Bulletin book #40
OP.
The compression is definitely out of the ballpark for the 268 cam, but you have two things going for you; 1) the lightweight Dart , and 2)bigger cubes
Depending on your gears and TC, you could have a pretty good performer
So, by that equation, I'd have 415 hp...If your just looking for a guesstimation
I just base it off engines torque since it don't vary too much 1 to 1.5 lbs-ft per cubic inch.
Unless you have big roller cam very high CR big port heads and intake and exhaust to go along your probably making under 1.25:1 lbs-ft:cid so 1.15 is a nice conservative number for a decent street build. Eg. 360 x 1.15 equals 414 lbs-ft and generally an engine will be at 90% of its peak torque at peak hp so 373 lbs-ft so now you got to guesstimate where you engine hp will peak rpm wise. Say you figure 5500 now you just put that in the hp equation 373 x 5500 = 2,051,500 now divide by 5252 = 391 hp.
How did you get from 391 to 415? what did I miss?
You got headers on that thing?
What size exhaust, and free flowing?
With 9/1, I think it will be tough to crack 400, into street exhaust, with a 268.
To answer the compression question, Only if the 400 is some how magical to you.That 383 will be a beast in the 70Dart. Just wait until you drive it. You will have so much torque,it will scare you,lol
On the street the hp number is almost meaningless. Far better it is, to have 350 ftlbs at 2800, than to have 400hp at 5500 See with 3.23s 5500 is over 55mph at the top of first. But 2800 is 28mph, And if you are not familiar with 350 ftlbs at 28 mph, well you are close to finding out.You are gonna need 275s atta minimum, and you might as well buy a spare set.
You are gonna have fun! Pick your places and times carefully, and don't lose your cool.