All else being the same, just wondering what affect going from a roughly 70 pound crank to a 40 pound crank would make performance wise(other than taking 30 pounds off the front of the car)

My steel 4 incher is close to 70 pounds, i know the callies and others come in a good bit less weight, and "trick" cranks can be 35-40 pounds.

Big "rev" difference???

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Big "rev" difference???

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Absolutely

How much ET might there be in knocking 30 pounds of weight off a crank...noticable??

I would think so but, you would definitly notice with no load on it
or even 1st and 2nd gear.

Does anybody make a 40 lb. 4" crank.........for Mopars?

Who makes a 70# 4" crank?

It would be hard to justify the gains of a reduced crank weight vs. the costs incurred. Lightweight BTW could compromise the integrity of the crank, especially in your application. To show any appreciable gains you'll need to reduce bearing diameters (and friction), throw-in some new rods and pistons/pins to take full advantage of the new crank.$$$ Better ways to go faster on a budget IMO. That might be a good new topic?

......and I think if they would have cut it down to 40 lbs. you'd notice too.

i wanna say the mopar 4 inch steel crank i have is like 68-69 pounds, and i believe the callies is like 12 pounds lighter.

callies makes a bigger buck crank(magnum i think)that might be even lighter than the dragonslayer.

Yep, Magnum...........then the Magnum XL

Be prepared to sell organs.

From Callies..the magnum XL series....


340 Mopar
* Stroke Range of 2.600 to 4.250
* 2.100 - 2.000 - 1.8885 Rod Journal Diameters
* 2.500 Main Diameter
* Weight Range of 35 lb. to 47 lb.


so if the 4.25 is 47, a 4 inch should be even less that that somewhat...a big diff over almost 70 pounds

If remember correctly my Dragonslayer was 52# before balancing so it will be lighter now as it did not need any metal added.

Scat Lightwieght and Ultra Light cranks come in in the mid to upper 40's, I think my lightweight wieghed 46 lbs after balancing. Light rods (Carillo) and pistons (Diamond) brought my bob weight down to around 1680. I was told that the biggest noticable difference would be in the 60 foot times.

I cant seem to find the weight on my crank anywhere,(mopar performance 4 inch steel) it was purchased right before calles started offering the dragonslayer for mopar 4 inch a few years ago, but i am almost positive it was either 68 or 69 pounds, way heavier than the other numbers being thrown around.

Next freshen i am definately going to put a much lighter crank in it, for sure.

Don, your SCAT 340 main crank is'nt anywhere near 70 lbs....

Callies 4" are usually in the 52-53 range

SCAT & K1 4" 2.50" mains in the 59 range, 360 mains around 61

SCAT offers 2 lightened versions of the 4", I sold Scott his, I think it was the mild lighten job & forget what it weighed before I shipped it.

Callies can do a sprint car lightening program on the Magnum stuff, & get them in the upper 30's with full aero wing style counterweights, star flange etc. Not cheap... & certainly not worth much ET at all in a high 9 sec combo.

Vacuum pump would be much better place to spend your $ than a light crank if you're looking for ET, especially with a light ring pack in your motor.

This has been most educational.

Don, when you pull the engine, bring it down.

We'll do it the old fashioned way.

A lightened crank will make the engine rev noticably faster (along with light pistons and rods). The crank in my 474 R3W9 motor was 4.375 stroke (More than even some big block strokers). The crank was 45 pounds with 340 mains. Rods were 618 Grams/6.300 and pistons were 430 grams / 4.155 bore. But that thing revved like crazy. I literally made a Baby cry when the car had the 3-1/2" FLOWMASTERS on it, and kids were constanly asking me to rev it when I was at the track.

My take on performance is that the engine will react faster and so it will flash the converter a little faster and hit the tires a little faster. So if you needed to make the CAR react a little faster for some reason it would be an advantage. I am sure the engine will accelerate the car a little faster but it would be in the hundredths. Not much. If you are making a lot of HP the car and crank are just going to accelerate fast no matter what. So a heavy crank in a motor / car that has a lot of HP is not going to be a disadvantage.

But I would have all 4 rod pins drilled no matter what, because this is bad weight and will not help crankshaft strength at all. I also would still go for lighter weight rods and pistons as long as the cost or strength are not to the extreme. Lighter pistons and rods are easier on the crank and them selves. Especially important if you want to turn higher RPM.

about a 99% chance ryan is right about the crank i have not weighing close to 70 like i said...the 1% is the fact i have a real good memory and read somewhere it was 68-69 pounds, and it stuck in my memory..that said, maybe the memory is going away with most everything else..54 is coming up mighty soon

I know that isnt the case With Ryan..he isnt old enough to have to even used his memory yet



Ron, great info, as usual..my pistons(CP'S)are super light, just over 400, and i think the compstar rods(6.300 are as well)....when i freshen it, it will be time for a crank anyhow, so whatever i get will be lighter than what i have, even if its just a slayer