Crower Billet Crankshaft?

[Diesel power]

I think that the stock crank with stock stroke can handle as much HP and TQ as a .250 stroker crank of any brand, when properly tuned to do so.

any input?

 

[Fingers]

Problem with the stroked motor is the rod length. Side loads the pistons and exaggerates the lull at the bottom half of the stroke. Also moves the max leverage point closer to TDC, which might be an advantage.

Still, more air and greater leverage on the crank means more potential for power.

Do you need a step by step why that is? Otherwise I will not bore you with details.

 

[TrentNell]

OK, bigger bore and longer stroke mean that you can get more air into a bigger area and for a longer period of time, giving you more overall air to compress, since there is more air to compress, there has to be more pressure, (since pressure is the driving force of the internal combustion engine!)


Can you show me that math on how more CI makes for lower cylinder psi ?

That just dosent jive with normal physics.

i think the debate is between cfm( a given amount of air per minute) and boost pressures needed to give the same amount of air ,wich would make or break the math wich is over my capabilities.

I think that the stock crank with stock stroke can handle as much HP and TQ as a .250 stroker crank of any brand, when properly tuned to do so.

any input?

i think time will tell to ealry to call for me .

 

[McRat]

I think that the stock crank with stock stroke can handle as much HP and TQ as a .250 stroker crank of any brand, when properly tuned to do so.

any input?

If it don't break it will, right?

Perhaps you should call Guy and get some input. He's always very helpful over the phone.

Wait, scratch that.

Lets say you have everything possible done to the engine for performance, and it tops out at 1200HP. Then you increase the displacement. You really think the power won't increase? Why did Dodge and Ford up their displacement? You should have called them and stopped them, it would have saved them millions.

 

[Redbone]

or compare volumetric efficiency at there given peak rpm's .

Kind of. I should added "and their relative cylinder pressures".

 

[McRat]

From the best I can tell, the stock dmax cam and unported heads is about 80% volumetric efficiency at 3000rpm. This is based on datalogs and how much air "should" be going into the engine.

 

[Redbone]

That's interesting Pat, do you recall VE at peak torque (1600 RPM?). I thought with the charger it might sustain closer to 100% at the higher revs.

 

[McRat]

It was a long time ago, I'll have to find my notes.

What I did was use a factory tune, factory airbox, and read the MAF flow, boost, and baro with the truck in park at 3000rpm. Think it made 1-3PSI boost? Then I calculated out what it SHOULD be consuming (disp/2*rpm), versus what the MAF said. Seems it was 80%. We don't have a throttle, and since there is little backpressure or boost, it should be match up if you had 100% VE.

 

[McRat]

The problem with boosted air, is that it's hot, and makes the math less reliable.

 

[Redbone]

The problem with boosted air, is that it's hot, and makes the math less reliable.

Stupid unreliable math.

 

[Stingpuller]

Nice tech talk

I think some forget about internal friction on these motors. Ring pack(radial tension),windage(possible use of a vacuume pump), Hone on the bore(goes with rings),acc. on front of engine. The heads are key as is the cam. I think there is some on the table in all parts on these motors. I stil think for the money a ICE COOLED drinkof NOS is the ticket. Man I can't wait for race season. Jeff

 

[Stingpuller]

Motors

Did any one else notice the nitrous setup on Jess's truck in the new diesel power? Finally getting some trick stuff in these diesel's. Jeff

 

[Diesel power]

If it don't break it will, right?

Perhaps you should call Guy and get some input. He's always very helpful over the phone.

Wait, scratch that.

Lets say you have everything possible done to the engine for performance, and it tops out at 1200HP. Then you increase the displacement. You really think the power won't increase? Why did Dodge and Ford up their displacement? You should have called them and stopped them, it would have saved them millions.

You really know so much........

They increased CI because they could get more TQ with less fuel consumed and get better emissions at the same time! For them it's a Win-Win, obviously total opposite of what a True engine builder would have done for all out drag racing.

Again you say" everything possible done to the engine" and i say No it wont make more power because since "everything possible is done to the engine"
It cant flow more air, so you cant make more power by just increaseing displacement! Displacement does not equal airflow. Maybe Guy should hone you in on a few minor details.......:rofl:

 

[Redbone]

I think some forget about internal friction on these motors. Ring pack(radial tension),windage(possible use of a vacuume pump), Hone on the bore(goes with rings),acc. on front of engine. The heads are key as is the cam.

I crunched through some rough BSFC numbers a week or so ago and came up with an overall efficiency of around 40% or thereabouts. There's LOTS left once someone figures out how to minimize the parasitic losses.

 

[Diesel power]

I think some forget about internal friction on these motors. Ring pack(radial tension),windage(possible use of a vacuume pump), Hone on the bore(goes with rings),acc. on front of engine. The heads are key as is the cam. I think there is some on the table in all parts on these motors. I stil think for the money a ICE COOLED drinkof NOS is the ticket. Man I can't wait for race season. Jeff

I agree nitrous IS the ticket

 

[Diesel power]

I crunched through some rough BSFC numbers a week or so ago and came up with an overall efficiency of around 40% or thereabouts. There's LOTS left once someone figures out how to minimize the parasitic losses.

You are absolute, the average on a gasser is about 25-30% and a diesel is about 40%, and can be bested once one realizes how important parasitic drag and effiecient burn come into play.

 

[malibu795]

hmmm
HP is how much work can be done
TQ is how fast said work can be done.


how come a 300/520 motor can out accel a 300/300 motor

if TQ means nothing in drag racing then a 800hp BBC should keep up wiht a 800hp diesel...... but is dont..... why?


tq get work done

strokeing naturally increase tq perioed.

 

[dmaxlover]

Lets say you have everything possible done to the engine for performance, and it tops out at 1200HP. Then you increase the displacement. You really think the power won't increase? Why did Dodge and Ford up their displacement? You should have called them and stopped them, it would have saved them millions.

Now there's a good question. The difference between 7.1L and 6.6L is about 8%. Are you saying by only changing the displacement will yield 8% more power? I think power will increase, but not enough to matter. I do know that if the original fueling is used the egts will be lower under similar circumstances.

Now if we take our 8% larger displacement engine and add fuel above what was used in the 6.6L until the same egt's are achieved, what is our power output going to look like?

 

[ZeroGravity58]

Now there's a good question. The difference between 7.1L and 6.6L is about 8%. Are you saying by only changing the displacement will yield 8% more power? I think power will increase, but not enough to matter. I do know that if the original fueling is used the egts will be lower under similar circumstances.

Now if we take our 8% larger displacement engine and add fuel above what was used in the 6.6L until the same egt's are achieved, what is our power output going to look like?

I know gassers are diffrent but.....I dynoed a 350 SBC i had built, then switched everything to a 383 SBC. Without changing anything the torque curve on the 383 was alot flatter instead of being really peaky like a 350 torque curve. I also picked up more torque and HP. Now i know this is diffrent between gas a diesel. I posted this just wondering if everything is the same would/could it also flatten out the D-max torque curve? Id post the dyno sheets if i could find them but its been a few years ago.

 

[McRat]

hmmm
HP is how much work can be done
TQ is how fast said work can be done.


how come a 300/520 motor can out accel a 300/300 motor

if TQ means nothing in drag racing then a 800hp BBC should keep up wiht a 800hp diesel...... but is dont..... why?


tq get work done

strokeing naturally increase tq perioed.

It's area under the curve in the racing RPM range that does it. Our Dmaxes have relatively flat HP curves in the racing RPM range. Gas engines usually don't.

Here's a primitive example since I don't have dyno sheets in front of me.

Curve  Gas   Diesel
Start   300hp  400hp
Middle  500hp  500hp
Shift   400hp  450hp

The gasser has 400 avg HP while racing through a gear. The diesel has 450 avg HP going through a gear.

It doesn't matter what the specific RPM's are, hence the torque is irrelevant.

When tuning, you try to maximize the area under the curve, instead of looking for a peak number. With us, the torque peak isn't even in the racing RPM range.

Tuning for torque is pointless, since for us, it's falling the whole time. I read something on another board that I found comical, that you accelerate based on the torque curve. Uh, our stock trucks peak at 1600rpm, then falls sharply. Anyone think their truck accelerates harder at 1600 than 2500? RIIGGHTTT, but it was a Dodge board, and that kinda thinking (or lack) is common.