whos got desktop dyno?

[WayFast84]

I need some help


I want to see the difference between a 400sbc with l31 vortec heads(stock flow numbers) a edelbrock performer rpm intake, holley 750cfm carb

and one with xe284 and one with xe262

thanks
matt

[Tru2Chevy]

Here ya go:

XE 262:
http://www.njfboa.org/JustinImages/xe262.jpg

XE 284:
http://www.njfboa.org/JustinImages/xe284.jpg

- Justin

[Tsar]

these guys! (http://www.proracingsim.com/purchasejac2.htm)

[WayFast84]

why does the xe262 make so much more tq?

[NJSPEEDER]

lower lift using the same draw volume = higher intake velocities. that helps to create torque.
the peak number with the smaller cam does look better, but it is falling off hard from 3000 on. when you look at dyno or simulation curves, ignore peak numbers. they are very misleading and don't account for where the useful power band it or how the car will be able to use the power.

[BonzoHansen]

...ignore peak numbers...Now where is the fun in that?

[NJSPEEDER]

dyno's and peak numbers are fun to brag about to your import owning friends, but somewhat useless for basing the actual performance of a car. so in high school they may actually be of some use to wayfast. lol

[WayFast84]

i guess neither cam is good for this then.. huh?

[j0n]

methinks that first engine combo would be awesome for a truck...400+ lb-ft of torque from idle to 4000+ rpms

[unstable bob gable]

What would the power level be with NAWZ? :)

[NJSPEEDER]

i guess neither cam is good for this then.. huh?

you are basing these simulations on stock flow numbers. you said you were going to get them ported. if you are leaving them stock you shoudl look into an XE274 or similar cam, that would be better for stock. the factory ports aren't going to flow nearly enough to take proper advntage of what the XE284 has to offer.
justin, if you care to run the simulation again using a 10% increase in the flow numbers you can show wayfast a better picture of how the cam will react with properly prepped heads.

[Tru2Chevy]

Here's the xe284 with the same specs as above and a 10% increase in head flow numbers (intake and exhaust sides):

http://www.njfboa.org/JustinImages/xe284plus10.jpg

There are some nice gains above 3000 RPM from the head porting....

- Justin