JRick212

iTrader: (6)

These are a set of Ls6 heads that had been worked by Xtreme performance that I just bought off another member on here. I must say I am more than slightly dissappointed with my purchase.

xfactor_pitbulls

iTrader: (16)

It would be nice if the intake was flowed at 28" instead of 24". Thats kinda queer. Engines pull with more pressure than 28" to start with, 28" is just the standard. When you start looking at issues with turbulence, something lower than a standard pressure is misleading. Exhaust isnt super, but its pretty good for an N/A.

Brandon

JRick212

iTrader: (6)

I asked him about the 24" and he said something about when the heads start flowing more volume it has to be bumped down to 24" to compensate but the numbers there are adjusted for 28"

LedFut

For what he advertised, those flow numbers are crap.

JRick212

iTrader: (6)

This is what I was told they flowed

Lift: Intake: Exhaust:
.200 119 101
.400 246 187
.650 330 234

and I completely understand all the different variables from bench to bench but this is not even close

52172

iTrader: (2)

Similar thing happened to me I bought a set of cnc heads from a memeber that is now banned ls1powerhouse and he stated they flow 310 cfm@ .600 and they did not even flow 300 cfm @ .650! I ended up having them reworked, but I was pissed off and tried getting some money back and that never happened.

Ben R

You can convert flow @ 24" to flow @ 28". Here is what they flow at 28":

.100 - 69
.150 - 108
.200 - 140
.250 - 171
.300 - 200
.350 - 228
.400 - 250
.450 - 263
.500 - 274
.550 - 287
.600 - 294

That does reflect laminar flow, not turbulent. You need to have the heads re-flowed @ 28" to verify that they don't go turbulent.

52172

iTrader: (2)

now all of a sudden they look a lot better!

JRick212

iTrader: (6)

My guy is telling me that those numbers you are seeing are already converted to 28" for the intake even though it says 24" and how did you go about calculating those numbers?

Ben R

Square Root of (New Pressure / Old Pressure) x Old Flow = New Flow

Tony Mamo @ AFR

iTrader: (13)

You would multiply by exactly 1.08 to convert CFM at 24" to 28" figures (Benji's math was correct....I'm just saving you the time). I also question why the heads were only flowed at 24"....more than likely the bench used didn't have enough capacity to flow at 28". I would take those heads to another facility to back up those numbers. If the numbers you posted were already converted and they are reasonably backed up by another independent bench, there are alot of other head choices out there that would have obviously make a bunch more power. I wouldn't just bolt them on and hope for the best....do more investigating so you have all the facts and can make an informed decision on which direction to go.

If they do prove to be well off the mark (of what you expected), perhaps you have some recourse with the company you purchased them from....Good luck

Tony M.

JRick212

iTrader: (6)

I purchased them from a private party and I guess the old story goes....you get what you pay for. I am not sure of any other benches in my area so I will have to do some more reasearch.

But in the condition they are in I would never just put them on the car and hope for the best. It would be a waste of head gaskets and my time.

silverTA2002

iTrader: (1)

Maybe you could send them to TEA to get them reworked?

Depending on which cam you choose, the flow numbers might be sufficient though.

You could have heads flowing 500 cfm, but if the rest of your engine doesn't match, it won't make a difference.