If the magazine say so, it must be true

 

why are we talking about fords any way. i thought that web site was junkyardwars.com sorry just found this one funny

 

i have a question for you guys.

what are the unported and ported head flow numbers for

ls1
ls2
ls7

and can you include port sizes before and after porting. thank you. -bill

 

i think car craft or hot rod has a library of head flow numbers. good luck

 

 

tack on 100cfm for the LS7 port @ .600

 

They flow that much? hmmm
my LT1 don't have anything on that

 

352 @ .600, they can easily do 360cfm in stock form..... and make power. Now ported versions flowing 400cfm can make less power but win the race on the flow bench.

Bret

 

can you guys help me with the validity of what this guy says?

Take a minute to walk a mile in my shoes you might understand why myself and all the other competent and experienced engine builders are leary about just about 98% of the junk posted on automotive oriented forums. I will include some factual information below from my shop and a few others regarding LS2 cylinder head flow data. I have spent over 150-200 HRS on doing LS2 cylinder head flow analysis alone. Most shops invest about 50-100 hours developing a particular head flow model and program.


this is his post

On certain low valve angle racing heads (less than 12°) you could run 350+ FPS @ 28.0" H20 and not see TQ/HP losses, but the overall port geometry would have to be just about perfect to keep the a/f mixture in suspension and attached to that specific shape throughout the port. On a street/strip small block head like ours, when you start to go over 300 FPS (20.5" pitot pressure at 28.0" flow bench testing depression) you can watch as it will start to induce a premature sonic choke condition on the flow bench with the pitot tube right around the area of the SSR apex. The curtain area should be the choke point, or in other words the curtain area should be where you observe peak local airspeed. If you observe a peak local airspeed anywhere other than the curtain area, you will likely have a problematic cylinder head. When you are flow testing at 28.0" H20, the higher the pitot velocity pressure is above 28" (350 FPS at the pitot tube) and the greater that distance is away from the curtain area, the more power you will lose. Something else that will hinder power is to have a specific area of very high velocity near the SSR apex, or a side of the of the port wall that is in excess of 350 FPS coupled with a significantly slower downstream velocity, that velocity differential will cause fuel separation and will significantly increase your odds of having a sonic choke condition.

There is also a low limit local airspeed that is commonly accepted to be true. This is 240 FPS or 13.14" pitot velocity press when flow testing at 28.0" H20. When you start to go below 240 FPS, you will lose power on any head, especially in the lower RPM range at increased throttle angle. Piston speed and rod/stroke ratio also have an effect on the way a port responds at low RPM increasing throttle angle. On a small stroke motor like ours with a relatively large rod/stroke ratio, that 240 FPS will be way too slow and that motor will lose torque. Torque is obviously important at low RPM part throttle situations.

Also when comparing valve lift to port velocity, low lift flow (meaning anything below 1/2 of the total lift) is relatively unimportant. Think about the valve events in a motor for a moment. From the point when the valve first lifts off its seat until it reaches mid lift, the piston is either going the wrong way (rising towards the top of the cylinder) or it is experiencing dwell near TDC. The piston doesn't begin to move away from the combustion chamber with enough speed to substantially lower the pressure in the cylinder until the valve is nearly halfway open. High lift flow and a relatively low velocity port will make the most power and perform the best on the street or drag strip.




how much if that is true? thanks.

 

More like from Gods lips to my ears. Believe them everytime.

 

That's very interesting information. Don't follow the technology but a couple shops around here are getting $8K+ for LS7 head, cam and header packages and making 600 rwhp. Or so they say that's what they get and the heads have "extensive porting."

More "gods lips to my ears" and I believe them every time.

 

looks like in need FORD GT heads to compete with you guys.

btw a stock gt500 with CAI,oversize throttle body, whipple low drag charger and stock everything else is making 810rwhp. go to whipple to check it out. they saved 60 hp with low drag technology. the gt 500 has ~FORD GT ports.

 

More interesting information. I've seen a bunch of LTx cars with stock hyperutetic pistons not do very well at all when the boost went over 6psi. To make 800 rwhp you need some pretty serious boost and out of curiousity I did a little surfing to see if the engine at least had forged pistons as the LS7 engine doesn't.

The very first site on Googel was: http://home.nycap.rr.com/tritonlemon/

The next website on Google talked about the class action lawsuite over cracking intake manifolds.

Never did find out for sure if the Ford GT had forged pistons but found a site that did say they had power forged rods and forged crank. My assumption is they probably are not forged but don't know for sure.

Did however find it a bit amusing the two most popular websites implied a few customers are exactly jumping for joy with Ford. I'm sure Chevy has a few of those running around also but it wasn't exactly what I was expecting.

 

All 03-04 Cobras, Ford GT's, and the new GT500's have forged pistons, mainly because they are all supercharged from the factory.

 

In that case, I'd bet a few of those puppies will probably boot scoot pretty good. The lemon website caught me off guard as I wasn't expecting that to be the first one to pop up. Had to chuckle to myself over that one.

I know Bret follows the engine masters stuff pretty close but Ford whipped some real butt this year at that event with a 434ci limit. If the rumors of a new LS based NASCAR engine are true, that may change in the near future.

But hey...I'd love to have two or three of those Ford GT's sitting in my garage in case one of them got dirty or something. Next to a couple Z06's. Then there is a yaht, a real babe or two to go with the yaht. etc. Not kidding……. this time anyway.