Howdy,

I have been looking for flow numbers on heads. TEA, MTI, MMS, LGM, Cartek, GM CNC, and anyone else who does heads....

I don't want to see a scan of a graph, I was actually looking for the actual numbers. Now, of course the fact that flow benches vary doesn't make this a scientific test. But, I think some folks would like to see if one heads flows better in other areas. Here, let me start it with the GM CNC heads posted by SDPC...

'02 CNC LS6 cylinder heads as tested on a SF1020 at 28" H2O on a 4.030" bore plate.

Lift Int Exh
.100 65 58
.200 138 113
.300 214 157
.400 261 191
.500 292 210
.525 295 212
.550 285 214
.600 282 218

If you have numbers, post em....

 

GTP Stage 2 flow numbers....

.205 lift 166.2
.303 lift 224.8
.401 lift 270.7
.454 lift 288.9
.502 lift 301.3
.524 lift 304.7

These are 99 and newer style 5.7 LS1 heads.

 

TEA 5.7 Stage II
Lift Int Ex
.100" 65 58
.200" 135 114
.300" 202 160
.400" 251 200
.500" 285 225
.600" 296 240

TEA 5.3 Stage II
Lift Int Ex
.100" 65 58
.200" 135 112
.300" 202 170
.400" 251 209
.500" 285 239
.600" 296 255

 

Thanks guys...

Everybody else, step up...

 

I have numbers from my 3 sets of heads I've owned, and it seems if anything CANT be compared, its the flow numbers.

Now, if we all want to send the heads to the same shop and have them all tested on the same bench, that might be a good test. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

 

No, jmx you are absolutely right. Unless things are tested on the same bench, an exact side by side test would be meaningless.

But, I guess what I was hoping was to look at the flow numbers and look at them across the spectrum.

If you see that head x flows a constant 5 cfm more than head y. Then there may be that much variance on the flowbench, and the heads are probably just alike. But if its 20 cfm more at .300 but dead even at .500 then I would want to look at what the diff was.

I am just trying to get the some numbers together. Anyone have numbers on MTI heads especially a Stage II LS6 head?

Like I said, I am more interested in the overall curve, and the port volume. I don't care if any head flows 350CFM @.700 that does nothing for me.

 

.300 - 214
.350 - 241
.400 - 265
.450 - 280
.500 - 294
.550 - 310

Speedaholic Stage2+ Heads from jperacing.com Ported By Brent Singh

 

Now if we could get the port sizes and what size chambers all those heads have we would have something. Smaller chambers will usually cut down on flow if the head wasn't designed with them, i.e. milling the head. Smaller ports with less flow (to a point) but high velocity will make more torque. If we are looking at 215cc, 235cc and 270cc ports and the small ones are only down 15-20cfm, those are the ones im going to pick for a 5.7L (346 cube) engine.

Flow numbers are only half of it.

 

Don't forget that port velocity is key to making good power. I have seen plenty of "big flow" heads that didn't make the numbers of heads with smaller numbers that had a higher swirl rate. The key to making a GEN 3 head flow great is to make sure the intake port is V shaped when ported.

This allows the smaller floor of the port to keep velocity speeds up at low RPMS, which keeps torque up, and at higher rpms the air starts raising off the floor of the port where it is wider and needs volume.

 

does the bore adapter diameter make a lot of difference on CFM? I have seen some on a 4.03, but mine were done on a 3.90.

 

Sliver,

Yes, a 3.90 bore adapter is correct to use, BUT bear in mind that flowbenches are good for comparisons from head to head with the same bench but may not bear a direct reflection of same readings universely meaning that if I flow X amount of cfm at my shop, someone elses flow bench may be off as much as 20 cfm higher or lower. I have seen this first hand. The thing that bothers me alot about flow benches is that there supposed to be a fine tunned 13,000.00 dollar + scientific instrument that shouldn't vary by 2 cfm's of being flow tested from the USA to China, they should have the same flow result, but that dosen't seem to be a fact. I have used my flow bench for 4 years now and our flow numbers + ported flow improvement ratings are perfectly on par with our horsepower improvements which is 1 cfm is worth .27 horsepower reqaurdless of where the flow started to where it ended up, it's all universal at that point. 2 years ago when I started he LS1 porting, I scoured Magazines and Tech articals from the school of Sam looking at other professional posted average flow ratings for the LS1 heads and my flowbench is within 1-2 cfm's per data point of advertised numbers accurate, I spot check heads from time to time and always re-check the bench callibration and we are considered "dead on" to GM's advertised flow numbers.
Joe.

 

Don't have my entire flow sheet numbers but peak numbers are

317 @ .550 lift intake
210 @ .550 lift exhaust

hope to see ~440 rwhp once I get Ls1 Edit and some low 11's at 12X full weight.

 

Jrod, i have ported my own heads and for several other people also. The valvejob and valves are untouched, my port volume is 210cc on intakes,81cc on exhaust, heads are 5.7 Ls1:
Int..200"=144cfm
.300"=208
.400"=250
.450"=270
.470"=276
.500"=278
.550"=267
.600"=267
Exh: .200"=100cfm
.300"=134
.400"=173
.450"=180
.500"=190
.550"=195
.600"=200
All flow tests at 28" on a 4.0" bore, on my Superflow 600 bench.

 

Thnaks for the reply's everyone...

Also SStrokerAce, you bring up some valid points. I think we can all agree upon the fact that if you just hog out a head, then sure, you will see big flow numbers. But port velocity suffers, and so does power.

I don't have all the heads avaliable to me, or I would offer to get measure the volumes on each, flow them, and post the results. As it is, I am hindered by only being able to compile the information provided by individuals.

My goal in doing this was to examine some of the many offerings out there currently. Honestly I would love to see GMHTP or some other magazine, or someone get all the head together and run them all on the same bench. Then have some independant expert on the subject evaluate the work on each of the heads.

Then we could have a valid side by side un-biased opinion. I don't see much chance of that happening. So, I' am doing my best to gather some of this together.

In looking at the raw data, you can't get too hung up on the numbers. As we all know benches can vary. So, rather than looking at "this head flow more than that head" we need to look a bit deeper.

Look at the heads, lets take the GM CNC vs the GTP stage II. Look overall, lets assume one bench is off, and try to equalize the ports at one point so that we can try to remove some of the bench variation. But we need to go both direction both up and down

Is the GTP bench off by 10CFM? well it could be, or the heads could flow 10cfm better all the way across. Even if it is 10cfm off the heads still flow 18cfm better @ .200. But if it is 10 off the other way. then you are seeing 38 CFM more @ .200. Plus more flow across the board.

Ok, lets look at the TEA heads. They are down pretty much across the board except at high lift (.600) which most cmashafts don't reach. But I guess we could assume that between the -7 @.500 and the +14 @.600 that flow at your camshaft's max lift would be better than the CNC head.

Again,the TEA bench could be on the conservative side. The GM CNC head on their bench could flow 10Cfm less on it. In which cas ethe TEA heads would outflow them across the board.

Like I said, this wasn't about the raw numbers, since they are meaningless. But, I think it can show you that even with error between two benches that certain heads will show where they perform at. Even if you have a bench variation of 5 - 10 CFM a 15 CFM bump from one head to another can show problems, or great potential over the competition.

Like I said, lets not get too hung up on one data point or whatever. Lets just try to see where in the flow curve one head seems to have a better "curve"...

I am using the GM CNC head as my reference.

<img src="http://www.z06vette.com/gallery/data/1067headflow.jpg" alt=" - " />

<small>[ September 17, 2002, 08:23 AM: Message edited by: J-Rod ]</small>

 

My heads are 2.02/1.57 5.3 heads.
I only have intake and exhaust numbers at .600 lift:
intake: 298cfm @ .600 lift
exhaust: 227cfm @ .600 lift (no stack or pipe)
10.8:1 compression

Cheers,
Chris

 

GTP LS1 I/E
.100 65.8/51.0
.200 135.9/103.8
.300 200.8/141.5
.400 244.1/176.2
.500 278.3/190.4
.550 291.5/194.1
.600 285.0/198.3
.650 291.4/202.7

I/E Ratio @ .550=70%
235cc I port

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by jmX:
<strong>I have numbers from my 3 sets of heads I've owned, and it seems if anything CANT be compared, its the flow numbers.

Now, if we all want to send the heads to the same shop and have them all tested on the same bench, that might be a good test. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Head flow numbers definitely have to be taken with a grain of salt when comparing them. We've seen heads that claim 300+ CFM that only did 258 CFM when thrown on the same bench that our CNC head guy uses. We've also seen heads that claim way less then other heads claim perform better on the engine dyno. Numbers definitely don't tell all!

 

I can offer up that my head work is tested before and after porting, and my stock numbers match ARE article in GM Hi tech and Westechs flow data in Chevy Hi perf magazines article for stock numbers. This in my eyes validates my numbers to be good for comparisons. I look at after vs. before for gains. I can also tell you guys are getting "happy" exhaust numbers, LS1 ports do not flow 230 to 240 cfm at .550" lift. These happy benches say stock port flows 200 to 210 at same lift and they dont flow that much air either. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

 

You are right.. LS1 heads flow around 180CFM on the ex stock, but I know for fact on the same bench that flow 180CFM, that the head porter can get 245CFM. However he keeps most of his stuff at 225-230. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

This is a fun trend lets keep it up.

<small>[ September 17, 2002, 11:15 PM: Message edited by: Phil ]</small>

 

Well, that was one thing I was wondering about. I tried to use the GM CNC head as a basline, because I had hoped that it might be somewhat accurate.

LS1derful. If you have a stock LS1 or LS6 flow sheet, please post it. I'd like to show those as well.

Anyhow, my curiosity was arroused by the fact that the LS6 cnc are ahead of the TEA's on intake, but far behind on exhaust.

Do you think 210 @ .550 on the exhaust for the GM CNC is accurate?

If those numbers were representative of what the heads actually did, they would respond best to two distinctly different camshafts.

Any other thoughts???