Guess I'm missing something on the graph.

Intake valve lift------------- .200 .300 .400 .450 .500 .550 .600 .650 .700
stock intake---------------- 156 226 276 294 310 324 332 332 308
LPE CNC intake 4.065" bore* 156 228 280 300 320 336 346 352 340
LPE CNC intake 4.125" bore* 158 230 282 302 322 340 350 358 344

 

So Spin, do you think a 226/236 on a 115LSA would work great with an excellent (LT's, X-pipe, free-flowing CB) exhaust system in place?

 

LPE's numbers arent stock so those we are clear about.

Next fact: any given head flows more on a bigger bore than a small bore.

Next fact: The second row of flow numbers you have there in your graph are for a 4.125" bore. The stock test numbers were from a 4.125" bore.The stock LS3 head on a 4.065" or a 4" is not 332 at .600 lift. It flows less on smaller bores. On a 4" it flows 320cfm at .600

I dont know how else to say it.

 

As I said above there are a lot of variables.

What lobe will the 226 duration be ground on? Cam motion? Comp cams XE,XER,LSK,XFI?

What lobe type for the exhaust side's 236?

Why such a big split? Why a 115lsa? It will peak too high for the stock manifold.

What I think is that you should buy a cam from a tuner that posted results for a cam and not try to guess for yourself. I would go with a 226/230 114 before that cam.

The best specs for a small cam were 224/228 112 LSA
The tuner didnt say what lobe type they were.
Synergy motorsports.

 

Comp XE

High lift lobes

Drivability

I think I see what you're saying.

 

High lift AND long duration would be a bad mix on the exhaust side.

A big split makes for a longer duration exhaust lobe and therefore more overlap=worse driveability. You have that one backwards.

The wide LSA moves the power band up. The duration you have there would best be served with a 113+1 or a 114+2.

 

Yup, I did have that backwards. I always forget that the heads installed on the motor is not the same as a flow bench, high lift will not act like it does on the flow bench (which is a constant flow).

Thanks man. I'll run this by my tuner when the time comes.

 

The stock flow numbers posted by someone else from our web site are indeed for a 4.065 bore. The ported numbers show the flow for the stock 4.065 bore and for a 4.125" bore.

The flow data, along with images of the sectioned heads, can be seen here:

http://www.lingenfelter.com/Merchant...Category_Code=

 

Another soul saved by spinmonster... I will give you a call tomorrow spin, hope your God father voice has improved, remove the cotton *****..

 

Richard@WCCH Did the flow testing of the new L92 heads.

I just finished flow testing a new stock L92 head. All I can says is…….WOW! What a nice part.
I’d like to publicly thank StreetnStrip for the opportunity to test this head.
The test head has casting number 5364. Here’s the tale of the tape……..

4.030” test bore
Lift ___.100 _.150_.200_.250_.300 _.350 _.400 _.450 _.500 _.550 _.600 _.650_.700_.750
#1 Int. 74.9 109.4 154.4 193.5 225.3 252.8 274.6 292.7 308.8 321.0 328.7 326.6 310.0 316.6
#1 Exh. 63.6 97.9 126.1 148.7 162.3 178.6 189.6 197.6 205.5 210.7 214.6 217.8 221.2 223.5
The intake was tested with a radius plate and the exhaust was tested with a 2 ½” stub pipe.

4.155” test bore
Lift ___.100 _.150_.200_.250_.300 _.350 _.400 _.450 _.500 _.550 _.600 _.650_.700_.750
#1 Int. 73.8 108.7 153.2 192.6 225.2 253.6 277.0 296.7 313.0 326.0 335.8 326.9 327.3 317.1
#1 Exh.61.1 97.9 125.7 148.1 162.0 179.5 191.8 200.1 205.9 213.3 218.4 220.9 221.9 223.2
The intake was tested with a radius plate and the exhaust was tested with a 2 ½” stub pipe.

His is firsthand testing on his flowbench. I think 332 is possible for the 4.065 bore at peak. The variance isnt as much as I thought. Also reports are that the 823 version doesnt flow as well from rougher casting. I'll stand corrected.

Do actual installs support the gains seen on the flowbench? Or would you say that a 275cc runner makes these a stroker head when ported? What cam have you paired them up with and what were the results?

 

please LPE...port the exhaust side only of the LS3 head...throw in your GT2-3 cam and give us some #'s

 

Spin, your right about the results but reasoning is not so good. I know this is the internet and "midlift" flow numbers are important here but there are a lot of engines that don't agree with you that they are so important. In fact I've had some testing sessions where changing the valves in a clyinder head killed the .300" lift number 25cfm and it gained 10 ft lbs thru the whole TQ curve.... that's why I say in the real world engines don't agree with the internet.

I don't want to pick on you here but please don't elaborate like this on how you think the world works in cylinder heads. It's just misleading to others, but then again this is the internet. You are right that flow numbers aren't everything, but in the paragraph above you are stating that midlift numbers are everything, and now you are saying flow numbers don't mean anything. Which one is it?

My big problem with your statements is about your thinking on velocity.... You do not have to slow the air down to increase the flow volume (CFM), in fact when you have the same size orifice and you increase volume (CFM) thru that orifice your velocity will increase. It also goes by a different name, discharge coef (DC). The more volume you can move thru a set area the higher the DC, or the same volume moving thru a smaller area means higher DC, both are good when done properly. Now a problem that can happen is when you increase the flow in the LS3/LS7 heads and do not pay attention to the DC, velocity and port shape it will not work better.

Now on the exhaust.... YOU DO NOT WANT TO BUILD THE AIRSPEED! In fact doing the exact opposite is what works. When you crack the exhaust valve and it sees extremely high cylinder pressures that combined with the heat cannot even be related to any flow bench out there (in excess of 200" of H2O) velocity is not hard to get and in fact makes itself a problem. The reason the LS3/LS7 head with the intake valve to exhaust valve ratio at 73% and how small the exhaust venturi (smallest part of the exhaust port) is, it all goes back to the DC and the laws of physics tell us that at 28" of H2O (what we use on a flow bench) you can only move a max of 146 cfm per sqin, so if you have a small hole you can only move so much air. LS3/LS7 heads are patterned after the best NA designs in racing like Cup and Pro Stock which run intake and exhaust valves at that 73% ratio range. Scary thing is some Cup exhaust ports can move 300cfm! thru the same 1.600" valve size these street heads use. I've only seen 280cfm thru a LS exhaust though due to port/casting limitations.

I wouldn't chase the compression ratio with these motors, they produce such good VE% that the motors can easily get detonation at compression ratios that cathedral port heads can handle. Mostly it's a balance between the cam and how you "fix" the head, let's just say a lot of conventional internet thinking and chasing flow numbers is not the best way to go.

Keep learnin!

Bret Bauer

 

 

Both positions boil down to the same thing, which is that you have to do the setup with a tuner who has researched the optimal combo and has proven real-world results. That is why Spin mentions the Cartek example. Similarly, SSStroker brings up his personal example of a change that, theoretically, should not work, yet did.

The problem with these discussions, is that they can easily devlove into an argument over specific cases which disprove another poster's assertion. In the grand scheme of things, both Spin and SS are correct in what they are trying to convey, which is that there is a base of theory out there to support good results (such is not only focusing on peak flow numbers, because midlift is more important everyday), and that the art is in the combo and the tuning.

The take-away should be that throwing a bunch of name-brand parts together in your garage is not going to get you the same result as the max-effort number aftermarket head mfr. X, whose head you used, obtained and uses in advertising. A perfect example is one related to one of the heads discussed in this thread, which way back posted some pretty amazing numbers. I happen to know the gentleman (also discussed herein), who did the testing associated with validating the performance of said cylinder head. The bottom line is that it took countless small details, trial and error of combinations, and one month of dyno testing to achieve that published number. That same gentleman applied that knowledge and much more to my setup, with the end result being 484/435 on a LS2 with ported 243 heads using stock sized valves and a little 224/228 cam. These numbers are through 4.10 gears, and using Valero california pump gas, so they would equate to being well in excess of 500 had this been a max effort hail mary dyno number.

Charlie got there by not ignoring a single detail, right down to blueprinting the springs, matching injectors, match-porting the FAST, and about 100 other things the average guy who throws AFR205 heads on his car in his garage, will never do. And this was after 1 month of research into the optimal cam, ususing VE spreadhseets and all the rest. The point is, use a reputed tuner, don't try to cut corners or try to learn it yourself, and don't skimp on costs. Do it right the first time and it will cost you a lot less in the long run.

 

Well, in case anyone cares, there is more to it than that:

The LS3 camshaft has a 5.758 percent increase in lift from 0.521-inches to 0.551-inches and camshaft timing was changed for increased power with the higher intake valve lift. The intake lobe profile comes from the 2002-2004 LS6 camshaft.

The exhaust valve lift and lobe profile is the same as the LS2, which came from the 2001 LS6 camshaft.

Lobe separation was increased a degree over the LS2 cam.

 

I ended up with a 227/235 LSL Comp lobe on a 114+2. Perfect cam for this LS3 setup, bolt-ons and what I was looking for. After tuning it, drivability is almost stock and the car makes excellent torque & power.

Thanks Patrick G & Vengeance.

 

TTRotary...

My problem was the explaination of the results... I usually don't argue with those unless the testing was flawed.

Jimmy,

Man I've done some work to fix cars with cams running those lobes... not a fan of them and neither was the rest of the valvetrain!

Bret

 

Hey bro , the best thing you can do is call john beck in houston tx the guys some of the fastest intakes that will blow your mind. I t will make a ton more than the plastic intake from wilson. Wilson is a nice peice ,but you will be more pleased with his stuff. Fact go to youtube and type in beck intake you can see some of his stuff in action. his number is 281-446-1621

 

Sorry for the LATE (3 year) response.

Really? I've had this cam in my motor now for 13K miles, no issues whatsoever. I'll change the springs in 2000 miles but other than that I'm not sure where you're coming from.

 

How do you like that cam? Comp sells an off the shelf LSr grind that is 227/235 113+4, I thought about getting it.