Tests like this are what sets this channel a part from the others. Pitting two top shelf (for most guys) heads against each other and letting the cards fall where they may. No sponsors getting in the way, just an honest flow of information from Richard to the world. Thank you.
I have a Superflow flow bench with the wet option that uses fluorescent dyed liquid that shows flow direction coming out of the intake valve into the combustion chamber. Many two valve closed chamber heads have swirl flow (hemi heads have tumble flow unless the intake port is asymetrical). At different valve openings the swirl pattern can move around in the combustion chamber. If the swirl pattern moves over the spark plug it can cool the spark plug and change or clench the combustion rate. Also the ingnition spark intensity is dependent on the temperature of the sparkplug because electron transport needed to generate a spark is temperture dependent and related to the Edison Effect (see WIKI - Thermonic Emission). The wet flow bench can give an idea where that's possibly occurring. The intake port contour directly before the intake valve is extremely critical. This is why two different heads with identical airflow numbers can have completly different performance.
I think this is it. You have to remember that Gasoline kind of burns/expands like shit and extracting the most work out of it is highly dependent on a lot of factors.
Hello Richard… great video. Im glad that you used a more less stock LS3 for the testing. Shows more real world results for the average person that doesn’t have a monster cubed engine. I’m guessing it’s minor differences in combustion chamber shape design, plus the minor differences in port volume between the heads explains why the AFR shines.
From what I've read, Tony Mamo was the lead head specialist at AFR, and his manual porting designs of their cast heads made it into these castings. So effectively the AFRs are cast versions of Tony's manual porting techniques. When Tony left to create his own company, Mamo Motorsports, he's spent a lot of time porting the TFS260s also. From forum posts, it appears he sells more ported TFS. IIRC, his ported TFS have better CoD than off the shelf AFR.
I would check the short side radius on the intake side of both heads. I suspect the AFR's are probably a little straighter (less of a curve). If that's not the case, I'd then look at the 'pinch point' where the boss for the intake valve goes through the port. Might be slightly smaller on the Trick Flow.
So were talking about a 2% increase (approx). Maybe valve spacing , or subtile differences in the cnc work . The AFR heads are obviously moving more air at higher RPM. But again, barely 2% difference. And that is about the difference in intake port volume. So, math and stuff.....
My thought is that if everything else is the same, the AFR with the slightly more port volume made slightly more power. That was the only difference between the heads.
Love how any time I think of a comparison or want to learn something, Richard already has a video out on it haha great guy, keep up the great work and one day I’ll have my motor built
AFR did their homework. A couple years ago the talk was about wet flow (maybe from edelbrock). Maybe AFR did a little more work with wet flow in mind. Or maybe that 69cc is actually 66. Maybe the port length is a little shorter moving the powerband up just the little bit to carry torque and hp higher.
While the flow bench numbers may be nearly the same the port shapes (intake and exhaust) on the AFR heads may be working better with the intake and exhaust manifolds. It certainly appears they are flowing more air at higher RPM with the only difference being tested on an engine with intake and exhaust systems.
LS3's are over valved relative to their bore size, not that its bad. That is why porting them and not killing torque below 4k rpm is tricky. So I would say the difference is really due to where the engine is making power, relative to each heads runner size. It's just able to pull better on the AFR and achieve higher port energy with it. The TFS may catch up or surpass with more displacement, compression, or rpm if it were made available, but port energy, average port speeds, cannot be discounted or ignored.
I read an article years ago about AFR heads and there's more to heads than just air flow. AFR heads also tries to maximize air flow while maintaining a good balance of air flow speed and turbulence to better mix the air and fuel. That works great for carburetor engines, but I don't know about fuel injection. I can understand it working the same way if the fuel has to go in through the intake valve, but direct injection has the fuel injection straight into the cylinder and the heads only flow air. With your history and knowledge does that make sense from the testing you have done.
I'd like to know what valves and hardware the heads both have. That modest power difference could perhaps be explained If the valve/retainer package on the AFR heads is a fair bit lighter than the parts on the TFS heads. Theoretically, any work put into compressing the valvesprings should be given back to the cam when the springs expand again on the closing ramp. This would be totally correct except for the bit of heating effect on the spring when compressed/strained - and also the inertial forces of the valve trying to hang open (newtons first law). The differences are small, but again, if the AFR valve package is notably lighter, I think it could explain what we're seeing here. It jives the effect only becomes notable at higher RPM.
There are many reasons one could think of. Most are already stated here. Shrouding if the valve has been move to solve this. Spring rates, better valve to cam geometry, Cam spec'd for the head/combo, better exhaust alignment. Flow is not everything. Port design/alignment to it's counterpart makes the best combo. The day and time you ran the dyno? Was the atmospheric pressure the same. Water grains and so on. Push rod length to the exact will give a little. Shit the list goes on. But for the $$$'s spent on heads the stock ones sent to Texas speed would be my pick.
Maybe the difference in power was the camshaft favored the AFR with the exhaust split. Perhaps TFS did not need as much exhaust split. AFR Flow numbers: LIft Value Intake CFM Exhaust flow CFM .200 159 112 .300 234 158 .400 293 207 .500 336 235 .600 366 248 .700 384 255 TFS Flow numbers: Lift Value Intake Flow CFM Exhaust Flow CFM .200" 146 113 .300" 231 171 .400" 294 215 .500" 334 240 .600" 363 252 .700" 382 258 AFR also has 13 more cfm on intake @.200".
I had time to think about it. I believe the .100 and .200 lift points of the afr had more flow enough to let the camshaft act slightly bigger due to more effective flow at low lifts. This increased power at higher rpm. I'm also curious as to the intake port entry vs the manifold.
Alloy disperses heat sink better than iron which equals more timing but maybe one alloy head disperses better than the other alloy head. Interesting to see the timing graph overlay between the two alloy heads cheers Richy from 🇦🇺
Thank you for another informative video. You know what I want to see... how much power can you make with the crate or junkyard 360 magnum, stock heads and a turbo! turbo magnum! turbo magnum! turbo magnum!
The afr head has better flow most likely because of valve angle they have less flow restrictions because they have less shrouding when the intake vale pops off the seat.
Since both heads have very similar measurable flow numbers the difference in power has to be related to port swirl and atomization. Both heads have the same chamber cc but are there any differences in shape to alter the flame front? 🤔🤔🤔
Great vid, Thanks sir. I don’t know why AFR is better but I will give all this vid viewer an advice: Do not buy TFS in any case I tried them on 2 cars and always rocker arms are moving from their location, intake valve not open and making a big misfire in the engine. Bad quality heads unfortunately.
Valve cut can make a difference. I've read the 823 heads had a 3 angle valve grind and the 821 had 2 angle. I'm not sure how true it is. You know how the internet is. Valve angles do make a difference for flow.
Which way does the 2-3 cfm flow difference go between the AFR & TFS? Is it always in favor of the AFR? A 2-3 cfm difference at low lifts (and therefore flow rates) can help significantly. But anyway, for a stock displacement LS3, aftermarket heads are not a good value in terms of Dollar per HP. 40 HP (max) gained per $2600 for a set of heads. That's $65/hp. The best value is to spend $5-600 on a cam and springs, and you get 50-70 HP.
Would like to see a similar test on a SBF between TFS 170 11R and AFR 165 Renegade. Maybe a 331, about 220 degree duration cam and Performer RPM intake.
Yes, I'm sure that they would be close to each other, but is one actually superior or the other? Is one better on the low end? High rpm? And people do actually still build these, as well as 350 Chevys, 383 Mopars, etc. If these don't interest you, then stick with the LS, Gen III Hemis, or Coyotes. I happen to like all of them.
You can see that the limiting factor in these tests was the intake manifold, limiting these heads at around 300 to 310cfm at the 600 lift point. I would say the AFR with the slightly bigger volume has the extra material taken away at the punch allowing for a slightly better line of sight to the valve from the manifold, the extra port volume will also contribute to those heads being able to have that extra 100rpm to peak.
I feel the Trickflow is stalling, air speed is definitely a factor here in my opinion, short turn radius ill bet the afr heads short turn is layed back alot further than the Trickflow, either that or minimal cross section pinch being the culprit
I would honestly like to see the differences of a ported head and cam on the ford fiesta's 1.6 ecoboost, because there have been zero documented runs with a head and cam 1.6 eco boost.
Hey brother, I work for a performance shop and one question I’m super curious about and we’ve never had a back to back test is Frankenstein’s and Brodix heads in the mix. That would be awesome if you could do that. Thank you sir for all your hard work!
Frankesteins wont out flow brodix heads not in mid flow not in max flow. but would be nice to see i got a set of brodix heads bx 300 , we had frakinestiens befor changing over
@@richardholdener1727 Facts we switch over because we felt the mid range was soft for a 434 tall deck lsx twin 85mm turbos. pick up big time everywhere on the brodix heads.
Valves, tulip or back cut variances or valve job variances. Port shape or finish, where are those 5 cc'?, chamber shape, finish, afr lends itself to better swirl and tumble or better quench for better fuel mixture/atomization.
Richard, do you have any comparable data or anecdotal information how the AFR and TFS heads compare to stock heads that have been CNC Ported? For example the TSP CNC porting on LS3 heads.
Was the valve spring package the same? The AFR may have been slightly better at controlling valves (bounce at the seat). Maybe it had lighter valves and retainers or a little more appropriate spring for the combination.
@@cedricwilson2055 Where do I say float? i didn't say valve float, I said bounce. Clearly the spring wasn't in full float but a proper spring/valve comb is worth power on a like for like situation.
Your talking less than 1% in power between those 2 heads on that combination at different times of the day. I've seen the density altitude change by over 1000 feet in less than an hour, dozens of times at the race track. Just for giggles, I looked this afternoon when I first saw the post and again 10 minutes ago. The D.A.was 3164 feet above sea level at 1pm and its now 4481 feet. That alone is worth nearly 4% in power.
What about oil pressure? I don’t remember this being mentioned but my thought is maybe if the way the oil flows through the heads is different there may be slightly more resistance. Or is that a long shot? Possibly the same idea with coolant through the heads. More heat, less power.
did you try swapping the valves? touch up the valve jobs valve job analysis valve analysis stem coatings. finish, materiel, shape? TI option Inconel option common sizes chamber analysis' any differences in guide materiel, seat materiel? (like for HD) velocities? which? blower I've wondered why not a canted valve head with a semi rotated chamber cheers
This is great information, this will be one of my last mods after I go blower/boost for better efficiency and not cranking up psi. I wonder how much of an increase we will see if this was running on 10 psi, you think it will be similar 40hp gain or a lot more?
Johnprince got it. Moving the valves closer to center for more valve relief. Saw this on a head porting chanel. ls3's like valve relief! Looks like you used the stock intake for low rpm. Is the valve pic showing the afr head intake valve moved over the centerline between the two valves?
Looking back at your previous LS3 tests, it seems the baseline was down on power. After valve jobbing LS heads with some heat cycles, there's always a couple valves not sealing 100 percent
Is it valve angle? I believe the TFS allows a little larger cam due to altered valve angle. With that in mind, if you ran the largest cam you could in each would the tfs then come out on top? I’m curious how my ported LS3 heads would stack up to these two. As usual we have answered a question and have new questions.
I wonder if it has something to do with one these heads Possibly having a swirl ramp? I don't know much about LS3 heads but I know 5.3 heads have a swirl ramp
