AFR Renegades SBF heads - Over-hyped or underrated?

[Music] so [Music] hi david beizard here and you are watching power tech 10. give me a few minutes of your time and i'll give you the benefit of not only 50 years of race-winning engine building experience but also 30 years of successfully teaching it at university [Music] level [Music] so what's the subject of this episode of paratech 10. well if you're a ford fan you're gonna like this it's a rundown on a very successful and very functional small block ford cylinder head ever wonder why this series is called power tact 10 i sometimes ask myself that but there was an original sound reason my original idea was to have a 10 minute short video to highlight certain important but rarely talked about items in performance well it turns out two things one i have way more of these uh things to talk about and two and they take up more than ten minutes right so i really should name it power tech 30 because that's nearer it but anyway that's beside the point what's our subject for today it's a ford head a small port ford head from afr now i do have some experience with this from way back unfortunately i can't remember much of it and uh so i thought i'd start from scratch here and look at their current one but i had great expectations because it was one of the top performing heads along with one from edelbrock and one from dart so what have they done that may be different now well let's get into that because this head turns out to be something a little more special than you might think first let's take a look at the basic cylinder head stripped of his hardware we can see from this that it's fully cnc ported head now you may look inside the ports and think well that's a bit of a coarse finish there can they truly justify that i don't know if you can see it here but you probably can hear the the screwdriver going over it well i have cleaned up some of these heads to uh just make the finish an emery roll finish and two things are evident one it has almost no effect on the flow and i'm talking about just a surface finish change here not a shape change and two it has no effect on the horsepower either and i think or i'm sure if you actually polish those ports you'd probably lose a bit of power my guess is that these ridges here in some way shape or form act like not so good golf ball dimples in other words they're better than a flat port but not quite as good as golf ball right and their golf ball finish is very expensive to do anyway there we go so 165 cc intake port 70 cc exhaust 1.9 inch intake valve 1.6 exhaust the valves are very good here let me show you they are a lightweight design flat back because that's what the port likes but the best virtue is their 5 16 stem or or 8 millimeter right and as such they are very light we'll get into that in a moment i'll show you the weight difference between that and here's the exhaust tulip shaped on the back and this is usually a form that works well nice radius on the front there and the spring for it and we'll go through the details on the spring but i can tell you now my experience with afr heads is that their hardware is always top quality i once men remember saying to rick i don't understand how you make any profit on your heads your valves and springs must cost twice what everybody else's do and he i think his response was along the line off he says well you know quality does cost and i said yes but your prices aren't any higher than anybody else's of any consequence that is so anyway that's the basic uh casting there let me tell you what we're going to do with it essentially i'm doing this flow test is only part of a whole test if the final part is going to be when we put it on an engine and put it on the diner and put these heads on the dyno right and we are going to test with two intake manifolds one a l brock rpm air gap performer which is a very good head for sorry a very good manifold for heads like this and two a triple carb triple two barrel carburetor manifold which when you first look at it the first impression you will get is nothing is going to flow very well through there but my partner in crime on this project jack sane at walters engines has ported this manifold extensively so it does flow pretty well and what it will do it flows well enough for us to make a useful comparison between the effectiveness of that intake and the rpm performer air gap which flows pretty good right out of the box so let's take a look at the valve weight right here's our lightweight uh 516 stem valve and here's a regular valve right so well it's around 12 grams lighter so basically uh our afr valve at just on 100 grams is 10 to 12 lighter than its regular 343 or 11 30 second stem right it's probably not able to see the difference there but so what are afr's lightweight valves worth anything yes the reduction valve weight plus the fact that they come with light steel retainers on these heads means that the valve train replicates or say the valve train the valve mass replicates having titanium retainers instead of steel retainers a good steel setup is going to save you the cost of a set of titanium retainers for a regular sized stem valve having lightweight valves is a good approach to making a healthy valve train it's actually an advantage that this the cylinder head manufacturer could exploit by using a slightly less lesser quality of spring but afr did not choose that route as usual there as i said their hardware is very good and the choice of spring they've made has been a very considered one so i want to look at that spring in detail now so that you'll see that this hardware business is not just something i'm glibly talking about it's actually applied in principle so first thing let's take a look at the installed height of the sprains and work from there okay let's set the installed height first right let's put that to zero right got that now let's put our spring and retainer in and see what that is one 130 on the seat right now let's see what it is over the nose for a 600 lift at the valve the springs capable of 650 but let's leave a little on the a little margin here and check it at 600 that's the most likely maximum lift we'll use on a 302 or 331 or even a 347 for the street all right let's go around let's do that again one two three four five [Music] six hundred it is 350 pounds over the nose right i already have checked the spring rate and that is sitting right at 360 pounds so with its weight and its stiffness this is a very good spring well we've looked at the spring and at the valve right the only other thing i need mention here is that the studs are high quality the rocker studs are high quality and the uh guide plates are those adjustable ones not the fixed ones so it allows you to set your push rods up pretty much spot on no that's not length that's pitch this way right next move let's put this to the test on the flow bench and see where we get to um well there we go that's finalized our tests and we're looking good basically then it looks like the afr 165 renegade heads are living up to expectations and maybe a shade over that so that's good um i've just got all the testing done next step we'll go into the some of the details on what it does well the thick line here is our 165 cc port afr renegade head with the 1.9 inch valve this the thin line that is my e7 te head with a 20216 valve combination right and had trick valve seat and all this good stuff on there and a lot of porting and it made it was very strong on the dyno right you can see that right up until in this range here that the afr head shows itself very well considering it has a much smaller port and a much smaller valve so that our comparison is a little more fair instead of comparing them outright let's look at the flow efficiency because remember we're talking about a small valve head versus a big valve head well here we go the thick line is the afr intake valve efficiency and the thin line is my e7te head with the 202 valve you can see up here that we're hitting something like 87 efficient on on the afr head i can tell you now this is the highest valve flow efficiency at this lift of any of the aftermarket heads that i have tried right that includes at least half of them out there so one of the reasons why we can expect good performance on this is that this valve at low and medium lift looks a lot bigger what does a typical aftermarket head have this lift it's nearer about 72 percent so it's down here right my head's typically my iron heads that is typic typically are in the 80 percent range at this so and this is good better than anything you can buy except for this so major points for the cylinder head here very stout throughout now let's look at something that isn't very often talked about but if you're going to get serious about your cylinder head porting you have to get into the science of it this graph here is the port energy density in foot pounds per square inch per foot and it virtually dictates the success of a cylinder head in terms of its output we can look at these numbers here and we can say that anything which goes over about 20 foot pounds per square inch of valve per foot length support is going to make big horsepower well look at this we're up around the uh 21 and a half there and remember this cylinder head here produced some really stout figures and i'll give you an idea on our 10.5 to 1 motor it cranked out 1.395 foot pounds per cube check that out with other cylinder heads and you'll see that's a lot better than most of them do and that's a modified iron head what we've got here is afros not overly expensive 165 renegade head and it betters that so i'm expecting great things from this on the dyno exhaust was pretty strong right uh you can see that it's approaching the 200 cfm and hovers around 201 202 cfm for quite a bit up here so the thing is is we've got a good exhaust port as well but with a 1 6 valve there's no reason why it shouldn't be good and at least compare with other heads so let's look at it compared with my head with a 1 6 valve right my iron head now let's go to there now let's do it the other way around here we are thick line or renegade head thin line my e7te head now i have to tell you these e7te heads you can get a good port if you know what you're doing takes quite a bit of skill but it can be done so what we have here is an exhaust port which falls into the category of pretty damn good maybe could be a little bit better but really it's well balanced with whatever the intake is so airflow's renegade heads have good flow numbers good port velocity uh a very fat flow curve from efficient valves and one thing this doesn't show up on here they're very insensitive to octane rating in other words with a well-built engine they'll run 10.5 11 to 11 to 1 on 87 octane fuel now that doesn't come about easy the heads are capable you have to be a capable engine builder to extract that but let's let's look at this here's our flow figures right but they don't tell us exactly how much horsepower we're going to get now this is where we could get into something like a simple dino test to show but here's the problem with comparative dyno tests testing stock versus the modified one is that they may require different camshafts for optimum use so the iop program goes through countless i mean thousands of calculations to calculate what the potential horsepower is and it's very accurate let me show you here right so let's go to here quit quit go to this here and what i've done here is i've put in this is our opening screen i've put in the port area the flow at the lift we're going to use which would be about 580 lift i've put in the bore stroke the compression ratio the uh limiting mach number of the head i happen to know what that is but this program will calculate it for you pretty close right so hit the calculate button and and here what is what we've got it shows that this 331 model engine here has the potential to on 10.5 to 1 10.5 has the ability to crank out 460 foot pounds of torque and the port area port area limitations so this is when it reaches mach 0.56 is 560 horsepower the airflow limitation now this is a a number that's developed and it assumes that there is no restriction to the intake or exhaust the engine is perfectly cammed the friction levels are down at pro stock levels so this here is a number which you could get if you built something similar in sophistication to a pro stock motor so that that's just a guide there usually what happens is we get a number just a bit bigger than that if the engine's done right you'll notice that these there are these boxes down here best torque output this does assume you will install the appropriate cam for details on the torque master cam program click below that'll spec camera for you this one here this is the port area limited power set by the limiting port speed stated as the mach number that's up there so this is what we get close to in this instance this is the horsepower capability of an engine uh with a specific air consumption of 0.5 5.5 pounds per hour it's corrected for compression etc etc well i've gone into details on what that is now let's actually look and see what a real engine did this engine here was one that i did some years ago you'll see the afr well you may not be able to but if you've got a copy of my book when it comes out you'll see the afr logos on here it's a 331 10.5 to 1 motor right it had a uh super victor intake manifold single plane uh a holy a a holy uh hp carburetor i think that was about a 750. um the hei distributor on this was from from uh performance distributors right it's a gm distributor adapted to a ford works very well now then tested at terry walters engines what did we get for power we got 561 horsepower and 460. 61 foot-pounds of torque only one horsepower and one foot-pound different to the predicted now okay showing off here that is a bit closer than we normally see but this program is very accurate in what it determines the heads capable of so if you can build your engine right you will get very close to these predicted numbers a 10 horsepower uh error total is about it so you usually nine times out of ten plus a minus five horsepower and plus or minus five foot pounds right on a big block it might be a little bit bigger than that percentage-wise it's about the same anyway our next stage here is to dyno test these heads as i outlined before that will be in part two so thank you for listening thank you for watching thank you for putting up with all my stories and if you like what you see please subscribe and hit the like button thank you very much [Music] [Music] you

Channel: David Vizard Performance

Views: 16,138

Rating: 4.9670329 out of 5

Keywords: Cylinder head, Edelbrock, IOP, Induction optimization program, Porting, SBC, Vizard, chevy, performer rpm David vizard

Id: gZZA6bkEV1A

Length: 26min 29sec (1589 seconds)

Published: Wed May 05 2021