Best HCI combo NA?

FastDriver · May 11, 2011

I still think some of you guys are not giving the AFR165s and AFR185s enough credit. There are so many guys making 300-320 rwhp with the 165s and awesome torque from the little motors. Off the top of my head, I want to say those heads for 230cfm.... that's enough for around 500hp tapped out. 300rwhp is about the worst I expect to see from an AFR combo w/ a 5 speed. The best fuel injected combinations are pushing 340-350rwhp on a 302 with those heads.

The 185s are, IMO, the perfect sized head for a 331 with a stock block... You will not run out of air within the rev-range of a stock motor at that displacement. I've got 205s on mine, but I'll bet I'd see a little more power with some competition 185s. I'm not upset about that, as I intend to rev to 8k+ RPM some day. Nevertheless, I think you'd be hard pressed with any other head to pull more than a handful of hp more out of a 331 at or below 7k RPM than with AFR comp 185s.

Chris

FastDriver · May 11, 2011

Nik,

Articles like these have me starting to lean your way in the port velocity vs. bigger is better argument.

AFR 165 cc vs. AFR 185 cc
AFR 165 cc vs AFR 185 cc Aluminum Cylinder Heads

2000xp8 · May 11, 2011

While i think 185's are fine for 331, it doesn't go with the "build for the future" plan.
The whole idea of building a better engine with parts from a previous engine is a catch 22.

So instead of getting 165's for the 302, you stretch it to 185's, but now the 185's aren't perfect for the 331 so people want you to get 205's.

IMO, just get the easily bolt on 165's, run them, and if you get the 331 done (a good percentage of people talk about it, and never get it done) either sell them and upgrade or have them cnc ported.

Bottom line, the perfect engine will never be built with the parts from your older lower displacement engine.

My idea of building for the future would start with building that 331 out of a boss or dart block, i wouldn't be stressing over the heads, since they are fairly easy to change.

NIKwoaC · May 11, 2011

FastDriver said:
I want to say those heads for 230cfm.... that's enough for around 500hp tapped out.

Honestly, Chris, I hate that "CFM x 2.X = HP capability" rule of thumb. I see it over and over in tons of different places, but this is the thing: when have you ever seen AFR 165 anything make 500hp NA?

In some cases, you see bigger, more race oriented heads live up to that rule of thumb, but then you're talking about a 300+ CFM head with some huge solid roller and lots of compression.

FastDriver said:
Nik,

Articles like these have me starting to lean your way in the port velocity vs. bigger is better argument.

AFR 165 cc vs. AFR 185 cc
AFR 165 cc vs AFR 185 cc Aluminum Cylinder Heads

I'm telling ya man, I have yet to see anything that actually proves "small" heads are better than "big" heads at anything. I mean, that's simplifying it a lot, but in an all-else-equal situation... Is there really any benefit to using a smaller head, from a performance standpoint? Is there any evidence to support it? :

Rick 91GT · May 11, 2011

I have a customer a 8.5:1 331, mildly ported 185s, ported spyder intake, custom cam, 80mm turbo...makes over 1100hp at 18psi.

10.7:1 333ci, out of the box 185s, stock untouched Cobra intake, custom cam, 70mm tb, 75mm maf, 30lb inj, shorty headers...on a stingy mustangdyno made 380/404 to the wheels. Power done at 5800.

I find guys go to big on the head in many cases without enough motor.

The 185 is a bad ass emissions legal head.

Rick 91GT · May 11, 2011

Heres another, stock 93 Cobra, added AFR165, 1.7 stud rockers, shorty headers exh...304/338 to the wheels on a dynojet...

FastDriver · May 12, 2011

What RPM on the first turbo combo? And that's not rwhp is it? If so, that's a friggin' monster, and I'd be a little jealous, unless he's turning the motor to 8000rpm+

on the second combo, I made similar power numbers, but not similar torque with 8.5:1 compression breathing through the turbo kit, and an AFR of about 14:1 with a base tune and no timing adjustments... I probably would have picked up some decent rwhp and low end torque, but perhaps not that much. Definitely a fine showing of what AFR185s can do on a 331, bro.

Nik, the 2.2 rule is pretty accurate, but it takes a monster cam and the correct induction. The reason you don't see it is because the only way to get those numbers is to spin the motor higher than you would with a stock block, and nobody's building a Dart 302 or stroking a motor and putting AFR165s on it. The combo doesn't make sense. But if you're keeping your powerband below 6k, then the heads still do make plenty of sense. Even if the port velocity argument is completely bunk, which I haven't given up on yet, the AFRs outperform most of the heads out on the market for the 302, are cheaper than the 185s, and as mentioned already can just be bolted on.

Additionally, the combos in the articles I linked aren't quite built right to take advantage of low end torque. One has an RPMII intake which is known to produce less low-end than GT40 style, and holley systemax style intakes. The other has a 23x/240 duration cam, which again strays from purpose. What I'd really like to see, in order to put this case to closure, is a comparison where the motor is built for AFR165s, and then 185s are swapped in their place. A street motor with less than 230@.050" with a ported GT40/systemax/ported Edelbrock 5.0 intake and some decent compression. I somehow now suspect the 185s would either outperform the 165s or the difference down low would so slightly favor the 165s that I still wouldn't prefer them.

Rick 91GT · May 12, 2011

More like 7000rpm...

Here's a vid of some of the first pulls with a single disc clutch that wasn't holding, 973RWHP/934RWTQ

360ci (3.4 stroke, large bore), 15:1 comp, Brodix T1 fully ported, Fully Ported Super Victor, 1050 Dominator, 780HP+ (hard to get a good reading with the converter on the dyno) 8.6 @ 153mph, 3150lbs. This is a good example of a big head, 350cfm+ on a small motor works...but it has all the other goodies and compression behind it.

FastDriver · May 12, 2011

Not bad, Rick.

NIKwoaC · May 12, 2011

Rick 91GT said:
10.7:1 333ci, out of the box 185s, stock untouched Cobra intake, custom cam, 70mm tb, 75mm maf, 30lb inj, shorty headers...on a stingy mustangdyno made 380/404 to the wheels. Power done at 5800.

I'm not so much doubting the heads on this motor, but an untouched Cobra intake that made 380 to the tire N/A? Has this been verified on any other dyno?

If that is a legit 380 to the tire, that car is a freak! And also probably an exception to the rule. What were the cam specs?

FastDriver said:
Nik, the 2.2 rule is pretty accurate, but it takes a monster cam and the correct induction. The reason you don't see it is because the only way to get those numbers is to spin the motor higher than you would with a stock block, and nobody's building a Dart 302 or stroking a motor and putting AFR165s on it. The combo doesn't make sense.

Haha, you'd think that would be true, but every once in a while, you see somebody build a 347 with 165s because "it's just a street car" and they "want good lower end torque"... And then it makes 302 power on the dyno and is done breathing by 5000 RPM. If the exact same engine would have had 185s or even 205s, and was cammed properly, would it have actually given up anything down low?

FastDriver said:
But if you're keeping your powerband below 6k, then the heads still do make plenty of sense. Even if the port velocity argument is completely bunk, which I haven't given up on yet

And you shouldn't! I think there is valid argument for velocity, I just think too many people worry about it when it isn't even very well defined. What is velocity? How much is too much, and how little is not enough? Can you affect it with cam timing, or is it fixed by virtue of cylinder head choice? These are the kind of questions that don't really get answered, people just wave their hands at the "big" heads and say "no velocity, no low end torque". Then they build a SBF with the same small heads that have been used a million times before, and they get predictable, mediocre results.

FastDriver said:
Additionally, the combos in the articles I linked aren't quite built right to take advantage of low end torque. One has an RPMII intake which is known to produce less low-end than GT40 style, and holley systemax style intakes. The other has a 23x/240 duration cam, which again strays from purpose. What I'd really like to see, in order to put this case to closure, is a comparison where the motor is built for AFR165s, and then 185s are swapped in their place. A street motor with less than 230@.050" with a ported GT40/systemax/ported Edelbrock 5.0 intake and some decent compression. I somehow now suspect the 185s would either outperform the 165s or the difference down low would so slightly favor the 165s that I still wouldn't prefer them.

See, and the underlying message there is that it's all about the combo. Any one part isn't going to make or break an engine, it's all about the setup as a whole.

And on that note, I'm inclined to believe, that for a given engine size and a given RPM range, a big head/small cam engine would be a better all-around performer than a small head/big cam engine. But you've heard me say that before.

90lxcoupe · May 12, 2011

If you would just finish your car then mabye we could clear a little bit of the confusion up!

NIKwoaC · May 12, 2011

90lxcoupe said:
If you would just finish your car then mabye we could clear a little bit of the confusion up!

Haha, I know, dammit. I got the new fuel pump in and the tank back in the car this morning. Just need to button up the exhaust then the car should be able to come down off the jack stands finally.

90lxcoupe · May 12, 2011

im not one to talk, my cam swap has taken me almost 2 months now... Speaking of, i just answered a question you had a while back in there

Rick 91GT · May 12, 2011

Johns a member on here, the car is awesome. I did a custom cam based off some of Comps Nitrous lobes its I.555/.575 228/236 112 or 114 off the top of my head. That was after a cool down period with great cool, good air. On back to back hot pulls in the summer day earlier it was high 360s/380's. Ots got a tq curve like a big inch motor and pulls on his buddies 03 cobra. It made more...and this dyno is known to be stingy and well calibrated.

rustyruststang5 · May 12, 2011

2000xp8 said:
I don't think you can use 185's with a stock shortblock.
More like 165's.

you are correct i learn this the hard way. pistons will smack valves for sure. and 185s are to big of a head for a non stroke motor. i say this from exp. 165 will be a better choice head.

rustyruststang5 · May 12, 2011

my set up right now is afr 185, dss racing pistons in a 306, unknown cam (was told trick flow stage 2), trick flow intake 70mm tb, 30 lb injectors, 75mm mass air. with a 3000 stalled aod. no dyno numbers but i think 165s would be better for my motor because i do not have a supercharger, turbo or stroked motor. but im am glad i got the 185s because i am getting ready to get a turbo when i get back from afghanistan.

NIKwoaC · May 12, 2011

rustyruststang5 said:
you are correct i learn this the hard way. pistons will smack valves for sure. and 185s are to big of a head for a non stroke motor. i say this from exp. 165 will be a better choice head.

You've got an engine with an unknown cam and no dyno numbers, and you can say that the 165 is a better choice than the 185 "from exp"? What experience, exactly?

Rick 91GT · May 13, 2011

There is some good info and discussions in this thread and some bad...we all are going to have different opinions and that is great, there are many ways to accomplish the same goals. I just want to dispute a few pieces of bad info. Im not a keyboard jockey, I am a professional and provide real numbers, real data or expierence I personally have.

FIRST AFR 185's (like other 2.02" intake valve heads) will fit on a stock shortblock with notching. While notching can be an expensive option, I have a custom fixture and tooling I made to cut these while the pistons are in the block, if I build a motor I charge $140 to do it (that is where Steve got the pricing)

NikwoaC touched on it, it is 110% dependent on the "ENTIRE COMBO" not just the head. The 333ci example I posted above surprised me, I never thought I could make that much power through a Cobra intake and wanted John to put a Holley or RPM II on and let it eat. I know the TQ curve would be different put the HP would surely increase and I would expect peak numbers to be atleast 500-700rpm higher. MM&FF was escatatic in this months edition with the power they made with their 347 project, I've made more power with less and out of the box heads....example Johns 333ci.

Steve "the original poster" asked me about a H/C/I swap on his 93 Cobra after we get his exhaust and some other small issues up to par. He wanted some advice and I was trying to steer him in the correct direction, he is a little raw to this performance stuff. I threw some combos out based on what we discussed as his future plans, the AFR185 will more then feed what he needs and stay emissions legal. I also looked at the TFS combo with a Track Heat Intake and my own custom cam, the TFS TW head is very efficent, always has been. His plan include a 70-76mm turbo and 8psi down the road on top of a DART based 331 (which he plans on) will make more then enough power for what he wants. Id actually like to put the AFR185's, my own custom cam and the Cobra intake back on the car and keep the Cobra look under the hood. The Cobra has enough cross section to support over 350HP with easy, it's the lower that is a major restriction, porting can solve that. If we weld the lower up and fix the few problem runners it can be even better. If the intake wanted to be kept Extrude Hone does wonders to them, the flow numbers are very impressive.

I also prefer to have a large head and smaller intake then vise versa. Look at the NMRA Pure Street cars, the TFS TW head ruled that class, 310ci, ported TFS heads (around 185cc), 10.5:1 compression, ported Holley's, crazy hyd roller cams with .500" lift and 260+ duration @ .050" and lots of good ole rpm, 7500+ (some current guys turn 8500-8800rpm, factory hyd roller lifters) make 430HP+, and go mid 10's @ 125+mph all day long at 3150lbs. Is it streetable, yeah but not a daily combo for 98% of us.

HP is for bragging rights, TQ makes you fast...the more under the curve the better, peak numbers don't mean ****.
whew....said my peace

FastDriver · May 13, 2011

Nik,

I think he's referring to his experience with PTV contact on 185s...

Easy there, stud.

Chris

89stang1 · May 13, 2011

rick your memory is good i have longtubes tho not shorty headers heres the dyno readout

Best HCI combo NA?

FastDriver

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