thanks for the replies guys. will see what it does at the track. im goin for the first time in oct

 

well as said before watching the AFR car dyno at the LG motorsports dyno day.. its air/fuel was 14.1-14.4 .. pretty damn lean if u ask me but somehow its still running strong so maybe they can include this special tune via mail order or somethin

 

I tried many tunes in his car.Even 14-1 A/F and nothing brought the power up so we did the safe 12.8-1 across the board.I'm actually impressed with the gain.
As said above that the shop cars dyno highest,that is true.I've done a few of the T-rex installs with all the bolt-ons.After hours on the dyno I never saw one push more than 405rwhp.Maybe it is my dyno?If it is I better check my car,should be 600rwhp

 

Werd I agree the lobes make the big difference not the duration and lift numbers.


I agree the more compression the better. BTW that is a very nice all motor setup you have. I'm trying to do an 90 MM FAST Hand Ported AFR's w/ welded chambers and a custom camshaft w/ similar compression.

How did you arrive at 12 1/4 compression though? Milling or Pistons? Also what intake are you running?

Thanks

Floyd

 

im at 12.06 CR with 64cc chambers, 6.6 effective domes, .043 gasket, and pistons out the hole -.008

 

Thats very nice too. What head casting did you select?

 

Hate to ***** but both of you, and the original poster have some very nice setups. The ideas I'm getting for the new motor lol

 

well you did make gains in hp and tq so that is a plus but you had a pretty good set up to begin with

id wait and see what others are getting for results with the new AFRs before you condem them

 

I believe the CR defentially hurt the performance.
You had a good TB on the car already and a LS6 intake.
Just a guess but if all things were equal in compression I believe a ~30 HP difference would have happened. That isn't bad considering you already had good heads.
I will also say through a cutout on the car and get rid of the cats and you should see a healthy difference.

 

Chef, when is eastside gonna start playing with these heads? I'm looking into the head cam swap next summer, think you'll have them tested by then?

 

yup were are looking into them right now actually, by the time you are ready im sure we will know what will be best for your needs

 

heads are 853 castings ported of course. DCR is 9.1 ,motors a forged 347.

 

I'd have to agree with Chris on this one.
Once your at 400 to 420RW I wouldnt touch the car,I was gonna pull my cam but talking to a few people on here I've decided to just add the LSX/90 when I get some extra money.

Done correctly its worth 12 to 15RW on a setup like mine and that would put me over 420 threw a loose verter/12-bolt.I'll be VERY happy with those # running a ported LS6 head and a 224-224 580-580 cam.If that were my vette I wouldve left the PP heads on the car and just added the intake/tb,u wouldve been right where u are now or very close.

JMHO.....

 

As things come with time, we will know more about AFR LS1 heads. I think there is still a lot to learn about these heads. I think this is a GREAT starting point and should be used to make forward progress. Go get some 11's at the track and you'll be

 

Those gains under the curve all over are nice compared to the PP ls6 s2's, I bet it runs a real good ET on those.

 

Make sure you look closely at the scale of the torque. Each increment is only 5ft lbs. It looks like a lot because of the way the graph is scaled, but it's really only 5-10 ft-lbs, except towards the peak where it's closer to 15 ft-lbs.

I'd like to see what this setup dyno's with the LS6 intake/stock TB back on it.

 

looks like it's down over 1 full point of compression and their still making more power?
man, tuff crowd! best guess is 5-7% for each point. that has to be at least 15-20HP
across the board...

 

I think the question to ask is why even bother going to AFR heads when you already had PPS2 heads? It's not like he only gained 20 rwhp over a stock set of heads. He already had pretty good heads. Rather than spend all that money I personally would have just purchased the FAST 90 Intake and TB. Probably would have had similar gains.

 

Guys...

Some things to consider.

A 66 cc chamber is worth 1 full point of compression loss. I'm confused why someone searching for additional power and spending thousands on a headswap would have let that go, but everyone has their own agenda.

Every point of compression is worth a 4% increase or decrease in power. I did not pull that figure out of my butt....It is a generally accepted fact and proven recently by dyno testing the same motor at Westech's testing facility here in CA. Hot Rod covered the story. Compression is cylinder pressure and cylinder pressure is power.

The 4% loss should be calculated at the flywheel, but even if you take 4% of 434, that would account for a 17 HP drop in power (20 in reality assuming 434 is worth 500 HP at the crank).

The Fast 90 comparison was also not going against a stock manifold / TB set-up. As someone here also pointed out, the engine already had an 85 mm TB.

Assuming the Fast 90 set-up was worth an additional 10-15 over the 85 mm LS6 set-up (15 probably generous), it looks to me the AFR heads made somewhere around 20+ HP more than a fully ported head to begin with (correcting the #'s for similar compression ratio's).

Not to mention the power and torque even with lower compression was up significantly EVERYWHERE, showing the benefit of the high velocity/high flow 205 port design. Personally, I think the results were VERY favorable. What kind of results would you expect to see over an already fully ported set of cylinder heads?

Regarding my personal car you have read about...

Yes, it has full exhaust with metal matrix Cats

I spent the time to port match and better shape the exit of the FAST intake...worth 6-7 CFM to the cylinder head and at least that much in power gains.

My car was almost a full point higher in compression ratio.

I run a tighter "quench" with an .040 Cometic gasket.

I run both the electric water pump and underdrive pulleys (probably 8-10 HP or so total)

I currently run a header with extremely long primary pipes and a merge collector which I feel is an ideal set-up for my particular combination and helped my generate more power and torque.

It's all in the details guys....my engine has a leakdown of 2% or less on every hole....I spent 4 hours making sure my camshaft was installed EXACTLY where I found it to make the most power on the engine dyno. (2 degrees in the wrong direction and say good bye to 5-7 HP).

And last but not least....hit that thing another 50 times or so on the dyno....I bet another 10 HP is just hiding waiting to be found. Maybe, maybe not, but you get my point.


In my opinion, too many variables were changed for it to be a relevant A/B test, but if you look over all the facts closely, it seems to me the benefits of the AFR head design are still readily apparent.

Just my .02

Regards to all,
Tony Mamo
AFR Sales / Product Design

 

I agree with Tony.The heads do work Of course I would rather have them slod with a smaller chamber like 59cc which is what most of the customers want.That way we can run big Cams,high compression and not flycut the pistons

Now,is it worth getting these over ported heads you already have?Probly not if you don't have money to burn.But if you don't have heads already then these are the one's to get Or you can wait and see what the porters can do.The problem with heavy porting is that your killing the small runners that the AFR's stand for