I am starting a thread to cover some of the "issues" with the AFR heads, so instead of having 25 threads on AFRs perhaps we can consolidate it into one thread, and some of the recurring questions can be answered up front.

[soapbox] I'm a little confused here. Most folks were excited about AFR developing heads (but some folks complain about the LT1 head). AFR keeps us posted about exactly where they are at, and exactly what they are doing (and folks complain). AFR does extensive testing to ensure that the heads are EXACTLY what they have stated, and what they have promised (and now folks are complaining about that). Does anyone see an issue here? AFR has been upfront about everything they were doing. The numbers the heads flow have been verified on 3 benches that I know of, and Tony's number was right on the money.

Tony has been upfront about what they intended these heads to be used for, and what the inteded application was. I'm not sure if folks can't or won't read his comments on these heads or not. It seesm like Tony has stated several times what these heads were designed to be used for, yet some folks don't use them that way, and then folks complain and start bashing AFR.

Folks keep clamoring for the aftermarket to bring parts to the market for us, and then when they do what do folks do? They crucify them based on bad data. Heres a little hint. Folks from the aftermarket do look at sites like LS1tech. If you don't want new aftermarket parts like heads made, then by all means just keep bandwaggoning on threads like this and making comments like "oh I never believed the hype", or "I knew these heads wouldn't work", or "I'm glad I bought (vendor x's heads).

So, lets look at the "issues".

pdd - Pdd swapped a set of Patriots and an LS6 intake for a set of 205's and an LSX. He picked up (as I recall) about 20HP. As I remember, everything else stayed the same, and the car is making great power. His issue was he felt like he spent a bunch of money for nothing, and in fact he did to some extent. But, lets look at that a bit more. You have a Patriot head with a 59CC combustion chamber, and you swap it for a head with a 66CC combustion chamber and drop a FULL point of compression. Does anyone see an issue with this? Here is a simple question for folks. If I take the LS6 heads off my Z06 and replace them with a 6.0L head do you think I might loose some HP??? I mean c'mon ports are about the same, I'm only droppping compression right? Does compression matter? You bet it does. I think Tony has time and time again tried to point out in a max effort combo DO NOT USE THE 205's, wait on the 225's.

In pdd's defense, he didn't mill the heads, since he didn't want to flycut his pistons. I understand that. But, if thats an issue, I'd look at using a cam with a bit less lift , or go the flycutting route. If not, you will have to live with that drop in compression, and the loss of power associated with it. I think many motors could be built with a lot less lift than they are runing, not have to flycut, and not have PTV issues (but thats just me). But in AFR's defense, I don't think its fair to bash someones product based on an unfair comparison and leaving power on the table.

Now, folks are saying its not making 480HP. Well, lets look at that. HP to some extent is based on cylinder head flow. We used to take cfm and multiply by 2.15 to get max HP (ghetto math) in a race motor. Anyhow, once you find your multiplier it seems to hold pretty true. I guess what I am saying is that if you have two GOOD heads that flow eactly the same, don't expect 50HP on a head swap. Which I think is where we are at with pdd's car. I think that the motor will rev quicker, I think it will be crisper, etc... with a smaller port. But at WOT, they are both flowing about the same, so I don't expect super huge gains. If I did, we'd have already put a set on the H/C Z06. But, I will say that if you keep the combustion chambers the same size(thus keeping compression the same) and put the AFR in a true head to head comparison they will make more power than a ported stock casting. Of course this also leads back into the cam thread about selecting the right cam for the job (but I digress)...

Now, lets look at McRat's car
I saw his car run, and it did make good power. But the car obviously had isses still. On that day in BG I was a second off and 5MPH slow int he 4 cars I drove over a decent day in Houston. Lets also look at where some power is being lost in McRats car vs Tony's car (since they are both C5s). First off, Tony is running 3.42 and McRat is running 4.10s (so there is 7-10HP) right there. So lets say a gear change back to 3.42s takes the car to 455 (+7HP). Now, lets look at the exhaust. McRat is running the stock Ti catback. Its a good system, don't get me wrong, but its not a max effort system either. On a stock car headers and exaust are worth 20HP. The Stock TI mufflers alone are worth 7-10HP over and open pipe. On a modified car I would suspect you might loose as much as 10-15HP over one of the "race systems" like the PRTs we run (they are loud, but they flow). And as it so happens, Tony's car has aftermarket exahust on his car. So, lets add another 10-15HP (we're now at 465 (+10)). Now, we look at the headers 1 7/8" headers ona stock 346. They might be alright for a 408, but the yare too much on a stock motor, and McRat agreed with this when I talked with him about it. Tony's car made 460-470 with Kooks 1 3/4, and when he switched to the LGM headers he went to ~480RWHP. So isuspect that if Mc Rat switches to a smaller tube header he will find even some more power. Lets say another 10HP (So now we are at 475, and all this is based on conservative estimates its more like 483 if you go on the more optimistic side). Hey and you know what, that falls right in line with what Tony saw (isn't that incredible)...

Now, we go to the last thread which has popped up recently from Mike Norris. I'm sure Mike is a nice guy. I've never met him, but the thing that strikes me as odd is how blind some people seem to be. Don't the before dyno numbers seem to perhaps be just a smidge on the low side? Has anyone seen a car dyno that low before either stock, or with bolt-ons? Mike has even stated there may be an issue with his dyno reading 5% low. Does anyone see a 5% variation as being a cause for any concern? Add 5% to those dyno numbers, and the car is at 420-430HP. Obviously there is no way it could be the dyno, it must be the heads... One of the most ridiculous comments I saw was made to the effect of "if the car had been tuned before, the gains would have been even less". Let me ask a question do you know of any shop who optimizes your combo on the dyno before they work on your car. Oh heck yeah, I'm sure Jayson @ MTI, or Lou @ LGM goes out and tunes your car to the Nth degree and get you the best dyno sheet you've ever seen on your car right before he does a H/C on the car so you can be disappointed in the gain. C'mon people use your brains... I don't know how many times it has been said, or how many times it will need to be repeated dynos and flowbenches vary. Sometimes by a lot. SO, you have to use them as a tuning tool, not an absolute determining factor in the worth of a product. An 80HP delta over stock is pretty awsome as far as I am concerned. When we went from a stock Z06 with headers and bolt ons, etc... to an LGM G5X3 we saw an 85HP delta (393 to 478) and folks were estatic. So, this guy saw the same delta in a stock car that we saw with one of the most max effort package out there. The motor also now revs to 6500 wher ewhen it was stock it started dropping after 6200. So if you looka the delta at 6500 it would more likely be close to a 100HP delta since the stock cam falls on its face. But I don't think most shops do that either.

 

What I am trying to say is that if folks want Tony's numbers you need to duplicate that combo. As you can see Tony saw 10HP just in a different header with a longer primary. What I am trying to say here is that every car that has been tested and has not been where folks thing they should be at has a verifiable issue that still remains unresolved. I haven't seen too many mentions of the cars they made as much or more power as expected once the AFR heads went on. For instance LGM has done some packages with the AFR heads and had VERY good results with them. The problem is you have couple of guys who have some issues to resolve, and all of the suddent AFRs are a big pile.

Until some of these issues are resolved one way or the other I think it is wrong for folks to pull out the toches and burn Tony and AFR at the stake.

I'll say it again, if you guys want parts developed for our cars, you need to think about what you are doing when you start bashing guys for giving you what you want. And then complaining when your combo, or your dyno, or whatever is wrong. All of the sudden it their fault.

One other thing, you don't need to justify your purchasing decison for buy (vendor X) heads. I saw this all during the TEA vs Patriot stuff and it just makes me want to . Grow up people. You bought them, be happy with them. If I buy GTP or AFR, thats what I want. You bought what you want. Its all ok. Folks seem to find it necesary to jump into t thread and then bash on whomever only to post how happy they are they bought (vendor x's heads). Its just so obvious sometimes that folks are trying to justify their decison to themselves. Ther eis no reason for this, and folks just need to show a bit of maturity.

Its whole lot easier to just write you and your extinct F-Body off then to waste time and resources developing something for a bunch of cry-babies.

If you want to be constructive and help out, then by all means do so. If you want ot whine and complain and just generally slow down progress then by all means plase feel free to move to a site like LS1.com. This site is about technical content, and technical development of the LS series motor. Not high school drama.
[/soapbox]

Now, feel free to discuss any issues you might have with the AFR heads below, perhaps before they turn into a dog pile we can get things sorted out and make folks happy.

 

Well written. I'll be following this thread for more info and I hope it stays civil.

 

Well, I agree with what you said.
I'm getting AFR's 62cc with a Stealth II 224/220,.581/.581 116+0 lsa and hoping to be close to 420>430 A4 through 10 bolt. I'll keep you posted how it goes.
1st I'll dyno my car as is for base.
The only addition beside H/C swap will be a March 25% UP so it will be a close before after comparison.

 

I completely agree, and will be right here along with WS-Sick, as I'm contemplating these heads for my ride.

 

We got nice numbers out of our AFR porter versions.

We should have dyno numbers in the next 2 weeks. ITs a stock bottom end with AFR heads custom grind cam and a FAST 90mm intake. Its going in our shop Vette with a Z06 tranny and 4:10 gears..

500 RWHP?? Time will tell..

 

Right on J-Rod! Saved me the time posting because I was having the same thougths. Tony has been very open and hoest with everthing that he has done, even dynoed his car in public and we still have doubting Thomas's.

Every motor is a bit different and certainly most people have different header and exhaust combo's and don't realize how crucial all of the matched components are.

And when it comes to "bang for the buck", I have yet to see anyone's heads compare to the 205's thus far.

 

J-rod, great post. However, I do think it's important, that IF we're going to compare before and after numbers, that the before numbers be good numbers. Numbers made with a 10.5:1 fuel/air ratio aren't so great to compare with after numbers at 13:1. In that case you can't say "I picked up 86 RWHP from the cam, heads, and UD pulley." That statement wouldn't be true. For instance, my before heads/cam numbers were 351 RWHP. This was with a fuel air of 13.3:1 and timing of 28-29 degrees (yes, MTI did a tuned "before" on my car at my request.) Afterwards the numbers were 423 RWHP. Again, the fuel air was 13.3:1 and 28-29 degrees. Thus, I can honestly say that I got 72 RWHP. But on the otherhand I could have brought my car into the shop running dog rich and with low timing advance and maybe the car would have dynoed 323 RWHP beforehand. Sounds fairly ok for a bolt-on car, ehh? Who would have thought that it wasn't tuned properly? But then I would have seen 100 RWHP from the heads/cam install!

Anyway, just pointing out that I think when comparing before and afters we have to consider ALL aspects.

 

Hey J-Rod,

I am a nice guy I knew when I started that thread it had the potential to go bad, so I "babysat" it as much as possible. I initially did not want to say what the final numbers were cause I know a lot of folks see just those numbers and then are suddenly blind to anything else written.

I thought the gain of 84RWHP was very good for just adding heads/cam and UD pulley and was just trying to see if this was the norm for these or are we missing more. After talking with AFR and another independent shop, 85RWHP gain is in the ballpark for sure and now we figure out why this car itself is low. I am sure it will be fine in the end. I don't mind folks being critical as long as it is civilized. I asked for pretty much specific info and explained things out a few times, but there were still folks dwelling on the final numbers instead of a valid comparison of delta gains from one car to another.

The reason I posted here also was to get an indepent shops results over AFR's so it would not be biased. I called the normal shops I deal with and no one had done the AFR's yet. I could have called AFR initially, but when calling the vendor for some product feedback, any vendor for that matter, and though I like Tony and the rest of the folks at AFR for sure, I would expect a somewhat biased response. I could be wrong and not judging anyone. I think they do great with their info and in this case the delta gains claimed were there. I would not expect someone to call AFR for a reference and they say "Call Mike at Next Level Performance. Though they only made 395RWHP, it still picked up 84RWHP with our heads/cam upgrade". People, no matter what the gains are, focus more on the final numbers. Is it right? Not exactly, but human nature. Most folks would rather be critical then give praise.

Thanks for the post J-Rod.

Mike Norris

 

Mike, I don't want you, McRat, or pdd to think I was flaming any of you. I've met McRat and IMHO he and his wife Kat are a riot. I enjoyed spending time with them @ the Z06 fest.

I can understand PDD's issues, as he spent a ton of coin, and he didn't see the big jump he expected. I can certainly understand that, but I don't know that any of these issues are AFR issues, or should be more focused on the end user and variable beyond the control of AFR.

I think Tony really cares about this product, and want everyone to be satisfied with their heads. I think he is trying to make sure everything that ships is 100%. Every time someone has asked something of him he responds, and does so quickly. I don't know that I could ask more from any vendor.

Mike, in your case. I have seen you on the boards since I first came onto the LS scene, and I can't remember ever seeing any "drama" out of your shop, etc...

So, hence my comments. You are along way from me, but everything I have seen from you or on you indicates you are a pretty stand up guy. Hence my comment that I'm sure you are a nice guy. You didn't come in called Tony names, or hurling accusations. That was done by other folks a bit later. I think you asked a fairly reasonable question, unfortunately folks took the opportunity to conver the thread into a free-for-all.

Anyhow, my hope is that your customer can get the performance, and not necessarily the "number" he is looking for. I'd like to see him get his number too, as some folks really want to see that sort of thing (and I understand and appreciate that). Numbers are nice for bragging rights (which is cool and all), but the performance is whats going to get you the win. Anyhow, I'm hoping the "missing" HP can be found somewhere, and everyone can get back to whatever it was they were doing before.

So anyway, anyone else have "issues" that need to be addressed.

 

Anyhow, my hope is that your customer can get the performance, and not necessarily the "number" he is looking for.

Yeap, I know what you mean. I'm much more interested in achieving 11.2's N/A than dynoing at 450rwhp and running 11.5's. I know that Stealth II can do that with the proper heads (Colonel), so that is really my goal, but with AFR's.

 

QUOTE,
One of the most ridiculous comments I saw was made to the effect of "if the car had been tuned before, the gains would have been even less".


Colonel, the above quote was attributable to me. I appreciate you setting Jrod straight and explaining that one has to compare apples to apples. Thanks again!

 

[QUOTE=J-Rod]

pdd - Pdd swapped a set of Patriots and an LS6 intake for a set of 205's and an LSX. He picked up (as I recall) about 20HP. As I remember, everything else stayed the same, and the car is making great power. QUOTE]

you are incorrect. i added a 90 fast intake and 90 TB and a 85MM MAF sensor with the heads. so i picked up 20 from the intake swap NOT the heads.if i milled them i would of maybe picked up 20hp so id be at 455, with a bigger cam. its a far cry from 480, but i guess no one independent ever gets the good results of the vendors. my future might bring good things with these heads unmilled ok im done with rattling about the heads.there a nice piece of work. now i want to work with the heads to make more power and find out why i have this crazy hump in my midrange

 

Again that was my point you didn't gain anything with a head swap you gained on the intake swap. I.E. lower CR heads with the same flow made the same power as your other heads. I think CR will help , and thus you would have a gain over your other heads.

You have 3.90's as opposed to 3.42s which are worth a few HP.

Now as for cam, There could be some optimizing that could be done there...

As for the hump in the midrange, is it a hump, or is your graph falling off for some reason. Since there are LG Headers on the car, is there a dip around 2500 in the graph also?

 

ppd,
have you thought of the header 17/8 and 13/4?
What 85mm Maf are you using?? SLP? if so dump it and put the stock one back on. Too big of a header will create too much suction capable of sucking part of the intake charge depending on your overlap. That also can attribute in a loss of power.
Call me crazy but a stepped 15/8>13/4 header might help bring more low torq from your cam, still allowing it to breathe at top end due to the increased velocity at which AFR flow.
Just some thoughts.

 

pdd's sig shows LGM headers which are only avaliable in 1 3/4".

Just to expand on things a bit. A point of compression should be worth about 4% HP wise, perhaps a bit more (but I think 4% is a safe number). So, if you look at pdd's car, he saw a 20HP gain by swapping an LSX intake with a 90MM TB from an LS6 with a BBK 85MM TB, along with the AFR heads. Along with taking a 4% power loss from dropping compression.

So, you have 20HP gain. Factor in around a 20HP gain from upping the compression to match that of the Patriot heads. Thats about 40HP overall. If you subtract the gain from the LSX/90MM (about 10-15HP) that still leaves you 25-30HP gain over the ported stockers.

Again, pdd didn't see a gain, but I think there was power left on the table. Yes, he saw a gain you would normally associate with one one of the items, and not what you would expect with both, but I think if there were an apples to apples comparison I feel the numbers would be a bit higher.

pdd I think you have a good solid combo, and you have the makings of a very fast car.

 

J-rod,
A good rule of thumb on the compression; for every point gained over 10, it is worth around 7% of the CID. IE 346 x 7 = 26HP. We tried this with a 283 years ago.

Chris

 

Great post J-Rod, couldn't have said it better myself.

Their ya go, good as advertised.

 

[QUOTE=PREDATOR-Z]ppd,

What 85mm Maf are you using?? SLP? if so dump it and put the stock one back on. [quote]

its a z06 85mm MAF
heres another photo of the my dyno sheet. the mystry hump remains
http://www.picturejudge.com/memberpi...s/IM000378.JPG

 

I'm happy AFR has stepped up and are producing heads for our cars. I hope Edelbrock and others will follow. I'm sure the AFR's will be the way to go, once the talented porters get some time with them. The problem is, Tony said before they were released, that they would be up 40 hp over ported LS1 heads. As we have seen, that has NOT been the case. So what you have is a great head, with thick decks, that is about on par with a set of ported LS1 heads. Not bad, but not exactly what was promised.

Bruce