Guys...

I thought we all needed a "diversion" here.

Let me share with you some facts I have previously mentioned but might have gone un-noticed or simply forgotten in the past.

We have already done an A-B test with a pair of stock LS1 heads versus our "out of the box" CNC ported 205's (un-milled) on an engine dyno during the development of our 205 program. In fact, our current "production" pieces are actually a few cc's smaller and flow a few CFM more, but the results if done today would certainly be similar if not better.

We had a bonestock LS1 engine on a SuperFlow 901 Engine dyno (not a chassis dyno) with the only "mods" being long tube headers. The motor had a stock LS1 manifold and throttle body. I don't remember the exact numbers (I believe the "stock" configuration actually put down 420's...don't forget the motor had ZERO accessories and had the benifit of long tube headers and 3" Flowmasters). We baselined and "tuned" the stock configuration so we weren't evaluating anything except the AFR heads....a TRUE A/B heads comparison. With the same exact head gasket and un-milled AFR 205's we saw a "peak to peak" gain of exactly 37 HP after we also "tuned" and optimized the A/F ratio. Better than even that was the fact that the stock headed motor was "all done" by 6000 RPM's and by 6500, the AFR 205 power advantage climbed to 58 HP!! (Don't forget that this is a BONESTOCK engine with just a headswap and no bump in compression ratio). Also, the AFR headed combination was up immediatly in torque and power output from the moment the engine started its climb (2500 RPM's)....the gap in power just kept getting wider as engine speed increased and the demand for more air become more important. Even with the "baby" stock LS1 cam, by 6500 RPM's the AFR headed engine was only down 7 HP off of its much higher peak, while the stock headed motor had given up nearly 30 HP (from a lower starting point). It's clear that the more efficient, higher flowing cylinder head was still getting the job done with no other "complimenting components" coming to it's aid (better intake, cam, TB etc.).

The other information I would like to share with you is much more recent. This information revolves around our recent "emissions" testing performed independantly (obviously) at the C.A.R.B. (California Air Research Board). We had to use a bonestock Z06 (due to it being "dirtier" than a lower output LS1 engine) to get the state to ultimately approve our heads and give us a CARB # so they would be emissions legal. After 3 days of testing we were notified by the state that the AFR heads provided a decrease in total emissions AND an increase in fuel economy by 2-3 MPG!! Also, the peak power output of the vehicle had increased by 20 RWHP compared to the stock LS6 engine configuration. Don't forget that these are just "peak to peak" gains, and much like the previous test, there were additional gains higher up past the peak HP figures. Whats important to note here is that we went up against the higher flowing LS6 head in this comparison and this test was conducted thru the factory exhaust manifolds and the factory airbox....the true potential of the AFR heads were certainly going to be "stifled" in this type of situation.

Two more quick things....during our SuperFlow Engine Dyno testing mentioned earlier, we also had the oppurtunity to test a popular Stg 2 factory ported cylinder head that we secretly purchased brand new specifically for this test....It had a 228 cc intake port and flowed in the low 290's on our test equipment (claimed figures were of course MUCH higher, not to mention the low and midlift #'s were quite abit "softer" than the AFR 205)....On the same day, with the same dyno and the exact same conditions and parameters, that head provided an increase of 23 HP (tuned and optimized) over the stock headed baseline (peak to peak numbers). That would be exactly 14 less HP than the AFR 205 headed combination, and much like you would expect, the bottom and middle of the curve looked MUCH different than the AFR 205 gragh, showing a decrease in power and torque from the "baseline" stock headed numbers until the engine was revving past 3200 RPM's. The "average" power and torque gains the AFR headed engine showed over the ported factory casting was more than just 14 HP but unfortunately I don't have those figures....there was alot going on at the time and I didn't record that information.

If you would like to see more information pertaining to this dyno test, feel free to visit AFR's website....I will try and edit this post soon and provide a link to the article on our site if I can.

Aren't "facts and figures" more interesting than silly bashing and bickering!

Amen...

Tony Mamo
AFR Sales / Product Design
(818)890-0616 Ext. 109

 

I do not understand why you are always on the defensive about your companies heads. I spend a lot of time reading this forum and in a lot of your replies I sense a lot of anger and frusteration from you. I appreciate all of your technical post and all of the research you guys have done for us, but I just can't understand your frusteration.

You guys make a great aftermarket head for the LS1 and provide many benefits to the LS1 community in your testing and products.

Keep up the good work and try not to worry about what everyone thinks.

P.S. I love my AFR 205's on my forged 346!

Cheers.

 

I couldn't agree more and although I am sorry you have to constantly prove your worth time and time again, it does give us a chance to learn more about what a wonderful product you have built.

My AFR205s will be installed in a month or so, can't wait!

Keep up the great work Tony

 

Excellent work man. I wouldn't say he is on the deffensive but is just simply pointing out the little facts the people miss when they say this head only makes such and such power so on son. I look forward to the results of the bigger heads.

 

Tony,

A lot of us are building 408 strokers. Could you give us some idea of what kind of hp increase with the new afr225's. Any comments that you can share with us.

 

Tony, I'm sorry but I really dson't have the background to contribute in a significant way to a purely "tech" discussion. I have done my very nest to read ALL posts about ALL heads and tried to take into account the wide delta between fact and fiction; myth and reality; subjective opinion and objective testing.

Based on LS1Tech.com research and talking with people whom I trust, I'm ordering "205" heads next week and will mate them with a custom Comp 220/224 XER 112 cam, QTP long tubes, and an LS6 intake.

I'm counting on you guys as well as all of the other aftermarket suppliers that I have selected.

PLease keep posting the results of your tests. Even though I have made my decision, your posts will help educate those, like me, who need objective results to aid in the decision making process.

 

Thanks for your "vote of confidence" if you will and I'm sure you will love the heads. Feel free to share some of your initial thoughts after having a chance to look them over.

My only question to you is why not go with the AFR "street cam" we spent days on the dyno perfecting...your choice of cams is so close I would be thinking it makes more sense to go with a "proven" combination....That was one of the fundamentals and goals of all the testing we did....To offer you guys a few "packages" to help assure you got the most for your money by helping to provide you with the best results possible. In my opinion, your cam choice will have more low RPM torque (up to say 4000 RPM's), idle about the same (possibly worse), and give up at least 10 HP past 6000 RPM's....perhaps as much as 15 depending on what ICL you decide to install yours.

If your driving a heavy GTO and want to maximize the "around town" portion of your power band it might make sense....I'm just not sure of what your trying to accomplish....bottom line, feel free to contact me if I can offer you some advice or assistance

Good luck with the AFR's...

Regards,
Tony

 

Looking forward to adding a set in a year .M1key99ws6 is a friend of mine and based on his experience when the 02 is paid off. I am going to the best bang for the buck short block and a set of these heads for my new setup.

 

Tony, because of my job and corporate life insurance, I cannot, in any way, "participate in organized motor sports" in concert with many other resitrictions. -- it goes with the job. My goal is to buld a car that is VERY fun to drive and would run mid 11's, if I was allowed, at the track.

I have actually been working with my H.R. guy to find a different carrier for our D&O life policies. He knows that he needs to find a high quality insurer that will allow me to race. If so, I will swap the cam for the 224/228 cam.

Those that know me well, know that I am of the opinion that it is worth it to pay for quality. That applies if one is buying racing components or if one is "buying" skilled employees. That is why we are recognized as being the 3rd fastest gowing business in our home state. Frankly, I could have gone with any combination that I wanted. I wanted what I believed to be the best and I went with a short list of products/vendors that meet my personal criteria for excellence.

It's been my experience over the last 247 years ( ) that most people will defend to the death whatever their personal choice was, be it auto parts, a school, a career, a favorite bar, etc. simply to convince THEMSELVES that they made the right decision. In other words, if one can convince others to make a similar decision, those actions reinforce one's own decisions and sense of self worth. So much for arm chair thoughts.......

I do appreciate AFR and some of the other vendors active on LS1Tech.com for sharing their knowledge and experience with those of us who lack the knowledge, wisdom, and experience that is gained in the trenches.

 

I think the main reason the x brand head didnt do as well in the testing is loss of port velocity because of the 23cc larger port. I said a while back that it was going to be hard to improve on the production design- which you have- I was more meaning the aftermarket ported offerings. What I feel AFR has done by designing the 205 head is to offer an affordable new casting that does as well as 99% of what is available by the x brand ported stock castings with a smaller, more closer to stock size runner for more port velocity for better all around power and performance. The "larger" x brand head would need a larger cam for it to show its potential- which is why I like the idea that you all there at AFR chose to stick with the stock shaft to show the potential of the 205 head, imagine the power increase it would show with a traditional and popular 224 grind in it and the difference it would have with that same x brand head. Great job to you guys at AFR for doing your homework and testing. With that x brand head flowing low 290s I imagine that it was close to the top of its class in the aftermaket ported head arena- so probably most of the heads out there you have tested that advertise 300+ but on AFRs bench only does 280ish. Interesting to say the least.

 

Tony-

I'm impressed with the results... but when will we hear about a test of the 225's on your Corvette (stock shortblock) and overlay that dyno graph against the 205's? That being the only change from its current combo and of course tuning it further to get the A/F ratios back in line.

I want to buy some AFR's.... but want to get the right ones.... when will we hear news about the 225's and dyno results with a stock based shortblock? I'm dying over here...

-Mark

 

I had a VERY nice, VERY expensive set of S2 heads sitting on my work bench a few months ago. I saw some of Tony's data on Z06.com along with some of the numbers the Z06 guys were getting from the AFR 205 heads.

I sold the S2 heads and WILL be buying a set of the AFR 205's for my Z28. The gains the Z06 crowd has been getting from the AFR 205 heads is damn impressive. Torque is king and I think these AFR 205 heads will torque monsters for the street.

Tony, if you need an Indiana test mule, send me a set of your heads and I'll test them for free on my car.

I'd be happy to do some back to back testing for you.

 

First of all, thanks for the great info Tony.

I'm in the same boat as gnx7. I want a max effort stock bottom end H/C package, naturally aspirated. However, in the future I might want to increase the cubes to say 383 ci. My personal instincts are telling me to go with the AFR 62cc 225 heads but a well respected vendor has recommend some hand finished 205's for the stock bottom end effort.

However, I'm thinking if I went with the 62cc 225's, they would perform almost as well as some hand finished 205's on a stock bottom end LS1. Better yet, when I do increase displacement I wouldn't need a new set of heads because they would be perfect for a 383ci motor. Am I on track here?

 

Tony, how much CFM was gained over the stock heads? Looking for something to compare these to other ported heads. Peak to peak at the same lift?

 

To answer my own question, I just found this on another thread...

So now I'm convinced I should go with the 225 62cc chamber heads. Only question now is what compression ratio should I shoot for? Remember, for now I am looking for a max effort N/A stock bottom end but a year or two down the road I may decide to go with more displacement.
.
.

 

Tony, thank you as always for continuing to post on our site. Your information about AFR heads has been invaluable to the community and very few if any manufacterers or vendors share as much info as you do. As far as Tony having to be "defensive about your companies heads", I believe he is just making sure that for people who havent read his other posts that the correct information is out there and isnt misrepresented. Please continue to keep us up to date, many people on this site appreciate you sharing your work, theres more then negative people here.

 

Do the unmilled AFR heads have the same size combustion chamber as the stock heads? I thought at the AFR heads had a LARGER combustion chamber.
Phil

 

Phil...

AFR 205 come "standard" with 66 cc chambers only.

AFR 225 come "standard" with 72cc (currently available) or 62 cc (a month or so out).

Obviously any "standard" chambers can be milled accordingly for less volume to dial in your exact combination for the compression ratio you desire.

"PewterZ28"....call me at AFR and I can handle all your questions one on one and get you headed in the right direction.

Thanks Guys...

Tony M.
(818)890-0616 Ext. 109

 

*** Counting days until I switch to AFRs

 

I know Tony made a believer out of me. (Thank you Tony )
If only my tranny didn't take a dump this Summer, I would be enjoying a nice set of AFR's too