AFR 205's really shine on mild applications (wild too but the difference is greater between stock ported castings and our clean sheet design in milder applications).

The throttle response, tip in, fuel economy, and of course power are all significantly improved. With a cam and some longtubes (that can be removed come smog time) the before and after results are dramatic. After having experienced the package I am highlighting/suggesting here trust me you wouldn't want to drive it stock another minute.

Sure its not cheap (to do it right) but the experience is akin to driving a new stock 427 Z06....you just saved 40K by doing it yourself in your paid for or close to paid for C5.

If you add a ported FAST to the mix, even my smog approved cam choice would clear 450 RWHP.....425 or so without the intake.

Its simple, reliable, quiet, and stealthy, and you don't add 100 lbs of blower accessories over the nose of the car upsetting handling and braking in a negative fashion.

While I appreciate the simplicity in building power with boost, a good N/A build provides immediate thrust and has much sharper part throttle response (a very bonus perk IMO). Unless your actually on boost, spinning a blower assembly is simply detracting from your overall power output and fuel economy as it takes a fair amount of HP to drive it....that much less making it to your rear wheels.

No different in a higher output car btw.....my buddies C5 with a ProCharger made 80 more RWHP than my fairly aggressive and very optimized 383 N/A build. We are discussing a 540 RWHP car versus a 620 RWHP....sizable difference just gazing at the numbers. We would go from a roll and I would instantly put 2-3 car lengths on him. He would catch me about 110 as I was grabbing fourth and finally start pulling on me as the triple digits started piling up furthering the gap at triple the legal speeds of course (long past the end of a quartermile blast). However, the "feel" of my car around town at part throttle and even grabbing a few gears WOT quickly was ferocious compared to his.....my car seemed and felt night and day faster. His power delivery at part throttle and quick WOT blasts was just lazy in comparison although some of this likely due to the A4 trans versus my manual. Its that part of your driving though that a good N/A package really shines.....and lets face it, for most of us it makes up 90+ percent of our driving time behind the wheel.

These are all important considerations to think about when exploring the type of mods your considering for your ride. While ultimately the blown combo has more potential (especially combined with good heads and other go fast goodies included in the mix), if your keeping your car relatively mild (under 500 RWHP) a stout (optimized) N/A combo should be given strong consideration.

Just my nickels worth of free advice on the subject....

-Tony

 

Thanks Tony, I appreciate your opinions and insight.

 

I would LOVE to drop an LS7 into my car... Here's to hopes and dreams! LOL

It'd take me a good 8 months of being on an extreme budget to save up for an LS7. But I know it'd be worth every penny.

 

Dreams are good and I hope you get yours. Keep in mind though the LS7 is just the first of many items that would have to be changed unless you babyed it and what fun would that be!

Things like ouput shafts, clutch, diff and other items would need upgrading to handle the extra power.

If I were to switch engine I would take a hard look at the new LS3 that is producing 480 HP. Its price fits into my budget much better the the LS7 and all the other needed items. JMHO

Tony! Nice write up. What would you expect the mpg advantage be with the head change you wrote about?

 

I saw a two MPG increase with my 346 CID AFR 205 package and a slightly larger 224/228 cam.....a smaller cam that would pass emissions such as a 220/224 would have less overlap and produce even better MPG figures. Easily worth another point if I had to guess. That represents a 15% increase in fuel economy....not a bad perk while picking up over 100 RWHP if you set the package up correctly.

Its a win-win combination.....besides the cash outlay for the package you cant find a bad aspect of this swap....thats the real beauty of it. It simply acts like the way you wish you could have bought it right off the showroom floor!

Perfectly docile, excellent driving manners, and with a set of sticky tires capable of running the quarter deep in the elevens in the low/mid 120's depending on track conditions and how close to sea level you live....



-Tony

 

What kind of cost are we talking about with this set up?

Some of my friends has seen this post and they are interested. Also is there a LS2 equivalent application?

Thanks for any feedback you can give me.

Feel free to PM me.

 

Highlighting the larger portion of your expenditures would be as follows:

AFR 205 Heads milled for higher compression $2400
Custom cam $425
Lifters $250
.040 thick head gaskets $155
Long tube headers/exhaust $1200 - $1700 depending on choice
UD Pulley $250
Install and tune $1500 ish (that can vary alot)

Optional

Ported 92mm FAST and ported TB (add 20-25 RWHP) $1900
Electric water pump $500 (adds 5 RWHP)
Yella Terra rocker arms (adds 5 RWHP and triples valve guide life) $475
Additional hand work on the 205 heads $850 (add 12-15 RWHP)

Regarding a similar package for an LS2, I would simply step up the cam about four degrees to cover the extra displacement. If you had to pass smog that would limit us to a 224/224 single pattern or a 224/228 on a slightly wider LSA.

If any of you guys are really serious about this we can better discuss it over the phone but this should give you an idea (or at least a rough idea) of most of the costs affiliated with the swap. Like I said, its not cheap but it transforms your engine/car into a completely different animal.

Here is an in car vid of my "Dr. Jekyll/Mr Hyde" 346 package in my C5.....most people I took for a ride couldn't believe it had the stock 346 GM shortblock. Note this was a slightly larger cam than I would run or recommend in a car that must pass emissions and has no way to circumvent the system if you will and of course I had all the little extra go fast goodies to completely optimize my package, but it will give you an idea of how much different your car could behave if you spent the money. Note how smooth the idle is just before I stage and bring the rev's up. This was a low eleven run @ 124 MPH with a positive 1600 D/A....not the greatest air for making power and getting an optimal timeslip but certainly not the worst either....LOL (I feel for you guys that have to run at really significant elevation!). Note this car still clocked 30 MPG cruising in 6th gear (with a 3.90 rear) on a pure highway run.

http://www.carcraft.com/multimedia/v...deo/index.html

Cheers,
Tony

 

Thanks for the quick response Tony!

My timeline is not immediate. Maybe get serious in about a year, adding a few parts along the way. Just need to get my ducks in a row, and my mod account.

 

 

Just an FYI that an LS3 headed engine (especially one on a 346) will never touch the power delivery in the lower/middle RPM's of the packages we are discussing.

They have a huge intake port and a big valve and simply don't develop enough airspeed to be effective there....especially when your looking at weighing low RPM response, top gear tip in, etc.

Also, these heads aren't miracle workers.....they need cams and the typical go fast parts to put up the big numbers. The reality is looking purely at design, they are not particularly efficient heads by any means.....just a reasonably cost effective route to achieve a large peak number on the intake side but making power is related to alot more than just looking at a peak intake number (airspeed, cross sectional area, low midlift flow, etc.). They are also very unbalanced design (for lack of a better word) because their exhaust ports are very weak which now mandates the need for more exhaust lobe in the camshaft to crutch that situation....thats adds additional overlap in the cam and overlap is the enemy of MPG, low speed power output, and good drivability.

-Tony

 

The engine is but a straw - sucking air all the time - the fewer "pinches" in the straw the more air gets sucked through. Headers at one end of the straw - American Racing Headers (mine are another brand!! -wish I had these) are the ones to go with.

At the other end of the straw I had to add the LS6 intake manifold. I went with the 243 heads cnc'd to 300cfm flow at .600 - call Gunter at Patriot Performance to find out if he has the California thing beat. You'll like his price and the heads as well (mine are also 62cc w/ double gold springs -chrome moly rods) -my cam is only 218/224 lsa 115, but Comp Cam has this "fast ramp up" lobes that open the valves faster -you need to ask them about it

my car is not exceptional - but 2000 coupe that goes 11.83/116 mph in the 1/4 mile w/ 1.67 sec 60ft time - it jumps pretty good and still gets 28 plus mpg on the highway

big straw is a good thing!!
Oh yes, Tony knows way more about this than I will ever dream of knowing!!!

 

Tony, in your last post it sounded like you might be talking about bolting a set of LS3 heads on an LS1 or were you saying that an LS1 has better potential for a performance daily driver than an LS3?

 

Currently I'm on my 2nd C5 ZO6 and my last one was a h/c/i combo. If I was in your shoes with a LS1 Vette, I'd just port the stock heads and put in a cam.

Both Patriot and MTI do really good P&P work and my understanding is that there isn't much of a difference in performance between the 241 and 243 heads at all when P&P, with the exception of compression (you can always mill your 241 heads).

You want more power? P&P and mill your stock heads and add a cam along with any necessary supporting mods. You'll still make 430+ rwhp smog legally (good tuner of course) without spending a extrodinary amount of money.

Either that, and/or gears and a good tire!

~Seth (from SD also)

 

and the low RPM response is the OFF the LINE our OUT of corners quick response we all look for.

 

Biggest problem with that is most of the budget ported stockers need at least 230 cc's to flow a peak number of 300 CFM or so.....some are larger and still dont achieve that figure and their typical low and mid-lift numbers are usually off an AFR piece by 10-15 CFM.

The 205 AFR achieves the magical 300 CFM mark by .600 lift (a number that used to be the benchmark of a 23' race head at .700 lift)....hell it flirts with 290 CFM as early as .550, and does it with a 205 cc finished port volume. The key to that happening was adding material in all the right places in the original design....not just removing. Thats the big benefit of the clean sheet design....a benefit you simply cant have with a factory ported head even if God himself came off his mountain with grinder in hand.....unless he was also dragging a welding cart behind him or a bucket of epoxy you would be SOL.

It's the same reason the AFR headed engines have so much more low RPM punch and also the same reason they generally make more peak power as well. Same argument regarding the exhaust port which I really never touched on....the clean sheet design flows more air thru a smaller opening....higher velocity and a better draw to help the next intake charge into the cylinder is your benefit there....as well as obviously exhauisting more air in total.....once you cant properly evacuate the cylinder, your next intake charge is diluted and your power curve starts nosing over.

While some my view this as a shameless plug for AFR's, I hope the smarter among you realize all of this info is spot on in its accuracy and very applicable to the milder performance packages we have been discussing where airspeed and efficiency become of much more importance/relevance.

As another point of reference, the better factory castings (243 LS6) flow in the 250 CFM range at their out of the box volume of 211 cc's. Before anyone even touches them with a grinder in an attempt to find alot of air they are already 6 cc's larger than a finshed, repeatable AFR 205 cc intake port flowing 300 CFM. The stock LS1 ports are about 200 cc's and usually flow in the 230 CFM range.....once again I mention this to help you guys better appreciate why the clean sheet design is such an advantage.


Actually I was more referring to people considering the swap to an LS3 head on their LS1/LS6 based cathedral headed shortblock....

Thanks,
Tony

 

Thanks for clearing that up for me.

 

Tony,

For what it's worth, I'm enjoying the head information you are suppling. I do have a few questions if you don't mind. Is there a downside to the AFR design compared to the stock heads? The reason for my question, why wouldn't GM work to improve the head flow to come closer to what AFR has achieved? It seems the fuel economy advantage you mentioned in one of the earlier post would be reason enough for them to pursue improving flow. What about overall durability? Would I expect AFR heads to last longer or not compared to stock heads? Any difference in cooling passages that cause them to run hotter or cooler?

Thanks,

Eric D

 

Eric,

Good question actually....and I find its a more popular question posed to me by "non car" people when I try to explain to them what I do ("Why didnt GM just do it that way??"....LOL)

I guess had I gotten a chance to bend Dave Hill's ear some 15 years ago....well....lets just say I might not be posting here.....LOL

BUT, that also assumes that I would of had all the same time and resources working at AFR provided for me, not to mention the basic architecture I already had to work work (a uniquely shaped cathedral port with 15' valve angles, etc.).

Even the CARB board who ultimately tested and approved our heads for emissions legal status said they were very impressed with the design. They ran the test car we set up with our heads thru numerous real world road simulations (extensive chassis dyno/load cell type of testing) and noted not only did they see better fuel economy, but emissions were better than OEM and obviously there was an increase in RWHP as well. That was really about as good a testimony to their design as you could get Im thinking.....besides all the real world independent feedback found here and other popular performance message boards of course. I remember like it was yesterday when Rick (AFR owner/President) shared that info with me....it was one of the highlights of that product development for me (almost as good as tearing up the road with them after rolling off the chassis dyno for the first time!).

Bottom line is we invested a ton of time in already proven solid platform that really was a huge leap forward from the 23' stuff GM was producing back in the day. Perhaps given more time their designers, engineers, may have improved on it further and technically they did with the LS6 casting gaining 20 CFM with only an increase of 10 cc's of port volume, but the AFR clearly steps the efficiency into a completely different league with less volume and significantly more flow.

Other aspects worth considering is strength and obviously our aftermarket casting gets the nod there as well with twice the critical thickness in the head deck area (.750 compared to .350 or so stock).

The ONLY slight negative I could think of which is technically a positive in a performance head is the use of bronze guides. The upside is the increased lubricity that material provides....the negative in an OEM environment would be wear.....a bronze guide will never last 100,000 miles like a steel OEM guide would, but half that figure is certainly reasonable to expect with good valvetrain geometry. Alot of this depends on spring pressure, cam intensity, and application, but the reality is most aftermarket heads have bronze guides because in a high heat high load situation there less likely to stick a valve.

Probably more info than you needed but I really wanted to think about a potential "negative" if you will associated with an AFR install and thats about the only remote honest answer I could come up with.

Hope this helps...

-Tony

 

I was talking about a new engine (ls3) not Ls3 heads

 

I know we are talking about cams that will pass CA, but just in case you wanted to see some other numbers, here is my set up:

01 MN6 Coupe

AFR205 heads (not milled or worked , stock out of box)
Comp cam 228/232 .588 .590 113 LSA
Stock LS6 Intake

I put down 410RWHP (with 390 gears mind you , so it might be a bit more)

Other supporting mods are

Dynatech Longtube headers
Vararam Intake (with halltech stinger duct)
160 Tstat

My car really starts to come alive around 3krpm...once you hit 3500 she is really pullling. So figure with my whole set up I picked up about 100RWHP.

Just my .02