Tony Mamo @ AFR

iTrader: (13)

And I'm not impressed nor do I appreciate the tone of both your posts....but especially this one. Build a similar displacement (mild) combination and bring it on.

This engine would produce close to 520 RWHP and 510 RWTQ if installed in my C5 driveline with 3.90 gears....and it idles like stock.

I will address some of the other questions and issues that were brought up later....kinda buried right now.

hammertime

iTrader: (1)

Seriously? Nearly 1.5 hp per cube from what is generally accepted as a daily driver cam for a 346 is pretty damn good! I think you might possibly have missed that Tony did not present this combo as a world beater or record contender.

I think all would agree that another full point of compression and a different cam could extract a lot more potential power out of the setup presented. It's not like every 402/408 out there has put an easy 500rwhp on the board, let alone with a baby cam.

Roy V.

iTrader: (1)

Have another cocktail ............

1QuickT-A

iTrader: (12)

Awesome job from Tony as usual! Congrats to Roy V. on a killer engine combo for his GTO!

Tony Mamo @ AFR

iTrader: (13)

Aight...

Let me hit a few of the questions in here....and even Flow Wizard brings a few points to the table I will address....it was his manner in bringing them that wasn't called for. Alot of hardwork went into the results brought forth here....a little more respect and professionalism would be nice no matter how you feel about the numbers. But hey this is the Internet....chock full of "experts" and their opinions.

Anyway....a few good questions were brought up. Will we be digitizing some of the changes I performed to these heads so they can be purchased that way thru AFR? The answer is yes....the bigger question is when and that is what I cant answer....best guess would be before the end of the year but it could be sooner or it could be later. What I'm referring to here is mainly the chamber mods which in and of itself made the largest impact on the final numbers. The chamber is reshaped to optimize the larger 4" bore which increases the volume by about 2.5 cc's. We will ultimately offer a 205 with a 68 cc chamber optimized for a 4" and larger bore motor. The rest of the work performed is all detail related looking for a couple of CFM here and a couple of CFM there, not so much removing material and enlarging the runners. If the intake and exhaust ports were a cc or two larger than before I worked on them I would be surprised. I designed the product....and production is production. Knowing what areas to romance is thee quarters of the battle....perfectly blending the valvejobs into the bowls is a critical type of thing....remove a few thou too much and you just hurt flow by increasing the throat diameter. Blending the top cuts of the valve jobs into the chamber so it is seamless....these types of things are impossible to do in a production environment yet someone tackling these tasks to aggressively could just as easily loose flow hence my recommendations in the past to leave well enough alone. Our product is extremely optimized piece out of the box and has proven that by producing solid result after solid result, but when looking for every last detail most production heads from any manufacturer can be slightly improved on...ours being no exception....BUT, I also feel that our heads are alot closer to optimal right out of the box.

Hammertime brought up a good question concerning my cam choice as well as provided himself with a good deal of his answer as well. I'm usually not a big fan or reverse or even single pattern grinds, but in this situation we had a head with a phenominal exhaust port due to some of the "detail work" and better chamber design ultimately leaving us with a cylinder head with an E/I ratio of 81% for the entire lift curve. That played a big role in allowing me to shrink up that exhaust lobe knowing that I wouldnt need the exhaust valve open very long to get the job done. Shortening that lobe also benefited us by reducing overlap which would help clean up and improve the bottom and middle of the power curve (a primary goal) as well as help smooth the idle at the same time (another primary goal). You can see that even with a single pattern and a baby cam the engine still carries well past peak HP, a sign that we still had enough exhaust port to properly evacuate the cylinder even with a single pattern grind. In this engine spreading the exhaust lobe may not have helped the top at all (or very marginally) but would have dirtied up the idle a bit as well as cost us some low and midrange grunt.

Meent....concerning this engines reliability over the long haul, with the exception of a potential valvespring swap every three years or 24,000 miles (whichever came first) I would say this engine would run like a top and not require anything different than a stocker (oil changes at regular intervals etc. etc.). The XER lobes have been very dependable and reliable but they work a valve spring pretty good and you couldnt expect any spring to go 100,000 miles with that type of valve intensity. This applies to anyone running and XER cam or worse an LSK or XFI lobe. Could you drive one 50,000 without a hitch....maybe....but I wouldn't want to take the chance. It's not worth it.

Gannet....a bigger engine will naturally tolerate (and need) a little more cam, but this cam (or one slightly larger) might not work nearly as well when coupled with a different cylinder head....its all about the combination which I know all of you have heard 100 times already....it just happens to be true though.

STD correction versus SAE....simple answer....that's how Westech and most dyno facilities that test on an engine dyno record their data. On the other hand SAE is certainly a more popular method of testing on a chassis dyno. I have had both of my combinations (the 346 and the 383) on the exact same engine dyno, and ultimately went back with them installed in my C5 and tested them on Westech's chassis dyno (as well as many other chassis dyno's all of which were extremely close). My delta loss from engine dyno (in STD correction) to chassis dyno (in SAE correction) was exactly the same in both of my combinations.

Eng......Flywheel......Chassis......Net Difference
CID.......HP / TQ......HP / TQ........Hp / TQ

346......550/480......475/435......75/45
383......610/523......535/478......75/45

And Roy's engine in my C5 would look like

403......592/556......517/511.......75/45

BUT....and a big but....Roy's engine would already be making 480 RWTQ at 4000 RPM's clearing my 383's RWTQ by almost 70 ft/bs and my 383 is a pretty stout piece to compare against. The area under the curve and peak TQ this engine produced on 91 octane is extremely impressive and not being impressed by these numbers (approaching 1.4 ft/lb per CID) shows a lack of knowledge or real world comparisons to draw from more than anything else.

Hell, this engine would have produced 420 RWTQ at 3000 RPM's (again....in my driveline)....a number most of the better 346's barely achieve at their peak some 2000 RPM later. And keep in mind guys....we are not talking about a 427 CID build here.

I may have to take a trip to Chicago just to experience this engine....most of my own combinations arent set up as conservative and that type of grunt in an area of the tach you can hit just pulling away from a light would have to be a blast....

I need a bigger engine.....thankfully one is just around the corner.

Sorry for the long post....I'll touch on whatever I may have missed next time.

Later,
Tony

PS....Unfortunately Roy's GTO is an A4 so we will never quite see "hero" numbers from the dyno but Im sure as A4 GTO numbers go, they will be impressive....time will tell.

Xtnct00WS6

iTrader: (8)

That chassis and flywheel dyno difference is exact across the board! Maybe I missed it, but what kind of driveline is being used? M6, 4L60e, stock driveshaft...etc?

Thanks so much for posting up the results!

thehammer69

iTrader: (2)

Tony has a C5 with 6-speed and 3.90 gears.

Hammer

Roy V.

iTrader: (1)

It's going into a 4L60e with a stock two piece GTO driveshaft so I'm figuring 20% loss with a Vig 2800 converter (hopefully).

Gotta bounce it off Flow Wizard though to confirm what I'm stating .......

Roy

Quick Double Nickel

iTrader: (5)

LMAO!!

MeentSS02

iTrader: (11)

Tony...thanks for the answers. Damn impressive no matter how you look at it...all from heads that most people (on the internet) would consider to be too small for that cubic inch build. Color me impressed, even if the interneters say otherwise.

Juiced

iTrader: (2)

No way you are lossing 20% through the drive train, Maybe if it was a th400 and a 9" rear......

Tony Mamo @ AFR

iTrader: (13)

One of the better aspects of this project is having both numbers to digest....flywheel dyno information which we have already and ultimately chassis dyno numbers. But dont kid yourself....most 500 ish HP engines lose at least 100 HP thru an automatic driveline (which would be 20% in that situation)....some 20-30 HP more than a more efficient manual trans set-up. And we have all seen even more depending on stall converter type and construction. My guess is that this engine in Roy's GTO will make mid high 400's TQ and HP to the ground (say 475/475) but there is no sense debating it because in a few months we will all find out (hopefully with a time slip not to far away from that info being made available).

Tony M.

LS1Beginner

Tony: great post. Would an engine like this be expected to pass a Ca. emissions test?

Tony Mamo @ AFR

iTrader: (13)

Thanks...

You know initially I would have been on the fence, but seeing the vacuum this engine pulled at idle (close to 15") I would have to say yes (depending on tune and condition of the shortblock...no leaky valves or rings etc.). My 224/228 in my former 346 just missed passing and I didnt do anything with the tune to help (which could have squeaked it by). This combo has slightly more idle vacuum and was even smoother than my 346 which had the typical small street cam kind of light lope at idle.

Considering Roy wasn't dealing with CA emissions, in hindsiight I would have but just a little more cam timing (a few degrees) which would have easily cleared the 600 mark on the engine dyno. If I spent a little more time that day tuning (leaning out the fuel upstairs....possibly another degree of timing up top) I could have possibly cracked 600 with his current set-up but as I have said previously, this wasn't one of those type of dyno sessions. Roy will have plenty of time to tweak and optimize the combination in his car on the chassis dyno where it makes more sesne to do so.

Tony

MeentSS02

iTrader: (11)

Tony...for reference, do you have an engine dyno printout of your 346 build that I could look at (your famous 224/228 combo)? I'd like to see what the BSFC numbers look like side by side at the different RPM points. I'm torn on doing a 364 vs. a 402/3 build...

Tony Mamo @ AFR

iTrader: (13)

Meent...

BSFC numbers would not tell you anything....build the biggest engine you can afford....period.

Assuming you are looking for a dual purpose car with a typical RPM cieling of say 7000 or so. A bigger engine with the same induction (heads, cam, intake, etc.) will make similar power to a smaller engine but have waaay more average power and area under the curve. It will also be more user friendly (smoother) driving down the road. Do a search on some of my old 346 posts if you like, but comparing BSFC's would be low on the agenda if your looking to evaluate which one would be better for you.

Build the 402....you wont regret it.

Tony

PS....If driven conservatively, the larger engine will only be slightly less fuel efficient all other things being equal (CR, head selection, cam, etc.)

MeentSS02

iTrader: (11)

Thanks Tony...that's what my gut is telling me.

Flow Wizard

why is it you use 14%, 12% d.t. loss on the same car just different engines and then apply 13% to this GTO engine? How much was the AFR's and FAST90, I missed that.

VIPRETR2

iTrader: (63)

You are a silver tongued devil! If I'm correct, Tony is representing that a given drivetrain does not rob a % of total power relative to output but always robs the same amount of power. In the case of his C5 the drivetrain loss is 75hp/45tq. I am glad to see this in reality, most people that claim a percentage of loss no matter the output do not have the engine AND chassis dyno experience to prove it. It looks like he estimated an automatic trans will have a slightly more parasitic effect on power, which is a reasonable assumption.

Proud2bSS

iTrader: (2)

That being the case, it only makes sense to build the bigger cubed motor to achieve an additional 100hp knowing that you won't loose anything more at the tires, and still be a daily driver with gobs of "usable" grunt in the daily driver power band.

That's a win-win in a street muscle car!