Patrick G

iTrader: (14)

That's part of my nitrous kit. I have not run nitrous through this new motor yet. I'll need a better setup (stand-alone fuel system) before I consider spraying anything bigger than a 100 shot. Spraying a 150 shot during the Texas Mile was very hard on my motor. Short bursts with nitrous are OK, but pulls to the top of 5th gear take their toll. I'd rather not have Erik Koenig on speed-dial, LOL.

99blancoSS

iTrader: (115)

Nice writeup Patrick. I was looking at your sig and saw the 500 last night and was wondering when you did that.
One thing you need to add to the list if it isn't already there is a stock 10 bolt rear-end and factory wheels.

I havent seen one hi power combo yet with a 9" rear and that goes alone with reducing rotating mass.

You also went from a small cam to a big one. Maybe my lack of power is the 234 cam when all the big numbers are by cams in the 238-242 range?

NC98Z

iTrader: (1)

Damn that pesky power under the curve! Patricks gone to the dark side! Lets see now I gotta get am aluminum driveshaft and an underdrive pully. You know I got my new GMHTM in the mail last nite and in one of the ads they were claiming 500 hp with this little graph about 2"s square and i didn't look at it anymore. However when Patrick posts up a 500hp thread I believe it. keep talking son wre writting this stuff down!

SSpdDmon

iTrader: (10)

If you don't mind me asking....you said you had timing @ 28degrees for peak torque and 30degrees for peak hp. Where is it at before and after each of those? If you run EFI Live, I'd love to take a peak at your tune.

Patrick G

iTrader: (14)

With my old 223/227 110LSA cam, I ran 26 degrees of timing at peak torque and 29 degrees of timing at peak power. The new cam doesn't make as much cylinder pressure and likes a little more timing.

SSpdDmon

iTrader: (10)

Cool. But, I was talking more about before and after peak torque. In other words, from 3600~4400 and 5200~6000 assuming that you have 28*@4800 and 30*@6400.

99blancoSS

iTrader: (115)

And so what your saying also is that Tony was able to drasticaly improve the flow in the low's by unshrouding the valves alone. He didnt touch anything else? Did you go to bigger valves? Its hard to read back while I'm writing but I'll look after I post.
As you know I'm extremely flabergasted with my results. I'll post the graph when I get it back in my thread.

I'm just looking at all you did and trying to compare it against my car and see whats up.

PunkNPonys

iTrader: (2)

Wow, very nice informative write up. Thanks for sharing your ideas and your setup with us. There is not to many guys that would do that.

Patrick G

iTrader: (14)

Tony did not touch runner of the port and the valves are still the stock 2.02/1.60 size. He opened up the chamber size from 3.900" to 4.000", he revised the valve job to increase flow at the low and mid-lifts (which hurt the flow above .500"), and he hand blended the valve job above and below the seat to insure solid flow in milled form. This is by no means an unmodified AFR 205 head, but more of an example of what Tony does to the 205s to get them to work better with large bore motors (like 402s). Based on the success of several 402/408s and now my small bore motor, AFR will most likely incorporate the tweaks into future sets of 205s. Hopefully Tony will see this thread and chime in.

KCS

iTrader: (20)

Tony,

How did you get those numbers as to where the manifolds "lop off" the airflow?

KCS

iTrader: (20)

Sorry, I mean Patrick.

Patrick G

iTrader: (14)

Years of flow testing. Keep in mind, just because a manifold lops off the airflow at 280 cfm does not mean it won't flow more than that. It's just that it becomes more difficult to get gains above that point. Sort of like restrictor plate motors. Even though the restrictors cut down flow potential, there are still gains to be had with better cylinder head flow. The better the heads, the faster the cars went.

An engine will still make power pulling a vacuum at WOT. My engine pulls 1.5" of Hg at WOT in the higher rpm ranges. Need to find the culprit.

drain89

iTrader: (13)

Excellent Job!

magius231

iTrader: (8)

might be worth a sticky seeing as how many "how can I get 500rwhp" threads pop up here...

a-low

iTrader: (26)

Hey PatrickG how much flywheel hp are you making?
Also whats your mpg on that setup? It may not be a concern when making 500rwhp but just curious.

dyls1

iTrader: (11)

I agree, but locked and only with the "recipe" and not a bunch of replies clogging it up (such as mine here, lol)

Great write up Mr. Patrick G!

Patrick G

iTrader: (14)

I think the power loss through my 10 bolt and accessories is around 60 hp. So I'd guess the flywheel power is in the 560-570 range.

Interestingly, my fuel economy has increased since I've swapped back to the AFR 205s. I'm getting 26-27 mpg with the new heads and cam. That's a gain of at least 1 over my old 475 rwhp setup . The high airspeed of the 205s is really good for gas mileage, in fact, when CARB was doing their certification for the 205s, they found that they got a 2 mpg increase on a stock Z06.

Tony Mamo @ AFR

iTrader: (13)

Wow...

This thread blew up quickly....LOL

Ive been away most of the day dyno testing and just got back. I dont have much time now but wanted to compliment (and congratulate) Pat on an excellent write-up and impressive results. We had discussed this project at great length some time ago and the results certainly make a case for alot of the theory I have been preaching for some time. The obvious being that once again the AFR 205 emissions legal stock geometry head can deliver the goods (with the right supporting mods and tune) and it is simply the right choice for any N/A 346 from mild to wild.

Obviously this wasn't an out of the box 205 and I spent a fair amount of time optimizing it for the low and midlift flow Pat has already touched on. Between you and I most of the ports in Pat's head fell short of 300 CFM @ .600 lift usually peaking at that number closer to .575 and falling off slightly. Put a manifold in front of that head (not a radius plate) and install it on a running engine and all bets are off. Strong average airflow (killer low and midlifts) and a proper cross sectional area which promotes airspeed and stonger cylinder fill momentum (energy) is where its at. Dont get me wrong, you still need solid peak numbers but not at the expense of the curve.

Also, I have seen higher than 280 CFM with a few of my recent ported FAST efforts (over 300 actually with a 330 CFM port) but none the less the point Pat is making is still valid. A huge port with "OK" low/midlift flow and an intake that will knock down a sizable percentage of where that head shines will leave you with poor velocity and mediocore results because the average airflow with the intake in place may not be much more than a smaller head with better lows and mids, but the big head still has the big lazy hole to activate and get air moving thru.

Anyway...Ive got alot going on this weekend. I will try to keep an eye on this thread and post accordingly as soon as I can.

Killer results Patrick....and the way it carries power is a thing of beauty!



Regards,
Tony

PS...Chalk up another solid combination for the "blue pill" crowd

AdamSS

iTrader: (3)

Awesome reading material. I say STICKY IT !

LowBird

iTrader: (1)

great numbers! very informative.