McRat

They are well packaged, very well machined and almost too pretty to go on the Meanie. Extra cool AFR CNC engraved logo adorns the ends of the heads.

We opted for a mild 224/228 cam to keep the main purpose of the car intact. The car is a 10,000mi a year grocery getter.

After initial tuning by Steve Cole, the car is... uh... provocative. Traction is an issue on street tires. But the car pulls strong from 1500, idles at 900, has excellent grunt at 2500, and gets very serious at 4000. OH HELL happens at about 6000, and keeps making power to 7000. Certainly we need not fear stock Vipers on the freeway.

On street tires, it roasts the tires in 1st, 2nd, and 3rd until you lift.

We opted for a 112 LSA to widen the powerband and give it a little lope at idle. Even through stock mufflers, it sounds pretty mean.

Hopefully we can find a dyno open tomorrow and post some "preliminary" numbers. The car is not tuned "on the edge" yet, and I imagine after Kentucky we will find more power by tweaking it.

PREDATOR-Z

Congrats,

I'm waiting for mine.
How about a Dyno??

McRat

Dynos on Sunday are to find here. We'll do our best.

I must say AFR did a spectacular job of customer service and provided us with everything you need to get the job done. The "Janitor" at AFR went the extra mile for us.

Mirek

Congrats.
What is the lift on that cam ? Is there any good reason not to mill them for more compression ?
I thought the AFR's stock would provide in the area of 10.2:1

PREDATOR-Z

10.25, I think a little more with cometics.

i'm getting mine milled to 62 cc (11:1 CR with cometics) but the highest duration i can run is 224 (witha good margin) without flycutting pistons.

CHRISPY

Great stuff

Couple of questions for you...You mention stock mufflers?

Do you have cutouts on the car and longtubes? I'd like to see a full run down of the mods currently on the car please

JBsC5

Awesome..

Glad to hear your so pleased with the AFR heads...

Can you give insight to what you feel is the reason the 224/228 is a better choice then the 224/224 cam...combined with the afr heads?

10rwhp differential expected or more dramatic?

McRat

Contact Tony at AFR concerning milling and valve clearance. Even though I had some valve clearance, I notched the intake side just a little (.050") to play it safe. The cam lift is ~.588 if I recall. Valve control is Comp Cams 921 doubles with ti retainers and lightweight valves (I forget the valve mfr), stock rockers. Comp 7.400 pushrods were correct for my 0.040" mill cut. Motor was spun to 7500 to see if it would break, but we are going to shift at 7000.

Injectors were AC Delco 38lb pieces.

We put on a FAST 78mm intake. My opinion is that it is not ready for prime time yet. It did not fit well, no gaskets, missing C5 features, whistles, had flash, etc, etc. Took 2 hrs just to get it on after "customizing" it. But I figured that it would be better than a LS6 manifold for 4500-7000.

Previous mods were Kook's 1 7/8" off-road, ASP pulley, Halltech air filter (not worth it).

It is running stock Z06 mufflers. Quiet and stealthy. No cutouts.

We are going to dyno it with COLD A/C, full mufflers, and no dyno tricks. But keep in mind we did a rough "street-tune" only and didn't get time to dyno tune it yet.

PREDATOR-Z

So you milled them .040?
That would give you around 60cc.

McRat

All the GM race grinds favor more exhaust duration. I'm of the belief that GM knows more than I about it. The cam has 112 LSA and was set up +2 advanced, so it's exhaust valve closes almost the same time the 224/224 does. You could almost think of this as a 225/225 with moderate overlap that favors the exhaust.

This setup pulls strong to redline, so a 224/224 would probably be great as well.

JBsC5

Thanks for the headsup!


JB

Tony Mamo @ AFR

iTrader: (13)

JB,

The cam in the "AFR Silver Coupe" IS a 224/228. The only difference being I went with a slightly "stealthier" 114 LSA trying to appeal to a broader market (and power band for that matter). Was looking for "stock-ish" idle and big HP all wrapped up in one.

The 112 LSA and more advanced positioning of the cam ground for "McRats" application should provide Pat with more torque in the middle of the curve to better recover from the big 3-4 RPM drop common to the Z06 M12 transmissions. It will idle with a little more lope than its 114 brother and should provide a power curve a little "fatter", although "peakier", and a slightly more NARROW power band.

The 224/228 on a 112 is also a "custom grind" available at AFR and is a good choice for guys not focusing on "as smooth an idle as possible", and is a great choice for the Z06 guys or anyone with an M12 Trans.....It is still a relatively mild cam very much suited to a daily driver.

Pat, I am glad to hear the car is up and running again. Hopefully you can get to a dyno soon for some further tuning and tweaking and get us some numbers. Best of luck in Bowling Green!!!

Regards,
Tony M.

McRat

Thanks for all your help Tony. Let me know when you want to line 'em up. I bought a new license plate frame and want to show it to you. Bring binoculars.

Tony Mamo @ AFR

iTrader: (13)

I will....But I will be pointing them in my rear view mirror

Anytime....Anywhere

Count me in!!!

I know the perfect spot....The "AFR Janitor" can flag us !!

Congrats Pat....Sounds like your real happy with it.

Regards,
Tony

MelloYellow

Sounds great. My AFR 205's go on this week in an FI setup.

Did you say you milled .040" and are using 7.400" ?
Isn't that a bit too long on the pushrods with the milling?
I'd have thought 7.350".

McRat

Base circle is smaller on the cam. It didn't float at 7500, so I'd say it's good.

McRat

You have no "dice" dude. It will get ugly. My dice were custom tuned and dyno'd at 75HP/106ftlb!

When we get back, LACR. I need to buy a camera mount that points backwards though. I guess they are special order.

Oppss! Need a telephoto lens too! I'll order that also.

McRat

PS - I get the "right" lane, tower side. It's my lucky side.

Oldtexan

So what is the largest lift you can run with these heads without cutting the pistons? Us home mechanics want to know

McRat

It's not lift, it's the ramp design and intake valve open event. You can bang a piston with a "mild" cam and a stock head. The LS1 is an interference engine.

Here's the rub - Anytime you run a larger than stock cam, you MUST check Piston to Valve clearance. I'm willing to bet 1/2 the guys who are reporting broken valve gear that are running a cam had a collision.