Greg Fell

iTrader: (9)

Dave, your valve float issues will 99.999999% be cured with the 1.7 rockers. However, as Tony said, I wouldn't expect any more 'peak' hp, certainly not the 30-40 that it is 'down' on. Time for new heads.

I've ordered the LS7 heads/manifold, and am waiting for the rockers to be available to order. Time to make some real power. They will work well on our larger bore motors, and are cheap, relatively speaking.

Also, I agree 100% with Tony. It is indeed, NOT the headers. The LG headers are the finest available...I would trade my 1 7/8 kooks straight up for them. The C5R's ran 1 3/4 LG headers. Why?

Here are the things we can and have controlled... best intake on market in the FAST 90 setup. 1 7/8 kooks should peak well. Good sized cam. Lots of cubes. Now, the remaining variable is the heads. Valve float yes, but it will probably just carry the power, not make more. I am a witness to that, I dyno'd 1 day ago to prove it.

10.5 Dave

iTrader: (5)

*Update* I decided to sell my LGM headers and bought a set of Kooks 1 7/8 with off road X pipe from Scoggins Dickey on Friday.UPS should have them here by Wed.

I'll put the stock rockers back on with the correct length pushrods and re dyno.I'm also installing a O2 bung to make tuning the car easier.

I'll offset most of the cost of the new headers buy selling the LGM's.If I don't get to where I want to be I'll probably do a head swap.

CHRISPY

Dave,

Let us know how things go. I bet the rockers will solve the big dip in power.

Good luck,

Chris

JS

iTrader: (4)

It'll pick up 20RW

Mike K.

what about some cutouts? for as cheap as they are and since you are replacing the exhaust anyways you may as well do it ya think? May as well pull out all the stops.

Tony Mamo @ AFR

iTrader: (13)

Actually, just to clarify, assuming valve float is in fact one of the culprits here (which seems likely), I do in fact believe you will see a gain in peak HP (assuming the stock lighter rockers do in fact provide better valve control)....what I was questioning and commenting on was the lower TQ figures and how at that RPM (around peak TQ) valve f loat would not have that much of an adverse effect. Basically, a bump in peak HP wouldn't surprise me, I'm just curious about the TQ which might not show a gain at all. Also, the move to the larger headers might hurt TQ a little more, while slightly enhancing peak power figures and obviously carrying the power stronger past peak. What would be interesting is the average power and TQ produced by both from say 4000-6800 RPM's.

Personally, I would like to see the tests done independently of one another (headers and rockers of course), because I'm still hanging my hat on the fact the headers aren't holding back this combination very much, and any significant gains seen will most likely be from better valve control.

Just my .02....

Tony M.

jaberwaki

subcribing

Rhino21149

[QUOTE=Roofer Dave]

The dyno graph shows the engine peaking at 6100 rpm and it nosedives.It only makes 320 rwhp at 6600.

I think the problem is the Patriot heads not being able to feed the engine up top.

What do you guys think?

I think it may be your exhaust:::::: consider.

Your engine is very similar to the one I had built by Charlie Hempfield Racing and put in my '02 ZO6:
C5R block, 427.6 c.i., Crower rotating assembly (overbalanced crank), CP pistons, Pat III heads, FAST 90 mm, etc. , etc.
However:
a. I had the heads additionally ported and polished by Justin Engineering, based on some article in GMHP that showed 540 HP (engine dyno) on a 346 with an extreme cam. I think this added maybe 10 HP is all.
b.I have 1 7/8 inch Kooks headers rather than 1 3/4,
c. super-size cats, 3" H pipe, and a GHL exhaust instead of stock exhaust.
d. only 10.25:1 compression ratio so I can put some boost on it . . .
With a Crower stage III catelog cam (somewhat milder than yours), N.A., it made 485 RWHP at 5800 RPM peak on a pretty accurate dyno. Power dropped rapidly so we didn't even test it above 6000.
I talked with Crower about these "disappointing" numbers and my desire for really good street manners, and they designed and custom ground a new cam that made 507RWHP@6100/514torque@4500, no real drop off to 6500 red line: still making 500+ at 6500.
I bought but never installed one of the radical cams from MTI which I have no doubt would have done better.
WHEN WE REMOVED THE CATS AND H-PIPE AND TESTED THE CAR WITH OPEN HEADERS IT GAINED 28 HP AND 30 LBS OF TORQUE; and the HP curve was still climibing at 6500 More important it gained something even right off of idle (a dead give away that the exhaust was too restrictive).
For what its worth you might consider that this exhaust is much freer than the one you have currently and yet still was holding this engine back.
((By the way, I ended up keeping the custom Crower cam in it just because . . . with a D1SC and only 4 lbs of boost it now has 565/550 RWHP/RWT@6000/4500, with more available if I put on a smaller pulley, and it idles and behaves very well in traffic.And I'm trying to find 2" headers and 3 1/4" H pipe.

DopeFedZ

iTrader: (34)

Forget about the dyno numbers just test it at the track. My 427 dynoed in the 450 range yet it was still good enough for 10.30 on motor.

10.5 Dave

iTrader: (5)

Trust me the car will see the track before the end of the season up here.

BaddMood

I heard you went 10.70's @ 129mph....not bad for a "weak" 422. I just want to know why everyone is so hung up on dyno numbers?? It's just a tuning tool, not a gauge

Greg Fell

iTrader: (9)

10.88, so almost 10.9. The 129 is not bad, but we had a good tailwind, and the DA was ~30.

I agree that it is a tuning tool. However, I do not think that you honestly can say that if the car made 520/500 (like most other 42x's, or even 40x's), that it would not be faster?

Pete K

Glad to hear you hit the 10's on the motor Greg.

One thing to keep in mind though, more peak power does not guarantee better times at the track. Average is what we're after. Peak numbers sell motors...the average number is what makes them fast.

Case in point, I was recently speaking with Roofer Dave on the phone and he indicated he had 2 friends with 422 motors built from another shop. Both made considerably more than his on the dyno. I think one made about 525rwhp and the other closer to 550rwhp (correct me if I'm wrong Dave). Not sure if they have been to the track yet, but Dave did say he dusts them pretty bad.

So what do the numbers really mean??...absolutely nothing. The dyno is just a tool as said by someone else earlier, a pretty big one actually. But hey, its great for bragging rights!



Pete

Greg Fell

iTrader: (9)

Thanks Pete! I agree that average power is what wins races. But again, if the hp AND tq is higher, there will be more average power. I am more concerned with my apparent lack of torque (459). Tq wins races, hp sells moties yata yata. I have the WinPep dyno viewer and thousands of dyno runsfrom my buddies shop. I've spent a lot of time looking at all variations of 'power', from very peaky bike motors to 500/500 Vipers to 900 rwhp pro stock cars. Pretty fun to do. While I'm not a professional mechanic, I am not a novice either and do think I can hold my own and I feel I 'get it' in regards to theory/principles of this stuff. I enjoy learning more than anything.

Also, were the cars w the 422's dave ran, in 'lightweight' zo6's, with favorable gear ratios/aerodynamics etc? Just to keep it apples to apples. If so, hot dog nice job Dave.

Pete K

I'm not sure of those details...Dave would have to chime in on that one.

Pete

10.5 Dave

iTrader: (5)

Pete K I don't know if you are confusing our many conversation but I want to point out to everyone I haven't raced ANYONE with the new engine.

When the car was stock I cannabilized every stock Z06 I raced.

I'm sure the two local guys with MTI 427 Z06's would have their way with me considering I'm 30-70 rwhp short of what they have.

10.5 Dave

iTrader: (5)

I put the car on the lift and started turning wrenches on it today and found out I have bigger problems than I thought.

When pulling the driver header I smelled coolant and broke out the flashlight to investigate.Coolant was dripping off the block below each head.

The cheap *** FelPro 1041 head gaskets ARE used are blown on both sides.The heads are coming off this weekend.When the heads are off I'm having them flowed to see what I really have.I doubt they will be up to par so they'll probably getting replaced.

Greg Fell

iTrader: (9)

Geez, what a deal. How many miles have you put on it since you've had it back?

LS7 time dave...

Phate

iTrader: (2)

Jeez Dave, are you really suprised...it is ARE/Autoworx after all.

10.5 Dave

iTrader: (5)

I'm not suprised or pissed at all guys.I knew going in with an ARE engine it's always a roll of the dice.I knew upfront there was a good possibilty I would be replacing their cylinder heads anyway.As long as the short is okay I'm not going to worry about it.

I'm going to do a project 2wd extended cab stepside for my 17 yr old son and the Patriot/ARE heads will be going on that engine.

Greg the new engine has 1,300 miles on it and I've been smelling coolant for a couple weeks now.