cypher85

Greetings,

I just helped my friend install a H/C/I/E in his 04 z06, need some opinions on this build, we think it should be making more power with the current list of mods.. So does the tuner. Dyno sheet attached. Numbers are 439whp/ 393wtq, stock bottom end with 70k miles.

List of mods:
-Vararam with PD
-STOCK 85 maf
-Ported ls2 throttle body
-Fast 102 with velocity ring
-FIC Bosch 3 inj 42lbs at stock pressure
-Ls2 fuel rail
-Dart 225 heads with psi springs: 120lbs seat-1.800, 360lbs-1.175, coil bind 1.100, .625 max lift
-STOCK rockers currently, Harland sharps will go on soon
-Ls7 lifters and comp hi-tech pushrods
-Mike Jones cam: 231/236 @.050, .612/.600 lift
-Melrose exhaust: 1 3/4 headers, no cat, x-pipe, corsa xtreme axle-back

Mike Norris did the tune on a 248x dynojet, power delivery is smooth and strong. I am curious by the power curve flatlining for 700 rpm, Mike Norris thinks the numbers are low and not sure why. I got with Mike Jones and he looked at it and doesn't see signs of valve float.

What do you guys think? No leaks, engine operates quietly and smoothly and no codes.



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cypher85

Link to dyno run, with the ti axle-back, we put the corsa on after.

01badvette

Your power levels and everything seem pretty inline with the Mods. I'm not sure what your expecting to see but you have a medium size cam and decent flowing cylinder heads 440 rwhp seems about right, torque is a little low but that could be the cam characteristics or a combinations of the intake/cam and exhaust.

vettenuts

To be honest, the original as cast Dart heads were about equivalent to marginally better than the 243 heads you removed. However, given the 243's had the lightweight valves, IMO I would have kept them. I think your power is in line with expectations. Also, if you are running the Dart's with stock rockers you will have some serious valve guide wear going forward.

cypher85

We were expecting about 20 more. Like I said it makes good smooth power. We will be putting those Harland sharps for that reason vettenuts. Thanks guys for the input, he is happy with the car.

FASTFATBOY

I'd say the car is 20 rwhp down also. I made that power with 11 to 1 and a similar cam with a 111+1 LSA. Stock heads and intake, ported stock throttle body.

Did anyone do the math on compression?

Was the MAF clean when it was tuned?

Is there a baffle loose in the stock muffler?

Was the air filter clean? They get dirty QUICK with a VR

That curve on the sheet is quite ugly, jus sayin.

cypher85

I did the math on the compression and it cam out to 10.9:1. Maf was clean for the tune. The stock muffler has already been changed to the corsa xtreme. The vararam is new and with filter. We are taking the car back to Norris on Monday for an adjustment tune, this thread was intended to bring up any possible areas to look at before then. We can take the MAF off again to be sure it is clean. Roller rockers will be fitted for the adjustment also.

Supercharged111

My thought was that the Fast 102 is a little big for a 346 and vettenuts confirmed my suspicion that the heads were meh.

FASTFATBOY

Can you turn the key on and confirm 100% throttle blade opening while the MAF is off?


Clean the MAF with Q-Tips and alcohol, that spray stuff won't get it done.

Is this a SBE car?

How far is the piston out of the hole?

Full flat top piston?

Did you actually CC the head or take their word for it(before and after if they were milled)?

What gasket compressed thickness?

cypher85

I am not currently with the car to check the throttle blades. Q-tips and alcohol is how we clean them. It is a sbe car, mileage in first post. Piston are .005 out of the hole, compressed thickness is .051, chambers are advertised 62, did not cc heads. Full flat tops.

Heads brand new when we put them on, they were not milled.

FASTFATBOY

Because you didn't CC the head, you have no idea what compression you really have. Did you check deck height, or did you use the "commonly known" number?

My LS6 243's were 65 CC's AFTER they were milled for a clean up and the valve job done. So I could guess they were 66 ish cc prior.

My piston was 8 out of the hole(block was square decked), Mahle piston had 4cc reliefs, .051 gasket. I had to mill to 59CC to get 10.95 to 1.

I would not surprise me if you were down on compression. How much wot timing does it have?

What length push rod is in it? The LS7 has a taller cup in it over the stock lifter if memory serves, so it'll take a shorter pushrod.

What is the cams LSA?

Paul 75 L82

Forget the numbers, are you happy with the performance of the car?

cypher85

I checked everything but the head c.c., checked pushrods length before ordering new pushrods, checked deck height.

Cam is 114 LSA, pistons do not have valve reliefs. Dart claims this head is cast at 62cc, my AFRs in my vette were much smaller than advertised. I do not think we are down on compression.

I do not have timing information, Mike Norris did the tuning and we have not datalogged the car yet.

cypher85

Yes he is happy with the car, just looking to see if there is anything glaring to point out that may help.

alextz

Im guessing that 85mm MAF is bottle necking you.

FASTFATBOY

Nope

cv67

Mike get that thing datalogged make sure something funky isnt going on
If all looks well get a mph at the track as you said

Nothing wrong with Dart heads they just approach things a little differently; you know Mike Jones grinds one hell of a good cam

Go from there...see how your C4 stacks up against it.

cypher85

Sounds good Ron, since the parts that are on the car are going to stay.. we will see if there is anything that needs attention in the coming weeks. Today my buddy mentioned it started running rich for some reason. Hopefully Mike can button down the tune for us this week.

Then we will datalog and see how it does at the track. One day I will get back my intake and will see how it does against the Z. I bested him when his car was stock, so we will see if the older brother c4 can keep the same with a bigger cam and some intake and head work! Thanks for the advice.

cv67

make sure you have perfect seal with your headers