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Discussion Starter · #1 ·
Well I am a little disappoined in the cars dyno result tonight - 3 pulls, 347,350 and 351 corrected RWHP. That seems about ten light for an 02 ZO6 to me. Check ABS and Check Active Handling lights came on (ACS switched off for dyno) - seems the Vette doesn't like the dyno - but that shouldn't affect results.

We did run data acquisition and this car is running RICH - 11.4-12.0 on the high end. The roller rockers, push rods, HallTech T-1, Vinci 170 Stat and fan controller go in tomorrow. The Halltech should lean it out a bit - otherwise I assume a MAF translator of some kind is in order - what is the view here please?

Thanks,

Les
 

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11.4 to 12.0 A/F on a bone stock Z? Why do they run so rich?

How many mile on her? They seem to loosen up some after about 2000 miles.

Those numbers aren't that bad, and you have to realize that each dyno has a +/- range from any other dyno. But seeing the A/F, its probably down a few HP due to the richness.
 

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Discussion Starter · #3 ·
I haven't seen where others are running this rich. 351 isn't horrible, if you divide by the .85 drivetrain conversion factor that says it is making 412 at the crank. I thought others here were getting a bit more is all, and that rich condition will rob power. The car has 2300 miles BTW. YOu point on variance from dyno to dyno is a good one.

Les

ZeeOhSix said:
11.4 to 12.0 A/F on a bone stock Z? Why do they run so rich?

How many mile on her? They seem to loosen up some after about 2000 miles.

Those numbers aren't that bad, and you have to realize that each dyno has a +/- range from any other dyno. But seeing the A/F, its probably down a few HP due to the richness.
 

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ZO6/Les said:
I haven't seen where others are running this rich. 351 isn't horrible, if you divide by the .85 drivetrain conversion factor that says it is making 412 at the crank. I thought others here were getting a bit more is all, and that rich condition will rob power. The car has 2300 miles BTW. YOu point on variance from dyno to dyno is a good one.

Les

Les,

I have a LOT of experience with Dynojets...and have tested on several different ones over the years. They can have a slight error factor b/w them.

I've only dyno'd my Z once...with 660 miles. 350rwhp, bone stock. Mine was also very rich. Down to 10.8:1 on the top-end.

There's 7-8rwhp in just leaning it out to the mid-12:1 range, IMHO. Then there's more once the engine gets broken in.

I have dyno time scheduled for Friday. I've installed the Vortex Rammer intake box and duct as well as a 178^ t-stat and fan controller, and throttle body bypass. The latter two items will only make the power more consistent, probably will not increase it. On the dyno, I really don't think the Rammer box will show much (maybe 5-6rwhp), but on the street with the ram-air effect it does make a difference.

Then its time for headers and nitrous. :)

I don't think your numbers are out of line for a car with so few miles on it.
 

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Rich

Guy's the #'s you are showing aren't bad, they could be better, but You WANT to be in the 12.1-12.6 range WOT.............
So, if anything you need to go UP not down......
And 350 for a stock '02 is about right, with 355/360 being on the HIGH side of normal.............Bone Stock:)
 

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ZO6/Les said:
...3 pulls, 347,350 and 351 corrected RWHP. That seems about ten light for an 02 ZO6 to me....
Hey Les, what was the sequence of the pulls. Did you list them in order?

Ranger
 

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Discussion Starter · #7 ·
Ranger,

Yes they were in sequence. First run the car was a bit cold, last two fully warm.

Les

Ranger said:


Hey Les, what was the sequence of the pulls. Did you list them in order?

Ranger
 

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My opinion is that the DynoJet is very repeatable. It's the correction factor that is not. Get yourself a weather station that calculates CF.
 

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Les,

Dynoed my bone stock a couple of weeks ago at SpeedWorks. With 2600 miles it pulled 356.3 RWHP, and also was running on the rich side. There were at least four other new Z06's there, bone stock and the lowest one pulled 347, but only had 600 miles. All of them ran rich!!!!! Your #'s sound good to me. I am not sure how to correct the rich issue, but the technicians I spoke to said that a K&N and a better filter box cover would cure the problem. My FRC ran what they called a "perfect" fuel curve, and is equipped with a ProDyno Twin Cone cold air kit. Remember that your computer is "ADAPTIVE" and will also pick up power as it learns how YOU drive. These cars are made to run!

Joe :D :D :D :D
 

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gees, I think those dyno numbers look great! I'd take those everyday of the week and twice on Sunday for a bonestock car.

I'm dynoing mine 3/2/02. I bet it will have around 1000 miles by then. And I agree with slyck, these cars are MADE to RUN!! They ain't real happy campers unless your revving over 4500 :D
 

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Discussion Starter · #11 ·
After reading through old posts I have concluded that my dyno numbers are pretty much normal - and again when adjusted for power train loss = 412 at the crank so I am not complaining. I am surprised that they run this rich, if the T-1 doesn't lean it out enough I will consider other options. I would like to see no richer than 12.5 on the top end. With some tweaking and the T1 I believe you can easily get another 15-20 RWHP from these cars - I will have some further results tomorrow and will publish, good, bad or ugly :)

Les

PS: Trust me, I agree these cars were made to R U N.

C4C5 Specialist - what is your view on the A/F ratio on these monsters??
 

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I remember reading either on this forum or over on the CFivevette forum where the Zs were all running rich at WOT. Then I read somewhere else where the 02s were running lean at WOT, and larger injectors were being called for.
So what's the real scoop, are the factory stock engines running rich or lean at WOT? I could have my facts confused too, so be gentle on the floggings.
And your right about the LS6 coming alive as the RPMs climb, it's almost a different animal after 5000.
C4C5, does the ECM learn and compensate for the higher RPM F/A ratios if one ventures into that territory often enough?
Stan :cool: :cool:
 

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ZO6LS6 said:
12.5 seems to be the general consensus for optimum power........at least this is what I have been seeing.....:)
You know, I wonder if the RWHP/FWHP numbers aren't all smoke and mirrors or bragging rights? The single thing I noticed when we had the dyno day at SpeedWorks with 4 bone stock Z06's is that the Torque numbers were more consistent between the cars-that is the pulling power, isn't it? What surprised me was that my '99 FRC was as close to my Z06 as it was. The FRC pulled 341.5 Q while the Z06 pulled 345.5 Q.

Joe :D :lol: :lol: :D
 

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slyck14 said:


You know, I wonder if the RWHP/FWHP numbers aren't all smoke and mirrors or bragging rights? The single thing I noticed when we had the dyno day at SpeedWorks with 4 bone stock Z06's is that the Torque numbers were more consistent between the cars-that is the pulling power, isn't it? What surprised me was that my '99 FRC was as close to my Z06 as it was. The FRC pulled 341.5 Q while the Z06 pulled 345.5 Q.

Joe :D :lol: :lol: :D
HP is a function of what your TQ curve looks like, though. I bet your FRC makes peak TQ at a lower rpm, and doesn't carry as flat of a curve as the rpms rise...which is why the Z06 makes more power on the top end.

My Lightning truck, for example, makes 444rwtq...but at 3500rpm...so by the time the thing revs to the point it makes peak HP (5200rpm)...the TQ curve has fallen off significantly, and HP never climbs very high. BTW, this is not a poor power curve for a 4500lb truck. :)
 
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