Pleased w/ dyno results...

[Paul Workman]

I went to the Vette Fun Fest at Effingham yesterday - first time for everything. It was impressive. Was invited to caravan down w/ a local Vette club - mostly C5s, but a few C6s and a C6 Z06 as well...Oh...and one gorgeous(!) ZR-1!! It rained on the way down, and on the way back. But, at least for the daylight hours on Saturday, it was perfect. But, I digress...

I have wanted to baseline my Z before beginning my winter projects. Far as I know, it has new injectors and a Borla catback and stock chip. So, I was a little surprised at the better than expected runs.

Not surprising, the pulls got stronger with each successive run, ending at 339.0 hp/336.8tq - the ECM was "learning". Extrapolating by 15% for a manual transmission, etc, the fwhp would be in the "hood" of 399 for the top pull - not a bad starting place.

What is a concern is the air/fuel trace confirmed what I saw on the plugs a few months ago: Lean. I'll want to check my fuel pressure and perhaps inspect/change the sock and FF too. That said, I see the air/fuel ratio graph flattens out above 5k, which would not be the case if leaning out was purely due to pressure drop across a dirty filter. It appears (to me) the catback was probably installed w/o subsequent (necessary) retuning. What say U?

(Note: The "throttle man" did not know my tac reads high, as so he shut it down when it read 7k. It appears he captured the peak hp, but I would like to have seen the rest of the graph too. And, b/c I pulled the plugs some time ago, after a few 7k runs and the plugs looked "lean", I had them run the air/fuel track as well. (See below))

Although it was was human error to cut it off just above 6k, I was very pleased with the torque curve's flateness. Gotta love these LT5s!

Penny for your thoughts!

P.

[Paul Workman]

Another Registry member, Ken, joined me at the dyno tent. Ken has a chip in his, and we thought it would be fun to compare results, so he ran off to get his car - a 90 ZR-1. (Maybe he'll post the results later?)

In the mean time, there was this C5 driver, apparently watching my "C4's" dyno results closely, and then his car was next. The stock(?) C5 pulled 300 rwhp. I don't know what he expected from a stock 03 C5, but 300 rwhp seems about right, no? Maybe he thought it should have done better, or perhaps he thought he was watching a standard C4 when he saw the results - I dunno. In any case, he was pizzed! I guess the 300 hp reading ruined his day, in spite of the fact that it would be in the area of 352 net fwhp - about right for a stock LS1, methinks.

P.

[Polo-1]

your a/f is out of wack. it's backwards of mine, and most others.

[Toyvet1]

Paul, Ill post my dyno sheet later when I have the time.The Z ran 334 hp/ 330 tq. A solid 300+ tq from 2300 to 6900. Air fuel was lean until 3300 then solid until 7000. Im running a chip from Mark H and drivabilty is where the chip shines. Paul and my power curves were pretty much carbon copy. Dyno man was happy to overlay our runs on the samer sheet. Ill post a copy of it later also.

FYI on the way backI hooked up with a group of guys around half way home and was running 85+ with some burst above for about a hour until they exited. Great thing is I was getting 21.5 mpg at 75 before and milage went up to 22.4 after letting the car run. Oh I was running for the fun of it with the power key off and had no problem keeping up with the C5 and C6s. The fun started when power was turned on!

[Paul Workman]

Um yeah...My plugs would agree to the point of me taking it easy until I can get a chip from Mark (or ?). On closer look at the original sheet (easier to interpret), air/fuel seems to level off at 14.0. In addition, there are the idle and 230º first fan switch issues that I look forward to a new chip to be able to address as well.

Thanks for the input.

P.

P.

[Aurora40]

Originally Posted by Paul Workman

Not surprising, the pulls got stronger with each successive run, ending at 339.0 hp/336.8tq - the ECM was "learning".

Probably more likely was you were getting less knock retard with each successive run, as all the oil and carbon and whatnot burned up. I don't believe much learning goes on at WOT.

You sure that A/F ratio is right? It seems dangerously lean near the end.

[Paul Workman]

Originally Posted by Aurora40

Probably more likely was you were getting less knock retard with each successive run, as all the oil and carbon and whatnot burned up. I don't believe much learning goes on at WOT.

You sure that A/F ratio is right? It seems dangerously lean near the end.

From the perspective of zero dyno data to begin with, I learned a good bit about WOT AND my air/fuel mix. Do I know it is right? I suspected it was running leaner than ideal from reading plugs. So, the lean a/f graph came as reinforcement of what I was seeing on the plugs. So, I felt I learned a lot...and was happy with most of the numbers (such as they were).

Anywayz...After some a P&P of the top end and bolting on the SW headers and a Marc H tune, the Z should be ready to elbow it's way to the bar with most contemporaries, doancha think? Funds allowing, I would like to do a 411 rear gear too. That should brighten up the 6th gear a bit, especially at freeway traffic speeds.

P.

[Toyvet1]

Upper chart is my stock 90 with a chip from Mark H. The stuttering of the line we were told is from electronic interferance and shouldnt worry about it. It has something to do with the inductive pickup leads.

Below is a overlay of my Pauls car and mine. I was thinking I might get a little more power from the chip. But the chip shows it worth on driveabilty and idle issues. My casr has the blue power curve and Pauls is red. A/F is interesting chart.

Originally Posted by Paul Workman

Not surprising, the pulls got stronger with each successive run, ending at 339.0 hp/336.8tq - the ECM was "learning".

There is no learning at WOT. It reads from a set table, and only changes when it picks up knock, or there is a SES light that comes on. Typically you will see the second pull as the best, as it has blown out all the crap from the first pull, and the third pull usually goes down due to heat soak.

[Paul Workman]

Originally Posted by Jeffvette

There is no learning at WOT. It reads from a set table, and only changes when it picks up knock, or there is a SES light that comes on.

Now that you mention it, I think I knew that. CRS disease, I recon!!

I appreciate your taking the time to comment, Jeff.

P.