Spent

iTrader: (1)

Daniel brought us his 01 Corvette (5.7L/Automatic) for a Diablo Sport Tune. His setup consisted of basic bolt on's. Also, the transmission parameters were tweaked for faster shifting and slightly higher shift points at the customers request. For the record, the same end results can be had regardless of whether it's Diablo Sport, SCT, HP Tuners or EFI Live..

Mods:
SLP Long Tube Headers
Corse Exhaust
MSD Coils
K&N Air Filter
Tuned on Diablo Sport








DynoJet Chassis Dyno Model 224x
The blue line is on the stock ECU (untuned). The Red line is the final run (tuned).

Spent

iTrader: (1)

Here's the vid.

http://s672.photobucket.com/albums/v...Tune340whp.mp4

Here's the chart at a smoothing of 2.

SAPS

With similar mods, my car put down 340 on a 224x.

A4's a pretty "granny" in factory form!

KONG

iTrader: (4)

Dang!!

Brice

Tuning LT Headers with a predator is ... retarded.

What about the knock ? what about the MAF and VE calibration ?
Tuning is not WOT tuning only.

The AFR is over 13 ... that's leeeeeean, I can feel the knock retard between 5200 et 5700 rpm.

For the record ... just buy efilive or hptuners and get a real tune. Are you hating your car ?

P.S get a wideband too ...

Brice

oh wait ... http://www.tdcauto.com/tuning.html

you're a professionnal tuner ... a professionnal predator tuner ?

thunderstruck507

iTrader: (18)

graph doesn't look very smooth around 5500

seems a bit lean too

MauriSSio

is 13.2 really THAT leeeeeeean? i havent seen anybody melt a piston at that afr level, im just wondering if its really that bad.

thunderstruck507

iTrader: (18)

mine is at 13.2 as well but the hp graph and a/f are smooth...his a/f looks leaner than 13.2 in all the waves, seems to be getting as lean as 13.5 and judging by the hp dip I don't think this particular car likes it much

MonmouthCtyLS7

iTrader: (6)

Hp definately seems low, especially for being dyno tuned

MauriSSio

it does get as lean as 13.5 at lower rpms (3500) but the graph looks smooth in that section and it does dip at the higher rpm @ 13.2-13.3 but then goes back up before it richens up a bit. maybe the dip is caused by something else?

thunderstruck507

iTrader: (18)

true and I don't claim to be any kind of expert...but I'm just saying if that were my car, I wouldn't be happy with the way things look and would like to see a smoother a/f line if nothing else

and if I paid the price listed on that website I would be down right pissed with the results if the car was meant to leave the shop that way

Brice

Try to road race @ 13.5 ... and have a look to your piston #7 ...

And don't trust the wideband in your muffler ...

MauriSSio

this guys thread is just a couple down from the one we're reading and he looks like he has his AF in the 13.2 area at peak hp and nobody gave him crap for it.

https://ls1tech.com/forums/dynamomet...c-install.html

from my understanding, a smooth AF line doesnt necesarily amount to much. At peak tq, afr's in the 13's generally see higher numbers, and sometimes at peak hp as well. Also it depends on how the car is driven, if it sees a lot of TIME at WOT (1/4mile does not count as a lot of time) then yes high AFR's will probably generate too much heat.

MauriSSio

heres a quote from a lil article ive read online reguarding AFR's

"Regardless of the actual ideal air/fuel ratio number, almost everyone wishes to see a nice, flat air/fuel graph. This means that the ratio stays constant throughout the rpm range. A perfectly flat air/fuel graph is certainly not necessary for optimum engine performance or safety, but it is a nice thing to show off when tuning a vehicle. The smoother the air/fuel curve, the better the drivability will be and the smoother the power output will be. All good tuners realize that a little variation with the graph is perfectly acceptable, especially when one considers the factors involved. One must consider the accuracy of the oxygen sensor, where it is placed in the exhaust stream, the velocity of the exhaust stream at different points in the rpm band, the tools that the tuner has at his disposal to make changes, etc. Another important factor is that most air/fuel ratios are measured via a tailpipe sniffer. This method has proven to be an excellent way of measuring the ratio, but it is not perfect at low rpm. At low rpm, an engine may not be producing enough gas to displace all of the atmospheric air in the tailpipe, and this will produce a false lean reading because of the extra oxygen - as one can see in this chart. This phenomenon is going to be more pronounced in small-bore engines with large diameter exhaust piping. Two important things must be considered when one is tuning with a tailpipe sniffer because of this phenomenon. One, a flat line across the entire rpm band will mean that the actual air/fuel ratio is too rich at low rpm. Two, a real-world driver is almost never at wide-open-throttle at such a low rpm, so the air/fuel curve at that point is something that the driver will never see. One can also see from the chart that the catalytic converter has no significant effect on the air/fuel ratio in this particular vehicle.



The flatness of the air/fuel graph when one is done tuning is mainly going to depend not on the competency of the tuner but on the type of fuel management system being used and its resolution, and the patience of the customer and/or his willingness to pay for dyno time. One must also ask - is a perfectly flat air/fuel curve best? Many assume that a flat line at 12:1 or 13:1 "across the board" is best, but why is that? How could it be possible that the exact same air/fuel ratio be optimum for every rpm and load? This idea has been largely ignored in automotive enthusiast circles, as "good" tuners with adequate engine management equipment produce air/fuel curves that are flat "across the board" at the desired ratio. Thankfully, this notion has been challenged recently, and experienced racers and tuners have begun to realize that air/fuel curves should not necessarily be flat. Turbos can spool up faster if the ratio is a little lean during that time, and rich ratios are more needed in the higher rpm range where more heat is being produced. Keep in mind that wideband oxygen sensors have only been in widespread use since the late '90's, and chassis dyno testing has only become truly popular in recent years. All of us are still learning. Few people have been able to perform true scientific experiments, and therefore few people truly have the knowledge to make blanket statements concerning what is best for a particular vehicle or group of vehicles."

Brice

The dips came from knock retard ... the pcm substract timing...
That's blind tuning ... PE table rapping ...

nysbadmk8

Doesnt look good from here.

MauriSSio

excellent point. we have to find out how this guy spends his time at WOT.

but also, that 13.5 is only at th beginning of the pull.

Mike@Diablosport

iTrader: (2)

Nice gains, thanks for sharing the results!

Mike@Diablosport

iTrader: (2)

A little more research on your end would likely have uncovered the fact that we offer our CMR tuning software, which is a full tuning suite allowing for full access to calibration data.

Looks like some pretty good gains to me...