Dyno results 03 RS6 C5 GIAC chip tune 91 octane

[Audi-RS6]

Did a dyno after fixing my ICs

Car:
03 Audi RS6

Mods:
GIAC tuned
Billet DVs

Condition:
80 F outside temp

Boost:
15psi on start and 12psi to the end

True Results:
341.1 whp
387.1 wtq

Advertised:
378.2 whp
387.2 wtq

True...



Advertised...

[DHall1]

Where is the A/F graph?

Got it...the black one.

Well, my friend you have a problem. Your car is running way too lean and that is one of the reasons why your peak hp comes so late.

IMHO your peak tq point should be the richest portion of the a/f graph. In the range of 11.4:1 for a street car that is tuned. From there you can lean on it alittle say to 11.8:1.

A safer tune would have you 11.0:1 at peak tq then tapering to 11.5:1 at redline.

You better look into why the readings were so lean.

[Audi-RS6]

Are there ways to correct this tune?

[DHall1]

1. Call the dyno shop and ask what A/F sensor was being used. I would have confidence in the readings because if you look at the graph...as A/F came closer to 12.0:1 your h/p numbers actually rose.

2. You need to figure out who in the heck did this GIAC tune. Did you pay to have it done? PM me if you have questions.

3. Just a general check under the hood for missing or open vac/boost sources. But again, your boost number was good so there is little reason to think you have a leak. If you did have a boost leak you would be running too rich anyways.

4. Check your fuel filter and maybe have the fuel pressure tested. Again, if this were a concern the MIL indicator would have come on.

I would point the first finger to the GIAC and get some detailed Vag-Com readings done. Return the car back to stock and retest the car.

If these readings are true. You will blow this motor up. Period.

Are there ways to correct this tune?

[BCY4.2]

Something is wrong with the car/tune, standard cars made ~350whp and the A/F ratio is rather lean but the standard cars are tuned ~12.9 at WOT but with more timing/boost a richer A/F is needed for safety.

[peiserg]

here's my OCT dyno with before/after. I will try to also upload my boost/afr sheet.

My 6000 mile rs6 only put down 320 awhp on my first trip in. Had car checked at 3 audi shops, and they all said car was fine.



When i did a dyno with another rs6 right after me, our curves looked the same.. and he only put down 330 awhp.. i think it's just the heat and gas around here.

[DHall1]

There may be some variation in true A/F readings if your sticking a sensor up the tailpipe. The exhaust is going thru 2 cats before the sensor is picking up the A/F. Still it should be stable.

I have a wide band O2 sensor test kit and data logger. Next time I have a chance....I will check my car at the tailpipe.

[Audi-RS6]

amazing,

your curve looks almost same as mine, I guess very possible it should be like that.

here's my OCT dyno with before/after. I will try to also upload my boost/afr sheet.

My 6000 mile rs6 only put down 320 awhp on my first trip in. Had car checked at 3 audi shops, and they all said car was fine.



When i did a dyno with another rs6 right after me, our curves looked the same.. and he only put down 330 awhp.. i think it's just the heat and gas around here.

[peiserg]

I'll try to upload my APR software sheet..


the problem here was that the 91 chipped setup made LESS power than the 91 stock. and the 100 octane set wasn't that great either.

the "91 chipped" tune was on the dyno with 100 octane in the tank! so there's no room for arguement of bad gas....

the car just felt the same as before.... but it was actually down on power! I spent $1000 and a month chasing down issues before the APR guy here locally just said "Go back to stock.. i don't know what else to tell you"

[10SecS4]

Are we sure the black line is the wideband AF ratio? If so, that is nuts! On 91 octane, you want to be in the 11.0 to 11.5:1 range.

Assuming the black line is in fact your wideband AFR, you're running 13.3:1 at peak torque! I don't know how you haven't already melted something if that's an accurate reading.

RS6s are extremely sensitive to heat and if there isn't adequate cooling on the dyno, your power numbers will suffer. Different dynos will also give different readings, not to mention there are different correction factors and other variables which can affect the numbers.

Unless you're using the dyno with adequate cooling and using it to test mods before and after, it's pretty useless in my opinion. So, I don't put much faith in dyno numbers. This is why I like to do all of my testing and tuning out on the street. I keep as many variables constant as humanly possible, such as using the exact same stretch of road, starting RPM, direction of travel, etc. I also take coolant, oil and intake air temps into account from run to run.

IMO, a good way to gauge your horsepower would be to take your car to the dragstrip and look at the trap speeds. A stock and healthy RS6 running 91 octane at or near sea level should be able to trap 106-108 MPH. Tuned, it should be in the 110-112 range on average.
__________________
Marc aka 10SecS4



2003 Audi RS6
11.59 @ 118.63 | Video | Timeslip
Mods: No pre-cats & my own custom tuned ECU/TCU. That's it!

2000 Audi S4
10.73 @ 132.76 | Video | Timeslip
Mods: K04s + bolt-ons + weight reduction (bone stock motor!)

[DHall1]

Uhhh,

Pretty much what I said.

:cool2: 100% agree. Houston...we have some issues here.

Are we sure the black line is the wideband AF ratio? If so, that is nuts! On 91 octane, you want to be in the 11.0 to 11.5:1 range.

Assuming the black line is in fact your wideband AFR, you're running 13.3:1 at peak torque! I don't know how you haven't already melted something if that's an accurate reading.

[10SecS4]

Yep, but the only question is whether or not he's that lean out on the open road where cooling is far less of an issue.

With his AFRs that high, it should have definitely triggered EGT enrichment, in which case the ECM should have dumped fuel as a safety precaution. That's the way it would work with the stock tune or my tune; however, GIAC may have disabled this safety feature in their tune.

On 91 and 93 octane, I like to be a little richer than what I've seen from other tuners. It lets me run 2-3 degrees greater timing advance throughout most of the RPM range.

Uhhh,

Pretty much what I said.

:cool2: 100% agree. Houston...we have some issues here.

[DHall1]

I would like to get to the bottom of this GIAC business.

If the chip is crap. I would like to publish those facts here for the other members.

I would suggest GIAC to stand behind thier product and pitch in here.

Yep, but the only question is whether or not he's that lean out on the open road where cooling is far less of an issue.

With his AFRs that high, it should have definitely triggered EGT enrichment, in which case the ECM should have dumped fuel as a safety precaution. That's the way it would work with the stock tune or my tune; however, GIAC may have disabled this safety feature in their tune.

On 91 and 93 octane, I like to be a little richer than what I've seen from other tuners. It lets me run 2-3 degrees greater timing advance throughout most of the RPM range.

[chairman2300]

This is good, we should keep this going. Im a c hair away from a GIAC tune. I wont waste the money if this is a common issue with GIAC

[DHall1]

So far the Revo is on top for me. I like the ability to adjust some fuel and timing points and reflash to stock if needed.

10sec Marc is a second if I can corner him on the phone and see what hardware he is using to reflash. Customcode or what?

Giac is just too pricey and now with this problem revealed. They may go to the bottom.

This is good, we should keep this going. Im a c hair away from a GIAC tune. I wont waste the money if this is a common issue with GIAC

[Audi-RS6]

I wrote to GIAC, waiting to run my vagcom data this week:

" ...Our RS6 software uses a target lambda that is programmed at a safe level and adjusted by the primary wideband O2 sensors. If your RS6 is unable to achieve a proper air/fuel ratio, it is due to a hardware issue...
Please get me a log of blocks 003 and 031 in 3rd gear from 3,000 to 7,000 RPMs in vagcom as this will show me what the widebands are seeing pre-catalytic converter in the downpipes... "

I'll post results

[10SecS4]

That's an interesting response. I say interesting for a couple different reasons. First, the RS6 doesn't come with wideband oxygen sensors. They are narrowbands. Second, the oxygen sensors do absolutely nothing at wide open throttle.

I wrote to GIAC, waiting to run my vagcom data this week:

" ...Our RS6 software uses a target lambda that is programmed at a safe level and adjusted by the primary wideband O2 sensors. If your RS6 is unable to achieve a proper air/fuel ratio, it is due to a hardware issue...
Please get me a log of blocks 003 and 031 in 3rd gear from 3,000 to 7,000 RPMs in vagcom as this will show me what the widebands are seeing pre-catalytic converter in the downpipes... "

I'll post results

[DHall1]

In a prior life....I tuned ECU's.

What this guy just said is a crock of shit. Sorry to be blunt.

Once you go WOT in all the other ECUs I have worked with.....the ECU moves into "open loop". For those that know...that means the 02 sensors have nothing to do with the A/F ratios at that point.

Now, for tuning sake. You do need wide band 02 sensor readings to taylor your fuel curve and rewrite the fuel tables. But the stock 02 sensors are doing nothing in open loop.

Sorry, but unless I am missing something this guy is an idiot.

That said, I would like to see the readings of the stock 02 sensors at the RPM levels and test he recommended. It will show a snapshot of what is happening. Not exact but close.

Edit: Marc...you beat me to the punch. Damn it! LOL, I take too long to write my responses.

I wrote to GIAC, waiting to run my vagcom data this week:

" ...Our RS6 software uses a target lambda that is programmed at a safe level and adjusted by the primary wideband O2 sensors. If your RS6 is unable to achieve a proper air/fuel ratio, it is due to a hardware issue...
Please get me a log of blocks 003 and 031 in 3rd gear from 3,000 to 7,000 RPMs in vagcom as this will show me what the widebands are seeing pre-catalytic converter in the downpipes... "

I'll post results