Divertor valves failing?

[LaserSVT]

So I finally had a chance to take my RS6 to a drag strip and see what it could do. What a let down. Car ran a 13.0X every time at 106.X MPH. I was cutting a 1.9 second 60' and launching at apx 5psi but the car would only peak at 9-10.2 PSI for the entire run. Checked all the hoses and vac lines then gave up and went home. On the way home we played a little (I was with a pack of Cobras and Machs) and I noticed at half throttle car had no issue pushing 18+ psi and holding it.
Car has older Milltek DVs on it, could they just not be holding at WOT?

I dont have a VAGCOM and wasnt planning on getting one since I am selling the car so I cant really check commanded vs actual BUT several months ago it could hit 18 PSI at WOT. And yes, I reflashed the computer and did the sneaky reset to no avail.

I should also point out that air temps were 95+ and my intake temps were at 188 in the lanes and didnt drop much during the run, maybe 20*. I heard someone say the DA was 3200 but I didnt check. Humidity was through the roof.

[nubcake]

Impossible to tell for sure without logs: whether it's requesting the boost and not getting it or cutting the load for some reason. Need to know the actual N75 duty cycle and requested boost. My guess is that hardware is fine and something's wrong with your tune if it boosts fine at half throttle and falls on its face at WOT.

EDIT: 188f is pretty high indeed, ECU will decrease boost request by ~24% at that temp with stock settings. Other factor might be too high engine temp, it will limit boost as well.

[lswing]

Heat soak. It's not going to allow boost if intake air temps are off the charts. Running on the open road you're getting a ton more cooling.

My car usually felt a bit sluggish in the Texas heat compared to a rocket on a cool crisp Oregon day.

[B727]

Not diverters. If failed, doesn't matter if full throttle or half, they won't hold (pressure is pressure).

Motronic adjusts boost based IAT (among other things) so I imagine high temps is the root of it. Take proper logs and head over to nefmoto.com, and those guys can tell you exactly what's going on.

[LaserSVT]

Yeah did a couple runs this morning since it seems everyone wants to call me at 7 am on my birthday and with 102* temps the car was seeing 17.1 psi which is normal for a 90* day.

Never realized just how bad heat soak was in these things. I really have only raced it during 40-50* days and the car was as happy as can be.

[makaveli42]

Man I think my car is a beast....by the track always seems to tell me different! It's a 45min stop and go highway traffic ride to the track so I know I lose boost due to the heat soak and engine temps. With the Daz TCU....do you run in drive or sport mode? I always do normal drive because that's what I was in when Daz tuned me. Just curious.

[Aronis]

Laser, do you have a boost gauge? You said you don't have VAGCOM so was wondering where you were getting the boost values.

I have my original diverter valves, I asked about replacing them but my mechanic said there is no reason to change them. The fancy aluminum DV's are eye candy....LOL......considering I was buying a lot of other stuff the cost of the DV was a drop in the bucket so if he thought there was any reason to do it he would have told me to get them.

I drove my RS hard yesterday and it did not disappoint!

Mike

[LaserSVT]

Car ran better in D than S. Allowed for more boost off the line and shifted at a higher RPM.

For boost I have a PLX OBDII gauge system with a boost module.

[Aronis]

Oh, cool....

[BradP]

Heat soak here running road courses as well...obviously plenty of air flow. Installed intercooler sprayers to spray water on the outside of the coolers when she starts getting cranky (loss of power and unpredictable downshifts into corners). We typically only see low 90 degrees here, but it makes a world of difference. $65-70. Also used them running a long autocross last week in 95 degree heat, windows up, and AC on. Squirted while in line for the next run. She stayed predictable there too keeping the crowd and I super entertained;)

[DHall1]

Can you post details on your sprayer system.

Pics too


Heat soak here running road courses as well...obviously plenty of air flow. Installed intercooler sprayers to spray water on the outside of the coolers when she starts getting cranky (loss of power and unpredictable downshifts into corners). We typically only see low 90 degrees here, but it makes a world of difference. $65-70. Also used them running a long autocross last week in 95 degree heat, windows up, and AC on. Squirted while in line for the next run. She stayed predictable there too keeping the crowd and I super entertained;)

[BradP]

I hadn’t taken pictures of this one. So, I tried to get a couple last night. Of course exposing myself to a couple of the few things I’ve done without split loom and heat shrink. Yes, Audi harnesses drive me nuts.

It’s a CryO2 kit. Looks like I paid $76 shipped from Jeg’sthrough EBay.

Button next to the left hand shoved into the dash. Actually a nice fit and right next to the fuse box.
<o:p> 17525I bought an extra fused tap to wire it. If I recall, I grounded the thing using a crimped ring stacked on top of a bunch of others on the fire wall.
<o:p> 17527
Losing the air box gave me enough room for there reservoir. A couple pieces of bar stock are welded and bolted where the upper control arm bracket is bolted. I ran short on hose, and bought some stuff at Home Depot. Note to self, put that crap in the bumper. It can’t take the heat! So, there’s a pile of heat shrink tacking that crap on the pumpJ It only leaks a bit,and it’s only the connection to the pump that gets hot. The rest is protected with split loom.
<o:p> 17526The sprayers themselves are just above where my fogs used to be. They are screwed into the air scoop for the intercoolers. Tried toget a pic…no luck.

The cap on the reservoir has melted a bit, but still snaps on there fine. I try to keep some water in there at the track to soak up some heat whether I'm using it or not.

I guess my biggest problem is forgetting to use it when I’m passing 911’s J Sometimes there’s just no luv for the Audi.</o</o</o

[lswing]

Nice, I almost did the same a few years back. Now you just need to do it correctly and spray water meth INSIDE the IC's:hey:...actually, both would be a sweet combo.

[lswing]

I dont have a VAGCOM and wasnt planning on getting one since I am selling the car so I cant really check commanded vs actual BUT several months ago it could hit 18 PSI at WOT.

So....how much for the stereo?

[LaserSVT]

Stereo was left in the car for the new owner. Took her out for a ride today to give her some exercise and forgot how much I love this car and stereo. Gonna miss it. :(