Fuel and Tunes, please help

B6 A4
#1

Since my 3.0 was tuned it doesn’t seem to like 91 chevron anymore. Thats all I’ve ever used but now its definitly not good enough. Its night/day when I run a higher octane. I know nothing about fuel and if its okay to mix them? The only fuel available to me that is not 91 is from VP Racing, They have a 93 which I’m not sure if that is their race gas blend or what but its $6.97 a gallon and felt great in my car when I first tried it with a 5-1 ratio of 93 and their streetblaze 100, which is the other fuel they offer. I couldn’t find any information on their 93 from their web site, but they did list info for their 100 and here are the specs on that…

SPECIFICATION SHEET FOR VP100
(aka StreetBlaze 100)

(Typical Values) Specific Gravity: .75 @ 60°F

Oxygenated: Yes

Color: Orange

Motor Octane: 96

R+M/2: 100

Oxidation Stability (min.) 1440+

Distillation:
10% evap @ 148.0°F

50% evap @ 210.0°F

90% evap @ 216.0°F

E.P. @ 238.0°F

Production: Elmendorf, Texas USA

Availability: Sealed Drums

Rev: 03/09

     I'm a little confused about the 2 octane numbers of it says M+R/2 is 100 but then it says the octane is 96? That gas cost about 9$ a gallon. It made me curious if I could mix the 100 and some Chevron 91 at a 5-1 Ratio would only cost me about 20$ more than a normal fill up at Chevron with premium and come out with a close to 93 octane? for a little less money than filling up with 93 would save about 20$+ each fill up, no idea if mixing is cool or what. Any and all information on this topic would be much appreciated as I have no experience with this. For me to fill up with the 93 thats 85$ a tank. Chevron 91 on my last fill up was 4.15 a gallon. which cost me about 50$ to fill up. Or if for some reason the blend of 5-1 ratio of  91 and 100 would work that would cost about 60$ a tank.
#2

Why don’t you ask JHM?

#3
#4

You can alwsys mix fuels you just need to know what your mixing you cant mix e85 or that will really mess things up. On the jhm tune I think they say 91 is good till 94 or 95 octane amd 93 is good till 98…

Are we talking about California 91 or east coasr 91

#5

Just don’t mix 91 with 89 or less. It might be fine for a few hours but then it will start misfiring, After you turn the engine off you under big risk to stuck there forever. I filled my tank once with 89 and drove for two hours then,stuck on the parking lot trying to start my car. I only fill 91 Shell or 94 octane from PetroCanada. Going above 94 might be not a good idea too

#6

Im thinking if you have a jhm 93 tune 94 and up is still good if you have a 91tune and put in 94 you can get a nice bump still

#7

We are talking about 91 in Nevada from Chevron, I’m not sure if Supreme from Chevron in California is 91 or not. JHM said I have the 91 tune. Right now my tank has a 5-1 Ratio of Chevron 91 and the VP Racing 100. After testing out the VP racing with a 5gal-1gal Ratio of their 93 and 100 I went and filled up with Chevron 91 and it started running like shit. And so I let it run through most of the tank hoping it would get better, so I filled up again with Chevron 91 again thinking I had bad gas or something was wrong from mixing and still nothing changed i so I went over to VP and added 2 gal of 100 to go with the 10 gal of Chevron 91 I had put in, and instantly my car ran smooth again. Well, you get what you pay for so maybe their 7$ and 9$ a gal gas is just really bad ass and makes the Chevron seem like shit.

#8

Going from good 94+ fuel back to 91 will make the car feel way way slower…when you switch back to 91 clear your ecu memory codee. I had to do that when I changed gas. It helps the computer relearn… your not going to make the 91 feel like the mucb better fuel…its still helpful

#9

Sounds like the 91 may not really be 91. Have you tried other gas stations? Anyone else offer 91 or 93 around you?

#10

I always fill up from Chevon and I only use the old style pumps which are hard to find with the dedicated line for each grade. New pumps all feed the reg, mid, and premium through one line. And I heard from someone to avoid using those if you have a choice so I go out of my way to not use them. VP Racing is the only place that offers 93 and up around here.

http://www.vpracingfuels.com/page535437.html

#11

Motor octane represents the “M” in R+M/2.

#12

Interesting point about the old school lines. Makes sense that the PetroCanada 94 around here usually has its own dedicated pump and line.

#13

I think that’s just people being paranoid. Someone using 87 before you and you fill up with 91… That will mean maybe one or two liters of 87 mixed in vs 30-60 liters of 91.

#14

So I heard from someone that the Summit Racing local to me here in town carries Adams Products. So I went over there last night to check it out and I was in and out in about 5 minutes or less. I went to start the car and it fires up and then the revs fall until it dies, I try again and the same thing. So on the third time since I was parked on the street I started it up, gave it gas to keep the revs up and put it in gear and took off… I drove home without CEL or further issue. Now I’m really curious as to whats going on here. I have a few ideas…

1- I have the 93 tune.
2- My ecu from factory ends in E the one from Zingo ended in D, I hear sometimes they don’t take to cloning, maybe I have an issue?
3- I have some other issue, that’s maybe unrelated.

#15

If you have been running the tune for awhile it wouldn’t be 1 or 2.

You can always mix better fuel in. Check out Toluene, it’s a popular additive in race fuel to bring up the octane level.

Depending on how far you drive each day, check your plugs and your vacuum lines. Winter blend fuels are getting replaced by summer blend fuels. When this happens some gas stations will get “bad” fuel from time to time. We use a fuel analyzer at work and you would be amazed how far off blends can be at the switch of each season. Maybe try a different station? Or, check the above mentioned things.

#16

I haven’t had the tune that long I just got it at their last BBQ. I got out my Vagcom and just started wondering through it checking things as I’m not really very experienced with it yet and this is what I came up with…

Where it says JHM V2/93, does that mean I have the 93 tune??

http://i1190.photobucket.com/albums/z457/A4QuattroV6/IMG_20130511_172045_256_zpsa1cf9409.jpg

#17

Are those fault codes active?

#18

What do you mean active? I don’t have a CEL on. They were just there when i checked the codes. I’ve had that Cylinder 5 code coming on and off for awhile now, whenever i disassemble that bank and swap coils or plugs it goes away for significant time and then comes back. The other codes I’ve never seen before. I think the issue with 5 is with a loose clip that when I take apart and put it back its fine, but then comes loose again. I think I may just need the red clips that hold the harness on because the one by 5 keeps coming unclipped, or at worst a new engine harness. I’ve already replaced the injector. And I’ve hard my tech repair the harness on that side so I know theres some intermittent issue there.

But I still know I have some issue with my fuel with the drastic changes in the car with different gas and I obviously need to run the proper octane. I REALLY hope I have the 93 tune because even if i did have the 91 I would be paying the extra $ for the 93 and I want to be able to have the higher tune to adapt to the VP100 because the car felt soooo good with the 93 and VP 100 mixed 5-1, it felt like a COMPLETELY different car on a whole other level that was sooo much more fun to drive. I could shift soo much faster and smoother through all the gears. Then I put the 91 in and the car starts to sputter immediately on pulling off from the gas station.

#19

Looking at ur vag read out you have the 93 tune. So the car will be sluggish if you put in 91 because its going into less power mode.

Also you have an issie in cylinder 5. The car is running on 1 less cylinder when that injector isnt workingso keep that Iin mind. The missfire shows you the cylinder isnt getting power having one less cylinder will deffinitly make the car feel stronger with the proper fuel and can also csuse the car to stall on a cold restart

#20

Using 91 in on a 93 tune may be the problem. I have 93 available everywhere around here, so I’ve never run anything less, even when I was stock, so I can’t really say that is the case.