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**DirtyD** · 10-24-2013, 12:12 PM

Originally Posted by JDBishopArts

Stock plugs? Did you gap down?

Originally Posted by JDBishopArts

And I don't know much about the correct timing for NA 5.0s but isn't 25 a bit high? I thought most were around 20-22 and the race tunes were 23-24. I'd either get another tune or back the timing off till it stops knocking. Some cars act different than others.

I've spoke with other people, and 25-27 is used a lot in tunes that are "track tunes" for people, but that is very aggressive. I originally had 22-23° of timing before I asked Kevin @ JPC to bump it up a little bit. He said it may hit the knock sensors, and it appears he was right. I'm getting back in touch with him shortly.

Originally Posted by wbt

I have used Shell fuel for years without issue.

Fuel from the local Exxon comes from the same refinery as the local Shell station. The differences are the additives used.

One thing to be on the lookout for is general age of said gas station. I don't buy gas from an older facility. Jobbers can mess up and put the wrong fuel in the wrong holding tanks as well. It happens more often than one might think.

Find a station of your choosing and monitor logs periodically to see how the car is doing.

DirtyD's problem isn't fuel. He has too much timing in his tune for the fuel he is using. My recommendations via PM were to reduce timing and richen it up a hair.

Thanks again for looking them over, wbt.

Originally Posted by 46Tbird

Shell is fine, QT is fine. Stay away from RaceTrac gas.

http://www.toptiergas.com/retailers.html

RaceTrac is just nasty period. Their drinks from the soda fountain aren't even good. I would never buy gas from them.

**JDBishopArts** · 10-24-2013, 12:37 PM

My recommendation is get Kevin @ Dunn Tuned to tune it. haha

My Dad was an petrol engineer for Exxon. While yes, most of the petroleum comes from the same place, the refining process and additives each gas producer adds are much different.

Most tuners prefer Exxon/Mobil, BP and QT gas. A lot of people having tuning problems were using Shell gas.

I learned a lot of this because when I went to tune my old Cobra at Gearheads I had filled up with Shell and it was pinging really bad. Luckily there wasn't a ton of fuel in there. We drained it and I filled up with QT and there was no problems.

Ford even recommended BP gas for years. I think they still do.

**DirtyD** · 10-24-2013, 12:48 PM

Originally Posted by JDBishopArts

My recommendation is get Kevin @ Dunn Tuned to tune it. haha

My Dad was an petrol engineer for Exxon. While yes, most of the petroleum comes from the same place, the refining process and additives each gas producer adds are much different.

Most tuners prefer Exxon/Mobil, BP and QT gas. A lot of people having tuning problems were using Shell gas.

I learned a lot of this because when I went to tune my old Cobra at Gearheads I had filled up with Shell and it was pinging really bad. Luckily there wasn't a ton of fuel in there. We drained it and I filled up with QT and there was no problems.

Ford even recommended BP gas for years. I think they still do.

But then how can Shell produce a inferior consumer gas but make one of the best race gases in the industry (URT)?

I've tried a few tanks of QT in my car, and the last one I did gave me horrible mileage, so I didn't go back. That could've been a number of factors, but who knows.

The guys at JPC have been great working with me, so that's why I'm giving them my business. I'm hopefully going to have Kevin tune it when I convert to corn, but I'll stick with them for now.

I'll try another gas next go around this weekend when I head down to Austin for a JDRF walk.

**JDBishopArts** · 10-24-2013, 01:06 PM

It's not that it's an "inferior gas". It's good fuel for normal cars. Not tuned performance cars. From what I read and have heard from 2 tuners they think it has something to do with the additives. Most tuners don't like it because it causes knock retard. Same thing you're experiencing. Look it up. You'll see tons of cases where people are having knock issues and using shell gas. They switch and it goes away.

There are very few things that can cause knock retard. But if you're commanding a certain degree of timing and the car is pulling it in my experience it can only be fuel or heat. It's not hot so that leaves fuel.

**JDBishopArts** · 10-24-2013, 01:08 PM

Buy Exxon. We have a lot of Exxon stock. lol.

**wbt** · 10-24-2013, 01:36 PM

So for the armchair quarterbacks who haven't seen his logs, explain to everyone how you have his issue nailed down to bad fuel. Basically you guys are guessing at the issue but have no data to back it up with. Just Internet hearsay. Makes sense.

**DirtyD** · 10-24-2013, 01:42 PM

As far as I'm aware, I wasn't pulling timing on the previous tune revisions and datalogs prior to the temperatures changing around here. But, I was not monitoring KS. Brent reviewed one of the logs in the warm air time period and said everything looked pretty good. These problems didn't surface, to my apparent knowledge, until I started doing these logs in cooler weather.

I'm going to switch to another gas this weekend and see what the logs show.

But I wonder if the whole nitrogen additive that SHell uses is partly to blame...lol

**JDBishopArts** · 10-24-2013, 01:59 PM

Originally Posted by wbt

So for the armchair quarterbacks who haven't seen his logs, explain to everyone how you have his issue nailed down to bad fuel. Basically you guys are guessing at the issue but have no data to back it up with. Just Internet hearsay. Makes sense.

lol This guy.

I'm trying to help him find a solution based off of the information I was given by Derek.

It's not internet hearsay. It's fact. Backed up by a million Elvis's.

Never said I had it 100% nailed down to fuel. It's a good place to start. There are a few things that can cause knock retard. Fuel being one of them. Shell gas caused knock retard on one of my own cars.

Cooler weather also means more dense air which means it can lean out a car which could also cause knock. Unless it's on a poor tune it shouldn't go so lean due to colder air to cause knock, which would also indicate fuel.

Either way, just trying to help a guy out with a problem.

**DirtyD** · 10-24-2013, 02:11 PM

Originally Posted by JDBishopArts

lol This guy.

I'm trying to help him find a solution based off of the information I was given by Derek.

It's not internet hearsay. It's fact. Backed up by a million Elvis's.

Never said I had it 100% nailed down to fuel. It's a good place to start. There are a few things that can cause knock retard. Fuel being one of them. Shell gas caused knock retard on one of my own cars.

Cooler weather also means more dense air which means it can lean out a car which could also cause knock. Unless it's on a poor tune it shouldn't go so lean due to colder air to cause knock, which would also indicate fuel.

Either way, just trying to help a guy out with a problem.

I appreciate the help Josh.

**BERT** · 10-24-2013, 02:11 PM

Originally Posted by wbt

So for the armchair quarterbacks who haven't seen his logs, explain to everyone how you have his issue nailed down to bad fuel. Basically you guys are guessing at the issue but have no data to back it up with. Just Internet hearsay. Makes sense.

It's the American way

**46Tbird** · 10-24-2013, 03:26 PM

Originally Posted by JDBishopArts

Ford even recommended BP gas for years. I think they still do.

Pretty sure this message was in the gas tank of every S197 Mustang up until the 'incident' in the gulf.

**kdanner** · 10-24-2013, 04:55 PM

Originally Posted by DirtyD

But then how can Shell produce a inferior consumer gas but make one of the best race gases in the industry (URT)?

It had their name on it, but they didn't make it. It also no longer exists. All that spamming of forums constantly and they still couldn't keep that program going.

I've had my best luck with Exxon. BP is good too but nearly nonexistent here. HEB has some nice E85 that always tests 85 to 90% here.

**TrueStreetTim** · 10-24-2013, 05:20 PM

Originally Posted by wbt

I have used Shell fuel for years without issue.

Fuel from the local Exxon comes from the same refinery as the local Shell station. The differences are the additives used.

One thing to be on the lookout for is general age of said gas station. I don't buy gas from an older facility. Jobbers can mess up and put the wrong fuel in the wrong holding tanks as well. It happens more often than one might think.

Find a station of your choosing and monitor logs periodically to see how the car is doing.

DirtyD's problem isn't fuel. He has too much timing in his tune for the fuel he is using. My recommendations via PM were to reduce timing and richen it up a hair.

Ditto. Probably the best thing you can do (regardless of refinery/company) is to use the more crowded stations. Stations off the beaten path dont get as many deliveries and fuel sits longer etc.

**DirtyD** · 10-24-2013, 07:33 PM

Originally Posted by kdanner

It had their name on it, but they didn't make it. It also no longer exists. All that spamming of forums constantly and they still couldn't keep that program going.

I've had my best luck with Exxon. BP is good too but nearly nonexistent here. HEB has some nice E85 that always tests 85 to 90% here.

We only have one HEB up here, but no E85. Hell, back in Houston is don't think many or any of the HEBs have E85.

Kroger is always good for E85 when you find a station that has it.

Opinions on Kroger gas? I'm running a tank right now and might see what my logs tell me.

**BV600** · 10-25-2013, 08:13 AM

Originally Posted by kdanner

It had their name on it, but they didn't make it. It also no longer exists. All that spamming of forums constantly and they still couldn't keep that program going.

I've had my best luck with Exxon. BP is good too but nearly nonexistent here. HEB has some nice E85 that always tests 85 to 90% here.

A friend that runs E85 here tested the HEB here and I believe it was 94%, and its like 60 cents cheaper than the other option around here which test lower.