Xylene before and after

[WyoSyclone]

While tuning with Code59 I ran up against the limits of my fuel/timing/boost settings... only 91 octane available here in Wyoming. This was causing me to back way off on my timing with my boost target of 18lbs. Getting frustrated not being able to find race fuel I decided to dump 2 gallons of xylene into my approximate 3/4 tank of 91 octane Shell.

On the first run I purposely kept my foot in it, even though I had 8.4 degrees of knock...just because I wanted a good comparison run. Pic 1 is before the xylene.

Pic 2 is after dumping the 2 gallons in... approximate 6 degrees reduction in KR shortly after TC lockup.... will try one more gallon of xylene - should be about right according to the formulas I've been able to find for mixing. Noticeable difference in power, able to run approximately 10 degrees more timing.

After this final test will be installing Julio's Alky system and going back to straight 91 octane.... xylene is between $16 and $18 a gallon up here right now

 

[4C FED]

Re: Xylene before and after

xylene is hard are the rubber hoses.
If you're only going to use it for a couple of times, probably no big deal.

 

[WyoSyclone]

Re: Xylene before and after

xylene is hard are the rubber hoses.
If you're only going to use it for a couple of times, probably no big deal.

Yup, if I was going to run it all the time I'd probably add the Marvel Mystery oil like a lot of people do.... this will be out of the tank within a week or so.

 

[Ross L]

Re: Xylene before and after

you'll have to run alot more than 18 psi with the alky. Good stuff!

 

[Foot Performance]

Re: Xylene before and after

Looks better than my DM I have no knock but only 11psi but the new turbo should help with that

 

[WyoSyclone]

Re: Xylene before and after

Looks better than my DM I have no knock but only 11psi but the new turbo should help with that

Yup, kind of a tricky game Brandon.... the Stage1 doesn't really get into its efficiency area on the compressor map till between 18 and 20 psi - running below that causes a relative upswing in IAT's. Once I get the Alky on I think I'll target 18.5psi... then it will be a matter of seeing what I can dial in for timing. When is your new turbo going on?

 

[Foot Performance]

Re: Xylene before and after

Yup, kind of a tricky game Brandon.... the Stage1 doesn't really get into its efficiency area on the compressor map till between 18 and 20 psi - running below that causes a relative upswing in IAT's. Once I get the Alky on I think I'll target 18.5psi... then it will be a matter of seeing what I can dial in for timing. When is your new turbo going on?

I need to get the exhuast housing coated and I get all the lines (I am going back all new) Then I will start tearing it apart:tup:

 

[turbodig]

Re: Xylene before and after

xylene is hard are the rubber hoses.
If you're only going to use it for a couple of times, probably no big deal.

Xylene is what's in unleaded race gas. In the concentrations Rob was running, it would take dozens of years to show any deterioration.

I've run it in vehicles for years, with the only issues being paint or exposed skin.

 

[turbodig]

Re: Xylene before and after

While tuning with Code59 I ran up against the limits of my fuel/timing/boost settings... only 91 octane available here in Wyoming. This was causing me to back way off on my timing with my boost target of 18lbs. Getting frustrated not being able to find race fuel I decided to dump 2 gallons of xylene into my approximate 3/4 tank of 91 octane Shell.

On the first run I purposely kept my foot in it, even though I had 8.4 degrees of knock...just because I wanted a good comparison run. Pic 1 is before the xylene.

Pic 2 is after dumping the 2 gallons in... approximate 6 degrees reduction in KR shortly after TC lockup.... will try one more gallon of xylene - should be about right according to the formulas I've been able to find for mixing. Noticeable difference in power, able to run approximately 10 degrees more timing.

One thing I'd suggest is turning your knock recovery rate way up... this will get rid of that slowly ramping down business.

Also, a couple of those look like an acoustic thing... what are your knock counts doing?

 

[WyoSyclone]

Re: Xylene before and after

One thing I'd suggest is turning your knock recovery rate way up... this will get rid of that slowly ramping down business.

Also, a couple of those look like an acoustic thing... what are your knock counts doing?

Thanks Dig.... I'll crank up on F6 to get rid of the slow decay ramp....
Knock counts start out at a high plateau (from what Josh says this was a remnant from a change in DM)... in this case the counts just stay at 4306 during cruise, never change (no KR). At the first onset of KR the counts go up to 4401, then just hangs there. The next larger step in KR causes counts to go from 4401 up to 4618... then they just stay there till the truck is turned off. I've always thought it was a bug in DM that caused the count rates to just keep adding on to themselves rather than settling back down via an averaging function.

 

[Deanzsyclone]

Re: Xylene before and after

I'd like to see the results after using "maxlead200". As long as you don't have a cat on the truck. This is what I throw in my sy.
http://www.maxlead2000.com/

 

[mrweelr]

Re: Xylene before and after

I used to use 91 mixed with Xylene or Torco unleaded race fuel concentrate. It definitely reduced or eliminated knock, but the Xylene is a hassle to poor into the tank (5 gallon drums) and Torco leaves an orange residue on the plugs, combustion chambers, and turbine wheel. With this new build, I'm going to be running 100 pump unleaded for daily driving and Sunoco 104 or VP Motorsport 103 or 109 unleaded for racing. Will also be spraying VP M5 methanol with the razor alky system for added protection. Never tried that stuff Dean mentioned, but I still have a cat and O2 sensor so that's a no-go.